Auto merge of #115822 - compiler-errors:stabilize-rpitit, r=jackh726

Stabilize `async fn` and return-position `impl Trait` in trait

# Stabilization report

This report proposes the stabilization of `#![feature(return_position_impl_trait_in_trait)]` ([RPITIT][RFC 3425]) and `#![feature(async_fn_in_trait)]` ([AFIT][RFC 3185]). These are both long awaited features that increase the expressiveness of the Rust language and trait system.

Closes #91611

[RFC 3185]: https://rust-lang.github.io/rfcs/3185-static-async-fn-in-trait.html
[RFC 3425]: https://rust-lang.github.io/rfcs/3425-return-position-impl-trait-in-traits.html

## Updates from thread

The thread has covered two major concerns:

* [Given that we don't have RTN, what should we stabilize?](https://github.com/rust-lang/rust/pull/115822#issuecomment-1731149475) -- proposed resolution is [adding a lint](https://github.com/rust-lang/rust/pull/115822#issuecomment-1728354622) and [careful messaging](https://github.com/rust-lang/rust/pull/115822#issuecomment-1731136169)
* [Interaction between outlives bounds and capture semantics](https://github.com/rust-lang/rust/pull/115822#issuecomment-1731153952) -- This is fixable in a forwards-compatible way via #116040, and also eventually via ATPIT.

## Stabilization Summary

This stabilization allows the following examples to work.

### Example of return-position `impl Trait` in trait definition

```rust
trait Bar {
    fn bar(self) -> impl Send;
}
```

This declares a trait method that returns *some* type that implements `Send`.  It's similar to writing the following using an associated type, except that the associated type is anonymous.

```rust
trait Bar {
    type _0: Send;
    fn bar(self) -> Self::_0;
}
```

### Example of return-position `impl Trait` in trait implementation

```rust
impl Bar for () {
    fn bar(self) -> impl Send {}
}
```

This defines a method implementation that returns an opaque type, just like [RPIT][RFC 1522] does, except that all in-scope lifetimes are captured in the opaque type (as is already true for `async fn` and as is expected to be true for RPIT in Rust Edition 2024), as described below.

[RFC 1522]: https://rust-lang.github.io/rfcs/1522-conservative-impl-trait.html

### Example of `async fn` in trait

```rust
trait Bar {
    async fn bar(self);
}

impl Bar for () {
    async fn bar(self) {}
}
```

This declares a trait method that returns *some* [`Future`](https://doc.rust-lang.org/core/future/trait.Future.html) and a corresponding method implementation.  This is equivalent to writing the following using RPITIT.

```rust
use core::future::Future;

trait Bar {
    fn bar(self) -> impl Future<Output = ()>;
}

impl Bar for () {
    fn bar(self) -> impl Future<Output = ()> { async {} }
}
```

The desirability of this desugaring being available is part of why RPITIT and AFIT are being proposed for stabilization at the same time.

## Motivation

Long ago, Rust added [RPIT][RFC 1522] and [`async`/`await`][RFC 2394].  These are major features that are widely used in the ecosystem.  However, until now, these feature could not be used in *traits* and trait implementations.  This left traits as a kind of second-class citizen of the language.  This stabilization fixes that.

[RFC 2394]: https://rust-lang.github.io/rfcs/2394-async_await.html

### `async fn` in trait

Async/await allows users to write asynchronous code much easier than they could before. However, it doesn't play nice with other core language features that make Rust the great language it is, like traits. Support for `async fn` in traits has been long anticipated and was not added before due to limitations in the compiler that have now been lifted.

`async fn` in traits will unblock a lot of work in the ecosystem and the standard library. It is not currently possible to write a trait that is implemented using `async fn`. The workarounds that exist are undesirable because they require allocation and dynamic dispatch, and any trait that uses them will become obsolete once native `async fn` in trait is stabilized.

We also have ample evidence that there is demand for this feature from the [`async-trait` crate][async-trait], which emulates the feature using dynamic dispatch. The async-trait crate is currently the #5 async crate on crates.io ranked by recent downloads, receiving over 78M all-time downloads. According to a [recent analysis][async-trait-analysis], 4% of all crates use the `#[async_trait]` macro it provides, representing 7% of all function and method signatures in trait definitions on crates.io. We think this is a *lower bound* on demand for the feature, because users are unlikely to use `#[async_trait]` on public traits on crates.io for the reasons already given.

[async-trait]: https://crates.io/crates/async-trait
[async-trait-analysis]: https://rust-lang.zulipchat.com/#narrow/stream/315482-t-compiler.2Fetc.2Fopaque-types/topic/RPIT.20capture.20rules.20.28capturing.20everything.29/near/389496292

### Return-position `impl Trait` in trait

`async fn` always desugars to a function that returns `impl Future`.

```rust!
async fn foo() -> i32 { 100 }

// Equivalent to:
fn foo() -> impl Future<Output = i32> { async { 100 } }
```

All `async fn`s today can be rewritten this way. This is useful because it allows adding behavior that runs at the time of the function call, before the first `.await` on the returned future.

In the spirit of supporting the same set of features on `async fn` in traits that we do outside of traits, it makes sense to stabilize this as well. As described by the [RPITIT RFC][rpitit-rfc], this includes the ability to mix and match the equivalent forms in traits and their corresponding impls:

```rust!
trait Foo {
    async fn foo(self) -> i32;
}

// Can be implemented as:
impl Foo for MyType {
    fn foo(self) -> impl Future<Output = i32> {
        async { 100 }
    }
}
```

Return-position `impl Trait` in trait is useful for cases beyond async, just as regular RPIT is. As a simple example, the RFC showed an alternative way of writing the `IntoIterator` trait with one fewer associated type.

```rust!
trait NewIntoIterator {
    type Item;
    fn new_into_iter(self) -> impl Iterator<Item = Self::Item>;
}

impl<T> NewIntoIterator for Vec<T> {
    type Item = T;
    fn new_into_iter(self) -> impl Iterator<Item = T> {
        self.into_iter()
    }
}
```

[rpitit-rfc]: https://rust-lang.github.io/rfcs/3425-return-position-impl-trait-in-traits.html

## Major design decisions

This section describes the major design decisions that were reached after the RFC was accepted:

- EDIT: Lint against async fn in trait definitions

    - Until the [send bound problem](https://smallcultfollowing.com/babysteps/blog/2023/02/01/async-trait-send-bounds-part-1-intro/) is resolved, the use of `async fn` in trait definitions could lead to a bad experience for people using work-stealing executors (by far the most popular choice). However, there are significant use cases for which the current support is all that is needed (single-threaded executors, such as those used in embedded use cases, as well as thread-per-core setups). We are prioritizing serving users well over protecting people from misuse, and therefore, we opt to stabilize the full range of functionality; however, to help steer people correctly, we are will issue a warning on the use of `async fn` in trait definitions that advises users about the limitations. (See [this summary comment](https://github.com/rust-lang/rust/pull/115822#issuecomment-1731149475) for the details of the concern, and [this comment](https://github.com/rust-lang/rust/pull/115822#issuecomment-1728354622) for more details about the reasoning that led to this conclusion.)

- Capture rules:

    - The RFC's initial capture rules for lifetimes in impls/traits were found to be imprecisely precise and to introduce various inconsistencies. After much discussion, the decision was reached to make `-> impl Trait` in traits/impls capture *all* in-scope parameters, including both lifetimes and types. This is a departure from the behavior of RPITs in other contexts; an RFC is currently being authored to change the behavior of RPITs in other contexts in a future edition.

    - Major discussion links:

        - [Lang team design meeting from 2023-07-26](https://hackmd.io/sFaSIMJOQcuwCdnUvCxtuQ?view)

- Refinement:

    - The [refinement RFC] initially proposed that impl signatures that are more specific than their trait are not allowed unless the `#[refine]` attribute was included, but left it as an open question how to implement this. The stabilized proposal is that it is not a hard error to omit `#[refine]`, but there is a lint which fires if the impl's return type is more precise than the trait. This greatly simplified the desugaring and implementation while still achieving the original goal of ensuring that users do not accidentally commit to a more specific return type than they intended.

    - Major discussion links:

        - [Zulip thread](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/.60.23.5Brefine.5D.60.20as.20a.20lint)

[refinement RFC]: https://rust-lang.github.io/rfcs/3245-refined-impls.html

## What is stabilized

### Async functions in traits and trait implementations

* `async fn` are now supported in traits and trait implementations.
* Associated functions in traits that are `async` may have default bodies.

### Return-position impl trait in traits and trait implementations

* Return-position `impl Trait`s are now supported in traits and trait implementations.
    * Return-position `impl Trait` in implementations are treated like regular return-position `impl Trait`s, and therefore behave according to the same inference rules for hidden type inference and well-formedness.
* Associated functions in traits that name return-position `impl Trait`s may have default bodies.
* Implementations may provide either concrete types or `impl Trait` for each corresponding `impl Trait` in the trait method signature.

For a detailed exploration of the technical implementation of return-position `impl Trait` in traits, see [the dev guide](https://rustc-dev-guide.rust-lang.org/return-position-impl-trait-in-trait.html).

### Mixing `async fn` in trait and return-position `impl Trait` in trait

A trait function declaration that is `async fn ..() -> T` may be satisfied by an implementation function that returns `impl Future<Output = T>`, or vice versa.

```rust
trait Async {
    async fn hello();
}

impl Async for () {
    fn hello() -> impl Future<Output = ()> {
        async {}
    }
}

trait RPIT {
    fn hello() -> impl Future<Output = String>;
}

impl RPIT for () {
    async fn hello() -> String {
        "hello".to_string()
    }
}
```

### Return-position `impl Trait` in traits and trait implementations capture all in-scope lifetimes

Described above in "major design decisions".

### Return-position `impl Trait` in traits are "always revealing"

When a trait uses `-> impl Trait` in return position, it logically desugars to an associated type that represents the return (the actual implementation in the compiler is different, as described below). The value of this associated type is determined by the actual return type written in the impl; if the impl also uses `-> impl Trait` as the return type, then the value of the associated type is an opaque type scoped to the impl method (similar to what you would get when calling an inherent function returning `-> impl Trait`). As with any associated type, the value of this special associated type can be revealed by the compiler if the compiler can figure out what impl is being used.

For example, given this trait:

```rust
trait AsDebug {
    fn as_debug(&self) -> impl Debug;
}
```

A function working with the trait generically is only able to see that the return value is `Debug`:

```rust
fn foo<T: AsDebug>(t: &T) {
    let u = t.as_debug();
    println!("{}", u); // ERROR: `u` is not known to implement `Display`
}
```

But if a function calls `as_debug` on a known type (say, `u32`), it may be able to resolve the return type more specifically, if that implementation specifies a concrete type as well:

```rust
impl AsDebug for u32 {
    fn as_debug(&self) -> u32 {
        *self
    }
}

fn foo(t: &u32) {
    let u: u32 = t.as_debug(); // OK!
    println!("{}",  t.as_debug()); // ALSO OK (since `u32: Display`).
}
```

The return type used in the impl therefore represents a **semver binding** promise from the impl author that the return type of `<u32 as AsDebug>::as_debug` will not change. This could come as a surprise to users, who might expect that they are free to change the return type to any other type that implements `Debug`. To address this, we include a [`refining_impl_trait` lint](https://github.com/rust-lang/rust/pull/115582) that warns if the impl uses a specific type -- the `impl AsDebug for u32` above, for example, would toggle the lint.

The lint message explains what is going on and encourages users to `allow` the lint to indicate that they meant to refine the return type:

```rust
impl AsDebug for u32 {
    #[allow(refining_impl_trait)]
    fn as_debug(&self) -> u32 {
        *self
    }
}
```

[RFC #3245](https://github.com/rust-lang/rfcs/pull/3245) proposed a new attribute, `#[refine]`, that could also be used to "opt-in" to refinements like this (and which would then silence the lint). That RFC is not currently implemented -- the `#[refine]` attribute is also expected to reveal other details from the signature and has not yet been fully implemented.

### Return-position `impl Trait` and `async fn` in traits are opted-out of object safety checks when the parent function has `Self: Sized`

```rust
trait IsObjectSafe {
    fn rpit() -> impl Sized where Self: Sized;
    async fn afit() where Self: Sized;
}
```

Traits that mention return-position `impl Trait` or `async fn` in trait when the associated function includes a `Self: Sized` bound will remain object safe. That is because the associated function that defines them will be opted-out of the vtable of the trait, and the associated types will be unnameable from any trait object.

This can alternatively be seen as a consequence of https://github.com/rust-lang/rust/pull/112319#issue-1742251747 and the desugaring of return-position `impl Trait` in traits to associated types which inherit the where-clauses of the associated function that defines them.

## What isn't stabilized (aka, potential future work)

### Dynamic dispatch

As stabilized, traits containing RPITIT and AFIT are **not dyn compatible**. This means that you cannot create `dyn Trait` objects from them and can only use static dispatch. The reason for this limitation is that dynamic dispatch support for RPITIT and AFIT is more complex than static dispatch, as described on the [async fundamentals page](https://rust-lang.github.io/async-fundamentals-initiative/evaluation/challenges/dyn_traits.html). The primary challenge to using `dyn Trait` in today's Rust is that **`dyn Trait` today must list the values of all associated types**. This means you would have to write `dyn for<'s> Trait<Foo<'s> = XXX>` where `XXX` is the future type defined by the impl, such as `F_A`. This is not only verbose (or impossible), it also uniquely ties the `dyn Trait` to a particular impl, defeating the whole point of `dyn Trait`.

The precise design for handling dynamic dispatch is not yet determined. Top candidates include:

- [callee site selection][], in which we permit unsized return values so that the return type for an `-> impl Foo` method be can be `dyn Foo`, but then users must specify the type of wide pointer at the call-site in some fashion.

- [`dyn*`][], where we create a built-in encapsulation of a "wide pointer" and map the associated type corresponding to an RPITIT to the corresponding `dyn*` type (`dyn*` itself is not exposed to users as a type in this proposal, though that could be a future extension).

[callee site selection]: https://smallcultfollowing.com/babysteps/blog/2022/09/21/dyn-async-traits-part-9-callee-site-selection/

[`dyn*`]: https://smallcultfollowing.com/babysteps/blog/2022/03/29/dyn-can-we-make-dyn-sized/

### Where-clause bounds on return-position `impl Trait` in traits or async futures (RTN/ART)

One limitation of async fn in traits and RPITIT as stabilized is that there is no way for users to write code that adds additional bounds beyond those listed in the `-> impl Trait`. The most common example is wanting to write a generic function that requires that the future returned from an `async fn` be `Send`:

```rust
trait Greet {
    async fn greet(&self);
}

fn greet_in_parallel<G: Greet>(g: &G) {
    runtime::spawn(async move {
        g.greet().await; //~ ERROR: future returned by `greet` may not be `Send`
    })
}
```

Currently, since the associated types added for the return type are anonymous, there is no where-clause that could be added to make this code compile.

There have been various proposals for how to address this problem (e.g., [return type notation][rtn] or having an annotation to give a name to the associated type), but we leave the selection of one of those mechanisms to future work.

[rtn]: https://smallcultfollowing.com/babysteps/blog/2023/02/13/return-type-notation-send-bounds-part-2/

In the meantime, there are workarounds that one can use to address this problem, listed below.

#### Require all futures to be `Send`

For many users, the trait may only ever be used with `Send` futures, in which case one can write an explicit `impl Future + Send`:

```rust
trait Greet {
    fn greet(&self) -> impl Future<Output = ()> + Send;
}
```

The nice thing about this is that it is still compatible with using `async fn` in the trait impl. In the async working group case studies, we found that this could work for the [builder provider API](https://rust-lang.github.io/async-fundamentals-initiative/evaluation/case-studies/builder-provider-api.html). This is also the default approach used by the `#[async_trait]` crate which, as we have noted, has seen widespread adoption.

