From 0cb9248b2336b7a46bc0b5a79348975d9f5c0f02 Mon Sep 17 00:00:00 2001
From: tyranron <tyranron@gmail.com>
Date: Fri, 15 Oct 2021 13:05:03 +0300
Subject: [PATCH 01/25] Change `FromInputValue` signature and boostrap
 refactoring

---
 juniper/src/ast.rs                            |  39 ++--
 juniper/src/executor/mod.rs                   | 163 ++++++++--------
 .../introspection/input_object.rs             |   4 +-
 juniper/src/parser/tests/value.rs             |   2 +-
 juniper/src/schema/meta.rs                    | 180 +++++++++---------
 juniper/src/schema/schema.rs                  |   2 +-
 juniper/src/types/base.rs                     |  41 ++--
 juniper/src/types/nullable.rs                 |  16 +-
 juniper/src/value/mod.rs                      |   2 +-
 9 files changed, 233 insertions(+), 216 deletions(-)

diff --git a/juniper/src/ast.rs b/juniper/src/ast.rs
index 3ad050240..cb456a87d 100644
--- a/juniper/src/ast.rs
+++ b/juniper/src/ast.rs
@@ -152,20 +152,34 @@ pub type OwnedDocument<'a, S> = Vec<Definition<'a, S>>;
 
 /// Parse an unstructured input value into a Rust data type.
 ///
-/// The conversion _can_ fail, and must in that case return None. Implemented
-/// automatically by the convenience proc macro `graphql_scalar` or by deriving GraphQLEnum.
+/// The conversion _can_ fail, and must in that case return [`Err`]. Thus not
+/// restricted in the definition of this trait, the returned [`Err`] should be
+/// convertible with [`IntoFieldError`] to fit well into the library machinery.
+///
+/// Implemented automatically by the convenience proc macro [`graphql_scalar!`]
+/// or by deriving `GraphQLEnum`.
 ///
 /// Must be implemented manually when manually exposing new enums or scalars.
+///
+/// [`graphql_scalar!`]: macro@crate::graphql_scalar
+/// [`IntoFieldError`]: crate::IntoFieldError
 pub trait FromInputValue<S = DefaultScalarValue>: Sized {
+    /// Type of this conversion error.
+    ///
+    /// Thus not restricted, it should be convertible with [`IntoFieldError`] to
+    /// fit well into the library machinery.
+    type Error;
+
     /// Performs the conversion.
-    fn from_input_value(v: &InputValue<S>) -> Option<Self>;
+    fn from_input_value(v: &InputValue<S>) -> Result<Self, Self::Error>;
 
-    /// Performs the conversion from an absent value (e.g. to distinguish between
-    /// implicit and explicit null). The default implementation just uses
-    /// `from_input_value` as if an explicit null were provided.
+    /// Performs the conversion from an absent value (e.g. to distinguish
+    /// between implicit and explicit `null`).
     ///
-    /// This conversion must not fail.
-    fn from_implicit_null() -> Option<Self> {
+    /// The default implementation just calls
+    /// [`FromInputValue::from_input_value()`] as if an explicit `null` was
+    /// provided.
+    fn from_implicit_null() -> Result<Self, Self::Error> {
         Self::from_input_value(&InputValue::<S>::Null)
     }
 }
@@ -298,12 +312,9 @@ impl<S> InputValue<S> {
         }
     }
 
-    /// Shorthand form of invoking [`FromInputValue::from()`].
-    pub fn convert<T>(&self) -> Option<T>
-    where
-        T: FromInputValue<S>,
-    {
-        <T as FromInputValue<S>>::from_input_value(self)
+    /// Shorthand form of invoking [`FromInputValue::from_input_value()`].
+    pub fn convert<T: FromInputValue<S>>(&self) -> Result<T, T::Error> {
+        T::from_input_value(self)
     }
 
     /// Does the value represent a `null`?
diff --git a/juniper/src/executor/mod.rs b/juniper/src/executor/mod.rs
index c27cd843e..719ce7abc 100644
--- a/juniper/src/executor/mod.rs
+++ b/juniper/src/executor/mod.rs
@@ -149,47 +149,38 @@ where
 ///     Ok(s)
 /// }
 /// ```
-#[derive(Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 pub struct FieldError<S = DefaultScalarValue> {
     message: String,
     extensions: Value<S>,
 }
 
-impl<T: Display, S> From<T> for FieldError<S>
-where
-    S: crate::value::ScalarValue,
-{
-    fn from(e: T) -> FieldError<S> {
-        FieldError {
-            message: format!("{}", e),
-            extensions: Value::null(),
+impl<T: Display, S> From<T> for FieldError<S> {
+    fn from(e: T) -> Self {
+        Self {
+            message: e.to_string(),
+            extensions: Value::Null,
         }
     }
 }
 
 impl<S> FieldError<S> {
-    /// Construct a new error with additional data
-    ///
-    /// You can use the `graphql_value!` macro to construct an error:
+    /// Construct a new [`FieldError`] with additional data.
     ///
+    /// You can use the [`graphql_value!`] macro to construct an error:
     /// ```rust
-    /// use juniper::FieldError;
     /// # use juniper::DefaultScalarValue;
-    /// use juniper::graphql_value;
+    /// use juniper::{graphql_value, FieldError};
     ///
-    /// # fn sample() {
     /// # let _: FieldError<DefaultScalarValue> =
     /// FieldError::new(
     ///     "Could not open connection to the database",
-    ///     graphql_value!({ "internal_error": "Connection refused" })
+    ///     graphql_value!({"internal_error": "Connection refused"}),
     /// );
-    /// # }
-    /// # fn main() { }
     /// ```
     ///
-    /// The `extensions` parameter will be added to the `"extensions"` field of the error
-    /// object in the JSON response:
-    ///
+    /// The `extensions` parameter will be added to the `"extensions"` field of
+    /// the `"errors"` object in response:
     /// ```json
     /// {
     ///   "errors": [
@@ -202,25 +193,34 @@ impl<S> FieldError<S> {
     /// }
     /// ```
     ///
-    /// If the argument is `Value::null()`, no extra data will be included.
-    pub fn new<T: Display>(e: T, extensions: Value<S>) -> FieldError<S> {
-        FieldError {
-            message: format!("{}", e),
+    /// If the argument is [`Value::Null`], then no extra data will be included.
+    ///
+    /// [`graphql_value!`]: macro@crate::graphql_value
+    #[must_use]
+    pub fn new<T: Display>(e: T, extensions: Value<S>) -> Self {
+        Self {
+            message: e.to_string(),
             extensions,
         }
     }
 
-    #[doc(hidden)]
+    /// Returns `"message"` field of this [`FieldError`].
+    #[must_use]
     pub fn message(&self) -> &str {
         &self.message
     }
 
-    #[doc(hidden)]
+    /// Returns `"extensions"` field of this [`FieldError`].
+    ///
+    /// If there is none `"extensions"` then [`Value::Null`] will be returned.
+    #[must_use]
     pub fn extensions(&self) -> &Value<S> {
         &self.extensions
     }
 
-    /// Maps the [`ScalarValue`] type of this [`FieldError`] into the specified one.
+    /// Maps the [`ScalarValue`] type of this [`FieldError`] into the specified
+    /// one.
+    #[must_use]
     pub fn map_scalar_value<Into>(self) -> FieldError<Into>
     where
         S: ScalarValue,
@@ -246,17 +246,18 @@ pub type ValuesStream<'a, S = DefaultScalarValue> =
 /// The map of variables used for substitution during query execution
 pub type Variables<S = DefaultScalarValue> = HashMap<String, InputValue<S>>;
 
-/// Custom error handling trait to enable Error types other than `FieldError` to be specified
-/// as return value.
+/// Custom error handling trait to enable error types other than [`FieldError`]
+/// to be specified as return value.
 ///
-/// Any custom error type should implement this trait to convert it to `FieldError`.
+/// Any custom error type should implement this trait to convert itself to a
+/// [`FieldError`].
 pub trait IntoFieldError<S = DefaultScalarValue> {
-    #[doc(hidden)]
+    /// Performs the custom conversion into a [`FieldError`].
+    #[must_use]
     fn into_field_error(self) -> FieldError<S>;
 }
 
 impl<S1: ScalarValue, S2: ScalarValue> IntoFieldError<S2> for FieldError<S1> {
-    #[inline]
     fn into_field_error(self) -> FieldError<S2> {
         self.map_scalar_value()
     }
@@ -1125,22 +1126,21 @@ where
     Ok((value, errors))
 }
 
-impl<'r, S> Registry<'r, S>
-where
-    S: ScalarValue + 'r,
-{
-    /// Construct a new registry
-    pub fn new(types: FnvHashMap<Name, MetaType<'r, S>>) -> Registry<'r, S> {
-        Registry { types }
+impl<'r, S: 'r> Registry<'r, S> {
+    /// Constructs a new [`Registry`] out of the given `types`.
+    pub fn new(types: FnvHashMap<Name, MetaType<'r, S>>) -> Self {
+        Self { types }
     }
 
-    /// Get the `Type` instance for a given GraphQL type
+    /// Returns a [`Type`] instance for the given [`GraphQLType`], registered in
+    /// this [`Registry`].
     ///
-    /// If the registry hasn't seen a type with this name before, it will
-    /// construct its metadata and store it.
+    /// If this [`Registry`] hasn't seen a [`Type`] with such
+    /// [`GraphQLType::name`] before, it will construct the one and store it.
     pub fn get_type<T>(&mut self, info: &T::TypeInfo) -> Type<'r>
     where
         T: GraphQLType<S> + ?Sized,
+        S: ScalarValue,
     {
         if let Some(name) = T::name(info) {
             let validated_name = name.parse::<Name>().unwrap();
@@ -1158,10 +1158,11 @@ where
         }
     }
 
-    /// Create a field with the provided name
+    /// Creates a [`Field`] with the provided `name`.
     pub fn field<T>(&mut self, name: &str, info: &T::TypeInfo) -> Field<'r, S>
     where
         T: GraphQLType<S> + ?Sized,
+        S: ScalarValue,
     {
         Field {
             name: smartstring::SmartString::from(name),
@@ -1180,6 +1181,7 @@ where
     ) -> Field<'r, S>
     where
         I: GraphQLType<S>,
+        S: ScalarValue,
     {
         Field {
             name: smartstring::SmartString::from(name),
@@ -1190,18 +1192,19 @@ where
         }
     }
 
-    /// Create an argument with the provided name
+    /// Creates an [`Argument`] with the provided `name`.
     pub fn arg<T>(&mut self, name: &str, info: &T::TypeInfo) -> Argument<'r, S>
     where
-        T: GraphQLType<S> + FromInputValue<S> + ?Sized,
+        T: GraphQLType<S> + FromInputValue<S>,
+        S: ScalarValue,
     {
         Argument::new(name, self.get_type::<T>(info))
     }
 
-    /// Create an argument with a default value
+    /// Creates an [`Argument`] with the provided default `value`.
     ///
-    /// When called with type `T`, the actual argument will be given the type
-    /// `Option<T>`.
+    /// When called with type `T`, the actual [`Argument`] will be given the
+    /// type `Option<T>`.
     pub fn arg_with_default<T>(
         &mut self,
         name: &str,
@@ -1209,7 +1212,8 @@ where
         info: &T::TypeInfo,
     ) -> Argument<'r, S>
     where
-        T: GraphQLType<S> + ToInputValue<S> + FromInputValue<S> + ?Sized,
+        T: GraphQLType<S> + ToInputValue<S> + FromInputValue<S>,
+        S: ScalarValue,
     {
         Argument::new(name, self.get_type::<Option<T>>(info)).default_value(value.to_input_value())
     }
@@ -1220,40 +1224,45 @@ where
             .or_insert(MetaType::Placeholder(PlaceholderMeta { of_type }));
     }
 
-    /// Create a scalar meta type
-    ///
-    /// This expects the type to implement `FromInputValue`.
+    /// Creates a [`ScalarMeta`] type.
     pub fn build_scalar_type<T>(&mut self, info: &T::TypeInfo) -> ScalarMeta<'r, S>
     where
-        T: FromInputValue<S> + GraphQLType<S> + ParseScalarValue<S> + ?Sized + 'r,
+        T: GraphQLType<S> + FromInputValue<S> + ParseScalarValue<S> + 'r,
+        S: ScalarValue,
     {
-        let name = T::name(info).expect("Scalar types must be named. Implement name()");
+        let name = T::name(info).expect("Scalar types must be named. Implement `name()`");
+
         ScalarMeta::new::<T>(Cow::Owned(name.to_string()))
     }
 
-    /// Create a list meta type
-    pub fn build_list_type<T: GraphQLType<S> + ?Sized>(
+    /// Creates a [`ListMeta`] type.
+    ///
+    /// Specifying `expected_size` will be used to ensure that values of this
+    /// type will always match it.
+    pub fn build_list_type<T>(
         &mut self,
         info: &T::TypeInfo,
         expected_size: Option<usize>,
-    ) -> ListMeta<'r> {
+    ) -> ListMeta<'r>
+    where
+        T: GraphQLType<S> + ?Sized,
+        S: ScalarValue,
+    {
         let of_type = self.get_type::<T>(info);
         ListMeta::new(of_type, expected_size)
     }
 
-    /// Create a nullable meta type
-    pub fn build_nullable_type<T: GraphQLType<S> + ?Sized>(
-        &mut self,
-        info: &T::TypeInfo,
-    ) -> NullableMeta<'r> {
+    /// Creates a [`NullableMeta`] type.
+    pub fn build_nullable_type<T>(&mut self, info: &T::TypeInfo) -> NullableMeta<'r>
+    where
+        T: GraphQLType<S> + ?Sized,
+        S: ScalarValue,
+    {
         let of_type = self.get_type::<T>(info);
         NullableMeta::new(of_type)
     }
 
-    /// Create an object meta type
-    ///
-    /// To prevent infinite recursion by enforcing ordering, this returns a
-    /// function that needs to be called with the list of fields on the object.
+    /// Creates an [`ObjectMeta`] type with the given `fields`.
     pub fn build_object_type<T>(
         &mut self,
         info: &T::TypeInfo,
@@ -1261,6 +1270,7 @@ where
     ) -> ObjectMeta<'r, S>
     where
         T: GraphQLType<S> + ?Sized,
+        S: ScalarValue,
     {
         let name = T::name(info).expect("Object types must be named. Implement name()");
 
@@ -1269,22 +1279,22 @@ where
         ObjectMeta::new(Cow::Owned(name.to_string()), &v)
     }
 
-    /// Create an enum meta type
+    /// Creates an [`EnumMeta`] type out of the provided `values`.
     pub fn build_enum_type<T>(
         &mut self,
         info: &T::TypeInfo,
         values: &[EnumValue],
     ) -> EnumMeta<'r, S>
     where
-        T: FromInputValue<S> + GraphQLType<S> + ?Sized,
+        T: GraphQLType<S> + FromInputValue<S>,
+        S: ScalarValue,
     {
-        let name = T::name(info).expect("Enum types must be named. Implement name()");
+        let name = T::name(info).expect("Enum types must be named. Implement `name()`");
 
         EnumMeta::new::<T>(Cow::Owned(name.to_string()), values)
     }
 
-    /// Create an interface meta type,
-    /// by providing a type info object.
+    /// Creates an [`InterfaceMeta`] type with the given `fields`.
     pub fn build_interface_type<T>(
         &mut self,
         info: &T::TypeInfo,
@@ -1292,6 +1302,7 @@ where
     ) -> InterfaceMeta<'r, S>
     where
         T: GraphQLType<S> + ?Sized,
+        S: ScalarValue,
     {
         let name = T::name(info).expect("Interface types must be named. Implement name()");
 
@@ -1300,24 +1311,26 @@ where
         InterfaceMeta::new(Cow::Owned(name.to_string()), &v)
     }
 
-    /// Create a union meta type
+    /// Creates an [`UnionMeta`] type of the given `types`.
     pub fn build_union_type<T>(&mut self, info: &T::TypeInfo, types: &[Type<'r>]) -> UnionMeta<'r>
     where
         T: GraphQLType<S> + ?Sized,
+        S: ScalarValue,
     {
         let name = T::name(info).expect("Union types must be named. Implement name()");
 
         UnionMeta::new(Cow::Owned(name.to_string()), types)
     }
 
-    /// Create an input object meta type
+    /// Creates an [`InputObjectMeta`] type with the given `args`.
     pub fn build_input_object_type<T>(
         &mut self,
         info: &T::TypeInfo,
         args: &[Argument<'r, S>],
     ) -> InputObjectMeta<'r, S>
     where
-        T: FromInputValue<S> + GraphQLType<S> + ?Sized,
+        T: GraphQLType<S> + FromInputValue<S>,
+        S: ScalarValue,
     {
         let name = T::name(info).expect("Input object types must be named. Implement name()");
 
diff --git a/juniper/src/executor_tests/introspection/input_object.rs b/juniper/src/executor_tests/introspection/input_object.rs
index d9c48bda5..c924c3cad 100644
--- a/juniper/src/executor_tests/introspection/input_object.rs
+++ b/juniper/src/executor_tests/introspection/input_object.rs
@@ -209,9 +209,9 @@ fn default_name_input_value() {
         .collect(),
     );
 
-    let dv: Option<DefaultName> = FromInputValue::from_input_value(&iv);
+    let dv = DefaultName::from_input_value(&iv);
 
-    assert!(dv.is_some());
+    assert!(dv.is_ok(), "error: {}", dv.unwrap_err());
 
     let dv = dv.unwrap();
 
diff --git a/juniper/src/parser/tests/value.rs b/juniper/src/parser/tests/value.rs
index c8b1ac9b9..e3f4fe81c 100644
--- a/juniper/src/parser/tests/value.rs
+++ b/juniper/src/parser/tests/value.rs
@@ -55,7 +55,7 @@ impl Query {
 
 fn scalar_meta<T>(name: &'static str) -> MetaType<DefaultScalarValue>
 where
-    T: FromInputValue<DefaultScalarValue> + ParseScalarValue<DefaultScalarValue> + 'static,
+    T: FromInputValue<DefaultScalarValue> + ParseScalarValue<DefaultScalarValue>,
 {
     MetaType::Scalar(ScalarMeta::new::<T>(name.into()))
 }
diff --git a/juniper/src/schema/meta.rs b/juniper/src/schema/meta.rs
index 6566df910..e7f4e8cf6 100644
--- a/juniper/src/schema/meta.rs
+++ b/juniper/src/schema/meta.rs
@@ -407,16 +407,13 @@ impl<'a, S> MetaType<'a, S> {
     }
 }
 
-impl<'a, S> ScalarMeta<'a, S>
-where
-    S: ScalarValue + 'a,
-{
-    /// Build a new scalar type metadata with the specified name
+impl<'a, S> ScalarMeta<'a, S> {
+    /// Builds a new [`ScalarMeta`] type with the specified `name`.
     pub fn new<T>(name: Cow<'a, str>) -> Self
     where
-        T: FromInputValue<S> + ParseScalarValue<S> + 'a,
+        T: FromInputValue<S> + ParseScalarValue<S>,
     {
-        ScalarMeta {
+        Self {
             name,
             description: None,
             try_parse_fn: try_parse_fn::<S, T>,
@@ -424,22 +421,25 @@ where
         }
     }
 
-    /// Set the description for the given scalar type
+    /// Sets the `description` of this [`ScalarMeta`] type.
     ///
-    /// If a description already was set prior to calling this method, it will be overwritten.
-    pub fn description(mut self, description: &str) -> ScalarMeta<'a, S> {
+    /// Overwrites any previously set description.
+    pub fn description(mut self, description: &str) -> Self {
         self.description = Some(description.to_owned());
         self
     }
 
-    /// Wrap the scalar in a generic meta type
+    /// Wraps this [`ScalarMeta`] type into a generic [`MetaType`].
     pub fn into_meta(self) -> MetaType<'a, S> {
         MetaType::Scalar(self)
     }
 }
 
 impl<'a> ListMeta<'a> {
-    /// Build a new list type by wrapping the specified type
+    /// Build a new [`ListMeta`] type by wrapping the specified [`Type`].
+    ///
+    /// Specifying `expected_size` will be used to ensure that values of this
+    /// type will always match it.
     pub fn new(of_type: Type<'a>, expected_size: Option<usize>) -> Self {
         Self {
             of_type,
@@ -447,31 +447,28 @@ impl<'a> ListMeta<'a> {
         }
     }
 
-    /// Wrap the list in a generic meta type
+    /// Wraps this [`ListMeta`] type into a generic [`MetaType`].
     pub fn into_meta<S>(self) -> MetaType<'a, S> {
         MetaType::List(self)
     }
 }
 
 impl<'a> NullableMeta<'a> {
-    /// Build a new nullable type by wrapping the specified type
-    pub fn new(of_type: Type<'a>) -> NullableMeta<'a> {
-        NullableMeta { of_type }
+    /// Build a new [`NullableMeta`] type by wrapping the specified [`Type`].
+    pub fn new(of_type: Type<'a>) -> Self {
+        Self { of_type }
     }
 
-    /// Wrap the nullable type in a generic meta type
+    /// Wraps this [`NullableMeta`] type into a generic [`MetaType`].
     pub fn into_meta<S>(self) -> MetaType<'a, S> {
         MetaType::Nullable(self)
     }
 }
 
-impl<'a, S> ObjectMeta<'a, S>
-where
-    S: ScalarValue,
-{
-    /// Build a new object type with the specified name and fields
+impl<'a, S> ObjectMeta<'a, S> {
+    /// Build a new [`ObjectMeta`] type with the specified `name` and `fields`.
     pub fn new(name: Cow<'a, str>, fields: &[Field<'a, S>]) -> Self {
-        ObjectMeta {
+        Self {
             name,
             description: None,
             fields: fields.to_vec(),
@@ -479,19 +476,18 @@ where
         }
     }
 
-    /// Set the description for the object
+    /// Sets the `description` of this [`ObjectMeta`] type.
     ///
-    /// If a description was provided prior to calling this method, it will be overwritten.
-    pub fn description(mut self, description: &str) -> ObjectMeta<'a, S> {
+    /// Overwrites any previously set description.
+    pub fn description(mut self, description: &str) -> Self {
         self.description = Some(description.to_owned());
         self
     }
 
-    /// Set the interfaces this type implements
+    /// Set the `interfaces` this [`ObjectMeta`] type implements.
     ///
-    /// If a list of interfaces already was provided prior to calling this method, they will be
-    /// overwritten.
-    pub fn interfaces(mut self, interfaces: &[Type<'a>]) -> ObjectMeta<'a, S> {
+    /// Overwrites any previously set list of interfaces.
+    pub fn interfaces(mut self, interfaces: &[Type<'a>]) -> Self {
         self.interface_names = interfaces
             .iter()
             .map(|t| t.innermost_name().to_owned())
@@ -499,74 +495,71 @@ where
         self
     }
 
-    /// Wrap this object type in a generic meta type
+    /// Wraps this [`ObjectMeta`] type into a generic [`MetaType`].
     pub fn into_meta(self) -> MetaType<'a, S> {
         MetaType::Object(self)
     }
 }
 
-impl<'a, S> EnumMeta<'a, S>
-where
-    S: ScalarValue + 'a,
-{
-    /// Build a new enum type with the specified name and possible values
+impl<'a, S> EnumMeta<'a, S> {
+    /// Build a new [`EnumMeta`] type with the specified `name` and possible
+    /// `values`.
     pub fn new<T>(name: Cow<'a, str>, values: &[EnumValue]) -> Self
     where
         T: FromInputValue<S>,
     {
-        EnumMeta {
+        Self {
             name,
             description: None,
-            values: values.to_vec(),
+            values: values.to_owned(),
             try_parse_fn: try_parse_fn::<S, T>,
         }
     }
 
-    /// Set the description of the type
+    /// Sets the `description` of this [`EnumMeta`] type.
     ///
-    /// If a description was provided prior to calling this method, it will be overwritten
-    pub fn description(mut self, description: &str) -> EnumMeta<'a, S> {
+    /// Overwrites any previously set description.
+    pub fn description(mut self, description: &str) -> Self {
         self.description = Some(description.to_owned());
         self
     }
 
-    /// Wrap this enum type in a generic meta type
+    /// Wraps this [`EnumMeta`] type into a generic [`MetaType`].
     pub fn into_meta(self) -> MetaType<'a, S> {
         MetaType::Enum(self)
     }
 }
 
-impl<'a, S> InterfaceMeta<'a, S>
-where
-    S: ScalarValue,
-{
-    /// Build a new interface type with the specified name and fields
-    pub fn new(name: Cow<'a, str>, fields: &[Field<'a, S>]) -> InterfaceMeta<'a, S> {
-        InterfaceMeta {
+impl<'a, S> InterfaceMeta<'a, S> {
+    /// Builds a new [`InterfaceMeta`] type with the specified `name` and
+    /// `fields`.
+    pub fn new(name: Cow<'a, str>, fields: &[Field<'a, S>]) -> Self {
+        Self {
             name,
             description: None,
-            fields: fields.to_vec(),
+            fields: fields.to_owned(),
         }
     }
 
-    /// Set the description of the type
+    /// Sets the `description` of this [`InterfaceMeta`] type.
     ///
-    /// If a description was provided prior to calling this method, it will be overwritten.
-    pub fn description(mut self, description: &str) -> InterfaceMeta<'a, S> {
+    /// Overwrites any previously set description.
+    pub fn description(mut self, description: &str) -> Self {
         self.description = Some(description.to_owned());
         self
     }
 
-    /// Wrap this interface type in a generic meta type
+    /// Wraps this [`InterfaceMeta`] type into a generic [`MetaType`].
     pub fn into_meta(self) -> MetaType<'a, S> {
         MetaType::Interface(self)
     }
 }
 
 impl<'a> UnionMeta<'a> {
-    /// Build a new union type with the specified name and possible types
-    pub fn new(name: Cow<'a, str>, of_types: &[Type]) -> UnionMeta<'a> {
-        UnionMeta {
+    /// Build a new [`UnionMeta`] type with the specified `name` and possible
+    /// [`Type`]s.
+    pub fn new(name: Cow<'a, str>, of_types: &[Type]) -> Self {
+        Self {
             name,
             description: None,
             of_type_names: of_types
@@ -576,61 +569,59 @@ impl<'a> UnionMeta<'a> {
         }
     }
 
-    /// Set the description of the type
+    /// Sets the `description` of this [`UnionMeta`] type.
     ///
-    /// If a description was provided prior to calling this method, it will be overwritten.
-    pub fn description(mut self, description: &str) -> UnionMeta<'a> {
+    /// Overwrites any previously set description.
+    pub fn description(mut self, description: &str) -> Self {
         self.description = Some(description.to_owned());
         self
     }
 
-    /// Wrap this union type in a generic meta type
+    /// Wraps this [`UnionMeta`] type into a generic [`MetaType`].
     pub fn into_meta<S>(self) -> MetaType<'a, S> {
         MetaType::Union(self)
     }
 }
 
-impl<'a, S> InputObjectMeta<'a, S>
-where
-    S: ScalarValue,
-{
-    /// Build a new input type with the specified name and input fields
+impl<'a, S> InputObjectMeta<'a, S> {
+    /// Builds a new [`InputObjectMeta`] type with the specified `name` and
+    /// `input_fields`.
     pub fn new<T>(name: Cow<'a, str>, input_fields: &[Argument<'a, S>]) -> Self
     where
-        T: FromInputValue<S> + ?Sized,
+        T: FromInputValue<S>,
     {
-        InputObjectMeta {
+        Self {
             name,
             description: None,
-            input_fields: input_fields.to_vec(),
+            input_fields: input_fields.to_owned(),
             try_parse_fn: try_parse_fn::<S, T>,
         }
     }
 
-    /// Set the description of the type
+    /// Set the `description` of this [`InputObjectMeta`] type.
     ///
-    /// If a description was provided prior to calling this method, it will be overwritten.
-    pub fn description(mut self, description: &str) -> InputObjectMeta<'a, S> {
+    /// Overwrites any previously set description.
+    pub fn description(mut self, description: &str) -> Self {
         self.description = Some(description.to_owned());
         self
     }
 
-    /// Wrap this union type in a generic meta type
+    /// Wraps this [`InputObjectMeta`] type into a generic [`MetaType`].
     pub fn into_meta(self) -> MetaType<'a, S> {
         MetaType::InputObject(self)
     }
 }
 
 impl<'a, S> Field<'a, S> {
-    /// Set the description of the field
+    /// Set the `description` of this [`Field`].
     ///
-    /// This overwrites the description if any was previously set.
+    /// Overwrites any previously set description.
     pub fn description(mut self, description: &str) -> Self {
         self.description = Some(description.to_owned());
         self
     }
 
-    /// Add an argument to the field
+    /// Adds an `argument` to this [`Field`].
     ///
     /// Arguments are unordered and can't contain duplicates by name.
     pub fn argument(mut self, argument: Argument<'a, S>) -> Self {
@@ -642,13 +633,12 @@ impl<'a, S> Field<'a, S> {
                 args.push(argument);
             }
         };
-
         self
     }
 
-    /// Set the field to be deprecated with an optional reason.
+    /// Sets this [`Field`] as deprecated with an optional `reason`.
     ///
-    /// This overwrites the deprecation reason if any was previously set.
+    /// Overwrites any previously set deprecation reason.
     pub fn deprecated(mut self, reason: Option<&str>) -> Self {
         self.deprecation_status = DeprecationStatus::Deprecated(reason.map(ToOwned::to_owned));
         self
@@ -656,7 +646,7 @@ impl<'a, S> Field<'a, S> {
 }
 
 impl<'a, S> Argument<'a, S> {
-    #[doc(hidden)]
+    /// Builds a new [`Argument`] of the given [`Type`] with the given `name`.
     pub fn new(name: &str, arg_type: Type<'a>) -> Self {
         Self {
             name: name.to_owned(),
@@ -666,44 +656,44 @@ impl<'a, S> Argument<'a, S> {
         }
     }
 
-    /// Set the description of the argument
+    /// Sets the `description` of this [`Argument`].
     ///
-    /// This overwrites the description if any was previously set.
+    /// Overwrites any previously set description.
     pub fn description(mut self, description: &str) -> Self {
         self.description = Some(description.to_owned());
         self
     }
 
-    /// Set the default value of the argument
+    /// Set the default value of this [`Argument`].
     ///
-    /// This overwrites the default value if any was previously set.
-    pub fn default_value(mut self, default_value: InputValue<S>) -> Self {
-        self.default_value = Some(default_value);
+    /// Overwrites any previously set default value.
+    pub fn default_value(mut self, val: InputValue<S>) -> Self {
+        self.default_value = Some(val);
         self
     }
 }
 
 impl EnumValue {
-    /// Construct a new enum value with the provided name
-    pub fn new(name: &str) -> EnumValue {
-        EnumValue {
+    /// Constructs a new [`EnumValue`] with the provided `name`.
+    pub fn new(name: &str) -> Self {
+        Self {
             name: name.to_owned(),
             description: None,
             deprecation_status: DeprecationStatus::Current,
         }
     }
 
-    /// Set the description of the enum value
+    /// Sets the `description` of this [`EnumValue`].
     ///
-    /// This overwrites the description if any was previously set.
-    pub fn description(mut self, description: &str) -> EnumValue {
+    /// Overwrites any previously set description.
+    pub fn description(mut self, description: &str) -> Self {
         self.description = Some(description.to_owned());
         self
     }
 
-    /// Set the enum value to be deprecated with an optional reason.
+    /// Sets this [`EnumValue`] as deprecated with an optional `reason`.
     ///
-    /// This overwrites the deprecation reason if any was previously set.
+    /// Overwrites any previously set deprecation reason.
     pub fn deprecated(mut self, reason: Option<&str>) -> Self {
         self.deprecation_status = DeprecationStatus::Deprecated(reason.map(ToOwned::to_owned));
         self
@@ -743,5 +733,5 @@ fn try_parse_fn<S, T>(v: &InputValue<S>) -> bool
 where
     T: FromInputValue<S>,
 {
-    <T as FromInputValue<S>>::from_input_value(v).is_some()
+    T::from_input_value(v).is_ok()
 }
diff --git a/juniper/src/schema/schema.rs b/juniper/src/schema/schema.rs
index 5651ccff5..ee947fee5 100644
--- a/juniper/src/schema/schema.rs
+++ b/juniper/src/schema/schema.rs
@@ -68,7 +68,7 @@ where
                 .replaced_context(&self.schema)
                 .resolve(&(), &self.schema),
             "__type" => {
-                let type_name: String = args.get("name").unwrap();
+                let type_name: String = args.get("name")?.unwrap();
                 executor
                     .replaced_context(&self.schema)
                     .resolve(&(), &self.schema.type_by_name(&type_name))
diff --git a/juniper/src/types/base.rs b/juniper/src/types/base.rs
index 45d6b703b..e06d5e943 100644
--- a/juniper/src/types/base.rs
+++ b/juniper/src/types/base.rs
@@ -6,7 +6,7 @@ use crate::{
     parser::Spanning,
     schema::meta::{Argument, MetaType},
     value::{DefaultScalarValue, Object, ScalarValue, Value},
-    GraphQLEnum,
+    GraphQLEnum, IntoFieldError, FieldResult
 };
 
 /// GraphQL type kind
@@ -73,10 +73,7 @@ pub struct Arguments<'a, S = DefaultScalarValue> {
     args: Option<IndexMap<&'a str, InputValue<S>>>,
 }
 
-impl<'a, S> Arguments<'a, S>
-where
-    S: ScalarValue,
-{
+impl<'a, S> Arguments<'a, S> {
     #[doc(hidden)]
     pub fn new(
         mut args: Option<IndexMap<&'a str, InputValue<S>>>,
@@ -86,34 +83,42 @@ where
             args = Some(IndexMap::new());
         }
 
-        if let (&mut Some(ref mut args), &Some(ref meta_args)) = (&mut args, meta_args) {
+        if let (Some(args), Some(meta_args)) = (&mut args, meta_args) {
             for arg in meta_args {
-                if !args.contains_key(arg.name.as_str()) || args[arg.name.as_str()].is_null() {
-                    if let Some(ref default_value) = arg.default_value {
-                        args.insert(arg.name.as_str(), default_value.clone());
+                let arg_name = arg.name.as_str();
+                if args.get(arg_name).map_or(true, InputValue::is_null) {
+                    if let Some(val) = &arg.default_value {
+                        args.insert(arg_name, val.clone());
                     }
                 }
             }
         }
 
-        Arguments { args }
+        Self { args }
     }
 
-    /// Get and convert an argument into the desired type.
+    /// Gets an argument by the given `name` and converts it into the desired
+    /// type.
+    ///
+    /// If the argument is found, or a default argument has been provided, the
+    /// given [`InputValue`] will be converted into the type `T`.
+    ///
+    /// Returns [`None`] if an argument with such `name` is not present.
     ///
-    /// If the argument is found, or a default argument has been provided,
-    /// the `InputValue` will be converted into the type `T`.
+    /// # Errors
     ///
-    /// Returns `Some` if the argument is present _and_ type conversion
-    /// succeeds.
-    pub fn get<T>(&self, key: &str) -> Option<T>
+    /// If the [`FromInputValue`] conversion fails.
+    pub fn get<T>(&self, name: &str) -> FieldResult<Option<T>, S>
     where
         T: FromInputValue<S>,
+        T::Error: IntoFieldError<S>,
     {
         self.args
             .as_ref()
-            .and_then(|args| args.get(key))
-            .and_then(InputValue::convert)
+            .and_then(|args| args.get(name))
+            .map(InputValue::convert)
+            .transpose()
+            .map_err(IntoFieldError::into_field_error)
     }
 }
 
diff --git a/juniper/src/types/nullable.rs b/juniper/src/types/nullable.rs
index e463f74d2..81341c597 100644
--- a/juniper/src/types/nullable.rs
+++ b/juniper/src/types/nullable.rs
@@ -278,20 +278,18 @@ where
     }
 }
 
-impl<S, T> FromInputValue<S> for Nullable<T>
-where
-    T: FromInputValue<S>,
-    S: ScalarValue,
-{
-    fn from_input_value(v: &InputValue<S>) -> Option<Nullable<T>> {
+impl<S, T: FromInputValue<S>> FromInputValue<S> for Nullable<T> {
+    type Error = <T as FromInputValue<S>>::Error;
+
+    fn from_input_value(v: &InputValue<S>) -> Result<Self, Self::Error> {
         match v {
-            &InputValue::Null => Some(Self::ExplicitNull),
+            &InputValue::Null => Ok(Self::ExplicitNull),
             v => v.convert().map(Self::Some),
         }
     }
 
-    fn from_implicit_null() -> Option<Self> {
-        Some(Self::ImplicitNull)
+    fn from_implicit_null() -> Result<Self, Self::Error> {
+        Ok(Self::ImplicitNull)
     }
 }
 
diff --git a/juniper/src/value/mod.rs b/juniper/src/value/mod.rs
index ce37ad001..3ca6c4137 100644
--- a/juniper/src/value/mod.rs
+++ b/juniper/src/value/mod.rs
@@ -26,7 +26,7 @@ pub use self::{
 /// values or variables. Also, lists and objects do not contain any location
 /// information since they are generated by resolving fields and values rather
 /// than parsing a source query.
-#[derive(Debug, PartialEq, Clone)]
+#[derive(Clone, Debug, PartialEq)]
 #[allow(missing_docs)]
 pub enum Value<S = DefaultScalarValue> {
     Null,

From 584f9ae3403d4289f3ed5abec6381578e3219b15 Mon Sep 17 00:00:00 2001
From: tyranron <tyranron@gmail.com>
Date: Fri, 15 Oct 2021 13:05:23 +0300
Subject: [PATCH 02/25] Refactor primitive types, vol.1

---
 juniper/src/types/containers.rs | 66 +++++++++++++++++++--------------
 1 file changed, 39 insertions(+), 27 deletions(-)

diff --git a/juniper/src/types/containers.rs b/juniper/src/types/containers.rs
index e4977fb0b..9aa542bda 100644
--- a/juniper/src/types/containers.rs
+++ b/juniper/src/types/containers.rs
@@ -80,28 +80,22 @@ where
     }
 }
 
-impl<S, T> FromInputValue<S> for Option<T>
-where
-    T: FromInputValue<S>,
-    S: ScalarValue,
-{
-    fn from_input_value(v: &InputValue<S>) -> Option<Self> {
+impl<S, T: FromInputValue<S>> FromInputValue<S> for Option<T> {
+    type Error = T::Error;
+
+    fn from_input_value(v: &InputValue<S>) -> Result<Self, Self::Error> {
         match v {
-            &InputValue::Null => Some(None),
+            &InputValue::Null => Ok(None),
             v => v.convert().map(Some),
         }
     }
 }
 
-impl<S, T> ToInputValue<S> for Option<T>
-where
-    T: ToInputValue<S>,
-    S: ScalarValue,
-{
+impl<S, T: ToInputValue<S>> ToInputValue<S> for Option<T> {
     fn to_input_value(&self) -> InputValue<S> {
-        match *self {
-            Some(ref v) => v.to_input_value(),
-            None => InputValue::null(),
+        match self {
+            Some(v) => v.to_input_value(),
+            None => InputValue::Null,
         }
     }
 }
@@ -163,18 +157,16 @@ where
     }
 }
 
-impl<T, S> FromInputValue<S> for Vec<T>
-where
-    T: FromInputValue<S>,
-    S: ScalarValue,
-{
-    fn from_input_value(v: &InputValue<S>) -> Option<Self> {
-        match *v {
-            InputValue::List(ref ls) => {
-                let v: Vec<_> = ls.iter().filter_map(|i| i.item.convert()).collect();
-                (v.len() == ls.len()).then(|| v)
-            }
-            ref other => other.convert().map(|e| vec![e]),
+impl<S, T: FromInputValue<S>> FromInputValue<S> for Vec<T> {
+    type Error = T::Error;
+
+    fn from_input_value(v: &InputValue<S>) -> Result<Self, Self::Error> {
+        match v {
+            InputValue::List(l) => l.iter().map(|i| i.item.convert()).collect(),
+            // See "Input Coercion" on List types:
+            // https://spec.graphql.org/June2018/#sec-Type-System.List
+            InputValue::Null => Ok(Vec::new()),
+            other => other.convert().map(|e| vec![e]),
         }
     }
 }
@@ -492,3 +484,23 @@ where
 
     Ok(Value::list(values))
 }
+
+#[cfg(test)]
+mod coercion {
+    use crate::{FromInputValue as _, InputValue};
+
+    // See "Input Coercion" examples on List types:
+    // https://spec.graphql.org/June2018/#sec-Type-System.List
+    #[test]
+    fn vec() {
+        assert_eq!(
+            <Vec<i32>>::from_input_value(&InputValue::list(vec![
+                InputValue::scalar(1),
+                InputValue::scalar(2),
+                InputValue::scalar(3)
+            ])),
+            Ok(vec![1, 2, 3]),
+        );
+        // TODO: all examples
+    }
+}

From e5481a0f8e15ca9bdf05eee32f93d5155d9ea078 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Tue, 23 Nov 2021 10:55:41 +0300
Subject: [PATCH 03/25] Update actix beta

