Commit 2574810b228d53518cc2a13f2ee473195932a999 | rust

author	bors <bors@rust-lang.org> 2026-06-28 15:52:45 UTC
committer	bors <bors@rust-lang.org> 2026-06-28 15:52:45 UTC
log	2574810b228d53518cc2a13f2ee473195932a999
tree	bbc79ce2af951a45bba0dbd2ae12b732e7994b19
parent	b4486cacf58926f02e451d96e71e20882faf5453
parent	412fd6b75bf1b15209af52a5ae865f91081ce4a4

Auto merge of #158524 - JonathanBrouwer:rollup-75ZlceV, r=JonathanBrouwer

Rollup of 4 pull requests

Successful merges:

 - rust-lang/rust#158486 (std: treat ENFILE as transient in the pidfd support probe)
 - rust-lang/rust#158454 (regression test for `Trait<A><B>` in "consider further restricting this bound" suggestion)
 - rust-lang/rust#158518 (Fix mixed use of "a" / "an" article in E0277)
 - rust-lang/rust#158519 (add crashtests [2/N])

88 files changed, 330 insertions(+), 128 deletions(-)

library/core/src/ops/function.rs+3-3

...	...	@@ -67,7 +67,7 @@ use crate::marker::Tuple;
67	67	// SAFETY: tidy is not smart enough to tell that the below unsafe block is a string
68	68	label = "call the function in a closure: `\|\| unsafe {{ /* code */ }}`"
69	69	),
70		message = "expected a `{This:resolved}` closure, found `{Self}`",
	70	message = "expected an `{This:resolved}` closure, found `{Self}`",
71	71	label = "expected an `{This:resolved}` closure, found `{Self}`"
72	72	)]
73	73	#[fundamental] // so that regex can rely that `&str: !FnMut`
...	...	@@ -154,7 +154,7 @@ pub const trait Fn<Args: Tuple>: [const] FnMut<Args> {
154	154	// SAFETY: tidy is not smart enough to tell that the below unsafe block is a string
155	155	label = "call the function in a closure: `\|\| unsafe {{ /* code */ }}`"
156	156	),
157		message = "expected a `{This:resolved}` closure, found `{Self}`",
	157	message = "expected an `{This:resolved}` closure, found `{Self}`",
158	158	label = "expected an `{This:resolved}` closure, found `{Self}`"
159	159	)]
160	160	#[fundamental] // so that regex can rely that `&str: !FnMut`
...	...	@@ -233,7 +233,7 @@ pub const trait FnMut<Args: Tuple>: FnOnce<Args> {
233	233	// SAFETY: tidy is not smart enough to tell that the below unsafe block is a string
234	234	label = "call the function in a closure: `\|\| unsafe {{ /* code */ }}`"
235	235	),
236		message = "expected a `{This:resolved}` closure, found `{Self}`",
	236	message = "expected an `{This:resolved}` closure, found `{Self}`",
237	237	label = "expected an `{This:resolved}` closure, found `{Self}`"
238	238	)]
239	239	#[fundamental] // so that regex can rely that `&str: !FnMut`

library/std/src/sys/process/unix/unix.rs+2-2

...	...	@@ -510,8 +510,8 @@ impl Command {
510	510	support = SPAWN;
511	511	}
512	512	}
513		Err(e) if e.raw_os_error() == Some(libc::EMFILE) => {
514		// We're temporarily(?) out of file descriptors. In this case pidfd_spawnp would also fail
	513	Err(e) if matches!(e.raw_os_error(), Some(libc::EMFILE \| libc::ENFILE \| libc::ENOMEM)) => {
	514	// We're temporarily(?) out of file descriptors or memory. In this case pidfd_spawnp would also fail
515	515	// Don't update the support flag so we can probe again later.
516	516	return Err(e)
517	517	}

tests/crashes/149748.rs created+13

...	...	@@ -0,0 +1,13 @@
	1	//@ known-bug: #149748
	2	//@ edition: 2024
	3	//@ compile-flags: -Zmir-enable-passes=+Inline -Zmir-enable-passes=+ReferencePropagation -Zlint-mir
	4
	5	#![feature(gen_blocks)]
	6	gen fn foo(z: i32) -> i32 {
	7	yield z;
	8	z;
	9	}
	10	pub fn main() {
	11	let mut iter = foo(3);
	12	assert_eq!(iter.next(), Some(3))
	13	}

tests/crashes/150040.rs created+7

...	...	@@ -0,0 +1,7 @@
	1	//@ known-bug: #150040
	2
	3	fn main() {
	4	let [(ref a, b), x];
	5	a = "";
	6	b = 5;
	7	}

tests/crashes/150049.rs created+12

...	...	@@ -0,0 +1,12 @@
	1	//@ known-bug: #150049
	2	#![feature(min_generic_const_args)]
	3	#![feature(inherent_associated_types)]
	4	struct Foo<'a> {
	5	x: &'a (),
	6	}
	7
	8	impl<'a> Foo<'a> {
	9	fn foo(_: [u8; Foo::X]) { std::mem::transmute([4]) }
	10	}
	11
	12	fn main() {}

tests/crashes/150128.rs created+8

...	...	@@ -0,0 +1,8 @@
	1	//@ known-bug: #150128
	2	fn main() {
	3	match 0 {
	4	_ => \|\| (),
	5	_ => \|\| (),
	6	_ => (\|\| ()) as unsafe fn,
	7	};
	8	}

tests/crashes/150296.rs created+14

...	...	@@ -0,0 +1,14 @@
	1	//@ known-bug: #150296
	2	#[derive(PartialEq)]
	3	pub struct Thing<const N: usize>;
	4
	5	impl<const N: usize> Thing<N> {
	6	const A: Self = Thing;
	7	}
	8
	9	fn broken<const N: usize>(x: Thing<N>) {
	10	match x {
	11	<Thing<N>>::A => {}
	12	_ => {}
	13	}
	14	}

tests/crashes/150387.rs created+13

...	...	@@ -0,0 +1,13 @@
	1	//@ known-bug: #150387
	2	#![feature(min_specialization)]
	3	#![allow(dead_code)]
	4
	5	struct Thing<T>(T) where [T]: Sized;
	6
	7	impl<T> Drop for Thing<T> where [T]: Sized {
	8	default fn drop(&mut self) {}
	9	}
	10	impl<T> Drop for Thing<T> where [T]: Sized {
	11	fn drop(&mut self) {}
	12	}
	13	fn main() {}

tests/crashes/150403.rs created+26

...	...	@@ -0,0 +1,26 @@
	1	//@ known-bug: #150403
	2	#![feature(non_lifetime_binders)]
	3
	4	trait A {
	5	type GAT<T>: A;
	6	fn foo<T>(self, t: T) -> Self::GAT<T>
	7	where
	8	Self: Sized;
	9	}
	10
	11	trait B: A where
	12	for<T> Self::GAT<T>: B,
	13	{
	14	fn bar<T>(self) -> Self::GAT<T>
	15	where
	16	Self: Sized;
	17
	18	fn baz<T>(self, t: T) -> Self::GAT<T>
	19	where
	20	Self: Sized,
	21	{
	22	self.foo(t).bar()
	23	}
	24	}
	25
	26	fn main() {}

tests/crashes/150517.rs created+15

...	...	@@ -0,0 +1,15 @@
	1	//@ known-bug: #150517
	2	trait Stream {
	3	type Item;
	4	fn next(self) -> ();
	5	}
	6	impl Stream for &'a () {}
	7	impl<'a, A> Stream for <&A as Stream>::Item {}
	8	trait StreamExt {
	9	fn f(self) -> ()
	10	where
	11	for<'b> &'b A: Stream,
	12	{
	13	self.next()
	14	}
	15	}

tests/crashes/150545.rs created+8

...	...	@@ -0,0 +1,8 @@
	1	//@ known-bug: #150545
	2	#![feature(non_lifetime_binders)]
	3	trait Foo: for<T> Bar<T> {
	4	type Item;
	5	fn next(self) -> Self::Item;
	6	}
	7	trait Bar<T> {}
	8	fn main() {}

tests/crashes/150749.rs created+12

...	...	@@ -0,0 +1,12 @@
	1	//@ known-bug: #150749
	2	#![feature(min_generic_const_args)]
	3
	4	trait CollectArray {
	5	fn inner_array();
	6	}
	7	impl CollectArray for () {
	8	fn inner_array() {
	9	let temp_ptr: [(); Self];
	10	}
	11	}
	12	fn main() {}

tests/crashes/150969.rs created+7

...	...	@@ -0,0 +1,7 @@
	1	//@ known-bug: #150969
	2	#![feature(generic_const_exprs)]
	3	#![feature(min_generic_const_args)]
	4
	5	fn pass_enum<const N : usize, const M : usize = const {N}> {
	6	pass_enum::<{None}>
	7	}