#### Avoid generics

This problem only applies when the `Self` type is generic. If the `Self` type is known, then the precise return type from an `async fn` is revealed, and the `Send` bound can be inferred thanks to auto-trait leakage. Even in cases where generics may appear to be required, it is sometimes possible to rewrite the code to avoid them. The [socket handler refactor](https://rust-lang.github.io/async-fundamentals-initiative/evaluation/case-studies/socket-handler.html) case study provides one such example.

### Unify capture behavior for `-> impl Trait` in inherent methods and traits

As stabilized, the capture behavior for `-> impl Trait` in a trait (whether as part of an async fn or a RPITIT) captures all types and lifetimes, whereas the existing behavior for inherent methods only captures types and lifetimes that are explicitly referenced. Capturing all lifetimes in traits was necessary to avoid various surprising inconsistencies; the expressed intent of the lang team is to extend that behavior so that we also capture all lifetimes in inherent methods, which would create more consistency and also address a common source of user confusion, but that will have to happen over the 2024 edition. The RFC is in progress. Should we opt not to accept that RFC, we can bring the capture behavior for `-> impl Trait` into alignment in other ways as part of the 2024 edition.

### `impl_trait_projections`

Orthgonal to `async_fn_in_trait` and `return_position_impl_trait_in_trait`, since it can be triggered on stable code. This will be stabilized separately in [#115659](https://github.com/rust-lang/rust/pull/115659).

<details>
If we try to write this code without `impl_trait_projections`, we will get an error:

```rust
#![feature(async_fn_in_trait)]

trait Foo {
    type Error;
    async fn foo(&mut self) -> Result<(), Self::Error>;
}

impl<T: Foo> Foo for &mut T {
    type Error = T::Error;
    async fn foo(&mut self) -> Result<(), Self::Error> {
        T::foo(self).await
    }
}
```

The error relates to the use of `Self` in a trait impl when the self type has a lifetime. It can be worked around by rewriting the impl not to use `Self`:

```rust
#![feature(async_fn_in_trait)]

trait Foo {
    type Error;
    async fn foo(&mut self) -> Result<(), Self::Error>;
}

impl<T: Foo> Foo for &mut T {
    type Error = T::Error;
    async fn foo(&mut self) -> Result<(), <&mut T as Foo>::Error> {
        T::foo(self).await
    }
}
```
</details>

## Tests

Tests are generally organized between return-position `impl Trait` and `async fn` in trait, when the distinction matters.
* RPITIT: https://github.com/rust-lang/rust/tree/master/tests/ui/impl-trait/in-trait
* AFIT: https://github.com/rust-lang/rust/tree/master/tests/ui/async-await/in-trait

## Remaining bugs and open issues

* #112047: Indirection introduced by `async fn` and return-position `impl Trait` in traits may hide cycles in opaque types, causing overflow errors that can only be discovered by monomorphization.
* #111105 - `async fn` in trait is susceptible to issues with checking auto traits on futures' generators, like regular `async`. This is a manifestation of #110338.
    * This was deemed not blocking because fixing it is forwards-compatible, and regular `async` is subject to the same issues.
* #104689: `async fn` and return-position `impl Trait` in trait requires the late-bound lifetimes in a trait and impl function signature to be equal.
    * This can be relaxed in the future with a smarter lexical region resolution algorithm.
* #102527: Nesting return-position `impl Trait` in trait deeply may result in slow compile times.
    * This has only been reported once, and can be fixed in the future.
* #108362: Inference between return types and generics of a function may have difficulties when there's an `.await`.
    * This isn't related to AFIT (https://github.com/rust-lang/rust/issues/108362#issuecomment-1717927918) -- using traits does mean that there's possibly easier ways to hit it.
* #112626: Because `async fn` and return-position `impl Trait` in traits lower to associated types, users may encounter strange behaviors when implementing circularly dependent traits.
    * This is not specific to RPITIT, and is a limitation of associated types: https://github.com/rust-lang/rust/issues/112626#issuecomment-1603405105
* **(Nightly)** #108309: `async fn` and return-position `impl Trait` in trait do not support specialization. This was deemed not blocking, since it can be fixed in the future (e.g. #108321) and specialization is a nightly feature.

#### (Nightly) Return type notation bugs

RTN is not being stabilized here, but there are some interesting outstanding bugs. None of them are blockers for AFIT/RPITIT, but I'm noting them for completeness.

<details>

* #109924 is a bug that occurs when a higher-ranked trait bound has both inference variables and associated types. This is pre-existing -- RTN just gives you a more convenient way of producing them. This should be fixed by the new trait solver.
* #109924 is a manifestation of a more general issue with `async` and auto-trait bounds: #110338. RTN does not cause this issue, just allows us to put `Send` bounds on the anonymous futures that we have in traits.
* #112569 is a bug similar to associated type bounds, where nested bounds are not implied correctly.

</details>

## Alternatives

### Do nothing

We could choose not to stabilize these features. Users that can use the `#[async_trait]` macro would continue to do so. Library maintainers would continue to avoid async functions in traits, potentially blocking the stable release of many useful crates.

### Stabilize `impl Trait` in associated type instead

AFIT and RPITIT solve the problem of returning unnameable types from trait methods. It is also possible to solve this by using another unstable feature, `impl Trait` in an associated type. Users would need to define an associated type in both the trait and trait impl:

```rust!
trait Foo {
    type Fut<'a>: Future<Output = i32> where Self: 'a;
    fn foo(&self) -> Self::Fut<'_>;
}

impl Foo for MyType {
    type Fut<'a> where Self: 'a = impl Future<Output = i32>;
    fn foo(&self) -> Self::Fut<'_> {
        async { 42 }
    }
}
```

This also has the advantage of allowing generic code to bound the associated type. However, it is substantially less ergonomic than either `async fn` or `-> impl Future`, and users still expect to be able to use those features in traits. **Even if this feature were stable, we would still want to stabilize AFIT and RPITIT.**

That said, we can have both. `impl Trait` in associated types is desireable because it can be used in existing traits with explicit associated types, among other reasons. We *should* stabilize this feature once it is ready, but that's outside the scope of this proposal.

### Use the old capture semantics for RPITIT

We could choose to make the capture rules for RPITIT consistent with the existing rules for RPIT. However, there was strong consensus in a recent [lang team meeting](https://hackmd.io/sFaSIMJOQcuwCdnUvCxtuQ?view) that we should *change* these rules, and furthermore that new features should adopt the new rules.

This is consistent with the tenet in RFC 3085 of favoring ["Uniform behavior across editions"](https://rust-lang.github.io/rfcs/3085-edition-2021.html#uniform-behavior-across-editions) when possible. It greatly reduces the complexity of the feature by not requiring us to answer, or implement, the design questions that arise out of the interaction between the current capture rules and traits. This reduction in complexity – and eventual technical debt – is exactly in line with the motivation listed in the aforementioned RFC.

### Make refinement a hard error

Refinement (`refining_impl_trait`) is only a concern for library authors, and therefore doesn't really warrant making into a deny-by-default warning or an error.

Additionally, refinement is currently checked via a lint that compares bounds in the `impl Trait`s in the trait and impl syntactically. This is good enough for a warning that can be opted-out, but not if this were a hard error, which would ideally be implemented using fully semantic, implicational logic. This was implemented (#111931), but also is an unnecessary burden on the type system for little pay-off.

## History

- Dec 7, 2021: [RFC #3185: Static async fn in traits](https://rust-lang.github.io/rfcs/3185-static-async-fn-in-trait.html) merged
- Sep 9, 2022: [Initial implementation](https://github.com/rust-lang/rust/pull/101224) of AFIT and RPITIT landed
- Jun 13, 2023: [RFC #3425: Return position `impl Trait` in traits](https://rust-lang.github.io/rfcs/3425-return-position-impl-trait-in-traits.html) merged

<!--These will render pretty when pasted into github-->
Non-exhaustive list of PRs that are particularly relevant to the implementation:

- #101224
- #103491
- #104592
- #108141
- #108319
- #108672
- #112988
- #113182 (later made redundant by #114489)
- #113215
- #114489
- #115467
- #115582

Doc co-authored by `@nikomatsakis,` `@tmandry,` `@traviscross.` Thanks also to `@spastorino,` `@cjgillot` (for changes to opaque captures!), `@oli-obk` for many reviews, and many other contributors and issue-filers. Apologies if I left your name off 😺

234 files changed, 324 insertions, 1060 deletions

diff --git a/compiler/rustc_ast_lowering/messages.ftl b/compiler/rustc_ast_lowering/messages.ftl
index aaeef1ff77d..b9fe99ac72f 100644
--- a/compiler/rustc_ast_lowering/messages.ftl
+++ b/compiler/rustc_ast_lowering/messages.ftl
@@ -136,12 +136,6 @@ ast_lowering_template_modifier = template modifier
 
 ast_lowering_this_not_async = this is not `async`
 
-ast_lowering_trait_fn_async =
-    functions in traits cannot be declared `async`
-    .label = `async` because of this
-    .note = `async` trait functions are not currently supported
-    .note2 = consider using the `async-trait` crate: https://crates.io/crates/async-trait
-
 ast_lowering_underscore_expr_lhs_assign =
     in expressions, `_` can only be used on the left-hand side of an assignment
     .label = `_` not allowed here
diff --git a/compiler/rustc_ast_lowering/src/errors.rs b/compiler/rustc_ast_lowering/src/errors.rs
index a63bd4f8a02..fe0c7d101c1 100644
--- a/compiler/rustc_ast_lowering/src/errors.rs
+++ b/compiler/rustc_ast_lowering/src/errors.rs
@@ -354,17 +354,6 @@ pub struct InclusiveRangeWithNoEnd {
     pub span: Span,
 }
 
-#[derive(Diagnostic, Clone, Copy)]
-#[diag(ast_lowering_trait_fn_async, code = "E0706")]
-#[note]
-#[note(ast_lowering_note2)]
-pub struct TraitFnAsync {
-    #[primary_span]
-    pub fn_span: Span,
-    #[label]
-    pub span: Span,
-}
-
 #[derive(Diagnostic)]
 pub enum BadReturnTypeNotation {
     #[diag(ast_lowering_bad_return_type_notation_inputs)]
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index 7e3ada9c123..92c548ec2ec 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -40,7 +40,7 @@
 #[macro_use]
 extern crate tracing;
 
-use crate::errors::{AssocTyParentheses, AssocTyParenthesesSub, MisplacedImplTrait, TraitFnAsync};
+use crate::errors::{AssocTyParentheses, AssocTyParenthesesSub, MisplacedImplTrait};
 
 use rustc_ast::ptr::P;
 use rustc_ast::visit;
@@ -271,8 +271,6 @@ enum ImplTraitPosition {
     ClosureReturn,
     PointerReturn,
     FnTraitReturn,
-    TraitReturn,
-    ImplReturn,
     GenericDefault,
     ConstTy,
     StaticTy,
@@ -302,8 +300,6 @@ impl std::fmt::Display for ImplTraitPosition {
             ImplTraitPosition::ClosureReturn => "closure return types",
             ImplTraitPosition::PointerReturn => "`fn` pointer return types",
             ImplTraitPosition::FnTraitReturn => "`Fn` trait return types",
-            ImplTraitPosition::TraitReturn => "trait method return types",
-            ImplTraitPosition::ImplReturn => "`impl` method return types",
             ImplTraitPosition::GenericDefault => "generic parameter defaults",
             ImplTraitPosition::ConstTy => "const types",
             ImplTraitPosition::StaticTy => "static types",
@@ -334,20 +330,9 @@ impl FnDeclKind {
         matches!(self, FnDeclKind::Fn | FnDeclKind::Inherent | FnDeclKind::Impl | FnDeclKind::Trait)
     }
 
-    fn return_impl_trait_allowed(&self, tcx: TyCtxt<'_>) -> bool {
+    fn return_impl_trait_allowed(&self) -> bool {
         match self {
-            FnDeclKind::Fn | FnDeclKind::Inherent => true,
-            FnDeclKind::Impl if tcx.features().return_position_impl_trait_in_trait => true,
-            FnDeclKind::Trait if tcx.features().return_position_impl_trait_in_trait => true,
-            _ => false,
-        }
-    }
-
-    fn async_fn_allowed(&self, tcx: TyCtxt<'_>) -> bool {
-        match self {
-            FnDeclKind::Fn | FnDeclKind::Inherent => true,
-            FnDeclKind::Impl if tcx.features().async_fn_in_trait => true,
-            FnDeclKind::Trait if tcx.features().async_fn_in_trait => true,
+            FnDeclKind::Fn | FnDeclKind::Inherent | FnDeclKind::Impl | FnDeclKind::Trait => true,
             _ => false,
         }
     }
@@ -1805,53 +1790,30 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             self.lower_ty_direct(&param.ty, &itctx)
         }));
 
-        let output = if let Some((ret_id, span)) = make_ret_async {
-            if !kind.async_fn_allowed(self.tcx) {
-                match kind {
-                    FnDeclKind::Trait | FnDeclKind::Impl => {
-                        self.tcx
-                            .sess
-                            .create_feature_err(
-                                TraitFnAsync { fn_span, span },
-                                sym::async_fn_in_trait,
-                            )
-                            .emit();
-                    }
-                    _ => {
-                        self.tcx.sess.emit_err(TraitFnAsync { fn_span, span });
-                    }
-                }
-            }
-
+        let output = if let Some((ret_id, _span)) = make_ret_async {
             let fn_def_id = self.local_def_id(fn_node_id);
             self.lower_async_fn_ret_ty(&decl.output, fn_def_id, ret_id, kind, fn_span)
         } else {
             match &decl.output {
                 FnRetTy::Ty(ty) => {
-                    let context = if kind.return_impl_trait_allowed(self.tcx) {
+                    let context = if kind.return_impl_trait_allowed() {
                         let fn_def_id = self.local_def_id(fn_node_id);
                         ImplTraitContext::ReturnPositionOpaqueTy {
                             origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
                             fn_kind: kind,
                         }
                     } else {
-                        let position = match kind {
-                            FnDeclKind::Fn | FnDeclKind::Inherent => {
-                                unreachable!("fn should allow in-band lifetimes")
+                        ImplTraitContext::Disallowed(match kind {
+                            FnDeclKind::Fn
+                            | FnDeclKind::Inherent
+                            | FnDeclKind::Trait
+                            | FnDeclKind::Impl => {
+                                unreachable!("fn should allow return-position impl trait in traits")
                             }
                             FnDeclKind::ExternFn => ImplTraitPosition::ExternFnReturn,
                             FnDeclKind::Closure => ImplTraitPosition::ClosureReturn,
                             FnDeclKind::Pointer => ImplTraitPosition::PointerReturn,
-                            FnDeclKind::Trait => ImplTraitPosition::TraitReturn,
-                            FnDeclKind::Impl => ImplTraitPosition::ImplReturn,
-                        };
-                        match kind {
-                            FnDeclKind::Trait | FnDeclKind::Impl => ImplTraitContext::FeatureGated(
-                                position,
-                                sym::return_position_impl_trait_in_trait,
-                            ),
-                            _ => ImplTraitContext::Disallowed(position),
-                        }
+                        })
                     };
                     hir::FnRetTy::Return(self.lower_ty(ty, &context))
                 }
@@ -1924,18 +1886,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 let future_bound = this.lower_async_fn_output_type_to_future_bound(
                     output,
                     span,
-                    if let FnDeclKind::Trait = fn_kind
-                        && !this.tcx.features().return_position_impl_trait_in_trait
-                    {
-                        ImplTraitContext::FeatureGated(
-                            ImplTraitPosition::TraitReturn,
-                            sym::return_position_impl_trait_in_trait,
-                        )
-                    } else {
-                        ImplTraitContext::ReturnPositionOpaqueTy {
-                            origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
-                            fn_kind,
-                        }
+                    ImplTraitContext::ReturnPositionOpaqueTy {
+                        origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id),
+                        fn_kind,
                     },
                 );
                 arena_vec![this; future_bound]
diff --git a/compiler/rustc_error_codes/src/error_codes/E0706.md b/compiler/rustc_error_codes/src/error_codes/E0706.md
index fabd855a222..a09abb59ba8 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0706.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0706.md
@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 `async fn`s are not yet supported in traits in Rust.
 