---
 docs/book/content/advanced/dataloaders.md |  2 +-
 examples/actix_subscriptions/Cargo.toml   |  4 +-
 juniper_actix/Cargo.toml                  | 12 ++--
 juniper_actix/src/lib.rs                  | 67 ++++++++++++-----------
 4 files changed, 44 insertions(+), 41 deletions(-)

diff --git a/docs/book/content/advanced/dataloaders.md b/docs/book/content/advanced/dataloaders.md
index 8dd2f858a..fe172d1db 100644
--- a/docs/book/content/advanced/dataloaders.md
+++ b/docs/book/content/advanced/dataloaders.md
@@ -48,7 +48,7 @@ DataLoader caching does not replace Redis, Memcache, or any other shared applica
 
 ```toml
 [dependencies]
-actix-identity = "0.4.0-beta.2"
+actix-identity = "0.4.0-beta.4"
 actix-rt = "1.0"
 actix-web = {version = "2.0", features = []}
 juniper = { git = "https://github.com/graphql-rust/juniper" }
diff --git a/examples/actix_subscriptions/Cargo.toml b/examples/actix_subscriptions/Cargo.toml
index 95bf4898f..3cf886146 100644
--- a/examples/actix_subscriptions/Cargo.toml
+++ b/examples/actix_subscriptions/Cargo.toml
@@ -6,8 +6,8 @@ authors = ["Mihai Dinculescu <mihai.dinculescu@outlook.com>"]
 publish = false
 
 [dependencies]
-actix-web = "4.0.0-beta.8"
-actix-cors = "0.6.0-beta.2"
+actix-web = "4.0.0-beta.12"
+actix-cors = "0.6.0-beta.4"
 futures = "0.3"
 env_logger = "0.9"
 serde = "1.0"
diff --git a/juniper_actix/Cargo.toml b/juniper_actix/Cargo.toml
index fb01ee657..d5730bd7c 100644
--- a/juniper_actix/Cargo.toml
+++ b/juniper_actix/Cargo.toml
@@ -13,10 +13,10 @@ subscriptions = ["juniper_graphql_ws", "tokio"]
 
 [dependencies]
 actix = "0.12"
-actix-http = "3.0.0-beta.8"
+actix-http = "3.0.0-beta.13"
 http = "0.2.4"
-actix-web = "4.0.0-beta.8"
-actix-web-actors = "4.0.0-beta.6"
+actix-web = "4.0.0-beta.12"
+actix-web-actors = "4.0.0-beta.7"
 
 juniper = { version = "0.15.7", path = "../juniper", default-features = false }
 juniper_graphql_ws = { version = "0.3.0", path = "../juniper_graphql_ws", optional = true }
@@ -30,11 +30,11 @@ tokio = { version = "1.0", features = ["sync"], optional = true }
 
 [dev-dependencies]
 actix-rt = "2"
-actix-cors = "0.6.0-beta.2"
-actix-identity = "0.4.0-beta.2"
+actix-cors = "0.6.0-beta.4"
+actix-identity = "0.4.0-beta.4"
 tokio = "1.0"
 async-stream = "0.3"
-actix-test = "0.1.0-beta.3"
+actix-test = "0.1.0-beta.6"
 
 juniper = { version = "0.15.7", path = "../juniper", features = ["expose-test-schema"] }
 
diff --git a/juniper_actix/src/lib.rs b/juniper_actix/src/lib.rs
index 279f246a6..ec299adef 100644
--- a/juniper_actix/src/lib.rs
+++ b/juniper_actix/src/lib.rs
@@ -467,7 +467,14 @@ pub mod subscriptions {
 #[cfg(test)]
 mod tests {
     use actix_http::body::AnyBody;
-    use actix_web::{dev::ServiceResponse, http, http::header::CONTENT_TYPE, test, web::Data, App};
+    use actix_web::{
+        dev::ServiceResponse,
+        http,
+        http::header::CONTENT_TYPE,
+        test::{call_service, init_service, TestRequest},
+        web::Data,
+        App,
+    };
     use juniper::{
         http::tests::{run_http_test_suite, HttpIntegration, TestResponse},
         tests::fixtures::starwars::schema::{Database, Query},
@@ -507,14 +514,13 @@ mod tests {
         async fn graphql_handler() -> Result<HttpResponse, Error> {
             graphiql_handler("/abcd", None).await
         }
-        let mut app =
-            test::init_service(App::new().route("/", web::get().to(graphql_handler))).await;
-        let req = test::TestRequest::get()
+        let mut app = init_service(App::new().route("/", web::get().to(graphql_handler))).await;
+        let req = TestRequest::get()
             .uri("/")
             .append_header((ACCEPT, "text/html"))
             .to_request();
 
-        let resp = test::call_service(&mut app, req).await;
+        let resp = call_service(&mut app, req).await;
         assert_eq!(resp.status(), http::StatusCode::OK);
     }
 
@@ -523,14 +529,13 @@ mod tests {
         async fn graphql_handler() -> Result<HttpResponse, Error> {
             graphiql_handler("/dogs-api/graphql", Some("/dogs-api/subscriptions")).await
         }
-        let mut app =
-            test::init_service(App::new().route("/", web::get().to(graphql_handler))).await;
-        let req = test::TestRequest::get()
+        let mut app = init_service(App::new().route("/", web::get().to(graphql_handler))).await;
+        let req = TestRequest::get()
             .uri("/")
             .append_header((ACCEPT, "text/html"))
             .to_request();
 
-        let mut resp = test::call_service(&mut app, req).await;
+        let mut resp = call_service(&mut app, req).await;
         let body = take_response_body_string(&mut resp).await;
         assert_eq!(resp.status(), http::StatusCode::OK);
         assert_eq!(
@@ -548,14 +553,13 @@ mod tests {
         async fn graphql_handler() -> Result<HttpResponse, Error> {
             playground_handler("/abcd", None).await
         }
-        let mut app =
-            test::init_service(App::new().route("/", web::get().to(graphql_handler))).await;
-        let req = test::TestRequest::get()
+        let mut app = init_service(App::new().route("/", web::get().to(graphql_handler))).await;
+        let req = TestRequest::get()
             .uri("/")
             .append_header((ACCEPT, "text/html"))
             .to_request();
 
-        let resp = test::call_service(&mut app, req).await;
+        let resp = call_service(&mut app, req).await;
         assert_eq!(resp.status(), http::StatusCode::OK);
     }
 
@@ -564,14 +568,13 @@ mod tests {
         async fn graphql_handler() -> Result<HttpResponse, Error> {
             playground_handler("/dogs-api/graphql", Some("/dogs-api/subscriptions")).await
         }
-        let mut app =
-            test::init_service(App::new().route("/", web::get().to(graphql_handler))).await;
-        let req = test::TestRequest::get()
+        let mut app = init_service(App::new().route("/", web::get().to(graphql_handler))).await;
+        let req = TestRequest::get()
             .uri("/")
             .append_header((ACCEPT, "text/html"))
             .to_request();
 
-        let mut resp = test::call_service(&mut app, req).await;
+        let mut resp = call_service(&mut app, req).await;
         let body = take_response_body_string(&mut resp).await;
         assert_eq!(resp.status(), http::StatusCode::OK);
         assert_eq!(
@@ -589,7 +592,7 @@ mod tests {
             EmptySubscription::<Database>::new(),
         );
 
-        let req = test::TestRequest::post()
+        let req = TestRequest::post()
             .append_header(("content-type", "application/json; charset=utf-8"))
             .set_payload(
                 r##"{ "variables": null, "query": "{ hero(episode: NEW_HOPE) { name } }" }"##,
@@ -597,14 +600,14 @@ mod tests {
             .uri("/")
             .to_request();
 
-        let mut app = test::init_service(
+        let mut app = init_service(
             App::new()
                 .app_data(Data::new(schema))
                 .route("/", web::post().to(index)),
         )
         .await;
 
-        let mut resp = test::call_service(&mut app, req).await;
+        let mut resp = call_service(&mut app, req).await;
         dbg!(take_response_body_string(&mut resp).await);
         assert_eq!(resp.status(), http::StatusCode::OK);
         assert_eq!(
@@ -625,19 +628,19 @@ mod tests {
             EmptySubscription::<Database>::new(),
         );
 
-        let req = test::TestRequest::get()
+        let req = TestRequest::get()
             .append_header(("content-type", "application/json"))
             .uri("/?query=%7B%20hero%28episode%3A%20NEW_HOPE%29%20%7B%20name%20%7D%20%7D&variables=null")
             .to_request();
 
-        let mut app = test::init_service(
+        let mut app = init_service(
             App::new()
                 .app_data(Data::new(schema))
                 .route("/", web::get().to(index)),
         )
         .await;
 
-        let mut resp = test::call_service(&mut app, req).await;
+        let mut resp = call_service(&mut app, req).await;
 
         assert_eq!(resp.status(), http::StatusCode::OK);
         assert_eq!(
@@ -663,7 +666,7 @@ mod tests {
             EmptySubscription::<Database>::new(),
         );
 
-        let req = test::TestRequest::post()
+        let req = TestRequest::post()
             .append_header(("content-type", "application/json"))
             .set_payload(
                 r##"[
@@ -674,14 +677,14 @@ mod tests {
             .uri("/")
             .to_request();
 
-        let mut app = test::init_service(
+        let mut app = init_service(
             App::new()
                 .app_data(Data::new(schema))
                 .route("/", web::post().to(index)),
         )
         .await;
 
-        let mut resp = test::call_service(&mut app, req).await;
+        let mut resp = call_service(&mut app, req).await;
 
         assert_eq!(resp.status(), http::StatusCode::OK);
         assert_eq!(
@@ -705,7 +708,7 @@ mod tests {
     pub struct TestActixWebIntegration;
 
     impl TestActixWebIntegration {
-        fn make_request(&self, req: test::TestRequest) -> TestResponse {
+        fn make_request(&self, req: TestRequest) -> TestResponse {
             actix_web::rt::System::new().block_on(async move {
                 let schema = Schema::new(
                     Query,
@@ -713,14 +716,14 @@ mod tests {
                     EmptySubscription::<Database>::new(),
                 );
 
-                let mut app = test::init_service(
+                let mut app = init_service(
                     App::new()
                         .app_data(Data::new(schema))
                         .route("/", web::to(index)),
                 )
                 .await;
 
-                let resp = test::call_service(&mut app, req.to_request()).await;
+                let resp = call_service(&mut app, req.to_request()).await;
                 make_test_response(resp).await
             })
         }
@@ -728,12 +731,12 @@ mod tests {
 
     impl HttpIntegration for TestActixWebIntegration {
         fn get(&self, url: &str) -> TestResponse {
-            self.make_request(test::TestRequest::get().uri(url))
+            self.make_request(TestRequest::get().uri(url))
         }
 
         fn post_json(&self, url: &str, body: &str) -> TestResponse {
             self.make_request(
-                test::TestRequest::post()
+                TestRequest::post()
                     .append_header(("content-type", "application/json"))
                     .set_payload(body.to_string())
                     .uri(url),
@@ -742,7 +745,7 @@ mod tests {
 
         fn post_graphql(&self, url: &str, body: &str) -> TestResponse {
             self.make_request(
-                test::TestRequest::post()
+                TestRequest::post()
                     .append_header(("content-type", "application/graphql"))
                     .set_payload(body.to_string())
                     .uri(url),

From acbdf9751480b000fcd44989c1814e8cdf38b2f1 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Mon, 29 Nov 2021 16:11:53 +0300
Subject: [PATCH 04/25] Support FromInputValue for arrays

---
 juniper/src/types/containers.rs | 88 ++++++++++++++++++++++++++-------
 1 file changed, 71 insertions(+), 17 deletions(-)

diff --git a/juniper/src/types/containers.rs b/juniper/src/types/containers.rs
index 9aa542bda..43b1f5490 100644
--- a/juniper/src/types/containers.rs
+++ b/juniper/src/types/containers.rs
@@ -5,7 +5,7 @@ use std::{
 
 use crate::{
     ast::{FromInputValue, InputValue, Selection, ToInputValue},
-    executor::{ExecutionResult, Executor, Registry},
+    executor::{ExecutionResult, Executor, FieldError, IntoFieldError, Registry},
     schema::meta::MetaType,
     types::{
         async_await::GraphQLValueAsync,
@@ -305,12 +305,63 @@ where
     }
 }
 
+/// Error converting [`InputValue`] into exact-size [`array`](prim@array).
+pub enum FromInputValueArrayError<T, S>
+where
+    T: FromInputValue<S>,
+    S: ScalarValue,
+{
+    /// Not enough elements.
+    NotEnough(usize),
+
+    /// Too many elements. Value is [`Vec`] of __all__ [`InputValue`] elements.
+    TooMuch(Vec<S>),
+
+    /// Underlying [`ScalarValue`] conversion error.
+    Scalar(T::Error),
+}
+
+impl<T, S> From<T::Error> for FromInputValueArrayError<T, S>
+where
+    T: FromInputValue<S>,
+    S: ScalarValue,
+{
+    fn from(err: T::Error) -> Self {
+        Self::Scalar(err)
+    }
+}
+
+impl<T, S> IntoFieldError for FromInputValueArrayError<T, S>
+where
+    T: FromInputValue<S>,
+    T::Error: IntoFieldError,
+    S: ScalarValue,
+{
+    fn into_field_error(self) -> FieldError<S> {
+        const ERROR_PREFIX: &str = "Failed to convert into exact-size array";
+
+        match self {
+            Self::NotEnough(len) => FieldError::new(
+                format!("{}: required {} more elements", ERROR_PREFIX, len),
+                graphql_value!(null),
+            ),
+            Self::TooMuch(el) => FieldError::new(
+                format!("{}: too much elements: {}", ERROR_PREFIX, el.len()),
+                graphql_value!(null),
+            ),
+            Self::Scalar(s) => s.into_field_error(),
+        }
+    }
+}
+
 impl<T, S, const N: usize> FromInputValue<S> for [T; N]
 where
     T: FromInputValue<S>,
     S: ScalarValue,
 {
-    fn from_input_value(v: &InputValue<S>) -> Option<Self> {
+    type Error = FromInputValueArrayError<T, S>;
+
+    fn from_input_value(v: &InputValue<S>) -> Result<Self, Self::Error> {
         struct PartiallyInitializedArray<T, const N: usize> {
             arr: [MaybeUninit<T>; N],
             init_len: usize,
@@ -355,20 +406,15 @@ where
                     no_drop: false,
                 };
 
-                let mut items = ls.iter().filter_map(|i| i.item.convert());
-                for elem in &mut out.arr[..] {
-                    if let Some(i) = items.next() {
+                let mut items = ls.iter().map(|i| i.item.convert());
+                for (id, elem) in out.arr.iter_mut().enumerate() {
+                    if let Some(i) = items.next().transpose()? {
                         *elem = MaybeUninit::new(i);
                         out.init_len += 1;
                     } else {
-                        // There is not enough `items` to fill the array.
-                        return None;
+                        return Err(FromInputValueArrayError::NotEnough(N - id));
                     }
                 }
-                if items.next().is_some() {
-                    // There is too much `items` to fit into the array.
-                    return None;
-                }
 
                 // Do not drop collected `items`, because we're going to return
                 // them.
@@ -383,10 +429,18 @@ where
                 //         we won't have a double-free when `T: Drop` here,
                 //         because original array elements are `MaybeUninit`, so
                 //         do nothing on `Drop`.
-                Some(unsafe { mem::transmute_copy::<_, Self>(&out.arr) })
+                let arr = unsafe { mem::transmute_copy::<_, Self>(&out.arr) };
+
+                if !items.is_empty() {
+                    return Err(FromInputValueArrayError::TooMuch(
+                        arr.into_iter().map(Ok).chain(items).collect()?,
+                    ));
+                }
+
+                Ok(arr)
             }
             ref other => {
-                other.convert().and_then(|e: T| {
+                other.convert().map_err(Into::into).and_then(|e: T| {
                     // TODO: Use `mem::transmute` instead of
                     //       `mem::transmute_copy` below, once it's allowed for
                     //       const generics:
@@ -399,11 +453,11 @@ where
                         //         `T: Drop` here, because original `e: T` value
                         //         is wrapped into `mem::ManuallyDrop`, so does
                         //         nothing on `Drop`.
-                        Some(unsafe {
-                            mem::transmute_copy::<_, Self>(&[mem::ManuallyDrop::new(e)])
-                        })
+                        Ok(unsafe { mem::transmute_copy::<_, Self>(&[mem::ManuallyDrop::new(e)]) })
+                    } else if N == 0 {
+                        Err(FromInputValueArrayError::TooMuch(vec![e]))
                     } else {
-                        None
+                        Err(FromInputValueArrayError::NotEnough(N - 1))
                     }
                 })
             }

From 7092bf2d117e0b6d2001d749e5c629e1d2da9325 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Wed, 1 Dec 2021 13:32:50 +0300
Subject: [PATCH 05/25] Fix existing tests

---
 integration_tests/async_await/src/main.rs     |  5 +-
 .../juniper_tests/src/codegen/derive_enum.rs  |  4 +-
 .../src/codegen/derive_input_object.rs        | 10 +-
 .../juniper_tests/src/codegen/impl_scalar.rs  | 53 ++++++----
 .../juniper_tests/src/custom_scalar.rs        | 14 +--
 juniper/src/executor/mod.rs                   |  7 +-
 .../introspection/input_object.rs             |  2 +-
 .../src/executor_tests/introspection/mod.rs   | 11 ++-
 juniper/src/executor_tests/variables.rs       | 16 ++-
 juniper/src/integrations/bson.rs              | 20 +++-
 juniper/src/integrations/chrono.rs            | 49 +++++++---
 juniper/src/integrations/chrono_tz.rs         | 40 +++++---
 juniper/src/integrations/url.rs               |  9 +-
 juniper/src/integrations/uuid.rs              |  9 +-
 juniper/src/lib.rs                            |  2 +-
 juniper/src/macros/helper/mod.rs              | 15 +++
 juniper/src/parser/tests/document.rs          |  5 +-
 juniper/src/schema/meta.rs                    | 17 +++-
 juniper/src/types/base.rs                     |  9 +-
 juniper/src/types/containers.rs               | 98 +++++++++----------
 juniper/src/types/pointers.rs                 |  8 +-
 juniper/src/types/scalars.rs                  | 55 +++++------
 juniper/src/validation/test_harness.rs        | 74 +++++++++-----
 juniper_codegen/src/common/field/arg.rs       | 61 ++++++++++--
 juniper_codegen/src/common/field/mod.rs       | 26 ++---
 juniper_codegen/src/derive_scalar_value.rs    |  8 +-
 juniper_codegen/src/graphql_interface/mod.rs  | 10 +-
 juniper_codegen/src/graphql_object/mod.rs     | 10 +-
 .../src/graphql_subscription/mod.rs           |  4 +-
 juniper_codegen/src/impl_scalar.rs            |  2 +
 juniper_codegen/src/lib.rs                    |  6 +-
 juniper_codegen/src/util/mod.rs               | 37 +++++--
 32 files changed, 451 insertions(+), 245 deletions(-)

diff --git a/integration_tests/async_await/src/main.rs b/integration_tests/async_await/src/main.rs
index ce185ba8c..cf58f90f0 100644
--- a/integration_tests/async_await/src/main.rs
+++ b/integration_tests/async_await/src/main.rs
@@ -1,4 +1,7 @@
-use juniper::{graphql_object, GraphQLEnum};
+use juniper::{
+    graphql_object, graphql_value, EmptyMutation, EmptySubscription, GraphQLEnum, GraphQLError,
+    RootNode, Value,
+};
 
 #[derive(GraphQLEnum)]
 enum UserKind {
diff --git a/integration_tests/juniper_tests/src/codegen/derive_enum.rs b/integration_tests/juniper_tests/src/codegen/derive_enum.rs
index 45e90c9be..e3b5c7699 100644
--- a/integration_tests/juniper_tests/src/codegen/derive_enum.rs
+++ b/integration_tests/juniper_tests/src/codegen/derive_enum.rs
@@ -84,7 +84,7 @@ fn test_derived_enum() {
     );
     assert_eq!(
         FromInputValue::<DefaultScalarValue>::from_input_value(&graphql_input_value!(REGULAR)),
-        Some(SomeEnum::Regular),
+        Ok(SomeEnum::Regular),
     );
 
     // Test FULL variant.
@@ -94,7 +94,7 @@ fn test_derived_enum() {
     );
     assert_eq!(
         FromInputValue::<DefaultScalarValue>::from_input_value(&graphql_input_value!(FULL)),
-        Some(SomeEnum::Full)
+        Ok(SomeEnum::Full)
     );
 }
 
diff --git a/integration_tests/juniper_tests/src/codegen/derive_input_object.rs b/integration_tests/juniper_tests/src/codegen/derive_input_object.rs
index 90b283452..fc9065fa1 100644
--- a/integration_tests/juniper_tests/src/codegen/derive_input_object.rs
+++ b/integration_tests/juniper_tests/src/codegen/derive_input_object.rs
@@ -1,7 +1,7 @@
 use fnv::FnvHashMap;
 use juniper::{
-    graphql_input_value, marker, DefaultScalarValue, FromInputValue, GraphQLInputObject,
-    GraphQLType, GraphQLValue, InputValue, Registry, ToInputValue,
+    graphql_input_value, marker, DefaultScalarValue, FieldError, FromInputValue,
+    GraphQLInputObject, GraphQLType, GraphQLValue, InputValue, Registry, ToInputValue,
 };
 
 #[derive(GraphQLInputObject, Debug, PartialEq)]
@@ -58,8 +58,10 @@ struct Fake;
 impl<'a> marker::IsInputType<DefaultScalarValue> for &'a Fake {}
 
 impl<'a> FromInputValue for &'a Fake {
-    fn from_input_value(_v: &InputValue) -> Option<&'a Fake> {
-        None
+    type Error = FieldError;
+
+    fn from_input_value(_v: &InputValue) -> Result<&'a Fake, Self::Error> {
+        Err(FieldError::from("This is fake"))
     }
 }
 
diff --git a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
index 3432c2f6a..4c036b53d 100644
--- a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
+++ b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
@@ -1,6 +1,7 @@
 use juniper::{
     execute, graphql_object, graphql_scalar, graphql_value, graphql_vars, DefaultScalarValue,
-    EmptyMutation, EmptySubscription, Object, ParseScalarResult, ParseScalarValue, RootNode, Value,
+    EmptyMutation, EmptySubscription, FieldError, Object, ParseScalarResult, ParseScalarValue,
+    RootNode, Value,
 };
 
 use crate::custom_scalar::MyScalarValue;
@@ -31,10 +32,11 @@ where
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<DefaultName> {
-        v.as_scalar_value()
-            .and_then(|s| s.as_int())
-            .map(|i| DefaultName(i))
+    fn from_input_value(v: &InputValue) -> Result<DefaultName, FieldError> {
+        v.as_int_value()
+            .map(DefaultName)
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -48,8 +50,11 @@ impl GraphQLScalar for OtherOrder {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<OtherOrder> {
-        v.as_scalar_value::<i32>().map(|i| OtherOrder(*i))
+    fn from_input_value(v: &InputValue) -> Result<OtherOrder, FieldError> {
+        v.as_int_value()
+            .map(OtherOrder)
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -63,8 +68,11 @@ impl GraphQLScalar for Named {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<Named> {
-        v.as_scalar_value::<i32>().map(|i| Named(*i))
+    fn from_input_value(v: &InputValue) -> Result<Named, FieldError> {
+        v.as_int_value()
+            .map(Named)
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -78,8 +86,11 @@ impl GraphQLScalar for ScalarDescription {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<ScalarDescription> {
-        v.as_scalar_value::<i32>().map(|i| ScalarDescription(*i))
+    fn from_input_value(v: &InputValue) -> Result<ScalarDescription, FieldError> {
+        v.as_int_value()
+            .map(ScalarDescription)
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -98,10 +109,11 @@ macro_rules! impl_scalar {
                 Value::scalar(self.0.clone())
             }
 
-            fn from_input_value(v: &InputValue) -> Option<Self> {
+            fn from_input_value(v: &InputValue) -> Result<Self, FieldError<S>> {
                 v.as_scalar_value()
                     .and_then(|v| v.as_str())
                     .and_then(|s| Some(Self(s.to_owned())))
+                    .ok_or_else(|| "Expected String".into())
             }
 
             fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -140,9 +152,13 @@ impl GraphQLScalar for WithCustomScalarValue {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue<MyScalarValue>) -> Option<WithCustomScalarValue> {
-        v.as_scalar_value::<i32>()
-            .map(|i| WithCustomScalarValue(*i))
+    fn from_input_value(
+        v: &InputValue<MyScalarValue>,
+    ) -> Result<WithCustomScalarValue, FieldError<MyScalarValue>> {
+        v.as_int_value()
+            .map(WithCustomScalarValue)
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, MyScalarValue> {
@@ -198,8 +214,11 @@ fn path_in_resolve_return_type() {
             Value::scalar(self.0)
         }
 
-        fn from_input_value(v: &InputValue) -> Option<ResolvePath> {
-            v.as_scalar_value::<i32>().map(|i| ResolvePath(*i))
+        fn from_input_value(v: &InputValue) -> Result<ResolvePath, FieldError> {
+            v.as_int_value()
+                .map(ResolvePath)
+                .ok_or_else(|| format!("Expected Int, found: {}", v))
+                .map_err(Into::into)
         }
 
         fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
diff --git a/integration_tests/juniper_tests/src/custom_scalar.rs b/integration_tests/juniper_tests/src/custom_scalar.rs
index 64fe39980..a2c12bbac 100644
--- a/integration_tests/juniper_tests/src/custom_scalar.rs
+++ b/integration_tests/juniper_tests/src/custom_scalar.rs
@@ -6,8 +6,8 @@ use juniper::{
     graphql_vars,
     parser::{ParseError, ScalarToken, Token},
     serde::{de, Deserialize, Deserializer, Serialize},
-    EmptyMutation, FieldResult, GraphQLScalarValue, InputValue, Object, ParseScalarResult,
-    RootNode, ScalarValue, Value, Variables,
+    EmptyMutation, FieldError, FieldResult, GraphQLScalarValue, InputValue, Object,
+    ParseScalarResult, RootNode, ScalarValue, Value, Variables,
 };
 
 #[derive(GraphQLScalarValue, Clone, Debug, PartialEq, Serialize)]
@@ -138,11 +138,11 @@ impl GraphQLScalar for i64 {
         Value::scalar(*self)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<i64> {
-        match *v {
-            InputValue::Scalar(MyScalarValue::Long(i)) => Some(i),
-            _ => None,
-        }
+    fn from_input_value(v: &InputValue) -> Result<i64, FieldError> {
+        v.as_scalar_value::<i64>()
+            .copied()
+            .ok_or_else(|| format!("Expected MyScalarValue::Long(), found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, MyScalarValue> {
diff --git a/juniper/src/executor/mod.rs b/juniper/src/executor/mod.rs
index 719ce7abc..2bda95b2d 100644
--- a/juniper/src/executor/mod.rs
+++ b/juniper/src/executor/mod.rs
@@ -151,8 +151,11 @@ where
 /// ```
 #[derive(Clone, Debug, PartialEq)]
 pub struct FieldError<S = DefaultScalarValue> {
-    message: String,
-    extensions: Value<S>,
+    /// Error message.
+    pub message: String,
+
+    /// [`Value`] containing additional information.
+    pub extensions: Value<S>,
 }
 
 impl<T: Display, S> From<T> for FieldError<S> {
diff --git a/juniper/src/executor_tests/introspection/input_object.rs b/juniper/src/executor_tests/introspection/input_object.rs
index b3451463c..d433681a5 100644
--- a/juniper/src/executor_tests/introspection/input_object.rs
+++ b/juniper/src/executor_tests/introspection/input_object.rs
@@ -206,7 +206,7 @@ fn default_name_input_value() {
 
     let dv = DefaultName::from_input_value(&iv);
 
-    assert!(dv.is_ok(), "error: {}", dv.unwrap_err());
+    assert!(dv.is_ok(), "error: {:?}", dv.unwrap_err());
 
     let dv = dv.unwrap();
 
diff --git a/juniper/src/executor_tests/introspection/mod.rs b/juniper/src/executor_tests/introspection/mod.rs
index 5778d8cb6..b02d7c2f8 100644
--- a/juniper/src/executor_tests/introspection/mod.rs
+++ b/juniper/src/executor_tests/introspection/mod.rs
@@ -9,8 +9,8 @@ use crate::{
     graphql_interface, graphql_object, graphql_scalar, graphql_value, graphql_vars,
     schema::model::RootNode,
     types::scalars::{EmptyMutation, EmptySubscription},
-    value::{ParseScalarResult, ParseScalarValue, ScalarValue, Value},
-    GraphQLEnum,
+    value::{ParseScalarResult, ParseScalarValue, Value},
+    FieldError, GraphQLEnum,
 };
 
 #[derive(GraphQLEnum)]
@@ -28,8 +28,11 @@ impl<S: ScalarValue> GraphQLScalar for Scalar {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<Scalar> {
-        v.as_scalar().and_then(ScalarValue::as_int).map(Scalar)
+    fn from_input_value(v: &InputValue) -> Result<Scalar, FieldError> {
+        v.as_int_value()
+            .map(Scalar)
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/executor_tests/variables.rs b/juniper/src/executor_tests/variables.rs
index d4266e0f5..be895dc95 100644
--- a/juniper/src/executor_tests/variables.rs
+++ b/juniper/src/executor_tests/variables.rs
@@ -5,7 +5,8 @@ use crate::{
     schema::model::RootNode,
     types::scalars::{EmptyMutation, EmptySubscription},
     validation::RuleError,
-    value::{DefaultScalarValue, Object, ParseScalarResult, ParseScalarValue, ScalarValue},
+    value::{DefaultScalarValue, Object, ParseScalarResult, ParseScalarValue},
+    FieldError,
     GraphQLError::ValidationError,
     GraphQLInputObject,
 };
@@ -19,14 +20,11 @@ impl<S: ScalarValue> GraphQLScalar for TestComplexScalar {
         graphql_value!("SerializedValue")
     }
 
-    fn from_input_value(v: &InputValue) -> Option<TestComplexScalar> {
-        if let Some(s) = v.as_scalar().and_then(ScalarValue::as_str) {
-            if s == "SerializedValue" {
-                return Some(TestComplexScalar);
-            }
-        }
-
-        None
+    fn from_input_value(v: &InputValue) -> Result<TestComplexScalar, FieldError> {
+        v.as_string_value()
+            .filter(|s| *s == "SerializedValue")
+            .map(|_| TestComplexScalar)
+            .ok_or_else(|| format!("Expected SerializedValue String, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/integrations/bson.rs b/juniper/src/integrations/bson.rs
index 4dd38dfc9..ee502c1f7 100644
--- a/juniper/src/integrations/bson.rs
+++ b/juniper/src/integrations/bson.rs
@@ -7,7 +7,7 @@ use crate::{
     graphql_scalar,
     parser::{ParseError, ScalarToken, Token},
     value::ParseScalarResult,
-    Value,
+    FieldError, Value,
 };
 
 #[graphql_scalar(description = "ObjectId")]
@@ -19,8 +19,13 @@ where
         Value::scalar(self.to_hex())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<ObjectId> {
-        v.as_string_value().and_then(|s| Self::parse_str(s).ok())
+    fn from_input_value(v: &InputValue) -> Result<ObjectId, FieldError> {
+        v.as_string_value()
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .and_then(|s| {
+                Self::parse_str(s).map_err(|e| format!("Failed to parse UtcDateTime: {}", e))
+            })
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -41,10 +46,15 @@ where
         Value::scalar((*self).to_chrono().to_rfc3339())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<UtcDateTime> {
+    fn from_input_value(v: &InputValue) -> Result<UtcDateTime, FieldError> {
         v.as_string_value()
-            .and_then(|s| (s.parse::<DateTime<Utc>>().ok()))
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .and_then(|s| {
+                s.parse::<DateTime<Utc>>()
+                    .map_err(|e| format!("Failed to parse UtcDateTime: {}", e))
+            })
             .map(Self::from_chrono)
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/integrations/chrono.rs b/juniper/src/integrations/chrono.rs
index eb8fcbb42..e20d1262c 100644
--- a/juniper/src/integrations/chrono.rs
+++ b/juniper/src/integrations/chrono.rs
@@ -21,7 +21,7 @@ use chrono::prelude::*;
 use crate::{
     parser::{ParseError, ScalarToken, Token},
     value::{ParseScalarResult, ParseScalarValue},
-    Value,
+    FieldError, Value,
 };
 
 #[doc(hidden)]
@@ -36,9 +36,13 @@ where
         Value::scalar(self.to_rfc3339())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<DateTime<FixedOffset>> {
-        v.as_string_value()
-            .and_then(|s| DateTime::parse_from_rfc3339(s).ok())
+    fn from_input_value(v: &InputValue) -> Result<DateTime<FixedOffset>, FieldError> {
+        Ok(v.as_string_value()
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .and_then(|s| {
+                DateTime::parse_from_rfc3339(s)
+                    .map_err(|e| format!("Failed to parse DateTimeFixedOffset: {}", e))
+            })?)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -59,9 +63,14 @@ where
         Value::scalar(self.to_rfc3339())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<DateTime<Utc>> {
+    fn from_input_value(v: &InputValue) -> Result<DateTime<Utc>, FieldError> {
         v.as_string_value()
-            .and_then(|s| (s.parse::<DateTime<Utc>>().ok()))
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .and_then(|s| {
+                s.parse::<DateTime<Utc>>()
+                    .map_err(|e| format!("Failed to parse DateTime: {}", e))
+            })
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -87,9 +96,14 @@ where
         Value::scalar(self.format("%Y-%m-%d").to_string())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<NaiveDate> {
+    fn from_input_value(v: &InputValue) -> Result<NaiveDate, FieldError> {
         v.as_string_value()
-            .and_then(|s| NaiveDate::parse_from_str(s, "%Y-%m-%d").ok())
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .and_then(|s| {
+                NaiveDate::parse_from_str(s, "%Y-%m-%d")
+                    .map_err(|e| format!("Failed to parse NaiveDate: {}", e))
+            })
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -111,9 +125,14 @@ where
         Value::scalar(self.format("%H:%M:%S").to_string())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<NaiveTime> {
+    fn from_input_value(v: &InputValue) -> Result<NaiveTime, FieldError> {
         v.as_string_value()
-            .and_then(|s| NaiveTime::parse_from_str(s, "%H:%M:%S").ok())
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .and_then(|s| {
+                NaiveTime::parse_from_str(s, "%H:%M:%S")
+                    .map_err(|e| format!("Failed to parse NaiveTime: {}", e))
+            })
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -136,9 +155,15 @@ where
         Value::scalar(self.timestamp() as f64)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<NaiveDateTime> {
+    fn from_input_value(v: &InputValue) -> Result<NaiveDateTime, FieldError> {
         v.as_float_value()
-            .and_then(|f| NaiveDateTime::from_timestamp_opt(f as i64, 0))
+            .ok_or_else(|| format!("Expected Float, found: {}", v))
+            .and_then(|f| {
+                let secs = f as i64;
+                NaiveDateTime::from_timestamp_opt(secs, 0)
+                    .ok_or_else(|| format!("Out-of-range number of seconds: {}", secs))
+            })
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/integrations/chrono_tz.rs b/juniper/src/integrations/chrono_tz.rs
index 14963e83b..c7f383a01 100644
--- a/juniper/src/integrations/chrono_tz.rs
+++ b/juniper/src/integrations/chrono_tz.rs
@@ -9,7 +9,7 @@ use crate::{
     graphql_scalar,
     parser::{ParseError, ScalarToken, Token},
     value::ParseScalarResult,
-    Value,
+    FieldError, Value,
 };
 
 #[graphql_scalar(name = "Tz", description = "Timezone")]
@@ -21,8 +21,14 @@ where
         Value::scalar(self.name().to_owned())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<Tz> {
-        v.as_string_value().and_then(|s| s.parse::<Tz>().ok())
+    fn from_input_value(v: &InputValue) -> Result<Tz, FieldError> {
+        v.as_string_value()
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .and_then(|s| {
+                s.parse::<Tz>()
+                    .map_err(|e| format!("Failed to parse Timezone: {}", e))
+            })
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(val: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -39,23 +45,24 @@ mod test {
     mod from_input_value {
         use chrono_tz::Tz;
 
-        use crate::{graphql_input_value, FromInputValue, InputValue};
+        use crate::{graphql_input_value, FieldError, FromInputValue, InputValue};
 
-        fn tz_input_test(raw: &'static str, expected: Option<Tz>) {
+        fn tz_input_test(raw: &'static str, expected: Result<Tz, &str>) {
             let input: InputValue = graphql_input_value!((raw));
-            let parsed: Option<Tz> = FromInputValue::from_input_value(&input);
+            let parsed =
+                FromInputValue::from_input_value(&input).map_err(|e: FieldError| e.message);
 
-            assert_eq!(parsed, expected);
+            assert_eq!(parsed, expected.map_err(str::to_owned));
         }
 
         #[test]
         fn europe_zone() {
-            tz_input_test("Europe/London", Some(chrono_tz::Europe::London));
+            tz_input_test("Europe/London", Ok(chrono_tz::Europe::London));
         }
 
         #[test]
         fn etc_minus() {
-            tz_input_test("Etc/GMT-3", Some(chrono_tz::Etc::GMTMinus3));
+            tz_input_test("Etc/GMT-3", Ok(chrono_tz::Etc::GMTMinus3));
         }
 
         mod invalid {
@@ -63,17 +70,26 @@ mod test {
 
             #[test]
             fn forward_slash() {
-                tz_input_test("Abc/Xyz", None);
+                tz_input_test(
+                    "Abc/Xyz",
+                    Err("Failed to parse Timezone: received invalid timezone"),
+                );
             }
 
             #[test]
             fn number() {
-                tz_input_test("8086", None);
+                tz_input_test(
+                    "8086",
+                    Err("Failed to parse Timezone: received invalid timezone"),
+                );
             }
 
             #[test]
             fn no_forward_slash() {
-                tz_input_test("AbcXyz", None);
+                tz_input_test(
+                    "AbcXyz",
+                    Err("Failed to parse Timezone: received invalid timezone"),
+                );
             }
         }
     }
diff --git a/juniper/src/integrations/url.rs b/juniper/src/integrations/url.rs
index 659cba1f2..b3ae25196 100644
--- a/juniper/src/integrations/url.rs
+++ b/juniper/src/integrations/url.rs
@@ -4,7 +4,7 @@ use url::Url;
 
 use crate::{
     value::{ParseScalarResult, ParseScalarValue},
-    Value,
+    FieldError, Value,
 };
 
 #[crate::graphql_scalar(description = "Url")]
@@ -16,8 +16,11 @@ where
         Value::scalar(self.as_str().to_owned())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<Url> {
-        v.as_string_value().and_then(|s| Url::parse(s).ok())
+    fn from_input_value(v: &InputValue) -> Result<Url, FieldError> {
+        v.as_string_value()
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .and_then(|s| Url::parse(s).map_err(|e| format!("Failed to parse Url: {}", e)))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/integrations/uuid.rs b/juniper/src/integrations/uuid.rs
index 43f716b6f..5dfa7a7bb 100644
--- a/juniper/src/integrations/uuid.rs
+++ b/juniper/src/integrations/uuid.rs
@@ -7,7 +7,7 @@ use uuid::Uuid;
 use crate::{
     parser::{ParseError, ScalarToken, Token},
     value::ParseScalarResult,
-    Value,
+    FieldError, Value,
 };
 
 #[crate::graphql_scalar(description = "Uuid")]
@@ -19,8 +19,11 @@ where
         Value::scalar(self.to_string())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<Uuid> {
-        v.as_string_value().and_then(|s| Uuid::parse_str(s).ok())
+    fn from_input_value(v: &InputValue) -> Result<Uuid, FieldError> {
+        v.as_string_value()
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .and_then(|s| Uuid::parse_str(s).map_err(|e| format!("Failed to parse Uuid: {}", e)))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/lib.rs b/juniper/src/lib.rs
index d17f1b399..365261e2e 100644
--- a/juniper/src/lib.rs
+++ b/juniper/src/lib.rs
@@ -163,7 +163,7 @@ pub use crate::{
     introspection::IntrospectionFormat,
     macros::helper::{
         subscription::{ExtractTypeFromStream, IntoFieldResult},
-        AsDynGraphQLValue,
+        AsDynGraphQLValue, ExtractErrorFromResult,
     },
     parser::{ParseError, Spanning},
     schema::{
diff --git a/juniper/src/macros/helper/mod.rs b/juniper/src/macros/helper/mod.rs
index 8162b7a9c..01caaf562 100644
--- a/juniper/src/macros/helper/mod.rs
+++ b/juniper/src/macros/helper/mod.rs
@@ -32,3 +32,18 @@ pub trait AsDynGraphQLValue<S: ScalarValue = DefaultScalarValue> {
 }
 
 crate::sa::assert_obj_safe!(AsDynGraphQLValue<Context = (), TypeInfo = ()>);
+
+/// This trait is used in `juniper::graphql_scalar` macro to [`Result`]s
+/// [`Error`].
+///
+/// [`Error`]: Result::Error
+pub trait ExtractErrorFromResult {
+    /// [`Result`]s [`Error`].
+    ///
+    /// [`Error`]: Result::Error
+    type Error;
+}
+
+impl<T, E> ExtractErrorFromResult for Result<T, E> {
+    type Error = E;
+}
diff --git a/juniper/src/parser/tests/document.rs b/juniper/src/parser/tests/document.rs
index 29959265f..bb28074b0 100644
--- a/juniper/src/parser/tests/document.rs
+++ b/juniper/src/parser/tests/document.rs
@@ -1,8 +1,5 @@
 use crate::{
-    ast::{
-        Arguments, Definition, Field, InputValue, Operation, OperationType, OwnedDocument,
-        Selection,
-    },
+    ast::{Arguments, Definition, Field, Operation, OperationType, OwnedDocument, Selection},
     graphql_input_value,
     parser::{document::parse_document_source, ParseError, SourcePosition, Spanning, Token},
     schema::model::SchemaType,
diff --git a/juniper/src/schema/meta.rs b/juniper/src/schema/meta.rs
index e7f4e8cf6..c20e21e52 100644
--- a/juniper/src/schema/meta.rs
+++ b/juniper/src/schema/meta.rs
@@ -10,7 +10,7 @@ use crate::{
     parser::{ParseError, ScalarToken},
     schema::model::SchemaType,
     types::base::TypeKind,
-    value::{DefaultScalarValue, ParseScalarValue, ScalarValue},
+    value::{DefaultScalarValue, ParseScalarValue},
 };
 
 /// Whether an item is deprecated, with context.
@@ -467,7 +467,10 @@ impl<'a> NullableMeta<'a> {
 
 impl<'a, S> ObjectMeta<'a, S> {
     /// Build a new [`ObjectMeta`] type with the specified `name` and `fields`.
-    pub fn new(name: Cow<'a, str>, fields: &[Field<'a, S>]) -> Self {
+    pub fn new(name: Cow<'a, str>, fields: &[Field<'a, S>]) -> Self
+    where
+        S: Clone,
+    {
         Self {
             name,
             description: None,
@@ -533,11 +536,14 @@ impl<'a, S> EnumMeta<'a, S> {
 impl<'a, S> InterfaceMeta<'a, S> {
     /// Builds a new [`InterfaceMeta`] type with the specified `name` and
     /// `fields`.
-    pub fn new(name: Cow<'a, str>, fields: &[Field<'a, S>]) -> Self {
+    pub fn new(name: Cow<'a, str>, fields: &[Field<'a, S>]) -> Self
+    where
+        S: Clone,
+    {
         Self {
             name,
             description: None,
-            fields: fields.to_owned(),
+            fields: fields.to_vec(),
         }
     }
 
@@ -589,11 +595,12 @@ impl<'a, S> InputObjectMeta<'a, S> {
     pub fn new<T>(name: Cow<'a, str>, input_fields: &[Argument<'a, S>]) -> Self
     where
         T: FromInputValue<S>,
+        S: Clone,
     {
         Self {
             name,
             description: None,
-            input_fields: input_fields.to_owned(),
+            input_fields: input_fields.to_vec(),
             try_parse_fn: try_parse_fn::<S, T>,
         }
     }
diff --git a/juniper/src/types/base.rs b/juniper/src/types/base.rs
index e06d5e943..175be9293 100644
--- a/juniper/src/types/base.rs
+++ b/juniper/src/types/base.rs
@@ -6,7 +6,7 @@ use crate::{
     parser::Spanning,
     schema::meta::{Argument, MetaType},
     value::{DefaultScalarValue, Object, ScalarValue, Value},
-    GraphQLEnum, IntoFieldError, FieldResult
+    FieldResult, GraphQLEnum, IntoFieldError,
 };
 
 /// GraphQL type kind
@@ -78,7 +78,10 @@ impl<'a, S> Arguments<'a, S> {
     pub fn new(
         mut args: Option<IndexMap<&'a str, InputValue<S>>>,
         meta_args: &'a Option<Vec<Argument<S>>>,
-    ) -> Self {
+    ) -> Self
+    where
+        S: Clone,
+    {
         if meta_args.is_some() && args.is_none() {
             args = Some(IndexMap::new());
         }
@@ -87,7 +90,7 @@ impl<'a, S> Arguments<'a, S> {
             for arg in meta_args {
                 let arg_name = arg.name.as_str();
                 if args.get(arg_name).map_or(true, InputValue::is_null) {
-                    if let Some(val) = &arg.default_value {
+                    if let Some(val) = arg.default_value.as_ref() {
                         args.insert(arg_name, val.clone());
                     }
                 }
diff --git a/juniper/src/types/containers.rs b/juniper/src/types/containers.rs
index 43b1f5490..053219a4d 100644
--- a/juniper/src/types/containers.rs
+++ b/juniper/src/types/containers.rs
@@ -1,4 +1,5 @@
 use std::{
+    array,
     mem::{self, MaybeUninit},
     ptr,
 };
@@ -315,40 +316,28 @@ where
     NotEnough(usize),
 
     /// Too many elements. Value is [`Vec`] of __all__ [`InputValue`] elements.
-    TooMuch(Vec<S>),
+    TooMuch(Vec<T>),
 
     /// Underlying [`ScalarValue`] conversion error.
     Scalar(T::Error),
 }
 
-impl<T, S> From<T::Error> for FromInputValueArrayError<T, S>
+impl<T, S> IntoFieldError<S> for FromInputValueArrayError<T, S>
 where
     T: FromInputValue<S>,
-    S: ScalarValue,
-{
-    fn from(err: T::Error) -> Self {
-        Self::Scalar(err)
-    }
-}
-
-impl<T, S> IntoFieldError for FromInputValueArrayError<T, S>
-where
-    T: FromInputValue<S>,
-    T::Error: IntoFieldError,
+    T::Error: IntoFieldError<S>,
     S: ScalarValue,
 {
     fn into_field_error(self) -> FieldError<S> {
         const ERROR_PREFIX: &str = "Failed to convert into exact-size array";
 
         match self {
-            Self::NotEnough(len) => FieldError::new(
-                format!("{}: required {} more elements", ERROR_PREFIX, len),
-                graphql_value!(null),
-            ),
-            Self::TooMuch(el) => FieldError::new(
-                format!("{}: too much elements: {}", ERROR_PREFIX, el.len()),
-                graphql_value!(null),
-            ),
+            Self::NotEnough(len) => {
+                FieldError::<S>::from(format!("{}: required {} more elements", ERROR_PREFIX, len))
+            }
+            Self::TooMuch(el) => {
+                FieldError::<S>::from(format!("{}: too much elements: {}", ERROR_PREFIX, el.len()))
+            }
             Self::Scalar(s) => s.into_field_error(),
         }
     }
@@ -408,7 +397,11 @@ where
 
                 let mut items = ls.iter().map(|i| i.item.convert());
                 for (id, elem) in out.arr.iter_mut().enumerate() {
-                    if let Some(i) = items.next().transpose()? {
+                    if let Some(i) = items
+                        .next()
+                        .transpose()
+                        .map_err(FromInputValueArrayError::Scalar)?
+                    {
                         *elem = MaybeUninit::new(i);
                         out.init_len += 1;
                     } else {
@@ -431,35 +424,44 @@ where
                 //         do nothing on `Drop`.
                 let arr = unsafe { mem::transmute_copy::<_, Self>(&out.arr) };
 
-                if !items.is_empty() {
+                if items.len() > 0 {
                     return Err(FromInputValueArrayError::TooMuch(
-                        arr.into_iter().map(Ok).chain(items).collect()?,
+                        array::IntoIter::new(arr)
+                            .map(Ok)
+                            .chain(items)
+                            .collect::<Result<_, _>>()
+                            .map_err(FromInputValueArrayError::Scalar)?,
                     ));
                 }
 
                 Ok(arr)
             }
             ref other => {
-                other.convert().map_err(Into::into).and_then(|e: T| {
-                    // TODO: Use `mem::transmute` instead of
-                    //       `mem::transmute_copy` below, once it's allowed for
-                    //       const generics:
-                    //       https://github.com/rust-lang/rust/issues/61956
-                    if N == 1 {
-                        // SAFETY: `mem::transmute_copy` is safe here, because
-                        //         we check `N` to be `1`.
-                        //         Also, despite `mem::transmute_copy` copies
-                        //         the value, we won't have a double-free when
-                        //         `T: Drop` here, because original `e: T` value
-                        //         is wrapped into `mem::ManuallyDrop`, so does
-                        //         nothing on `Drop`.
-                        Ok(unsafe { mem::transmute_copy::<_, Self>(&[mem::ManuallyDrop::new(e)]) })
-                    } else if N == 0 {
-                        Err(FromInputValueArrayError::TooMuch(vec![e]))
-                    } else {
-                        Err(FromInputValueArrayError::NotEnough(N - 1))
-                    }
-                })
+                other
+                    .convert()
+                    .map_err(FromInputValueArrayError::Scalar)
+                    .and_then(|e: T| {
+                        // TODO: Use `mem::transmute` instead of
+                        //       `mem::transmute_copy` below, once it's allowed for
+                        //       const generics:
+                        //       https://github.com/rust-lang/rust/issues/61956
+                        if N == 1 {
+                            // SAFETY: `mem::transmute_copy` is safe here, because
+                            //         we check `N` to be `1`.
+                            //         Also, despite `mem::transmute_copy` copies
+                            //         the value, we won't have a double-free when
+                            //         `T: Drop` here, because original `e: T` value
+                            //         is wrapped into `mem::ManuallyDrop`, so does
+                            //         nothing on `Drop`.
+                            Ok(unsafe {
+                                mem::transmute_copy::<_, Self>(&[mem::ManuallyDrop::new(e)])
+                            })
+                        } else if N == 0 {
+                            Err(FromInputValueArrayError::TooMuch(vec![e]))
+                        } else {
+                            Err(FromInputValueArrayError::NotEnough(N - 1))
+                        }
+                    })
             }
         }
     }
@@ -543,16 +545,14 @@ where
 mod coercion {
     use crate::{FromInputValue as _, InputValue};
 
+    type V = InputValue;
+
     // See "Input Coercion" examples on List types:
     // https://spec.graphql.org/June2018/#sec-Type-System.List
     #[test]
     fn vec() {
         assert_eq!(
-            <Vec<i32>>::from_input_value(&InputValue::list(vec![
-                InputValue::scalar(1),
-                InputValue::scalar(2),
-                InputValue::scalar(3)
-            ])),
+            <Vec<i32>>::from_input_value(&V::list(vec![V::scalar(1), V::scalar(2), V::scalar(3)])),
             Ok(vec![1, 2, 3]),
         );
         // TODO: all examples
diff --git a/juniper/src/types/pointers.rs b/juniper/src/types/pointers.rs
index 857209229..0726ef525 100644
--- a/juniper/src/types/pointers.rs
+++ b/juniper/src/types/pointers.rs
@@ -93,7 +93,9 @@ where
     S: ScalarValue,
     T: FromInputValue<S>,
 {
-    fn from_input_value(v: &InputValue<S>) -> Option<Box<T>> {
+    type Error = T::Error;
+
+    fn from_input_value(v: &InputValue<S>) -> Result<Box<T>, Self::Error> {
         <T as FromInputValue<S>>::from_input_value(v).map(Box::new)
     }
 }
@@ -285,7 +287,9 @@ where
     S: ScalarValue,
     T: FromInputValue<S>,
 {
-    fn from_input_value(v: &InputValue<S>) -> Option<Arc<T>> {
+    type Error = T::Error;
+
+    fn from_input_value(v: &InputValue<S>) -> Result<Arc<T>, Self::Error> {
         <T as FromInputValue<S>>::from_input_value(v).map(Arc::new)
     }
 }
diff --git a/juniper/src/types/scalars.rs b/juniper/src/types/scalars.rs
index 3ebac39c6..a5c6eee35 100644
--- a/juniper/src/types/scalars.rs
+++ b/juniper/src/types/scalars.rs
@@ -6,7 +6,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::{
     ast::{InputValue, Selection, ToInputValue},
-    executor::{ExecutionResult, Executor, Registry},
+    executor::{ExecutionResult, Executor, FieldError, Registry},
     parser::{LexerError, ParseError, ScalarToken, Token},
     schema::meta::MetaType,
     types::{
@@ -59,14 +59,13 @@ where
         Value::scalar(self.0.clone())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<ID> {
-        match *v {
-            InputValue::Scalar(ref s) => s
-                .as_string()
-                .or_else(|| s.as_int().map(|i| i.to_string()))
-                .map(ID),
-            _ => None,
-        }
+    fn from_input_value(v: &InputValue) -> Result<ID, FieldError> {
+        v.as_string_value()
+            .map(str::to_owned)
+            .or_else(|| v.as_int_value().map(|i| i.to_string()))
+            .ok_or_else(|| format!("Expected String or Int, found: {}", v))
+            .map(ID)
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -86,11 +85,11 @@ where
         Value::scalar(self.clone())
     }
 
-    fn from_input_value(v: &InputValue) -> Option<String> {
-        match *v {
-            InputValue::Scalar(ref s) => s.as_string(),
-            _ => None,
-        }
+    fn from_input_value(v: &InputValue) -> Result<String, FieldError> {
+        v.as_string_value()
+            .map(str::to_owned)
+            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -275,11 +274,11 @@ where
         Value::scalar(*self)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<bool> {
-        match *v {
-            InputValue::Scalar(ref b) => b.as_boolean(),
-            _ => None,
-        }
+    fn from_input_value(v: &InputValue) -> Result<bool, FieldError> {
+        v.as_scalar_value()
+            .and_then(ScalarValue::as_boolean)
+            .ok_or_else(|| format!("Expected Boolean, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -297,11 +296,10 @@ where
         Value::scalar(*self)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<i32> {
-        match *v {
-            InputValue::Scalar(ref i) => i.as_int(),
-            _ => None,
-        }
+    fn from_input_value(v: &InputValue) -> Result<i32, FieldError> {
+        v.as_int_value()
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -324,11 +322,10 @@ where
         Value::scalar(*self)
     }
 
-    fn from_input_value(v: &InputValue) -> Option<f64> {
-        match *v {
-            InputValue::Scalar(ref s) => s.as_float(),
-            _ => None,
-        }
+    fn from_input_value(v: &InputValue) -> Result<f64, FieldError> {
+        v.as_float_value()
+            .ok_or_else(|| format!("Expected Float, found: {}", v))
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/validation/test_harness.rs b/juniper/src/validation/test_harness.rs
index 7bd75f7b0..e626a2ce5 100644
--- a/juniper/src/validation/test_harness.rs
+++ b/juniper/src/validation/test_harness.rs
@@ -2,7 +2,7 @@ use std::mem;
 
 use crate::{
     ast::{FromInputValue, InputValue},
-    executor::Registry,
+    executor::{FieldError, Registry},
     parser::parse_document_source,
     schema::{
         meta::{EnumValue, MetaType},
@@ -208,12 +208,14 @@ impl<S> FromInputValue<S> for DogCommand
 where
     S: ScalarValue,
 {
-    fn from_input_value<'a>(v: &InputValue<S>) -> Option<DogCommand> {
+    type Error = FieldError<S>;
+
+    fn from_input_value<'a>(v: &InputValue<S>) -> Result<DogCommand, Self::Error> {
         match v.as_enum_value() {
-            Some("SIT") => Some(DogCommand::Sit),
-            Some("HEEL") => Some(DogCommand::Heel),
-            Some("DOWN") => Some(DogCommand::Down),
-            _ => None,
+            Some("SIT") => Ok(DogCommand::Sit),
+            Some("HEEL") => Ok(DogCommand::Heel),
+            Some("DOWN") => Ok(DogCommand::Down),
+            _ => Err("Unknown command".into()),
         }
     }
 }
@@ -314,13 +316,15 @@ impl<S> FromInputValue<S> for FurColor
 where
     S: ScalarValue,
 {
-    fn from_input_value<'a>(v: &InputValue<S>) -> Option<FurColor> {
+    type Error = FieldError<S>;
+
+    fn from_input_value<'a>(v: &InputValue<S>) -> Result<FurColor, Self::Error> {
         match v.as_enum_value() {
-            Some("BROWN") => Some(FurColor::Brown),
-            Some("BLACK") => Some(FurColor::Black),
-            Some("TAN") => Some(FurColor::Tan),
-            Some("SPOTTED") => Some(FurColor::Spotted),
-            _ => None,
+            Some("BROWN") => Ok(FurColor::Brown),
+            Some("BLACK") => Ok(FurColor::Black),
+            Some("TAN") => Ok(FurColor::Tan),
+            Some("SPOTTED") => Ok(FurColor::Spotted),
+            _ => Err("Unknown color".into()),
         }
     }
 }
@@ -612,21 +616,37 @@ impl<S> FromInputValue<S> for ComplexInput
 where
     S: ScalarValue,
 {
-    fn from_input_value<'a>(v: &InputValue<S>) -> Option<ComplexInput> {
-        let obj = match v.to_object_value() {
-            Some(o) => o,
-            None => return None,
-        };
-
-        Some(ComplexInput {
-            required_field: match obj.get("requiredField").and_then(|v| v.convert()) {
-                Some(f) => f,
-                None => return None,
-            },
-            int_field: obj.get("intField").and_then(|v| v.convert()),
-            string_field: obj.get("stringField").and_then(|v| v.convert()),
-            boolean_field: obj.get("booleanField").and_then(|v| v.convert()),
-            string_list_field: obj.get("stringListField").and_then(|v| v.convert()),
+    type Error = FieldError<S>;
+
+    fn from_input_value<'a>(v: &InputValue<S>) -> Result<ComplexInput, Self::Error> {
+        let obj = v.to_object_value().ok_or("Expected object")?;
+
+        Ok(ComplexInput {
+            required_field: obj
+                .get("requiredField")
+                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .transpose()?
+                .ok_or("Expected requiredField")?,
+            int_field: obj
+                .get("intField")
+                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .transpose()?
+                .ok_or("Expected requiredField")?,
+            string_field: obj
+                .get("stringField")
+                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .transpose()?
+                .ok_or("Expected requiredField")?,
+            boolean_field: obj
+                .get("booleanField")
+                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .transpose()?
+                .ok_or("Expected requiredField")?,
+            string_list_field: obj
+                .get("stringListField")
+                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .transpose()?
+                .ok_or("Expected requiredField")?,
         })
     }
 }
diff --git a/juniper_codegen/src/common/field/arg.rs b/juniper_codegen/src/common/field/arg.rs
index 5dfaa904a..56e01afca 100644
--- a/juniper_codegen/src/common/field/arg.rs
+++ b/juniper_codegen/src/common/field/arg.rs
@@ -351,14 +351,63 @@ impl OnMethod {
         match self {
             Self::Regular(arg) => {
                 let (name, ty) = (&arg.name, &arg.ty);
-                let err_text = format!(
-                    "Internal error: missing argument `{}` - validation must have failed",
-                    &name,
-                );
+                let err_text = format!("Missing argument `{}`: {{}}", &name);
                 quote! {
                     args.get::<#ty>(#name)
-                        .or_else(::juniper::FromInputValue::<#scalar>::from_implicit_null)
-                        .expect(#err_text)
+                        .and_then(|opt| {
+                            opt.map_or_else(
+                                || {
+                                    <#ty as ::juniper::FromInputValue<#scalar>>::from_implicit_null()
+                                        .map_err(|e| {
+                                            let mut e = ::juniper::IntoFieldError::into_field_error(e);
+                                            e.message = format!(#err_text, e.message);
+                                            e
+                                        })
+                                },
+                                Ok,