tests/crashes/151069.rs created+16

...	...	@@ -0,0 +1,16 @@
	1	//@ known-bug: #151069
	2	trait Trait {
	3	type Assoc2;
	4	}
	5	struct Bar;
	6	impl Trait for Bar
	7	where
	8	<Bar as Trait>::Assoc2: Trait,
	9	{
	10	type Assoc2 = ();
	11	}
	12	struct Foo {
	13	field: <Bar as Trait>::Assoc2,
	14	}
	15	static FOO2: &Foo = 0;
	16	fn main() {}

tests/ui/abi/bad-custom.rs+1-1

...	...	@@ -100,7 +100,7 @@ async unsafe extern "custom" fn no_async_fn() {
100	100	}
101	101
102	102	fn no_promotion_to_fn_trait(f: unsafe extern "custom" fn()) -> impl Fn() {
103		//~^ ERROR expected a `Fn()` closure, found `unsafe extern "custom" fn()`
	103	//~^ ERROR expected an `Fn()` closure, found `unsafe extern "custom" fn()`
104	104	f
105	105	}
106	106

tests/ui/abi/bad-custom.stderr+1-1

...	...	@@ -184,7 +184,7 @@ LL + #[unsafe(naked)]
184	184	LL \| async unsafe extern "custom" fn no_async_fn() {
185	185	\|
186	186
187		error[E0277]: expected a `Fn()` closure, found `unsafe extern "custom" fn()`
	187	error[E0277]: expected an `Fn()` closure, found `unsafe extern "custom" fn()`
188	188	--> $DIR/bad-custom.rs:102:64
189	189	\|
190	190	LL \| fn no_promotion_to_fn_trait(f: unsafe extern "custom" fn()) -> impl Fn() {

tests/ui/associated-types/normalization-ice-issue-149746.rs+4-4

...	...	@@ -4,14 +4,14 @@ trait Owner { type Ty<T: FnMut()>; }
4	4	impl Owner for () { type Ty<T: FnMut()> = T; }
5	5	pub struct Warns<T> {
6	6	_significant_drop: <() as Owner>::Ty<T>,
7		//~^ ERROR expected a `FnMut()` closure, found `T`
	7	//~^ ERROR expected an `FnMut()` closure, found `T`
8	8	field: String,
9	9	}
10	10	pub fn test<T>(w: Warns<T>) {
11		//~^ ERROR expected a `FnMut()` closure, found `T`
	11	//~^ ERROR expected an `FnMut()` closure, found `T`
12	12	_ = \|\| w.field
13		//~^ ERROR expected a `FnMut()` closure, found `T`
14		//~\| ERROR expected a `FnMut()` closure, found `T`
	13	//~^ ERROR expected an `FnMut()` closure, found `T`
	14	//~\| ERROR expected an `FnMut()` closure, found `T`
15	15	//~\| WARN: changes to closure capture in Rust 2021 will affect drop order
16	16	}
17	17	fn main() {}

tests/ui/associated-types/normalization-ice-issue-149746.stderr+4-4

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnMut()` closure, found `T`
	1	error[E0277]: expected an `FnMut()` closure, found `T`
2	2	--> $DIR/normalization-ice-issue-149746.rs:6:24
3	3	\|
4	4	LL \| _significant_drop: <() as Owner>::Ty<T>,
...	...	@@ -35,7 +35,7 @@ help: add a dummy let to cause `w` to be fully captured
35	35	LL \| _ = \|\| { let _ = &w; w.field }
36	36	\| +++++++++++++ +
37	37
38		error[E0277]: expected a `FnMut()` closure, found `T`
	38	error[E0277]: expected an `FnMut()` closure, found `T`
39	39	--> $DIR/normalization-ice-issue-149746.rs:12:9
40	40	\|
41	41	LL \| _ = \|\| w.field
...	...	@@ -48,7 +48,7 @@ note: required by a bound in `Owner::Ty`
48	48	LL \| trait Owner { type Ty<T: FnMut()>; }
49	49	\| ^^^^^^^ required by this bound in `Owner::Ty`
50	50
51		error[E0277]: expected a `FnMut()` closure, found `T`
	51	error[E0277]: expected an `FnMut()` closure, found `T`
52	52	--> $DIR/normalization-ice-issue-149746.rs:10:16
53	53	\|
54	54	LL \| pub fn test<T>(w: Warns<T>) {
...	...	@@ -61,7 +61,7 @@ note: required by a bound in `Owner::Ty`
61	61	LL \| trait Owner { type Ty<T: FnMut()>; }
62	62	\| ^^^^^^^ required by this bound in `Owner::Ty`
63	63
64		error[E0277]: expected a `FnMut()` closure, found `T`
	64	error[E0277]: expected an `FnMut()` closure, found `T`
65	65	--> $DIR/normalization-ice-issue-149746.rs:12:9
66	66	\|
67	67	LL \| _ = \|\| w.field

tests/ui/async-await/async-fn/impl-header.rs+1-1

...	...	@@ -6,7 +6,7 @@ impl async Fn<()> for F {}
6	6	//~^ ERROR `async` trait implementations are unsupported
7	7	//~\| ERROR the precise format of `Fn`-family traits' type parameters is subject to change
8	8	//~\| ERROR manual implementations of `Fn` are experimental
9		//~\| ERROR expected a `FnMut()` closure, found `F`
	9	//~\| ERROR expected an `FnMut()` closure, found `F`
10	10	//~\| ERROR not all trait items implemented, missing: `call`
11	11
12	12	fn main() {}

tests/ui/async-await/async-fn/impl-header.stderr+1-1

...	...	@@ -30,7 +30,7 @@ LL \| impl async Fn<()> for F {}
30	30	\|
31	31	= help: implement the missing item: `fn call(&self, _: ()) -> <Self as FnOnce<()>>::Output { todo!() }`
32	32
33		error[E0277]: expected a `FnMut()` closure, found `F`
	33	error[E0277]: expected an `FnMut()` closure, found `F`
34	34	--> $DIR/impl-header.rs:5:23
35	35	\|
36	36	LL \| impl async Fn<()> for F {}

tests/ui/cast/raw-ptr-to-dyn-fn-raw-ptr.rs+1-1

...	...	@@ -4,6 +4,6 @@ fn main() {
4	4	let ptr: *mut () = core::ptr::null_mut();
5	5	let _: &mut dyn Fn() = unsafe {
6	6	&mut (ptr as mut dyn Fn())
7		//~^ ERROR expected a `Fn()` closure, found `()`
	7	//~^ ERROR expected an `Fn()` closure, found `()`
8	8	};
9	9	}

tests/ui/cast/raw-ptr-to-dyn-fn-raw-ptr.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn()` closure, found `()`
	1	error[E0277]: expected an `Fn()` closure, found `()`
2	2	--> $DIR/raw-ptr-to-dyn-fn-raw-ptr.rs:6:16
3	3	\|
4	4	LL \| &mut (ptr as mut dyn Fn())

tests/ui/closures/closure-expected.rs+1-1

...	...	@@ -1,5 +1,5 @@
1	1	fn main() {
2	2	let x = Some(1);
3	3	let y = x.or_else(4);
4		//~^ ERROR expected a `FnOnce()` closure, found `{integer}`
	4	//~^ ERROR expected an `FnOnce()` closure, found `{integer}`
5	5	}

tests/ui/closures/closure-expected.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnOnce()` closure, found `{integer}`
	1	error[E0277]: expected an `FnOnce()` closure, found `{integer}`
2	2	--> $DIR/closure-expected.rs:3:23
3	3	\|
4	4	LL \| let y = x.or_else(4);

tests/ui/closures/coerce-unsafe-to-closure.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnOnce(&str)` closure, found `unsafe fn(_) -> _ {std::intrinsics::transmute::<_, _>}`
	1	error[E0277]: expected an `FnOnce(&str)` closure, found `unsafe fn(_) -> _ {std::intrinsics::transmute::<_, _>}`
2	2	--> $DIR/coerce-unsafe-to-closure.rs:2:44
3	3	\|
4	4	LL \| let x: Option<&[u8]> = Some("foo").map(std::mem::transmute);

tests/ui/contracts/empty-ensures.rs+1-1

...	...	@@ -6,7 +6,7 @@ extern crate core;
6	6	use core::contracts::ensures;
7	7
8	8	#[ensures()]
9		//~^ ERROR expected a `Fn(&_)` closure, found `()` [E0277]
	9	//~^ ERROR expected an `Fn(&_)` closure, found `()` [E0277]
10	10	fn foo(x: u32) -> u32 {
11	11	x * 2
12	12	}

tests/ui/contracts/empty-ensures.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn(&_)` closure, found `()`
	1	error[E0277]: expected an `Fn(&_)` closure, found `()`
2	2	--> $DIR/empty-ensures.rs:8:1
3	3	\|
4	4	LL \| #[ensures()]

