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Shorten error message for callable with wrong return type

Browse source 
```
error: expected `{closure@...}` to return `Ret`, but it returns `Other`
```
instead of
```
error: expected `{closure@...}` to be a closure that returns `Ret`, but it returns `Other`
```
This commit is contained in:
Esteban Küber 2025-02-02 01:00:12 +00:00
parent 7f36543a48
commit 9ebbba4ad9
23 changed files with 29 additions and 31 deletions
Download patch file Download diff file Expand all files Collapse all files

4
compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
View file

@ -1518,7 +1518,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
with_forced_trimmed_paths! {
if self.tcx.is_lang_item(projection_term.def_id, LangItem::FnOnceOutput) {
let fn_kind = self_ty.prefix_string(self.tcx);
let (span, closure_span) = if let ty::Closure(def_id, _) = self_ty.kind() {
let def_span = self.tcx.def_span(def_id);
if let Some(local_def_id) = def_id.as_local()
@ -1555,8 +1554,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
_ => self_ty.to_string(),
};
Some((format!(
"expected `{item}` to be a {fn_kind} that returns `{expected_ty}`, but it \
returns `{normalized_ty}`",
"expected `{item}` to return `{expected_ty}`, but it returns `{normalized_ty}`",
), span, closure_span))
} else if self.tcx.is_lang_item(trait_def_id, LangItem::Future) {
Some((format!(

2
tests/ui/async-await/async-closures/is-not-fn.current.stderr
View file

@ -1,4 +1,4 @@
error[E0271]: expected `{async closure@is-not-fn.rs:8:14}` to be a closure that returns `()`, but it returns `{async closure body@$DIR/is-not-fn.rs:8:23: 8:25}`
error[E0271]: expected `{async closure@is-not-fn.rs:8:14}` to return `()`, but it returns `{async closure body@$DIR/is-not-fn.rs:8:23: 8:25}`
--> $DIR/is-not-fn.rs:8:14
|
LL | needs_fn(async || {});

2
tests/ui/async-await/async-closures/is-not-fn.next.stderr
View file

@ -1,4 +1,4 @@
error[E0271]: expected `{async closure@is-not-fn.rs:8:14}` to be a closure that returns `()`, but it returns `{async closure body@$DIR/is-not-fn.rs:8:23: 8:25}`
error[E0271]: expected `{async closure@is-not-fn.rs:8:14}` to return `()`, but it returns `{async closure body@$DIR/is-not-fn.rs:8:23: 8:25}`
--> $DIR/is-not-fn.rs:8:14
|
LL | needs_fn(async || {});

2
tests/ui/async-await/async-closures/is-not-fn.rs
View file

@ -6,5 +6,5 @@
fn main() {
fn needs_fn(x: impl FnOnce()) {}
needs_fn(async || {});
//~^ ERROR expected `{async closure@is-not-fn.rs:8:14}` to be a closure that returns `()`
//~^ ERROR expected `{async closure@is-not-fn.rs:8:14}` to return `()`
}

2
tests/ui/async-await/dont-ice-for-type-mismatch-in-closure-in-async.stderr
View file

@ -20,7 +20,7 @@ LL | true
= note: expected enum `Option<()>`
found type `bool`
error[E0271]: expected `{closure@dont-ice-for-type-mismatch-in-closure-in-async.rs:6:10}` to be a closure that returns `bool`, but it returns `Option<()>`
error[E0271]: expected `{closure@dont-ice-for-type-mismatch-in-closure-in-async.rs:6:10}` to return `bool`, but it returns `Option<()>`
--> $DIR/dont-ice-for-type-mismatch-in-closure-in-async.rs:6:16
|
LL | call(|| -> Option<()> {

6
tests/ui/async-await/issue-98634.rs
View file

@ -43,8 +43,8 @@ impl Runtime {
fn main() {
Runtime.block_on(async {
StructAsync { callback }.await;
//~^ ERROR expected `callback` to be a fn item that returns `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
//~| ERROR expected `callback` to be a fn item that returns `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
//~| ERROR expected `callback` to be a fn item that returns `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
//~^ ERROR expected `callback` to return `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
//~| ERROR expected `callback` to return `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
//~| ERROR expected `callback` to return `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
});
}

6
tests/ui/async-await/issue-98634.stderr
View file

@ -1,4 +1,4 @@
error[E0271]: expected `callback` to be a fn item that returns `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
error[E0271]: expected `callback` to return `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
--> $DIR/issue-98634.rs:45:23
|
LL | StructAsync { callback }.await;
@ -10,7 +10,7 @@ note: required by a bound in `StructAsync`
LL | pub struct StructAsync<F: Fn() -> Pin<Box<dyn Future<Output = ()>>>> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `StructAsync`
error[E0271]: expected `callback` to be a fn item that returns `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
error[E0271]: expected `callback` to return `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
--> $DIR/issue-98634.rs:45:9
|
LL | StructAsync { callback }.await;
@ -22,7 +22,7 @@ note: required by a bound in `StructAsync`
LL | pub struct StructAsync<F: Fn() -> Pin<Box<dyn Future<Output = ()>>>> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `StructAsync`
error[E0271]: expected `callback` to be a fn item that returns `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
error[E0271]: expected `callback` to return `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
--> $DIR/issue-98634.rs:45:34
|
LL | StructAsync { callback }.await;