+                            )
+                        })?
+                }
+            }
+
+            Self::Context(_) => quote! {
+                ::juniper::FromContext::from(executor.context())
+            },
+
+            Self::Executor => quote! { &executor },
+        }
+    }
+
+    /// Returns generated code for the [`GraphQLValue::resolve_field`] method,
+    /// which provides the value of this [`OnMethod`] argument to be passed into
+    /// a trait method call.
+    ///
+    /// [`GraphQLValue::resolve_field`]: juniper::GraphQLValue::resolve_field
+    #[must_use]
+    pub(crate) fn method_resolve_field_async_tokens(&self, scalar: &scalar::Type) -> TokenStream {
+        match self {
+            Self::Regular(arg) => {
+                let (name, ty) = (&arg.name, &arg.ty);
+                let err_text = format!("Missing argument `{}`: {{}}", &name);
+                quote! {
+                    match args.get::<#ty>(#name)
+                        .and_then(|opt| {
+                            opt.map_or_else(
+                                || {
+                                    <#ty as ::juniper::FromInputValue<#scalar>>::from_implicit_null()
+                                        .map_err(|e| {
+                                            let mut e = ::juniper::IntoFieldError::into_field_error(e);
+                                            e.message = format!(#err_text, e.message);
+                                            e
+                                        })
+                                },
+                                Ok,
+                            )
+                        })
+                    {
+                        Ok(ok) => ok,
+                        Err(err) => return Box::pin(async { Err(err) }),
+                    }
                 }
             }
 
diff --git a/juniper_codegen/src/common/field/mod.rs b/juniper_codegen/src/common/field/mod.rs
index a627e444b..360cb28bb 100644
--- a/juniper_codegen/src/common/field/mod.rs
+++ b/juniper_codegen/src/common/field/mod.rs
@@ -274,13 +274,14 @@ impl Definition {
     /// [`GraphQLValue::resolve_field`]: juniper::GraphQLValue::resolve_field
     /// [1]: https://spec.graphql.org/June2018/#sec-Language.Fields
     #[must_use]
-    pub(crate) fn method_resolve_field_panic_no_field_tokens(scalar: &scalar::Type) -> TokenStream {
+    pub(crate) fn method_resolve_field_err_no_field_tokens(scalar: &scalar::Type) -> TokenStream {
         quote! {
-            panic!(
+            return Err(::juniper::FieldError::<#scalar>::from(format!(
                 "Field `{}` not found on type `{}`",
                 field,
-                <Self as ::juniper::GraphQLType<#scalar>>::name(info).unwrap(),
-            )
+                <Self as ::juniper::GraphQLType<#scalar>>::name(info)
+                    .ok_or_else(|| ::juniper::FieldError::<#scalar>::from("No name for GraphQLType"))?,
+            )))
         }
     }
 
@@ -291,16 +292,19 @@ impl Definition {
     /// [`GraphQLValue::resolve_field`]: juniper::GraphQLValue::resolve_field
     /// [1]: https://spec.graphql.org/June2018/#sec-Language.Fields
     #[must_use]
-    pub(crate) fn method_resolve_field_panic_async_field_tokens(
+    pub(crate) fn method_resolve_field_err_async_field_tokens(
         field_names: &[&str],
         scalar: &scalar::Type,
     ) -> TokenStream {
         quote! {
-            #( #field_names )|* => panic!(
-                "Tried to resolve async field `{}` on type `{}` with a sync resolver",
-                field,
-                <Self as ::juniper::GraphQLType<#scalar>>::name(info).unwrap(),
-            ),
+            #( #field_names )|* => return Err(::juniper::FieldError::<#scalar>::from(
+                format!(
+                    "Tried to resolve async field `{}` on type `{}` with a sync resolver",
+                    field,
+                    <Self as ::juniper::GraphQLType<#scalar>>::name(info)
+                        .ok_or_else(|| ::juniper::FieldError::<#scalar>::from("No name for GraphQLType"))?,
+                )
+            )),
         }
     }
 
@@ -455,7 +459,7 @@ impl Definition {
                 .as_ref()
                 .unwrap()
                 .iter()
-                .map(|arg| arg.method_resolve_field_tokens(scalar));
+                .map(|arg| arg.method_resolve_field_async_tokens(scalar));
 
             let rcv = self.has_receiver.then(|| {
                 quote! { self, }
diff --git a/juniper_codegen/src/derive_scalar_value.rs b/juniper_codegen/src/derive_scalar_value.rs
index 12a5136b6..a3c87c674 100644
--- a/juniper_codegen/src/derive_scalar_value.rs
+++ b/juniper_codegen/src/derive_scalar_value.rs
@@ -197,9 +197,13 @@ fn impl_scalar_struct(
         where
             #scalar: ::juniper::ScalarValue,
         {
-            fn from_input_value(v: &::juniper::InputValue<#scalar>) -> Option<#ident> {
+            type Error = <#inner_ty as ::juniper::FromInputValue<#scalar>>::Error;
+
+            fn from_input_value(
+                v: &::juniper::InputValue<#scalar>
+            ) -> Result<#ident, <#inner_ty as ::juniper::FromInputValue<#scalar>>::Error> {
                 let inner: #inner_ty = ::juniper::FromInputValue::<#scalar>::from_input_value(v)?;
-                Some(#ident(inner))
+                Ok(#ident(inner))
             }
         }
 
diff --git a/juniper_codegen/src/graphql_interface/mod.rs b/juniper_codegen/src/graphql_interface/mod.rs
index 32d01cfeb..60c64db68 100644
--- a/juniper_codegen/src/graphql_interface/mod.rs
+++ b/juniper_codegen/src/graphql_interface/mod.rs
@@ -585,10 +585,10 @@ impl Definition {
                 .filter_map(|f| f.is_async.then(|| f.name.as_str()))
                 .collect::<Vec<_>>();
             (!names.is_empty()).then(|| {
-                field::Definition::method_resolve_field_panic_async_field_tokens(&names, scalar)
+                field::Definition::method_resolve_field_err_async_field_tokens(&names, scalar)
             })
         };
-        let no_field_panic = field::Definition::method_resolve_field_panic_no_field_tokens(scalar);
+        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
 
         let custom_downcast_checks = self
             .implementers
@@ -624,7 +624,7 @@ impl Definition {
                     match field {
                         #( #fields_resolvers )*
                         #async_fields_panic
-                        _ => #no_field_panic,
+                        _ => #no_field_err,
                     }
                 }
 
@@ -668,7 +668,7 @@ impl Definition {
             .fields
             .iter()
             .map(|f| f.method_resolve_field_async_tokens(scalar, Some(&trait_ty)));
-        let no_field_panic = field::Definition::method_resolve_field_panic_no_field_tokens(scalar);
+        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
 
         let custom_downcasts = self
             .implementers
@@ -690,7 +690,7 @@ impl Definition {
                 ) -> ::juniper::BoxFuture<'b, ::juniper::ExecutionResult<#scalar>> {
                     match field {
                         #( #fields_resolvers )*
-                        _ => #no_field_panic,
+                        _ => Box::pin(async move { #no_field_err }),
                     }
                 }
 
diff --git a/juniper_codegen/src/graphql_object/mod.rs b/juniper_codegen/src/graphql_object/mod.rs
index 267fde795..0157bcca5 100644
--- a/juniper_codegen/src/graphql_object/mod.rs
+++ b/juniper_codegen/src/graphql_object/mod.rs
@@ -500,10 +500,10 @@ impl Definition<Query> {
                 .filter_map(|f| f.is_async.then(|| f.name.as_str()))
                 .collect::<Vec<_>>();
             (!names.is_empty()).then(|| {
-                field::Definition::method_resolve_field_panic_async_field_tokens(&names, scalar)
+                field::Definition::method_resolve_field_err_async_field_tokens(&names, scalar)
             })
         };
-        let no_field_panic = field::Definition::method_resolve_field_panic_no_field_tokens(scalar);
+        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
 
         quote! {
             #[allow(deprecated)]
@@ -527,7 +527,7 @@ impl Definition<Query> {
                     match field {
                         #( #fields_resolvers )*
                         #async_fields_panic
-                        _ => #no_field_panic,
+                        _ => #no_field_err,
                     }
                 }
 
@@ -558,7 +558,7 @@ impl Definition<Query> {
             .fields
             .iter()
             .map(|f| f.method_resolve_field_async_tokens(scalar, None));
-        let no_field_panic = field::Definition::method_resolve_field_panic_no_field_tokens(scalar);
+        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
 
         quote! {
             #[allow(deprecated, non_snake_case)]
@@ -574,7 +574,7 @@ impl Definition<Query> {
                 ) -> ::juniper::BoxFuture<'b, ::juniper::ExecutionResult<#scalar>> {
                     match field {
                         #( #fields_resolvers )*
-                        _ => #no_field_panic,
+                        _ => Box::pin(async move { #no_field_err }),
                     }
                 }
             }
diff --git a/juniper_codegen/src/graphql_subscription/mod.rs b/juniper_codegen/src/graphql_subscription/mod.rs
index 8f6b0e06f..01b03702d 100644
--- a/juniper_codegen/src/graphql_subscription/mod.rs
+++ b/juniper_codegen/src/graphql_subscription/mod.rs
@@ -100,7 +100,7 @@ impl Definition<Subscription> {
             .fields
             .iter()
             .map(|f| f.method_resolve_field_into_stream_tokens(scalar));
-        let no_field_panic = field::Definition::method_resolve_field_panic_no_field_tokens(scalar);
+        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
 
         quote! {
             #[allow(deprecated)]
@@ -130,7 +130,7 @@ impl Definition<Subscription> {
                 {
                     match field {
                         #( #fields_resolvers )*
-                        _ => #no_field_panic,
+                        _ => Box::pin(async move { #no_field_err }),
                     }
                 }
             }
diff --git a/juniper_codegen/src/impl_scalar.rs b/juniper_codegen/src/impl_scalar.rs
index 8109f147f..f05ea91ba 100644
--- a/juniper_codegen/src/impl_scalar.rs
+++ b/juniper_codegen/src/impl_scalar.rs
@@ -309,6 +309,8 @@ pub fn build_scalar(
         impl#generic_type_decl ::juniper::FromInputValue<#generic_type> for #impl_for_type
         #generic_type_bound
         {
+            type Error = <#from_input_value_result as ::juniper::ExtractErrorFromResult>::Error;
+
             fn from_input_value(#from_input_value_arg: &::juniper::InputValue<#generic_type>) -> #from_input_value_result {
                 #from_input_value_body
             }
diff --git a/juniper_codegen/src/lib.rs b/juniper_codegen/src/lib.rs
index e0b0729c9..f4f3cc475 100644
--- a/juniper_codegen/src/lib.rs
+++ b/juniper_codegen/src/lib.rs
@@ -230,8 +230,10 @@ pub fn derive_scalar_value(input: TokenStream) -> TokenStream {
 ///         juniper::Value::scalar(self.0.to_owned())
 ///     }
 ///
-///     fn from_input_value(value: &juniper::InputValue) -> Option<UserID> {
-///         value.as_string_value().map(|s| UserID(s.to_owned()))
+///     fn from_input_value(value: &juniper::InputValue) -> Result<UserID, juniper::FieldError> {
+///         Ok(value.as_string_value()
+///             .map(|s| UserID(s.to_owned()))
+///             .ok_or_else(|| format!("Expected String, found: {}", v))?)
 ///     }
 ///
 ///     fn from_str<'a>(value: juniper::ScalarToken<'a>) -> juniper::ParseScalarResult<'a, S> {
diff --git a/juniper_codegen/src/util/mod.rs b/juniper_codegen/src/util/mod.rs
index ae84fa65d..bb9bcbf44 100644
--- a/juniper_codegen/src/util/mod.rs
+++ b/juniper_codegen/src/util/mod.rs
@@ -752,7 +752,7 @@ impl GraphQLTypeDefiniton {
             let resolver_code = &variant.resolver_code;
 
             quote!(
-                Some(#variant_name) => Some(#resolver_code),
+                Some(#variant_name) => Ok(#resolver_code),
             )
         });
 
@@ -860,13 +860,18 @@ impl GraphQLTypeDefiniton {
             impl#impl_generics ::juniper::FromInputValue<#scalar> for #ty
                 #where_clause
             {
-                fn from_input_value(v: &::juniper::InputValue<#scalar>) -> Option<#ty>
-                {
+                type Error = ::juniper::FieldError<#scalar>;
+
+                fn from_input_value(
+                    v: &::juniper::InputValue<#scalar>
+                ) -> Result<#ty, ::juniper::FieldError<#scalar>> {
                     match v.as_enum_value().or_else(|| {
                         v.as_string_value()
                     }) {
                         #( #from_inputs )*
-                        _ => None,
+                        _ => Err(::juniper::FieldError::<#scalar>::from(
+                            format!("Unknown Enum value: {}", v))
+                        ),
                     }
                 }
             }
@@ -980,8 +985,14 @@ impl GraphQLTypeDefiniton {
                     #field_ident: {
                         match obj.get(#field_name) {
                             #from_input_default
-                            Some(ref v) => ::juniper::FromInputValue::from_input_value(v)?,
-                            None => ::juniper::FromInputValue::<#scalar>::from_implicit_null()?,
+                            Some(ref v) => {
+                                ::juniper::FromInputValue::from_input_value(v)
+                                    .map_err(::juniper::IntoFieldError::into_field_error)?
+                            },
+                            None => {
+                                ::juniper::FromInputValue::<#scalar>::from_implicit_null()
+                                    .map_err(::juniper::IntoFieldError::into_field_error)?
+                            },
                         }
                     },
                 )
@@ -1096,10 +1107,16 @@ impl GraphQLTypeDefiniton {
             impl#impl_generics ::juniper::FromInputValue<#scalar> for #ty #type_generics_tokens
                 #where_clause
             {
-                fn from_input_value(value: &::juniper::InputValue<#scalar>) -> Option<Self>
-                {
-                    let obj = value.to_object_value()?;
-                    Some(#ty {
+                type Error = ::juniper::FieldError<#scalar>;
+
+                fn from_input_value(
+                    value: &::juniper::InputValue<#scalar>
+                ) -> Result<Self, ::juniper::FieldError<#scalar>> {
+                    let obj = value.to_object_value()
+                        .ok_or_else(|| ::juniper::FieldError::<#scalar>::from(
+                            format!("Expected Object, found: {}", value))
+                        )?;
+                    Ok(#ty {
                         #( #from_inputs )*
                     })
                 }

From 111e464d5844847dd75502d45ebd1449d6992c75 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Wed, 1 Dec 2021 14:27:56 +0300
Subject: [PATCH 06/25] Remove more unwraps and panics

---
 juniper_codegen/src/graphql_interface/mod.rs  | 21 +++++++----
 juniper_codegen/src/graphql_object/mod.rs     |  4 +--
 .../src/graphql_subscription/mod.rs           |  4 ++-
 juniper_codegen/src/graphql_union/mod.rs      | 35 +++++++++++++------
 4 files changed, 44 insertions(+), 20 deletions(-)

diff --git a/juniper_codegen/src/graphql_interface/mod.rs b/juniper_codegen/src/graphql_interface/mod.rs
index 60c64db68..a509d3cf1 100644
--- a/juniper_codegen/src/graphql_interface/mod.rs
+++ b/juniper_codegen/src/graphql_interface/mod.rs
@@ -578,7 +578,7 @@ impl Definition {
             .fields
             .iter()
             .filter_map(|f| f.method_resolve_field_tokens(scalar, Some(&trait_ty)));
-        let async_fields_panic = {
+        let async_fields_err = {
             let names = self
                 .fields
                 .iter()
@@ -623,7 +623,7 @@ impl Definition {
                 ) -> ::juniper::ExecutionResult<#scalar> {
                     match field {
                         #( #fields_resolvers )*
-                        #async_fields_panic
+                        #async_fields_err
                         _ => #no_field_err,
                     }
                 }
@@ -847,7 +847,9 @@ impl Implementer {
         let resolving_code = gen::sync_resolving_code();
 
         Some(quote! {
-            if type_name == <#ty as ::juniper::GraphQLType<#scalar>>::name(info).unwrap() {
+            if type_name == <#ty as ::juniper::GraphQLType<#scalar>>::name(info)
+                .ok_or_else(|| ::juniper::FieldError::from("This GraphQLType has no name"))?
+            {
                 let res = #downcast;
                 return #resolving_code;
             }
@@ -875,9 +877,16 @@ impl Implementer {
         let resolving_code = gen::async_resolving_code(None);
 
         Some(quote! {
-            if type_name == <#ty as ::juniper::GraphQLType<#scalar>>::name(info).unwrap() {
-                let fut = ::juniper::futures::future::ready(#downcast);
-                return #resolving_code;
+            match <#ty as ::juniper::GraphQLType<#scalar>>::name(info) {
+                Some(name) => {
+                    if type_name == name {
+                        let fut = ::juniper::futures::future::ready(#downcast);
+                        return #resolving_code;
+                    }
+                }
+                None => return Box::pin(::juniper::futures::future::ready(
+                    Err(::juniper::FieldError::from("This GraphQLType has no name"))
+                )),
             }
         })
     }
diff --git a/juniper_codegen/src/graphql_object/mod.rs b/juniper_codegen/src/graphql_object/mod.rs
index 0157bcca5..dd9a1b3a6 100644
--- a/juniper_codegen/src/graphql_object/mod.rs
+++ b/juniper_codegen/src/graphql_object/mod.rs
@@ -493,7 +493,7 @@ impl Definition<Query> {
             .fields
             .iter()
             .filter_map(|f| f.method_resolve_field_tokens(scalar, None));
-        let async_fields_panic = {
+        let async_fields_err = {
             let names = self
                 .fields
                 .iter()
@@ -526,7 +526,7 @@ impl Definition<Query> {
                 ) -> ::juniper::ExecutionResult<#scalar> {
                     match field {
                         #( #fields_resolvers )*
-                        #async_fields_panic
+                        #async_fields_err
                         _ => #no_field_err,
                     }
                 }
diff --git a/juniper_codegen/src/graphql_subscription/mod.rs b/juniper_codegen/src/graphql_subscription/mod.rs
index 01b03702d..288547485 100644
--- a/juniper_codegen/src/graphql_subscription/mod.rs
+++ b/juniper_codegen/src/graphql_subscription/mod.rs
@@ -60,7 +60,9 @@ impl Definition<Subscription> {
                     _: &::juniper::Arguments<#scalar>,
                     _: &::juniper::Executor<Self::Context, #scalar>,
                 ) -> ::juniper::ExecutionResult<#scalar> {
-                    panic!("Called `resolve_field` on subscription object");
+                    Err(::juniper::FieldError::from(
+                        "Called `resolve_field` on subscription object"
+                    ))
                 }
 
                 fn concrete_type_name(
diff --git a/juniper_codegen/src/graphql_union/mod.rs b/juniper_codegen/src/graphql_union/mod.rs
index c882c24ba..040ce97f4 100644
--- a/juniper_codegen/src/graphql_union/mod.rs
+++ b/juniper_codegen/src/graphql_union/mod.rs
@@ -558,11 +558,12 @@ impl Definition {
                 ) -> ::juniper::ExecutionResult<#scalar> {
                     let context = executor.context();
                     #( #variant_resolvers )*
-                    panic!(
+
+                    return Err(::juniper::FieldError::from(format!(
                         "Concrete type `{}` is not handled by instance \
                          resolvers on GraphQL union `{}`",
                         type_name, #name,
-                    );
+                    )));
                 }
             }
         }
@@ -600,11 +601,14 @@ impl Definition {
                 ) -> ::juniper::BoxFuture<'b, ::juniper::ExecutionResult<#scalar>> {
                     let context = executor.context();
                     #( #variant_async_resolvers )*
-                    panic!(
-                        "Concrete type `{}` is not handled by instance \
-                         resolvers on GraphQL union `{}`",
-                        type_name, #name,
-                    );
+
+                    return Box::pin(::juniper::futures::future::ready(
+                        Err(::juniper::FieldError::from(format!(
+                            "Concrete type `{}` is not handled by instance \
+                            resolvers on GraphQL union `{}`",
+                            type_name, #name,
+                        )))
+                    ));
                 }
             }
         }
@@ -674,7 +678,9 @@ impl VariantDefinition {
         let resolving_code = gen::sync_resolving_code();
 
         quote! {
-            if type_name == <#ty as ::juniper::GraphQLType<#scalar>>::name(info).unwrap() {
+            if type_name == <#ty as ::juniper::GraphQLType<#scalar>>::name(info)
+                .ok_or_else(|| ::juniper::FieldError::from("This GraphQLType has no name"))?
+            {
                 let res = { #expr };
                 return #resolving_code;
             }
@@ -694,9 +700,16 @@ impl VariantDefinition {
         let resolving_code = gen::async_resolving_code(None);
 
         quote! {
-            if type_name == <#ty as ::juniper::GraphQLType<#scalar>>::name(info).unwrap() {
-                let fut = ::juniper::futures::future::ready({ #expr });
-                return #resolving_code;
+            match <#ty as ::juniper::GraphQLType<#scalar>>::name(info) {
+                Some(name) => {
+                    if type_name == name {
+                        let fut = ::juniper::futures::future::ready({ #expr });
+                        return #resolving_code;
+                    }
+                }
+                None => return Box::pin(::juniper::futures::future::ready(
+                    Err(::juniper::FieldError::from("This GraphQLType has no name"))
+                )),
             }
         }
     }

From 555db09585d6f9f2f20850c9b1df07b8732a1b99 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Wed, 1 Dec 2021 15:21:37 +0300
Subject: [PATCH 07/25] Fix ui codegen tests

---
 err.txt                                       | 836 ++++++++++++++++++
 .../fail/enum/derive_no_fields.stderr         |   9 +-
 .../derive_incompatible_object.stderr         |  40 +-
 .../fail/input-object/derive_no_fields.stderr |   9 +-
 .../input-object/derive_no_underscore.stderr  |   7 +-
 .../input-object/derive_unique_name.stderr    |  12 +-
 .../argument_double_underscored.stderr        |   5 +-
 .../interface/argument_non_input_type.stderr  |  20 +-
 ...conflicts_with_external_downcast_fn.stderr |   9 +-
 .../downcast_method_wrong_input_args.stderr   |   7 +-
 .../downcast_method_wrong_return_type.stderr  |  13 +-
 .../interface/field_double_underscored.stderr |  11 +-
 .../field_non_output_return_type.stderr       |  18 +-
 .../fail/interface/fields_duplicate.stderr    |  21 +-
 .../implementer_non_object_type.stderr        |  26 +-
 .../interface/name_double_underscored.stderr  |   5 +-
 .../fail/interface/no_fields.stderr           |   7 +-
 .../object/argument_double_underscored.stderr |   7 +-
 .../object/argument_non_input_type.stderr     |  20 +-
 .../attr_field_non_output_return_type.stderr  |  18 +-
 .../fail/object/attr_fields_duplicate.stderr  |   7 +-
 .../attr_name_double_underscored.stderr       |   7 +-
 .../fail/object/attr_no_fields.stderr         |   7 +-
 .../derive_field_double_underscored.stderr    |   7 +-
 ...derive_field_non_output_return_type.stderr |  18 +-
 .../object/derive_fields_duplicate.stderr     |  15 +-
 .../derive_name_double_underscored.stderr     |   7 +-
 .../fail/object/derive_no_fields.stderr       |   9 +-
 .../fail/object/derive_wrong_item.stderr      |   4 +-
 .../argument_double_underscored.stderr        |   7 +-
 .../argument_non_input_type.stderr            |  20 +-
 .../field_non_output_return_type.stderr       |  18 +-
 .../fail/subscription/field_not_async.stderr  |  11 +-
 .../fail/subscription/fields_duplicate.stderr |   7 +-
 .../name_double_underscored.stderr            |   7 +-
 .../fail/subscription/no_fields.stderr        |   7 +-
 .../fail/union/derive_wrong_item.stderr       |   4 +-
 ...s_with_variant_external_resolver_fn.stderr |   7 +-
 .../union/enum_name_double_underscored.stderr |   7 +-
 .../fail/union/enum_no_fields.stderr          |   9 +-
 .../fail/union/enum_non_object_variant.stderr |  18 +-
 .../fail/union/enum_same_type_pretty.stderr   |  14 +-
 .../union/enum_wrong_variant_field.stderr     |  14 +-
 .../struct_name_double_underscored.stderr     |   7 +-
 .../fail/union/struct_no_fields.stderr        |   9 +-
 .../union/struct_non_object_variant.stderr    |  18 +-
 .../union/trait_fail_infer_context.stderr     |  20 +-
 ...conflicts_with_external_resolver_fn.stderr |  11 +-
 .../trait_name_double_underscored.stderr      |   7 +-
 .../fail/union/trait_no_fields.stderr         |   9 +-
 .../union/trait_non_object_variant.stderr     |  18 +-
 .../fail/union/trait_same_type_pretty.stderr  |  14 +-
 .../union/trait_with_attr_on_method.stderr    |   9 +-
 .../trait_wrong_method_input_args.stderr      |   9 +-
 .../trait_wrong_method_return_type.stderr     |   9 +-
 juniper_codegen/src/lib.rs                    |   2 +-
 56 files changed, 1196 insertions(+), 277 deletions(-)
 create mode 100644 err.txt

diff --git a/err.txt b/err.txt
new file mode 100644
index 000000000..e397bf1d6
--- /dev/null
+++ b/err.txt
@@ -0,0 +1,836 @@
+/Users/work/.cargo/bin/cargo +stable test --color=always -p juniper_codegen_tests --all-features --no-fail-fast -- --format=json -Z unstable-options --show-output
+Testing started at 15:02 ...
+    Finished test [unoptimized + debuginfo] target(s) in 0.20s
+     Running unittests (/Users/work/Work/juniper/target/debug/deps/juniper_codegen_tests-0ab20148dc3374c3)
+    Checking juniper_codegen_tests-tests v0.0.0 (/Users/work/Work/juniper/target/tests/juniper_codegen_tests)
+    Finished dev [unoptimized + debuginfo] target(s) in 0.28s
+
+
+test fail/interface/field_double_underscored.rs ... ok
+test fail/interface/implementers_duplicate_pretty.rs ... ok
+test fail/interface/downcast_method_wrong_input_args.rs ... ok
+test fail/interface/argument_wrong_default_array.rs ... ok
+test fail/interface/wrong_item.rs ... ok
+test fail/interface/name_double_underscored.rs ... ok
+test fail/interface/argument_double_underscored.rs ... ok
+test fail/interface/argument_non_input_type.rs ... ok
+test fail/interface/downcast_method_conflicts_with_external_downcast_fn.rs ... ok
+test fail/interface/no_fields.rs ... ok
+test fail/interface/field_non_output_return_type.rs ... ok
+test fail/interface/implementers_duplicate_ugly.rs ... ok
+test fail/interface/downcast_method_wrong_return_type.rs ... ok
+test fail/interface/fields_duplicate.rs ... ok
+test fail/interface/implementer_non_object_type.rs ... ok
+test fail/input-object/derive_no_fields.rs ... ok
+test fail/input-object/derive_unique_name.rs ... ok
+test fail/input-object/derive_no_underscore.rs ... ok
+test fail/input-object/derive_incompatible_object.rs ... ok
+test fail/enum/derive_no_fields.rs ... ok
+test fail/subscription/field_double_underscored.rs ... ok
+test fail/subscription/field_not_async.rs ... ok
+test fail/subscription/argument_wrong_default_array.rs ... ok
+test fail/subscription/wrong_item.rs ... ok
+test fail/subscription/name_double_underscored.rs ... ok
+test fail/subscription/argument_double_underscored.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+  --> fail/subscription/argument_double_underscored.rs:11:24
+   |
+11 |     async fn id(&self, __num: i32) -> Stream<'static, &'static str> {
+   |
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+  --> fail/subscription/argument_double_underscored.rs:11:24
+   |
+11 |     async fn id(&self, __num: i32) -> Stream<'static, &'static str> {
+   |                        ^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/subscription/argument_non_input_type.rs ... ok
+test fail/subscription/no_fields.rs ... ok
+test fail/subscription/field_non_output_return_type.rs ... ok
+test fail/subscription/fields_duplicate.rs ... ok
+test fail/object/derive_field_double_underscored.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+ --> $DIR/derive_field_double_underscored.rs:5:5
+  |
+5 |     __test: String,
+  |     ^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/object/derive_field_double_underscored.rs:5:5
+  |
+5 |     __test: String,
+  |     ^^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/object/derive_no_fields.rs ... ok
+test fail/object/derive_wrong_item.rs ... ok
+test fail/object/attr_fields_duplicate.rs ... ok
+test fail/object/argument_wrong_default_array.rs ... ok
+test fail/object/argument_double_underscored.rs ... ok
+test fail/object/argument_non_input_type.rs ... ok
+test fail/object/attr_no_fields.rs ... { "type": "test", "event": "timeout", "name": "test_failing_compiliation" }
+ok
+test fail/object/attr_name_double_underscored.rs ... ok
+test fail/object/derive_name_double_underscored.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/object/derive_field_double_underscored.rs:5:5
+  |
+5 |     __test: String,
+  |     ^^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/object/derive_name_double_underscored.rs:4:8
+  |
+4 | struct __Obj {
+  |        ^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/object/derive_fields_duplicate.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL object must have a different name for each field
+ --> $DIR/derive_fields_duplicate.rs:4:1
+  |
+4 | / struct ObjA {
+5 | |     id: String,
+6 | |     #[graphql(name = "id")]
+7 | |     id2: String,
+8 | | }
+  | |_^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Objects
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL object must have a different name for each field
+
+  = note: https://spec.graphql.org/June2018/#sec-Objects
+
+ --> fail/object/derive_fields_duplicate.rs:4:1
+  |
+4 | struct ObjA {
+  | ^^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/object/attr_wrong_item.rs ... ok
+test fail/object/attr_field_non_output_return_type.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
+  --> $DIR/attr_field_non_output_return_type.rs:10:1
+   |
+10 | #[graphql_object]
+   | ^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
+   |
+   = note: required by `juniper::marker::IsOutputType::mark`
+   = note: this error originates in the attribute macro `graphql_object` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
+   --> fail/object/attr_field_non_output_return_type.rs:10:1
+    |
+10  | #[graphql_object]
+    | ^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
+    |
+note: required by `juniper::marker::IsOutputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_object` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/object/attr_field_double_underscored.rs ... ok
+test fail/object/derive_field_non_output_return_type.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
+ --> $DIR/derive_field_non_output_return_type.rs:8:10
+  |
+8 | #[derive(GraphQLObject)]
+  |          ^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
+  |
+  = note: required by `juniper::marker::IsOutputType::mark`
+  = note: this error originates in the derive macro `GraphQLObject` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
+   --> fail/object/derive_field_non_output_return_type.rs:8:10
+    |
+8   | #[derive(GraphQLObject)]
+    |          ^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
+    |
+note: required by `juniper::marker::IsOutputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the derive macro `GraphQLObject` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/enum_wrong_variant_field.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
+ --> $DIR/enum_wrong_variant_field.rs:5:5
+  |
+5 |     A { human: Human },
+  |     ^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
+  --> $DIR/enum_wrong_variant_field.rs:10:6
+   |
+10 |     A(Human, u8),
+   |      ^^^^^^^^^^^
+   |
+   = note: https://spec.graphql.org/June2018/#sec-Unions
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/enum_wrong_variant_field.rs:5:5
+  |
+5 |     A { human: Human },
+  |     ^
+
+error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+  --> fail/union/enum_wrong_variant_field.rs:10:6
+   |
+10 |     A(Human, u8),
+   |      ^^^^^^^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/struct_non_object_variant.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
+ --> $DIR/struct_non_object_variant.rs:9:10
+  |
+9 | #[derive(GraphQLUnion)]
+  |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
+  |
+  = note: required by `juniper::GraphQLObject::mark`
+  = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
+  --> fail/union/struct_non_object_variant.rs:9:10
+   |
+9  | #[derive(GraphQLUnion)]
+   |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
+   |
+note: required by `juniper::GraphQLObject::mark`
+  --> $WORKSPACE/juniper/src/types/marker.rs
+   |
+   |     fn mark() {}
+   |     ^^^^^^^^^
+   = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/struct_same_type_pretty.rs ... ok
+test fail/union/trait_fail_infer_context.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `CustomContext: FromContext<SubContext>` is not satisfied
+ --> $DIR/trait_fail_infer_context.rs:3:1
+  |
+3 | #[graphql_union]
+  | ^^^^^^^^^^^^^^^^ expected an implementor of trait `FromContext<SubContext>`
+  |
+  = note: required by `juniper::FromContext::from`
+  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0308]: mismatched types
+ --> $DIR/trait_fail_infer_context.rs:3:1
+  |
+3 | #[graphql_union]
+  | ^^^^^^^^^^^^^^^^ expected struct `CustomContext`, found struct `SubContext`
+  |
+  = note: expected reference `&CustomContext`
+             found reference `&SubContext`
+  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `CustomContext: FromContext<SubContext>` is not satisfied
+   --> fail/union/trait_fail_infer_context.rs:3:1
+    |
+3   | #[graphql_union]
+    | ^^^^^^^^^^^^^^^^ expected an implementor of trait `FromContext<SubContext>`
+    |
+note: required by `juniper::FromContext::from`
+   --> $WORKSPACE/juniper/src/executor/mod.rs
+    |
+    |     fn from(value: &T) -> &Self;
+    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0308]: mismatched types
+ --> fail/union/trait_fail_infer_context.rs:3:1
+  |
+3 | #[graphql_union]
+  | ^^^^^^^^^^^^^^^^ expected struct `CustomContext`, found struct `SubContext`
+  |
+  = note: expected reference `&CustomContext`
+             found reference `&SubContext`
+  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/derive_wrong_item.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union can only be derived for enums and structs
+ --> $DIR/derive_wrong_item.rs:4:1
+  |
+4 | union Character { id: i32 }
+  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union can only be derived for enums and structs
+ --> fail/union/derive_wrong_item.rs:4:1
+  |
+4 | union Character { id: i32 }
+  | ^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/enum_no_fields.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects at least one union variant
+ --> $DIR/enum_no_fields.rs:4:1
+  |
+4 | enum Character {}
+  | ^^^^^^^^^^^^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects at least one union variant
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/enum_no_fields.rs:4:1
+  |
+4 | enum Character {}
+  | ^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/enum_same_type_pretty.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union must have a different type for each union variant
+ --> $DIR/enum_same_type_pretty.rs:4:1
+  |
+4 | / enum Character {
+5 | |     A(u8),
+6 | |     B(u8),
+7 | | }
+  | |_^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union must have a different type for each union variant
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/enum_same_type_pretty.rs:4:1
+  |
+4 | enum Character {
+  | ^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/trait_no_fields.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects at least one union variant
+ --> $DIR/trait_no_fields.rs:4:1
+  |
+4 | trait Character {}
+  | ^^^^^^^^^^^^^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects at least one union variant
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/trait_no_fields.rs:4:1
+  |
+4 | trait Character {}
+  | ^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/enum_same_type_ugly.rs ... ok
+test fail/union/trait_same_type_ugly.rs ... ok
+test fail/union/enum_non_object_variant.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
+ --> $DIR/enum_non_object_variant.rs:9:10
+  |
+9 | #[derive(GraphQLUnion)]
+  |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
+  |
+  = note: required by `juniper::GraphQLObject::mark`
+  = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
+  --> fail/union/enum_non_object_variant.rs:9:10
+   |
+9  | #[derive(GraphQLUnion)]
+   |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
+   |
+note: required by `juniper::GraphQLObject::mark`
+  --> $WORKSPACE/juniper/src/types/marker.rs
+   |
+   |     fn mark() {}
+   |     ^^^^^^^^^
+   = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/trait_with_attr_on_method.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union cannot use #[graphql(with = ...)] attribute on a trait method
+ --> $DIR/trait_with_attr_on_method.rs:5:15
+  |
+5 |     #[graphql(with = something)]
+  |               ^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+  = note: instead use #[graphql(ignore)] on the method with #[graphql_union(on ... = ...)] on the trait itself
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union cannot use #[graphql(with = ...)] attribute on a trait method
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+  = note: instead use #[graphql(ignore)] on the method with #[graphql_union(on ... = ...)] on the trait itself
+
+ --> fail/union/trait_with_attr_on_method.rs:5:15
+  |
+5 |     #[graphql(with = something)]
+  |               ^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/trait_wrong_method_input_args.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects trait method to accept `&self` only and, optionally, `&Context`
+ --> $DIR/trait_wrong_method_input_args.rs:5:10
+  |
+5 |     fn a(&self, ctx: &(), rand: u8) -> Option<&Human>;
+  |          ^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects trait method to accept `&self` only and, optionally, `&Context`
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/trait_wrong_method_input_args.rs:5:10
+  |
+5 |     fn a(&self, ctx: &(), rand: u8) -> Option<&Human>;
+  |          ^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/trait_name_double_underscored.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+ --> $DIR/trait_name_double_underscored.rs:4:7
+  |
+4 | trait __Character {
+  |       ^^^^^^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/union/trait_name_double_underscored.rs:4:7
+  |
+4 | trait __Character {
+  |       ^^^^^^^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union variant `Human` already has external resolver function `resolve_fn1` declared on the enum
+ --> $DIR/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.rs:6:15
+  |
+6 |     #[graphql(with = resolve_fn2)]
+  |               ^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union variant `Human` already has external resolver function `resolve_fn1` declared on the enum
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.rs:6:15
+  |
+6 |     #[graphql(with = resolve_fn2)]
+  |               ^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/trait_same_type_pretty.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union must have a different type for each union variant
+ --> $DIR/trait_same_type_pretty.rs:4:1
+  |
+4 | / trait Character {
+5 | |     fn a(&self) -> Option<&u8>;
+6 | |     fn b(&self) -> Option<&u8>;
+7 | | }
+  | |_^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union must have a different type for each union variant
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/trait_same_type_pretty.rs:4:1
+  |
+4 | trait Character {
+  | ^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/attr_wrong_item.rs ... ok
+test fail/union/struct_no_fields.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects at least one union variant
+ --> $DIR/struct_no_fields.rs:4:1
+  |
+4 | struct Character;
+  | ^^^^^^^^^^^^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects at least one union variant
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/struct_no_fields.rs:4:1
+  |
+4 | struct Character;
+  | ^^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/struct_name_double_underscored.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+ --> $DIR/struct_name_double_underscored.rs:5:8
+  |
+5 | struct __Character;
+  |        ^^^^^^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/union/struct_name_double_underscored.rs:5:8
+  |
+5 | struct __Character;
+  |        ^^^^^^^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/trait_method_conflicts_with_external_resolver_fn.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union trait method `a` conflicts with the external resolver function `some_fn` declared on the trait to resolve the variant type `Human`
+ --> $DIR/trait_method_conflicts_with_external_resolver_fn.rs:5:5
+  |
+5 |     fn a(&self) -> Option<&Human>;
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+  = note: use `#[graphql(ignore)]` attribute to ignore this trait method for union variants resolution
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union trait method `a` conflicts with the external resolver function `some_fn` declared on the trait to resolve the variant type `Human`
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+  = note: use `#[graphql(ignore)]` attribute to ignore this trait method for union variants resolution
+
+ --> fail/union/trait_method_conflicts_with_external_resolver_fn.rs:5:5
+  |
+5 |     fn a(&self) -> Option<&Human>;
+  |     ^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/enum_name_double_underscored.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+ --> $DIR/enum_name_double_underscored.rs:4:6
+  |
+4 | enum __Character {
+  |      ^^^^^^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/union/enum_name_double_underscored.rs:4:6
+  |
+4 | enum __Character {
+  |      ^^^^^^^^^^^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/trait_non_object_variant.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
+ --> $DIR/trait_non_object_variant.rs:9:1
+  |
+9 | #[graphql_union]
+  | ^^^^^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
+  |
+  = note: required by `juniper::GraphQLObject::mark`
+  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
+  --> fail/union/trait_non_object_variant.rs:9:1
+   |
+9  | #[graphql_union]
+   | ^^^^^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
+   |
+note: required by `juniper::GraphQLObject::mark`
+  --> $WORKSPACE/juniper/src/types/marker.rs
+   |
+   |     fn mark() {}
+   |     ^^^^^^^^^
+   = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+test fail/union/struct_same_type_ugly.rs ... ok
+test fail/union/trait_wrong_method_return_type.rs ... mismatch
+
+EXPECTED:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects trait method return type to be `Option<&VariantType>` only
+ --> $DIR/trait_wrong_method_return_type.rs:5:20
+  |
+5 |     fn a(&self) -> &Human;
+  |                    ^^^^^^
+  |
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+
+ACTUAL OUTPUT:
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+error: GraphQL union expects trait method return type to be `Option<&VariantType>` only
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/trait_wrong_method_return_type.rs:5:20
+  |
+5 |     fn a(&self) -> &Human;
+  |                    ^
+┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
+note: If the actual output is the correct output you can bless it by rerunning
+      your test with the environment variable TRYBUILD=overwrite
+
+
+
+
+25 of 69 tests failed
+thread 'test_failing_compiliation' panicked at '25 of 69 tests failed', /Users/work/.cargo/registry/src/git.colasdn.top-1ecc6299db9ec823/trybuild-1.0.52/src/run.rs:74:13
+stack backtrace:
+   0: rust_begin_unwind
+             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/std/src/panicking.rs:517:5
+   1: std::panicking::begin_panic_fmt
+             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/std/src/panicking.rs:460:5
+   2: trybuild::run::<impl trybuild::Runner>::run
+             at /Users/work/.cargo/registry/src/git.colasdn.top-1ecc6299db9ec823/trybuild-1.0.52/src/run.rs:74:13
+   3: <trybuild::TestCases as core::ops::drop::Drop>::drop
+             at /Users/work/.cargo/registry/src/git.colasdn.top-1ecc6299db9ec823/trybuild-1.0.52/src/lib.rs:306:13
+   4: core::ptr::drop_in_place<trybuild::TestCases>
+             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/core/src/ptr/mod.rs:188:1
+   5: juniper_codegen_tests::test_failing_compiliation
+             at ./src/lib.rs:38:1
+   6: juniper_codegen_tests::test_failing_compiliation::{{closure}}
+             at ./src/lib.rs:28:1
+   7: core::ops::function::FnOnce::call_once
+             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/core/src/ops/function.rs:227:5
+   8: core::ops::function::FnOnce::call_once
+             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/core/src/ops/function.rs:227:5
+note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
+
+   Doc-tests juniper_codegen_tests
+error: test failed, to rerun pass '-p juniper_codegen_tests --lib'
+
+Process finished with exit code 101
diff --git a/integration_tests/codegen_fail/fail/enum/derive_no_fields.stderr b/integration_tests/codegen_fail/fail/enum/derive_no_fields.stderr
index ccfc49515..8c7fc3604 100644
--- a/integration_tests/codegen_fail/fail/enum/derive_no_fields.stderr
+++ b/integration_tests/codegen_fail/fail/enum/derive_no_fields.stderr
@@ -1,7 +1,8 @@
 error: GraphQL enum expects at least one field
- --> $DIR/derive_no_fields.rs:2:1
+
+  = note: https://spec.graphql.org/June2018/#sec-Enums
+
+ --> fail/enum/derive_no_fields.rs:2:1
   |
 2 | pub enum Test {}
-  | ^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Enums
+  | ^^^
diff --git a/integration_tests/codegen_fail/fail/input-object/derive_incompatible_object.stderr b/integration_tests/codegen_fail/fail/input-object/derive_incompatible_object.stderr
index 988fbab5c..6c4e0ed60 100644
--- a/integration_tests/codegen_fail/fail/input-object/derive_incompatible_object.stderr
+++ b/integration_tests/codegen_fail/fail/input-object/derive_incompatible_object.stderr
@@ -1,14 +1,18 @@
 error[E0277]: the trait bound `ObjectA: IsInputType<__S>` is not satisfied
- --> $DIR/derive_incompatible_object.rs:6:10
-  |
-6 | #[derive(juniper::GraphQLInputObject)]
-  |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsInputType<__S>` is not implemented for `ObjectA`
-  |
-  = note: required by `juniper::marker::IsInputType::mark`
-  = note: this error originates in the derive macro `juniper::GraphQLInputObject` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/input-object/derive_incompatible_object.rs:6:10
+    |
+6   | #[derive(juniper::GraphQLInputObject)]
+    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsInputType<__S>` is not implemented for `ObjectA`
+    |
+note: required by `juniper::marker::IsInputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the derive macro `juniper::GraphQLInputObject` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `ObjectA: FromInputValue<__S>` is not satisfied
- --> $DIR/derive_incompatible_object.rs:6:10
+ --> fail/input-object/derive_incompatible_object.rs:6:10
   |
 6 | #[derive(juniper::GraphQLInputObject)]
   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `FromInputValue<__S>` is not implemented for `ObjectA`
@@ -16,16 +20,20 @@ error[E0277]: the trait bound `ObjectA: FromInputValue<__S>` is not satisfied
   = note: this error originates in the derive macro `juniper::GraphQLInputObject` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `ObjectA: FromInputValue<__S>` is not satisfied
- --> $DIR/derive_incompatible_object.rs:6:10
-  |
-6 | #[derive(juniper::GraphQLInputObject)]
-  |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `FromInputValue<__S>` is not implemented for `ObjectA`
-  |
-  = note: required by `from_input_value`
-  = note: this error originates in the derive macro `juniper::GraphQLInputObject` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/input-object/derive_incompatible_object.rs:6:10
+    |
+6   | #[derive(juniper::GraphQLInputObject)]
+    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `FromInputValue<__S>` is not implemented for `ObjectA`
+    |
+note: required by `from_input_value`
+   --> $WORKSPACE/juniper/src/ast.rs
+    |
+    |     fn from_input_value(v: &InputValue<S>) -> Result<Self, Self::Error>;
+    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    = note: this error originates in the derive macro `juniper::GraphQLInputObject` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0599]: no method named `to_input_value` found for struct `ObjectA` in the current scope
- --> $DIR/derive_incompatible_object.rs:6:10
+ --> fail/input-object/derive_incompatible_object.rs:6:10
   |
 2 | struct ObjectA {
   | -------------- method `to_input_value` not found for this
diff --git a/integration_tests/codegen_fail/fail/input-object/derive_no_fields.stderr b/integration_tests/codegen_fail/fail/input-object/derive_no_fields.stderr
index 883292328..edb0aa99e 100644
--- a/integration_tests/codegen_fail/fail/input-object/derive_no_fields.stderr
+++ b/integration_tests/codegen_fail/fail/input-object/derive_no_fields.stderr
@@ -1,7 +1,8 @@
 error: GraphQL input object expects at least one field
- --> $DIR/derive_no_fields.rs:2:1
+
+  = note: https://spec.graphql.org/June2018/#sec-Input-Objects
+
+ --> fail/input-object/derive_no_fields.rs:2:1
   |
 2 | struct Object {}
-  | ^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Input-Objects
+  | ^^^^^^
diff --git a/integration_tests/codegen_fail/fail/input-object/derive_no_underscore.stderr b/integration_tests/codegen_fail/fail/input-object/derive_no_underscore.stderr
index eb7eb67b5..08e367306 100644
--- a/integration_tests/codegen_fail/fail/input-object/derive_no_underscore.stderr
+++ b/integration_tests/codegen_fail/fail/input-object/derive_no_underscore.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/derive_no_underscore.rs:3:15
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/input-object/derive_no_underscore.rs:3:15
   |
 3 |     #[graphql(name = "__test")]
   |               ^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/input-object/derive_unique_name.stderr b/integration_tests/codegen_fail/fail/input-object/derive_unique_name.stderr
index ccecaf48d..019df45d4 100644
--- a/integration_tests/codegen_fail/fail/input-object/derive_unique_name.stderr
+++ b/integration_tests/codegen_fail/fail/input-object/derive_unique_name.stderr
@@ -1,9 +1,9 @@
 error: GraphQL input object does not allow fields with the same name
- --> $DIR/derive_unique_name.rs:4:5
-  |
-4 | /     #[graphql(name = "test")]
-5 | |     test2: String,
-  | |_________________^
-  |
+
   = help: There is at least one other field with the same name `test`, possibly renamed via the #[graphql] attribute
   = note: https://spec.graphql.org/June2018/#sec-Input-Objects
+
+ --> fail/input-object/derive_unique_name.rs:4:5
+  |
+4 |     #[graphql(name = "test")]
+  |     ^
diff --git a/integration_tests/codegen_fail/fail/interface/argument_double_underscored.stderr b/integration_tests/codegen_fail/fail/interface/argument_double_underscored.stderr
index f06c385cc..b36017e02 100644
--- a/integration_tests/codegen_fail/fail/interface/argument_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/interface/argument_double_underscored.stderr
@@ -1,10 +1,11 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
   --> $DIR/argument_double_underscored.rs:14:18
    |
 14 |     fn id(&self, __num: i32) -> &str {
    |                  ^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Schema
 
 error[E0412]: cannot find type `CharacterValue` in this scope
  --> $DIR/argument_double_underscored.rs:4:18
diff --git a/integration_tests/codegen_fail/fail/interface/argument_non_input_type.stderr b/integration_tests/codegen_fail/fail/interface/argument_non_input_type.stderr
index 131e43e2d..44ae096b8 100644
--- a/integration_tests/codegen_fail/fail/interface/argument_non_input_type.stderr
+++ b/integration_tests/codegen_fail/fail/interface/argument_non_input_type.stderr
@@ -1,14 +1,18 @@
 error[E0277]: the trait bound `ObjA: IsInputType<__S>` is not satisfied
-  --> $DIR/argument_non_input_type.rs:16:1
-   |
-16 | #[graphql_interface(for = ObjA)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsInputType<__S>` is not implemented for `ObjA`
-   |
-   = note: required by `juniper::marker::IsInputType::mark`
-   = note: this error originates in the attribute macro `graphql_interface` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/interface/argument_non_input_type.rs:16:1
+    |
+16  | #[graphql_interface(for = ObjA)]
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsInputType<__S>` is not implemented for `ObjA`
+    |
+note: required by `juniper::marker::IsInputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_interface` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `ObjA: FromInputValue<__S>` is not satisfied
-  --> $DIR/argument_non_input_type.rs:16:1
+  --> fail/interface/argument_non_input_type.rs:16:1
    |
 16 | #[graphql_interface(for = ObjA)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `FromInputValue<__S>` is not implemented for `ObjA`
diff --git a/integration_tests/codegen_fail/fail/interface/downcast_method_conflicts_with_external_downcast_fn.stderr b/integration_tests/codegen_fail/fail/interface/downcast_method_conflicts_with_external_downcast_fn.stderr
index a8abef2df..ce90439b4 100644
--- a/integration_tests/codegen_fail/fail/interface/downcast_method_conflicts_with_external_downcast_fn.stderr
+++ b/integration_tests/codegen_fail/fail/interface/downcast_method_conflicts_with_external_downcast_fn.stderr
@@ -1,11 +1,12 @@
 error: GraphQL interface trait method `as_obja` conflicts with the external downcast function `downcast_obja` declared on the trait to downcast into the implementer type `ObjA`
+
+  = note: https://spec.graphql.org/June2018/#sec-Interfaces
+  = note: use `#[graphql(ignore)]` attribute argument to ignore this trait method for interface implementers downcasting
+
   --> $DIR/downcast_method_conflicts_with_external_downcast_fn.rs:26:5
    |
 26 |     fn as_obja(&self) -> Option<&ObjA>;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Interfaces
-   = note: use `#[graphql(ignore)]` attribute argument to ignore this trait method for interface implementers downcasting
+   |     ^^
 
 error[E0412]: cannot find type `CharacterValue` in this scope
  --> $DIR/downcast_method_conflicts_with_external_downcast_fn.rs:4:18
diff --git a/integration_tests/codegen_fail/fail/interface/downcast_method_wrong_input_args.stderr b/integration_tests/codegen_fail/fail/interface/downcast_method_wrong_input_args.stderr
index 718a0a251..543c8cfff 100644
--- a/integration_tests/codegen_fail/fail/interface/downcast_method_wrong_input_args.stderr
+++ b/integration_tests/codegen_fail/fail/interface/downcast_method_wrong_input_args.stderr
@@ -1,10 +1,11 @@
 error: GraphQL interface expects trait method to accept `&self` only and, optionally, `&Context`
+
+  = note: https://spec.graphql.org/June2018/#sec-Interfaces
+
   --> $DIR/downcast_method_wrong_input_args.rs:10:10
    |
 10 |     fn a(&self, ctx: &(), rand: u8) -> Option<&Human> {
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Interfaces
+   |          ^
 
 error[E0412]: cannot find type `CharacterValue` in this scope
   --> $DIR/downcast_method_wrong_input_args.rs:16:18
diff --git a/integration_tests/codegen_fail/fail/interface/downcast_method_wrong_return_type.stderr b/integration_tests/codegen_fail/fail/interface/downcast_method_wrong_return_type.stderr
index 8c4594950..164c78ccf 100644
--- a/integration_tests/codegen_fail/fail/interface/downcast_method_wrong_return_type.stderr
+++ b/integration_tests/codegen_fail/fail/interface/downcast_method_wrong_return_type.stderr
@@ -1,19 +1,20 @@
 error: GraphQL interface expects trait method return type to be `Option<&ImplementerType>` only
-  --> $DIR/downcast_method_wrong_return_type.rs:10:40
+
+  = note: https://spec.graphql.org/June2018/#sec-Interfaces
+
+  --> fail/interface/downcast_method_wrong_return_type.rs:10:40
    |
 10 |     fn a(&self, ctx: &(), rand: u8) -> &Human {
-   |                                        ^^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Interfaces
+   |                                        ^
 
 error[E0412]: cannot find type `CharacterValue` in this scope
-  --> $DIR/downcast_method_wrong_return_type.rs:16:18
+  --> fail/interface/downcast_method_wrong_return_type.rs:16:18
    |
 16 | #[graphql(impl = CharacterValue)]
    |                  ^^^^^^^^^^^^^^ not found in this scope
 
 error[E0405]: cannot find trait `Character` in this scope
-  --> $DIR/downcast_method_wrong_return_type.rs:22:6
+  --> fail/interface/downcast_method_wrong_return_type.rs:22:6
    |
 22 | impl Character for Human {}
    |      ^^^^^^^^^ not found in this scope
diff --git a/integration_tests/codegen_fail/fail/interface/field_double_underscored.stderr b/integration_tests/codegen_fail/fail/interface/field_double_underscored.stderr
index adebb09f2..fdd492f50 100644
--- a/integration_tests/codegen_fail/fail/interface/field_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/interface/field_double_underscored.stderr
@@ -1,19 +1,20 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-  --> $DIR/field_double_underscored.rs:14:8
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+  --> fail/interface/field_double_underscored.rs:14:8
    |
 14 |     fn __id(&self) -> &str {
    |        ^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Schema
 
 error[E0412]: cannot find type `CharacterValue` in this scope
- --> $DIR/field_double_underscored.rs:4:18
+ --> fail/interface/field_double_underscored.rs:4:18
   |
 4 | #[graphql(impl = CharacterValue)]
   |                  ^^^^^^^^^^^^^^ not found in this scope
 
 error[E0405]: cannot find trait `Character` in this scope
-  --> $DIR/field_double_underscored.rs:10:6
+  --> fail/interface/field_double_underscored.rs:10:6
    |
 10 | impl Character for ObjA {}
    |      ^^^^^^^^^ not found in this scope
diff --git a/integration_tests/codegen_fail/fail/interface/field_non_output_return_type.stderr b/integration_tests/codegen_fail/fail/interface/field_non_output_return_type.stderr
index 0ebe0fa2c..19f45f691 100644
--- a/integration_tests/codegen_fail/fail/interface/field_non_output_return_type.stderr
+++ b/integration_tests/codegen_fail/fail/interface/field_non_output_return_type.stderr
@@ -1,8 +1,12 @@
 error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
-  --> $DIR/field_non_output_return_type.rs:17:1
-   |
-17 | #[graphql_interface(for = ObjA)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