tests/ui/expr/malformed_closure/block_instead_of_closure_in_arg.rs+1-1

...	...	@@ -1,6 +1,6 @@
1	1	fn main() {
2	2	let number = 2;
3		Some(true).filter({ //~ ERROR expected a `FnOnce(&bool)` closure, found `bool`
	3	Some(true).filter({ //~ ERROR expected an `FnOnce(&bool)` closure, found `bool`
4	4	if number % 2 == 0 {
5	5	number == 0
6	6	} else {

tests/ui/expr/malformed_closure/block_instead_of_closure_in_arg.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnOnce(&bool)` closure, found `bool`
	1	error[E0277]: expected an `FnOnce(&bool)` closure, found `bool`
2	2	--> $DIR/block_instead_of_closure_in_arg.rs:3:23
3	3	\|
4	4	LL \| Some(true).filter({

tests/ui/expr/malformed_closure/ruby_style_closure_successful_parse.rs+1-1

...	...	@@ -1,6 +1,6 @@
1	1	const x: usize =42;
2	2	fn main() {
3		let p = Some(45).and_then({\|x\| //~ ERROR expected a `FnOnce({integer})` closure, found `Option<usize>`
	3	let p = Some(45).and_then({\|x\| //~ ERROR expected an `FnOnce({integer})` closure, found `Option<usize>`
4	4	1 + 1;
5	5	Some(x * 2)
6	6	});

tests/ui/expr/malformed_closure/ruby_style_closure_successful_parse.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnOnce({integer})` closure, found `Option<usize>`
	1	error[E0277]: expected an `FnOnce({integer})` closure, found `Option<usize>`
2	2	--> $DIR/ruby_style_closure_successful_parse.rs:3:31
3	3	\|
4	4	LL \| let p = Some(45).and_then({\|x\|

tests/ui/extern/extern-wrong-value-type.rs+1-1

...	...	@@ -7,5 +7,5 @@ fn main() {
7	7	// extern functions are extern "C" fn
8	8	let _x: extern "C" fn() = f; // OK
9	9	is_fn(f);
10		//~^ ERROR expected a `Fn()` closure, found `extern "C" fn() {f}`
	10	//~^ ERROR expected an `Fn()` closure, found `extern "C" fn() {f}`
11	11	}

tests/ui/extern/extern-wrong-value-type.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn()` closure, found `extern "C" fn() {f}`
	1	error[E0277]: expected an `Fn()` closure, found `extern "C" fn() {f}`
2	2	--> $DIR/extern-wrong-value-type.rs:9:11
3	3	\|
4	4	LL \| is_fn(f);

tests/ui/feature-gates/feature-gate-unboxed-closures-manual-impls.rs+2-2

...	...	@@ -9,7 +9,7 @@ struct Foo;
9	9	impl Fn<()> for Foo {
10	10	//~^ ERROR the precise format of `Fn`-family traits' type parameters is subject to change
11	11	//~\| ERROR manual implementations of `Fn` are experimental
12		//~\| ERROR expected a `FnMut()` closure, found `Foo`
	12	//~\| ERROR expected an `FnMut()` closure, found `Foo`
13	13	extern "rust-call" fn call(self, args: ()) -> () {}
14	14	//~^ ERROR "rust-call" ABI is experimental and subject to change
15	15	//~\| ERROR `call` has an incompatible type for trait
...	...	@@ -26,7 +26,7 @@ struct Bar;
26	26	impl FnMut<()> for Bar {
27	27	//~^ ERROR the precise format of `Fn`-family traits' type parameters is subject to change
28	28	//~\| ERROR manual implementations of `FnMut` are experimental
29		//~\| ERROR expected a `FnOnce()` closure, found `Bar`
	29	//~\| ERROR expected an `FnOnce()` closure, found `Bar`
30	30	extern "rust-call" fn call_mut(&self, args: ()) -> () {}
31	31	//~^ ERROR "rust-call" ABI is experimental and subject to change
32	32	//~\| ERROR incompatible type for trait

tests/ui/feature-gates/feature-gate-unboxed-closures-manual-impls.stderr+2-2

...	...	@@ -87,7 +87,7 @@ LL \| impl FnMut<()> for Bar {
87	87	\|
88	88	= help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
89	89
90		error[E0277]: expected a `FnMut()` closure, found `Foo`
	90	error[E0277]: expected an `FnMut()` closure, found `Foo`
91	91	--> $DIR/feature-gate-unboxed-closures-manual-impls.rs:9:17
92	92	\|
93	93	LL \| impl Fn<()> for Foo {
...	...	@@ -161,7 +161,7 @@ help: change the self-receiver type to match the trait
161	161	LL \| extern "rust-call" fn call_mut(&mut self, args: ()) -> () {}
162	162	\| +++
163	163
164		error[E0277]: expected a `FnOnce()` closure, found `Bar`
	164	error[E0277]: expected an `FnOnce()` closure, found `Bar`
165	165	--> $DIR/feature-gate-unboxed-closures-manual-impls.rs:26:20
166	166	\|
167	167	LL \| impl FnMut<()> for Bar {

tests/ui/fn/fn-trait-formatting.rs+1-1

...	...	@@ -17,5 +17,5 @@ fn main() {
17	17	//~\| NOTE found struct `Box<dyn FnMut() -> isize>`
18	18
19	19	needs_fn(1);
20		//~^ ERROR expected a `Fn(isize)` closure, found `{integer}`
	20	//~^ ERROR expected an `Fn(isize)` closure, found `{integer}`
21	21	}

tests/ui/fn/fn-trait-formatting.stderr+1-1

...	...	@@ -39,7 +39,7 @@ LL \| let _: () = Box::new(\|\| -> isize { unimplemented!() }) as Box<dyn FnMut
39	39	= note: expected unit type `()`
40	40	found struct `Box<dyn FnMut() -> isize>`
41	41
42		error[E0277]: expected a `Fn(isize)` closure, found `{integer}`
	42	error[E0277]: expected an `Fn(isize)` closure, found `{integer}`
43	43	--> $DIR/fn-trait-formatting.rs:19:14
44	44	\|
45	45	LL \| needs_fn(1);

tests/ui/fn/issue-39259.rs+1-1

...	...	@@ -5,7 +5,7 @@ struct S;
5	5
6	6	impl Fn(u32) -> u32 for S {
7	7	//~^ ERROR associated item constraints are not allowed here [E0229]
8		//~\| ERROR expected a `FnMut(u32)` closure, found `S`
	8	//~\| ERROR expected an `FnMut(u32)` closure, found `S`
9	9	fn call(&self) -> u32 {
10	10	//~^ ERROR method `call` has 1 parameter but the declaration in trait `call` has 2
11	11	5

tests/ui/fn/issue-39259.stderr+1-1

...	...	@@ -22,7 +22,7 @@ help: add the missing parameter from the trait
22	22	LL \| fn call(&self, args: Args) -> u32 {
23	23	\| ++++++++++++
24	24
25		error[E0277]: expected a `FnMut(u32)` closure, found `S`
	25	error[E0277]: expected an `FnMut(u32)` closure, found `S`
26	26	--> $DIR/issue-39259.rs:6:25
27	27	\|
28	28	LL \| impl Fn(u32) -> u32 for S {

tests/ui/generic-associated-types/issue-68642-broken-llvm-ir.rs+1-1

...	...	@@ -10,7 +10,7 @@ trait Fun {
10	10
11	11	impl<T> Fun for T {
12	12	type F<'a> = Self;
13		//~^ ERROR expected a `Fn()` closure, found `T`
	13	//~^ ERROR expected an `Fn()` closure, found `T`
14	14	}
15	15
16	16	fn main() {

tests/ui/generic-associated-types/issue-68642-broken-llvm-ir.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn()` closure, found `T`
	1	error[E0277]: expected an `Fn()` closure, found `T`
2	2	--> $DIR/issue-68642-broken-llvm-ir.rs:12:18
3	3	\|
4	4	LL \| type F<'a> = Self;

tests/ui/generic-associated-types/issue-68643-broken-mir.rs+1-1

...	...	@@ -10,7 +10,7 @@ trait Fun {
10	10
11	11	impl<T> Fun for T {
12	12	type F<'a> = Self;
13		//~^ ERROR expected a `Fn()` closure, found `T`
	13	//~^ ERROR expected an `Fn()` closure, found `T`
14	14	}
15	15
16	16	pub fn main() {

tests/ui/generic-associated-types/issue-68643-broken-mir.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn()` closure, found `T`
	1	error[E0277]: expected an `Fn()` closure, found `T`
2	2	--> $DIR/issue-68643-broken-mir.rs:12:18
3	3	\|
4	4	LL \| type F<'a> = Self;