 Erroneous code example:
 
-```compile_fail,edition2018
+```ignore,edition2018
 trait T {
     // Neither case is currently supported.
     async fn foo() {}
@@ -13,7 +15,7 @@ trait T {
 `async fn`s return an `impl Future`, making the following two examples
 equivalent:
 
-```edition2018,ignore (example-of-desugaring-equivalence)
+```ignore,edition2018 (example-of-desugaring-equivalence)
 async fn foo() -> User {
     unimplemented!()
 }
diff --git a/compiler/rustc_feature/src/accepted.rs b/compiler/rustc_feature/src/accepted.rs
index bcc64d48ddd..b198876b05c 100644
--- a/compiler/rustc_feature/src/accepted.rs
+++ b/compiler/rustc_feature/src/accepted.rs
@@ -67,6 +67,8 @@ declare_features! (
     (accepted, associated_types, "1.0.0", None, None),
     /// Allows free and inherent `async fn`s, `async` blocks, and `<expr>.await` expressions.
     (accepted, async_await, "1.39.0", Some(50547), None),
+    /// Allows async functions to be declared, implemented, and used in traits.
+    (accepted, async_fn_in_trait, "CURRENT_RUSTC_VERSION", Some(91611), None),
     /// Allows all literals in attribute lists and values of key-value pairs.
     (accepted, attr_literals, "1.30.0", Some(34981), None),
     /// Allows overloading augmented assignment operations like `a += b`.
@@ -306,6 +308,8 @@ declare_features! (
     (accepted, repr_packed, "1.33.0", Some(33158), None),
     /// Allows `#[repr(transparent)]` attribute on newtype structs.
     (accepted, repr_transparent, "1.28.0", Some(43036), None),
+    /// Allows return-position `impl Trait` in traits.
+    (accepted, return_position_impl_trait_in_trait, "CURRENT_RUSTC_VERSION", Some(91611), None),
     /// Allows code like `let x: &'static u32 = &42` to work (RFC 1414).
     (accepted, rvalue_static_promotion, "1.21.0", Some(38865), None),
     /// Allows `Self` in type definitions (RFC 2300).
diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index d016e24e0c8..ef672487b98 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -351,8 +351,6 @@ declare_features! (
     (active, associated_type_defaults, "1.2.0", Some(29661), None),
     /// Allows `async || body` closures.
     (active, async_closure, "1.37.0", Some(62290), None),
-    /// Allows async functions to be declared, implemented, and used in traits.
-    (active, async_fn_in_trait, "1.66.0", Some(91611), None),
     /// Allows `#[track_caller]` on async functions.
     (active, async_fn_track_caller, "1.73.0", Some(110011), None),
     /// Allows builtin # foo() syntax
@@ -551,8 +549,6 @@ declare_features! (
     (incomplete, repr128, "1.16.0", Some(56071), None),
     /// Allows `repr(simd)` and importing the various simd intrinsics.
     (active, repr_simd, "1.4.0", Some(27731), None),
-    /// Allows return-position `impl Trait` in traits.
-    (active, return_position_impl_trait_in_trait, "1.65.0", Some(91611), None),
     /// Allows bounding the return type of AFIT/RPITIT.
     (incomplete, return_type_notation, "1.70.0", Some(109417), None),
     /// Allows `extern "rust-cold"`.
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index 486aac21972..87a30f9f813 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -783,21 +783,21 @@ fn check_impl_items_against_trait<'tcx>(
                 let (msg, feature) = if tcx.asyncness(def_id).is_async() {
                     (
                         format!("async {descr} in trait cannot be specialized"),
-                        sym::async_fn_in_trait,
+                        "async functions in traits",
                     )
                 } else {
                     (
                         format!(
                             "{descr} with return-position `impl Trait` in trait cannot be specialized"
                         ),
-                        sym::return_position_impl_trait_in_trait,
+                        "return position `impl Trait` in traits",
                     )
                 };
                 tcx.sess
                     .struct_span_err(tcx.def_span(def_id), msg)
                     .note(format!(
                         "specialization behaves in inconsistent and \
-                        surprising ways with `#![feature({feature})]`, \
+                        surprising ways with {feature}, \
                         and for now is disallowed"
                     ))
                     .emit();
diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
index f1514ecf69c..fc8e5a795fb 100644
--- a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
+++ b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
@@ -633,8 +633,6 @@ fn compare_asyncness<'tcx>(
 /// For example, given the sample code:
 ///
 /// ```
-/// #![feature(return_position_impl_trait_in_trait)]
-///
 /// use std::ops::Deref;
 ///
 /// trait Foo {
diff --git a/compiler/rustc_lint/src/async_fn_in_trait.rs b/compiler/rustc_lint/src/async_fn_in_trait.rs
index ff4c81e2fc9..53c5f4cd26e 100644
--- a/compiler/rustc_lint/src/async_fn_in_trait.rs
+++ b/compiler/rustc_lint/src/async_fn_in_trait.rs
@@ -11,7 +11,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// # #![feature(async_fn_in_trait)]
     /// pub trait Trait {
     ///     async fn method(&self);
     /// }
@@ -33,7 +32,6 @@ declare_lint! {
     /// For example, this code is invalid:
     ///
     /// ```rust,compile_fail
-    /// # #![feature(async_fn_in_trait)]
     /// pub trait Trait {
     ///     async fn method(&self) {}
     /// }
@@ -51,7 +49,6 @@ declare_lint! {
     /// For example, instead of:
     ///
     /// ```rust
-    /// # #![feature(async_fn_in_trait)]
     /// pub trait Trait {
     ///     async fn method(&self) {}
     /// }
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 0e242c1febd..96a98393fb2 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -4534,7 +4534,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust,compile_fail
-    /// #![feature(return_position_impl_trait_in_trait)]
     /// #![deny(refining_impl_trait)]
     ///
     /// use std::fmt::Display;
diff --git a/src/tools/clippy/tests/ui/implied_bounds_in_impls.fixed b/src/tools/clippy/tests/ui/implied_bounds_in_impls.fixed
index a50fa0ccf6e..fa117aaddcd 100644
--- a/src/tools/clippy/tests/ui/implied_bounds_in_impls.fixed
+++ b/src/tools/clippy/tests/ui/implied_bounds_in_impls.fixed
@@ -1,6 +1,5 @@
 #![warn(clippy::implied_bounds_in_impls)]
 #![allow(dead_code)]
-#![feature(return_position_impl_trait_in_trait)]
 
 use std::ops::{Deref, DerefMut};
 
diff --git a/src/tools/clippy/tests/ui/implied_bounds_in_impls.rs b/src/tools/clippy/tests/ui/implied_bounds_in_impls.rs
index e74ed4425b8..c96aac151a7 100644
--- a/src/tools/clippy/tests/ui/implied_bounds_in_impls.rs
+++ b/src/tools/clippy/tests/ui/implied_bounds_in_impls.rs
@@ -1,6 +1,5 @@
 #![warn(clippy::implied_bounds_in_impls)]
 #![allow(dead_code)]
-#![feature(return_position_impl_trait_in_trait)]
 
 use std::ops::{Deref, DerefMut};
 
diff --git a/src/tools/clippy/tests/ui/implied_bounds_in_impls.stderr b/src/tools/clippy/tests/ui/implied_bounds_in_impls.stderr
index 72dc2a183a3..fb44f2aba17 100644
--- a/src/tools/clippy/tests/ui/implied_bounds_in_impls.stderr
+++ b/src/tools/clippy/tests/ui/implied_bounds_in_impls.stderr
@@ -1,5 +1,5 @@
 error: this bound is already specified as the supertrait of `DerefMut<Target = T>`
-  --> $DIR/implied_bounds_in_impls.rs:13:36
+  --> $DIR/implied_bounds_in_impls.rs:12:36
    |
 LL | fn deref_derefmut<T>(x: T) -> impl Deref<Target = T> + DerefMut<Target = T> {
    |                                    ^^^^^^^^^^^^^^^^^
@@ -13,7 +13,7 @@ LL + fn deref_derefmut<T>(x: T) -> impl DerefMut<Target = T> {
    |
 
 error: this bound is already specified as the supertrait of `GenericSubtrait<U, W, U>`
-  --> $DIR/implied_bounds_in_impls.rs:30:37
+  --> $DIR/implied_bounds_in_impls.rs:29:37
    |
 LL | fn generics_implied<U, W>() -> impl GenericTrait<W> + GenericSubtrait<U, W, U>
    |                                     ^^^^^^^^^^^^^^^
@@ -25,7 +25,7 @@ LL + fn generics_implied<U, W>() -> impl GenericSubtrait<U, W, U>
    |
 
 error: this bound is already specified as the supertrait of `GenericSubtrait<(), i32, V>`
-  --> $DIR/implied_bounds_in_impls.rs:36:40
+  --> $DIR/implied_bounds_in_impls.rs:35:40
    |
 LL | fn generics_implied_multi<V>() -> impl GenericTrait<i32> + GenericTrait2<V> + GenericSubtrait<(), i32, V> {}
    |                                        ^^^^^^^^^^^^^^^^^
@@ -37,7 +37,7 @@ LL + fn generics_implied_multi<V>() -> impl GenericTrait2<V> + GenericSubtrait<(
    |
 
 error: this bound is already specified as the supertrait of `GenericSubtrait<(), i32, V>`
-  --> $DIR/implied_bounds_in_impls.rs:36:60
+  --> $DIR/implied_bounds_in_impls.rs:35:60
    |
 LL | fn generics_implied_multi<V>() -> impl GenericTrait<i32> + GenericTrait2<V> + GenericSubtrait<(), i32, V> {}
    |                                                            ^^^^^^^^^^^^^^^^
@@ -49,7 +49,7 @@ LL + fn generics_implied_multi<V>() -> impl GenericTrait<i32> + GenericSubtrait<
    |
 
 error: this bound is already specified as the supertrait of `GenericSubtrait<(), T, V>`
-  --> $DIR/implied_bounds_in_impls.rs:38:44
+  --> $DIR/implied_bounds_in_impls.rs:37:44
    |
 LL | fn generics_implied_multi2<T, V>() -> impl GenericTrait<T> + GenericTrait2<V> + GenericSubtrait<(), T, V>
    |                                            ^^^^^^^^^^^^^^^
@@ -61,7 +61,7 @@ LL + fn generics_implied_multi2<T, V>() -> impl GenericTrait2<V> + GenericSubtra
    |
 
 error: this bound is already specified as the supertrait of `GenericSubtrait<(), T, V>`
-  --> $DIR/implied_bounds_in_impls.rs:38:62
+  --> $DIR/implied_bounds_in_impls.rs:37:62
    |
 LL | fn generics_implied_multi2<T, V>() -> impl GenericTrait<T> + GenericTrait2<V> + GenericSubtrait<(), T, V>
    |                                                              ^^^^^^^^^^^^^^^^
@@ -73,7 +73,7 @@ LL + fn generics_implied_multi2<T, V>() -> impl GenericTrait<T> + GenericSubtrai
    |
 
 error: this bound is already specified as the supertrait of `GenericSubtrait<(), i32, ()>`
-  --> $DIR/implied_bounds_in_impls.rs:48:28
+  --> $DIR/implied_bounds_in_impls.rs:47:28
    |
 LL | fn generics_same() -> impl GenericTrait<i32> + GenericSubtrait<(), i32, ()> {}
    |                            ^^^^^^^^^^^^^^^^^
@@ -85,7 +85,7 @@ LL + fn generics_same() -> impl GenericSubtrait<(), i32, ()> {}
    |
 
 error: this bound is already specified as the supertrait of `DerefMut<Target = u8>`
-  --> $DIR/implied_bounds_in_impls.rs:52:20
+  --> $DIR/implied_bounds_in_impls.rs:51:20
    |
 LL |     fn f() -> impl Deref + DerefMut<Target = u8>;
    |                    ^^^^^
@@ -97,7 +97,7 @@ LL +     fn f() -> impl DerefMut<Target = u8>;
    |
 
 error: this bound is already specified as the supertrait of `DerefMut<Target = u8>`
-  --> $DIR/implied_bounds_in_impls.rs:57:20
+  --> $DIR/implied_bounds_in_impls.rs:56:20
    |
 LL |     fn f() -> impl Deref + DerefMut<Target = u8> {
    |                    ^^^^^
@@ -109,7 +109,7 @@ LL +     fn f() -> impl DerefMut<Target = u8> {
    |
 
 error: this bound is already specified as the supertrait of `DerefMut<Target = u8>`
-  --> $DIR/implied_bounds_in_impls.rs:63:20
+  --> $DIR/implied_bounds_in_impls.rs:62:20
    |
 LL |     fn f() -> impl Deref + DerefMut<Target = u8> {
    |                    ^^^^^
@@ -121,7 +121,7 @@ LL +     fn f() -> impl DerefMut<Target = u8> {
    |
 
 error: this bound is already specified as the supertrait of `PartialOrd`
-  --> $DIR/implied_bounds_in_impls.rs:74:41
+  --> $DIR/implied_bounds_in_impls.rs:73:41
    |
 LL |     fn default_generic_param1() -> impl PartialEq + PartialOrd + Debug {}
    |                                         ^^^^^^^^^
@@ -133,7 +133,7 @@ LL +     fn default_generic_param1() -> impl PartialOrd + Debug {}
    |
 
 error: this bound is already specified as the supertrait of `PartialOrd`
-  --> $DIR/implied_bounds_in_impls.rs:75:54
+  --> $DIR/implied_bounds_in_impls.rs:74:54
    |
 LL |     fn default_generic_param2() -> impl PartialOrd + PartialEq + Debug {}
    |                                                      ^^^^^^^^^
@@ -145,7 +145,7 @@ LL +     fn default_generic_param2() -> impl PartialOrd + Debug {}
    |
 
 error: this bound is already specified as the supertrait of `DoubleEndedIterator`
-  --> $DIR/implied_bounds_in_impls.rs:88:26
+  --> $DIR/implied_bounds_in_impls.rs:87:26
    |
 LL |     fn my_iter() -> impl Iterator<Item = u32> + DoubleEndedIterator {
    |                          ^^^^^^^^^^^^^^^^^^^^
@@ -157,7 +157,7 @@ LL +     fn my_iter() -> impl DoubleEndedIterator<Item = u32> {
    |
 
 error: this bound is already specified as the supertrait of `Copy`
-  --> $DIR/implied_bounds_in_impls.rs:93:27
+  --> $DIR/implied_bounds_in_impls.rs:92:27
    |
 LL |     fn f() -> impl Copy + Clone {
    |                           ^^^^^
@@ -169,7 +169,7 @@ LL +     fn f() -> impl Copy {
    |
 
 error: this bound is already specified as the supertrait of `Trait2<i32>`
-  --> $DIR/implied_bounds_in_impls.rs:107:21
+  --> $DIR/implied_bounds_in_impls.rs:106:21
    |
 LL |     fn f2() -> impl Trait1<i32, U = i64> + Trait2<i32> {}
    |                     ^^^^^^^^^^^^^^^^^^^^
@@ -181,7 +181,7 @@ LL +     fn f2() -> impl Trait2<i32, U = i64> {}
    |
 
