Skip to content

Reword needless_question_mark diagnostics and docs #14682

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Apr 23, 2025
Merged

Reword needless_question_mark diagnostics and docs #14682

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
70 changes: 33 additions & 37 deletions clippy_lints/src/needless_question_mark.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,6 +1,5 @@
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::diagnostics::span_lint_hir_and_then;
use clippy_utils::path_res;
use clippy_utils::source::snippet;
use rustc_errors::Applicability;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::{Block, Body, Expr, ExprKind, LangItem, MatchSource, QPath};
Expand All @@ -9,52 +8,38 @@ use rustc_session::declare_lint_pass;

declare_clippy_lint! {
/// ### What it does
/// Suggests alternatives for useless applications of `?` in terminating expressions
/// Suggests replacing `Ok(x?)` or `Some(x?)` with `x` in return positions where the `?` operator
/// is not needed to convert the type of `x`.
///
/// ### Why is this bad?
/// There's no reason to use `?` to short-circuit when execution of the body will end there anyway.
///
/// ### Example
/// ```no_run
/// struct TO {
/// magic: Option<usize>,
/// # use std::num::ParseIntError;
/// fn f(s: &str) -> Option<usize> {
/// Some(s.find('x')?)
/// }
///
/// fn f(to: TO) -> Option<usize> {
/// Some(to.magic?)
/// fn g(s: &str) -> Result<usize, ParseIntError> {
/// Ok(s.parse()?)
/// }
///
/// struct TR {
/// magic: Result<usize, bool>,
/// }
///
/// fn g(tr: Result<TR, bool>) -> Result<usize, bool> {
/// tr.and_then(|t| Ok(t.magic?))
/// }
///
/// ```
/// Use instead:
/// ```no_run
/// struct TO {
/// magic: Option<usize>,
/// # use std::num::ParseIntError;
/// fn f(s: &str) -> Option<usize> {
/// s.find('x')
/// }
///
/// fn f(to: TO) -> Option<usize> {
/// to.magic
/// }
///
/// struct TR {
/// magic: Result<usize, bool>,
/// }
///
/// fn g(tr: Result<TR, bool>) -> Result<usize, bool> {
/// tr.and_then(|t| t.magic)
/// fn g(s: &str) -> Result<usize, ParseIntError> {
/// s.parse()
/// }
/// ```
#[clippy::version = "1.51.0"]
pub NEEDLESS_QUESTION_MARK,
complexity,
"Suggest `value.inner_option` instead of `Some(value.inner_option?)`. The same goes for `Result<T, E>`."
"using `Ok(x?)` or `Some(x?)` where `x` would be equivalent"
}

declare_lint_pass!(NeedlessQuestionMark => [NEEDLESS_QUESTION_MARK]);
Expand Down Expand Up @@ -111,10 +96,10 @@ fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
if let ExprKind::Call(path, [arg]) = expr.kind
&& let Res::Def(DefKind::Ctor(..), ctor_id) = path_res(cx, path)
&& let Some(variant_id) = cx.tcx.opt_parent(ctor_id)
&& let sugg_remove = if cx.tcx.lang_items().option_some_variant() == Some(variant_id) {
"Some()"
&& let variant = if cx.tcx.lang_items().option_some_variant() == Some(variant_id) {
"Some"
} else if cx.tcx.lang_items().result_ok_variant() == Some(variant_id) {
"Ok()"
"Ok"
} else {
return;
}
Expand All @@ -126,14 +111,25 @@ fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
&& let inner_ty = cx.typeck_results().expr_ty(inner_expr)
&& expr_ty == inner_ty
{
span_lint_and_sugg(
span_lint_hir_and_then(
cx,
NEEDLESS_QUESTION_MARK,
expr.hir_id,
expr.span,
"question mark operator is useless here",
format!("try removing question mark and `{sugg_remove}`"),
format!("{}", snippet(cx, inner_expr.span, r#""...""#)),
Applicability::MachineApplicable,
format!("enclosing `{variant}` and `?` operator are unneeded"),
|diag| {
diag.multipart_suggestion(
format!("remove the enclosing `{variant}` and `?` operator"),
vec![
(expr.span.until(inner_expr.span), String::new()),
(
inner_expr.span.shrink_to_hi().to(expr.span.shrink_to_hi()),
String::new(),
),
],
Applicability::MachineApplicable,
);
},
);
}
}
148 changes: 118 additions & 30 deletions tests/ui/needless_question_mark.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,100 +1,188 @@
error: question mark operator is useless here
error: enclosing `Some` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:20:12
|
LL | return Some(to.magic?);
| ^^^^^^^^^^^^^^^ help: try removing question mark and `Some()`: `to.magic`
| ^^^^^^^^^^^^^^^
|
= note: `-D clippy::needless-question-mark` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::needless_question_mark)]`
help: remove the enclosing `Some` and `?` operator
|
LL - return Some(to.magic?);
LL + return to.magic;
|

error: question mark operator is useless here
error: enclosing `Some` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:29:12
|
LL | return Some(to.magic?)
| ^^^^^^^^^^^^^^^ help: try removing question mark and `Some()`: `to.magic`
| ^^^^^^^^^^^^^^^
|
help: remove the enclosing `Some` and `?` operator
|
LL - return Some(to.magic?)
LL + return to.magic
|

error: question mark operator is useless here
error: enclosing `Some` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:35:5
|
LL | Some(to.magic?)
| ^^^^^^^^^^^^^^^ help: try removing question mark and `Some()`: `to.magic`
| ^^^^^^^^^^^^^^^
|
help: remove the enclosing `Some` and `?` operator
|
LL - Some(to.magic?)
LL + to.magic
|