4
tests/ui/closures/return-type-doesnt-match-bound.rs
View file

@ -5,7 +5,7 @@ fn foo<F>(f: F) -> ()
where
F: FnOnce() -> Result<(), Box<dyn Error>>,
{
f().or_else(|e| -> ! { //~ ERROR to be a closure that returns
f().or_else(|e| -> ! { //~ ERROR to return
eprintln!("{:?}", e);
exit(1)
});
@ -15,7 +15,7 @@ fn bar<F>(f: F) -> ()
where
F: FnOnce() -> Result<(), Box<dyn Error>>,
{
let c = |e| -> ! { //~ ERROR to be a closure that returns
let c = |e| -> ! { //~ ERROR to return
eprintln!("{:?}", e);
exit(1)
};

4
tests/ui/closures/return-type-doesnt-match-bound.stderr
View file

@ -1,4 +1,4 @@
error[E0271]: expected `{closure@return-type-doesnt-match-bound.rs:8:17}` to be a closure that returns `Result<(), _>`, but it returns `!`
error[E0271]: expected `{closure@return-type-doesnt-match-bound.rs:8:17}` to return `Result<(), _>`, but it returns `!`
--> $DIR/return-type-doesnt-match-bound.rs:8:24
|
LL | f().or_else(|e| -> ! {
@ -13,7 +13,7 @@ LL | f().or_else(|e| -> ! {
note: required by a bound in `Result::<T, E>::or_else`
--> $SRC_DIR/core/src/result.rs:LL:COL
error[E0271]: expected `{closure@return-type-doesnt-match-bound.rs:18:13}` to be a closure that returns `Result<(), _>`, but it returns `!`
error[E0271]: expected `{closure@return-type-doesnt-match-bound.rs:18:13}` to return `Result<(), _>`, but it returns `!`
--> $DIR/return-type-doesnt-match-bound.rs:18:20
|
LL | let c = |e| -> ! {

2
tests/ui/higher-ranked/trait-bounds/issue-62203-hrtb-ice.rs
View file

@ -39,7 +39,7 @@ fn main() {
L { //~ ERROR type mismatch
f: |x| {
drop(x);
Unit4 //~ ERROR to be a closure that returns `Unit3`, but it returns `Unit4`
Unit4 //~ ERROR to return `Unit3`, but it returns `Unit4`
},
},
);

2
tests/ui/higher-ranked/trait-bounds/issue-62203-hrtb-ice.stderr
View file

@ -29,7 +29,7 @@ LL | where
LL | F: for<'r> T0<'r, (<Self as Ty<'r>>::V,), O = <B as Ty<'r>>::V>,
| ^^^^^^^^^^^^^^^^^^^^ required by this bound in `T1::m`
error[E0271]: expected `{closure@issue-62203-hrtb-ice.rs:40:16}` to be a closure that returns `Unit3`, but it returns `Unit4`
error[E0271]: expected `{closure@issue-62203-hrtb-ice.rs:40:16}` to return `Unit3`, but it returns `Unit4`
--> $DIR/issue-62203-hrtb-ice.rs:42:17
|
LL | let v = Unit2.m(

2
tests/ui/intrinsics/const-eval-select-bad.rs
View file

@ -30,7 +30,7 @@ fn baz(n: bool) -> i32 {
const fn return_ty_mismatch() {
const_eval_select((1,), foo, bar);
//~^ ERROR expected `bar` to be a fn item that returns `i32`, but it returns `bool`
//~^ ERROR expected `bar` to return `i32`, but it returns `bool`
}
const fn args_ty_mismatch() {

2
tests/ui/intrinsics/const-eval-select-bad.stderr
View file

@ -60,7 +60,7 @@ LL | const_eval_select((), 42, 0xDEADBEEF);
= note: expected a function item, found {integer}
= help: consult the documentation on `const_eval_select` for more information
error[E0271]: expected `bar` to be a fn item that returns `i32`, but it returns `bool`
error[E0271]: expected `bar` to return `i32`, but it returns `bool`
--> $DIR/const-eval-select-bad.rs:32:34
|
LL | const_eval_select((1,), foo, bar);