-   |
-   = note: required by `juniper::marker::IsOutputType::mark`
-   = note: this error originates in the attribute macro `graphql_interface` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/interface/field_non_output_return_type.rs:17:1
+    |
+17  | #[graphql_interface(for = ObjA)]
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
+    |
+note: required by `juniper::marker::IsOutputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_interface` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/integration_tests/codegen_fail/fail/interface/fields_duplicate.stderr b/integration_tests/codegen_fail/fail/interface/fields_duplicate.stderr
index db1333863..ff07dbcbb 100644
--- a/integration_tests/codegen_fail/fail/interface/fields_duplicate.stderr
+++ b/integration_tests/codegen_fail/fail/interface/fields_duplicate.stderr
@@ -1,25 +1,20 @@
 error: GraphQL interface must have a different name for each field
-  --> $DIR/fields_duplicate.rs:13:1
-   |
-13 | / trait Character {
-14 | |     fn id(&self) -> &str {
-15 | |         "funA"
-16 | |     }
-...  |
-21 | |     }
-22 | | }
-   | |_^
+
+  = note: https://spec.graphql.org/June2018/#sec-Interfaces
+
+  --> fail/interface/fields_duplicate.rs:13:1
    |
-   = note: https://spec.graphql.org/June2018/#sec-Interfaces
+13 | trait Character {
+   | ^^^^^
 
 error[E0412]: cannot find type `CharacterValue` in this scope
- --> $DIR/fields_duplicate.rs:4:18
+ --> fail/interface/fields_duplicate.rs:4:18
   |
 4 | #[graphql(impl = CharacterValue)]
   |                  ^^^^^^^^^^^^^^ not found in this scope
 
 error[E0405]: cannot find trait `Character` in this scope
-  --> $DIR/fields_duplicate.rs:10:6
+  --> fail/interface/fields_duplicate.rs:10:6
    |
 10 | impl Character for ObjA {}
    |      ^^^^^^^^^ not found in this scope
diff --git a/integration_tests/codegen_fail/fail/interface/implementer_non_object_type.stderr b/integration_tests/codegen_fail/fail/interface/implementer_non_object_type.stderr
index 597171164..d3c55953a 100644
--- a/integration_tests/codegen_fail/fail/interface/implementer_non_object_type.stderr
+++ b/integration_tests/codegen_fail/fail/interface/implementer_non_object_type.stderr
@@ -1,17 +1,25 @@
 error[E0277]: the trait bound `ObjA: GraphQLObject<__S>` is not satisfied
-  --> $DIR/implementer_non_object_type.rs:15:1
+  --> fail/interface/implementer_non_object_type.rs:15:1
    |
 15 | #[graphql_interface(for = ObjA)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `ObjA`
    |
-   = note: required by `juniper::GraphQLObject::mark`
+note: required by `juniper::GraphQLObject::mark`
+  --> $WORKSPACE/juniper/src/types/marker.rs
+   |
+   |     fn mark() {}
+   |     ^^^^^^^^^
    = note: this error originates in the attribute macro `graphql_interface` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `ObjA: IsOutputType<__S>` is not satisfied
-  --> $DIR/implementer_non_object_type.rs:15:1
-   |
-15 | #[graphql_interface(for = ObjA)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjA`
-   |
-   = note: required by `juniper::marker::IsOutputType::mark`
-   = note: this error originates in the attribute macro `graphql_interface` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/interface/implementer_non_object_type.rs:15:1
+    |
+15  | #[graphql_interface(for = ObjA)]
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjA`
+    |
+note: required by `juniper::marker::IsOutputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_interface` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/integration_tests/codegen_fail/fail/interface/name_double_underscored.stderr b/integration_tests/codegen_fail/fail/interface/name_double_underscored.stderr
index de8c6715f..ba46779fc 100644
--- a/integration_tests/codegen_fail/fail/interface/name_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/interface/name_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
  --> $DIR/name_double_underscored.rs:4:7
   |
 4 | trait __Character {
   |       ^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/interface/no_fields.stderr b/integration_tests/codegen_fail/fail/interface/no_fields.stderr
index 367a5e9bc..3d2e4d371 100644
--- a/integration_tests/codegen_fail/fail/interface/no_fields.stderr
+++ b/integration_tests/codegen_fail/fail/interface/no_fields.stderr
@@ -1,10 +1,11 @@
 error: GraphQL interface must have at least one field
+
+  = note: https://spec.graphql.org/June2018/#sec-Interfaces
+
   --> $DIR/no_fields.rs:13:1
    |
 13 | trait Character {}
-   | ^^^^^^^^^^^^^^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Interfaces
+   | ^^^^^
 
 error[E0412]: cannot find type `CharacterValue` in this scope
  --> $DIR/no_fields.rs:4:18
diff --git a/integration_tests/codegen_fail/fail/object/argument_double_underscored.stderr b/integration_tests/codegen_fail/fail/object/argument_double_underscored.stderr
index 433c024e0..f93a398fc 100644
--- a/integration_tests/codegen_fail/fail/object/argument_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/object/argument_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/argument_double_underscored.rs:7:18
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/object/argument_double_underscored.rs:7:18
   |
 7 |     fn id(&self, __num: i32) -> &str {
   |                  ^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/object/argument_non_input_type.stderr b/integration_tests/codegen_fail/fail/object/argument_non_input_type.stderr
index 1a054e5ef..976f8e089 100644
--- a/integration_tests/codegen_fail/fail/object/argument_non_input_type.stderr
+++ b/integration_tests/codegen_fail/fail/object/argument_non_input_type.stderr
@@ -1,14 +1,18 @@
 error[E0277]: the trait bound `ObjA: IsInputType<__S>` is not satisfied
-  --> $DIR/argument_non_input_type.rs:10:1
-   |
-10 | #[graphql_object]
-   | ^^^^^^^^^^^^^^^^^ the trait `IsInputType<__S>` is not implemented for `ObjA`
-   |
-   = note: required by `juniper::marker::IsInputType::mark`
-   = note: this error originates in the attribute macro `graphql_object` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/object/argument_non_input_type.rs:10:1
+    |
+10  | #[graphql_object]
+    | ^^^^^^^^^^^^^^^^^ the trait `IsInputType<__S>` is not implemented for `ObjA`
+    |
+note: required by `juniper::marker::IsInputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_object` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `ObjA: FromInputValue<__S>` is not satisfied
-  --> $DIR/argument_non_input_type.rs:10:1
+  --> fail/object/argument_non_input_type.rs:10:1
    |
 10 | #[graphql_object]
    | ^^^^^^^^^^^^^^^^^ the trait `FromInputValue<__S>` is not implemented for `ObjA`
diff --git a/integration_tests/codegen_fail/fail/object/attr_field_non_output_return_type.stderr b/integration_tests/codegen_fail/fail/object/attr_field_non_output_return_type.stderr
index 9bc4c6bda..4339c20ef 100644
--- a/integration_tests/codegen_fail/fail/object/attr_field_non_output_return_type.stderr
+++ b/integration_tests/codegen_fail/fail/object/attr_field_non_output_return_type.stderr
@@ -1,8 +1,12 @@
 error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
-  --> $DIR/attr_field_non_output_return_type.rs:10:1
-   |
-10 | #[graphql_object]
-   | ^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
-   |
-   = note: required by `juniper::marker::IsOutputType::mark`
-   = note: this error originates in the attribute macro `graphql_object` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/object/attr_field_non_output_return_type.rs:10:1
+    |
+10  | #[graphql_object]
+    | ^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
+    |
+note: required by `juniper::marker::IsOutputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_object` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/integration_tests/codegen_fail/fail/object/attr_fields_duplicate.stderr b/integration_tests/codegen_fail/fail/object/attr_fields_duplicate.stderr
index 468e4cde5..f22b6155d 100644
--- a/integration_tests/codegen_fail/fail/object/attr_fields_duplicate.stderr
+++ b/integration_tests/codegen_fail/fail/object/attr_fields_duplicate.stderr
@@ -1,7 +1,8 @@
 error: GraphQL object must have a different name for each field
- --> $DIR/attr_fields_duplicate.rs:6:6
+
+  = note: https://spec.graphql.org/June2018/#sec-Objects
+
+ --> fail/object/attr_fields_duplicate.rs:6:6
   |
 6 | impl ObjA {
   |      ^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Objects
diff --git a/integration_tests/codegen_fail/fail/object/attr_name_double_underscored.stderr b/integration_tests/codegen_fail/fail/object/attr_name_double_underscored.stderr
index e7bedddbf..323003ab7 100644
--- a/integration_tests/codegen_fail/fail/object/attr_name_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/object/attr_name_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/attr_name_double_underscored.rs:6:6
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/object/attr_name_double_underscored.rs:6:6
   |
 6 | impl __Obj {
   |      ^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/object/attr_no_fields.stderr b/integration_tests/codegen_fail/fail/object/attr_no_fields.stderr
index f783cc91a..35a77ead6 100644
--- a/integration_tests/codegen_fail/fail/object/attr_no_fields.stderr
+++ b/integration_tests/codegen_fail/fail/object/attr_no_fields.stderr
@@ -1,7 +1,8 @@
 error: GraphQL object must have at least one field
- --> $DIR/attr_no_fields.rs:6:6
+
+  = note: https://spec.graphql.org/June2018/#sec-Objects
+
+ --> fail/object/attr_no_fields.rs:6:6
   |
 6 | impl Obj {}
   |      ^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Objects
diff --git a/integration_tests/codegen_fail/fail/object/derive_field_double_underscored.stderr b/integration_tests/codegen_fail/fail/object/derive_field_double_underscored.stderr
index a6f3cb8db..09be8d8e2 100644
--- a/integration_tests/codegen_fail/fail/object/derive_field_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/object/derive_field_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/derive_field_double_underscored.rs:5:5
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/object/derive_field_double_underscored.rs:5:5
   |
 5 |     __test: String,
   |     ^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/object/derive_field_non_output_return_type.stderr b/integration_tests/codegen_fail/fail/object/derive_field_non_output_return_type.stderr
index d112debd2..0a24fe8e9 100644
--- a/integration_tests/codegen_fail/fail/object/derive_field_non_output_return_type.stderr
+++ b/integration_tests/codegen_fail/fail/object/derive_field_non_output_return_type.stderr
@@ -1,8 +1,12 @@
 error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
- --> $DIR/derive_field_non_output_return_type.rs:8:10
-  |
-8 | #[derive(GraphQLObject)]
-  |          ^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
-  |
-  = note: required by `juniper::marker::IsOutputType::mark`
-  = note: this error originates in the derive macro `GraphQLObject` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/object/derive_field_non_output_return_type.rs:8:10
+    |
+8   | #[derive(GraphQLObject)]
+    |          ^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
+    |
+note: required by `juniper::marker::IsOutputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the derive macro `GraphQLObject` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/integration_tests/codegen_fail/fail/object/derive_fields_duplicate.stderr b/integration_tests/codegen_fail/fail/object/derive_fields_duplicate.stderr
index 74004561b..3615a35ca 100644
--- a/integration_tests/codegen_fail/fail/object/derive_fields_duplicate.stderr
+++ b/integration_tests/codegen_fail/fail/object/derive_fields_duplicate.stderr
@@ -1,11 +1,8 @@
 error: GraphQL object must have a different name for each field
- --> $DIR/derive_fields_duplicate.rs:4:1
-  |
-4 | / struct ObjA {
-5 | |     id: String,
-6 | |     #[graphql(name = "id")]
-7 | |     id2: String,
-8 | | }
-  | |_^
-  |
+
   = note: https://spec.graphql.org/June2018/#sec-Objects
+
+ --> fail/object/derive_fields_duplicate.rs:4:1
+  |
+4 | struct ObjA {
+  | ^^^^^^
diff --git a/integration_tests/codegen_fail/fail/object/derive_name_double_underscored.stderr b/integration_tests/codegen_fail/fail/object/derive_name_double_underscored.stderr
index 11eafcef6..eb9dfb6cf 100644
--- a/integration_tests/codegen_fail/fail/object/derive_name_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/object/derive_name_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/derive_name_double_underscored.rs:4:8
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/object/derive_name_double_underscored.rs:4:8
   |
 4 | struct __Obj {
   |        ^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/object/derive_no_fields.stderr b/integration_tests/codegen_fail/fail/object/derive_no_fields.stderr
index 1975c3611..96038236f 100644
--- a/integration_tests/codegen_fail/fail/object/derive_no_fields.stderr
+++ b/integration_tests/codegen_fail/fail/object/derive_no_fields.stderr
@@ -1,7 +1,8 @@
 error: GraphQL object must have at least one field
- --> $DIR/derive_no_fields.rs:4:1
+
+  = note: https://spec.graphql.org/June2018/#sec-Objects
+
+ --> fail/object/derive_no_fields.rs:4:1
   |
 4 | struct Obj {}
-  | ^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Objects
+  | ^^^^^^
diff --git a/integration_tests/codegen_fail/fail/object/derive_wrong_item.stderr b/integration_tests/codegen_fail/fail/object/derive_wrong_item.stderr
index 50680bec9..71b8d0e58 100644
--- a/integration_tests/codegen_fail/fail/object/derive_wrong_item.stderr
+++ b/integration_tests/codegen_fail/fail/object/derive_wrong_item.stderr
@@ -1,5 +1,5 @@
 error: GraphQL object can only be derived for structs
- --> $DIR/derive_wrong_item.rs:4:1
+ --> fail/object/derive_wrong_item.rs:4:1
   |
 4 | enum Character {}
-  | ^^^^^^^^^^^^^^^^^
+  | ^^^^
diff --git a/integration_tests/codegen_fail/fail/subscription/argument_double_underscored.stderr b/integration_tests/codegen_fail/fail/subscription/argument_double_underscored.stderr
index 97d9d6df1..7cc24a2d3 100644
--- a/integration_tests/codegen_fail/fail/subscription/argument_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/subscription/argument_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-  --> $DIR/argument_double_underscored.rs:11:24
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+  --> fail/subscription/argument_double_underscored.rs:11:24
    |
 11 |     async fn id(&self, __num: i32) -> Stream<'static, &'static str> {
    |                        ^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/subscription/argument_non_input_type.stderr b/integration_tests/codegen_fail/fail/subscription/argument_non_input_type.stderr
index 87d4a9ee7..59f35de39 100644
--- a/integration_tests/codegen_fail/fail/subscription/argument_non_input_type.stderr
+++ b/integration_tests/codegen_fail/fail/subscription/argument_non_input_type.stderr
@@ -1,14 +1,18 @@
 error[E0277]: the trait bound `ObjA: IsInputType<__S>` is not satisfied
-  --> $DIR/argument_non_input_type.rs:15:1
-   |
-15 | #[graphql_subscription]
-   | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsInputType<__S>` is not implemented for `ObjA`
-   |
-   = note: required by `juniper::marker::IsInputType::mark`
-   = note: this error originates in the attribute macro `graphql_subscription` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/subscription/argument_non_input_type.rs:15:1
+    |
+15  | #[graphql_subscription]
+    | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsInputType<__S>` is not implemented for `ObjA`
+    |
+note: required by `juniper::marker::IsInputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_subscription` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `ObjA: FromInputValue<__S>` is not satisfied
-  --> $DIR/argument_non_input_type.rs:15:1
+  --> fail/subscription/argument_non_input_type.rs:15:1
    |
 15 | #[graphql_subscription]
    | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `FromInputValue<__S>` is not implemented for `ObjA`
diff --git a/integration_tests/codegen_fail/fail/subscription/field_non_output_return_type.stderr b/integration_tests/codegen_fail/fail/subscription/field_non_output_return_type.stderr
index 84d4cf63b..a4adbdd62 100644
--- a/integration_tests/codegen_fail/fail/subscription/field_non_output_return_type.stderr
+++ b/integration_tests/codegen_fail/fail/subscription/field_non_output_return_type.stderr
@@ -1,8 +1,12 @@
 error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
-  --> $DIR/field_non_output_return_type.rs:15:1
-   |
-15 | #[graphql_subscription]
-   | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
-   |
-   = note: required by `juniper::marker::IsOutputType::mark`
-   = note: this error originates in the attribute macro `graphql_subscription` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/subscription/field_non_output_return_type.rs:15:1
+    |
+15  | #[graphql_subscription]
+    | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
+    |
+note: required by `juniper::marker::IsOutputType::mark`
+   --> $WORKSPACE/juniper/src/types/marker.rs
+    |
+    |     fn mark() {}
+    |     ^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_subscription` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/integration_tests/codegen_fail/fail/subscription/field_not_async.stderr b/integration_tests/codegen_fail/fail/subscription/field_not_async.stderr
index 3e5209c8e..344b56735 100644
--- a/integration_tests/codegen_fail/fail/subscription/field_not_async.stderr
+++ b/integration_tests/codegen_fail/fail/subscription/field_not_async.stderr
@@ -1,8 +1,9 @@
 error: GraphQL object synchronous resolvers are not supported
-  --> $DIR/field_not_async.rs:11:5
+
+  = note: https://spec.graphql.org/June2018/#sec-Objects
+  = note: Specify that this function is async: `async fn foo()`
+
+  --> fail/subscription/field_not_async.rs:11:5
    |
 11 |     fn id(&self) -> Stream<'static, bool> {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Objects
-   = note: Specify that this function is async: `async fn foo()`
+   |     ^^
diff --git a/integration_tests/codegen_fail/fail/subscription/fields_duplicate.stderr b/integration_tests/codegen_fail/fail/subscription/fields_duplicate.stderr
index d9156450c..733dd6dda 100644
--- a/integration_tests/codegen_fail/fail/subscription/fields_duplicate.stderr
+++ b/integration_tests/codegen_fail/fail/subscription/fields_duplicate.stderr
@@ -1,7 +1,8 @@
 error: GraphQL object must have a different name for each field
-  --> $DIR/fields_duplicate.rs:10:6
+
+  = note: https://spec.graphql.org/June2018/#sec-Objects
+
+  --> fail/subscription/fields_duplicate.rs:10:6
    |
 10 | impl ObjA {
    |      ^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Objects
diff --git a/integration_tests/codegen_fail/fail/subscription/name_double_underscored.stderr b/integration_tests/codegen_fail/fail/subscription/name_double_underscored.stderr
index ac1081e35..b93010eac 100644
--- a/integration_tests/codegen_fail/fail/subscription/name_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/subscription/name_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-  --> $DIR/name_double_underscored.rs:10:6
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+  --> fail/subscription/name_double_underscored.rs:10:6
    |
 10 | impl __Obj {
    |      ^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/subscription/no_fields.stderr b/integration_tests/codegen_fail/fail/subscription/no_fields.stderr
index 93b5487f5..8bb828020 100644
--- a/integration_tests/codegen_fail/fail/subscription/no_fields.stderr
+++ b/integration_tests/codegen_fail/fail/subscription/no_fields.stderr
@@ -1,7 +1,8 @@
 error: GraphQL object must have at least one field
- --> $DIR/no_fields.rs:6:6
+
+  = note: https://spec.graphql.org/June2018/#sec-Objects
+
+ --> fail/subscription/no_fields.rs:6:6
   |
 6 | impl Obj {}
   |      ^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Objects
diff --git a/integration_tests/codegen_fail/fail/union/derive_wrong_item.stderr b/integration_tests/codegen_fail/fail/union/derive_wrong_item.stderr
index fdeb15b40..85b57e2c9 100644
--- a/integration_tests/codegen_fail/fail/union/derive_wrong_item.stderr
+++ b/integration_tests/codegen_fail/fail/union/derive_wrong_item.stderr
@@ -1,5 +1,5 @@
 error: GraphQL union can only be derived for enums and structs
- --> $DIR/derive_wrong_item.rs:4:1
+ --> fail/union/derive_wrong_item.rs:4:1
   |
 4 | union Character { id: i32 }
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  | ^^^^^
diff --git a/integration_tests/codegen_fail/fail/union/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.stderr b/integration_tests/codegen_fail/fail/union/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.stderr
index 12957f131..c0f378c36 100644
--- a/integration_tests/codegen_fail/fail/union/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.stderr
+++ b/integration_tests/codegen_fail/fail/union/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.stderr
@@ -1,7 +1,8 @@
 error: GraphQL union variant `Human` already has external resolver function `resolve_fn1` declared on the enum
- --> $DIR/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.rs:6:15
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.rs:6:15
   |
 6 |     #[graphql(with = resolve_fn2)]
   |               ^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
diff --git a/integration_tests/codegen_fail/fail/union/enum_name_double_underscored.stderr b/integration_tests/codegen_fail/fail/union/enum_name_double_underscored.stderr
index df5db23fd..f952d0f83 100644
--- a/integration_tests/codegen_fail/fail/union/enum_name_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/union/enum_name_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/enum_name_double_underscored.rs:4:6
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/union/enum_name_double_underscored.rs:4:6
   |
 4 | enum __Character {
   |      ^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/union/enum_no_fields.stderr b/integration_tests/codegen_fail/fail/union/enum_no_fields.stderr
index 85ea25850..4d7d4f07b 100644
--- a/integration_tests/codegen_fail/fail/union/enum_no_fields.stderr
+++ b/integration_tests/codegen_fail/fail/union/enum_no_fields.stderr
@@ -1,7 +1,8 @@
 error: GraphQL union expects at least one union variant
- --> $DIR/enum_no_fields.rs:4:1
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/enum_no_fields.rs:4:1
   |
 4 | enum Character {}
-  | ^^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
+  | ^^^^
diff --git a/integration_tests/codegen_fail/fail/union/enum_non_object_variant.stderr b/integration_tests/codegen_fail/fail/union/enum_non_object_variant.stderr
index fc7f13fa1..ccfb6325d 100644
--- a/integration_tests/codegen_fail/fail/union/enum_non_object_variant.stderr
+++ b/integration_tests/codegen_fail/fail/union/enum_non_object_variant.stderr
@@ -1,8 +1,12 @@
 error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
- --> $DIR/enum_non_object_variant.rs:9:10
-  |
-9 | #[derive(GraphQLUnion)]
-  |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
-  |
-  = note: required by `juniper::GraphQLObject::mark`
-  = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
+  --> fail/union/enum_non_object_variant.rs:9:10
+   |
+9  | #[derive(GraphQLUnion)]
+   |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
+   |
+note: required by `juniper::GraphQLObject::mark`
+  --> $WORKSPACE/juniper/src/types/marker.rs
+   |
+   |     fn mark() {}
+   |     ^^^^^^^^^
+   = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/integration_tests/codegen_fail/fail/union/enum_same_type_pretty.stderr b/integration_tests/codegen_fail/fail/union/enum_same_type_pretty.stderr
index 65cac9c36..8a6988bf5 100644
--- a/integration_tests/codegen_fail/fail/union/enum_same_type_pretty.stderr
+++ b/integration_tests/codegen_fail/fail/union/enum_same_type_pretty.stderr
@@ -1,10 +1,8 @@
 error: GraphQL union must have a different type for each union variant
- --> $DIR/enum_same_type_pretty.rs:4:1
-  |
-4 | / enum Character {
-5 | |     A(u8),
-6 | |     B(u8),
-7 | | }
-  | |_^
-  |
+
   = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/enum_same_type_pretty.rs:4:1
+  |
+4 | enum Character {
+  | ^^^^
diff --git a/integration_tests/codegen_fail/fail/union/enum_wrong_variant_field.stderr b/integration_tests/codegen_fail/fail/union/enum_wrong_variant_field.stderr
index 4f5def6a9..26497520d 100644
--- a/integration_tests/codegen_fail/fail/union/enum_wrong_variant_field.stderr
+++ b/integration_tests/codegen_fail/fail/union/enum_wrong_variant_field.stderr
@@ -1,15 +1,17 @@
 error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
- --> $DIR/enum_wrong_variant_field.rs:5:5
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/enum_wrong_variant_field.rs:5:5
   |
 5 |     A { human: Human },
   |     ^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
 
 error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
-  --> $DIR/enum_wrong_variant_field.rs:10:6
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+  --> fail/union/enum_wrong_variant_field.rs:10:6
    |
 10 |     A(Human, u8),
    |      ^^^^^^^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Unions
diff --git a/integration_tests/codegen_fail/fail/union/struct_name_double_underscored.stderr b/integration_tests/codegen_fail/fail/union/struct_name_double_underscored.stderr
index 48054c637..c5d3df1e4 100644
--- a/integration_tests/codegen_fail/fail/union/struct_name_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/union/struct_name_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/struct_name_double_underscored.rs:5:8
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/union/struct_name_double_underscored.rs:5:8
   |
 5 | struct __Character;
   |        ^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/union/struct_no_fields.stderr b/integration_tests/codegen_fail/fail/union/struct_no_fields.stderr
index 3d6aaeb2b..d77299544 100644
--- a/integration_tests/codegen_fail/fail/union/struct_no_fields.stderr
+++ b/integration_tests/codegen_fail/fail/union/struct_no_fields.stderr
@@ -1,7 +1,8 @@
 error: GraphQL union expects at least one union variant
- --> $DIR/struct_no_fields.rs:4:1
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/struct_no_fields.rs:4:1
   |
 4 | struct Character;
-  | ^^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
+  | ^^^^^^
diff --git a/integration_tests/codegen_fail/fail/union/struct_non_object_variant.stderr b/integration_tests/codegen_fail/fail/union/struct_non_object_variant.stderr
index 200aeecdf..96df4a97f 100644
--- a/integration_tests/codegen_fail/fail/union/struct_non_object_variant.stderr
+++ b/integration_tests/codegen_fail/fail/union/struct_non_object_variant.stderr
@@ -1,8 +1,12 @@
 error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
- --> $DIR/struct_non_object_variant.rs:9:10
-  |
-9 | #[derive(GraphQLUnion)]
-  |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
-  |
-  = note: required by `juniper::GraphQLObject::mark`
-  = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
+  --> fail/union/struct_non_object_variant.rs:9:10
+   |
+9  | #[derive(GraphQLUnion)]
+   |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
+   |
+note: required by `juniper::GraphQLObject::mark`
+  --> $WORKSPACE/juniper/src/types/marker.rs
+   |
+   |     fn mark() {}
+   |     ^^^^^^^^^
+   = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/integration_tests/codegen_fail/fail/union/trait_fail_infer_context.stderr b/integration_tests/codegen_fail/fail/union/trait_fail_infer_context.stderr
index 9279a9b37..b4eb24816 100644
--- a/integration_tests/codegen_fail/fail/union/trait_fail_infer_context.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_fail_infer_context.stderr
@@ -1,14 +1,18 @@
 error[E0277]: the trait bound `CustomContext: FromContext<SubContext>` is not satisfied
- --> $DIR/trait_fail_infer_context.rs:3:1
-  |
-3 | #[graphql_union]
-  | ^^^^^^^^^^^^^^^^ expected an implementor of trait `FromContext<SubContext>`
-  |
-  = note: required by `juniper::FromContext::from`
-  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
+   --> fail/union/trait_fail_infer_context.rs:3:1
+    |
+3   | #[graphql_union]
+    | ^^^^^^^^^^^^^^^^ expected an implementor of trait `FromContext<SubContext>`
+    |
+note: required by `juniper::FromContext::from`
+   --> $WORKSPACE/juniper/src/executor/mod.rs
+    |
+    |     fn from(value: &T) -> &Self;
+    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0308]: mismatched types
- --> $DIR/trait_fail_infer_context.rs:3:1
+ --> fail/union/trait_fail_infer_context.rs:3:1
   |
 3 | #[graphql_union]
   | ^^^^^^^^^^^^^^^^ expected struct `CustomContext`, found struct `SubContext`
diff --git a/integration_tests/codegen_fail/fail/union/trait_method_conflicts_with_external_resolver_fn.stderr b/integration_tests/codegen_fail/fail/union/trait_method_conflicts_with_external_resolver_fn.stderr
index 6fff37828..197ba1b65 100644
--- a/integration_tests/codegen_fail/fail/union/trait_method_conflicts_with_external_resolver_fn.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_method_conflicts_with_external_resolver_fn.stderr
@@ -1,8 +1,9 @@
 error: GraphQL union trait method `a` conflicts with the external resolver function `some_fn` declared on the trait to resolve the variant type `Human`
- --> $DIR/trait_method_conflicts_with_external_resolver_fn.rs:5:5
-  |
-5 |     fn a(&self) -> Option<&Human>;
-  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |
+
   = note: https://spec.graphql.org/June2018/#sec-Unions
   = note: use `#[graphql(ignore)]` attribute to ignore this trait method for union variants resolution
+
+ --> fail/union/trait_method_conflicts_with_external_resolver_fn.rs:5:5
+  |
+5 |     fn a(&self) -> Option<&Human>;
+  |     ^^
diff --git a/integration_tests/codegen_fail/fail/union/trait_name_double_underscored.stderr b/integration_tests/codegen_fail/fail/union/trait_name_double_underscored.stderr
index d010fee27..3faaa193e 100644
--- a/integration_tests/codegen_fail/fail/union/trait_name_double_underscored.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_name_double_underscored.stderr
@@ -1,7 +1,8 @@
 error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/trait_name_double_underscored.rs:4:7
+
+  = note: https://spec.graphql.org/June2018/#sec-Schema
+
+ --> fail/union/trait_name_double_underscored.rs:4:7
   |
 4 | trait __Character {
   |       ^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
diff --git a/integration_tests/codegen_fail/fail/union/trait_no_fields.stderr b/integration_tests/codegen_fail/fail/union/trait_no_fields.stderr
index 8261623dc..6bc9e4234 100644
--- a/integration_tests/codegen_fail/fail/union/trait_no_fields.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_no_fields.stderr
@@ -1,7 +1,8 @@
 error: GraphQL union expects at least one union variant
- --> $DIR/trait_no_fields.rs:4:1
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/trait_no_fields.rs:4:1
   |
 4 | trait Character {}
-  | ^^^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
+  | ^^^^^
diff --git a/integration_tests/codegen_fail/fail/union/trait_non_object_variant.stderr b/integration_tests/codegen_fail/fail/union/trait_non_object_variant.stderr
index e9ac7cdb7..5697644cc 100644
--- a/integration_tests/codegen_fail/fail/union/trait_non_object_variant.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_non_object_variant.stderr
@@ -1,8 +1,12 @@
 error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
- --> $DIR/trait_non_object_variant.rs:9:1
-  |
-9 | #[graphql_union]
-  | ^^^^^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
-  |
-  = note: required by `juniper::GraphQLObject::mark`
-  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
+  --> fail/union/trait_non_object_variant.rs:9:1
+   |
+9  | #[graphql_union]
+   | ^^^^^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
+   |
+note: required by `juniper::GraphQLObject::mark`
+  --> $WORKSPACE/juniper/src/types/marker.rs
+   |
+   |     fn mark() {}
+   |     ^^^^^^^^^
+   = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/integration_tests/codegen_fail/fail/union/trait_same_type_pretty.stderr b/integration_tests/codegen_fail/fail/union/trait_same_type_pretty.stderr
index f899e3075..490980167 100644
--- a/integration_tests/codegen_fail/fail/union/trait_same_type_pretty.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_same_type_pretty.stderr
@@ -1,10 +1,8 @@
 error: GraphQL union must have a different type for each union variant
- --> $DIR/trait_same_type_pretty.rs:4:1
-  |
-4 | / trait Character {
-5 | |     fn a(&self) -> Option<&u8>;
-6 | |     fn b(&self) -> Option<&u8>;
-7 | | }
-  | |_^
-  |
+
   = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/trait_same_type_pretty.rs:4:1
+  |
+4 | trait Character {
+  | ^^^^^
diff --git a/integration_tests/codegen_fail/fail/union/trait_with_attr_on_method.stderr b/integration_tests/codegen_fail/fail/union/trait_with_attr_on_method.stderr
index 427163a8b..e49387cd0 100644
--- a/integration_tests/codegen_fail/fail/union/trait_with_attr_on_method.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_with_attr_on_method.stderr
@@ -1,8 +1,9 @@
 error: GraphQL union cannot use #[graphql(with = ...)] attribute on a trait method
- --> $DIR/trait_with_attr_on_method.rs:5:15
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+  = note: instead use #[graphql(ignore)] on the method with #[graphql_union(on ... = ...)] on the trait itself
+
+ --> fail/union/trait_with_attr_on_method.rs:5:15
   |
 5 |     #[graphql(with = something)]
   |               ^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-  = note: instead use #[graphql(ignore)] on the method with #[graphql_union(on ... = ...)] on the trait itself
diff --git a/integration_tests/codegen_fail/fail/union/trait_wrong_method_input_args.stderr b/integration_tests/codegen_fail/fail/union/trait_wrong_method_input_args.stderr
index 9b2fa2d85..f32098957 100644
--- a/integration_tests/codegen_fail/fail/union/trait_wrong_method_input_args.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_wrong_method_input_args.stderr
@@ -1,7 +1,8 @@
 error: GraphQL union expects trait method to accept `&self` only and, optionally, `&Context`
- --> $DIR/trait_wrong_method_input_args.rs:5:10
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/trait_wrong_method_input_args.rs:5:10
   |
 5 |     fn a(&self, ctx: &(), rand: u8) -> Option<&Human>;
-  |          ^^^^^^^^^^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
+  |          ^
diff --git a/integration_tests/codegen_fail/fail/union/trait_wrong_method_return_type.stderr b/integration_tests/codegen_fail/fail/union/trait_wrong_method_return_type.stderr
index bbc40568a..9c0dd5b95 100644
--- a/integration_tests/codegen_fail/fail/union/trait_wrong_method_return_type.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_wrong_method_return_type.stderr
@@ -1,7 +1,8 @@
 error: GraphQL union expects trait method return type to be `Option<&VariantType>` only
- --> $DIR/trait_wrong_method_return_type.rs:5:20
+
+  = note: https://spec.graphql.org/June2018/#sec-Unions
+
+ --> fail/union/trait_wrong_method_return_type.rs:5:20
   |
 5 |     fn a(&self) -> &Human;
-  |                    ^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
+  |                    ^
diff --git a/juniper_codegen/src/lib.rs b/juniper_codegen/src/lib.rs
index f4f3cc475..a7bdf882e 100644
--- a/juniper_codegen/src/lib.rs
+++ b/juniper_codegen/src/lib.rs
@@ -233,7 +233,7 @@ pub fn derive_scalar_value(input: TokenStream) -> TokenStream {
 ///     fn from_input_value(value: &juniper::InputValue) -> Result<UserID, juniper::FieldError> {
 ///         Ok(value.as_string_value()
 ///             .map(|s| UserID(s.to_owned()))
-///             .ok_or_else(|| format!("Expected String, found: {}", v))?)
+///             .ok_or_else(|| format!("Expected String, found: {}", value))?)
 ///     }
 ///
 ///     fn from_str<'a>(value: juniper::ScalarToken<'a>) -> juniper::ParseScalarResult<'a, S> {

From 135024535d690e6819599a3ac5b64e56041ef288 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Wed, 1 Dec 2021 15:37:40 +0300
Subject: [PATCH 08/25] Fix book example and docs

---
 docs/book/content/types/scalars.md        |  15 +-
 err.txt                                   | 836 ----------------------
 integration_tests/async_await/src/main.rs | 132 ++--
 juniper/src/ast.rs                        |   2 +
 4 files changed, 78 insertions(+), 907 deletions(-)
 delete mode 100644 err.txt

diff --git a/docs/book/content/types/scalars.md b/docs/book/content/types/scalars.md
index 515815776..c6ce47134 100644
--- a/docs/book/content/types/scalars.md
+++ b/docs/book/content/types/scalars.md
@@ -113,8 +113,8 @@ The example below is used just for illustration.
 #        }
 #    }
 # }
-
-use juniper::{Value, ParseScalarResult, ParseScalarValue};
+#
+use juniper::{FieldError, Value, ParseScalarResult, ParseScalarValue};
 use date::Date;
 
 #[juniper::graphql_scalar(description = "Date")]
@@ -128,10 +128,11 @@ where
     }
 
     // Define how to parse a primitive type into your custom scalar.
-    fn from_input_value(v: &InputValue) -> Option<Date> {
-        v.as_scalar_value()
-        .and_then(|v| v.as_str())
-        .and_then(|s| s.parse().ok())
+    fn from_input_value(v: &InputValue) -> Result<Date, FieldError<S>> {
+        v.as_string_value()
+        .ok_or_else(|| format!("Expected String, found: {}", v))
+        .and_then(|s| s.parse().map_err(|e| format!("Failed to parse Date: {}", e)))
+        .map_err(Into::into)
     }
 
     // Define how to parse a string value.
@@ -139,6 +140,6 @@ where
         <String as ParseScalarValue<S>>::from_str(value)
     }
 }
-
+#
 # fn main() {}
 ```
diff --git a/err.txt b/err.txt
deleted file mode 100644
index e397bf1d6..000000000
--- a/err.txt
+++ /dev/null
@@ -1,836 +0,0 @@
-/Users/work/.cargo/bin/cargo +stable test --color=always -p juniper_codegen_tests --all-features --no-fail-fast -- --format=json -Z unstable-options --show-output
-Testing started at 15:02 ...
-    Finished test [unoptimized + debuginfo] target(s) in 0.20s
-     Running unittests (/Users/work/Work/juniper/target/debug/deps/juniper_codegen_tests-0ab20148dc3374c3)
-    Checking juniper_codegen_tests-tests v0.0.0 (/Users/work/Work/juniper/target/tests/juniper_codegen_tests)
-    Finished dev [unoptimized + debuginfo] target(s) in 0.28s
-
-
-test fail/interface/field_double_underscored.rs ... ok
-test fail/interface/implementers_duplicate_pretty.rs ... ok
-test fail/interface/downcast_method_wrong_input_args.rs ... ok
-test fail/interface/argument_wrong_default_array.rs ... ok
-test fail/interface/wrong_item.rs ... ok
-test fail/interface/name_double_underscored.rs ... ok
-test fail/interface/argument_double_underscored.rs ... ok
-test fail/interface/argument_non_input_type.rs ... ok
-test fail/interface/downcast_method_conflicts_with_external_downcast_fn.rs ... ok
-test fail/interface/no_fields.rs ... ok
-test fail/interface/field_non_output_return_type.rs ... ok
-test fail/interface/implementers_duplicate_ugly.rs ... ok
-test fail/interface/downcast_method_wrong_return_type.rs ... ok
-test fail/interface/fields_duplicate.rs ... ok
-test fail/interface/implementer_non_object_type.rs ... ok
-test fail/input-object/derive_no_fields.rs ... ok
-test fail/input-object/derive_unique_name.rs ... ok
-test fail/input-object/derive_no_underscore.rs ... ok
-test fail/input-object/derive_incompatible_object.rs ... ok
-test fail/enum/derive_no_fields.rs ... ok
-test fail/subscription/field_double_underscored.rs ... ok
-test fail/subscription/field_not_async.rs ... ok
-test fail/subscription/argument_wrong_default_array.rs ... ok
-test fail/subscription/wrong_item.rs ... ok
-test fail/subscription/name_double_underscored.rs ... ok
-test fail/subscription/argument_double_underscored.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-
-  --> fail/subscription/argument_double_underscored.rs:11:24
-   |
-11 |     async fn id(&self, __num: i32) -> Stream<'static, &'static str> {
-   |
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-
-  --> fail/subscription/argument_double_underscored.rs:11:24
-   |
-11 |     async fn id(&self, __num: i32) -> Stream<'static, &'static str> {
-   |                        ^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/subscription/argument_non_input_type.rs ... ok
-test fail/subscription/no_fields.rs ... ok
-test fail/subscription/field_non_output_return_type.rs ... ok
-test fail/subscription/fields_duplicate.rs ... ok
-test fail/object/derive_field_double_underscored.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/derive_field_double_underscored.rs:5:5
-  |
-5 |     __test: String,
-  |     ^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-
- --> fail/object/derive_field_double_underscored.rs:5:5
-  |
-5 |     __test: String,
-  |     ^^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/object/derive_no_fields.rs ... ok
-test fail/object/derive_wrong_item.rs ... ok
-test fail/object/attr_fields_duplicate.rs ... ok
-test fail/object/argument_wrong_default_array.rs ... ok
-test fail/object/argument_double_underscored.rs ... ok
-test fail/object/argument_non_input_type.rs ... ok
-test fail/object/attr_no_fields.rs ... { "type": "test", "event": "timeout", "name": "test_failing_compiliation" }
-ok
-test fail/object/attr_name_double_underscored.rs ... ok
-test fail/object/derive_name_double_underscored.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-
- --> fail/object/derive_field_double_underscored.rs:5:5
-  |
-5 |     __test: String,
-  |     ^^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-
- --> fail/object/derive_name_double_underscored.rs:4:8
-  |
-4 | struct __Obj {
-  |        ^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/object/derive_fields_duplicate.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL object must have a different name for each field
- --> $DIR/derive_fields_duplicate.rs:4:1
-  |
-4 | / struct ObjA {
-5 | |     id: String,
-6 | |     #[graphql(name = "id")]
-7 | |     id2: String,
-8 | | }
-  | |_^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Objects
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL object must have a different name for each field
-
-  = note: https://spec.graphql.org/June2018/#sec-Objects
-
- --> fail/object/derive_fields_duplicate.rs:4:1
-  |
-4 | struct ObjA {
-  | ^^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/object/attr_wrong_item.rs ... ok
-test fail/object/attr_field_non_output_return_type.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
-  --> $DIR/attr_field_non_output_return_type.rs:10:1
-   |
-10 | #[graphql_object]
-   | ^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
-   |
-   = note: required by `juniper::marker::IsOutputType::mark`
-   = note: this error originates in the attribute macro `graphql_object` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
-   --> fail/object/attr_field_non_output_return_type.rs:10:1
-    |
-10  | #[graphql_object]
-    | ^^^^^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
-    |
-note: required by `juniper::marker::IsOutputType::mark`
-   --> $WORKSPACE/juniper/src/types/marker.rs
-    |
-    |     fn mark() {}
-    |     ^^^^^^^^^
-    = note: this error originates in the attribute macro `graphql_object` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/object/attr_field_double_underscored.rs ... ok
-test fail/object/derive_field_non_output_return_type.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
- --> $DIR/derive_field_non_output_return_type.rs:8:10
-  |
-8 | #[derive(GraphQLObject)]
-  |          ^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
-  |
-  = note: required by `juniper::marker::IsOutputType::mark`
-  = note: this error originates in the derive macro `GraphQLObject` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `ObjB: IsOutputType<__S>` is not satisfied
-   --> fail/object/derive_field_non_output_return_type.rs:8:10
-    |
-8   | #[derive(GraphQLObject)]
-    |          ^^^^^^^^^^^^^ the trait `IsOutputType<__S>` is not implemented for `ObjB`
-    |
-note: required by `juniper::marker::IsOutputType::mark`
-   --> $WORKSPACE/juniper/src/types/marker.rs
-    |
-    |     fn mark() {}
-    |     ^^^^^^^^^
-    = note: this error originates in the derive macro `GraphQLObject` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/enum_wrong_variant_field.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
- --> $DIR/enum_wrong_variant_field.rs:5:5
-  |
-5 |     A { human: Human },
-  |     ^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
-error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
-  --> $DIR/enum_wrong_variant_field.rs:10:6
-   |
-10 |     A(Human, u8),
-   |      ^^^^^^^^^^^
-   |
-   = note: https://spec.graphql.org/June2018/#sec-Unions
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
- --> fail/union/enum_wrong_variant_field.rs:5:5
-  |
-5 |     A { human: Human },
-  |     ^
-
-error: GraphQL union enum allows only unnamed variants with a single field, e.g. `Some(T)`
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
-  --> fail/union/enum_wrong_variant_field.rs:10:6
-   |
-10 |     A(Human, u8),
-   |      ^^^^^^^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/struct_non_object_variant.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
- --> $DIR/struct_non_object_variant.rs:9:10
-  |
-9 | #[derive(GraphQLUnion)]
-  |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
-  |
-  = note: required by `juniper::GraphQLObject::mark`
-  = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
-  --> fail/union/struct_non_object_variant.rs:9:10
-   |
-9  | #[derive(GraphQLUnion)]
-   |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
-   |
-note: required by `juniper::GraphQLObject::mark`
-  --> $WORKSPACE/juniper/src/types/marker.rs
-   |
-   |     fn mark() {}
-   |     ^^^^^^^^^
-   = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/struct_same_type_pretty.rs ... ok
-test fail/union/trait_fail_infer_context.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `CustomContext: FromContext<SubContext>` is not satisfied
- --> $DIR/trait_fail_infer_context.rs:3:1
-  |
-3 | #[graphql_union]
-  | ^^^^^^^^^^^^^^^^ expected an implementor of trait `FromContext<SubContext>`
-  |
-  = note: required by `juniper::FromContext::from`
-  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error[E0308]: mismatched types
- --> $DIR/trait_fail_infer_context.rs:3:1
-  |
-3 | #[graphql_union]
-  | ^^^^^^^^^^^^^^^^ expected struct `CustomContext`, found struct `SubContext`
-  |
-  = note: expected reference `&CustomContext`
-             found reference `&SubContext`
-  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `CustomContext: FromContext<SubContext>` is not satisfied
-   --> fail/union/trait_fail_infer_context.rs:3:1
-    |
-3   | #[graphql_union]
-    | ^^^^^^^^^^^^^^^^ expected an implementor of trait `FromContext<SubContext>`
-    |
-note: required by `juniper::FromContext::from`
-   --> $WORKSPACE/juniper/src/executor/mod.rs
-    |
-    |     fn from(value: &T) -> &Self;
-    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-    = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error[E0308]: mismatched types
- --> fail/union/trait_fail_infer_context.rs:3:1
-  |
-3 | #[graphql_union]
-  | ^^^^^^^^^^^^^^^^ expected struct `CustomContext`, found struct `SubContext`
-  |
-  = note: expected reference `&CustomContext`
-             found reference `&SubContext`
-  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/derive_wrong_item.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union can only be derived for enums and structs
- --> $DIR/derive_wrong_item.rs:4:1
-  |
-4 | union Character { id: i32 }
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union can only be derived for enums and structs
- --> fail/union/derive_wrong_item.rs:4:1
-  |
-4 | union Character { id: i32 }
-  | ^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/enum_no_fields.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects at least one union variant
- --> $DIR/enum_no_fields.rs:4:1
-  |
-4 | enum Character {}
-  | ^^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects at least one union variant
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
- --> fail/union/enum_no_fields.rs:4:1
-  |
-4 | enum Character {}
-  | ^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/enum_same_type_pretty.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union must have a different type for each union variant
- --> $DIR/enum_same_type_pretty.rs:4:1
-  |
-4 | / enum Character {
-5 | |     A(u8),
-6 | |     B(u8),
-7 | | }
-  | |_^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union must have a different type for each union variant
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
- --> fail/union/enum_same_type_pretty.rs:4:1
-  |
-4 | enum Character {
-  | ^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/trait_no_fields.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects at least one union variant
- --> $DIR/trait_no_fields.rs:4:1
-  |
-4 | trait Character {}
-  | ^^^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects at least one union variant
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
- --> fail/union/trait_no_fields.rs:4:1
-  |
-4 | trait Character {}
-  | ^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/enum_same_type_ugly.rs ... ok
-test fail/union/trait_same_type_ugly.rs ... ok
-test fail/union/enum_non_object_variant.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
- --> $DIR/enum_non_object_variant.rs:9:10
-  |
-9 | #[derive(GraphQLUnion)]
-  |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
-  |
-  = note: required by `juniper::GraphQLObject::mark`
-  = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
-  --> fail/union/enum_non_object_variant.rs:9:10
-   |
-9  | #[derive(GraphQLUnion)]
-   |          ^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
-   |
-note: required by `juniper::GraphQLObject::mark`
-  --> $WORKSPACE/juniper/src/types/marker.rs
-   |
-   |     fn mark() {}
-   |     ^^^^^^^^^
-   = note: this error originates in the derive macro `GraphQLUnion` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/trait_with_attr_on_method.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union cannot use #[graphql(with = ...)] attribute on a trait method
- --> $DIR/trait_with_attr_on_method.rs:5:15
-  |
-5 |     #[graphql(with = something)]
-  |               ^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-  = note: instead use #[graphql(ignore)] on the method with #[graphql_union(on ... = ...)] on the trait itself
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union cannot use #[graphql(with = ...)] attribute on a trait method
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-  = note: instead use #[graphql(ignore)] on the method with #[graphql_union(on ... = ...)] on the trait itself
-
- --> fail/union/trait_with_attr_on_method.rs:5:15
-  |
-5 |     #[graphql(with = something)]
-  |               ^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/trait_wrong_method_input_args.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects trait method to accept `&self` only and, optionally, `&Context`
- --> $DIR/trait_wrong_method_input_args.rs:5:10
-  |
-5 |     fn a(&self, ctx: &(), rand: u8) -> Option<&Human>;
-  |          ^^^^^^^^^^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects trait method to accept `&self` only and, optionally, `&Context`
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
- --> fail/union/trait_wrong_method_input_args.rs:5:10
-  |
-5 |     fn a(&self, ctx: &(), rand: u8) -> Option<&Human>;
-  |          ^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/trait_name_double_underscored.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/trait_name_double_underscored.rs:4:7
-  |
-4 | trait __Character {
-  |       ^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-
- --> fail/union/trait_name_double_underscored.rs:4:7
-  |
-4 | trait __Character {
-  |       ^^^^^^^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union variant `Human` already has external resolver function `resolve_fn1` declared on the enum
- --> $DIR/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.rs:6:15
-  |
-6 |     #[graphql(with = resolve_fn2)]
-  |               ^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union variant `Human` already has external resolver function `resolve_fn1` declared on the enum
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
- --> fail/union/enum_external_resolver_fn_conflicts_with_variant_external_resolver_fn.rs:6:15
-  |
-6 |     #[graphql(with = resolve_fn2)]
-  |               ^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/trait_same_type_pretty.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union must have a different type for each union variant
- --> $DIR/trait_same_type_pretty.rs:4:1
-  |
-4 | / trait Character {
-5 | |     fn a(&self) -> Option<&u8>;
-6 | |     fn b(&self) -> Option<&u8>;
-7 | | }
-  | |_^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union must have a different type for each union variant
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
- --> fail/union/trait_same_type_pretty.rs:4:1
-  |
-4 | trait Character {
-  | ^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/attr_wrong_item.rs ... ok
-test fail/union/struct_no_fields.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects at least one union variant
- --> $DIR/struct_no_fields.rs:4:1
-  |
-4 | struct Character;
-  | ^^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects at least one union variant
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
- --> fail/union/struct_no_fields.rs:4:1
-  |
-4 | struct Character;
-  | ^^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/struct_name_double_underscored.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/struct_name_double_underscored.rs:5:8
-  |
-5 | struct __Character;
-  |        ^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-
- --> fail/union/struct_name_double_underscored.rs:5:8
-  |
-5 | struct __Character;
-  |        ^^^^^^^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/trait_method_conflicts_with_external_resolver_fn.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union trait method `a` conflicts with the external resolver function `some_fn` declared on the trait to resolve the variant type `Human`
- --> $DIR/trait_method_conflicts_with_external_resolver_fn.rs:5:5
-  |
-5 |     fn a(&self) -> Option<&Human>;
-  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-  = note: use `#[graphql(ignore)]` attribute to ignore this trait method for union variants resolution
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union trait method `a` conflicts with the external resolver function `some_fn` declared on the trait to resolve the variant type `Human`
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-  = note: use `#[graphql(ignore)]` attribute to ignore this trait method for union variants resolution
-
- --> fail/union/trait_method_conflicts_with_external_resolver_fn.rs:5:5
-  |
-5 |     fn a(&self) -> Option<&Human>;
-  |     ^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/enum_name_double_underscored.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
- --> $DIR/enum_name_double_underscored.rs:4:6
-  |
-4 | enum __Character {
-  |      ^^^^^^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: All types and directives defined within a schema must not have a name which begins with `__` (two underscores), as this is used exclusively by GraphQL’s introspection system.
-
-  = note: https://spec.graphql.org/June2018/#sec-Schema
-
- --> fail/union/enum_name_double_underscored.rs:4:6
-  |
-4 | enum __Character {
-  |      ^^^^^^^^^^^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/trait_non_object_variant.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
- --> $DIR/trait_non_object_variant.rs:9:1
-  |
-9 | #[graphql_union]
-  | ^^^^^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
-  |
-  = note: required by `juniper::GraphQLObject::mark`
-  = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error[E0277]: the trait bound `Test: GraphQLObject<__S>` is not satisfied
-  --> fail/union/trait_non_object_variant.rs:9:1
-   |
-9  | #[graphql_union]
-   | ^^^^^^^^^^^^^^^^ the trait `GraphQLObject<__S>` is not implemented for `Test`
-   |
-note: required by `juniper::GraphQLObject::mark`
-  --> $WORKSPACE/juniper/src/types/marker.rs
-   |
-   |     fn mark() {}
-   |     ^^^^^^^^^
-   = note: this error originates in the attribute macro `graphql_union` (in Nightly builds, run with -Z macro-backtrace for more info)
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-test fail/union/struct_same_type_ugly.rs ... ok
-test fail/union/trait_wrong_method_return_type.rs ... mismatch
-
-EXPECTED:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects trait method return type to be `Option<&VariantType>` only
- --> $DIR/trait_wrong_method_return_type.rs:5:20
-  |
-5 |     fn a(&self) -> &Human;
-  |                    ^^^^^^
-  |
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-
-ACTUAL OUTPUT:
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-error: GraphQL union expects trait method return type to be `Option<&VariantType>` only
-
-  = note: https://spec.graphql.org/June2018/#sec-Unions
-
- --> fail/union/trait_wrong_method_return_type.rs:5:20
-  |
-5 |     fn a(&self) -> &Human;
-  |                    ^
-┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
-note: If the actual output is the correct output you can bless it by rerunning
-      your test with the environment variable TRYBUILD=overwrite
-
-
-
-
-25 of 69 tests failed
-thread 'test_failing_compiliation' panicked at '25 of 69 tests failed', /Users/work/.cargo/registry/src/git.colasdn.top-1ecc6299db9ec823/trybuild-1.0.52/src/run.rs:74:13
-stack backtrace:
-   0: rust_begin_unwind
-             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/std/src/panicking.rs:517:5
-   1: std::panicking::begin_panic_fmt
-             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/std/src/panicking.rs:460:5
-   2: trybuild::run::<impl trybuild::Runner>::run
-             at /Users/work/.cargo/registry/src/git.colasdn.top-1ecc6299db9ec823/trybuild-1.0.52/src/run.rs:74:13
-   3: <trybuild::TestCases as core::ops::drop::Drop>::drop
-             at /Users/work/.cargo/registry/src/git.colasdn.top-1ecc6299db9ec823/trybuild-1.0.52/src/lib.rs:306:13
-   4: core::ptr::drop_in_place<trybuild::TestCases>
-             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/core/src/ptr/mod.rs:188:1
-   5: juniper_codegen_tests::test_failing_compiliation
-             at ./src/lib.rs:38:1
-   6: juniper_codegen_tests::test_failing_compiliation::{{closure}}
-             at ./src/lib.rs:28:1
-   7: core::ops::function::FnOnce::call_once
-             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/core/src/ops/function.rs:227:5
-   8: core::ops::function::FnOnce::call_once
-             at /rustc/59eed8a2aac0230a8b53e89d4e99d55912ba6b35/library/core/src/ops/function.rs:227:5
-note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
-
-   Doc-tests juniper_codegen_tests
-error: test failed, to rerun pass '-p juniper_codegen_tests --lib'
-
-Process finished with exit code 101
diff --git a/integration_tests/async_await/src/main.rs b/integration_tests/async_await/src/main.rs
index cf58f90f0..076739446 100644
--- a/integration_tests/async_await/src/main.rs
+++ b/integration_tests/async_await/src/main.rs
@@ -1,7 +1,4 @@
-use juniper::{
-    graphql_object, graphql_value, EmptyMutation, EmptySubscription, GraphQLEnum, GraphQLError,
-    RootNode, Value,
-};
+use juniper::{graphql_object, GraphQLEnum};
 