 error: this bound is already specified as the supertrait of `Trait4<i8, X = i32>`
-  --> $DIR/implied_bounds_in_impls.rs:122:21
+  --> $DIR/implied_bounds_in_impls.rs:121:21
    |
 LL |     fn f3() -> impl Trait3<i8, i16, i64, X = i32, Y = i128> + Trait4<i8, X = i32> {}
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/tools/clippy/tests/ui/unused_async.rs b/src/tools/clippy/tests/ui/unused_async.rs
index 71722e9afd0..7ec8a3adb4c 100644
--- a/src/tools/clippy/tests/ui/unused_async.rs
+++ b/src/tools/clippy/tests/ui/unused_async.rs
@@ -1,5 +1,4 @@
 #![warn(clippy::unused_async)]
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/src/tools/clippy/tests/ui/unused_async.stderr b/src/tools/clippy/tests/ui/unused_async.stderr
index 077e8cacce1..c97a76a55cb 100644
--- a/src/tools/clippy/tests/ui/unused_async.stderr
+++ b/src/tools/clippy/tests/ui/unused_async.stderr
@@ -1,5 +1,5 @@
 error: unused `async` for function with no await statements
-  --> $DIR/unused_async.rs:13:5
+  --> $DIR/unused_async.rs:12:5
    |
 LL | /     async fn async_block_await() {
 LL | |
@@ -11,7 +11,7 @@ LL | |     }
    |
    = help: consider removing the `async` from this function
 note: `await` used in an async block, which does not require the enclosing function to be `async`
-  --> $DIR/unused_async.rs:16:23
+  --> $DIR/unused_async.rs:15:23
    |
 LL |             ready(()).await;
    |                       ^^^^^
@@ -19,7 +19,7 @@ LL |             ready(()).await;
    = help: to override `-D warnings` add `#[allow(clippy::unused_async)]`
 
 error: unused `async` for function with no await statements
-  --> $DIR/unused_async.rs:46:5
+  --> $DIR/unused_async.rs:45:5
    |
 LL |     async fn f3() {}
    |     ^^^^^^^^^^^^^^^^
@@ -27,7 +27,7 @@ LL |     async fn f3() {}
    = help: consider removing the `async` from this function
 
 error: unused `async` for function with no await statements
-  --> $DIR/unused_async.rs:59:1
+  --> $DIR/unused_async.rs:58:1
    |
 LL | / async fn foo() -> i32 {
 LL | |
@@ -38,7 +38,7 @@ LL | | }
    = help: consider removing the `async` from this function
 
 error: unused `async` for function with no await statements
-  --> $DIR/unused_async.rs:71:5
+  --> $DIR/unused_async.rs:70:5
    |
 LL | /     async fn unused(&self) -> i32 {
 LL | |
diff --git a/tests/rustdoc/async-trait-sig.rs b/tests/rustdoc/async-trait-sig.rs
index 2578bc8f7a1..db1848f716d 100644
--- a/tests/rustdoc/async-trait-sig.rs
+++ b/tests/rustdoc/async-trait-sig.rs
@@ -1,6 +1,5 @@
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 pub trait Foo {
diff --git a/tests/rustdoc/async-trait.rs b/tests/rustdoc/async-trait.rs
index a473e467473..8de95aac22c 100644
--- a/tests/rustdoc/async-trait.rs
+++ b/tests/rustdoc/async-trait.rs
@@ -1,7 +1,6 @@
 // aux-build:async-trait-dep.rs
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 extern crate async_trait_dep;
diff --git a/tests/rustdoc/auxiliary/async-trait-dep.rs b/tests/rustdoc/auxiliary/async-trait-dep.rs
index 10a55dd0260..d455ee99e09 100644
--- a/tests/rustdoc/auxiliary/async-trait-dep.rs
+++ b/tests/rustdoc/auxiliary/async-trait-dep.rs
@@ -1,6 +1,5 @@
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 pub trait Meow {
diff --git a/tests/rustdoc/inline_cross/auxiliary/async-fn.rs b/tests/rustdoc/inline_cross/auxiliary/async-fn.rs
index 767564ed145..564ca7d671e 100644
--- a/tests/rustdoc/inline_cross/auxiliary/async-fn.rs
+++ b/tests/rustdoc/inline_cross/auxiliary/async-fn.rs
@@ -1,4 +1,3 @@
-#![feature(async_fn_in_trait)]
 // edition: 2021
 
 pub async fn load() -> i32 {
diff --git a/tests/rustdoc/inline_cross/auxiliary/ret-pos-impl-trait-in-trait.rs b/tests/rustdoc/inline_cross/auxiliary/ret-pos-impl-trait-in-trait.rs
index c72f011152d..08a3f517671 100644
--- a/tests/rustdoc/inline_cross/auxiliary/ret-pos-impl-trait-in-trait.rs
+++ b/tests/rustdoc/inline_cross/auxiliary/ret-pos-impl-trait-in-trait.rs
@@ -1,5 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
-
 pub trait Trait {
     fn create() -> impl Iterator<Item = u64> {
         std::iter::empty()
diff --git a/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.current.stderr b/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.current.stderr
index b8be132e6b6..65f7a72fbff 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.current.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.current.stderr
@@ -25,7 +25,7 @@ LL | fn bar<T: Trait<method() -> (): Send>>() {}
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/bad-inputs-and-output.rs:5:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.next.stderr b/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.next.stderr
index b8be132e6b6..65f7a72fbff 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.next.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.next.stderr
@@ -25,7 +25,7 @@ LL | fn bar<T: Trait<method() -> (): Send>>() {}
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/bad-inputs-and-output.rs:5:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.rs b/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.rs
index 58ce41d1a89..4f332fa13d0 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.rs
+++ b/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.rs
@@ -1,6 +1,6 @@
 // edition: 2021
 
-#![feature(return_type_notation, async_fn_in_trait)]
+#![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete
 
 trait Trait {
diff --git a/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.stderr b/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.stderr
index 95ef7d82fca..1714dac12db 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/bad-inputs-and-output.stderr
@@ -25,7 +25,7 @@ LL | fn bar<T: Trait<method() -> (): Send>>() {}
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/bad-inputs-and-output.rs:3:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/basic.current_with.stderr b/tests/ui/associated-type-bounds/return-type-notation/basic.current_with.stderr
index 98c1a282779..c4dc5d36296 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/basic.current_with.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/basic.current_with.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/basic.rs:8:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/basic.current_without.stderr b/tests/ui/associated-type-bounds/return-type-notation/basic.current_without.stderr
index 1066c420c31..6c2645ae5bd 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/basic.current_without.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/basic.current_without.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/basic.rs:8:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/basic.next_with.stderr b/tests/ui/associated-type-bounds/return-type-notation/basic.next_with.stderr
index 98c1a282779..c4dc5d36296 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/basic.next_with.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/basic.next_with.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/basic.rs:8:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/basic.next_without.stderr b/tests/ui/associated-type-bounds/return-type-notation/basic.next_without.stderr
index 1066c420c31..6c2645ae5bd 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/basic.next_without.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/basic.next_without.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/basic.rs:8:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/basic.rs b/tests/ui/associated-type-bounds/return-type-notation/basic.rs
index 3dd9249a791..7f0647534f2 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/basic.rs
+++ b/tests/ui/associated-type-bounds/return-type-notation/basic.rs
@@ -2,7 +2,7 @@
 // edition: 2021
 // [with] check-pass
 
-#![feature(return_type_notation, async_fn_in_trait)]
+#![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete
 
 trait Foo {
diff --git a/tests/ui/associated-type-bounds/return-type-notation/basic.with.stderr b/tests/ui/associated-type-bounds/return-type-notation/basic.with.stderr
index 9962f4706b3..9d4bb356caa 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/basic.with.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/basic.with.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/basic.rs:5:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/basic.without.stderr b/tests/ui/associated-type-bounds/return-type-notation/basic.without.stderr
index edce1045e24..5b96676d037 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/basic.without.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/basic.without.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/basic.rs:5:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/equality.current.stderr b/tests/ui/associated-type-bounds/return-type-notation/equality.current.stderr
index b631dd0ebb5..d2a445f3387 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/equality.current.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/equality.current.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/equality.rs:5:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/equality.next.stderr b/tests/ui/associated-type-bounds/return-type-notation/equality.next.stderr
index b631dd0ebb5..d2a445f3387 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/equality.next.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/equality.next.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/equality.rs:5:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/equality.rs b/tests/ui/associated-type-bounds/return-type-notation/equality.rs
index 6884305d7b3..d5a29616ac5 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/equality.rs
+++ b/tests/ui/associated-type-bounds/return-type-notation/equality.rs
@@ -1,6 +1,6 @@
 // edition: 2021
 
-#![feature(return_type_notation, async_fn_in_trait)]
+#![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete
 
 use std::future::Future;
diff --git a/tests/ui/associated-type-bounds/return-type-notation/equality.stderr b/tests/ui/associated-type-bounds/return-type-notation/equality.stderr
index 490bfdc4c3c..1a2f8471524 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/equality.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/equality.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/equality.rs:3:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/associated-type-bounds/return-type-notation/missing.rs b/tests/ui/associated-type-bounds/return-type-notation/missing.rs
index a52562d78f8..0679b96f6c5 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/missing.rs
+++ b/tests/ui/associated-type-bounds/return-type-notation/missing.rs
@@ -1,6 +1,6 @@
 // edition: 2021
 
-#![feature(return_type_notation, async_fn_in_trait)]
+#![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete
 
 trait Trait {
diff --git a/tests/ui/associated-type-bounds/return-type-notation/missing.stderr b/tests/ui/associated-type-bounds/return-type-notation/missing.stderr
index 5b1c4cb0b2c..fb6538fa05c 100644
--- a/tests/ui/associated-type-bounds/return-type-notation/missing.stderr
+++ b/tests/ui/associated-type-bounds/return-type-notation/missing.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/missing.rs:3:12
    |
-LL | #![feature(return_type_notation, async_fn_in_trait)]
+LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/async-await/async-trait-fn.current.stderr b/tests/ui/async-await/async-trait-fn.current.stderr
deleted file mode 100644
index 7ccf2f2301d..00000000000
--- a/tests/ui/async-await/async-trait-fn.current.stderr
+++ /dev/null
@@ -1,42 +0,0 @@
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:6:5
-   |
-LL |     async fn foo() {}
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:7:5
-   |
-LL |     async fn bar(&self) {}
-   |     -----^^^^^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:8:5
-   |
-LL |     async fn baz() {
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0706`.
diff --git a/tests/ui/async-await/async-trait-fn.next.stderr b/tests/ui/async-await/async-trait-fn.next.stderr
deleted file mode 100644
index 7ccf2f2301d..00000000000
--- a/tests/ui/async-await/async-trait-fn.next.stderr
+++ /dev/null
@@ -1,42 +0,0 @@
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:6:5
-   |
-LL |     async fn foo() {}
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:7:5
-   |
-LL |     async fn bar(&self) {}
-   |     -----^^^^^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:8:5
-   |
-LL |     async fn baz() {
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0706`.
diff --git a/tests/ui/async-await/async-trait-fn.rs b/tests/ui/async-await/async-trait-fn.rs
index 04123badb53..4e5e3ba83e4 100644
--- a/tests/ui/async-await/async-trait-fn.rs
+++ b/tests/ui/async-await/async-trait-fn.rs
@@ -1,9 +1,10 @@
 // edition:2018
+// check-pass
 
 trait T {
-    async fn foo() {} //~ ERROR functions in traits cannot be declared `async`
-    async fn bar(&self) {} //~ ERROR functions in traits cannot be declared `async`
-    async fn baz() { //~ ERROR functions in traits cannot be declared `async`
+    async fn foo() {}
+    async fn bar(&self) {}
+    async fn baz() {
         // Nested item must not ICE.
         fn a() {}
     }
diff --git a/tests/ui/async-await/async-trait-fn.stderr b/tests/ui/async-await/async-trait-fn.stderr
deleted file mode 100644
index 68ebe3507ac..00000000000
--- a/tests/ui/async-await/async-trait-fn.stderr
+++ /dev/null
@@ -1,42 +0,0 @@
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:4:5
-   |
-LL |     async fn foo() {}
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:5:5
-   |
-LL |     async fn bar(&self) {}
-   |     -----^^^^^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/async-trait-fn.rs:6:5
-   |
-LL |     async fn baz() {
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0706`.
diff --git a/tests/ui/async-await/edition-deny-async-fns-2015.current.stderr b/tests/ui/async-await/edition-deny-async-fns-2015.current.stderr
deleted file mode 100644
index c47b99e657e..00000000000
--- a/tests/ui/async-await/edition-deny-async-fns-2015.current.stderr
+++ /dev/null
@@ -1,98 +0,0 @@
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:5:1
-   |
-LL | async fn foo() {}
-   | ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:7:12
-   |
-LL | fn baz() { async fn foo() {} }
-   |            ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:9:1
-   |
-LL | async fn async_baz() {
-   | ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:10:5
-   |
-LL |     async fn bar() {}
-   |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:16:5
-   |
-LL |     async fn foo() {}
-   |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:20:5
-   |
-LL |     async fn foo() {}
-   |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:38:9
-   |
-LL |         async fn bar() {}
-   |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:28:9
-   |
-LL |         async fn foo() {}
-   |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:33:13
-   |
-LL |             async fn bar() {}
-   |             ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/edition-deny-async-fns-2015.rs:20:5
-   |
-LL |     async fn foo() {}
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 10 previous errors
-
-Some errors have detailed explanations: E0670, E0706.
-For more information about an error, try `rustc --explain E0670`.
diff --git a/tests/ui/async-await/edition-deny-async-fns-2015.next.stderr b/tests/ui/async-await/edition-deny-async-fns-2015.next.stderr
deleted file mode 100644
index c47b99e657e..00000000000
--- a/tests/ui/async-await/edition-deny-async-fns-2015.next.stderr
+++ /dev/null
@@ -1,98 +0,0 @@
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:5:1
-   |
-LL | async fn foo() {}
-   | ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:7:12
-   |
-LL | fn baz() { async fn foo() {} }
-   |            ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:9:1
-   |
-LL | async fn async_baz() {
-   | ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:10:5
-   |
-LL |     async fn bar() {}
-   |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:16:5
-   |
-LL |     async fn foo() {}
-   |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:20:5
-   |
-LL |     async fn foo() {}
-   |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:38:9
-   |
-LL |         async fn bar() {}
-   |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:28:9
-   |
-LL |         async fn foo() {}
-   |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:33:13
-   |
-LL |             async fn bar() {}
-   |             ^^^^^ to use `async fn`, switch to Rust 2018 or later
-   |
-   = help: pass `--edition 2021` to `rustc`
-   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/edition-deny-async-fns-2015.rs:20:5
-   |
-LL |     async fn foo() {}
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 10 previous errors
-
-Some errors have detailed explanations: E0670, E0706.
-For more information about an error, try `rustc --explain E0670`.
diff --git a/tests/ui/async-await/edition-deny-async-fns-2015.rs b/tests/ui/async-await/edition-deny-async-fns-2015.rs
index 6bd6d879a4a..9059f99ba66 100644
--- a/tests/ui/async-await/edition-deny-async-fns-2015.rs
+++ b/tests/ui/async-await/edition-deny-async-fns-2015.rs
@@ -16,7 +16,6 @@ impl Foo {
 
 trait Bar {
     async fn foo() {} //~ ERROR `async fn` is not permitted in Rust 2015
-    //~^ ERROR functions in traits cannot be declared `async`
 }
 
 fn main() {
diff --git a/tests/ui/async-await/edition-deny-async-fns-2015.stderr b/tests/ui/async-await/edition-deny-async-fns-2015.stderr
index ba918eb28de..c40cdc5acec 100644
--- a/tests/ui/async-await/edition-deny-async-fns-2015.stderr
+++ b/tests/ui/async-await/edition-deny-async-fns-2015.stderr
@@ -53,7 +53,7 @@ LL |     async fn foo() {}
    = note: for more on editions, read https://doc.rust-lang.org/edition-guide
 
 error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:36:9
+  --> $DIR/edition-deny-async-fns-2015.rs:35:9
    |
 LL |         async fn bar() {}
    |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
@@ -62,7 +62,7 @@ LL |         async fn bar() {}
    = note: for more on editions, read https://doc.rust-lang.org/edition-guide
 
 error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:26:9
+  --> $DIR/edition-deny-async-fns-2015.rs:25:9
    |
 LL |         async fn foo() {}
    |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
@@ -71,7 +71,7 @@ LL |         async fn foo() {}
    = note: for more on editions, read https://doc.rust-lang.org/edition-guide
 
 error[E0670]: `async fn` is not permitted in Rust 2015
-  --> $DIR/edition-deny-async-fns-2015.rs:31:13
+  --> $DIR/edition-deny-async-fns-2015.rs:30:13
    |
 LL |             async fn bar() {}
    |             ^^^^^ to use `async fn`, switch to Rust 2018 or later
@@ -79,20 +79,6 @@ LL |             async fn bar() {}
    = help: pass `--edition 2021` to `rustc`
    = note: for more on editions, read https://doc.rust-lang.org/edition-guide
 