2
tests/ui/lint/issue-106991.rs
View file

@ -3,7 +3,7 @@ fn foo(items: &mut Vec<u8>) {
}
fn bar() -> impl Iterator<Item = i32> {
//~^ ERROR expected `foo` to be a fn item that returns `i32`, but it returns `()` [E0271]
//~^ ERROR expected `foo` to return `i32`, but it returns `()` [E0271]
let mut x: Vec<Vec<u8>> = vec![vec![0, 2, 1], vec![5, 4, 3]];
x.iter_mut().map(foo)
}

2
tests/ui/lint/issue-106991.stderr
View file

@ -1,4 +1,4 @@
error[E0271]: expected `foo` to be a fn item that returns `i32`, but it returns `()`
error[E0271]: expected `foo` to return `i32`, but it returns `()`
--> $DIR/issue-106991.rs:5:13
|
LL | fn bar() -> impl Iterator<Item = i32> {

2
tests/ui/never_type/fallback-closure-wrap.fallback.stderr
View file

@ -1,4 +1,4 @@
error[E0271]: expected `{closure@fallback-closure-wrap.rs:18:40}` to be a closure that returns `()`, but it returns `!`
error[E0271]: expected `{closure@fallback-closure-wrap.rs:18:40}` to return `()`, but it returns `!`
--> $DIR/fallback-closure-wrap.rs:19:9
|
LL | let error = Closure::wrap(Box::new(move || {

2
tests/ui/never_type/fallback-closure-wrap.rs
View file

@ -17,7 +17,7 @@ use std::marker::PhantomData;
fn main() {
let error = Closure::wrap(Box::new(move || {
panic!("Can't connect to server.");
//[fallback]~^ to be a closure that returns `()`, but it returns `!`
//[fallback]~^ to return `()`, but it returns `!`
}) as Box<dyn FnMut()>);
}

2
tests/ui/suggestions/dont-suggest-boxing-async-closure-body.rs
View file

@ -7,6 +7,6 @@ fn bar<X>(x: Box<dyn FnOnce() -> X>) {}
fn main() {
foo(async move || {});
//~^ ERROR expected `{async closure@dont-suggest-boxing-async-closure-body.rs:9:9}` to be a closure that returns `Box<_>`
//~^ ERROR expected `{async closure@dont-suggest-boxing-async-closure-body.rs:9:9}` to return `Box<_>`
bar(async move || {}); //~ ERROR mismatched types
}

2
tests/ui/suggestions/dont-suggest-boxing-async-closure-body.stderr
View file

@ -1,4 +1,4 @@
error[E0271]: expected `{async closure@dont-suggest-boxing-async-closure-body.rs:9:9}` to be a closure that returns `Box<_>`, but it returns `{async closure body@$DIR/dont-suggest-boxing-async-closure-body.rs:9:23: 9:25}`
error[E0271]: expected `{async closure@dont-suggest-boxing-async-closure-body.rs:9:9}` to return `Box<_>`, but it returns `{async closure body@$DIR/dont-suggest-boxing-async-closure-body.rs:9:23: 9:25}`
--> $DIR/dont-suggest-boxing-async-closure-body.rs:9:9
|
LL | foo(async move || {});

2
tests/ui/type-alias-impl-trait/issue-98604.rs
View file

@ -7,5 +7,5 @@ async fn test() {}
#[allow(unused_must_use)]
fn main() {
Box::new(test) as AsyncFnPtr;
//~^ ERROR expected `test` to be a fn item that returns `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>
//~^ ERROR expected `test` to return `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>
}

2
tests/ui/type-alias-impl-trait/issue-98604.stderr
View file

@ -1,4 +1,4 @@
error[E0271]: expected `test` to be a fn item that returns `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
error[E0271]: expected `test` to return `Pin<Box<dyn Future<Output = ()>>>`, but it returns `impl Future<Output = ()>`
--> $DIR/issue-98604.rs:9:5
|
LL | Box::new(test) as AsyncFnPtr;

2
tests/ui/type-alias-impl-trait/issue-98608.rs
View file

@ -4,7 +4,7 @@ fn hi() -> impl Sized {
fn main() {
let b: Box<dyn Fn() -> Box<u8>> = Box::new(hi);
//~^ ERROR expected `hi` to be a fn item that returns `Box<u8>`, but it returns `impl Sized`
//~^ ERROR expected `hi` to return `Box<u8>`, but it returns `impl Sized`
let boxed = b();
let null = *boxed;
println!("{null:?}");

2
tests/ui/type-alias-impl-trait/issue-98608.stderr
View file

@ -1,4 +1,4 @@
error[E0271]: expected `hi` to be a fn item that returns `Box<u8>`, but it returns `impl Sized`
error[E0271]: expected `hi` to return `Box<u8>`, but it returns `impl Sized`
--> $DIR/issue-98608.rs:6:39
|
LL | fn hi() -> impl Sized {