 #[derive(GraphQLEnum)]
 enum UserKind {
@@ -73,10 +70,18 @@ impl Query {
     }
 }
 
-#[tokio::test]
-async fn async_simple() {
-    let schema = RootNode::new(Query, EmptyMutation::new(), EmptySubscription::new());
-    let doc = r#"
+fn main() {}
+
+#[cfg(test)]
+mod tests {
+    use juniper::{graphql_value, EmptyMutation, EmptySubscription, GraphQLError, RootNode, Value};
+
+    use super::Query;
+
+    #[tokio::test]
+    async fn async_simple() {
+        let schema = RootNode::new(Query, EmptyMutation::new(), EmptySubscription::new());
+        let doc = r#"
         query {
             fieldSync
             fieldAsyncPlain
@@ -89,35 +94,35 @@ async fn async_simple() {
         }
     "#;
 
-    let vars = Default::default();
-    let (res, errs) = juniper::execute(doc, None, &schema, &vars, &())
-        .await
-        .unwrap();
+        let vars = Default::default();
+        let (res, errs) = juniper::execute(doc, None, &schema, &vars, &())
+            .await
+            .unwrap();
 
-    assert!(errs.is_empty());
+        assert!(errs.is_empty());
 
-    let obj = res.into_object().unwrap();
-    let value = Value::Object(obj);
+        let obj = res.into_object().unwrap();
+        let value = Value::Object(obj);
 
-    assert_eq!(
-        value,
-        graphql_value!({
-            "delayed": true,
-            "fieldAsyncPlain": "field_async_plain",
-            "fieldSync": "field_sync",
-            "user": {
+        assert_eq!(
+            value,
+            graphql_value!({
                 "delayed": true,
-                "kind": "USER",
-                "name": "user1",
-            },
-        }),
-    );
-}
+                "fieldAsyncPlain": "field_async_plain",
+                "fieldSync": "field_sync",
+                "user": {
+                    "delayed": true,
+                    "kind": "USER",
+                    "name": "user1",
+                },
+            }),
+        );
+    }
 
-#[tokio::test]
-async fn async_field_validation_error() {
-    let schema = RootNode::new(Query, EmptyMutation::new(), EmptySubscription::new());
-    let doc = r#"
+    #[tokio::test]
+    async fn async_field_validation_error() {
+        let schema = RootNode::new(Query, EmptyMutation::new(), EmptySubscription::new());
+        let doc = r#"
         query {
             nonExistentField
             fieldSync
@@ -131,37 +136,36 @@ async fn async_field_validation_error() {
         }
     "#;
 
-    let vars = Default::default();
-    let result = juniper::execute(doc, None, &schema, &vars, &()).await;
-    assert!(result.is_err());
+        let vars = Default::default();
+        let result = juniper::execute(doc, None, &schema, &vars, &()).await;
+        assert!(result.is_err());
 
-    let error = result.err().unwrap();
-    let is_validation_error = match error {
-        GraphQLError::ValidationError(_) => true,
-        _ => false,
-    };
-    assert!(is_validation_error);
-}
-
-// FIXME: test seems broken by design, re-enable later
-// #[tokio::test]
-// async fn resolve_into_stream_validation_error() {
-//     let schema = RootNode::new(Query, EmptyMutation::new(), EmptySubscription::new());
-//     let doc = r#"
-//         subscription {
-//             nonExistent
-//         }
-//     "#;
-//     let vars = Default::default();
-//     let result = juniper::resolve_into_stream(doc, None, &schema, &vars, &()).await;
-//     assert!(result.is_err());
-
-//     let error = result.err().unwrap();
-//     let is_validation_error = match error {
-//         GraphQLError::ValidationError(_) => true,
-//         _ => false,
-//     };
-//     assert!(is_validation_error);
-// }
+        let error = result.err().unwrap();
+        let is_validation_error = match error {
+            GraphQLError::ValidationError(_) => true,
+            _ => false,
+        };
+        assert!(is_validation_error);
+    }
 
-fn main() {}
+    // FIXME: test seems broken by design, re-enable later
+    // #[tokio::test]
+    // async fn resolve_into_stream_validation_error() {
+    //     let schema = RootNode::new(Query, EmptyMutation::new(), EmptySubscription::new());
+    //     let doc = r#"
+    //         subscription {
+    //             nonExistent
+    //         }
+    //     "#;
+    //     let vars = Default::default();
+    //     let result = juniper::resolve_into_stream(doc, None, &schema, &vars, &()).await;
+    //     assert!(result.is_err());
+
+    //     let error = result.err().unwrap();
+    //     let is_validation_error = match error {
+    //         GraphQLError::ValidationError(_) => true,
+    //         _ => false,
+    //     };
+    //     assert!(is_validation_error);
+    // }
+}
diff --git a/juniper/src/ast.rs b/juniper/src/ast.rs
index 027836173..3c5971d26 100644
--- a/juniper/src/ast.rs
+++ b/juniper/src/ast.rs
@@ -168,6 +168,8 @@ pub trait FromInputValue<S = DefaultScalarValue>: Sized {
     ///
     /// Thus not restricted, it should be convertible with [`IntoFieldError`] to
     /// fit well into the library machinery.
+    ///
+    /// [`IntoFieldError`]: crate::IntoFieldError
     type Error;
 
     /// Performs the conversion.

From ea2fe645ff7d7e0d12d7c86aeb781cb74120cdd3 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Wed, 1 Dec 2021 16:16:16 +0300
Subject: [PATCH 09/25] Corrections

---
 .../src/codegen/derive_input_object.rs        |  2 +-
 .../juniper_tests/src/codegen/impl_scalar.rs  | 18 +++++----------
 .../juniper_tests/src/custom_scalar.rs        |  3 +--
 juniper/src/executor/mod.rs                   |  7 ++----
 .../src/executor_tests/introspection/mod.rs   |  3 +--
 juniper/src/integrations/chrono.rs            |  5 +++--
 juniper/src/macros/helper/mod.rs              |  6 ++---
 juniper/src/types/containers.rs               |  6 ++---
 juniper/src/types/scalars.rs                  | 15 +++++--------
 juniper/src/validation/test_harness.rs        | 12 +++++-----
 juniper_codegen/src/common/field/arg.rs       | 22 ++++++++++++-------
 juniper_codegen/src/common/field/mod.rs       |  4 ++--
 juniper_codegen/src/lib.rs                    |  4 ++--
 13 files changed, 49 insertions(+), 58 deletions(-)

diff --git a/integration_tests/juniper_tests/src/codegen/derive_input_object.rs b/integration_tests/juniper_tests/src/codegen/derive_input_object.rs
index fc9065fa1..f24f7bd59 100644
--- a/integration_tests/juniper_tests/src/codegen/derive_input_object.rs
+++ b/integration_tests/juniper_tests/src/codegen/derive_input_object.rs
@@ -61,7 +61,7 @@ impl<'a> FromInputValue for &'a Fake {
     type Error = FieldError;
 
     fn from_input_value(_v: &InputValue) -> Result<&'a Fake, Self::Error> {
-        Err(FieldError::from("This is fake"))
+        Err("This is fake".into())
     }
 }
 
diff --git a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
index 4c036b53d..facff5698 100644
--- a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
+++ b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
@@ -35,8 +35,7 @@ where
     fn from_input_value(v: &InputValue) -> Result<DefaultName, FieldError> {
         v.as_int_value()
             .map(DefaultName)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -53,8 +52,7 @@ impl GraphQLScalar for OtherOrder {
     fn from_input_value(v: &InputValue) -> Result<OtherOrder, FieldError> {
         v.as_int_value()
             .map(OtherOrder)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -71,8 +69,7 @@ impl GraphQLScalar for Named {
     fn from_input_value(v: &InputValue) -> Result<Named, FieldError> {
         v.as_int_value()
             .map(Named)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -89,8 +86,7 @@ impl GraphQLScalar for ScalarDescription {
     fn from_input_value(v: &InputValue) -> Result<ScalarDescription, FieldError> {
         v.as_int_value()
             .map(ScalarDescription)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -157,8 +153,7 @@ impl GraphQLScalar for WithCustomScalarValue {
     ) -> Result<WithCustomScalarValue, FieldError<MyScalarValue>> {
         v.as_int_value()
             .map(WithCustomScalarValue)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, MyScalarValue> {
@@ -217,8 +212,7 @@ fn path_in_resolve_return_type() {
         fn from_input_value(v: &InputValue) -> Result<ResolvePath, FieldError> {
             v.as_int_value()
                 .map(ResolvePath)
-                .ok_or_else(|| format!("Expected Int, found: {}", v))
-                .map_err(Into::into)
+                .ok_or_else(|| format!("Expected Int, found: {}", v).into())
         }
 
         fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
diff --git a/integration_tests/juniper_tests/src/custom_scalar.rs b/integration_tests/juniper_tests/src/custom_scalar.rs
index a2c12bbac..1ed488a6b 100644
--- a/integration_tests/juniper_tests/src/custom_scalar.rs
+++ b/integration_tests/juniper_tests/src/custom_scalar.rs
@@ -141,8 +141,7 @@ impl GraphQLScalar for i64 {
     fn from_input_value(v: &InputValue) -> Result<i64, FieldError> {
         v.as_scalar_value::<i64>()
             .copied()
-            .ok_or_else(|| format!("Expected MyScalarValue::Long(), found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected MyScalarValue::Long(), found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, MyScalarValue> {
diff --git a/juniper/src/executor/mod.rs b/juniper/src/executor/mod.rs
index 2bda95b2d..719ce7abc 100644
--- a/juniper/src/executor/mod.rs
+++ b/juniper/src/executor/mod.rs
@@ -151,11 +151,8 @@ where
 /// ```
 #[derive(Clone, Debug, PartialEq)]
 pub struct FieldError<S = DefaultScalarValue> {
-    /// Error message.
-    pub message: String,
-
-    /// [`Value`] containing additional information.
-    pub extensions: Value<S>,
+    message: String,
+    extensions: Value<S>,
 }
 
 impl<T: Display, S> From<T> for FieldError<S> {
diff --git a/juniper/src/executor_tests/introspection/mod.rs b/juniper/src/executor_tests/introspection/mod.rs
index b02d7c2f8..04be94de4 100644
--- a/juniper/src/executor_tests/introspection/mod.rs
+++ b/juniper/src/executor_tests/introspection/mod.rs
@@ -31,8 +31,7 @@ impl<S: ScalarValue> GraphQLScalar for Scalar {
     fn from_input_value(v: &InputValue) -> Result<Scalar, FieldError> {
         v.as_int_value()
             .map(Scalar)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/integrations/chrono.rs b/juniper/src/integrations/chrono.rs
index e20d1262c..82e28e42e 100644
--- a/juniper/src/integrations/chrono.rs
+++ b/juniper/src/integrations/chrono.rs
@@ -37,12 +37,13 @@ where
     }
 
     fn from_input_value(v: &InputValue) -> Result<DateTime<FixedOffset>, FieldError> {
-        Ok(v.as_string_value()
+        v.as_string_value()
             .ok_or_else(|| format!("Expected String, found: {}", v))
             .and_then(|s| {
                 DateTime::parse_from_rfc3339(s)
                     .map_err(|e| format!("Failed to parse DateTimeFixedOffset: {}", e))
-            })?)
+            })
+            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/macros/helper/mod.rs b/juniper/src/macros/helper/mod.rs
index 01caaf562..89249a7a9 100644
--- a/juniper/src/macros/helper/mod.rs
+++ b/juniper/src/macros/helper/mod.rs
@@ -33,12 +33,12 @@ pub trait AsDynGraphQLValue<S: ScalarValue = DefaultScalarValue> {
 
 crate::sa::assert_obj_safe!(AsDynGraphQLValue<Context = (), TypeInfo = ()>);
 
-/// This trait is used in `juniper::graphql_scalar` macro to [`Result`]s
-/// [`Error`].
+/// This trait is used in `juniper::graphql_scalar` macro to get [`Error`] type
+/// from a [`Result`].
 ///
 /// [`Error`]: Result::Error
 pub trait ExtractErrorFromResult {
-    /// [`Result`]s [`Error`].
+    /// [`Error`] of a [`Result`].
     ///
     /// [`Error`]: Result::Error
     type Error;
diff --git a/juniper/src/types/containers.rs b/juniper/src/types/containers.rs
index 053219a4d..14816194c 100644
--- a/juniper/src/types/containers.rs
+++ b/juniper/src/types/containers.rs
@@ -315,7 +315,7 @@ where
     /// Not enough elements.
     NotEnough(usize),
 
-    /// Too many elements. Value is [`Vec`] of __all__ [`InputValue`] elements.
+    /// Too many elements. Contains __all__ [`InputValue`] elements.
     TooMuch(Vec<T>),
 