tests/ui/generic-associated-types/issue-68644-codegen-selection.rs+1-1

...	...	@@ -10,7 +10,7 @@ trait Fun {
10	10
11	11	impl<T> Fun for T {
12	12	type F<'a> = Self;
13		//~^ ERROR expected a `Fn()` closure, found `T`
	13	//~^ ERROR expected an `Fn()` closure, found `T`
14	14	}
15	15
16	16	fn main() {

tests/ui/generic-associated-types/issue-68644-codegen-selection.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn()` closure, found `T`
	1	error[E0277]: expected an `Fn()` closure, found `T`
2	2	--> $DIR/issue-68644-codegen-selection.rs:12:18
3	3	\|
4	4	LL \| type F<'a> = Self;

tests/ui/generic-associated-types/issue-68645-codegen-fulfillment.rs+1-1

...	...	@@ -10,7 +10,7 @@ trait Fun {
10	10
11	11	impl<T> Fun for T {
12	12	type F<'a> = Self;
13		//~^ ERROR expected a `Fn()` closure, found `T`
	13	//~^ ERROR expected an `Fn()` closure, found `T`
14	14	}
15	15
16	16	fn main() {

tests/ui/generic-associated-types/issue-68645-codegen-fulfillment.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn()` closure, found `T`
	1	error[E0277]: expected an `Fn()` closure, found `T`
2	2	--> $DIR/issue-68645-codegen-fulfillment.rs:12:18
3	3	\|
4	4	LL \| type F<'a> = Self;

tests/ui/higher-ranked/trait-bounds/normalize-under-binder/issue-62529-3.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn(<_ as ATC<'a>>::Type)` closure, found `F`
	1	error[E0277]: expected an `Fn(<_ as ATC<'a>>::Type)` closure, found `F`
2	2	--> $DIR/issue-62529-3.rs:25:14
3	3	\|
4	4	LL \| call(f, ());

tests/ui/implied-bounds/issue-100690.rs+1-1

...	...	@@ -32,7 +32,7 @@ impl<'a, T: 'a> Handle<'a, T, UIView<'a, T>, Result<(), io::Error>> for TUIHandl
32	32	F: FnOnce(&mut UIView<'a, T>) -> Result<(), io::Error> + Send + 'static,
33	33	{
34	34	real_dispatch(f)
35		//~^ ERROR expected a `FnOnce(&mut UIView<'_, T>)` closure, found `F`
	35	//~^ ERROR expected an `FnOnce(&mut UIView<'_, T>)` closure, found `F`
36	36	}
37	37	}
38	38

tests/ui/implied-bounds/issue-100690.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnOnce(&mut UIView<'_, T>)` closure, found `F`
	1	error[E0277]: expected an `FnOnce(&mut UIView<'_, T>)` closure, found `F`
2	2	--> $DIR/issue-100690.rs:34:23
3	3	\|
4	4	LL \| real_dispatch(f)

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

...	...	@@ -7,8 +7,8 @@ const fn not_fn_items() {
7	7	const_eval_select((), \|\| {}, \|\| {});
8	8	//~^ ERROR const FnOnce()` is not satisfied
9	9	const_eval_select((), 42, 0xDEADBEEF);
10		//~^ ERROR expected a `FnOnce()` closure
11		//~\| ERROR expected a `FnOnce()` closure
	10	//~^ ERROR expected an `FnOnce()` closure
	11	//~\| ERROR expected an `FnOnce()` closure
12	12	}
13	13
14	14	const fn foo(n: i32) -> i32 {

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

...	...	@@ -9,7 +9,7 @@ LL \| const_eval_select((), \|\| {}, \|\| {});
9	9	note: required by a bound in `const_eval_select`
10	10	--> $SRC_DIR/core/src/intrinsics/mod.rs:LL:COL
11	11
12		error[E0277]: expected a `FnOnce()` closure, found `{integer}`
	12	error[E0277]: expected an `FnOnce()` closure, found `{integer}`
13	13	--> $DIR/const-eval-select-bad.rs:9:27
14	14	\|
15	15	LL \| const_eval_select((), 42, 0xDEADBEEF);
...	...	@@ -22,7 +22,7 @@ LL \| const_eval_select((), 42, 0xDEADBEEF);
22	22	note: required by a bound in `const_eval_select`
23	23	--> $SRC_DIR/core/src/intrinsics/mod.rs:LL:COL
24	24
25		error[E0277]: expected a `FnOnce()` closure, found `{integer}`
	25	error[E0277]: expected an `FnOnce()` closure, found `{integer}`
26	26	--> $DIR/const-eval-select-bad.rs:9:31
27	27	\|
28	28	LL \| const_eval_select((), 42, 0xDEADBEEF);

tests/ui/iterators/fold-iterator-error-23966.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnMut(_, char)` closure, found `()`
	1	error[E0277]: expected an `FnMut(_, char)` closure, found `()`
2	2	--> $DIR/fold-iterator-error-23966.rs:3:32
3	3	\|
4	4	LL \| "".chars().fold(\|_, _\| (), ());

tests/ui/lifetimes/issue-76168-hr-outlives-3.rs+3-3

...	...	@@ -4,9 +4,9 @@
4	4	use std::future::Future;
5	5
6	6	async fn wrapper<F>(f: F)
7		//~^ ERROR: expected a `FnOnce(&'a mut i32)` closure, found `i32`
8		//~\| ERROR: expected a `FnOnce(&'a mut i32)` closure, found `i32`
9		//~\| ERROR: expected a `FnOnce(&'a mut i32)` closure, found `i32`
	7	//~^ ERROR: expected an `FnOnce(&'a mut i32)` closure, found `i32`
	8	//~\| ERROR: expected an `FnOnce(&'a mut i32)` closure, found `i32`
	9	//~\| ERROR: expected an `FnOnce(&'a mut i32)` closure, found `i32`
10	10	where
11	11	F:,
12	12	for<'a> <i32 as FnOnce<(&'a mut i32,)>>::Output: Future<Output = ()> + 'a,

tests/ui/lifetimes/issue-76168-hr-outlives-3.stderr+3-3

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnOnce(&'a mut i32)` closure, found `i32`
	1	error[E0277]: expected an `FnOnce(&'a mut i32)` closure, found `i32`
2	2	--> $DIR/issue-76168-hr-outlives-3.rs:6:1
3	3	\|
4	4	LL \| / async fn wrapper<F>(f: F)
...	...	@@ -9,7 +9,7 @@ LL \| \| for<'a> <i32 as FnOnce<(&'a mut i32,)>>::Output: Future<Output = ()>
9	9	\|
10	10	= help: the trait `for<'a> FnOnce(&'a mut i32)` is not implemented for `i32`
11	11
12		error[E0277]: expected a `FnOnce(&'a mut i32)` closure, found `i32`
	12	error[E0277]: expected an `FnOnce(&'a mut i32)` closure, found `i32`
13	13	--> $DIR/issue-76168-hr-outlives-3.rs:6:26
14	14	\|
15	15	LL \| async fn wrapper<F>(f: F)
...	...	@@ -17,7 +17,7 @@ LL \| async fn wrapper<F>(f: F)
17	17	\|
18	18	= help: the trait `for<'a> FnOnce(&'a mut i32)` is not implemented for `i32`
19	19
20		error[E0277]: expected a `FnOnce(&'a mut i32)` closure, found `i32`
	20	error[E0277]: expected an `FnOnce(&'a mut i32)` closure, found `i32`
21	21	--> $DIR/issue-76168-hr-outlives-3.rs:6:26
22	22	\|
23	23	LL \| async fn wrapper<F>(f: F)

tests/ui/lifetimes/issue-95023.rs+1-1

...	...	@@ -4,7 +4,7 @@ impl Fn(&isize) for Error {
4	4	//~^ ERROR manual implementations of `Fn` are experimental [E0183]
5	5	//~\| ERROR associated item constraints are not allowed here [E0229]
6	6	//~\| ERROR not all trait items implemented
7		//~\| ERROR expected a `FnMut(&isize)` closure, found `Error`
	7	//~\| ERROR expected an `FnMut(&isize)` closure, found `Error`
8	8	fn foo<const N: usize>(&self) -> Self::B<{ N }>;
9	9	//~^ ERROR associated function in `impl` without body
10	10	//~\| ERROR method `foo` is not a member of trait `Fn` [E0407]

tests/ui/lifetimes/issue-95023.stderr+1-1

...	...	@@ -40,7 +40,7 @@ LL \| impl Fn(&isize) for Error {
40	40	\|
41	41	= help: implement the missing item: `fn call(&self, _: (&isize,)) -> <Self as FnOnce<(&isize,)>>::Output { todo!() }`
42	42
43		error[E0277]: expected a `FnMut(&isize)` closure, found `Error`
	43	error[E0277]: expected an `FnMut(&isize)` closure, found `Error`
44	44	--> $DIR/issue-95023.rs:3:21
45	45	\|
46	46	LL \| impl Fn(&isize) for Error {

