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fix: ignore pattern_type_mismatch when external macro owns the match

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changelog: [`pattern_type_mismatch`]: fix unwanted hit in external macro
This commit is contained in:
Kristof Mattei 2025-07-17 15:44:30 -07:00
parent e62e27bf5b
commit b2c4e6de2f
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4 changed files with 37 additions and 9 deletions
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6
clippy_lints/src/pattern_type_mismatch.rs
View file

@ -96,6 +96,12 @@ impl<'tcx> LateLintPass<'tcx> for PatternTypeMismatch {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if let ExprKind::Match(_, arms, _) = expr.kind {
// if the match is generated by an external macro, the writer does not control
// how the scrutinee (`match &scrutiny { ... }`) is matched
if expr.span.in_external_macro(cx.sess().source_map()) {
return;
}
for arm in arms {
let pat = &arm.pat;
if apply_lint(cx, pat, DerefPossible::Possible) {

13
tests/ui/pattern_type_mismatch/auxiliary/external.rs Normal file
View file

@ -0,0 +1,13 @@
//! **FAKE** external macro crate.
#[macro_export]
macro_rules! macro_with_match {
( $p:pat ) => {
let something = ();
match &something {
$p => true,
_ => false,
}
};
}

9
tests/ui/pattern_type_mismatch/syntax.rs
View file

@ -6,6 +6,9 @@
clippy::single_match
)]
//@aux-build:external.rs
use external::macro_with_match;
fn main() {}
fn syntax_match() {
@ -159,3 +162,9 @@ fn macro_expansion() {
let value = &Some(23);
matching_macro!(value);
}
fn external_macro_expansion() {
macro_with_match! {
()
};
}

18
tests/ui/pattern_type_mismatch/syntax.stderr
View file

@ -1,5 +1,5 @@
error: type of pattern does not match the expression type
--> tests/ui/pattern_type_mismatch/syntax.rs:16:9
--> tests/ui/pattern_type_mismatch/syntax.rs:19:9
|
LL | Some(_) => (),
| ^^^^^^^
@ -9,7 +9,7 @@ LL | Some(_) => (),
= help: to override `-D warnings` add `#[allow(clippy::pattern_type_mismatch)]`
error: type of pattern does not match the expression type
--> tests/ui/pattern_type_mismatch/syntax.rs:36:12
--> tests/ui/pattern_type_mismatch/syntax.rs:39:12
|
LL | if let Some(_) = ref_value {}
| ^^^^^^^
@ -17,7 +17,7 @@ LL | if let Some(_) = ref_value {}
= help: use `*` to dereference the match expression or explicitly match against a `&_` pattern and adjust the enclosed variable bindings
error: type of pattern does not match the expression type
--> tests/ui/pattern_type_mismatch/syntax.rs:48:15
--> tests/ui/pattern_type_mismatch/syntax.rs:51:15
|
LL | while let Some(_) = ref_value {
| ^^^^^^^
@ -25,7 +25,7 @@ LL | while let Some(_) = ref_value {
= help: use `*` to dereference the match expression or explicitly match against a `&_` pattern and adjust the enclosed variable bindings
error: type of pattern does not match the expression type
--> tests/ui/pattern_type_mismatch/syntax.rs:68:9
--> tests/ui/pattern_type_mismatch/syntax.rs:71:9
|
LL | for (_a, _b) in slice.iter() {}
| ^^^^^^^^
@ -33,7 +33,7 @@ LL | for (_a, _b) in slice.iter() {}
= help: explicitly match against a `&_` pattern and adjust the enclosed variable bindings
error: type of pattern does not match the expression type
--> tests/ui/pattern_type_mismatch/syntax.rs:79:9
--> tests/ui/pattern_type_mismatch/syntax.rs:82:9
|
LL | let (_n, _m) = ref_value;
| ^^^^^^^^
@ -41,7 +41,7 @@ LL | let (_n, _m) = ref_value;
= help: use `*` to dereference the match expression or explicitly match against a `&_` pattern and adjust the enclosed variable bindings
error: type of pattern does not match the expression type
--> tests/ui/pattern_type_mismatch/syntax.rs:89:12
--> tests/ui/pattern_type_mismatch/syntax.rs:92:12
|
LL | fn foo((_a, _b): &(i32, i32)) {}
| ^^^^^^^^
@ -49,7 +49,7 @@ LL | fn foo((_a, _b): &(i32, i32)) {}
= help: explicitly match against a `&_` pattern and adjust the enclosed variable bindings
error: type of pattern does not match the expression type
--> tests/ui/pattern_type_mismatch/syntax.rs:104:10
--> tests/ui/pattern_type_mismatch/syntax.rs:107:10
|
LL | foo(|(_a, _b)| ());
| ^^^^^^^^
@ -57,7 +57,7 @@ LL | foo(|(_a, _b)| ());
= help: explicitly match against a `&_` pattern and adjust the enclosed variable bindings
error: type of pattern does not match the expression type
--> tests/ui/pattern_type_mismatch/syntax.rs:121:9
--> tests/ui/pattern_type_mismatch/syntax.rs:124:9
|
LL | Some(_) => (),
| ^^^^^^^
@ -65,7 +65,7 @@ LL | Some(_) => (),
= help: use `*` to dereference the match expression or explicitly match against a `&_` pattern and adjust the enclosed variable bindings
error: type of pattern does not match the expression type
--> tests/ui/pattern_type_mismatch/syntax.rs:142:17
--> tests/ui/pattern_type_mismatch/syntax.rs:145:17
|
LL | Some(_) => (),
| ^^^^^^^