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/edition-deny-async-fns-2015.rs:18:5
-   |
-LL |     async fn foo() {}
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 10 previous errors
+error: aborting due to 9 previous errors
 
-Some errors have detailed explanations: E0670, E0706.
-For more information about an error, try `rustc --explain E0670`.
+For more information about this error, try `rustc --explain E0670`.
diff --git a/tests/ui/async-await/feature-gate-async_fn_in_trait.rs b/tests/ui/async-await/feature-gate-async_fn_in_trait.rs
deleted file mode 100644
index 792f378cb57..00000000000
--- a/tests/ui/async-await/feature-gate-async_fn_in_trait.rs
+++ /dev/null
@@ -1,25 +0,0 @@
-// edition:2021
-
-// RPITIT is not enough to allow use of async functions
-#![allow(incomplete_features)]
-#![feature(return_position_impl_trait_in_trait)]
-
-trait T {
-    async fn foo(); //~ ERROR functions in traits cannot be declared `async`
-}
-
-// Both return_position_impl_trait_in_trait and async_fn_in_trait are required for this (see also
-// feature-gate-return_position_impl_trait_in_trait.rs)
-trait T2 {
-    async fn foo() -> impl Sized; //~ ERROR functions in traits cannot be declared `async`
-}
-
-trait T3 {
-    fn foo() -> impl std::future::Future<Output = ()>;
-}
-
-impl T3 for () {
-    async fn foo() {} //~ ERROR functions in traits cannot be declared `async`
-}
-
-fn main() {}
diff --git a/tests/ui/async-await/feature-gate-async_fn_in_trait.stderr b/tests/ui/async-await/feature-gate-async_fn_in_trait.stderr
deleted file mode 100644
index 2a5fbd1ecd0..00000000000
--- a/tests/ui/async-await/feature-gate-async_fn_in_trait.stderr
+++ /dev/null
@@ -1,42 +0,0 @@
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/feature-gate-async_fn_in_trait.rs:8:5
-   |
-LL |     async fn foo();
-   |     -----^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/feature-gate-async_fn_in_trait.rs:14:5
-   |
-LL |     async fn foo() -> impl Sized;
-   |     -----^^^^^^^^^^^^^^^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/feature-gate-async_fn_in_trait.rs:22:5
-   |
-LL |     async fn foo() {}
-   |     -----^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0706`.
diff --git a/tests/ui/async-await/in-trait/async-associated-types.rs b/tests/ui/async-await/in-trait/async-associated-types.rs
index 14f18811c1e..8d89500477b 100644
--- a/tests/ui/async-await/in-trait/async-associated-types.rs
+++ b/tests/ui/async-await/in-trait/async-associated-types.rs
@@ -1,9 +1,6 @@
 // check-pass
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
-#![allow(incomplete_features)]
-
 use std::fmt::Debug;
 
 trait MyTrait<'a, 'b, T> where Self: 'a, T: Debug + Sized + 'b {
diff --git a/tests/ui/async-await/in-trait/async-default-fn-overridden.rs b/tests/ui/async-await/in-trait/async-default-fn-overridden.rs
index 8143f0bca03..c8fd2d8f6c2 100644
--- a/tests/ui/async-await/in-trait/async-default-fn-overridden.rs
+++ b/tests/ui/async-await/in-trait/async-default-fn-overridden.rs
@@ -1,7 +1,6 @@
 // run-pass
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 
 use std::future::Future;
 
diff --git a/tests/ui/async-await/in-trait/async-example-desugared-boxed-in-trait.rs b/tests/ui/async-await/in-trait/async-example-desugared-boxed-in-trait.rs
index 38ba297189c..3cc11d241f7 100644
--- a/tests/ui/async-await/in-trait/async-example-desugared-boxed-in-trait.rs
+++ b/tests/ui/async-await/in-trait/async-example-desugared-boxed-in-trait.rs
@@ -1,7 +1,5 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/tests/ui/async-await/in-trait/async-example-desugared-boxed-in-trait.stderr b/tests/ui/async-await/in-trait/async-example-desugared-boxed-in-trait.stderr
index 3f1f1766eb5..e6dd83b6b0a 100644
--- a/tests/ui/async-await/in-trait/async-example-desugared-boxed-in-trait.stderr
+++ b/tests/ui/async-await/in-trait/async-example-desugared-boxed-in-trait.stderr
@@ -1,11 +1,11 @@
 error[E0053]: method `foo` has an incompatible type for trait
-  --> $DIR/async-example-desugared-boxed-in-trait.rs:15:5
+  --> $DIR/async-example-desugared-boxed-in-trait.rs:13:5
    |
 LL |     async fn foo(&self) -> i32 {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `Pin<Box<dyn Future<Output = i32>>>`, found future
    |
 note: type in trait
-  --> $DIR/async-example-desugared-boxed-in-trait.rs:11:22
+  --> $DIR/async-example-desugared-boxed-in-trait.rs:9:22
    |
 LL |     fn foo(&self) -> Pin<Box<dyn Future<Output = i32> + '_>>;
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/async-await/in-trait/async-example-desugared-boxed.rs b/tests/ui/async-await/in-trait/async-example-desugared-boxed.rs
index 1b1b3cffd58..81d25ce27ae 100644
--- a/tests/ui/async-await/in-trait/async-example-desugared-boxed.rs
+++ b/tests/ui/async-await/in-trait/async-example-desugared-boxed.rs
@@ -1,7 +1,5 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/tests/ui/async-await/in-trait/async-example-desugared-boxed.stderr b/tests/ui/async-await/in-trait/async-example-desugared-boxed.stderr
index 60fa534a64f..cd18790fdfb 100644
--- a/tests/ui/async-await/in-trait/async-example-desugared-boxed.stderr
+++ b/tests/ui/async-await/in-trait/async-example-desugared-boxed.stderr
@@ -1,5 +1,5 @@
 error: method `foo` should be async because the method from the trait is async
-  --> $DIR/async-example-desugared-boxed.rs:15:5
+  --> $DIR/async-example-desugared-boxed.rs:13:5
    |
 LL |     async fn foo(&self) -> i32;
    |     --------------------------- required because the trait method is async
diff --git a/tests/ui/async-await/in-trait/async-example-desugared-extra.rs b/tests/ui/async-await/in-trait/async-example-desugared-extra.rs
index 5d5aa817b4c..f0c59180fb5 100644
--- a/tests/ui/async-await/in-trait/async-example-desugared-extra.rs
+++ b/tests/ui/async-await/in-trait/async-example-desugared-extra.rs
@@ -1,8 +1,7 @@
 // check-pass
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
-#![feature(return_position_impl_trait_in_trait, lint_reasons)]
+#![feature(lint_reasons)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/tests/ui/async-await/in-trait/async-example-desugared-in-trait.rs b/tests/ui/async-await/in-trait/async-example-desugared-in-trait.rs
index feeda719e03..deca28af853 100644
--- a/tests/ui/async-await/in-trait/async-example-desugared-in-trait.rs
+++ b/tests/ui/async-await/in-trait/async-example-desugared-in-trait.rs
@@ -1,8 +1,6 @@
 // check-pass
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/tests/ui/async-await/in-trait/async-example-desugared-manual.rs b/tests/ui/async-await/in-trait/async-example-desugared-manual.rs
index 71473e7455f..fdba4d93c77 100644
--- a/tests/ui/async-await/in-trait/async-example-desugared-manual.rs
+++ b/tests/ui/async-await/in-trait/async-example-desugared-manual.rs
@@ -1,7 +1,5 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/tests/ui/async-await/in-trait/async-example-desugared-manual.stderr b/tests/ui/async-await/in-trait/async-example-desugared-manual.stderr
index 567a36a86d1..463892f21bf 100644
--- a/tests/ui/async-await/in-trait/async-example-desugared-manual.stderr
+++ b/tests/ui/async-await/in-trait/async-example-desugared-manual.stderr
@@ -1,5 +1,5 @@
 error: method `foo` should be async because the method from the trait is async
-  --> $DIR/async-example-desugared-manual.rs:23:5
+  --> $DIR/async-example-desugared-manual.rs:21:5
    |
 LL |     async fn foo(&self) -> i32;
    |     --------------------------- required because the trait method is async
diff --git a/tests/ui/async-await/in-trait/async-example-desugared.rs b/tests/ui/async-await/in-trait/async-example-desugared.rs
index 7987645c97b..7fc78f7da6d 100644
--- a/tests/ui/async-await/in-trait/async-example-desugared.rs
+++ b/tests/ui/async-await/in-trait/async-example-desugared.rs
@@ -1,8 +1,6 @@
 // check-pass
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/tests/ui/async-await/in-trait/async-example.rs b/tests/ui/async-await/in-trait/async-example.rs
index 8c80c21eabe..62ed490bf05 100644
--- a/tests/ui/async-await/in-trait/async-example.rs
+++ b/tests/ui/async-await/in-trait/async-example.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 trait MyTrait {
diff --git a/tests/ui/async-await/in-trait/async-generics-and-bounds.rs b/tests/ui/async-await/in-trait/async-generics-and-bounds.rs
index a73d55adfec..4e859fb27a9 100644
--- a/tests/ui/async-await/in-trait/async-generics-and-bounds.rs
+++ b/tests/ui/async-await/in-trait/async-generics-and-bounds.rs
@@ -2,7 +2,6 @@
 // known-bug: #102682
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Debug;
diff --git a/tests/ui/async-await/in-trait/async-generics-and-bounds.stderr b/tests/ui/async-await/in-trait/async-generics-and-bounds.stderr
index 965c385e9bc..d7251a52863 100644
--- a/tests/ui/async-await/in-trait/async-generics-and-bounds.stderr
+++ b/tests/ui/async-await/in-trait/async-generics-and-bounds.stderr
@@ -1,5 +1,5 @@
 error[E0311]: the parameter type `U` may not live long enough
-  --> $DIR/async-generics-and-bounds.rs:12:5
+  --> $DIR/async-generics-and-bounds.rs:11:5
    |
 LL |     async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
    |     ^^^^^^^^^^^^^-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -13,7 +13,7 @@ LL |     async fn foo<'a>(&'a self) -> &'a (T, U) where T: Debug + Sized, U: Has
    |                 ++++  ++           ++                                       +++++++
 
 error[E0311]: the parameter type `T` may not live long enough
-  --> $DIR/async-generics-and-bounds.rs:12:5
+  --> $DIR/async-generics-and-bounds.rs:11:5
    |
 LL |     async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
    |     ^^^^^^^^^^^^^-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/async-await/in-trait/async-generics.rs b/tests/ui/async-await/in-trait/async-generics.rs
index 67000e5770e..2d342592848 100644
--- a/tests/ui/async-await/in-trait/async-generics.rs
+++ b/tests/ui/async-await/in-trait/async-generics.rs
@@ -2,7 +2,6 @@
 // known-bug: #102682
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 trait MyTrait<T, U> {
diff --git a/tests/ui/async-await/in-trait/async-generics.stderr b/tests/ui/async-await/in-trait/async-generics.stderr
index 20c2491e9d0..aec62d12201 100644
--- a/tests/ui/async-await/in-trait/async-generics.stderr
+++ b/tests/ui/async-await/in-trait/async-generics.stderr
@@ -1,5 +1,5 @@
 error[E0311]: the parameter type `U` may not live long enough
-  --> $DIR/async-generics.rs:9:5
+  --> $DIR/async-generics.rs:8:5
    |
 LL |     async fn foo(&self) -> &(T, U);
    |     ^^^^^^^^^^^^^-^^^^^^^^^^^^^^^^^
@@ -13,7 +13,7 @@ LL |     async fn foo<'a>(&'a self) -> &'a (T, U) where U: 'a;
    |                 ++++  ++           ++        +++++++++++
 
 error[E0311]: the parameter type `T` may not live long enough
-  --> $DIR/async-generics.rs:9:5
+  --> $DIR/async-generics.rs:8:5
    |
 LL |     async fn foo(&self) -> &(T, U);
    |     ^^^^^^^^^^^^^-^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/async-await/in-trait/async-lifetimes-and-bounds.rs b/tests/ui/async-await/in-trait/async-lifetimes-and-bounds.rs
index 96cda4e35da..ea8330a4b52 100644
--- a/tests/ui/async-await/in-trait/async-lifetimes-and-bounds.rs
+++ b/tests/ui/async-await/in-trait/async-lifetimes-and-bounds.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Debug;
diff --git a/tests/ui/async-await/in-trait/async-lifetimes.rs b/tests/ui/async-await/in-trait/async-lifetimes.rs
index 4b0264bc8d0..6e573b9cc8b 100644
--- a/tests/ui/async-await/in-trait/async-lifetimes.rs
+++ b/tests/ui/async-await/in-trait/async-lifetimes.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 trait MyTrait<'a, 'b, T> {
diff --git a/tests/ui/async-await/in-trait/async-recursive-generic.rs b/tests/ui/async-await/in-trait/async-recursive-generic.rs
index 6839abd381c..34f1b09756e 100644
--- a/tests/ui/async-await/in-trait/async-recursive-generic.rs
+++ b/tests/ui/async-await/in-trait/async-recursive-generic.rs
@@ -1,6 +1,5 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 trait MyTrait<T> {
diff --git a/tests/ui/async-await/in-trait/async-recursive-generic.stderr b/tests/ui/async-await/in-trait/async-recursive-generic.stderr
index 6897bf1c999..7c2df6683f0 100644
--- a/tests/ui/async-await/in-trait/async-recursive-generic.stderr
+++ b/tests/ui/async-await/in-trait/async-recursive-generic.stderr
@@ -1,5 +1,5 @@
 error[E0733]: recursion in an `async fn` requires boxing
-  --> $DIR/async-recursive-generic.rs:11:5
+  --> $DIR/async-recursive-generic.rs:10:5
    |
 LL |     async fn foo_recursive(&self, n: usize) -> T {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ recursive `async fn`
diff --git a/tests/ui/async-await/in-trait/async-recursive.rs b/tests/ui/async-await/in-trait/async-recursive.rs
index 61119f8095b..ddf119b252f 100644
--- a/tests/ui/async-await/in-trait/async-recursive.rs
+++ b/tests/ui/async-await/in-trait/async-recursive.rs
@@ -1,6 +1,5 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 trait MyTrait {
diff --git a/tests/ui/async-await/in-trait/async-recursive.stderr b/tests/ui/async-await/in-trait/async-recursive.stderr
index c9b4784e3b4..1253252cc40 100644
--- a/tests/ui/async-await/in-trait/async-recursive.stderr
+++ b/tests/ui/async-await/in-trait/async-recursive.stderr
@@ -1,5 +1,5 @@
 error[E0733]: recursion in an `async fn` requires boxing
-  --> $DIR/async-recursive.rs:11:5
+  --> $DIR/async-recursive.rs:10:5
    |
 LL |     async fn foo_recursive(&self, n: usize) -> i32 {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ recursive `async fn`
diff --git a/tests/ui/async-await/in-trait/auxiliary/foreign-async-fn.rs b/tests/ui/async-await/in-trait/auxiliary/foreign-async-fn.rs
index bba886f175e..57c9b3ae8b3 100644
--- a/tests/ui/async-await/in-trait/auxiliary/foreign-async-fn.rs
+++ b/tests/ui/async-await/in-trait/auxiliary/foreign-async-fn.rs
@@ -1,7 +1,5 @@
 // edition:2021
 