tests/ui/macros/ice-in-tokenstream-for-contracts-issue-140683.rs+1-1

...	...	@@ -4,7 +4,7 @@
4	4	struct T;
5	5
6	6	impl T {
7		#[core::contracts::ensures] //~ ERROR expected a `Fn(&_)` closure, found `()`
	7	#[core::contracts::ensures] //~ ERROR expected an `Fn(&_)` closure, found `()`
8	8	fn b() {(loop)}
9	9	//~^ ERROR expected `{`, found `)`
10	10	//~\| ERROR expected `{`, found `)`

tests/ui/macros/ice-in-tokenstream-for-contracts-issue-140683.stderr+1-1

...	...	@@ -16,7 +16,7 @@ LL \| fn b() {(loop)}
16	16	\|
17	17	= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
18	18
19		error[E0277]: expected a `Fn(&_)` closure, found `()`
	19	error[E0277]: expected an `Fn(&_)` closure, found `()`
20	20	--> $DIR/ice-in-tokenstream-for-contracts-issue-140683.rs:7:5
21	21	\|
22	22	LL \| #[core::contracts::ensures]

tests/ui/methods/filter-relevant-fn-bounds.rs+1-1

...	...	@@ -16,5 +16,5 @@ impl Wrapper {
16	16	fn main() {
17	17	let mut wrapper = Wrapper;
18	18	wrapper.do_something_wrapper(\|value\| ());
19		//~^ ERROR expected a `FnOnce
	19	//~^ ERROR expected an `FnOnce
20	20	}

tests/ui/methods/filter-relevant-fn-bounds.stderr+1-1

...	...	@@ -12,7 +12,7 @@ help: consider further restricting type parameter `F` with trait `Output`
12	12	LL \| F: for<'a> FnOnce(<F as Output<'a>>::Type) + for<'a> Output<'a>,
13	13	\| ++++++++++++++++++++
14	14
15		error[E0277]: expected a `FnOnce(<{closure@$DIR/filter-relevant-fn-bounds.rs:18:34: 18:41} as Output<'a>>::Type)` closure, found `{closure@$DIR/filter-relevant-fn-bounds.rs:18:34: 18:41}`
	15	error[E0277]: expected an `FnOnce(<{closure@$DIR/filter-relevant-fn-bounds.rs:18:34: 18:41} as Output<'a>>::Type)` closure, found `{closure@$DIR/filter-relevant-fn-bounds.rs:18:34: 18:41}`
16	16	--> $DIR/filter-relevant-fn-bounds.rs:18:34
17	17	\|
18	18	LL \| wrapper.do_something_wrapper(\|value\| ());

tests/ui/methods/method-suggestion-trait-with-extra-generics-no-ice.rs+1-1

...	...	@@ -16,7 +16,7 @@ struct Bar;
16	16
17	17	fn main() {
18	18	let foo: Box<dyn Fn(bool) -> usize> = Box::new(Bar);
19		//~^ ERROR expected a `Fn(bool)` closure, found `Bar`
	19	//~^ ERROR expected an `Fn(bool)` closure, found `Bar`
20	20	foo.borrow();
21	21	//~^ ERROR no method named `borrow` found
22	22	foo.take()

tests/ui/methods/method-suggestion-trait-with-extra-generics-no-ice.stderr+1-1

...	...	@@ -22,7 +22,7 @@ help: there is a method `borrow_mut` with a similar name
22	22	LL \| foo.borrow_mut();
23	23	\| ++++
24	24
25		error[E0277]: expected a `Fn(bool)` closure, found `Bar`
	25	error[E0277]: expected an `Fn(bool)` closure, found `Bar`
26	26	--> $DIR/method-suggestion-trait-with-extra-generics-no-ice.rs:18:43
27	27	\|
28	28	LL \| let foo: Box<dyn Fn(bool) -> usize> = Box::new(Bar);

tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.current.fixed+2-2

...	...	@@ -5,10 +5,10 @@
5	5	fn main() {
6	6	let _ = (-10..=10).find(\|x: &i32\| x.signum() == 0);
7	7	//[current]~^ ERROR type mismatch in closure arguments
8		//[next]~^^ ERROR: expected a `FnMut(&{integer})` closure, found
	8	//[next]~^^ ERROR: expected an `FnMut(&{integer})` closure, found
9	9	//[next]~\| ERROR: type mismatch resolving `<{closure@closure-arg-type-mismatch-issue-45727.rs:6:29} as FnOnce<(&{integer},)>>::Output == bool`
10	10	let _ = (-10..=10).find(\|x: &i32\| x.signum() == 0);
11	11	//[current]~^ ERROR type mismatch in closure arguments
12		//[next]~^^ ERROR: expected a `FnMut(&{integer})` closure, found
	12	//[next]~^^ ERROR: expected an `FnMut(&{integer})` closure, found
13	13	//[next]~\| ERROR: type mismatch resolving `<{closure@closure-arg-type-mismatch-issue-45727.rs:10:29} as FnOnce<(&{integer},)>>::Output == bool`
14	14	}

tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.next.stderr+2-2

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnMut(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:6:29: 6:37}`
	1	error[E0277]: expected an `FnMut(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:6:29: 6:37}`
2	2	--> $DIR/closure-arg-type-mismatch-issue-45727.rs:6:29
3	3	\|
4	4	LL \| let _ = (-10..=10).find(\|x: i32\| x.signum() == 0);
...	...	@@ -23,7 +23,7 @@ LL \| let _ = (-10..=10).find(\|x: i32\| x.signum() == 0);
23	23	note: required by a bound in `find`
24	24	--> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
25	25
26		error[E0277]: expected a `FnMut(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
	26	error[E0277]: expected an `FnMut(&{integer})` closure, found `{closure@$DIR/closure-arg-type-mismatch-issue-45727.rs:10:29: 10:40}`
27	27	--> $DIR/closure-arg-type-mismatch-issue-45727.rs:10:29
28	28	\|
29	29	LL \| let _ = (-10..=10).find(\|x: &&&i32\| x.signum() == 0);

tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.rs+2-2

...	...	@@ -5,10 +5,10 @@
5	5	fn main() {
6	6	let _ = (-10..=10).find(\|x: i32\| x.signum() == 0);
7	7	//[current]~^ ERROR type mismatch in closure arguments
8		//[next]~^^ ERROR: expected a `FnMut(&{integer})` closure, found
	8	//[next]~^^ ERROR: expected an `FnMut(&{integer})` closure, found
9	9	//[next]~\| ERROR: type mismatch resolving `<{closure@closure-arg-type-mismatch-issue-45727.rs:6:29} as FnOnce<(&{integer},)>>::Output == bool`
10	10	let _ = (-10..=10).find(\|x: &&&i32\| x.signum() == 0);
11	11	//[current]~^ ERROR type mismatch in closure arguments
12		//[next]~^^ ERROR: expected a `FnMut(&{integer})` closure, found
	12	//[next]~^^ ERROR: expected an `FnMut(&{integer})` closure, found
13	13	//[next]~\| ERROR: type mismatch resolving `<{closure@closure-arg-type-mismatch-issue-45727.rs:10:29} as FnOnce<(&{integer},)>>::Output == bool`
14	14	}

tests/ui/mismatched_types/suggest-option-asderef-unfixable.rs+2-2

...	...	@@ -24,9 +24,9 @@ fn main() {
24	24	let _ = produces_string().and_then(takes_str_but_too_many_refs);
25	25	//~^ ERROR type mismatch in function arguments
26	26	let _ = produces_string().and_then(takes_str_but_wrong_abi);
27		//~^ ERROR expected a `FnOnce(String)` closure, found `for<'a> extern "C" fn(&'a str) -> Option<()> {takes_str_but_wrong_abi}`
	27	//~^ ERROR expected an `FnOnce(String)` closure, found `for<'a> extern "C" fn(&'a str) -> Option<()> {takes_str_but_wrong_abi}`
28	28	let _ = produces_string().and_then(takes_str_but_unsafe);
29		//~^ ERROR expected a `FnOnce(String)` closure, found `for<'a> unsafe fn(&'a str) -> Option<()> {takes_str_but_unsafe}`
	29	//~^ ERROR expected an `FnOnce(String)` closure, found `for<'a> unsafe fn(&'a str) -> Option<()> {takes_str_but_unsafe}`
30	30	let _ = produces_string().and_then(no_args);
31	31	//~^ ERROR function is expected to take 1 argument, but it takes 0 arguments
32	32	let _ = Some(TypeWithoutDeref).and_then(takes_str_but_too_many_refs);