     /// Underlying [`ScalarValue`] conversion error.
@@ -333,10 +333,10 @@ where
 
         match self {
             Self::NotEnough(len) => {
-                FieldError::<S>::from(format!("{}: required {} more elements", ERROR_PREFIX, len))
+                format!("{}: required {} more elements", ERROR_PREFIX, len).into()
             }
             Self::TooMuch(el) => {
-                FieldError::<S>::from(format!("{}: too much elements: {}", ERROR_PREFIX, el.len()))
+                format!("{}: too much elements: {}", ERROR_PREFIX, el.len()).into()
             }
             Self::Scalar(s) => s.into_field_error(),
         }
diff --git a/juniper/src/types/scalars.rs b/juniper/src/types/scalars.rs
index a5c6eee35..83039aba6 100644
--- a/juniper/src/types/scalars.rs
+++ b/juniper/src/types/scalars.rs
@@ -63,9 +63,8 @@ where
         v.as_string_value()
             .map(str::to_owned)
             .or_else(|| v.as_int_value().map(|i| i.to_string()))
-            .ok_or_else(|| format!("Expected String or Int, found: {}", v))
+            .ok_or_else(|| format!("Expected String or Int, found: {}", v).into())
             .map(ID)
-            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -88,8 +87,7 @@ where
     fn from_input_value(v: &InputValue) -> Result<String, FieldError> {
         v.as_string_value()
             .map(str::to_owned)
-            .ok_or_else(|| format!("Expected String, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected String, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -277,8 +275,7 @@ where
     fn from_input_value(v: &InputValue) -> Result<bool, FieldError> {
         v.as_scalar_value()
             .and_then(ScalarValue::as_boolean)
-            .ok_or_else(|| format!("Expected Boolean, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected Boolean, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -298,8 +295,7 @@ where
 
     fn from_input_value(v: &InputValue) -> Result<i32, FieldError> {
         v.as_int_value()
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -324,8 +320,7 @@ where
 
     fn from_input_value(v: &InputValue) -> Result<f64, FieldError> {
         v.as_float_value()
-            .ok_or_else(|| format!("Expected Float, found: {}", v))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected Float, found: {}", v).into())
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/validation/test_harness.rs b/juniper/src/validation/test_harness.rs
index e626a2ce5..0bff649c0 100644
--- a/juniper/src/validation/test_harness.rs
+++ b/juniper/src/validation/test_harness.rs
@@ -215,7 +215,7 @@ where
             Some("SIT") => Ok(DogCommand::Sit),
             Some("HEEL") => Ok(DogCommand::Heel),
             Some("DOWN") => Ok(DogCommand::Down),
-            _ => Err("Unknown command".into()),
+            _ => Err("Unknown DogCommand".into()),
         }
     }
 }
@@ -324,7 +324,7 @@ where
             Some("BLACK") => Ok(FurColor::Black),
             Some("TAN") => Ok(FurColor::Tan),
             Some("SPOTTED") => Ok(FurColor::Spotted),
-            _ => Err("Unknown color".into()),
+            _ => Err("Unknown FurColor".into()),
         }
     }
 }
@@ -631,22 +631,22 @@ where
                 .get("intField")
                 .map(|v| v.convert().map_err(FieldError::map_scalar_value))
                 .transpose()?
-                .ok_or("Expected requiredField")?,
+                .ok_or("Expected intField")?,
             string_field: obj
                 .get("stringField")
                 .map(|v| v.convert().map_err(FieldError::map_scalar_value))
                 .transpose()?
-                .ok_or("Expected requiredField")?,
+                .ok_or("Expected stringField")?,
             boolean_field: obj
                 .get("booleanField")
                 .map(|v| v.convert().map_err(FieldError::map_scalar_value))
                 .transpose()?
-                .ok_or("Expected requiredField")?,
+                .ok_or("Expected booleanField")?,
             string_list_field: obj
                 .get("stringListField")
                 .map(|v| v.convert().map_err(FieldError::map_scalar_value))
                 .transpose()?
-                .ok_or("Expected requiredField")?,
+                .ok_or("Expected stringListField")?,
         })
     }
 }
diff --git a/juniper_codegen/src/common/field/arg.rs b/juniper_codegen/src/common/field/arg.rs
index 56e01afca..274f93532 100644
--- a/juniper_codegen/src/common/field/arg.rs
+++ b/juniper_codegen/src/common/field/arg.rs
@@ -357,11 +357,14 @@ impl OnMethod {
                         .and_then(|opt| {
                             opt.map_or_else(
                                 || {
-                                    <#ty as ::juniper::FromInputValue<#scalar>>::from_implicit_null()
+                                    <#ty as ::juniper::FromInputValue<#scalar>>::
+                                        from_implicit_null()
                                         .map_err(|e| {
-                                            let mut e = ::juniper::IntoFieldError::into_field_error(e);
-                                            e.message = format!(#err_text, e.message);
-                                            e
+                                            let e = ::juniper::IntoFieldError::into_field_error(e);
+                                            ::juniper::FieldError::new(
+                                                format!(#err_text, e.message()),
+                                                e.extensions().clone(),
+                                            )
                                         })
                                 },
                                 Ok,
@@ -394,11 +397,14 @@ impl OnMethod {
                         .and_then(|opt| {
                             opt.map_or_else(
                                 || {
-                                    <#ty as ::juniper::FromInputValue<#scalar>>::from_implicit_null()
+                                    <#ty as ::juniper::FromInputValue<#scalar>>::
+                                        from_implicit_null()
                                         .map_err(|e| {
-                                            let mut e = ::juniper::IntoFieldError::into_field_error(e);
-                                            e.message = format!(#err_text, e.message);
-                                            e
+                                            let e = ::juniper::IntoFieldError::into_field_error(e);
+                                            ::juniper::FieldError::new(
+                                                format!(#err_text, e.message()),
+                                                e.extensions().clone(),
+                                            )
                                         })
                                 },
                                 Ok,
diff --git a/juniper_codegen/src/common/field/mod.rs b/juniper_codegen/src/common/field/mod.rs
index 360cb28bb..fbf442ced 100644
--- a/juniper_codegen/src/common/field/mod.rs
+++ b/juniper_codegen/src/common/field/mod.rs
@@ -268,7 +268,7 @@ impl Definition {
         self.arguments.is_some()
     }
 
-    /// Returns generated code that panics about unknown [GraphQL field][1]
+    /// Returns generated code that errors about unknown [GraphQL field][1]
     /// tried to be resolved in the [`GraphQLValue::resolve_field`] method.
     ///
     /// [`GraphQLValue::resolve_field`]: juniper::GraphQLValue::resolve_field
@@ -285,7 +285,7 @@ impl Definition {
         }
     }
 
-    /// Returns generated code that panics about [GraphQL fields][1] tried to be
+    /// Returns generated code that errors about [GraphQL fields][1] tried to be
     /// resolved asynchronously in the [`GraphQLValue::resolve_field`] method
     /// (which is synchronous itself).
     ///
diff --git a/juniper_codegen/src/lib.rs b/juniper_codegen/src/lib.rs
index a7bdf882e..b18b84702 100644
--- a/juniper_codegen/src/lib.rs
+++ b/juniper_codegen/src/lib.rs
@@ -231,9 +231,9 @@ pub fn derive_scalar_value(input: TokenStream) -> TokenStream {
 ///     }
 ///
 ///     fn from_input_value(value: &juniper::InputValue) -> Result<UserID, juniper::FieldError> {
-///         Ok(value.as_string_value()
+///         value.as_string_value()
 ///             .map(|s| UserID(s.to_owned()))
-///             .ok_or_else(|| format!("Expected String, found: {}", value))?)
+///             .ok_or_else(|| format!("Expected String, found: {}", value).into())
 ///     }
 ///
 ///     fn from_str<'a>(value: juniper::ScalarToken<'a>) -> juniper::ParseScalarResult<'a, S> {

From 115c55ff5a73805bf8a7d18da753a07f35560890 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Wed, 1 Dec 2021 16:22:35 +0300
Subject: [PATCH 10/25] CHANGELOG

---
 juniper/CHANGELOG.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/juniper/CHANGELOG.md b/juniper/CHANGELOG.md
index 5c968de4b..720a3b490 100644
--- a/juniper/CHANGELOG.md
+++ b/juniper/CHANGELOG.md
@@ -7,6 +7,8 @@
 - `#[graphql_object]` and `#[graphql_subscription]` macros expansion now preserves defined `impl` blocks "as is" and reuses defined methods in opaque way. ([#971](https://github.com/graphql-rust/juniper/pull/971))
 - `rename = "<policy>"` attribute's argument renamed to `rename_all = "<policy>"`. ([#971](https://github.com/graphql-rust/juniper/pull/971))
 - Upgrade `bson` feature to [2.0 version of its crate](https://github.com/mongodb/bson-rust/releases/tag/v2.0.0). ([#979](https://github.com/graphql-rust/juniper/pull/979))
+- Make `FromInputValue` methods fallible to allow post-validation. ([#987](https://github.com/graphql-rust/juniper/pull/987))
+- Change `Option` to `Result` in `#[graphql_scalar]` macro in `from_input_value()` return type. ([#987](https://github.com/graphql-rust/juniper/pull/987))
 
 ## Features
 

From 06e71c3bf69c859b78602fb7e644b22ecac80a8d Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Wed, 1 Dec 2021 16:41:36 +0300
Subject: [PATCH 11/25] Correction

---
 juniper/src/integrations/chrono_tz.rs | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/juniper/src/integrations/chrono_tz.rs b/juniper/src/integrations/chrono_tz.rs
index c7f383a01..aa7b9020a 100644
--- a/juniper/src/integrations/chrono_tz.rs
+++ b/juniper/src/integrations/chrono_tz.rs
@@ -43,16 +43,20 @@ where
 #[cfg(test)]
 mod test {
     mod from_input_value {
+        use std::ops::Deref;
+
         use chrono_tz::Tz;
 
         use crate::{graphql_input_value, FieldError, FromInputValue, InputValue};
 
         fn tz_input_test(raw: &'static str, expected: Result<Tz, &str>) {
             let input: InputValue = graphql_input_value!((raw));
-            let parsed =
-                FromInputValue::from_input_value(&input).map_err(|e: FieldError| e.message);
+            let parsed = FromInputValue::from_input_value(&input);
 
-            assert_eq!(parsed, expected.map_err(str::to_owned));
+            assert_eq!(
+                parsed.as_ref().map_err(|e: &FieldError| e.message()),
+                expected.as_ref().map_err(Deref::deref),
+            );
         }
 
         #[test]

From 53a7c69d25a350a1a033d0aaecaf5d1608e46535 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Wed, 8 Dec 2021 15:19:09 +0300
Subject: [PATCH 12/25] Forbid `__typename` on subscription root

---
 .../juniper_tests/src/issue_372.rs            | 52 +++++++++++++------
 juniper/src/types/subscriptions.rs            | 11 ----
 .../rules/fields_on_correct_type.rs           | 22 ++++++++
 3 files changed, 59 insertions(+), 26 deletions(-)

diff --git a/integration_tests/juniper_tests/src/issue_372.rs b/integration_tests/juniper_tests/src/issue_372.rs
index 8d765176a..70472df6f 100644
--- a/integration_tests/juniper_tests/src/issue_372.rs
+++ b/integration_tests/juniper_tests/src/issue_372.rs
@@ -1,14 +1,12 @@
 //! Checks that `__typename` field queries okay on root types.
 //! See [#372](https://github.com/graphql-rust/juniper/issues/372) for details.
 
-use futures::{stream, FutureExt as _};
+use futures::stream;
 use juniper::{
     execute, graphql_object, graphql_subscription, graphql_value, graphql_vars,
     resolve_into_stream, RootNode,
 };
 
-use crate::util::extract_next;
-
 pub struct Query;
 
 #[graphql_object]
@@ -98,28 +96,52 @@ async fn explicit_mutation_typename() {
 
 #[tokio::test]
 async fn subscription_typename() {
+    use juniper::GraphQLError;
+
     let query = r#"subscription { __typename }"#;
 
     let schema = RootNode::new(Query, Mutation, Subscription);
 
-    assert_eq!(
-        resolve_into_stream(query, None, &schema, &graphql_vars! {}, &())
-            .then(|s| extract_next(s))
-            .await,
-        Ok((graphql_value!({"__typename": "Subscription"}), vec![])),
-    );
+    match resolve_into_stream(query, None, &schema, &graphql_vars! {}, &()).await {
+        Err(GraphQLError::ValidationError(mut errors)) => {
+            assert_eq!(errors.len(), 1);
+
+            let error = errors.pop().unwrap();
+            assert_eq!(
+                error.message(),
+                "__typename may not be included as a root field in a \
+                 subscription operation"
+            );
+            assert_eq!(error.locations()[0].index(), 15);
+            assert_eq!(error.locations()[0].line(), 0);
+            assert_eq!(error.locations()[0].column(), 15);
+        }
+        _ => panic!("Expected ValidationError"),
+    };
 }
 
 #[tokio::test]
 async fn explicit_subscription_typename() {
+    use juniper::GraphQLError;
+
     let query = r#"subscription Subscription { __typename }"#;
 
     let schema = RootNode::new(Query, Mutation, Subscription);
 
-    assert_eq!(
-        resolve_into_stream(query, None, &schema, &graphql_vars! {}, &())
-            .then(|s| extract_next(s))
-            .await,
-        Ok((graphql_value!({"__typename": "Subscription"}), vec![])),
-    );
+    match resolve_into_stream(query, None, &schema, &graphql_vars! {}, &()).await {
+        Err(GraphQLError::ValidationError(mut errors)) => {
+            assert_eq!(errors.len(), 1);
+
+            let error = errors.pop().unwrap();
+            assert_eq!(
+                error.message(),
+                "__typename may not be included as a root field in a \
+                 subscription operation"
+            );
+            assert_eq!(error.locations()[0].index(), 28);
+            assert_eq!(error.locations()[0].line(), 0);
+            assert_eq!(error.locations()[0].column(), 28);
+        }
+        _ => panic!("Expected ValidationError"),
+    };
 }
diff --git a/juniper/src/types/subscriptions.rs b/juniper/src/types/subscriptions.rs
index c8ac53af3..e99a5aafa 100644
--- a/juniper/src/types/subscriptions.rs
+++ b/juniper/src/types/subscriptions.rs
@@ -1,4 +1,3 @@
-use futures::{future, stream};
 use serde::Serialize;
 
 use crate::{
@@ -293,16 +292,6 @@ where
 
                 let response_name = f.alias.as_ref().unwrap_or(&f.name).item;
 
-                if f.name.item == "__typename" {
-                    let typename =
-                        Value::scalar(instance.concrete_type_name(executor.context(), info));
-                    object.add_field(
-                        response_name,
-                        Value::Scalar(Box::pin(stream::once(future::ok(typename)))),
-                    );
-                    continue;
-                }
-
                 let meta_field = meta_type
                     .field_by_name(f.name.item)
                     .unwrap_or_else(|| {
diff --git a/juniper/src/validation/rules/fields_on_correct_type.rs b/juniper/src/validation/rules/fields_on_correct_type.rs
index c15379aac..8017a06f4 100644
--- a/juniper/src/validation/rules/fields_on_correct_type.rs
+++ b/juniper/src/validation/rules/fields_on_correct_type.rs
@@ -4,6 +4,7 @@ use crate::{
     schema::meta::MetaType,
     validation::{ValidatorContext, Visitor},
     value::ScalarValue,
+    Operation, OperationType, Selection,
 };
 
 pub struct FieldsOnCorrectType;
@@ -16,6 +17,27 @@ impl<'a, S> Visitor<'a, S> for FieldsOnCorrectType
 where
     S: ScalarValue,
 {
+    fn enter_operation_definition(
+        &mut self,
+        context: &mut ValidatorContext<'a, S>,
+        operation: &'a Spanning<Operation<S>>,
+    ) {
+        // https://spec.graphql.org/October2021/#note-bc213
+        if let OperationType::Subscription = operation.item.operation_type {
+            for selection in &operation.item.selection_set {
+                if let Selection::Field(field) = selection {
+                    if field.item.name.item == "__typename" {
+                        context.report_error(
+                            "__typename may not be included as a root \
+                            field in a subscription operation",
+                            &[field.item.name.start],
+                        );
+                    }
+                }
+            }
+        }
+    }
+
     fn enter_field(
         &mut self,
         context: &mut ValidatorContext<'a, S>,

From c1d563164e1bb8448f83a4c010a916c2240bcf3f Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Thu, 9 Dec 2021 15:24:25 +0300
Subject: [PATCH 13/25] CHANGELOG

---
 juniper/CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/juniper/CHANGELOG.md b/juniper/CHANGELOG.md
index 5c968de4b..118f46f7e 100644
--- a/juniper/CHANGELOG.md
+++ b/juniper/CHANGELOG.md
@@ -7,6 +7,7 @@
 - `#[graphql_object]` and `#[graphql_subscription]` macros expansion now preserves defined `impl` blocks "as is" and reuses defined methods in opaque way. ([#971](https://github.com/graphql-rust/juniper/pull/971))
 - `rename = "<policy>"` attribute's argument renamed to `rename_all = "<policy>"`. ([#971](https://github.com/graphql-rust/juniper/pull/971))
 - Upgrade `bson` feature to [2.0 version of its crate](https://github.com/mongodb/bson-rust/releases/tag/v2.0.0). ([#979](https://github.com/graphql-rust/juniper/pull/979))
+- Forbid `__typename` field query on `subscription` [accordingly to the October 2021 spec](https://spec.graphql.org/October2021/#note-bc213). ([#1001](https://github.com/graphql-rust/juniper/pull/1001), [#1000](https://github.com/graphql-rust/juniper/pull/1000))
 
 ## Features
 

From 64f7f8ea852e3e8ef59802358921029b96abb559 Mon Sep 17 00:00:00 2001
From: tyranron <tyranron@gmail.com>
Date: Thu, 9 Dec 2021 15:23:22 +0100
Subject: [PATCH 14/25] Minor corrections

---
 integration_tests/juniper_tests/src/issue_372.rs   | 14 +++++---------
 juniper/CHANGELOG.md                               |  2 +-
 .../src/validation/rules/fields_on_correct_type.rs |  4 ++--
 3 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/integration_tests/juniper_tests/src/issue_372.rs b/integration_tests/juniper_tests/src/issue_372.rs
index 70472df6f..c92ef6aa3 100644
--- a/integration_tests/juniper_tests/src/issue_372.rs
+++ b/integration_tests/juniper_tests/src/issue_372.rs
@@ -1,10 +1,10 @@
-//! Checks that `__typename` field queries okay on root types.
+//! Checks that `__typename` field queries okay (and not okay) on root types.
 //! See [#372](https://github.com/graphql-rust/juniper/issues/372) for details.
 
 use futures::stream;
 use juniper::{
     execute, graphql_object, graphql_subscription, graphql_value, graphql_vars,
-    resolve_into_stream, RootNode,
+    resolve_into_stream, GraphQLError, RootNode,
 };
 
 pub struct Query;
@@ -96,8 +96,6 @@ async fn explicit_mutation_typename() {
 
 #[tokio::test]
 async fn subscription_typename() {
-    use juniper::GraphQLError;
-
     let query = r#"subscription { __typename }"#;
 
     let schema = RootNode::new(Query, Mutation, Subscription);
@@ -109,8 +107,8 @@ async fn subscription_typename() {
             let error = errors.pop().unwrap();
             assert_eq!(
                 error.message(),
-                "__typename may not be included as a root field in a \
-                 subscription operation"
+                "`__typename` may not be included as a root field in a \
+                 subscription operation",
             );
             assert_eq!(error.locations()[0].index(), 15);
             assert_eq!(error.locations()[0].line(), 0);
@@ -122,8 +120,6 @@ async fn subscription_typename() {
 
 #[tokio::test]
 async fn explicit_subscription_typename() {
-    use juniper::GraphQLError;
-
     let query = r#"subscription Subscription { __typename }"#;
 
     let schema = RootNode::new(Query, Mutation, Subscription);
@@ -135,7 +131,7 @@ async fn explicit_subscription_typename() {
             let error = errors.pop().unwrap();
             assert_eq!(
                 error.message(),
-                "__typename may not be included as a root field in a \
+                "`__typename` may not be included as a root field in a \
                  subscription operation"
             );
             assert_eq!(error.locations()[0].index(), 28);
diff --git a/juniper/CHANGELOG.md b/juniper/CHANGELOG.md
index 118f46f7e..f773885ba 100644
--- a/juniper/CHANGELOG.md
+++ b/juniper/CHANGELOG.md
@@ -7,7 +7,7 @@
 - `#[graphql_object]` and `#[graphql_subscription]` macros expansion now preserves defined `impl` blocks "as is" and reuses defined methods in opaque way. ([#971](https://github.com/graphql-rust/juniper/pull/971))
 - `rename = "<policy>"` attribute's argument renamed to `rename_all = "<policy>"`. ([#971](https://github.com/graphql-rust/juniper/pull/971))
 - Upgrade `bson` feature to [2.0 version of its crate](https://github.com/mongodb/bson-rust/releases/tag/v2.0.0). ([#979](https://github.com/graphql-rust/juniper/pull/979))
-- Forbid `__typename` field query on `subscription` [accordingly to the October 2021 spec](https://spec.graphql.org/October2021/#note-bc213). ([#1001](https://github.com/graphql-rust/juniper/pull/1001), [#1000](https://github.com/graphql-rust/juniper/pull/1000))
+- Forbid `__typename` field query on `subscription` operations [accordingly to October 2021 spec](https://spec.graphql.org/October2021/#note-bc213). ([#1001](https://github.com/graphql-rust/juniper/pull/1001), [#1000](https://github.com/graphql-rust/juniper/pull/1000))
 
 ## Features
 
diff --git a/juniper/src/validation/rules/fields_on_correct_type.rs b/juniper/src/validation/rules/fields_on_correct_type.rs
index 8017a06f4..68e6cc281 100644
--- a/juniper/src/validation/rules/fields_on_correct_type.rs
+++ b/juniper/src/validation/rules/fields_on_correct_type.rs
@@ -28,8 +28,8 @@ where
                 if let Selection::Field(field) = selection {
                     if field.item.name.item == "__typename" {
                         context.report_error(
-                            "__typename may not be included as a root \
-                            field in a subscription operation",
+                            "`__typename` may not be included as a root \
+                             field in a subscription operation",
                             &[field.item.name.start],
                         );
                     }

From 5cc75552feec4474c8c304142e65cc11f17a3471 Mon Sep 17 00:00:00 2001
From: tyranron <tyranron@gmail.com>
Date: Fri, 10 Dec 2021 18:29:03 +0100
Subject: [PATCH 15/25] Corrections

---
 juniper/src/ast.rs                            |   9 +-
 juniper/src/executor/mod.rs                   |  30 +++-
 .../introspection/input_object.rs             |   2 +-
 .../src/executor_tests/introspection/mod.rs   |   8 +-
 juniper/src/executor_tests/variables.rs       |   5 +-
 juniper/src/integrations/bson.rs              |  16 +-
 juniper/src/integrations/chrono.rs            |  35 ++--
 juniper/src/integrations/chrono_tz.rs         |  15 +-
 juniper/src/integrations/url.rs               |   9 +-
 juniper/src/integrations/uuid.rs              |   9 +-
 juniper/src/lib.rs                            |   2 +-
 juniper/src/macros/helper/mod.rs              |   9 +-
 juniper/src/schema/meta.rs                    |  22 ++-
 juniper/src/types/containers.rs               | 155 ++++++++++--------
 juniper/src/types/scalars.rs                  |  22 +--
 juniper/src/types/utilities.rs                |   2 +-
 juniper/src/validation/input_value.rs         |  19 ++-
 juniper/src/validation/test_harness.rs        |  22 +--
 juniper_codegen/src/graphql_union/mod.rs      |   4 +-
 juniper_codegen/src/impl_scalar.rs            |   2 +-
 juniper_codegen/src/lib.rs                    |   5 +-
 juniper_codegen/src/util/mod.rs               |  17 +-
 22 files changed, 232 insertions(+), 187 deletions(-)

diff --git a/juniper/src/ast.rs b/juniper/src/ast.rs
index 3c5971d26..a3f1d8034 100644
--- a/juniper/src/ast.rs
+++ b/juniper/src/ast.rs
@@ -150,7 +150,7 @@ pub type Document<'a, S> = [Definition<'a, S>];
 #[doc(hidden)]
 pub type OwnedDocument<'a, S> = Vec<Definition<'a, S>>;
 
-/// Parse an unstructured input value into a Rust data type.
+/// Parsing of an unstructured input value into a Rust data type.
 ///
 /// The conversion _can_ fail, and must in that case return [`Err`]. Thus not
 /// restricted in the definition of this trait, the returned [`Err`] should be
@@ -178,9 +178,10 @@ pub trait FromInputValue<S = DefaultScalarValue>: Sized {
     /// Performs the conversion from an absent value (e.g. to distinguish
     /// between implicit and explicit `null`).
     ///
-    /// The default implementation just calls
-    /// [`FromInputValue::from_input_value()`] as if an explicit `null` was
-    /// provided.
+    /// The default implementation just calls [`from_input_value()`] as if an
+    /// explicit `null` was provided.
+    ///
+    /// [`from_input_value()`]: FromInputValue::from_input_value
     fn from_implicit_null() -> Result<Self, Self::Error> {
         Self::from_input_value(&InputValue::<S>::Null)
     }
diff --git a/juniper/src/executor/mod.rs b/juniper/src/executor/mod.rs
index 719ce7abc..5a8cf32c7 100644
--- a/juniper/src/executor/mod.rs
+++ b/juniper/src/executor/mod.rs
@@ -167,12 +167,11 @@ impl<T: Display, S> From<T> for FieldError<S> {
 impl<S> FieldError<S> {
     /// Construct a new [`FieldError`] with additional data.
     ///
-    /// You can use the [`graphql_value!`] macro to construct an error:
+    /// You can use the [`graphql_value!`] macro for construction:
     /// ```rust
-    /// # use juniper::DefaultScalarValue;
     /// use juniper::{graphql_value, FieldError};
     ///
-    /// # let _: FieldError<DefaultScalarValue> =
+    /// # let _: FieldError =
     /// FieldError::new(
     ///     "Could not open connection to the database",
     ///     graphql_value!({"internal_error": "Connection refused"}),
@@ -212,7 +211,7 @@ impl<S> FieldError<S> {
 
     /// Returns `"extensions"` field of this [`FieldError`].
     ///
-    /// If there is none `"extensions"` then [`Value::Null`] will be returned.
+    /// If there is no `"extensions"`, then [`Value::Null`] will be returned.
     #[must_use]
     pub fn extensions(&self) -> &Value<S> {
         &self.extensions
@@ -249,7 +248,7 @@ pub type Variables<S = DefaultScalarValue> = HashMap<String, InputValue<S>>;
 /// Custom error handling trait to enable error types other than [`FieldError`]
 /// to be specified as return value.
 ///
-/// Any custom error type should implement this trait to convert itself to a
+/// Any custom error type should implement this trait to convert itself into a
 /// [`FieldError`].
 pub trait IntoFieldError<S = DefaultScalarValue> {
     /// Performs the custom conversion into a [`FieldError`].
@@ -269,6 +268,24 @@ impl<S> IntoFieldError<S> for std::convert::Infallible {
     }
 }
 
+impl<'a, S> IntoFieldError<S> for &'a str {
+    fn into_field_error(self) -> FieldError<S> {
+        FieldError::<S>::from(self)
+    }
+}
+
+impl<S> IntoFieldError<S> for String {
+    fn into_field_error(self) -> FieldError<S> {
+        FieldError::<S>::from(self)
+    }
+}
+
+impl<'a, S> IntoFieldError<S> for Cow<'a, str> {
+    fn into_field_error(self) -> FieldError<S> {
+        FieldError::<S>::from(self)
+    }
+}
+
 #[doc(hidden)]
 pub trait IntoResolvable<'a, S, T, C>
 where
@@ -1228,6 +1245,7 @@ impl<'r, S: 'r> Registry<'r, S> {
     pub fn build_scalar_type<T>(&mut self, info: &T::TypeInfo) -> ScalarMeta<'r, S>
     where
         T: GraphQLType<S> + FromInputValue<S> + ParseScalarValue<S> + 'r,
+        T::Error: IntoFieldError<S>,
         S: ScalarValue,
     {
         let name = T::name(info).expect("Scalar types must be named. Implement `name()`");
@@ -1287,6 +1305,7 @@ impl<'r, S: 'r> Registry<'r, S> {
     ) -> EnumMeta<'r, S>
     where
         T: GraphQLType<S> + FromInputValue<S>,
+        T::Error: IntoFieldError<S>,
         S: ScalarValue,
     {
         let name = T::name(info).expect("Enum types must be named. Implement `name()`");
@@ -1330,6 +1349,7 @@ impl<'r, S: 'r> Registry<'r, S> {
     ) -> InputObjectMeta<'r, S>
     where
         T: GraphQLType<S> + FromInputValue<S>,
+        T::Error: IntoFieldError<S>,
         S: ScalarValue,
     {
         let name = T::name(info).expect("Input object types must be named. Implement name()");
diff --git a/juniper/src/executor_tests/introspection/input_object.rs b/juniper/src/executor_tests/introspection/input_object.rs
index d433681a5..b3451463c 100644
--- a/juniper/src/executor_tests/introspection/input_object.rs
+++ b/juniper/src/executor_tests/introspection/input_object.rs
@@ -206,7 +206,7 @@ fn default_name_input_value() {
 
     let dv = DefaultName::from_input_value(&iv);
 
-    assert!(dv.is_ok(), "error: {:?}", dv.unwrap_err());
+    assert!(dv.is_ok(), "error: {}", dv.unwrap_err());
 
     let dv = dv.unwrap();
 
diff --git a/juniper/src/executor_tests/introspection/mod.rs b/juniper/src/executor_tests/introspection/mod.rs
index 04be94de4..c26baf1eb 100644
--- a/juniper/src/executor_tests/introspection/mod.rs
+++ b/juniper/src/executor_tests/introspection/mod.rs
@@ -9,8 +9,8 @@ use crate::{
     graphql_interface, graphql_object, graphql_scalar, graphql_value, graphql_vars,
     schema::model::RootNode,
     types::scalars::{EmptyMutation, EmptySubscription},
-    value::{ParseScalarResult, ParseScalarValue, Value},
-    FieldError, GraphQLEnum,
+    value::{ParseScalarResult, ParseScalarValue, ScalarValue, Value},
+    GraphQLEnum,
 };
 
 #[derive(GraphQLEnum)]
@@ -28,10 +28,10 @@ impl<S: ScalarValue> GraphQLScalar for Scalar {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<Scalar, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<Scalar, String> {
         v.as_int_value()
             .map(Scalar)
-            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
+            .ok_or_else(|| format!("Expected `Int`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/executor_tests/variables.rs b/juniper/src/executor_tests/variables.rs
index be895dc95..f2e3bb818 100644
--- a/juniper/src/executor_tests/variables.rs
+++ b/juniper/src/executor_tests/variables.rs
@@ -6,7 +6,6 @@ use crate::{
     types::scalars::{EmptyMutation, EmptySubscription},
     validation::RuleError,
     value::{DefaultScalarValue, Object, ParseScalarResult, ParseScalarValue},
-    FieldError,
     GraphQLError::ValidationError,
     GraphQLInputObject,
 };
@@ -20,11 +19,11 @@ impl<S: ScalarValue> GraphQLScalar for TestComplexScalar {
         graphql_value!("SerializedValue")
     }
 
-    fn from_input_value(v: &InputValue) -> Result<TestComplexScalar, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<TestComplexScalar, String> {
         v.as_string_value()
             .filter(|s| *s == "SerializedValue")
             .map(|_| TestComplexScalar)
-            .ok_or_else(|| format!("Expected SerializedValue String, found: {}", v).into())
+            .ok_or_else(|| format!("Expected SerializedValue String, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/integrations/bson.rs b/juniper/src/integrations/bson.rs
index ee502c1f7..e1c9c1cf5 100644
--- a/juniper/src/integrations/bson.rs
+++ b/juniper/src/integrations/bson.rs
@@ -7,7 +7,7 @@ use crate::{
     graphql_scalar,
     parser::{ParseError, ScalarToken, Token},
     value::ParseScalarResult,
-    FieldError, Value,
+    Value,
 };
 
 #[graphql_scalar(description = "ObjectId")]
@@ -19,13 +19,12 @@ where
         Value::scalar(self.to_hex())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<ObjectId, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<ObjectId, String> {
         v.as_string_value()
-            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
             .and_then(|s| {
-                Self::parse_str(s).map_err(|e| format!("Failed to parse UtcDateTime: {}", e))
+                Self::parse_str(s).map_err(|e| format!("Failed to parse `ObjectId`: {}", e))
             })
-            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -46,15 +45,14 @@ where
         Value::scalar((*self).to_chrono().to_rfc3339())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<UtcDateTime, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<UtcDateTime, String> {
         v.as_string_value()
-            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
             .and_then(|s| {
                 s.parse::<DateTime<Utc>>()
-                    .map_err(|e| format!("Failed to parse UtcDateTime: {}", e))
+                    .map_err(|e| format!("Failed to parse `UtcDateTime`: {}", e))
             })
             .map(Self::from_chrono)
-            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/integrations/chrono.rs b/juniper/src/integrations/chrono.rs
index 82e28e42e..9c0c5f64a 100644
--- a/juniper/src/integrations/chrono.rs
+++ b/juniper/src/integrations/chrono.rs
@@ -21,7 +21,7 @@ use chrono::prelude::*;
 use crate::{
     parser::{ParseError, ScalarToken, Token},
     value::{ParseScalarResult, ParseScalarValue},
-    FieldError, Value,
+    Value,
 };
 
 #[doc(hidden)]
@@ -36,14 +36,13 @@ where
         Value::scalar(self.to_rfc3339())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<DateTime<FixedOffset>, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<DateTime<FixedOffset>, String> {
         v.as_string_value()
-            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
             .and_then(|s| {
                 DateTime::parse_from_rfc3339(s)
-                    .map_err(|e| format!("Failed to parse DateTimeFixedOffset: {}", e))
+                    .map_err(|e| format!("Failed to parse `DateTimeFixedOffset`: {}", e))
             })
-            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -64,14 +63,13 @@ where
         Value::scalar(self.to_rfc3339())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<DateTime<Utc>, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<DateTime<Utc>, String> {
         v.as_string_value()
-            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
             .and_then(|s| {
                 s.parse::<DateTime<Utc>>()
-                    .map_err(|e| format!("Failed to parse DateTime: {}", e))
+                    .map_err(|e| format!("Failed to parse `DateTimeUtc`: {}", e))
             })
-            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -97,14 +95,13 @@ where
         Value::scalar(self.format("%Y-%m-%d").to_string())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<NaiveDate, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<NaiveDate, String> {
         v.as_string_value()
-            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
             .and_then(|s| {
                 NaiveDate::parse_from_str(s, "%Y-%m-%d")
-                    .map_err(|e| format!("Failed to parse NaiveDate: {}", e))
+                    .map_err(|e| format!("Failed to parse `NaiveDate`: {}", e))
             })
-            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -126,14 +123,13 @@ where
         Value::scalar(self.format("%H:%M:%S").to_string())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<NaiveTime, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<NaiveTime, String> {
         v.as_string_value()
-            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
             .and_then(|s| {
                 NaiveTime::parse_from_str(s, "%H:%M:%S")
-                    .map_err(|e| format!("Failed to parse NaiveTime: {}", e))
+                    .map_err(|e| format!("Failed to parse `NaiveTime`: {}", e))
             })
-            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -156,15 +152,14 @@ where
         Value::scalar(self.timestamp() as f64)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<NaiveDateTime, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<NaiveDateTime, String> {
         v.as_float_value()
-            .ok_or_else(|| format!("Expected Float, found: {}", v))
+            .ok_or_else(|| format!("Expected `Float`, found: {}", v))
             .and_then(|f| {
                 let secs = f as i64;
                 NaiveDateTime::from_timestamp_opt(secs, 0)
                     .ok_or_else(|| format!("Out-of-range number of seconds: {}", secs))
             })
-            .map_err(Into::into)
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/integrations/chrono_tz.rs b/juniper/src/integrations/chrono_tz.rs
index aa7b9020a..9947015fd 100644
--- a/juniper/src/integrations/chrono_tz.rs
+++ b/juniper/src/integrations/chrono_tz.rs
@@ -9,7 +9,7 @@ use crate::{
     graphql_scalar,
     parser::{ParseError, ScalarToken, Token},
     value::ParseScalarResult,
-    FieldError, Value,
+    Value,
 };
 
 #[graphql_scalar(name = "Tz", description = "Timezone")]
@@ -21,14 +21,13 @@ where
         Value::scalar(self.name().to_owned())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<Tz, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<Tz, String> {
         v.as_string_value()
-            .ok_or_else(|| format!("Expected String, found: {}", v))
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
             .and_then(|s| {
                 s.parse::<Tz>()
-                    .map_err(|e| format!("Failed to parse Timezone: {}", e))
+                    .map_err(|e| format!("Failed to parse `Tz`: {}", e))
             })
-            .map_err(Into::into)
     }
 
     fn from_str<'a>(val: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -76,7 +75,7 @@ mod test {
             fn forward_slash() {
                 tz_input_test(
                     "Abc/Xyz",
-                    Err("Failed to parse Timezone: received invalid timezone"),
+                    Err("Failed to parse `Timezone`: received invalid timezone"),
                 );
             }
 
@@ -84,7 +83,7 @@ mod test {
             fn number() {
                 tz_input_test(
                     "8086",
-                    Err("Failed to parse Timezone: received invalid timezone"),
+                    Err("Failed to parse `Timezone`: received invalid timezone"),
                 );
             }
 
@@ -92,7 +91,7 @@ mod test {
             fn no_forward_slash() {
                 tz_input_test(
                     "AbcXyz",
-                    Err("Failed to parse Timezone: received invalid timezone"),
+                    Err("Failed to parse `Timezone`: received invalid timezone"),
                 );
             }
         }
diff --git a/juniper/src/integrations/url.rs b/juniper/src/integrations/url.rs
index b3ae25196..97481bb20 100644
--- a/juniper/src/integrations/url.rs
+++ b/juniper/src/integrations/url.rs
@@ -4,7 +4,7 @@ use url::Url;
 
 use crate::{
     value::{ParseScalarResult, ParseScalarValue},
-    FieldError, Value,
+    Value,
 };
 
 #[crate::graphql_scalar(description = "Url")]
@@ -16,11 +16,10 @@ where
         Value::scalar(self.as_str().to_owned())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<Url, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<Url, String> {
         v.as_string_value()
-            .ok_or_else(|| format!("Expected String, found: {}", v))
-            .and_then(|s| Url::parse(s).map_err(|e| format!("Failed to parse Url: {}", e)))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
+            .and_then(|s| Url::parse(s).map_err(|e| format!("Failed to parse `Url`: {}", e)))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/integrations/uuid.rs b/juniper/src/integrations/uuid.rs
index 5dfa7a7bb..ae0c04a87 100644
--- a/juniper/src/integrations/uuid.rs
+++ b/juniper/src/integrations/uuid.rs
@@ -7,7 +7,7 @@ use uuid::Uuid;
 use crate::{
     parser::{ParseError, ScalarToken, Token},
     value::ParseScalarResult,
-    FieldError, Value,
+    Value,
 };
 
 #[crate::graphql_scalar(description = "Uuid")]
@@ -19,11 +19,10 @@ where
         Value::scalar(self.to_string())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<Uuid, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<Uuid, String> {
         v.as_string_value()
-            .ok_or_else(|| format!("Expected String, found: {}", v))
-            .and_then(|s| Uuid::parse_str(s).map_err(|e| format!("Failed to parse Uuid: {}", e)))
-            .map_err(Into::into)
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
+            .and_then(|s| Uuid::parse_str(s).map_err(|e| format!("Failed to parse `Uuid`: {}", e)))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/lib.rs b/juniper/src/lib.rs
index 365261e2e..259936739 100644
--- a/juniper/src/lib.rs
+++ b/juniper/src/lib.rs
@@ -163,7 +163,7 @@ pub use crate::{
     introspection::IntrospectionFormat,
     macros::helper::{
         subscription::{ExtractTypeFromStream, IntoFieldResult},
-        AsDynGraphQLValue, ExtractErrorFromResult,
+        AsDynGraphQLValue, ExtractError,
     },
     parser::{ParseError, Spanning},
     schema::{
diff --git a/juniper/src/macros/helper/mod.rs b/juniper/src/macros/helper/mod.rs
index 89249a7a9..0bd728fb2 100644
--- a/juniper/src/macros/helper/mod.rs
+++ b/juniper/src/macros/helper/mod.rs
@@ -33,17 +33,18 @@ pub trait AsDynGraphQLValue<S: ScalarValue = DefaultScalarValue> {
 
 crate::sa::assert_obj_safe!(AsDynGraphQLValue<Context = (), TypeInfo = ()>);
 
-/// This trait is used in `juniper::graphql_scalar` macro to get [`Error`] type
+/// This trait is used by [`graphql_scalar!`] macro to retrieve [`Error`] type
 /// from a [`Result`].
 ///
 /// [`Error`]: Result::Error
-pub trait ExtractErrorFromResult {
-    /// [`Error`] of a [`Result`].
+/// [`graphql_scalar!`]: macro@crate::graphql_scalar
+pub trait ExtractError {
+    /// Extracted [`Error`] type of this [`Result`].
     ///
     /// [`Error`]: Result::Error
     type Error;
 }
 
-impl<T, E> ExtractErrorFromResult for Result<T, E> {
+impl<T, E> ExtractError for Result<T, E> {
     type Error = E;
 }
diff --git a/juniper/src/schema/meta.rs b/juniper/src/schema/meta.rs
index c20e21e52..fdb6e50b5 100644
--- a/juniper/src/schema/meta.rs
+++ b/juniper/src/schema/meta.rs
@@ -1,5 +1,6 @@
 //! Types used to describe a `GraphQL` schema
 
+use juniper::IntoFieldError;
 use std::{
     borrow::{Cow, ToOwned},
     fmt,
@@ -11,6 +12,7 @@ use crate::{
     schema::model::SchemaType,
     types::base::TypeKind,
     value::{DefaultScalarValue, ParseScalarValue},
+    FieldError,
 };
 
 /// Whether an item is deprecated, with context.
@@ -46,7 +48,7 @@ pub struct ScalarMeta<'a, S> {
     pub name: Cow<'a, str>,
     #[doc(hidden)]
     pub description: Option<String>,
-    pub(crate) try_parse_fn: for<'b> fn(&'b InputValue<S>) -> bool,
+    pub(crate) try_parse_fn: for<'b> fn(&'b InputValue<S>) -> Result<(), FieldError<S>>,
     pub(crate) parse_fn: for<'b> fn(ScalarToken<'b>) -> Result<S, ParseError<'b>>,
 }
 
@@ -88,7 +90,7 @@ pub struct EnumMeta<'a, S> {
     pub description: Option<String>,
     #[doc(hidden)]
     pub values: Vec<EnumValue>,
-    pub(crate) try_parse_fn: for<'b> fn(&'b InputValue<S>) -> bool,
+    pub(crate) try_parse_fn: for<'b> fn(&'b InputValue<S>) -> Result<(), FieldError<S>>,
 }
 
 /// Interface type metadata
@@ -121,7 +123,7 @@ pub struct InputObjectMeta<'a, S> {
     pub description: Option<String>,
     #[doc(hidden)]
     pub input_fields: Vec<Argument<'a, S>>,
-    pub(crate) try_parse_fn: for<'b> fn(&'b InputValue<S>) -> bool,
+    pub(crate) try_parse_fn: for<'b> fn(&'b InputValue<S>) -> Result<(), FieldError<S>>,
 }
 
 /// A placeholder for not-yet-registered types
@@ -323,7 +325,9 @@ impl<'a, S> MetaType<'a, S> {
     /// `true` if it can be parsed as the provided type.
     ///
     /// Only scalars, enums, and input objects have parse functions.
-    pub fn input_value_parse_fn(&self) -> Option<for<'b> fn(&'b InputValue<S>) -> bool> {
+    pub fn input_value_parse_fn(
+        &self,
+    ) -> Option<for<'b> fn(&'b InputValue<S>) -> Result<(), FieldError<S>>> {
         match *self {
             MetaType::Scalar(ScalarMeta {
                 ref try_parse_fn, ..
@@ -412,6 +416,7 @@ impl<'a, S> ScalarMeta<'a, S> {
     pub fn new<T>(name: Cow<'a, str>) -> Self
     where
         T: FromInputValue<S> + ParseScalarValue<S>,
+        T::Error: IntoFieldError<S>,
     {
         Self {
             name,
@@ -510,6 +515,7 @@ impl<'a, S> EnumMeta<'a, S> {
     pub fn new<T>(name: Cow<'a, str>, values: &[EnumValue]) -> Self
     where
         T: FromInputValue<S>,
+        T::Error: IntoFieldError<S>,
     {
         Self {
             name,
@@ -595,6 +601,7 @@ impl<'a, S> InputObjectMeta<'a, S> {
     pub fn new<T>(name: Cow<'a, str>, input_fields: &[Argument<'a, S>]) -> Self
     where
         T: FromInputValue<S>,
+        T::Error: IntoFieldError<S>,
         S: Clone,
     {
         Self {
@@ -736,9 +743,12 @@ impl<'a, S: fmt::Debug> fmt::Debug for InputObjectMeta<'a, S> {
     }
 }
 