-#![feature(async_fn_in_trait)]
-
 pub trait Foo {
     async fn test();
 }
diff --git a/tests/ui/async-await/in-trait/bad-signatures.rs b/tests/ui/async-await/in-trait/bad-signatures.rs
index 98dddc126c5..5adede5b5cf 100644
--- a/tests/ui/async-await/in-trait/bad-signatures.rs
+++ b/tests/ui/async-await/in-trait/bad-signatures.rs
@@ -1,6 +1,5 @@
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 
 trait MyTrait {
     async fn bar(&abc self);
diff --git a/tests/ui/async-await/in-trait/bad-signatures.stderr b/tests/ui/async-await/in-trait/bad-signatures.stderr
index 7cbd96e2487..127a343a930 100644
--- a/tests/ui/async-await/in-trait/bad-signatures.stderr
+++ b/tests/ui/async-await/in-trait/bad-signatures.stderr
@@ -1,11 +1,11 @@
 error: expected identifier, found keyword `self`
-  --> $DIR/bad-signatures.rs:6:23
+  --> $DIR/bad-signatures.rs:5:23
    |
 LL |     async fn bar(&abc self);
    |                       ^^^^ expected identifier, found keyword
 
 error: expected one of `:`, `@`, or `|`, found keyword `self`
-  --> $DIR/bad-signatures.rs:6:23
+  --> $DIR/bad-signatures.rs:5:23
    |
 LL |     async fn bar(&abc self);
    |                  -----^^^^
diff --git a/tests/ui/async-await/in-trait/dont-project-to-specializable-projection.rs b/tests/ui/async-await/in-trait/dont-project-to-specializable-projection.rs
index afd3db5e052..18b0fa4856d 100644
--- a/tests/ui/async-await/in-trait/dont-project-to-specializable-projection.rs
+++ b/tests/ui/async-await/in-trait/dont-project-to-specializable-projection.rs
@@ -1,7 +1,6 @@
 // edition: 2021
 // known-bug: #108309
 
-#![feature(async_fn_in_trait)]
 #![feature(min_specialization)]
 
 struct MyStruct;
diff --git a/tests/ui/async-await/in-trait/dont-project-to-specializable-projection.stderr b/tests/ui/async-await/in-trait/dont-project-to-specializable-projection.stderr
index 4ba6d4cba0c..5e2be08623b 100644
--- a/tests/ui/async-await/in-trait/dont-project-to-specializable-projection.stderr
+++ b/tests/ui/async-await/in-trait/dont-project-to-specializable-projection.stderr
@@ -1,11 +1,11 @@
 error[E0053]: method `foo` has an incompatible type for trait
-  --> $DIR/dont-project-to-specializable-projection.rs:14:5
+  --> $DIR/dont-project-to-specializable-projection.rs:13:5
    |
 LL |     default async fn foo(_: T) -> &'static str {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected associated type, found future
    |
 note: type in trait
-  --> $DIR/dont-project-to-specializable-projection.rs:10:5
+  --> $DIR/dont-project-to-specializable-projection.rs:9:5
    |
 LL |     async fn foo(_: T) -> &'static str;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -13,12 +13,12 @@ LL |     async fn foo(_: T) -> &'static str;
               found signature `fn(_) -> impl Future<Output = &'static str>`
 
 error: async associated function in trait cannot be specialized
-  --> $DIR/dont-project-to-specializable-projection.rs:14:5
+  --> $DIR/dont-project-to-specializable-projection.rs:13:5
    |
 LL |     default async fn foo(_: T) -> &'static str {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: specialization behaves in inconsistent and surprising ways with `#![feature(async_fn_in_trait)]`, and for now is disallowed
+   = note: specialization behaves in inconsistent and surprising ways with async functions in traits, and for now is disallowed
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/async-await/in-trait/early-bound-1.rs b/tests/ui/async-await/in-trait/early-bound-1.rs
index bc410cc2954..f79d6f23c93 100644
--- a/tests/ui/async-await/in-trait/early-bound-1.rs
+++ b/tests/ui/async-await/in-trait/early-bound-1.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 pub trait Foo {
diff --git a/tests/ui/async-await/in-trait/early-bound-2.rs b/tests/ui/async-await/in-trait/early-bound-2.rs
index 1974b1d9f7a..3eba5bf757f 100644
--- a/tests/ui/async-await/in-trait/early-bound-2.rs
+++ b/tests/ui/async-await/in-trait/early-bound-2.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 pub trait Foo {
diff --git a/tests/ui/async-await/in-trait/fn-not-async-err.rs b/tests/ui/async-await/in-trait/fn-not-async-err.rs
index 9598d53bce8..60077a7e00c 100644
--- a/tests/ui/async-await/in-trait/fn-not-async-err.rs
+++ b/tests/ui/async-await/in-trait/fn-not-async-err.rs
@@ -1,6 +1,5 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 trait MyTrait {
diff --git a/tests/ui/async-await/in-trait/fn-not-async-err.stderr b/tests/ui/async-await/in-trait/fn-not-async-err.stderr
index 579801d0f39..cd085074ae3 100644
--- a/tests/ui/async-await/in-trait/fn-not-async-err.stderr
+++ b/tests/ui/async-await/in-trait/fn-not-async-err.stderr
@@ -1,5 +1,5 @@
 error: method `foo` should be async because the method from the trait is async
-  --> $DIR/fn-not-async-err.rs:11:5
+  --> $DIR/fn-not-async-err.rs:10:5
    |
 LL |     async fn foo(&self) -> i32;
    |     --------------------------- required because the trait method is async
diff --git a/tests/ui/async-await/in-trait/fn-not-async-err2.rs b/tests/ui/async-await/in-trait/fn-not-async-err2.rs
index e1703415dbd..ed626edc4c4 100644
--- a/tests/ui/async-await/in-trait/fn-not-async-err2.rs
+++ b/tests/ui/async-await/in-trait/fn-not-async-err2.rs
@@ -1,6 +1,6 @@
 // edition: 2021
+// check-pass
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
@@ -11,7 +11,6 @@ trait MyTrait {
 
 impl MyTrait for i32 {
     fn foo(&self) -> impl Future<Output = i32> {
-        //~^ ERROR `impl Trait` only allowed in function and inherent method argument and return types, not in `impl` method return types
         async { *self }
     }
 }
diff --git a/tests/ui/async-await/in-trait/fn-not-async-err2.stderr b/tests/ui/async-await/in-trait/fn-not-async-err2.stderr
deleted file mode 100644
index a7c897f786e..00000000000
--- a/tests/ui/async-await/in-trait/fn-not-async-err2.stderr
+++ /dev/null
@@ -1,12 +0,0 @@
-error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in `impl` method return types
-  --> $DIR/fn-not-async-err2.rs:13:22
-   |
-LL |     fn foo(&self) -> impl Future<Output = i32> {
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0562`.
diff --git a/tests/ui/async-await/in-trait/generics-mismatch.rs b/tests/ui/async-await/in-trait/generics-mismatch.rs
index fc29783c0e3..51fdc2fe8a8 100644
--- a/tests/ui/async-await/in-trait/generics-mismatch.rs
+++ b/tests/ui/async-await/in-trait/generics-mismatch.rs
@@ -1,6 +1,5 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 trait Foo {
diff --git a/tests/ui/async-await/in-trait/generics-mismatch.stderr b/tests/ui/async-await/in-trait/generics-mismatch.stderr
index 3518aa05cec..647cc698f9f 100644
--- a/tests/ui/async-await/in-trait/generics-mismatch.stderr
+++ b/tests/ui/async-await/in-trait/generics-mismatch.stderr
@@ -1,5 +1,5 @@
 error[E0053]: method `foo` has an incompatible generic parameter for trait `Foo`
-  --> $DIR/generics-mismatch.rs:11:18
+  --> $DIR/generics-mismatch.rs:10:18
    |
 LL | trait Foo {
    |       ---
diff --git a/tests/ui/async-await/in-trait/implied-bounds.rs b/tests/ui/async-await/in-trait/implied-bounds.rs
index 40eebad86c2..0d8177c8e60 100644
--- a/tests/ui/async-await/in-trait/implied-bounds.rs
+++ b/tests/ui/async-await/in-trait/implied-bounds.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 trait TcpStack {
diff --git a/tests/ui/async-await/in-trait/indirect-recursion-issue-112047.rs b/tests/ui/async-await/in-trait/indirect-recursion-issue-112047.rs
index 2fe6b473df6..8443cbcf4ac 100644
--- a/tests/ui/async-await/in-trait/indirect-recursion-issue-112047.rs
+++ b/tests/ui/async-await/in-trait/indirect-recursion-issue-112047.rs
@@ -2,8 +2,6 @@
 // build-fail
 //~^^ ERROR cycle detected when computing layout of
 
-#![feature(async_fn_in_trait)]
-
 fn main() {
     let _ = async {
         A.first().await.second().await;
diff --git a/tests/ui/async-await/in-trait/indirect-recursion-issue-112047.stderr b/tests/ui/async-await/in-trait/indirect-recursion-issue-112047.stderr
index 41e84466a14..ce02c1e9967 100644
--- a/tests/ui/async-await/in-trait/indirect-recursion-issue-112047.stderr
+++ b/tests/ui/async-await/in-trait/indirect-recursion-issue-112047.stderr
@@ -1,8 +1,8 @@
-error[E0391]: cycle detected when computing layout of `{async fn body@$DIR/indirect-recursion-issue-112047.rs:35:27: 37:6}`
+error[E0391]: cycle detected when computing layout of `{async fn body@$DIR/indirect-recursion-issue-112047.rs:33:27: 35:6}`
    |
    = note: ...which requires computing layout of `<<A as First>::Second as Second>::{opaque#0}`...
-   = note: ...which again requires computing layout of `{async fn body@$DIR/indirect-recursion-issue-112047.rs:35:27: 37:6}`, completing the cycle
-   = note: cycle used when computing layout of `{async block@$DIR/indirect-recursion-issue-112047.rs:8:13: 10:6}`
+   = note: ...which again requires computing layout of `{async fn body@$DIR/indirect-recursion-issue-112047.rs:33:27: 35:6}`, completing the cycle
+   = note: cycle used when computing layout of `{async block@$DIR/indirect-recursion-issue-112047.rs:6:13: 8:6}`
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
 error: aborting due to previous error
diff --git a/tests/ui/async-await/in-trait/issue-102138.rs b/tests/ui/async-await/in-trait/issue-102138.rs
index 3d9cef0210f..221b830fc5f 100644
--- a/tests/ui/async-await/in-trait/issue-102138.rs
+++ b/tests/ui/async-await/in-trait/issue-102138.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/tests/ui/async-await/in-trait/issue-102219.rs b/tests/ui/async-await/in-trait/issue-102219.rs
index 4a23e4be4f7..1f32cf691eb 100644
--- a/tests/ui/async-await/in-trait/issue-102219.rs
+++ b/tests/ui/async-await/in-trait/issue-102219.rs
@@ -2,7 +2,6 @@
 // edition:2021
 // check-pass
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 trait T {
diff --git a/tests/ui/async-await/in-trait/issue-102310.rs b/tests/ui/async-await/in-trait/issue-102310.rs
index 327d432a6a6..c6321dfcbe8 100644
--- a/tests/ui/async-await/in-trait/issue-102310.rs
+++ b/tests/ui/async-await/in-trait/issue-102310.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 pub trait SpiDevice {
diff --git a/tests/ui/async-await/in-trait/issue-104678.rs b/tests/ui/async-await/in-trait/issue-104678.rs
index 0a334707505..db2fa3026fc 100644
--- a/tests/ui/async-await/in-trait/issue-104678.rs
+++ b/tests/ui/async-await/in-trait/issue-104678.rs
@@ -1,7 +1,6 @@
 // edition:2021
 // check-pass
 
-#![feature(async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/tests/ui/async-await/in-trait/lifetime-mismatch.rs b/tests/ui/async-await/in-trait/lifetime-mismatch.rs
index bb793df5d85..b45d1758da4 100644
--- a/tests/ui/async-await/in-trait/lifetime-mismatch.rs
+++ b/tests/ui/async-await/in-trait/lifetime-mismatch.rs
@@ -1,6 +1,5 @@
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 
 trait MyTrait {
     async fn foo<'a>(&self);
diff --git a/tests/ui/async-await/in-trait/lifetime-mismatch.stderr b/tests/ui/async-await/in-trait/lifetime-mismatch.stderr
index 86592269c02..3841ab9345f 100644
--- a/tests/ui/async-await/in-trait/lifetime-mismatch.stderr
+++ b/tests/ui/async-await/in-trait/lifetime-mismatch.stderr
@@ -1,5 +1,5 @@
 error[E0195]: lifetime parameters or bounds on method `foo` do not match the trait declaration
-  --> $DIR/lifetime-mismatch.rs:11:17
+  --> $DIR/lifetime-mismatch.rs:10:17
    |
 LL |     async fn foo<'a>(&self);
    |                 ---- lifetimes in impl do not match this method in trait
diff --git a/tests/ui/async-await/in-trait/missing-feature-flag.rs b/tests/ui/async-await/in-trait/missing-feature-flag.rs
index 34dd50a1c30..898299a7d9d 100644
--- a/tests/ui/async-await/in-trait/missing-feature-flag.rs
+++ b/tests/ui/async-await/in-trait/missing-feature-flag.rs
@@ -1,6 +1,5 @@
 // edition:2018
 