tests/ui/mismatched_types/suggest-option-asderef-unfixable.stderr+2-2

...	...	@@ -18,7 +18,7 @@ help: consider wrapping the function in a closure
18	18	LL \| let _ = produces_string().and_then(\|arg0: String\| takes_str_but_too_many_refs(/* &&str */));
19	19	\| ++++++++++++++ +++++++++++++
20	20
21		error[E0277]: expected a `FnOnce(String)` closure, found `for<'a> extern "C" fn(&'a str) -> Option<()> {takes_str_but_wrong_abi}`
	21	error[E0277]: expected an `FnOnce(String)` closure, found `for<'a> extern "C" fn(&'a str) -> Option<()> {takes_str_but_wrong_abi}`
22	22	--> $DIR/suggest-option-asderef-unfixable.rs:26:40
23	23	\|
24	24	LL \| let _ = produces_string().and_then(takes_str_but_wrong_abi);
...	...	@@ -30,7 +30,7 @@ LL \| let _ = produces_string().and_then(takes_str_but_wrong_abi);
30	30	note: required by a bound in `Option::<T>::and_then`
31	31	--> $SRC_DIR/core/src/option.rs:LL:COL
32	32
33		error[E0277]: expected a `FnOnce(String)` closure, found `for<'a> unsafe fn(&'a str) -> Option<()> {takes_str_but_unsafe}`
	33	error[E0277]: expected an `FnOnce(String)` closure, found `for<'a> unsafe fn(&'a str) -> Option<()> {takes_str_but_unsafe}`
34	34	--> $DIR/suggest-option-asderef-unfixable.rs:28:40
35	35	\|
36	36	LL \| let _ = produces_string().and_then(takes_str_but_unsafe);

tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.rs+7-7

...	...	@@ -26,15 +26,15 @@ fn call_once_i32(f: impl FnOnce(i32)) {
26	26	}
27	27
28	28	fn main() {
29		call(foo); //~ ERROR expected a `Fn()` closure, found `#[target_features] fn() {foo}`
30		call_mut(foo); //~ ERROR expected a `FnMut()` closure, found `#[target_features] fn() {foo}`
31		call_once(foo); //~ ERROR expected a `FnOnce()` closure, found `#[target_features] fn() {foo}`
32		call_once_i32(bar); //~ ERROR expected a `FnOnce(i32)` closure, found `#[target_features] fn(i32) {bar}`
	29	call(foo); //~ ERROR expected an `Fn()` closure, found `#[target_features] fn() {foo}`
	30	call_mut(foo); //~ ERROR expected an `FnMut()` closure, found `#[target_features] fn() {foo}`
	31	call_once(foo); //~ ERROR expected an `FnOnce()` closure, found `#[target_features] fn() {foo}`
	32	call_once_i32(bar); //~ ERROR expected an `FnOnce(i32)` closure, found `#[target_features] fn(i32) {bar}`
33	33
34	34	call(foo_unsafe);
35		//~^ ERROR expected a `Fn()` closure, found `unsafe fn() {foo_unsafe}`
	35	//~^ ERROR expected an `Fn()` closure, found `unsafe fn() {foo_unsafe}`
36	36	call_mut(foo_unsafe);
37		//~^ ERROR expected a `FnMut()` closure, found `unsafe fn() {foo_unsafe}`
	37	//~^ ERROR expected an `FnMut()` closure, found `unsafe fn() {foo_unsafe}`
38	38	call_once(foo_unsafe);
39		//~^ ERROR expected a `FnOnce()` closure, found `unsafe fn() {foo_unsafe}`
	39	//~^ ERROR expected an `FnOnce()` closure, found `unsafe fn() {foo_unsafe}`
40	40	}

tests/ui/rfcs/rfc-2396-target_feature-11/fn-traits.stderr+7-7

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn()` closure, found `#[target_features] fn() {foo}`
	1	error[E0277]: expected an `Fn()` closure, found `#[target_features] fn() {foo}`
2	2	--> $DIR/fn-traits.rs:29:10
3	3	\|
4	4	LL \| call(foo);
...	...	@@ -16,7 +16,7 @@ note: required by a bound in `call`
16	16	LL \| fn call(f: impl Fn()) {
17	17	\| ^^^^ required by this bound in `call`
18	18
19		error[E0277]: expected a `FnMut()` closure, found `#[target_features] fn() {foo}`
	19	error[E0277]: expected an `FnMut()` closure, found `#[target_features] fn() {foo}`
20	20	--> $DIR/fn-traits.rs:30:14
21	21	\|
22	22	LL \| call_mut(foo);
...	...	@@ -34,7 +34,7 @@ note: required by a bound in `call_mut`
34	34	LL \| fn call_mut(mut f: impl FnMut()) {
35	35	\| ^^^^^^^ required by this bound in `call_mut`
36	36
37		error[E0277]: expected a `FnOnce()` closure, found `#[target_features] fn() {foo}`
	37	error[E0277]: expected an `FnOnce()` closure, found `#[target_features] fn() {foo}`
38	38	--> $DIR/fn-traits.rs:31:15
39	39	\|
40	40	LL \| call_once(foo);
...	...	@@ -52,7 +52,7 @@ note: required by a bound in `call_once`
52	52	LL \| fn call_once(f: impl FnOnce()) {
53	53	\| ^^^^^^^^ required by this bound in `call_once`
54	54
55		error[E0277]: expected a `FnOnce(i32)` closure, found `#[target_features] fn(i32) {bar}`
	55	error[E0277]: expected an `FnOnce(i32)` closure, found `#[target_features] fn(i32) {bar}`
56	56	--> $DIR/fn-traits.rs:32:19
57	57	\|
58	58	LL \| call_once_i32(bar);
...	...	@@ -69,7 +69,7 @@ note: required by a bound in `call_once_i32`
69	69	LL \| fn call_once_i32(f: impl FnOnce(i32)) {
70	70	\| ^^^^^^^^^^^ required by this bound in `call_once_i32`
71	71
72		error[E0277]: expected a `Fn()` closure, found `unsafe fn() {foo_unsafe}`
	72	error[E0277]: expected an `Fn()` closure, found `unsafe fn() {foo_unsafe}`
73	73	--> $DIR/fn-traits.rs:34:10
74	74	\|
75	75	LL \| call(foo_unsafe);
...	...	@@ -88,7 +88,7 @@ note: required by a bound in `call`
88	88	LL \| fn call(f: impl Fn()) {
89	89	\| ^^^^ required by this bound in `call`
90	90
91		error[E0277]: expected a `FnMut()` closure, found `unsafe fn() {foo_unsafe}`
	91	error[E0277]: expected an `FnMut()` closure, found `unsafe fn() {foo_unsafe}`
92	92	--> $DIR/fn-traits.rs:36:14
93	93	\|
94	94	LL \| call_mut(foo_unsafe);
...	...	@@ -107,7 +107,7 @@ note: required by a bound in `call_mut`
107	107	LL \| fn call_mut(mut f: impl FnMut()) {
108	108	\| ^^^^^^^ required by this bound in `call_mut`
109	109
110		error[E0277]: expected a `FnOnce()` closure, found `unsafe fn() {foo_unsafe}`
	110	error[E0277]: expected an `FnOnce()` closure, found `unsafe fn() {foo_unsafe}`
111	111	--> $DIR/fn-traits.rs:38:15
112	112	\|
113	113	LL \| call_once(foo_unsafe);

tests/ui/suggestions/restrict-bound-already-has-generic-args.rs created+27

...	...	@@ -0,0 +1,27 @@
	1	// Regression test for https://github.com/rust-lang/rust/issues/142803.
	2
	3	trait Pair {
	4	type Left;
	5	type Right;
	6
	7	fn split(self) -> (Self::Left, Self::Right);
	8	}
	9
	10	impl<A, B> Pair for (A, B) {
	11	type Left = A;
	12	type Right = B;
	13
	14	fn split(self) -> (Self::Left, Self::Right) {
	15	self
	16	}
	17	}
	18
	19	fn frob<A, B>(pair: impl Pair<Left = A>) -> impl Pair<Left = A, Right = B> {
	20	//~^ ERROR type mismatch
	21	//~\| HELP consider further restricting this bound
	22	//~\| SUGGESTION , Right = B
	23	let (left, right) = pair.split();
	24	(left, right)
	25	}
	26
	27	fn main() {}

tests/ui/suggestions/restrict-bound-already-has-generic-args.stderr created+24

...	...	@@ -0,0 +1,24 @@
	1	error[E0271]: type mismatch resolving `<(A, <impl Pair<Left = A> as Pair>::Right) as Pair>::Right == B`
	2	--> $DIR/restrict-bound-already-has-generic-args.rs:19:45
	3	\|
	4	LL \| fn frob<A, B>(pair: impl Pair<Left = A>) -> impl Pair<Left = A, Right = B> {
	5	\| - expected this type parameter ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type mismatch resolving `<(A, <impl Pair<Left = A> as Pair>::Right) as Pair>::Right == B`
	6	...
	7	LL \| (left, right)
	8	\| ------------- return type was inferred to be `(A, <impl Pair<Left = A> as Pair>::Right)` here
	9	\|
	10	note: expected this to be `B`
	11	--> $DIR/restrict-bound-already-has-generic-args.rs:12:18
	12	\|
	13	LL \| type Right = B;
	14	\| ^
	15	= note: expected type parameter `B`
	16	found associated type `<impl Pair<Left = A> as Pair>::Right`
	17	help: consider further restricting this bound
	18	\|
	19	LL \| fn frob<A, B>(pair: impl Pair<Left = A, Right = B>) -> impl Pair<Left = A, Right = B> {
	20	\| +++++++++++
	21
	22	error: aborting due to 1 previous error
	23
	24	For more information about this error, try `rustc --explain E0271`.