error: question mark operator is useless here
error: enclosing `Some` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:41:21
|
LL | to.and_then(|t| Some(t.magic?))
| ^^^^^^^^^^^^^^ help: try removing question mark and `Some()`: `t.magic`
| ^^^^^^^^^^^^^^
|
help: remove the enclosing `Some` and `?` operator
|
LL - to.and_then(|t| Some(t.magic?))
LL + to.and_then(|t| t.magic)
|

error: question mark operator is useless here
error: enclosing `Some` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:51:9
|
LL | Some(t.magic?)
| ^^^^^^^^^^^^^^ help: try removing question mark and `Some()`: `t.magic`
| ^^^^^^^^^^^^^^
|
help: remove the enclosing `Some` and `?` operator
|
LL - Some(t.magic?)
LL + t.magic
|

error: question mark operator is useless here
error: enclosing `Ok` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:57:12
|
LL | return Ok(tr.magic?);
| ^^^^^^^^^^^^^ help: try removing question mark and `Ok()`: `tr.magic`
| ^^^^^^^^^^^^^
|
help: remove the enclosing `Ok` and `?` operator
|
LL - return Ok(tr.magic?);
LL + return tr.magic;
|

error: question mark operator is useless here
error: enclosing `Ok` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:65:12
|
LL | return Ok(tr.magic?)
| ^^^^^^^^^^^^^ help: try removing question mark and `Ok()`: `tr.magic`
| ^^^^^^^^^^^^^
|
help: remove the enclosing `Ok` and `?` operator
|
LL - return Ok(tr.magic?)
LL + return tr.magic
|

error: question mark operator is useless here
error: enclosing `Ok` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:70:5
|
LL | Ok(tr.magic?)
| ^^^^^^^^^^^^^ help: try removing question mark and `Ok()`: `tr.magic`
| ^^^^^^^^^^^^^
|
help: remove the enclosing `Ok` and `?` operator
|
LL - Ok(tr.magic?)
LL + tr.magic
|

error: question mark operator is useless here
error: enclosing `Ok` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:75:21
|
LL | tr.and_then(|t| Ok(t.magic?))
| ^^^^^^^^^^^^ help: try removing question mark and `Ok()`: `t.magic`
| ^^^^^^^^^^^^
|
help: remove the enclosing `Ok` and `?` operator
|
LL - tr.and_then(|t| Ok(t.magic?))
LL + tr.and_then(|t| t.magic)
|

error: question mark operator is useless here
error: enclosing `Ok` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:84:9
|
LL | Ok(t.magic?)
| ^^^^^^^^^^^^ help: try removing question mark and `Ok()`: `t.magic`
| ^^^^^^^^^^^^
|
help: remove the enclosing `Ok` and `?` operator
|
LL - Ok(t.magic?)
LL + t.magic
|

error: question mark operator is useless here
error: enclosing `Ok` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:92:16
|
LL | return Ok(t.magic?);
| ^^^^^^^^^^^^ help: try removing question mark and `Ok()`: `t.magic`
| ^^^^^^^^^^^^
|
help: remove the enclosing `Ok` and `?` operator
|
LL - return Ok(t.magic?);
LL + return t.magic;
|

error: question mark operator is useless here
error: enclosing `Some` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:128:27
|
LL | || -> Option<_> { Some(Some($expr)?) }()
| ^^^^^^^^^^^^^^^^^^ help: try removing question mark and `Some()`: `Some($expr)`
| ^^^^^^^^^^^^^^^^^^
...
LL | let _x = some_and_qmark_in_macro!(x?);
| ---------------------------- in this macro invocation
|
= note: this error originates in the macro `some_and_qmark_in_macro` (in Nightly builds, run with -Z macro-backtrace for more info)
help: remove the enclosing `Some` and `?` operator
|
LL - || -> Option<_> { Some(Some($expr)?) }()
LL + || -> Option<_> { Some($expr) }()
|

error: question mark operator is useless here
error: enclosing `Some` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:140:5
|
LL | Some(to.magic?)
| ^^^^^^^^^^^^^^^ help: try removing question mark and `Some()`: `to.magic`
| ^^^^^^^^^^^^^^^
|
help: remove the enclosing `Some` and `?` operator
|
LL - Some(to.magic?)
LL + to.magic
|

error: question mark operator is useless here
error: enclosing `Ok` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:149:5
|
LL | Ok(s.magic?)
| ^^^^^^^^^^^^ help: try removing question mark and `Ok()`: `s.magic`
| ^^^^^^^^^^^^
|
help: remove the enclosing `Ok` and `?` operator
|
LL - Ok(s.magic?)
LL + s.magic
|

error: question mark operator is useless here
error: enclosing `Some` and `?` operator are unneeded
--> tests/ui/needless_question_mark.rs:154:7
|
LL | { Some(a?) }
| ^^^^^^^^ help: try removing question mark and `Some()`: `a`
| ^^^^^^^^
|
help: remove the enclosing `Some` and `?` operator
|
LL - { Some(a?) }
LL + { a }
|

error: aborting due to 15 previous errors

5 changes: 5 additions & 0 deletions tests/ui/question_mark.fixed
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -301,6 +301,11 @@ fn pattern() -> Result<(), PatternedError> {
res
}

fn expect_expr(a: Option<usize>) -> Option<usize> {
#[expect(clippy::needless_question_mark)]
Some(a?)
}

fn main() {}

// `?` is not the same as `return None;` if inside of a try block
Expand Down
5 changes: 5 additions & 0 deletions tests/ui/question_mark.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -371,6 +371,11 @@ fn pattern() -> Result<(), PatternedError> {
res
}

fn expect_expr(a: Option<usize>) -> Option<usize> {
#[expect(clippy::needless_question_mark)]
Some(a?)
}

fn main() {}

// `?` is not the same as `return None;` if inside of a try block
Expand Down
Loading