-#![feature(async_fn_in_trait)]
 #![feature(min_specialization)]
 
 struct MyStruct;
diff --git a/tests/ui/async-await/in-trait/missing-feature-flag.stderr b/tests/ui/async-await/in-trait/missing-feature-flag.stderr
index 87a7e85bfbb..b7a9e98fc49 100644
--- a/tests/ui/async-await/in-trait/missing-feature-flag.stderr
+++ b/tests/ui/async-await/in-trait/missing-feature-flag.stderr
@@ -1,5 +1,5 @@
 error[E0046]: not all trait items implemented, missing: `foo`
-  --> $DIR/missing-feature-flag.rs:12:1
+  --> $DIR/missing-feature-flag.rs:11:1
    |
 LL |     async fn foo(_: T) -> &'static str;
    |     ----------------------------------- `foo` from trait
@@ -8,13 +8,13 @@ LL | impl<T> MyTrait<T> for MyStruct {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `foo` in implementation
 
 error[E0308]: mismatched types
-  --> $DIR/missing-feature-flag.rs:16:42
+  --> $DIR/missing-feature-flag.rs:15:42
    |
 LL |     async fn foo(_: i32) -> &'static str {}
    |                                          ^^ expected `&str`, found `()`
 
 error[E0520]: `foo` specializes an item from a parent `impl`, but that item is not marked `default`
-  --> $DIR/missing-feature-flag.rs:16:5
+  --> $DIR/missing-feature-flag.rs:15:5
    |
 LL | impl<T> MyTrait<T> for MyStruct {}
    | ------------------------------- parent `impl` is here
diff --git a/tests/ui/async-await/in-trait/missing-send-bound.rs b/tests/ui/async-await/in-trait/missing-send-bound.rs
index dbcc6657618..596aece748d 100644
--- a/tests/ui/async-await/in-trait/missing-send-bound.rs
+++ b/tests/ui/async-await/in-trait/missing-send-bound.rs
@@ -1,6 +1,5 @@
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 
 trait Foo {
     async fn bar();
diff --git a/tests/ui/async-await/in-trait/missing-send-bound.stderr b/tests/ui/async-await/in-trait/missing-send-bound.stderr
index 7e59d94d456..139bd06c7df 100644
--- a/tests/ui/async-await/in-trait/missing-send-bound.stderr
+++ b/tests/ui/async-await/in-trait/missing-send-bound.stderr
@@ -1,17 +1,17 @@
 error: future cannot be sent between threads safely
-  --> $DIR/missing-send-bound.rs:14:20
+  --> $DIR/missing-send-bound.rs:13:20
    |
 LL |     assert_is_send(test::<T>());
    |                    ^^^^^^^^^^^ future returned by `test` is not `Send`
    |
    = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `impl Future<Output = ()>`
 note: future is not `Send` as it awaits another future which is not `Send`
-  --> $DIR/missing-send-bound.rs:10:5
+  --> $DIR/missing-send-bound.rs:9:5
    |
 LL |     T::bar().await;
    |     ^^^^^^^^ await occurs here on type `impl Future<Output = ()>`, which is not `Send`
 note: required by a bound in `assert_is_send`
-  --> $DIR/missing-send-bound.rs:18:27
+  --> $DIR/missing-send-bound.rs:17:27
    |
 LL | fn assert_is_send(_: impl Send) {}
    |                           ^^^^ required by this bound in `assert_is_send`
diff --git a/tests/ui/async-await/in-trait/nested-rpit.rs b/tests/ui/async-await/in-trait/nested-rpit.rs
index 8c43e1b07e2..ccae08accb6 100644
--- a/tests/ui/async-await/in-trait/nested-rpit.rs
+++ b/tests/ui/async-await/in-trait/nested-rpit.rs
@@ -1,8 +1,6 @@
 // edition: 2021
 // check-pass
 
-#![feature(async_fn_in_trait)]
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::future::Future;
diff --git a/tests/ui/async-await/in-trait/normalize-opaque-with-bound-vars.rs b/tests/ui/async-await/in-trait/normalize-opaque-with-bound-vars.rs
index f8fe0d1bde8..9eb396f3202 100644
--- a/tests/ui/async-await/in-trait/normalize-opaque-with-bound-vars.rs
+++ b/tests/ui/async-await/in-trait/normalize-opaque-with-bound-vars.rs
@@ -5,7 +5,6 @@
 // We were not normalizing opaques with escaping bound vars during codegen,
 // leading to later errors during debuginfo computation.
 
-#![feature(async_fn_in_trait)]
 
 #[derive(Clone, Copy)]
 pub struct SharedState {}
diff --git a/tests/ui/async-await/in-trait/object-safety.rs b/tests/ui/async-await/in-trait/object-safety.rs
index 441539e5dd4..5e5375b082b 100644
--- a/tests/ui/async-await/in-trait/object-safety.rs
+++ b/tests/ui/async-await/in-trait/object-safety.rs
@@ -1,6 +1,5 @@
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 
 trait Foo {
     async fn foo(&self);
diff --git a/tests/ui/async-await/in-trait/object-safety.stderr b/tests/ui/async-await/in-trait/object-safety.stderr
index ccdf9d88708..5b9fd98ac60 100644
--- a/tests/ui/async-await/in-trait/object-safety.stderr
+++ b/tests/ui/async-await/in-trait/object-safety.stderr
@@ -1,11 +1,11 @@
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety.rs:10:12
+  --> $DIR/object-safety.rs:9:12
    |
 LL |     let x: &dyn Foo = todo!();
    |            ^^^^^^^^ `Foo` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/object-safety.rs:6:14
+  --> $DIR/object-safety.rs:5:14
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
diff --git a/tests/ui/async-await/in-trait/return-not-existing-pair.rs b/tests/ui/async-await/in-trait/return-not-existing-pair.rs
index a14dfceed75..2286316dd88 100644
--- a/tests/ui/async-await/in-trait/return-not-existing-pair.rs
+++ b/tests/ui/async-await/in-trait/return-not-existing-pair.rs
@@ -1,6 +1,5 @@
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 
 trait MyTrait<'a, 'b, T> {
     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
diff --git a/tests/ui/async-await/in-trait/return-not-existing-pair.stderr b/tests/ui/async-await/in-trait/return-not-existing-pair.stderr
index e573b851706..4694e608097 100644
--- a/tests/ui/async-await/in-trait/return-not-existing-pair.stderr
+++ b/tests/ui/async-await/in-trait/return-not-existing-pair.stderr
@@ -1,5 +1,5 @@
 error[E0726]: implicit elided lifetime not allowed here
-  --> $DIR/return-not-existing-pair.rs:10:20
+  --> $DIR/return-not-existing-pair.rs:9:20
    |
 LL | impl<'a, 'b, T, U> MyTrait<T> for U {
    |                    ^^^^^^^^^^ expected lifetime parameters
@@ -10,13 +10,13 @@ LL | impl<'a, 'b, T, U> MyTrait<'_, '_, T> for U {
    |                            +++++++
 
 error[E0412]: cannot find type `ConnImpl` in this scope
-  --> $DIR/return-not-existing-pair.rs:6:48
+  --> $DIR/return-not-existing-pair.rs:5:48
    |
 LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
    |                                                ^^^^^^^^ not found in this scope
 
 error[E0186]: method `foo` has a `&self` declaration in the trait, but not in the impl
-  --> $DIR/return-not-existing-pair.rs:12:5
+  --> $DIR/return-not-existing-pair.rs:11:5
    |
 LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
    |     ------------------------------------------------------------ `&self` used in trait
@@ -25,7 +25,7 @@ LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&self` in impl
 
 error[E0308]: mismatched types
-  --> $DIR/return-not-existing-pair.rs:12:42
+  --> $DIR/return-not-existing-pair.rs:11:42
    |
 LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
    |                                          ^^ expected `(&U, &T)`, found `()`
diff --git a/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.rs b/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.rs
index 254b9a7824f..d23ef093be1 100644
--- a/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.rs
+++ b/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.rs
@@ -1,6 +1,5 @@
 // edition:2021
 
-#![feature(return_position_impl_trait_in_trait)]
 
 struct Wrapper<T>(T);
 
diff --git a/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.stderr b/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.stderr
index 059934d245c..a66dd13bb7a 100644
--- a/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.stderr
+++ b/tests/ui/async-await/in-trait/return-not-existing-type-wrapping-rpitit.stderr
@@ -1,5 +1,5 @@
 error[E0412]: cannot find type `Missing` in this scope
-  --> $DIR/return-not-existing-type-wrapping-rpitit.rs:8:25
+  --> $DIR/return-not-existing-type-wrapping-rpitit.rs:7:25
    |
 LL |     fn bar() -> Wrapper<Missing<impl Sized>>;
    |                         ^^^^^^^ not found in this scope
diff --git a/tests/ui/async-await/in-trait/return-type-suggestion.rs b/tests/ui/async-await/in-trait/return-type-suggestion.rs
index cdab4ea0f37..2b19b24cf7a 100644
--- a/tests/ui/async-await/in-trait/return-type-suggestion.rs
+++ b/tests/ui/async-await/in-trait/return-type-suggestion.rs
@@ -1,6 +1,5 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 
 trait A {
     async fn e() {
diff --git a/tests/ui/async-await/in-trait/return-type-suggestion.stderr b/tests/ui/async-await/in-trait/return-type-suggestion.stderr
index 179c9ed93db..363870619f0 100644
--- a/tests/ui/async-await/in-trait/return-type-suggestion.stderr
+++ b/tests/ui/async-await/in-trait/return-type-suggestion.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/return-type-suggestion.rs:7:9
+  --> $DIR/return-type-suggestion.rs:6:9
    |
 LL |         Ok(())
    |         ^^^^^^ expected `()`, found `Result<(), _>`
diff --git a/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.fixed b/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.fixed
index 33c00587439..affe6cded8f 100644
--- a/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.fixed
+++ b/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.fixed
@@ -1,7 +1,6 @@
 // run-rustfix
 // edition: 2021
 
-#![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
 #![allow(unused)]
 
 trait Foo {
diff --git a/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.rs b/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.rs
index 96b623d6988..02bfee1a25f 100644
--- a/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.rs
+++ b/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.rs
@@ -1,7 +1,6 @@
 // run-rustfix
 // edition: 2021
 
-#![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
 #![allow(unused)]
 
 trait Foo {
diff --git a/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.stderr b/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.stderr
index 4319a14118b..da51f10af94 100644
--- a/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.stderr
+++ b/tests/ui/async-await/in-trait/send-on-async-fn-in-trait.stderr
@@ -1,5 +1,5 @@
 error[E0277]: `impl Future<Output = ()>` cannot be sent between threads safely
-  --> $DIR/send-on-async-fn-in-trait.rs:14:16
+  --> $DIR/send-on-async-fn-in-trait.rs:13:16
    |
 LL |     needs_send(T::test());
    |     ---------- ^^^^^^^^^ `impl Future<Output = ()>` cannot be sent between threads safely
@@ -8,7 +8,7 @@ LL |     needs_send(T::test());
    |
    = help: the trait `Send` is not implemented for `impl Future<Output = ()>`
 note: required by a bound in `needs_send`
-  --> $DIR/send-on-async-fn-in-trait.rs:13:27
+  --> $DIR/send-on-async-fn-in-trait.rs:12:27
    |
 LL |     fn needs_send(_: impl Send) {}
    |                           ^^^^ required by this bound in `needs_send`
@@ -19,7 +19,7 @@ LL +     fn test() -> impl std::future::Future<Output = ()> + Send { async {} }
    |
 
 error[E0277]: `impl Future<Output = i32>` cannot be sent between threads safely
-  --> $DIR/send-on-async-fn-in-trait.rs:16:16
+  --> $DIR/send-on-async-fn-in-trait.rs:15:16
    |
 LL |     needs_send(T::test2());
    |     ---------- ^^^^^^^^^^ `impl Future<Output = i32>` cannot be sent between threads safely
@@ -28,7 +28,7 @@ LL |     needs_send(T::test2());
    |
    = help: the trait `Send` is not implemented for `impl Future<Output = i32>`
 note: required by a bound in `needs_send`
-  --> $DIR/send-on-async-fn-in-trait.rs:13:27
+  --> $DIR/send-on-async-fn-in-trait.rs:12:27
    |
 LL |     fn needs_send(_: impl Send) {}
    |                           ^^^^ required by this bound in `needs_send`
diff --git a/tests/ui/async-await/in-trait/send-on-foreign-async-fn-in-trait.rs b/tests/ui/async-await/in-trait/send-on-foreign-async-fn-in-trait.rs
index 83b69d72a96..f0d750714cd 100644
--- a/tests/ui/async-await/in-trait/send-on-foreign-async-fn-in-trait.rs
+++ b/tests/ui/async-await/in-trait/send-on-foreign-async-fn-in-trait.rs
@@ -1,8 +1,6 @@
 // aux-build:foreign-async-fn.rs
 // edition:2021
 
-#![feature(async_fn_in_trait)]
-
 extern crate foreign_async_fn;
 use foreign_async_fn::Foo;
 
diff --git a/tests/ui/async-await/in-trait/send-on-foreign-async-fn-in-trait.stderr b/tests/ui/async-await/in-trait/send-on-foreign-async-fn-in-trait.stderr
index f337a04ba19..482707351d7 100644
--- a/tests/ui/async-await/in-trait/send-on-foreign-async-fn-in-trait.stderr
+++ b/tests/ui/async-await/in-trait/send-on-foreign-async-fn-in-trait.stderr
@@ -1,5 +1,5 @@
 error[E0277]: `impl Future<Output = ()>` cannot be sent between threads safely
-  --> $DIR/send-on-foreign-async-fn-in-trait.rs:11:16
+  --> $DIR/send-on-foreign-async-fn-in-trait.rs:9:16
    |
 LL |     needs_send(T::test());
    |     ---------- ^^^^^^^^^ `impl Future<Output = ()>` cannot be sent between threads safely
@@ -8,12 +8,12 @@ LL |     needs_send(T::test());
    |
    = help: the trait `Send` is not implemented for `impl Future<Output = ()>`
 note: `<T as Foo>::test` is an `async fn` in trait, which does not automatically imply that its future is `Send`
-  --> $DIR/auxiliary/foreign-async-fn.rs:6:5
+  --> $DIR/auxiliary/foreign-async-fn.rs:4:5
    |
 LL |     async fn test();
    |     ^^^^^^^^^^^^^^^^
 note: required by a bound in `needs_send`
-  --> $DIR/send-on-foreign-async-fn-in-trait.rs:10:27
+  --> $DIR/send-on-foreign-async-fn-in-trait.rs:8:27
    |
 LL |     fn needs_send(_: impl Send) {}
    |                           ^^^^ required by this bound in `needs_send`
diff --git a/tests/ui/async-await/in-trait/warn.rs b/tests/ui/async-await/in-trait/warn.rs
index 4f981c31f5c..71f3822dfb1 100644
--- a/tests/ui/async-await/in-trait/warn.rs
+++ b/tests/ui/async-await/in-trait/warn.rs
@@ -1,6 +1,5 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait)]
 #![deny(async_fn_in_trait)]
 
 pub trait Foo {
diff --git a/tests/ui/async-await/in-trait/warn.stderr b/tests/ui/async-await/in-trait/warn.stderr
index eac41a6e924..e3ec3883224 100644
--- a/tests/ui/async-await/in-trait/warn.stderr
+++ b/tests/ui/async-await/in-trait/warn.stderr
@@ -1,12 +1,12 @@
 error: use of `async fn` in public traits is discouraged as auto trait bounds cannot be specified
-  --> $DIR/warn.rs:7:5
+  --> $DIR/warn.rs:6:5
    |
 LL |     async fn not_send();
    |     ^^^^^
    |
    = note: you can suppress this lint if you plan to use the trait only in your own code, or do not care about auto traits like `Send` on the `Future`
 note: the lint level is defined here
-  --> $DIR/warn.rs:4:9
+  --> $DIR/warn.rs:3:9
    |
 LL | #![deny(async_fn_in_trait)]
    |         ^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/async-await/issues/issue-95307.rs b/tests/ui/async-await/issues/issue-95307.rs
index f7e48070ccd..35dce2c6217 100644
--- a/tests/ui/async-await/issues/issue-95307.rs
+++ b/tests/ui/async-await/issues/issue-95307.rs
@@ -5,8 +5,7 @@
 
 pub trait C {
     async fn new() -> [u8; _];
-    //~^ ERROR: functions in traits cannot be declared `async`
-    //~| ERROR: using `_` for array lengths is unstable
+    //~^ ERROR: using `_` for array lengths is unstable
     //~| ERROR: in expressions, `_` can only be used on the left-hand side of an assignment
 }
 
diff --git a/tests/ui/async-await/issues/issue-95307.stderr b/tests/ui/async-await/issues/issue-95307.stderr
index a497cebe3c3..fdc6d5de1a8 100644
--- a/tests/ui/async-await/issues/issue-95307.stderr
+++ b/tests/ui/async-await/issues/issue-95307.stderr
@@ -1,16 +1,3 @@
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/issue-95307.rs:7:5
-   |
-LL |     async fn new() -> [u8; _];
-   |     -----^^^^^^^^^^^^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
 error: in expressions, `_` can only be used on the left-hand side of an assignment
   --> $DIR/issue-95307.rs:7:28
    |
@@ -26,7 +13,6 @@ LL |     async fn new() -> [u8; _];
    = note: see issue #85077 <https://github.com/rust-lang/rust/issues/85077> for more information
    = help: add `#![feature(generic_arg_infer)]` to the crate attributes to enable
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0658, E0706.
-For more information about an error, try `rustc --explain E0658`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/async-await/return-type-notation/issue-110963-early.rs b/tests/ui/async-await/return-type-notation/issue-110963-early.rs
index 0ecbca5c13b..07f2130bab5 100644
--- a/tests/ui/async-await/return-type-notation/issue-110963-early.rs
+++ b/tests/ui/async-await/return-type-notation/issue-110963-early.rs
@@ -2,7 +2,6 @@
 // known-bug: #110963
 