tests/ui/trait-bounds/mismatch-fn-trait.stderr+5-5

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnMut(i32)` closure, found `impl FnMut(u32)`
	1	error[E0277]: expected an `FnMut(i32)` closure, found `impl FnMut(u32)`
2	2	--> $DIR/mismatch-fn-trait.rs:4:10
3	3	\|
4	4	LL \| take(f)
...	...	@@ -14,7 +14,7 @@ note: required by a bound in `take`
14	14	LL \| fn take(_f: impl FnMut(i32)) {}
15	15	\| ^^^^^^^^^^ required by this bound in `take`
16	16
17		error[E0277]: expected a `FnMut(i32)` closure, found `impl FnMut(i32, i32)`
	17	error[E0277]: expected an `FnMut(i32)` closure, found `impl FnMut(i32, i32)`
18	18	--> $DIR/mismatch-fn-trait.rs:9:10
19	19	\|
20	20	LL \| take(f)
...	...	@@ -29,7 +29,7 @@ note: required by a bound in `take`
29	29	LL \| fn take(_f: impl FnMut(i32)) {}
30	30	\| ^^^^^^^^^^ required by this bound in `take`
31	31
32		error[E0277]: expected a `FnMut(i32)` closure, found `impl FnMut()`
	32	error[E0277]: expected an `FnMut(i32)` closure, found `impl FnMut()`
33	33	--> $DIR/mismatch-fn-trait.rs:14:10
34	34	\|
35	35	LL \| take(f)
...	...	@@ -44,7 +44,7 @@ note: required by a bound in `take`
44	44	LL \| fn take(_f: impl FnMut(i32)) {}
45	45	\| ^^^^^^^^^^ required by this bound in `take`
46	46
47		error[E0277]: expected a `FnMut(i32)` closure, found `impl FnOnce(i32)`
	47	error[E0277]: expected an `FnMut(i32)` closure, found `impl FnOnce(i32)`
48	48	--> $DIR/mismatch-fn-trait.rs:19:10
49	49	\|
50	50	LL \| take(f)
...	...	@@ -59,7 +59,7 @@ note: required by a bound in `take`
59	59	LL \| fn take(_f: impl FnMut(i32)) {}
60	60	\| ^^^^^^^^^^ required by this bound in `take`
61	61
62		error[E0277]: expected a `FnMut(i32)` closure, found `impl FnOnce(u32)`
	62	error[E0277]: expected an `FnMut(i32)` closure, found `impl FnOnce(u32)`
63	63	--> $DIR/mismatch-fn-trait.rs:24:10
64	64	\|
65	65	LL \| take(f)

tests/ui/traits/associated_type_bound/check-trait-object-bounds-2.rs+1-1

...	...	@@ -11,5 +11,5 @@ fn f<T: for<'r> X<'r> + ?Sized>() {
11	11
12	12	fn main() {
13	13	f::<dyn for<'x> X<'x, F = i32>>();
14		//~^ ERROR expected a `FnOnce(&i32)` closure, found `i32`
	14	//~^ ERROR expected an `FnOnce(&i32)` closure, found `i32`
15	15	}

tests/ui/traits/associated_type_bound/check-trait-object-bounds-2.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnOnce(&i32)` closure, found `i32`
	1	error[E0277]: expected an `FnOnce(&i32)` closure, found `i32`
2	2	--> $DIR/check-trait-object-bounds-2.rs:13:9
3	3	\|
4	4	LL \| f::<dyn for<'x> X<'x, F = i32>>();

tests/ui/traits/issue-87558.stderr+1-1

...	...	@@ -32,7 +32,7 @@ LL \| impl Fn(&isize) for Error {
32	32	\|
33	33	= help: implement the missing item: `fn call(&self, _: (&isize,)) -> <Self as FnOnce<(&isize,)>>::Output { todo!() }`
34	34
35		error[E0277]: expected a `FnMut(&isize)` closure, found `Error`
	35	error[E0277]: expected an `FnMut(&isize)` closure, found `Error`
36	36	--> $DIR/issue-87558.rs:3:21
37	37	\|
38	38	LL \| impl Fn(&isize) for Error {

tests/ui/traits/next-solver/diagnostics/const-host-effect-hrtb-no-ice.rs+1-1

...	...	@@ -7,7 +7,7 @@ const fn with_positive<F: for<'a> [const] Fn(&'a ())>() {}
7	7
8	8	const _: () = {
9	9	with_positive::<()>();
10		//~^ ERROR expected a `Fn(&'a ())` closure, found `()`
	10	//~^ ERROR expected an `Fn(&'a ())` closure, found `()`
11	11	//~\| ERROR type mismatch resolving `<() as FnOnce<(&(),)>>::Output == ()`
12	12	};
13	13

tests/ui/traits/next-solver/diagnostics/const-host-effect-hrtb-no-ice.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn(&'a ())` closure, found `()`
	1	error[E0277]: expected an `Fn(&'a ())` closure, found `()`
2	2	--> $DIR/const-host-effect-hrtb-no-ice.rs:9:21
3	3	\|
4	4	LL \| with_positive::<()>();

tests/ui/traits/next-solver/fn-trait.rs+4-4

...	...	@@ -18,11 +18,11 @@ fn main() {
18	18	require_fn(f);
19	19	require_fn(f as fn() -> i32);
20	20	require_fn(f as unsafe fn() -> i32);
21		//~^ ERROR: expected a `Fn()` closure, found `unsafe fn() -> i32`
	21	//~^ ERROR: expected an `Fn()` closure, found `unsafe fn() -> i32`
22	22	require_fn(g);
23		//~^ ERROR: expected a `Fn()` closure, found `extern "C" fn() -> i32 {g}`
	23	//~^ ERROR: expected an `Fn()` closure, found `extern "C" fn() -> i32 {g}`
24	24	require_fn(g as extern "C" fn() -> i32);
25		//~^ ERROR: expected a `Fn()` closure, found `extern "C" fn() -> i32`
	25	//~^ ERROR: expected an `Fn()` closure, found `extern "C" fn() -> i32`
26	26	require_fn(h);
27		//~^ ERROR: expected a `Fn()` closure, found `unsafe fn() -> i32 {h}`
	27	//~^ ERROR: expected an `Fn()` closure, found `unsafe fn() -> i32 {h}`
28	28	}

tests/ui/traits/next-solver/fn-trait.stderr+4-4

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn()` closure, found `unsafe fn() -> i32`
	1	error[E0277]: expected an `Fn()` closure, found `unsafe fn() -> i32`
2	2	--> $DIR/fn-trait.rs:20:16
3	3	\|
4	4	LL \| require_fn(f as unsafe fn() -> i32);
...	...	@@ -15,7 +15,7 @@ note: required by a bound in `require_fn`
15	15	LL \| fn require_fn(_: impl Fn() -> i32) {}
16	16	\| ^^^^^^^^^^^ required by this bound in `require_fn`
17	17
18		error[E0277]: expected a `Fn()` closure, found `extern "C" fn() -> i32 {g}`
	18	error[E0277]: expected an `Fn()` closure, found `extern "C" fn() -> i32 {g}`
19	19	--> $DIR/fn-trait.rs:22:16
20	20	\|
21	21	LL \| require_fn(g);
...	...	@@ -31,7 +31,7 @@ note: required by a bound in `require_fn`
31	31	LL \| fn require_fn(_: impl Fn() -> i32) {}
32	32	\| ^^^^^^^^^^^ required by this bound in `require_fn`
33	33
34		error[E0277]: expected a `Fn()` closure, found `extern "C" fn() -> i32`
	34	error[E0277]: expected an `Fn()` closure, found `extern "C" fn() -> i32`
35	35	--> $DIR/fn-trait.rs:24:16
36	36	\|
37	37	LL \| require_fn(g as extern "C" fn() -> i32);
...	...	@@ -47,7 +47,7 @@ note: required by a bound in `require_fn`
47	47	LL \| fn require_fn(_: impl Fn() -> i32) {}
48	48	\| ^^^^^^^^^^^ required by this bound in `require_fn`
49	49
50		error[E0277]: expected a `Fn()` closure, found `unsafe fn() -> i32 {h}`
	50	error[E0277]: expected an `Fn()` closure, found `unsafe fn() -> i32 {h}`
51	51	--> $DIR/fn-trait.rs:26:16
52	52	\|
53	53	LL \| require_fn(h);