-fn try_parse_fn<S, T>(v: &InputValue<S>) -> bool
+fn try_parse_fn<S, T>(v: &InputValue<S>) -> Result<(), FieldError<S>>
 where
     T: FromInputValue<S>,
+    T::Error: IntoFieldError<S>,
 {
-    T::from_input_value(v).is_ok()
+    T::from_input_value(v)
+        .map(drop)
+        .map_err(T::Error::into_field_error)
 }
diff --git a/juniper/src/types/containers.rs b/juniper/src/types/containers.rs
index 14816194c..5ec67b9e8 100644
--- a/juniper/src/types/containers.rs
+++ b/juniper/src/types/containers.rs
@@ -1,5 +1,4 @@
 use std::{
-    array,
     mem::{self, MaybeUninit},
     ptr,
 };
@@ -86,7 +85,7 @@ impl<S, T: FromInputValue<S>> FromInputValue<S> for Option<T> {
 
     fn from_input_value(v: &InputValue<S>) -> Result<Self, Self::Error> {
         match v {
-            &InputValue::Null => Ok(None),
+            InputValue::Null => Ok(None),
             v => v.convert().map(Some),
         }
     }
@@ -166,6 +165,7 @@ impl<S, T: FromInputValue<S>> FromInputValue<S> for Vec<T> {
             InputValue::List(l) => l.iter().map(|i| i.item.convert()).collect(),
             // See "Input Coercion" on List types:
             // https://spec.graphql.org/June2018/#sec-Type-System.List
+            // In reality is intercepted by `Option`.
             InputValue::Null => Ok(Vec::new()),
             other => other.convert().map(|e| vec![e]),
         }
@@ -306,43 +306,6 @@ where
     }
 }
 
-/// Error converting [`InputValue`] into exact-size [`array`](prim@array).
-pub enum FromInputValueArrayError<T, S>
-where
-    T: FromInputValue<S>,
-    S: ScalarValue,
-{
-    /// Not enough elements.
-    NotEnough(usize),
-
-    /// Too many elements. Contains __all__ [`InputValue`] elements.
-    TooMuch(Vec<T>),
-
-    /// Underlying [`ScalarValue`] conversion error.
-    Scalar(T::Error),
-}
-
-impl<T, S> IntoFieldError<S> for FromInputValueArrayError<T, S>
-where
-    T: FromInputValue<S>,
-    T::Error: IntoFieldError<S>,
-    S: ScalarValue,
-{
-    fn into_field_error(self) -> FieldError<S> {
-        const ERROR_PREFIX: &str = "Failed to convert into exact-size array";
-
-        match self {
-            Self::NotEnough(len) => {
-                format!("{}: required {} more elements", ERROR_PREFIX, len).into()
-            }
-            Self::TooMuch(el) => {
-                format!("{}: too much elements: {}", ERROR_PREFIX, el.len()).into()
-            }
-            Self::Scalar(s) => s.into_field_error(),
-        }
-    }
-}
-
 impl<T, S, const N: usize> FromInputValue<S> for [T; N]
 where
     T: FromInputValue<S>,
@@ -377,6 +340,22 @@ where
 
         match *v {
             InputValue::List(ref ls) => {
+                if ls.len() != N {
+                    return Err(FromInputValueArrayError::WrongCount {
+                        actual: ls.len(),
+                        expected: N,
+                    });
+                }
+                if N == 0 {
+                    // TODO: Use `mem::transmute` instead of
+                    //       `mem::transmute_copy` below, once it's allowed
+                    //       for const generics:
+                    //       https://github.com/rust-lang/rust/issues/61956
+                    // SAFETY: `mem::transmute_copy` is safe here, because we
+                    //         check `N` to be `0`. It's no-op, actually.
+                    return Ok(unsafe { mem::transmute_copy::<[T; 0], Self>(&[]) });
+                }
+
                 // SAFETY: The reason we're using a wrapper struct implementing
                 //         `Drop` here is to be panic safe:
                 //         `T: FromInputValue<S>` implementation is not
@@ -396,7 +375,7 @@ where
                 };
 
                 let mut items = ls.iter().map(|i| i.item.convert());
-                for (id, elem) in out.arr.iter_mut().enumerate() {
+                for elem in &mut out.arr[..] {
                     if let Some(i) = items
                         .next()
                         .transpose()
@@ -404,8 +383,6 @@ where
                     {
                         *elem = MaybeUninit::new(i);
                         out.init_len += 1;
-                    } else {
-                        return Err(FromInputValueArrayError::NotEnough(N - id));
                     }
                 }
 
@@ -422,19 +399,19 @@ where
                 //         we won't have a double-free when `T: Drop` here,
                 //         because original array elements are `MaybeUninit`, so
                 //         do nothing on `Drop`.
-                let arr = unsafe { mem::transmute_copy::<_, Self>(&out.arr) };
-
-                if items.len() > 0 {
-                    return Err(FromInputValueArrayError::TooMuch(
-                        array::IntoIter::new(arr)
-                            .map(Ok)
-                            .chain(items)
-                            .collect::<Result<_, _>>()
-                            .map_err(FromInputValueArrayError::Scalar)?,
-                    ));
-                }
-
-                Ok(arr)
+                Ok(unsafe { mem::transmute_copy::<_, Self>(&out.arr) })
+            }
+            // See "Input Coercion" on List types:
+            // https://spec.graphql.org/June2018/#sec-Type-System.List
+            // In reality is intercepted by `Option`.
+            InputValue::Null if N == 0 => {
+                // TODO: Use `mem::transmute` instead of
+                //       `mem::transmute_copy` below, once it's allowed
+                //       for const generics:
+                //       https://github.com/rust-lang/rust/issues/61956
+                // SAFETY: `mem::transmute_copy` is safe here, because we check
+                //         `N` to be `0`. It's no-op, actually.
+                Ok(unsafe { mem::transmute_copy::<[T; 0], Self>(&[]) })
             }
             ref other => {
                 other
@@ -442,24 +419,26 @@ where
                     .map_err(FromInputValueArrayError::Scalar)
                     .and_then(|e: T| {
                         // TODO: Use `mem::transmute` instead of
-                        //       `mem::transmute_copy` below, once it's allowed for
-                        //       const generics:
+                        //       `mem::transmute_copy` below, once it's allowed
+                        //       for const generics:
                         //       https://github.com/rust-lang/rust/issues/61956
                         if N == 1 {
-                            // SAFETY: `mem::transmute_copy` is safe here, because
-                            //         we check `N` to be `1`.
-                            //         Also, despite `mem::transmute_copy` copies
-                            //         the value, we won't have a double-free when
-                            //         `T: Drop` here, because original `e: T` value
-                            //         is wrapped into `mem::ManuallyDrop`, so does
-                            //         nothing on `Drop`.
+                            // SAFETY: `mem::transmute_copy` is safe here,
+                            //         because we check `N` to be `1`.
+                            //         Also, despite `mem::transmute_copy`
+                            //         copies the value, we won't have a
+                            //         double-free when `T: Drop` here, because
+                            //         original `e: T` value is wrapped into
+                            //         `mem::ManuallyDrop`, so does nothing on
+                            //         `Drop`.
                             Ok(unsafe {
                                 mem::transmute_copy::<_, Self>(&[mem::ManuallyDrop::new(e)])
                             })
-                        } else if N == 0 {
-                            Err(FromInputValueArrayError::TooMuch(vec![e]))
                         } else {
-                            Err(FromInputValueArrayError::NotEnough(N - 1))
+                            Err(FromInputValueArrayError::WrongCount {
+                                actual: 1,
+                                expected: N,
+                            })
                         }
                     })
             }
@@ -477,6 +456,44 @@ where
     }
 }
 
+/// Error converting [`InputValue`] into exact-size [`array`](prim@array).
+pub enum FromInputValueArrayError<T, S>
+where
+    T: FromInputValue<S>,
+    S: ScalarValue,
+{
+    /// Wrong count of elements.
+    WrongCount {
+        /// Actual count of elements.
+        actual: usize,
+
+        /// Expected count of elements.
+        expected: usize,
+    },
+
+    /// Underlying [`ScalarValue`] conversion error.
+    Scalar(T::Error),
+}
+
+impl<T, S> IntoFieldError<S> for FromInputValueArrayError<T, S>
+where
+    T: FromInputValue<S>,
+    T::Error: IntoFieldError<S>,
+    S: ScalarValue,
+{
+    fn into_field_error(self) -> FieldError<S> {
+        const ERROR_PREFIX: &str = "Failed to convert into exact-size array";
+        match self {
+            Self::WrongCount { actual, expected } => format!(
+                "{}: wrong elements count: {} instead of {}",
+                ERROR_PREFIX, actual, expected
+            )
+            .into(),
+            Self::Scalar(s) => s.into_field_error(),
+        }
+    }
+}
+
 fn resolve_into_list<'t, S, T, I>(
     executor: &Executor<T::Context, S>,
     info: &T::TypeInfo,
@@ -543,7 +560,7 @@ where
 
 #[cfg(test)]
 mod coercion {
-    use crate::{FromInputValue as _, InputValue};
+    use crate::{graphql_input_value, FromInputValue as _, InputValue};
 
     type V = InputValue;
 
@@ -552,7 +569,7 @@ mod coercion {
     #[test]
     fn vec() {
         assert_eq!(
-            <Vec<i32>>::from_input_value(&V::list(vec![V::scalar(1), V::scalar(2), V::scalar(3)])),
+            <Vec<i32>>::from_input_value(&graphql_input_value!([1, 2, 3])),
             Ok(vec![1, 2, 3]),
         );
         // TODO: all examples
diff --git a/juniper/src/types/scalars.rs b/juniper/src/types/scalars.rs
index 83039aba6..d55c6ac3d 100644
--- a/juniper/src/types/scalars.rs
+++ b/juniper/src/types/scalars.rs
@@ -6,7 +6,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::{
     ast::{InputValue, Selection, ToInputValue},
-    executor::{ExecutionResult, Executor, FieldError, Registry},
+    executor::{ExecutionResult, Executor, Registry},
     parser::{LexerError, ParseError, ScalarToken, Token},
     schema::meta::MetaType,
     types::{
@@ -59,12 +59,12 @@ where
         Value::scalar(self.0.clone())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<ID, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<ID, String> {
         v.as_string_value()
             .map(str::to_owned)
             .or_else(|| v.as_int_value().map(|i| i.to_string()))
-            .ok_or_else(|| format!("Expected String or Int, found: {}", v).into())
             .map(ID)
+            .ok_or_else(|| format!("Expected `String` or `Int`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -84,10 +84,10 @@ where
         Value::scalar(self.clone())
     }
 
-    fn from_input_value(v: &InputValue) -> Result<String, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<String, String> {
         v.as_string_value()
             .map(str::to_owned)
-            .ok_or_else(|| format!("Expected String, found: {}", v).into())
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -272,10 +272,10 @@ where
         Value::scalar(*self)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<bool, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<bool, String> {
         v.as_scalar_value()
             .and_then(ScalarValue::as_boolean)
-            .ok_or_else(|| format!("Expected Boolean, found: {}", v).into())
+            .ok_or_else(|| format!("Expected `Boolean`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -293,9 +293,9 @@ where
         Value::scalar(*self)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<i32, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<i32, String> {
         v.as_int_value()
-            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
+            .ok_or_else(|| format!("Expected `Int`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -318,9 +318,9 @@ where
         Value::scalar(*self)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<f64, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<f64, String> {
         v.as_float_value()
-            .ok_or_else(|| format!("Expected Float, found: {}", v).into())
+            .ok_or_else(|| format!("Expected `Float`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
diff --git a/juniper/src/types/utilities.rs b/juniper/src/types/utilities.rs
index 1d1ec5fd6..2ed03b1f3 100644
--- a/juniper/src/types/utilities.rs
+++ b/juniper/src/types/utilities.rs
@@ -57,7 +57,7 @@ where
                 InputValue::Null | InputValue::Variable(_) => true,
                 ref v @ InputValue::Scalar(_) | ref v @ InputValue::Enum(_) => {
                     if let Some(parse_fn) = t.input_value_parse_fn() {
-                        parse_fn(v)
+                        parse_fn(v).is_ok()
                     } else {
                         false
                     }
diff --git a/juniper/src/validation/input_value.rs b/juniper/src/validation/input_value.rs
index ba6803a69..95f5d1350 100644
--- a/juniper/src/validation/input_value.rs
+++ b/juniper/src/validation/input_value.rs
@@ -163,14 +163,16 @@ where
                     if e.is_empty() {
                         // All the fields didn't have errors, see if there is an
                         // overall error when parsing the input value.
-                        if !(iom.try_parse_fn)(value) {
+                        if let Err(e) = (iom.try_parse_fn)(value) {
                             errors.push(unification_error(
                                 var_name,
                                 var_pos,
                                 &path,
                                 &format!(
-                                    r#"Expected input of type "{}". Got: "{}""#,
-                                    iom.name, value
+                                    "Expected input of type `{}`. Got: `{}`. Details: {}",
+                                    iom.name,
+                                    value,
+                                    e.message(),
                                 ),
                             ));
                         }
@@ -193,16 +195,21 @@ fn unify_scalar<'a, S>(
     path: &Path<'a>,
 ) -> Vec<RuleError>
 where
-    S: fmt::Debug,
+    S: ScalarValue,
 {
     let mut errors: Vec<RuleError> = vec![];
 
-    if !(meta.try_parse_fn)(value) {
+    if let Err(e) = (meta.try_parse_fn)(value) {
         return vec![unification_error(
             var_name,
             var_pos,
             path,
-            &format!(r#"Expected "{}""#, meta.name),
+            &format!(
+                "Expected input scalar `{}`. Got: `{}`. Details: {}",
+                meta.name,
+                value,
+                e.message(),
+            ),
         )];
     }
 
diff --git a/juniper/src/validation/test_harness.rs b/juniper/src/validation/test_harness.rs
index 0bff649c0..bcc0c7aae 100644
--- a/juniper/src/validation/test_harness.rs
+++ b/juniper/src/validation/test_harness.rs
@@ -2,7 +2,7 @@ use std::mem;
 
 use crate::{
     ast::{FromInputValue, InputValue},
-    executor::{FieldError, Registry},
+    executor::Registry,
     parser::parse_document_source,
     schema::{
         meta::{EnumValue, MetaType},
@@ -208,14 +208,14 @@ impl<S> FromInputValue<S> for DogCommand
 where
     S: ScalarValue,
 {
-    type Error = FieldError<S>;
+    type Error = &'static str;
 
     fn from_input_value<'a>(v: &InputValue<S>) -> Result<DogCommand, Self::Error> {
         match v.as_enum_value() {
             Some("SIT") => Ok(DogCommand::Sit),
             Some("HEEL") => Ok(DogCommand::Heel),
             Some("DOWN") => Ok(DogCommand::Down),
-            _ => Err("Unknown DogCommand".into()),
+            _ => Err("Unknown DogCommand"),
         }
     }
 }
@@ -316,7 +316,7 @@ impl<S> FromInputValue<S> for FurColor
 where
     S: ScalarValue,
 {
-    type Error = FieldError<S>;
+    type Error = &'static str;
 
     fn from_input_value<'a>(v: &InputValue<S>) -> Result<FurColor, Self::Error> {
         match v.as_enum_value() {
@@ -324,7 +324,7 @@ where
             Some("BLACK") => Ok(FurColor::Black),
             Some("TAN") => Ok(FurColor::Tan),
             Some("SPOTTED") => Ok(FurColor::Spotted),
-            _ => Err("Unknown FurColor".into()),
+            _ => Err("Unknown FurColor"),
         }
     }
 }
@@ -616,7 +616,7 @@ impl<S> FromInputValue<S> for ComplexInput
 where
     S: ScalarValue,
 {
-    type Error = FieldError<S>;
+    type Error = String;
 
     fn from_input_value<'a>(v: &InputValue<S>) -> Result<ComplexInput, Self::Error> {
         let obj = v.to_object_value().ok_or("Expected object")?;
@@ -624,27 +624,27 @@ where
         Ok(ComplexInput {
             required_field: obj
                 .get("requiredField")
-                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .map(|v| v.convert())
                 .transpose()?
                 .ok_or("Expected requiredField")?,
             int_field: obj
                 .get("intField")
-                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .map(|v| v.convert())
                 .transpose()?
                 .ok_or("Expected intField")?,
             string_field: obj
                 .get("stringField")
-                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .map(|v| v.convert())
                 .transpose()?
                 .ok_or("Expected stringField")?,
             boolean_field: obj
                 .get("booleanField")
-                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .map(|v| v.convert())
                 .transpose()?
                 .ok_or("Expected booleanField")?,
             string_list_field: obj
                 .get("stringListField")
-                .map(|v| v.convert().map_err(FieldError::map_scalar_value))
+                .map(|v| v.convert())
                 .transpose()?
                 .ok_or("Expected stringListField")?,
         })
diff --git a/juniper_codegen/src/graphql_union/mod.rs b/juniper_codegen/src/graphql_union/mod.rs
index 040ce97f4..299cb7c24 100644
--- a/juniper_codegen/src/graphql_union/mod.rs
+++ b/juniper_codegen/src/graphql_union/mod.rs
@@ -707,8 +707,8 @@ impl VariantDefinition {
                         return #resolving_code;
                     }
                 }
-                None => return Box::pin(::juniper::futures::future::ready(
-                    Err(::juniper::FieldError::from("This GraphQLType has no name"))
+                None => return Box::pin(::juniper::futures::future::err(
+                    ::juniper::FieldError::from("This GraphQLType has no name")
                 )),
             }
         }
diff --git a/juniper_codegen/src/impl_scalar.rs b/juniper_codegen/src/impl_scalar.rs
index f05ea91ba..7bf901c63 100644
--- a/juniper_codegen/src/impl_scalar.rs
+++ b/juniper_codegen/src/impl_scalar.rs
@@ -309,7 +309,7 @@ pub fn build_scalar(
         impl#generic_type_decl ::juniper::FromInputValue<#generic_type> for #impl_for_type
         #generic_type_bound
         {
-            type Error = <#from_input_value_result as ::juniper::ExtractErrorFromResult>::Error;
+            type Error = <#from_input_value_result as ::juniper::ExtractError>::Error;
 
             fn from_input_value(#from_input_value_arg: &::juniper::InputValue<#generic_type>) -> #from_input_value_result {
                 #from_input_value_body
diff --git a/juniper_codegen/src/lib.rs b/juniper_codegen/src/lib.rs
index b18b84702..b25967a6e 100644
--- a/juniper_codegen/src/lib.rs
+++ b/juniper_codegen/src/lib.rs
@@ -230,10 +230,11 @@ pub fn derive_scalar_value(input: TokenStream) -> TokenStream {
 ///         juniper::Value::scalar(self.0.to_owned())
 ///     }
 ///
-///     fn from_input_value(value: &juniper::InputValue) -> Result<UserID, juniper::FieldError> {
+///     // NOTE: The error type should implement `IntoFieldError<S>`.
+///     fn from_input_value(value: &juniper::InputValue) -> Result<UserID, String> {
 ///         value.as_string_value()
 ///             .map(|s| UserID(s.to_owned()))
-///             .ok_or_else(|| format!("Expected String, found: {}", value).into())
+///             .ok_or_else(|| format!("Expected String, found: {}", value))
 ///     }
 ///
 ///     fn from_str<'a>(value: juniper::ScalarToken<'a>) -> juniper::ParseScalarResult<'a, S> {
diff --git a/juniper_codegen/src/util/mod.rs b/juniper_codegen/src/util/mod.rs
index bb9bcbf44..a6083e073 100644
--- a/juniper_codegen/src/util/mod.rs
+++ b/juniper_codegen/src/util/mod.rs
@@ -860,18 +860,16 @@ impl GraphQLTypeDefiniton {
             impl#impl_generics ::juniper::FromInputValue<#scalar> for #ty
                 #where_clause
             {
-                type Error = ::juniper::FieldError<#scalar>;
+                type Error = ::std::string::String;
 
                 fn from_input_value(
                     v: &::juniper::InputValue<#scalar>
-                ) -> Result<#ty, ::juniper::FieldError<#scalar>> {
+                ) -> Result<#ty, Self::Error> {
                     match v.as_enum_value().or_else(|| {
                         v.as_string_value()
                     }) {
                         #( #from_inputs )*
-                        _ => Err(::juniper::FieldError::<#scalar>::from(
-                            format!("Unknown Enum value: {}", v))
-                        ),
+                        _ => Err(format!("Unknown enum value: {}", v)),
                     }
                 }
             }
@@ -986,7 +984,7 @@ impl GraphQLTypeDefiniton {
                         match obj.get(#field_name) {
                             #from_input_default
                             Some(ref v) => {
-                                ::juniper::FromInputValue::from_input_value(v)
+                                ::juniper::FromInputValue::<#scalar>::from_input_value(v)
                                     .map_err(::juniper::IntoFieldError::into_field_error)?
                             },
                             None => {
@@ -1111,10 +1109,11 @@ impl GraphQLTypeDefiniton {
 
                 fn from_input_value(
                     value: &::juniper::InputValue<#scalar>
-                ) -> Result<Self, ::juniper::FieldError<#scalar>> {
-                    let obj = value.to_object_value()
+                ) -> Result<Self, Self::Error> {
+                    let obj = value
+                        .to_object_value()
                         .ok_or_else(|| ::juniper::FieldError::<#scalar>::from(
-                            format!("Expected Object, found: {}", value))
+                            format!("Expected input object, found: {}", value))
                         )?;
                     Ok(#ty {
                         #( #from_inputs )*

From 3e438866556a955e6aa021231a2e5c025e2a0436 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Mon, 13 Dec 2021 08:05:47 +0300
Subject: [PATCH 16/25] Add tests

---
 .../rules/fields_on_correct_type.rs           | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/juniper/src/validation/rules/fields_on_correct_type.rs b/juniper/src/validation/rules/fields_on_correct_type.rs
index 68e6cc281..ecd9cf693 100644
--- a/juniper/src/validation/rules/fields_on_correct_type.rs
+++ b/juniper/src/validation/rules/fields_on_correct_type.rs
@@ -379,4 +379,28 @@ mod tests {
         "#,
         );
     }
+
+    #[test]
+    fn typename_on_subscription() {
+        expect_fails_rule::<_, _, DefaultScalarValue>(
+            factory,
+            r#"subscription { __typename }"#,
+            &[RuleError::new(
+                "`__typename` may not be included as a root field in a subscription operation",
+                &[SourcePosition::new(15, 0, 15)],
+            )],
+        );
+    }
+
+    #[test]
+    fn typename_on_explicit_subscription() {
+        expect_fails_rule::<_, _, DefaultScalarValue>(
+            factory,
+            r#"subscription SubscriptionRoot { __typename }"#,
+            &[RuleError::new(
+                "`__typename` may not be included as a root field in a subscription operation",
+                &[SourcePosition::new(32, 0, 32)],
+            )],
+        );
+    }
 }

From efca2c0f3027c0ce43537067cda46abf141e1e44 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Mon, 13 Dec 2021 08:41:10 +0300
Subject: [PATCH 17/25] Tests fixes

---
 .../fail/union/trait_fail_infer_context.stderr           | 9 +++++++--
 juniper/src/executor_tests/introspection/input_object.rs | 2 +-
 juniper/src/executor_tests/variables.rs                  | 9 ++++++---
 juniper/src/integrations/chrono_tz.rs                    | 8 ++++----
 juniper/src/parser/tests/value.rs                        | 5 +++--
 juniper/src/types/containers.rs                          | 6 ++----
 6 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/integration_tests/codegen_fail/fail/union/trait_fail_infer_context.stderr b/integration_tests/codegen_fail/fail/union/trait_fail_infer_context.stderr
index b4eb24816..e3e3b8065 100644
--- a/integration_tests/codegen_fail/fail/union/trait_fail_infer_context.stderr
+++ b/integration_tests/codegen_fail/fail/union/trait_fail_infer_context.stderr
@@ -1,8 +1,13 @@
 error[E0277]: the trait bound `CustomContext: FromContext<SubContext>` is not satisfied
    --> fail/union/trait_fail_infer_context.rs:3:1
     |
-3   | #[graphql_union]
-    | ^^^^^^^^^^^^^^^^ expected an implementor of trait `FromContext<SubContext>`
+3   |   #[graphql_union]
+    |   ^^^^^^^^^^^^^^^^ expected an implementor of trait `FromContext<SubContext>`
+4   |   trait Character {
+    |  _______-
+5   | |     fn a(&self, ctx: &SubContext) -> Option<&Human>;
+6   | |     fn b(&self, ctx: &CustomContext) -> Option<&Droid>;
+    | |________- required by a bound introduced by this call
     |
 note: required by `juniper::FromContext::from`
    --> $WORKSPACE/juniper/src/executor/mod.rs
diff --git a/juniper/src/executor_tests/introspection/input_object.rs b/juniper/src/executor_tests/introspection/input_object.rs
index b3451463c..d433681a5 100644
--- a/juniper/src/executor_tests/introspection/input_object.rs
+++ b/juniper/src/executor_tests/introspection/input_object.rs
@@ -206,7 +206,7 @@ fn default_name_input_value() {
 
     let dv = DefaultName::from_input_value(&iv);
 
-    assert!(dv.is_ok(), "error: {}", dv.unwrap_err());
+    assert!(dv.is_ok(), "error: {:?}", dv.unwrap_err());
 
     let dv = dv.unwrap();
 
diff --git a/juniper/src/executor_tests/variables.rs b/juniper/src/executor_tests/variables.rs
index f2e3bb818..6af5ef7f5 100644
--- a/juniper/src/executor_tests/variables.rs
+++ b/juniper/src/executor_tests/variables.rs
@@ -1072,7 +1072,8 @@ mod integers {
         assert_eq!(
             error,
             ValidationError(vec![RuleError::new(
-                r#"Variable "$var" got invalid value. Expected "Int"."#,
+                "Variable \"$var\" got invalid value. Expected input scalar `Int`. \
+                 Got: `10`. Details: Expected `Int`, found: 10.",
                 &[SourcePosition::new(8, 0, 8)],
             )]),
         );
@@ -1096,7 +1097,8 @@ mod integers {
         assert_eq!(
             error,
             ValidationError(vec![RuleError::new(
-                r#"Variable "$var" got invalid value. Expected "Int"."#,
+                "Variable \"$var\" got invalid value. Expected input scalar `Int`. \
+                 Got: `\"10\"`. Details: Expected `Int`, found: \"10\".",
                 &[SourcePosition::new(8, 0, 8)],
             )]),
         );
@@ -1154,7 +1156,8 @@ mod floats {
         assert_eq!(
             error,
             ValidationError(vec![RuleError::new(
-                r#"Variable "$var" got invalid value. Expected "Float"."#,
+                "Variable \"$var\" got invalid value. Expected input scalar `Float`. \
+                 Got: `\"10\"`. Details: Expected `Float`, found: \"10\".",
                 &[SourcePosition::new(8, 0, 8)],
             )]),
         );
diff --git a/juniper/src/integrations/chrono_tz.rs b/juniper/src/integrations/chrono_tz.rs
index 9947015fd..8fce3a97b 100644
--- a/juniper/src/integrations/chrono_tz.rs
+++ b/juniper/src/integrations/chrono_tz.rs
@@ -53,7 +53,7 @@ mod test {
             let parsed = FromInputValue::from_input_value(&input);
 
             assert_eq!(
-                parsed.as_ref().map_err(|e: &FieldError| e.message()),
+                parsed.as_ref().map_err(Deref::deref),
                 expected.as_ref().map_err(Deref::deref),
             );
         }
@@ -75,7 +75,7 @@ mod test {
             fn forward_slash() {
                 tz_input_test(
                     "Abc/Xyz",
-                    Err("Failed to parse `Timezone`: received invalid timezone"),
+                    Err("Failed to parse `Tz`: received invalid timezone"),
                 );
             }
 
@@ -83,7 +83,7 @@ mod test {
             fn number() {
                 tz_input_test(
                     "8086",
-                    Err("Failed to parse `Timezone`: received invalid timezone"),
+                    Err("Failed to parse `Tz`: received invalid timezone"),
                 );
             }
 
@@ -91,7 +91,7 @@ mod test {
             fn no_forward_slash() {
                 tz_input_test(
                     "AbcXyz",
-                    Err("Failed to parse `Timezone`: received invalid timezone"),
+                    Err("Failed to parse `Tz`: received invalid timezone"),
                 );
             }
         }
diff --git a/juniper/src/parser/tests/value.rs b/juniper/src/parser/tests/value.rs
index 0ce829000..8dbe78bd2 100644
--- a/juniper/src/parser/tests/value.rs
+++ b/juniper/src/parser/tests/value.rs
@@ -8,7 +8,7 @@ use crate::{
     },
     types::scalars::{EmptyMutation, EmptySubscription},
     value::{DefaultScalarValue, ParseScalarValue, ScalarValue},
-    GraphQLEnum, GraphQLInputObject,
+    GraphQLEnum, GraphQLInputObject, IntoFieldError,
 };
 
 #[derive(GraphQLEnum)]
@@ -52,9 +52,10 @@ impl Query {
     }
 }
 
-fn scalar_meta<T>(name: &'static str) -> MetaType<DefaultScalarValue>
+fn scalar_meta<T>(name: &'static str) -> MetaType
 where
     T: FromInputValue<DefaultScalarValue> + ParseScalarValue<DefaultScalarValue>,
+    T::Error: IntoFieldError,
 {
     MetaType::Scalar(ScalarMeta::new::<T>(name.into()))
 }
diff --git a/juniper/src/types/containers.rs b/juniper/src/types/containers.rs
index 5ec67b9e8..580a8c981 100644
--- a/juniper/src/types/containers.rs
+++ b/juniper/src/types/containers.rs
@@ -568,10 +568,8 @@ mod coercion {
     // https://spec.graphql.org/June2018/#sec-Type-System.List
     #[test]
     fn vec() {
-        assert_eq!(
-            <Vec<i32>>::from_input_value(&graphql_input_value!([1, 2, 3])),
-            Ok(vec![1, 2, 3]),
-        );
+        let v: V = graphql_input_value!([1, 2, 3]);
+        assert_eq!(<Vec<i32>>::from_input_value(&v), Ok(vec![1, 2, 3]),);
         // TODO: all examples
     }
 }

From 0112c1adae539f21e4caea664a8427bff2362494 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Mon, 13 Dec 2021 10:20:46 +0300
Subject: [PATCH 18/25] Upgrade actix

---
 juniper_actix/Cargo.toml | 12 +++---
 juniper_actix/src/lib.rs | 82 ++++++++++++++++++++++++++--------------
 2 files changed, 59 insertions(+), 35 deletions(-)

diff --git a/juniper_actix/Cargo.toml b/juniper_actix/Cargo.toml
index d5730bd7c..f3f4fd27f 100644
--- a/juniper_actix/Cargo.toml
+++ b/juniper_actix/Cargo.toml
@@ -13,10 +13,10 @@ subscriptions = ["juniper_graphql_ws", "tokio"]
 
 [dependencies]
 actix = "0.12"
-actix-http = "3.0.0-beta.13"
+actix-http = "3.0.0-beta.15"
 http = "0.2.4"
-actix-web = "4.0.0-beta.12"
-actix-web-actors = "4.0.0-beta.7"
+actix-web = "4.0.0-beta.14"
+actix-web-actors = "4.0.0-beta.8"
 
 juniper = { version = "0.15.7", path = "../juniper", default-features = false }
 juniper_graphql_ws = { version = "0.3.0", path = "../juniper_graphql_ws", optional = true }
@@ -30,11 +30,11 @@ tokio = { version = "1.0", features = ["sync"], optional = true }
 
 [dev-dependencies]
 actix-rt = "2"
-actix-cors = "0.6.0-beta.4"
-actix-identity = "0.4.0-beta.4"
+actix-cors = "0.6.0-beta.6"
+actix-identity = "0.4.0-beta.5"
 tokio = "1.0"
 async-stream = "0.3"
-actix-test = "0.1.0-beta.6"
+actix-test = "0.1.0-beta.8"
 
 juniper = { version = "0.15.7", path = "../juniper", features = ["expose-test-schema"] }
 
diff --git a/juniper_actix/src/lib.rs b/juniper_actix/src/lib.rs
index d1b89da5d..f22906b9f 100644
--- a/juniper_actix/src/lib.rs
+++ b/juniper_actix/src/lib.rs
@@ -466,7 +466,9 @@ pub mod subscriptions {
 
 #[cfg(test)]
 mod tests {
-    use actix_http::body::AnyBody;
+    use std::{future::Future, pin::Pin, task};
+
+    use actix_http::body::{BoxBody, MessageBody};
     use actix_web::{
         dev::ServiceResponse,
         http,
@@ -475,6 +477,7 @@ mod tests {
         web::Data,
         App,
     };
+    use bytes::Bytes;
     use juniper::{
         http::tests::{run_http_test_suite, HttpIntegration, TestResponse},
         tests::fixtures::starwars::schema::{Database, Query},
@@ -487,13 +490,27 @@ mod tests {
     type Schema =
         juniper::RootNode<'static, Query, EmptyMutation<Database>, EmptySubscription<Database>>;
 
-    async fn take_response_body_string(resp: &mut ServiceResponse) -> String {
-        match resp.response().body() {
-            AnyBody::Bytes(body) => String::from_utf8(body.to_vec()).unwrap(),
-            _ => String::from(""),
+    struct BoxBodyFuture(BoxBody);
+
+    impl Future for BoxBodyFuture {
+        type Output = Option<Result<Bytes, actix_http::Error>>;
+
+        fn poll(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> task::Poll<Self::Output> {
+            Pin::new(&mut self.get_mut().0).poll_next(cx)
         }
     }
 
+    async fn take_response_body_string(resp: ServiceResponse) -> String {
+        String::from_utf8(
+            BoxBodyFuture(resp.into_body())
+                .await
+                .unwrap()
+                .unwrap()
+                .to_vec(),
+        )
+        .unwrap()
+    }
+
     async fn index(
         req: HttpRequest,
         payload: actix_web::web::Payload,
@@ -537,13 +554,13 @@ mod tests {
             .append_header((ACCEPT, "text/html"))
             .to_request();
 
-        let mut resp = test::call_service(&mut app, req).await;
-        let body = take_response_body_string(&mut resp).await;
+        let resp = test::call_service(&mut app, req).await;
         assert_eq!(resp.status(), http::StatusCode::OK);
         assert_eq!(
             resp.headers().get(CONTENT_TYPE).unwrap().to_str().unwrap(),
             "text/html; charset=utf-8"
         );
+        let body = take_response_body_string(resp).await;
         assert!(body.contains("<script>var GRAPHQL_URL = '/dogs-api/graphql';</script>"));
         assert!(body.contains(
             "<script>var GRAPHQL_SUBSCRIPTIONS_URL = '/dogs-api/subscriptions';</script>"
@@ -578,13 +595,13 @@ mod tests {
             .append_header((ACCEPT, "text/html"))
             .to_request();
 
-        let mut resp = test::call_service(&mut app, req).await;
-        let body = take_response_body_string(&mut resp).await;
+        let resp = test::call_service(&mut app, req).await;
         assert_eq!(resp.status(), http::StatusCode::OK);
         assert_eq!(
             resp.headers().get(CONTENT_TYPE).unwrap().to_str().unwrap(),
             "text/html; charset=utf-8"
         );
+        let body = take_response_body_string(resp).await;
         assert!(body.contains("GraphQLPlayground.init(root, { endpoint: '/dogs-api/graphql', subscriptionEndpoint: '/dogs-api/subscriptions' })"));
     }
 
@@ -611,17 +628,17 @@ mod tests {
         )
         .await;
 
-        let mut resp = test::call_service(&mut app, req).await;
-        dbg!(take_response_body_string(&mut resp).await);
+        let resp = test::call_service(&mut app, req).await;
         assert_eq!(resp.status(), http::StatusCode::OK);
-        assert_eq!(
-            take_response_body_string(&mut resp).await,
-            r#"{"data":{"hero":{"name":"R2-D2"}}}"#
-        );
         assert_eq!(
             resp.headers().get("content-type").unwrap(),
             "application/json",
         );
+
+        assert_eq!(
+            take_response_body_string(resp).await,
+            r#"{"data":{"hero":{"name":"R2-D2"}}}"#
+        );
     }
 
     #[actix_web::rt::test]
@@ -644,17 +661,18 @@ mod tests {
         )
         .await;
 
-        let mut resp = test::call_service(&mut app, req).await;
+        let resp = test::call_service(&mut app, req).await;
 
         assert_eq!(resp.status(), http::StatusCode::OK);
-        assert_eq!(
-            take_response_body_string(&mut resp).await,
-            r#"{"data":{"hero":{"name":"R2-D2"}}}"#
-        );
         assert_eq!(
             resp.headers().get("content-type").unwrap(),
             "application/json",
         );
+
+        assert_eq!(
+            take_response_body_string(resp).await,
+            r#"{"data":{"hero":{"name":"R2-D2"}}}"#
+        );
     }
 
     #[actix_web::rt::test]
@@ -688,17 +706,17 @@ mod tests {
         )
         .await;
 
-        let mut resp = test::call_service(&mut app, req).await;
+        let resp = test::call_service(&mut app, req).await;
 
         assert_eq!(resp.status(), http::StatusCode::OK);
-        assert_eq!(
-            take_response_body_string(&mut resp).await,
-            r#"[{"data":{"hero":{"name":"R2-D2"}}},{"data":{"hero":{"id":"1000","name":"Luke Skywalker"}}}]"#
-        );
         assert_eq!(
             resp.headers().get("content-type").unwrap(),
             "application/json",
         );
+        assert_eq!(
+            take_response_body_string(resp).await,
+            r#"[{"data":{"hero":{"name":"R2-D2"}}},{"data":{"hero":{"id":"1000","name":"Luke Skywalker"}}}]"#
+        );
     }
 
     #[test]
@@ -757,14 +775,20 @@ mod tests {
         }
     }
 
-    async fn make_test_response(mut resp: ServiceResponse) -> TestResponse {
-        let body = take_response_body_string(&mut resp).await;
+    async fn make_test_response(resp: ServiceResponse) -> TestResponse {
         let status_code = resp.status().as_u16();
-        let content_type = resp.headers().get(CONTENT_TYPE).unwrap();
+        let content_type = resp
+            .headers()
+            .get(CONTENT_TYPE)
+            .unwrap()
+            .to_str()
+            .unwrap()
+            .to_string();
+        let body = take_response_body_string(resp).await;
         TestResponse {
             status_code: status_code as i32,
             body: Some(body),
-            content_type: content_type.to_str().unwrap().to_string(),
+            content_type,
         }
     }
 

From 7006d5838f6bf5ac4e3b27207bb7589b518aa14f Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Mon, 13 Dec 2021 10:33:36 +0300
Subject: [PATCH 19/25] Use poll_fn()

---
 juniper_actix/src/lib.rs | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/juniper_actix/src/lib.rs b/juniper_actix/src/lib.rs
index f22906b9f..de870df80 100644
--- a/juniper_actix/src/lib.rs
+++ b/juniper_actix/src/lib.rs
@@ -466,9 +466,9 @@ pub mod subscriptions {
 
 #[cfg(test)]
 mod tests {
-    use std::{future::Future, pin::Pin, task};
+    use std::pin::Pin;
 
-    use actix_http::body::{BoxBody, MessageBody};
+    use actix_http::body::MessageBody;
     use actix_web::{
         dev::ServiceResponse,
         http,
@@ -477,7 +477,7 @@ mod tests {
         web::Data,
         App,
     };
-    use bytes::Bytes;
+    use futures::future;
     use juniper::{
         http::tests::{run_http_test_suite, HttpIntegration, TestResponse},
         tests::fixtures::starwars::schema::{Database, Query},
@@ -490,19 +490,10 @@ mod tests {
     type Schema =
         juniper::RootNode<'static, Query, EmptyMutation<Database>, EmptySubscription<Database>>;
 
-    struct BoxBodyFuture(BoxBody);
-
-    impl Future for BoxBodyFuture {
-        type Output = Option<Result<Bytes, actix_http::Error>>;
-
-        fn poll(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> task::Poll<Self::Output> {
-            Pin::new(&mut self.get_mut().0).poll_next(cx)
-        }
-    }
-
     async fn take_response_body_string(resp: ServiceResponse) -> String {
+        let mut body = resp.into_body();
         String::from_utf8(
-            BoxBodyFuture(resp.into_body())
+            future::poll_fn(|cx| Pin::new(&mut body).poll_next(cx))
                 .await
                 .unwrap()
                 .unwrap()

From f2dbec323d934fcf51e65d179f084eb5f8b84abb Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Mon, 13 Dec 2021 11:29:57 +0300
Subject: [PATCH 20/25] Add boxed_field_err_fut

---
 docs/book/content/types/scalars.md       |  4 ++--
 juniper/src/macros/helper/mod.rs         | 14 +++++++++++++-
 juniper_codegen/src/graphql_union/mod.rs | 14 +++++++-------
 3 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/docs/book/content/types/scalars.md b/docs/book/content/types/scalars.md
index c6ce47134..857a1d020 100644
--- a/docs/book/content/types/scalars.md
+++ b/docs/book/content/types/scalars.md
@@ -128,11 +128,11 @@ where
     }
 
     // Define how to parse a primitive type into your custom scalar.
-    fn from_input_value(v: &InputValue) -> Result<Date, FieldError<S>> {
+    // NOTE: The error type should implement `IntoFieldError<S>`.
+    fn from_input_value(v: &InputValue) -> Result<Date, String> {
         v.as_string_value()
         .ok_or_else(|| format!("Expected String, found: {}", v))
         .and_then(|s| s.parse().map_err(|e| format!("Failed to parse Date: {}", e)))
-        .map_err(Into::into)
     }
 
     // Define how to parse a string value.
diff --git a/juniper/src/macros/helper/mod.rs b/juniper/src/macros/helper/mod.rs
index 0bd728fb2..8ae7d10d7 100644
--- a/juniper/src/macros/helper/mod.rs
+++ b/juniper/src/macros/helper/mod.rs
@@ -2,7 +2,19 @@
 
 pub mod subscription;
 
-use crate::{DefaultScalarValue, DynGraphQLValue, DynGraphQLValueAsync, ScalarValue};
+use std::{fmt::Display, future::Future, pin::Pin};
+
+use futures::future;
+
+use crate::{DefaultScalarValue, DynGraphQLValue, DynGraphQLValueAsync, FieldError, ScalarValue};
+
+/// Wraps `msg` with [`Display`] implementation into opaque [`Future`] which
+/// immediately resolves into [`FieldError`].
+pub fn boxed_field_err_fut<D: Display, Ok, S>(
+    msg: D,
+) -> Pin<Box<dyn Future<Output = Result<Ok, FieldError<S>>>>> {
+    Box::pin(future::err(FieldError::from(msg)))
+}
 
 /// Conversion of a [`GraphQLValue`] to its [trait object][1].
 ///
diff --git a/juniper_codegen/src/graphql_union/mod.rs b/juniper_codegen/src/graphql_union/mod.rs
index 299cb7c24..d36d546a3 100644
--- a/juniper_codegen/src/graphql_union/mod.rs
+++ b/juniper_codegen/src/graphql_union/mod.rs
@@ -602,13 +602,13 @@ impl Definition {
                     let context = executor.context();
                     #( #variant_async_resolvers )*
 
-                    return Box::pin(::juniper::futures::future::ready(
-                        Err(::juniper::FieldError::from(format!(
+                    return ::juniper::macros::helper::boxed_field_err_fut(
+                        format!(
                             "Concrete type `{}` is not handled by instance \
                             resolvers on GraphQL union `{}`",
                             type_name, #name,
-                        )))
-                    ));
+                        )
+                    );
                 }
             }
         }
@@ -707,9 +707,9 @@ impl VariantDefinition {
                         return #resolving_code;
                     }
                 }
-                None => return Box::pin(::juniper::futures::future::err(
-                    ::juniper::FieldError::from("This GraphQLType has no name")
-                )),
+                None => return ::juniper::macros::helper::field_err_boxed_fut(
+                    "This GraphQLType has no name"
+                ),
             }
         }
     }

From 91a91a1d328fecb449de2ba500be0a8fbc7e4862 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Mon, 13 Dec 2021 13:35:47 +0300
Subject: [PATCH 21/25] Corrections

---
 juniper/src/lib.rs                       |  1 +
 juniper/src/macros/helper/mod.rs         |  7 ++++---
 juniper_codegen/src/graphql_union/mod.rs | 14 ++++++--------
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/juniper/src/lib.rs b/juniper/src/lib.rs
index 259936739..c63931d68 100644
--- a/juniper/src/lib.rs
+++ b/juniper/src/lib.rs
@@ -162,6 +162,7 @@ pub use crate::{
     },
     introspection::IntrospectionFormat,
     macros::helper::{
+        field_err_boxed_fut,
         subscription::{ExtractTypeFromStream, IntoFieldResult},
         AsDynGraphQLValue, ExtractError,
     },
diff --git a/juniper/src/macros/helper/mod.rs b/juniper/src/macros/helper/mod.rs
index 8ae7d10d7..549ca0d4b 100644
--- a/juniper/src/macros/helper/mod.rs
+++ b/juniper/src/macros/helper/mod.rs
@@ -4,15 +4,16 @@ pub mod subscription;
 
 use std::{fmt::Display, future::Future, pin::Pin};
 
-use futures::future;
+use futures::future::{self, BoxFuture};
 
 use crate::{DefaultScalarValue, DynGraphQLValue, DynGraphQLValueAsync, FieldError, ScalarValue};
 
