internal: Improve macro token mapping heuristics

Cargo.toml

@@ -184,6 +184,8 @@ style = { level = "warn", priority = -1 }
 suspicious = { level = "warn", priority = -1 }
 
 ## allow following lints
+# subjective
+single_match = "allow"
 # () makes a fine error in most cases
 result_unit_err = "allow"
 # We don't expose public APIs that matter like this

crates/hir-expand/src/files.rs

@@ -461,3 +461,12 @@ impl<N: AstNode> InFile<N> {
         Some(InRealFile::new(file_id, value))
     }
 }
+
+impl<T> InFile<T> {
+    pub fn into_real_file(self) -> Result<InRealFile<T>, InFile<T>> {
+        match self.file_id.repr() {
+            HirFileIdRepr::FileId(file_id) => Ok(InRealFile { file_id, value: self.value }),
+            HirFileIdRepr::MacroFile(_) => Err(self),
+        }
+    }
+}

crates/hir-expand/src/lib.rs

@@ -279,6 +279,7 @@ pub enum MacroCallKind {
 }
 
 pub trait HirFileIdExt {
+    fn edition(self, db: &dyn ExpandDatabase) -> Edition;
     /// Returns the original file of this macro call hierarchy.
     fn original_file(self, db: &dyn ExpandDatabase) -> EditionedFileId;
 
@@ -293,6 +294,12 @@ pub trait HirFileIdExt {
 }
 
 impl HirFileIdExt for HirFileId {
+    fn edition(self, db: &dyn ExpandDatabase) -> Edition {
+        match self.repr() {
+            HirFileIdRepr::FileId(file_id) => file_id.edition(),
+            HirFileIdRepr::MacroFile(m) => m.macro_call_id.lookup(db).def.edition,
+        }
+    }
     fn original_file(self, db: &dyn ExpandDatabase) -> EditionedFileId {
         let mut file_id = self;
         loop {

crates/hir/src/lib.rs

@@ -93,8 +93,7 @@ pub use crate::{
     diagnostics::*,
     has_source::HasSource,
     semantics::{
-        DescendPreference, PathResolution, Semantics, SemanticsImpl, SemanticsScope, TypeInfo,
-        VisibleTraits,
+        PathResolution, Semantics, SemanticsImpl, SemanticsScope, TypeInfo, VisibleTraits,
     },
 };
 pub use hir_ty::method_resolution::TyFingerprint;