tests/ui/type-alias-impl-trait/issue-63279.rs+2-2

...	...	@@ -4,11 +4,11 @@ type Closure = impl FnOnce();
4	4
5	5	#[define_opaque(Closure)]
6	6	fn c() -> Closure {
7		//~^ ERROR: expected a `FnOnce()` closure, found `()`
	7	//~^ ERROR: expected an `FnOnce()` closure, found `()`
8	8	\|\| -> Closure { \|\| () }
9	9	//~^ ERROR: mismatched types
10	10	//~\| ERROR: mismatched types
11		//~\| ERROR: expected a `FnOnce()` closure, found `()`
	11	//~\| ERROR: expected an `FnOnce()` closure, found `()`
12	12	}
13	13
14	14	fn main() {}

tests/ui/type-alias-impl-trait/issue-63279.stderr+2-2

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `FnOnce()` closure, found `()`
	1	error[E0277]: expected an `FnOnce()` closure, found `()`
2	2	--> $DIR/issue-63279.rs:6:11
3	3	\|
4	4	LL \| fn c() -> Closure {
...	...	@@ -7,7 +7,7 @@ LL \| fn c() -> Closure {
7	7	= help: the trait `FnOnce()` is not implemented for `()`
8	8	= note: wrap the `()` in a closure with no arguments: `\|\| { /* code */ }`
9	9
10		error[E0277]: expected a `FnOnce()` closure, found `()`
	10	error[E0277]: expected an `FnOnce()` closure, found `()`
11	11	--> $DIR/issue-63279.rs:8:11
12	12	\|
13	13	LL \| \|\| -> Closure { \|\| () }

tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.rs+2-2

...	...	@@ -8,10 +8,10 @@ type Tait = impl FnOnce() -> ();
8	8
9	9	#[define_opaque(Tait)]
10	10	fn reify_as_tait() -> Thunk<Tait> {
11		//~^ ERROR: expected a `FnOnce()` closure, found `()`
	11	//~^ ERROR: expected an `FnOnce()` closure, found `()`
12	12	Thunk::new(\|cont\| cont)
13	13	//~^ ERROR: mismatched types
14		//~\| ERROR: expected a `FnOnce()` closure, found `()`
	14	//~\| ERROR: expected an `FnOnce()` closure, found `()`
15	15	}
16	16
17	17	struct Thunk<F>(F);

tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.stderr+2-2

...	...	@@ -10,7 +10,7 @@ LL \| Thunk::new(\|cont\| cont)
10	10	= note: expected struct `Thunk<_>`
11	11	found unit type `()`
12	12
13		error[E0277]: expected a `FnOnce()` closure, found `()`
	13	error[E0277]: expected an `FnOnce()` closure, found `()`
14	14	--> $DIR/lazy_subtyping_of_opaques.rs:12:23
15	15	\|
16	16	LL \| Thunk::new(\|cont\| cont)
...	...	@@ -19,7 +19,7 @@ LL \| Thunk::new(\|cont\| cont)
19	19	= help: the trait `FnOnce()` is not implemented for `()`
20	20	= note: wrap the `()` in a closure with no arguments: `\|\| { /* code */ }`
21	21
22		error[E0277]: expected a `FnOnce()` closure, found `()`
	22	error[E0277]: expected an `FnOnce()` closure, found `()`
23	23	--> $DIR/lazy_subtyping_of_opaques.rs:10:23
24	24	\|
25	25	LL \| fn reify_as_tait() -> Thunk<Tait> {

tests/ui/unboxed-closures/unboxed-closures-fnmut-as-fn.stderr+1-1

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn(isize)` closure, found `S`
	1	error[E0277]: expected an `Fn(isize)` closure, found `S`
2	2	--> $DIR/unboxed-closures-fnmut-as-fn.rs:27:21
3	3	\|
4	4	LL \| let x = call_it(&S, 22);

tests/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.stderr+3-3

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn(&isize)` closure, found `for<'a> unsafe fn(&'a isize) -> isize {square}`
	1	error[E0277]: expected an `Fn(&isize)` closure, found `for<'a> unsafe fn(&'a isize) -> isize {square}`
2	2	--> $DIR/unboxed-closures-unsafe-extern-fn.rs:20:21
3	3	\|
4	4	LL \| let x = call_it(&square, 22);
...	...	@@ -14,7 +14,7 @@ note: required by a bound in `call_it`
14	14	LL \| fn call_it<F: Fn(&isize) -> isize>(_: &F, _: isize) -> isize {
15	15	\| ^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it`
16	16
17		error[E0277]: expected a `FnMut(&isize)` closure, found `for<'a> unsafe fn(&'a isize) -> isize {square}`
	17	error[E0277]: expected an `FnMut(&isize)` closure, found `for<'a> unsafe fn(&'a isize) -> isize {square}`
18	18	--> $DIR/unboxed-closures-unsafe-extern-fn.rs:25:25
19	19	\|
20	20	LL \| let y = call_it_mut(&mut square, 22);
...	...	@@ -30,7 +30,7 @@ note: required by a bound in `call_it_mut`
30	30	LL \| fn call_it_mut<F: FnMut(&isize) -> isize>(_: &mut F, _: isize) -> isize {
31	31	\| ^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it_mut`
32	32
33		error[E0277]: expected a `FnOnce(&isize)` closure, found `for<'a> unsafe fn(&'a isize) -> isize {square}`
	33	error[E0277]: expected an `FnOnce(&isize)` closure, found `for<'a> unsafe fn(&'a isize) -> isize {square}`
34	34	--> $DIR/unboxed-closures-unsafe-extern-fn.rs:30:26
35	35	\|
36	36	LL \| let z = call_it_once(square, 22);

tests/ui/unboxed-closures/unboxed-closures-wrong-abi.stderr+3-3

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn(&isize)` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
	1	error[E0277]: expected an `Fn(&isize)` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
2	2	--> $DIR/unboxed-closures-wrong-abi.rs:20:21
3	3	\|
4	4	LL \| let x = call_it(&square, 22);
...	...	@@ -13,7 +13,7 @@ note: required by a bound in `call_it`
13	13	LL \| fn call_it<F: Fn(&isize) -> isize>(_: &F, _: isize) -> isize {
14	14	\| ^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it`
15	15
16		error[E0277]: expected a `FnMut(&isize)` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
	16	error[E0277]: expected an `FnMut(&isize)` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
17	17	--> $DIR/unboxed-closures-wrong-abi.rs:25:25
18	18	\|
19	19	LL \| let y = call_it_mut(&mut square, 22);
...	...	@@ -28,7 +28,7 @@ note: required by a bound in `call_it_mut`
28	28	LL \| fn call_it_mut<F: FnMut(&isize) -> isize>(_: &mut F, _: isize) -> isize {
29	29	\| ^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it_mut`
30	30
31		error[E0277]: expected a `FnOnce(&isize)` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
	31	error[E0277]: expected an `FnOnce(&isize)` closure, found `for<'a> extern "C" fn(&'a isize) -> isize {square}`
32	32	--> $DIR/unboxed-closures-wrong-abi.rs:30:26
33	33	\|
34	34	LL \| let z = call_it_once(square, 22);

tests/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr+3-3

...	...	@@ -1,4 +1,4 @@
1		error[E0277]: expected a `Fn(&isize)` closure, found `unsafe fn(isize) -> isize {square}`
	1	error[E0277]: expected an `Fn(&isize)` closure, found `unsafe fn(isize) -> isize {square}`
2	2	--> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:21:21
3	3	\|
4	4	LL \| let x = call_it(&square, 22);
...	...	@@ -14,7 +14,7 @@ note: required by a bound in `call_it`
14	14	LL \| fn call_it<F: Fn(&isize) -> isize>(_: &F, _: isize) -> isize {
15	15	\| ^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it`
16	16
17		error[E0277]: expected a `FnMut(&isize)` closure, found `unsafe fn(isize) -> isize {square}`
	17	error[E0277]: expected an `FnMut(&isize)` closure, found `unsafe fn(isize) -> isize {square}`
18	18	--> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:26:25
19	19	\|
20	20	LL \| let y = call_it_mut(&mut square, 22);
...	...	@@ -30,7 +30,7 @@ note: required by a bound in `call_it_mut`
30	30	LL \| fn call_it_mut<F: FnMut(&isize) -> isize>(_: &mut F, _: isize) -> isize {
31	31	\| ^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it_mut`
32	32
33		error[E0277]: expected a `FnOnce(&isize)` closure, found `unsafe fn(isize) -> isize {square}`
	33	error[E0277]: expected an `FnOnce(&isize)` closure, found `unsafe fn(isize) -> isize {square}`
34	34	--> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:31:26
35	35	\|
36	36	LL \| let z = call_it_once(square, 22);