 /// Wraps `msg` with [`Display`] implementation into opaque [`Future`] which
 /// immediately resolves into [`FieldError`].
-pub fn boxed_field_err_fut<D: Display, Ok, S>(
+#[doc(hidden)]
+pub fn field_err_boxed_fut<'ok, D: Display, Ok: 'ok, S: 'static>(
     msg: D,
-) -> Pin<Box<dyn Future<Output = Result<Ok, FieldError<S>>>>> {
+) -> BoxFuture<'ok, Result<Ok, FieldError<S>>> {
     Box::pin(future::err(FieldError::from(msg)))
 }
 
diff --git a/juniper_codegen/src/graphql_union/mod.rs b/juniper_codegen/src/graphql_union/mod.rs
index d36d546a3..9d2ae57fb 100644
--- a/juniper_codegen/src/graphql_union/mod.rs
+++ b/juniper_codegen/src/graphql_union/mod.rs
@@ -602,13 +602,11 @@ impl Definition {
                     let context = executor.context();
                     #( #variant_async_resolvers )*
 
-                    return ::juniper::macros::helper::boxed_field_err_fut(
-                        format!(
-                            "Concrete type `{}` is not handled by instance \
-                            resolvers on GraphQL union `{}`",
-                            type_name, #name,
-                        )
-                    );
+                    return ::juniper::field_err_boxed_fut(format!(
+                        "Concrete type `{}` is not handled by instance \
+                        resolvers on GraphQL union `{}`",
+                        type_name, #name,
+                    ));
                 }
             }
         }
@@ -707,7 +705,7 @@ impl VariantDefinition {
                         return #resolving_code;
                     }
                 }
-                None => return ::juniper::macros::helper::field_err_boxed_fut(
+                None => return ::juniper::field_err_boxed_fut(
                     "This GraphQLType has no name"
                 ),
             }

From dd807359c5c703fc05b12fd80912cb83e53458c8 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Mon, 13 Dec 2021 13:56:09 +0300
Subject: [PATCH 22/25] Corrections

---
 juniper/src/macros/helper/mod.rs | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/juniper/src/macros/helper/mod.rs b/juniper/src/macros/helper/mod.rs
index 549ca0d4b..2715ff140 100644
--- a/juniper/src/macros/helper/mod.rs
+++ b/juniper/src/macros/helper/mod.rs
@@ -2,18 +2,21 @@
 
 pub mod subscription;
 
-use std::{fmt::Display, future::Future, pin::Pin};
+use std::fmt::Display;
 
 use futures::future::{self, BoxFuture};
 
 use crate::{DefaultScalarValue, DynGraphQLValue, DynGraphQLValueAsync, FieldError, ScalarValue};
 
-/// Wraps `msg` with [`Display`] implementation into opaque [`Future`] which
-/// immediately resolves into [`FieldError`].
+/// Wraps `msg` with [`Display`] implementation into opaque [`Send`] [`Future`]
+/// which immediately resolves into [`FieldError`].
 #[doc(hidden)]
-pub fn field_err_boxed_fut<'ok, D: Display, Ok: 'ok, S: 'static>(
-    msg: D,
-) -> BoxFuture<'ok, Result<Ok, FieldError<S>>> {
+pub fn field_err_boxed_fut<'ok, D, Ok, S>(msg: D) -> BoxFuture<'ok, Result<Ok, FieldError<S>>>
+where
+    D: Display,
+    Ok: Send + 'ok,
+    S: Send + 'static,
+{
     Box::pin(future::err(FieldError::from(msg)))
 }
 

From 00ff1df118080923956f4fd7b1d10f83beb3b60e Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Tue, 14 Dec 2021 10:30:25 +0300
Subject: [PATCH 23/25] Corrections

---
 docs/book/content/types/scalars.md            |  4 +--
 .../juniper_tests/src/codegen/impl_scalar.rs  | 31 +++++++++----------
 .../juniper_tests/src/custom_scalar.rs        |  8 ++---
 juniper_codegen/src/graphql_interface/mod.rs  |  4 +--
 4 files changed, 21 insertions(+), 26 deletions(-)

diff --git a/docs/book/content/types/scalars.md b/docs/book/content/types/scalars.md
index 857a1d020..a66468f41 100644
--- a/docs/book/content/types/scalars.md
+++ b/docs/book/content/types/scalars.md
@@ -131,8 +131,8 @@ where
     // NOTE: The error type should implement `IntoFieldError<S>`.
     fn from_input_value(v: &InputValue) -> Result<Date, String> {
         v.as_string_value()
-        .ok_or_else(|| format!("Expected String, found: {}", v))
-        .and_then(|s| s.parse().map_err(|e| format!("Failed to parse Date: {}", e)))
+        .ok_or_else(|| format!("Expected `String`, found: {}", v))
+        .and_then(|s| s.parse().map_err(|e| format!("Failed to parse `Date`: {}", e)))
     }
 
     // Define how to parse a string value.
diff --git a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
index facff5698..34d571903 100644
--- a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
+++ b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
@@ -1,7 +1,6 @@
 use juniper::{
     execute, graphql_object, graphql_scalar, graphql_value, graphql_vars, DefaultScalarValue,
-    EmptyMutation, EmptySubscription, FieldError, Object, ParseScalarResult, ParseScalarValue,
-    RootNode, Value,
+    EmptyMutation, EmptySubscription, Object, ParseScalarResult, ParseScalarValue, RootNode, Value,
 };
 
 use crate::custom_scalar::MyScalarValue;
@@ -32,10 +31,10 @@ where
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<DefaultName, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<DefaultName, String> {
         v.as_int_value()
             .map(DefaultName)
-            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -49,10 +48,10 @@ impl GraphQLScalar for OtherOrder {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<OtherOrder, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<OtherOrder, String> {
         v.as_int_value()
             .map(OtherOrder)
-            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -66,10 +65,10 @@ impl GraphQLScalar for Named {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<Named, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<Named, String> {
         v.as_int_value()
             .map(Named)
-            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -83,10 +82,10 @@ impl GraphQLScalar for ScalarDescription {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<ScalarDescription, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<ScalarDescription, String> {
         v.as_int_value()
             .map(ScalarDescription)
-            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -105,11 +104,11 @@ macro_rules! impl_scalar {
                 Value::scalar(self.0.clone())
             }
 
-            fn from_input_value(v: &InputValue) -> Result<Self, FieldError<S>> {
+            fn from_input_value(v: &InputValue) -> Result<Self, &'static str> {
                 v.as_scalar_value()
                     .and_then(|v| v.as_str())
                     .and_then(|s| Some(Self(s.to_owned())))
-                    .ok_or_else(|| "Expected String".into())
+                    .ok_or_else(|| "Expected `String`")
             }
 
             fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -148,9 +147,7 @@ impl GraphQLScalar for WithCustomScalarValue {
         Value::scalar(self.0)
     }
 
-    fn from_input_value(
-        v: &InputValue<MyScalarValue>,
-    ) -> Result<WithCustomScalarValue, FieldError<MyScalarValue>> {
+    fn from_input_value(v: &InputValue<MyScalarValue>) -> Result<WithCustomScalarValue, String> {
         v.as_int_value()
             .map(WithCustomScalarValue)
             .ok_or_else(|| format!("Expected Int, found: {}", v).into())
@@ -209,10 +206,10 @@ fn path_in_resolve_return_type() {
             Value::scalar(self.0)
         }
 
-        fn from_input_value(v: &InputValue) -> Result<ResolvePath, FieldError> {
+        fn from_input_value(v: &InputValue) -> Result<ResolvePath, String> {
             v.as_int_value()
                 .map(ResolvePath)
-                .ok_or_else(|| format!("Expected Int, found: {}", v).into())
+                .ok_or_else(|| format!("Expected Int, found: {}", v))
         }
 
         fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
diff --git a/integration_tests/juniper_tests/src/custom_scalar.rs b/integration_tests/juniper_tests/src/custom_scalar.rs
index 1ed488a6b..3e945934a 100644
--- a/integration_tests/juniper_tests/src/custom_scalar.rs
+++ b/integration_tests/juniper_tests/src/custom_scalar.rs
@@ -6,8 +6,8 @@ use juniper::{
     graphql_vars,
     parser::{ParseError, ScalarToken, Token},
     serde::{de, Deserialize, Deserializer, Serialize},
-    EmptyMutation, FieldError, FieldResult, GraphQLScalarValue, InputValue, Object,
-    ParseScalarResult, RootNode, ScalarValue, Value, Variables,
+    EmptyMutation, FieldResult, GraphQLScalarValue, InputValue, Object, ParseScalarResult,
+    RootNode, ScalarValue, Value, Variables,
 };
 
 #[derive(GraphQLScalarValue, Clone, Debug, PartialEq, Serialize)]
@@ -138,10 +138,10 @@ impl GraphQLScalar for i64 {
         Value::scalar(*self)
     }
 
-    fn from_input_value(v: &InputValue) -> Result<i64, FieldError> {
+    fn from_input_value(v: &InputValue) -> Result<i64, String> {
         v.as_scalar_value::<i64>()
             .copied()
-            .ok_or_else(|| format!("Expected MyScalarValue::Long(), found: {}", v).into())
+            .ok_or_else(|| format!("Expected MyScalarValue::Long(), found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, MyScalarValue> {
diff --git a/juniper_codegen/src/graphql_interface/mod.rs b/juniper_codegen/src/graphql_interface/mod.rs
index a509d3cf1..f6be46abf 100644
--- a/juniper_codegen/src/graphql_interface/mod.rs
+++ b/juniper_codegen/src/graphql_interface/mod.rs
@@ -884,9 +884,7 @@ impl Implementer {
                         return #resolving_code;
                     }
                 }
-                None => return Box::pin(::juniper::futures::future::ready(
-                    Err(::juniper::FieldError::from("This GraphQLType has no name"))
-                )),
+                None => return ::juniper::field_err_boxed_fut("This GraphQLType has no name"),
             }
         })
     }

From 982ec422eefb2f4adcb84cc6e9d20559e4d28124 Mon Sep 17 00:00:00 2001
From: ilslv <ilya.solovyiov@gmail.com>
Date: Tue, 14 Dec 2021 10:48:43 +0300
Subject: [PATCH 24/25] Corrections

---
 integration_tests/juniper_tests/src/codegen/impl_scalar.rs | 2 +-
 juniper/src/executor_tests/introspection/mod.rs            | 2 +-
 juniper/src/integrations/chrono_tz.rs                      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
index 34d571903..70a28a768 100644
--- a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
+++ b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
@@ -150,7 +150,7 @@ impl GraphQLScalar for WithCustomScalarValue {
     fn from_input_value(v: &InputValue<MyScalarValue>) -> Result<WithCustomScalarValue, String> {
         v.as_int_value()
             .map(WithCustomScalarValue)
-            .ok_or_else(|| format!("Expected Int, found: {}", v).into())
+            .ok_or_else(|| format!("Expected Int, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, MyScalarValue> {
diff --git a/juniper/src/executor_tests/introspection/mod.rs b/juniper/src/executor_tests/introspection/mod.rs
index c26baf1eb..07e7d668a 100644
--- a/juniper/src/executor_tests/introspection/mod.rs
+++ b/juniper/src/executor_tests/introspection/mod.rs
@@ -9,7 +9,7 @@ use crate::{
     graphql_interface, graphql_object, graphql_scalar, graphql_value, graphql_vars,
     schema::model::RootNode,
     types::scalars::{EmptyMutation, EmptySubscription},
-    value::{ParseScalarResult, ParseScalarValue, ScalarValue, Value},
+    value::{ParseScalarResult, ParseScalarValue, Value},
     GraphQLEnum,
 };
 
diff --git a/juniper/src/integrations/chrono_tz.rs b/juniper/src/integrations/chrono_tz.rs
index 8fce3a97b..dd84aa7a8 100644
--- a/juniper/src/integrations/chrono_tz.rs
+++ b/juniper/src/integrations/chrono_tz.rs
@@ -46,7 +46,7 @@ mod test {
 
         use chrono_tz::Tz;
 
-        use crate::{graphql_input_value, FieldError, FromInputValue, InputValue};
+        use crate::{graphql_input_value, FromInputValue, InputValue};
 
         fn tz_input_test(raw: &'static str, expected: Result<Tz, &str>) {
             let input: InputValue = graphql_input_value!((raw));

From afd607ef88ab7d59404397a5373355c6ddc8aec4 Mon Sep 17 00:00:00 2001
From: tyranron <tyranron@gmail.com>
Date: Tue, 14 Dec 2021 17:56:44 +0100
Subject: [PATCH 25/25] Polishing

---
 docs/book/content/types/scalars.md            |  6 +-
 integration_tests/async_await/src/main.rs     | 12 +--
 .../juniper_tests/src/codegen/impl_scalar.rs  | 10 +--
 .../juniper_tests/src/custom_scalar.rs        |  2 +-
 juniper/CHANGELOG.md                          |  2 +-
 juniper/src/executor/mod.rs                   |  9 ++
 .../introspection/input_object.rs             |  2 +-
 juniper/src/executor_tests/variables.rs       | 12 +--
 juniper/src/lib.rs                            |  6 +-
 juniper/src/macros/helper/mod.rs              | 45 +++++++---
 juniper/src/macros/mod.rs                     |  1 +
 juniper/src/validation/input_value.rs         |  3 +-
 juniper_codegen/src/common/field/arg.rs       | 83 +++++--------------
 juniper_codegen/src/common/field/mod.rs       | 30 +++----
 juniper_codegen/src/graphql_interface/mod.rs  | 18 ++--
 juniper_codegen/src/graphql_object/mod.rs     | 12 ++-
 .../src/graphql_subscription/mod.rs           |  6 +-
 juniper_codegen/src/graphql_union/mod.rs      | 14 ++--
 juniper_codegen/src/impl_scalar.rs            |  2 +-
 juniper_codegen/src/lib.rs                    |  2 +-
 juniper_codegen/src/util/mod.rs               |  4 +-
 21 files changed, 142 insertions(+), 139 deletions(-)

diff --git a/docs/book/content/types/scalars.md b/docs/book/content/types/scalars.md
index a66468f41..23afc7fd3 100644
--- a/docs/book/content/types/scalars.md
+++ b/docs/book/content/types/scalars.md
@@ -114,7 +114,7 @@ The example below is used just for illustration.
 #    }
 # }
 #
-use juniper::{FieldError, Value, ParseScalarResult, ParseScalarValue};
+use juniper::{Value, ParseScalarResult, ParseScalarValue};
 use date::Date;
 
 #[juniper::graphql_scalar(description = "Date")]
@@ -131,8 +131,8 @@ where
     // NOTE: The error type should implement `IntoFieldError<S>`.
     fn from_input_value(v: &InputValue) -> Result<Date, String> {
         v.as_string_value()
-        .ok_or_else(|| format!("Expected `String`, found: {}", v))
-        .and_then(|s| s.parse().map_err(|e| format!("Failed to parse `Date`: {}", e)))
+            .ok_or_else(|| format!("Expected `String`, found: {}", v))
+            .and_then(|s| s.parse().map_err(|e| format!("Failed to parse `Date`: {}", e)))
     }
 
     // Define how to parse a string value.
diff --git a/integration_tests/async_await/src/main.rs b/integration_tests/async_await/src/main.rs
index 076739446..2b913a7e9 100644
--- a/integration_tests/async_await/src/main.rs
+++ b/integration_tests/async_await/src/main.rs
@@ -81,8 +81,7 @@ mod tests {
     #[tokio::test]
     async fn async_simple() {
         let schema = RootNode::new(Query, EmptyMutation::new(), EmptySubscription::new());
-        let doc = r#"
-        query {
+        let doc = r#"query {
             fieldSync
             fieldAsyncPlain
             delayed
@@ -91,8 +90,7 @@ mod tests {
                 name
                 delayed
             }
-        }
-    "#;
+        }"#;
 
         let vars = Default::default();
         let (res, errs) = juniper::execute(doc, None, &schema, &vars, &())
@@ -122,8 +120,7 @@ mod tests {
     #[tokio::test]
     async fn async_field_validation_error() {
         let schema = RootNode::new(Query, EmptyMutation::new(), EmptySubscription::new());
-        let doc = r#"
-        query {
+        let doc = r#"query {
             nonExistentField
             fieldSync
             fieldAsyncPlain
@@ -133,8 +130,7 @@ mod tests {
                 name
                 delayed
             }
-        }
-    "#;
+        }"#;
 
         let vars = Default::default();
         let result = juniper::execute(doc, None, &schema, &vars, &()).await;
diff --git a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
index 70a28a768..1a53b8892 100644
--- a/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
+++ b/integration_tests/juniper_tests/src/codegen/impl_scalar.rs
@@ -34,7 +34,7 @@ where
     fn from_input_value(v: &InputValue) -> Result<DefaultName, String> {
         v.as_int_value()
             .map(DefaultName)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .ok_or_else(|| format!("Expected `Int`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -51,7 +51,7 @@ impl GraphQLScalar for OtherOrder {
     fn from_input_value(v: &InputValue) -> Result<OtherOrder, String> {
         v.as_int_value()
             .map(OtherOrder)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .ok_or_else(|| format!("Expected `Int`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -68,7 +68,7 @@ impl GraphQLScalar for Named {
     fn from_input_value(v: &InputValue) -> Result<Named, String> {
         v.as_int_value()
             .map(Named)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .ok_or_else(|| format!("Expected `Int`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -85,7 +85,7 @@ impl GraphQLScalar for ScalarDescription {
     fn from_input_value(v: &InputValue) -> Result<ScalarDescription, String> {
         v.as_int_value()
             .map(ScalarDescription)
-            .ok_or_else(|| format!("Expected Int, found: {}", v))
+            .ok_or_else(|| format!("Expected `Int`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
@@ -209,7 +209,7 @@ fn path_in_resolve_return_type() {
         fn from_input_value(v: &InputValue) -> Result<ResolvePath, String> {
             v.as_int_value()
                 .map(ResolvePath)
-                .ok_or_else(|| format!("Expected Int, found: {}", v))
+                .ok_or_else(|| format!("Expected `Int`, found: {}", v))
         }
 
         fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, DefaultScalarValue> {
diff --git a/integration_tests/juniper_tests/src/custom_scalar.rs b/integration_tests/juniper_tests/src/custom_scalar.rs
index 3e945934a..a59b73002 100644
--- a/integration_tests/juniper_tests/src/custom_scalar.rs
+++ b/integration_tests/juniper_tests/src/custom_scalar.rs
@@ -141,7 +141,7 @@ impl GraphQLScalar for i64 {
     fn from_input_value(v: &InputValue) -> Result<i64, String> {
         v.as_scalar_value::<i64>()
             .copied()
-            .ok_or_else(|| format!("Expected MyScalarValue::Long(), found: {}", v))
+            .ok_or_else(|| format!("Expected `MyScalarValue::Long`, found: {}", v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, MyScalarValue> {
diff --git a/juniper/CHANGELOG.md b/juniper/CHANGELOG.md
index a67d370a1..88e58f9f7 100644
--- a/juniper/CHANGELOG.md
+++ b/juniper/CHANGELOG.md
@@ -8,7 +8,7 @@
 - `rename = "<policy>"` attribute's argument renamed to `rename_all = "<policy>"`. ([#971](https://github.com/graphql-rust/juniper/pull/971))
 - Upgrade `bson` feature to [2.0 version of its crate](https://github.com/mongodb/bson-rust/releases/tag/v2.0.0). ([#979](https://github.com/graphql-rust/juniper/pull/979))
 - Make `FromInputValue` methods fallible to allow post-validation. ([#987](https://github.com/graphql-rust/juniper/pull/987))
-- Change `Option` to `Result` in `#[graphql_scalar]` macro in `from_input_value()` return type. ([#987](https://github.com/graphql-rust/juniper/pull/987))
+- Change `Option` to `Result` in `from_input_value()` return type of `#[graphql_scalar]` macro. ([#987](https://github.com/graphql-rust/juniper/pull/987))
 - Forbid `__typename` field on `subscription` operations [accordingly to October 2021 spec](https://spec.graphql.org/October2021/#note-bc213). ([#1001](https://github.com/graphql-rust/juniper/pull/1001), [#1000](https://github.com/graphql-rust/juniper/pull/1000))
 
 ## Features
diff --git a/juniper/src/executor/mod.rs b/juniper/src/executor/mod.rs
index 5a8cf32c7..553af48ea 100644
--- a/juniper/src/executor/mod.rs
+++ b/juniper/src/executor/mod.rs
@@ -230,6 +230,15 @@ impl<S> FieldError<S> {
             extensions: self.extensions.map_scalar_value(),
         }
     }
+
+    /// Maps the [`FieldError::message`] with the given function.
+    #[must_use]
+    pub fn map_message(self, f: impl FnOnce(String) -> String) -> Self {
+        Self {
+            message: f(self.message),
+            extensions: self.extensions,
+        }
+    }
 }
 
 /// The result of resolving the value of a field of type `T`
diff --git a/juniper/src/executor_tests/introspection/input_object.rs b/juniper/src/executor_tests/introspection/input_object.rs
index d433681a5..f68b97963 100644
--- a/juniper/src/executor_tests/introspection/input_object.rs
+++ b/juniper/src/executor_tests/introspection/input_object.rs
@@ -206,7 +206,7 @@ fn default_name_input_value() {
 
     let dv = DefaultName::from_input_value(&iv);
 
-    assert!(dv.is_ok(), "error: {:?}", dv.unwrap_err());
+    assert!(dv.is_ok(), "error: {}", dv.unwrap_err().message());
 
     let dv = dv.unwrap();
 
diff --git a/juniper/src/executor_tests/variables.rs b/juniper/src/executor_tests/variables.rs
index 6af5ef7f5..d05727307 100644
--- a/juniper/src/executor_tests/variables.rs
+++ b/juniper/src/executor_tests/variables.rs
@@ -23,7 +23,7 @@ impl<S: ScalarValue> GraphQLScalar for TestComplexScalar {
         v.as_string_value()
             .filter(|s| *s == "SerializedValue")
             .map(|_| TestComplexScalar)
-            .ok_or_else(|| format!("Expected SerializedValue String, found: {}", v))
+            .ok_or_else(|| format!(r#"Expected "SerializedValue" string, found: {}"#, v))
     }
 
     fn from_str<'a>(value: ScalarToken<'a>) -> ParseScalarResult<'a, S> {
@@ -1097,8 +1097,9 @@ mod integers {
         assert_eq!(
             error,
             ValidationError(vec![RuleError::new(
-                "Variable \"$var\" got invalid value. Expected input scalar `Int`. \
-                 Got: `\"10\"`. Details: Expected `Int`, found: \"10\".",
+                "Variable \"$var\" got invalid value. \
+                 Expected input scalar `Int`. Got: `\"10\"`. \
+                 Details: Expected `Int`, found: \"10\".",
                 &[SourcePosition::new(8, 0, 8)],
             )]),
         );
@@ -1156,8 +1157,9 @@ mod floats {
         assert_eq!(
             error,
             ValidationError(vec![RuleError::new(
-                "Variable \"$var\" got invalid value. Expected input scalar `Float`. \
-                 Got: `\"10\"`. Details: Expected `Float`, found: \"10\".",
+                "Variable \"$var\" got invalid value. \
+                 Expected input scalar `Float`. Got: `\"10\"`. \
+                 Details: Expected `Float`, found: \"10\".",
                 &[SourcePosition::new(8, 0, 8)],
             )]),
         );
diff --git a/juniper/src/lib.rs b/juniper/src/lib.rs
index c63931d68..a986d540b 100644
--- a/juniper/src/lib.rs
+++ b/juniper/src/lib.rs
@@ -116,8 +116,9 @@ pub use juniper_codegen::{
     GraphQLEnum, GraphQLInputObject, GraphQLObject, GraphQLScalarValue, GraphQLUnion,
 };
 
+#[doc(hidden)]
 #[macro_use]
-mod macros;
+pub mod macros;
 mod ast;
 pub mod executor;
 mod introspection;
@@ -162,9 +163,8 @@ pub use crate::{
     },
     introspection::IntrospectionFormat,
     macros::helper::{
-        field_err_boxed_fut,
         subscription::{ExtractTypeFromStream, IntoFieldResult},
-        AsDynGraphQLValue, ExtractError,
+        AsDynGraphQLValue,
     },
     parser::{ParseError, Spanning},
     schema::{
diff --git a/juniper/src/macros/helper/mod.rs b/juniper/src/macros/helper/mod.rs
index 2715ff140..0f81018da 100644
--- a/juniper/src/macros/helper/mod.rs
+++ b/juniper/src/macros/helper/mod.rs
@@ -2,24 +2,12 @@
 
 pub mod subscription;
 
-use std::fmt::Display;
+use std::fmt;
 
 use futures::future::{self, BoxFuture};
 
 use crate::{DefaultScalarValue, DynGraphQLValue, DynGraphQLValueAsync, FieldError, ScalarValue};
 
-/// Wraps `msg` with [`Display`] implementation into opaque [`Send`] [`Future`]
-/// which immediately resolves into [`FieldError`].
-#[doc(hidden)]
-pub fn field_err_boxed_fut<'ok, D, Ok, S>(msg: D) -> BoxFuture<'ok, Result<Ok, FieldError<S>>>
-where
-    D: Display,
-    Ok: Send + 'ok,
-    S: Send + 'static,
-{
-    Box::pin(future::err(FieldError::from(msg)))
-}
-
 /// Conversion of a [`GraphQLValue`] to its [trait object][1].
 ///
 /// [`GraphQLValue`]: crate::GraphQLValue
@@ -64,3 +52,34 @@ pub trait ExtractError {
 impl<T, E> ExtractError for Result<T, E> {
     type Error = E;
 }
+
+/// Wraps `msg` with [`Display`] implementation into opaque [`Send`] [`Future`]
+/// which immediately resolves into [`FieldError`].
+pub fn err_fut<'ok, D, Ok, S>(msg: D) -> BoxFuture<'ok, Result<Ok, FieldError<S>>>
+where
+    D: fmt::Display,
+    Ok: Send + 'ok,
+    S: Send + 'static,
+{
+    Box::pin(future::err(FieldError::from(msg)))
+}
+
+/// Generates a [`FieldError`] for the given Rust type expecting to have
+/// [`GraphQLType::name`].
+///
+/// [`GraphQLType::name`]: crate::GraphQLType::name
+pub fn err_unnamed_type<S>(name: &str) -> FieldError<S> {
+    FieldError::from(format!(
+        "Expected `{}` type to implement `GraphQLType::name`",
+        name,
+    ))
+}
+
+/// Returns a [`future::err`] wrapping the [`err_unnamed_type`].
+pub fn err_unnamed_type_fut<'ok, Ok, S>(name: &str) -> BoxFuture<'ok, Result<Ok, FieldError<S>>>
+where
+    Ok: Send + 'ok,
+    S: Send + 'static,
+{
+    Box::pin(future::err(err_unnamed_type(name)))
+}
diff --git a/juniper/src/macros/mod.rs b/juniper/src/macros/mod.rs
index 273ee814e..cecfee388 100644
--- a/juniper/src/macros/mod.rs
+++ b/juniper/src/macros/mod.rs
@@ -1,5 +1,6 @@
 //! Declarative macros and helper definitions for procedural macros.
 
+#[doc(hidden)]
 pub mod helper;
 
 #[macro_use]
diff --git a/juniper/src/validation/input_value.rs b/juniper/src/validation/input_value.rs
index 95f5d1350..b62381722 100644
--- a/juniper/src/validation/input_value.rs
+++ b/juniper/src/validation/input_value.rs
@@ -169,7 +169,8 @@ where
                                 var_pos,
                                 &path,
                                 &format!(
-                                    "Expected input of type `{}`. Got: `{}`. Details: {}",
+                                    "Expected input of type `{}`. Got: `{}`. \
+                                     Details: {}",
                                     iom.name,
                                     value,
                                     e.message(),
diff --git a/juniper_codegen/src/common/field/arg.rs b/juniper_codegen/src/common/field/arg.rs
index 274f93532..0534432c2 100644
--- a/juniper_codegen/src/common/field/arg.rs
+++ b/juniper_codegen/src/common/field/arg.rs
@@ -347,73 +347,34 @@ impl OnMethod {
     ///
     /// [`GraphQLValue::resolve_field`]: juniper::GraphQLValue::resolve_field
     #[must_use]
-    pub(crate) fn method_resolve_field_tokens(&self, scalar: &scalar::Type) -> TokenStream {
+    pub(crate) fn method_resolve_field_tokens(
+        &self,
+        scalar: &scalar::Type,
+        for_async: bool,
+    ) -> TokenStream {
         match self {
             Self::Regular(arg) => {
                 let (name, ty) = (&arg.name, &arg.ty);
                 let err_text = format!("Missing argument `{}`: {{}}", &name);
-                quote! {
-                    args.get::<#ty>(#name)
-                        .and_then(|opt| {
-                            opt.map_or_else(
-                                || {
-                                    <#ty as ::juniper::FromInputValue<#scalar>>::
-                                        from_implicit_null()
-                                        .map_err(|e| {
-                                            let e = ::juniper::IntoFieldError::into_field_error(e);
-                                            ::juniper::FieldError::new(
-                                                format!(#err_text, e.message()),
-                                                e.extensions().clone(),
-                                            )
-                                        })
-                                },
-                                Ok,
-                            )
-                        })?
-                }
-            }
-
-            Self::Context(_) => quote! {
-                ::juniper::FromContext::from(executor.context())
-            },
-
-            Self::Executor => quote! { &executor },
-        }
-    }
 
-    /// Returns generated code for the [`GraphQLValue::resolve_field`] method,
-    /// which provides the value of this [`OnMethod`] argument to be passed into
-    /// a trait method call.
-    ///
-    /// [`GraphQLValue::resolve_field`]: juniper::GraphQLValue::resolve_field
-    #[must_use]
-    pub(crate) fn method_resolve_field_async_tokens(&self, scalar: &scalar::Type) -> TokenStream {
-        match self {
-            Self::Regular(arg) => {
-                let (name, ty) = (&arg.name, &arg.ty);
-                let err_text = format!("Missing argument `{}`: {{}}", &name);
-                quote! {
-                    match args.get::<#ty>(#name)
-                        .and_then(|opt| {
-                            opt.map_or_else(
-                                || {
-                                    <#ty as ::juniper::FromInputValue<#scalar>>::
-                                        from_implicit_null()
-                                        .map_err(|e| {
-                                            let e = ::juniper::IntoFieldError::into_field_error(e);
-                                            ::juniper::FieldError::new(
-                                                format!(#err_text, e.message()),
-                                                e.extensions().clone(),
-                                            )
-                                        })
-                                },
-                                Ok,
-                            )
-                        })
-                    {
-                        Ok(ok) => ok,
-                        Err(err) => return Box::pin(async { Err(err) }),
+                let arg = quote! {
+                    args.get::<#ty>(#name).and_then(|opt| opt.map_or_else(|| {
+                        <#ty as ::juniper::FromInputValue<#scalar>>::from_implicit_null()
+                            .map_err(|e| {
+                                ::juniper::IntoFieldError::<#scalar>::into_field_error(e)
+                                    .map_message(|m| format!(#err_text, m))
+                            })
+                    }, Ok))
+                };
+                if for_async {
+                    quote! {
+                        match #arg {
+                            Ok(v) => v,
+                            Err(e) => return Box::pin(async { Err(e) }),
+                        }
                     }
+                } else {
+                    quote! { #arg? }
                 }
             }
 
diff --git a/juniper_codegen/src/common/field/mod.rs b/juniper_codegen/src/common/field/mod.rs
index fbf442ced..0437f97f3 100644
--- a/juniper_codegen/src/common/field/mod.rs
+++ b/juniper_codegen/src/common/field/mod.rs
@@ -274,13 +274,16 @@ impl Definition {
     /// [`GraphQLValue::resolve_field`]: juniper::GraphQLValue::resolve_field
     /// [1]: https://spec.graphql.org/June2018/#sec-Language.Fields
     #[must_use]
-    pub(crate) fn method_resolve_field_err_no_field_tokens(scalar: &scalar::Type) -> TokenStream {
+    pub(crate) fn method_resolve_field_err_no_field_tokens(
+        scalar: &scalar::Type,
+        ty_name: &str,
+    ) -> TokenStream {
         quote! {
-            return Err(::juniper::FieldError::<#scalar>::from(format!(
+            return Err(::juniper::FieldError::from(format!(
                 "Field `{}` not found on type `{}`",
                 field,
                 <Self as ::juniper::GraphQLType<#scalar>>::name(info)
-                    .ok_or_else(|| ::juniper::FieldError::<#scalar>::from("No name for GraphQLType"))?,
+                    .ok_or_else(|| ::juniper::macros::helper::err_unnamed_type(#ty_name))?,
             )))
         }
     }
@@ -295,16 +298,15 @@ impl Definition {
     pub(crate) fn method_resolve_field_err_async_field_tokens(
         field_names: &[&str],
         scalar: &scalar::Type,
+        ty_name: &str,
     ) -> TokenStream {
         quote! {
-            #( #field_names )|* => return Err(::juniper::FieldError::<#scalar>::from(
-                format!(
-                    "Tried to resolve async field `{}` on type `{}` with a sync resolver",
-                    field,
-                    <Self as ::juniper::GraphQLType<#scalar>>::name(info)
-                        .ok_or_else(|| ::juniper::FieldError::<#scalar>::from("No name for GraphQLType"))?,
-                )
-            )),
+            #( #field_names )|* => return Err(::juniper::FieldError::from(format!(
+                "Tried to resolve async field `{}` on type `{}` with a sync resolver",
+                field,
+                <Self as ::juniper::GraphQLType<#scalar>>::name(info)
+                    .ok_or_else(|| ::juniper::macros::helper::err_unnamed_type(#ty_name))?,
+            ))),
         }
     }
 
@@ -413,7 +415,7 @@ impl Definition {
                 .as_ref()
                 .unwrap()
                 .iter()
-                .map(|arg| arg.method_resolve_field_tokens(scalar));
+                .map(|arg| arg.method_resolve_field_tokens(scalar, false));
 
             let rcv = self.has_receiver.then(|| {
                 quote! { self, }
@@ -459,7 +461,7 @@ impl Definition {
                 .as_ref()
                 .unwrap()
                 .iter()
-                .map(|arg| arg.method_resolve_field_async_tokens(scalar));
+                .map(|arg| arg.method_resolve_field_tokens(scalar, true));
 
             let rcv = self.has_receiver.then(|| {
                 quote! { self, }
@@ -508,7 +510,7 @@ impl Definition {
                 .as_ref()
                 .unwrap()
                 .iter()
-                .map(|arg| arg.method_resolve_field_tokens(scalar));
+                .map(|arg| arg.method_resolve_field_tokens(scalar, false));
 
             let rcv = self.has_receiver.then(|| {
                 quote! { self, }
diff --git a/juniper_codegen/src/graphql_interface/mod.rs b/juniper_codegen/src/graphql_interface/mod.rs
index f6be46abf..0e4ff0665 100644
--- a/juniper_codegen/src/graphql_interface/mod.rs
+++ b/juniper_codegen/src/graphql_interface/mod.rs
@@ -572,6 +572,7 @@ impl Definition {
 
         let (impl_generics, where_clause) = self.ty.impl_generics(false);
         let ty = self.ty.ty_tokens();
+        let ty_name = ty.to_string();
         let trait_ty = self.ty.trait_ty();
 
         let fields_resolvers = self
@@ -585,10 +586,13 @@ impl Definition {
                 .filter_map(|f| f.is_async.then(|| f.name.as_str()))
                 .collect::<Vec<_>>();
             (!names.is_empty()).then(|| {
-                field::Definition::method_resolve_field_err_async_field_tokens(&names, scalar)
+                field::Definition::method_resolve_field_err_async_field_tokens(
+                    &names, scalar, &ty_name,
+                )
             })
         };
-        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
+        let no_field_err =
+            field::Definition::method_resolve_field_err_no_field_tokens(scalar, &ty_name);
 
         let custom_downcast_checks = self
             .implementers
@@ -662,13 +666,15 @@ impl Definition {
 
         let (impl_generics, where_clause) = self.ty.impl_generics(true);
         let ty = self.ty.ty_tokens();
+        let ty_name = ty.to_string();
         let trait_ty = self.ty.trait_ty();
 
         let fields_resolvers = self
             .fields
             .iter()
             .map(|f| f.method_resolve_field_async_tokens(scalar, Some(&trait_ty)));
-        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
+        let no_field_err =
+            field::Definition::method_resolve_field_err_no_field_tokens(scalar, &ty_name);
 
         let custom_downcasts = self
             .implementers
@@ -840,6 +846,7 @@ impl Implementer {
         self.downcast.as_ref()?;
 
         let ty = &self.ty;
+        let ty_name = ty.to_token_stream().to_string();
         let scalar = &self.scalar;
 
         let downcast = self.downcast_call_tokens(trait_ty, None);
@@ -848,7 +855,7 @@ impl Implementer {
 
         Some(quote! {
             if type_name == <#ty as ::juniper::GraphQLType<#scalar>>::name(info)
-                .ok_or_else(|| ::juniper::FieldError::from("This GraphQLType has no name"))?
+                .ok_or_else(|| ::juniper::macros::helper::err_unnamed_type(#ty_name))?
             {
                 let res = #downcast;
                 return #resolving_code;
@@ -870,6 +877,7 @@ impl Implementer {
         self.downcast.as_ref()?;
 
         let ty = &self.ty;
+        let ty_name = ty.to_token_stream().to_string();
         let scalar = &self.scalar;
 
         let downcast = self.downcast_call_tokens(trait_ty, None);
@@ -884,7 +892,7 @@ impl Implementer {
                         return #resolving_code;
                     }
                 }
-                None => return ::juniper::field_err_boxed_fut("This GraphQLType has no name"),
+                None => return ::juniper::macros::helper::err_unnamed_type_fut(#ty_name),
             }
         })
     }
diff --git a/juniper_codegen/src/graphql_object/mod.rs b/juniper_codegen/src/graphql_object/mod.rs
index dd9a1b3a6..171e00a3d 100644
--- a/juniper_codegen/src/graphql_object/mod.rs
+++ b/juniper_codegen/src/graphql_object/mod.rs
@@ -486,6 +486,7 @@ impl Definition<Query> {
 
         let (impl_generics, where_clause) = self.impl_generics(false);
         let ty = &self.ty;
+        let ty_name = ty.to_token_stream().to_string();
 
         let name = &self.name;
 
@@ -500,10 +501,13 @@ impl Definition<Query> {
                 .filter_map(|f| f.is_async.then(|| f.name.as_str()))
                 .collect::<Vec<_>>();
             (!names.is_empty()).then(|| {
-                field::Definition::method_resolve_field_err_async_field_tokens(&names, scalar)
+                field::Definition::method_resolve_field_err_async_field_tokens(
+                    &names, scalar, &ty_name,
+                )
             })
         };
-        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
+        let no_field_err =
+            field::Definition::method_resolve_field_err_no_field_tokens(scalar, &ty_name);
 
         quote! {
             #[allow(deprecated)]
@@ -553,12 +557,14 @@ impl Definition<Query> {
 
         let (impl_generics, where_clause) = self.impl_generics(true);
         let ty = &self.ty;
+        let ty_name = ty.to_token_stream().to_string();
 
         let fields_resolvers = self
             .fields
             .iter()
             .map(|f| f.method_resolve_field_async_tokens(scalar, None));
-        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
+        let no_field_err =
+            field::Definition::method_resolve_field_err_no_field_tokens(scalar, &ty_name);
 
         quote! {
             #[allow(deprecated, non_snake_case)]
diff --git a/juniper_codegen/src/graphql_subscription/mod.rs b/juniper_codegen/src/graphql_subscription/mod.rs
index 288547485..ca64e0e0b 100644
--- a/juniper_codegen/src/graphql_subscription/mod.rs
+++ b/juniper_codegen/src/graphql_subscription/mod.rs
@@ -61,7 +61,7 @@ impl Definition<Subscription> {
                     _: &::juniper::Executor<Self::Context, #scalar>,
                 ) -> ::juniper::ExecutionResult<#scalar> {
                     Err(::juniper::FieldError::from(
-                        "Called `resolve_field` on subscription object"
+                        "Called `resolve_field` on subscription object",
                     ))
                 }
 
@@ -97,12 +97,14 @@ impl Definition<Subscription> {
                 .push(parse_quote! { #scalar: Send + Sync });
         }
         let ty = &self.ty;
+        let ty_name = ty.to_token_stream().to_string();
 
         let fields_resolvers = self
             .fields
             .iter()
             .map(|f| f.method_resolve_field_into_stream_tokens(scalar));
-        let no_field_err = field::Definition::method_resolve_field_err_no_field_tokens(scalar);
+        let no_field_err =
+            field::Definition::method_resolve_field_err_no_field_tokens(scalar, &ty_name);
 
         quote! {
             #[allow(deprecated)]
diff --git a/juniper_codegen/src/graphql_union/mod.rs b/juniper_codegen/src/graphql_union/mod.rs
index 9d2ae57fb..00ba528e5 100644
--- a/juniper_codegen/src/graphql_union/mod.rs
+++ b/juniper_codegen/src/graphql_union/mod.rs
@@ -558,7 +558,6 @@ impl Definition {
                 ) -> ::juniper::ExecutionResult<#scalar> {
                     let context = executor.context();
                     #( #variant_resolvers )*
-
                     return Err(::juniper::FieldError::from(format!(
                         "Concrete type `{}` is not handled by instance \
                          resolvers on GraphQL union `{}`",
@@ -601,10 +600,9 @@ impl Definition {
                 ) -> ::juniper::BoxFuture<'b, ::juniper::ExecutionResult<#scalar>> {
                     let context = executor.context();
                     #( #variant_async_resolvers )*
-
-                    return ::juniper::field_err_boxed_fut(format!(
+                    return ::juniper::macros::helper::err_fut(format!(
                         "Concrete type `{}` is not handled by instance \
-                        resolvers on GraphQL union `{}`",
+                         resolvers on GraphQL union `{}`",
                         type_name, #name,
                     ));
                 }
@@ -672,12 +670,13 @@ impl VariantDefinition {
     #[must_use]
     fn method_resolve_into_type_tokens(&self, scalar: &scalar::Type) -> TokenStream {
         let ty = &self.ty;
+        let ty_name = ty.to_token_stream().to_string();
         let expr = &self.resolver_code;
         let resolving_code = gen::sync_resolving_code();
 
         quote! {
             if type_name == <#ty as ::juniper::GraphQLType<#scalar>>::name(info)
-                .ok_or_else(|| ::juniper::FieldError::from("This GraphQLType has no name"))?
+                .ok_or_else(|| ::juniper::macros::helper::err_unnamed_type(#ty_name))?
             {
                 let res = { #expr };
                 return #resolving_code;
@@ -694,6 +693,7 @@ impl VariantDefinition {
     #[must_use]
     fn method_resolve_into_type_async_tokens(&self, scalar: &scalar::Type) -> TokenStream {
         let ty = &self.ty;
+        let ty_name = ty.to_token_stream().to_string();
         let expr = &self.resolver_code;
         let resolving_code = gen::async_resolving_code(None);
 
@@ -705,9 +705,7 @@ impl VariantDefinition {
                         return #resolving_code;
                     }
                 }
-                None => return ::juniper::field_err_boxed_fut(
-                    "This GraphQLType has no name"
-                ),
+                None => return ::juniper::macros::helper::err_unnamed_type_fut(#ty_name),
             }
         }
     }
diff --git a/juniper_codegen/src/impl_scalar.rs b/juniper_codegen/src/impl_scalar.rs
index 7bf901c63..94c8481c3 100644
--- a/juniper_codegen/src/impl_scalar.rs
+++ b/juniper_codegen/src/impl_scalar.rs
@@ -309,7 +309,7 @@ pub fn build_scalar(
         impl#generic_type_decl ::juniper::FromInputValue<#generic_type> for #impl_for_type
         #generic_type_bound
         {
-            type Error = <#from_input_value_result as ::juniper::ExtractError>::Error;
+            type Error = <#from_input_value_result as ::juniper::macros::helper::ExtractError>::Error;
 
             fn from_input_value(#from_input_value_arg: &::juniper::InputValue<#generic_type>) -> #from_input_value_result {
                 #from_input_value_body
diff --git a/juniper_codegen/src/lib.rs b/juniper_codegen/src/lib.rs
index b25967a6e..14f4c1a79 100644
--- a/juniper_codegen/src/lib.rs
+++ b/juniper_codegen/src/lib.rs
@@ -234,7 +234,7 @@ pub fn derive_scalar_value(input: TokenStream) -> TokenStream {
 ///     fn from_input_value(value: &juniper::InputValue) -> Result<UserID, String> {
 ///         value.as_string_value()
 ///             .map(|s| UserID(s.to_owned()))
-///             .ok_or_else(|| format!("Expected String, found: {}", value))
+///             .ok_or_else(|| format!("Expected `String`, found: {}", value))
 ///     }
 ///
 ///     fn from_str<'a>(value: juniper::ScalarToken<'a>) -> juniper::ParseScalarResult<'a, S> {
diff --git a/juniper_codegen/src/util/mod.rs b/juniper_codegen/src/util/mod.rs
index a6083e073..d8002f512 100644
--- a/juniper_codegen/src/util/mod.rs
+++ b/juniper_codegen/src/util/mod.rs
@@ -865,9 +865,7 @@ impl GraphQLTypeDefiniton {
                 fn from_input_value(
                     v: &::juniper::InputValue<#scalar>
                 ) -> Result<#ty, Self::Error> {
-                    match v.as_enum_value().or_else(|| {
-                        v.as_string_value()
-                    }) {
+                    match v.as_enum_value().or_else(|| v.as_string_value()) {
                         #( #from_inputs )*
                         _ => Err(format!("Unknown enum value: {}", v)),
                     }