 #![feature(return_type_notation)]
-#![feature(async_fn_in_trait)]
 
 trait HealthCheck {
     async fn check<'a: 'a>(&'a mut self) -> bool;
diff --git a/tests/ui/async-await/return-type-notation/issue-110963-early.stderr b/tests/ui/async-await/return-type-notation/issue-110963-early.stderr
index 98e3cbd0d7f..feae2698e8f 100644
--- a/tests/ui/async-await/return-type-notation/issue-110963-early.stderr
+++ b/tests/ui/async-await/return-type-notation/issue-110963-early.stderr
@@ -8,7 +8,7 @@ LL | #![feature(return_type_notation)]
    = note: `#[warn(incomplete_features)]` on by default
 
 error[E0308]: mismatched types
-  --> $DIR/issue-110963-early.rs:15:5
+  --> $DIR/issue-110963-early.rs:14:5
    |
 LL | /     spawn(async move {
 LL | |         let mut hc = hc;
@@ -21,13 +21,13 @@ LL | |     });
    = note: expected trait `Send`
               found trait `for<'a> Send`
 note: the lifetime requirement is introduced here
-  --> $DIR/issue-110963-early.rs:35:17
+  --> $DIR/issue-110963-early.rs:34:17
    |
 LL |     F: Future + Send + 'static,
    |                 ^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/issue-110963-early.rs:15:5
+  --> $DIR/issue-110963-early.rs:14:5
    |
 LL | /     spawn(async move {
 LL | |         let mut hc = hc;
@@ -40,7 +40,7 @@ LL | |     });
    = note: expected trait `Send`
               found trait `for<'a> Send`
 note: the lifetime requirement is introduced here
-  --> $DIR/issue-110963-early.rs:35:17
+  --> $DIR/issue-110963-early.rs:34:17
    |
 LL |     F: Future + Send + 'static,
    |                 ^^^^
diff --git a/tests/ui/async-await/return-type-notation/issue-110963-late.rs b/tests/ui/async-await/return-type-notation/issue-110963-late.rs
index 17b5d775d44..7533844fb43 100644
--- a/tests/ui/async-await/return-type-notation/issue-110963-late.rs
+++ b/tests/ui/async-await/return-type-notation/issue-110963-late.rs
@@ -3,7 +3,6 @@
 
 #![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete
-#![feature(async_fn_in_trait)]
 
 trait HealthCheck {
     async fn check(&mut self) -> bool;
diff --git a/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.current.stderr b/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.current.stderr
index 8f45902035e..6a47f1ab983 100644
--- a/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.current.stderr
+++ b/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.current.stderr
@@ -1,5 +1,5 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:8:12
+  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:7:12
    |
 LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL | #![feature(return_type_notation)]
    = note: `#[warn(incomplete_features)]` on by default
 
 error[E0277]: `impl Future<Output = ()> { <_ as Foo>::bar() }` cannot be sent between threads safely
-  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:23:11
+  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:22:11
    |
 LL |     build(Bar);
    |     ----- ^^^ `impl Future<Output = ()> { <_ as Foo>::bar() }` cannot be sent between threads safely
@@ -17,7 +17,7 @@ LL |     build(Bar);
    |
    = help: the trait `for<'a> Send` is not implemented for `impl Future<Output = ()> { <_ as Foo>::bar() }`
 note: this is a known limitation of the trait solver that will be lifted in the future
-  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:23:11
+  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:22:11
    |
 LL |     build(Bar);
    |     ------^^^-
@@ -25,7 +25,7 @@ LL |     build(Bar);
    |     |     the trait solver is unable to infer the generic types that should be inferred from this argument
    |     add turbofish arguments to this call to specify the types manually, even if it's redundant
 note: required by a bound in `build`
-  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:20:39
+  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:19:39
    |
 LL | fn build<T>(_: T) where T: Foo<bar(): Send> {}
    |                                       ^^^^ required by this bound in `build`
diff --git a/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.next.stderr b/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.next.stderr
index 6fab7178767..4837815fad4 100644
--- a/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.next.stderr
+++ b/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.next.stderr
@@ -1,5 +1,5 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:8:12
+  --> $DIR/normalizing-self-auto-trait-issue-109924.rs:7:12
    |
 LL | #![feature(return_type_notation)]
    |            ^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.rs b/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.rs
index b2cd9707db9..e581e5ffda7 100644
--- a/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.rs
+++ b/tests/ui/async-await/return-type-notation/normalizing-self-auto-trait-issue-109924.rs
@@ -4,7 +4,6 @@
 //[next] compile-flags: -Ztrait-solver=next
 // edition:2021
 
-#![feature(async_fn_in_trait)]
 #![feature(return_type_notation)]
 //[next]~^ WARN the feature `return_type_notation` is incomplete
 
diff --git a/tests/ui/async-await/return-type-notation/rtn-implied-in-supertrait.rs b/tests/ui/async-await/return-type-notation/rtn-implied-in-supertrait.rs
index e55104ee968..0ceb62d449a 100644
--- a/tests/ui/async-await/return-type-notation/rtn-implied-in-supertrait.rs
+++ b/tests/ui/async-await/return-type-notation/rtn-implied-in-supertrait.rs
@@ -1,7 +1,7 @@
 // edition:2021
 // check-pass
 
-#![feature(async_fn_in_trait, return_position_impl_trait_in_trait, return_type_notation)]
+#![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete
 
 use std::future::Future;
diff --git a/tests/ui/async-await/return-type-notation/rtn-implied-in-supertrait.stderr b/tests/ui/async-await/return-type-notation/rtn-implied-in-supertrait.stderr
index 8626648b523..4a52e807bff 100644
--- a/tests/ui/async-await/return-type-notation/rtn-implied-in-supertrait.stderr
+++ b/tests/ui/async-await/return-type-notation/rtn-implied-in-supertrait.stderr
@@ -1,8 +1,8 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/rtn-implied-in-supertrait.rs:4:68
+  --> $DIR/rtn-implied-in-supertrait.rs:4:12
    |
-LL | #![feature(async_fn_in_trait, return_position_impl_trait_in_trait, return_type_notation)]
-   |                                                                    ^^^^^^^^^^^^^^^^^^^^
+LL | #![feature(return_type_notation)]
+   |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
    = note: `#[warn(incomplete_features)]` on by default
diff --git a/tests/ui/async-await/return-type-notation/super-method-bound-ambig.rs b/tests/ui/async-await/return-type-notation/super-method-bound-ambig.rs
index 028e526b5f5..891b30638ee 100644
--- a/tests/ui/async-await/return-type-notation/super-method-bound-ambig.rs
+++ b/tests/ui/async-await/return-type-notation/super-method-bound-ambig.rs
@@ -1,6 +1,6 @@
 // edition:2021
 
-#![feature(async_fn_in_trait, return_type_notation)]
+#![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete
 
 trait Super1<'a> {
diff --git a/tests/ui/async-await/return-type-notation/super-method-bound-ambig.stderr b/tests/ui/async-await/return-type-notation/super-method-bound-ambig.stderr
index 5bc8dbde4bc..d9caab5875a 100644
--- a/tests/ui/async-await/return-type-notation/super-method-bound-ambig.stderr
+++ b/tests/ui/async-await/return-type-notation/super-method-bound-ambig.stderr
@@ -1,8 +1,8 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/super-method-bound-ambig.rs:3:31
+  --> $DIR/super-method-bound-ambig.rs:3:12
    |
-LL | #![feature(async_fn_in_trait, return_type_notation)]
-   |                               ^^^^^^^^^^^^^^^^^^^^
+LL | #![feature(return_type_notation)]
+   |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
    = note: `#[warn(incomplete_features)]` on by default
diff --git a/tests/ui/async-await/return-type-notation/super-method-bound.current.stderr b/tests/ui/async-await/return-type-notation/super-method-bound.current.stderr
index 891c802c5f4..5f482b60878 100644
--- a/tests/ui/async-await/return-type-notation/super-method-bound.current.stderr
+++ b/tests/ui/async-await/return-type-notation/super-method-bound.current.stderr
@@ -1,8 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/super-method-bound.rs:6:31
    |
-LL | #![feature(async_fn_in_trait, return_type_notation)]
-   |                               ^^^^^^^^^^^^^^^^^^^^
+LL | #![feature(return_type_notation)]   |                               ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
    = note: `#[warn(incomplete_features)]` on by default
diff --git a/tests/ui/async-await/return-type-notation/super-method-bound.next.stderr b/tests/ui/async-await/return-type-notation/super-method-bound.next.stderr
index 891c802c5f4..5f482b60878 100644
--- a/tests/ui/async-await/return-type-notation/super-method-bound.next.stderr
+++ b/tests/ui/async-await/return-type-notation/super-method-bound.next.stderr
@@ -1,8 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/super-method-bound.rs:6:31
    |
-LL | #![feature(async_fn_in_trait, return_type_notation)]
-   |                               ^^^^^^^^^^^^^^^^^^^^
+LL | #![feature(return_type_notation)]   |                               ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
    = note: `#[warn(incomplete_features)]` on by default
diff --git a/tests/ui/async-await/return-type-notation/super-method-bound.rs b/tests/ui/async-await/return-type-notation/super-method-bound.rs
index 58ea3578db6..6025cda2f5d 100644
--- a/tests/ui/async-await/return-type-notation/super-method-bound.rs
+++ b/tests/ui/async-await/return-type-notation/super-method-bound.rs
@@ -1,7 +1,7 @@
 // edition:2021
 // check-pass
 
-#![feature(async_fn_in_trait, return_type_notation)]
+#![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete
 
 trait Super<'a> {
diff --git a/tests/ui/async-await/return-type-notation/super-method-bound.stderr b/tests/ui/async-await/return-type-notation/super-method-bound.stderr
index ac0668d3c44..64fda71c1a1 100644
--- a/tests/ui/async-await/return-type-notation/super-method-bound.stderr
+++ b/tests/ui/async-await/return-type-notation/super-method-bound.stderr
@@ -1,8 +1,8 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/super-method-bound.rs:4:31
+  --> $DIR/super-method-bound.rs:4:12
    |
-LL | #![feature(async_fn_in_trait, return_type_notation)]
-   |                               ^^^^^^^^^^^^^^^^^^^^
+LL | #![feature(return_type_notation)]
+   |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
    = note: `#[warn(incomplete_features)]` on by default
diff --git a/tests/ui/async-await/return-type-notation/supertrait-bound.current.stderr b/tests/ui/async-await/return-type-notation/supertrait-bound.current.stderr
index 05cb0ca4abd..928b321697c 100644
--- a/tests/ui/async-await/return-type-notation/supertrait-bound.current.stderr
+++ b/tests/ui/async-await/return-type-notation/supertrait-bound.current.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/supertrait-bound.rs:5:49
    |
-LL | #![feature(return_position_impl_trait_in_trait, return_type_notation)]
+LL | #![feature(return_type_notation)]
    |                                                 ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/async-await/return-type-notation/supertrait-bound.next.stderr b/tests/ui/async-await/return-type-notation/supertrait-bound.next.stderr
index 05cb0ca4abd..928b321697c 100644
--- a/tests/ui/async-await/return-type-notation/supertrait-bound.next.stderr
+++ b/tests/ui/async-await/return-type-notation/supertrait-bound.next.stderr
@@ -1,7 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/supertrait-bound.rs:5:49
    |
-LL | #![feature(return_position_impl_trait_in_trait, return_type_notation)]
+LL | #![feature(return_type_notation)]
    |                                                 ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
diff --git a/tests/ui/async-await/return-type-notation/supertrait-bound.rs b/tests/ui/async-await/return-type-notation/supertrait-bound.rs
index 19bcfe3046b..a85596a9fee 100644
--- a/tests/ui/async-await/return-type-notation/supertrait-bound.rs
+++ b/tests/ui/async-await/return-type-notation/supertrait-bound.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait, return_type_notation)]
+#![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete and may not be safe to use
 
 trait IntFactory {
diff --git a/tests/ui/async-await/return-type-notation/supertrait-bound.stderr b/tests/ui/async-await/return-type-notation/supertrait-bound.stderr
index c8cec4946b4..eb6917fc7d5 100644
--- a/tests/ui/async-await/return-type-notation/supertrait-bound.stderr
+++ b/tests/ui/async-await/return-type-notation/supertrait-bound.stderr
@@ -1,8 +1,8 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/supertrait-bound.rs:3:49
+  --> $DIR/supertrait-bound.rs:3:12
    |
-LL | #![feature(return_position_impl_trait_in_trait, return_type_notation)]
-   |                                                 ^^^^^^^^^^^^^^^^^^^^
+LL | #![feature(return_type_notation)]
+   |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
    = note: `#[warn(incomplete_features)]` on by default
diff --git a/tests/ui/async-await/return-type-notation/ty-or-ct-params.current.stderr b/tests/ui/async-await/return-type-notation/ty-or-ct-params.current.stderr
index 1aa008fe469..e2bbb6013fc 100644
--- a/tests/ui/async-await/return-type-notation/ty-or-ct-params.current.stderr
+++ b/tests/ui/async-await/return-type-notation/ty-or-ct-params.current.stderr
@@ -1,8 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/ty-or-ct-params.rs:5:31
    |
-LL | #![feature(async_fn_in_trait, return_type_notation)]
-   |                               ^^^^^^^^^^^^^^^^^^^^
+LL | #![feature(return_type_notation)]   |                               ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
    = note: `#[warn(incomplete_features)]` on by default
diff --git a/tests/ui/async-await/return-type-notation/ty-or-ct-params.next.stderr b/tests/ui/async-await/return-type-notation/ty-or-ct-params.next.stderr
index 1aa008fe469..e2bbb6013fc 100644
--- a/tests/ui/async-await/return-type-notation/ty-or-ct-params.next.stderr
+++ b/tests/ui/async-await/return-type-notation/ty-or-ct-params.next.stderr
@@ -1,8 +1,7 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
   --> $DIR/ty-or-ct-params.rs:5:31
    |
-LL | #![feature(async_fn_in_trait, return_type_notation)]
-   |                               ^^^^^^^^^^^^^^^^^^^^
+LL | #![feature(return_type_notation)]   |                               ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
    = note: `#[warn(incomplete_features)]` on by default
diff --git a/tests/ui/async-await/return-type-notation/ty-or-ct-params.rs b/tests/ui/async-await/return-type-notation/ty-or-ct-params.rs
index 7871a2fed03..ac320cfc679 100644
--- a/tests/ui/async-await/return-type-notation/ty-or-ct-params.rs
+++ b/tests/ui/async-await/return-type-notation/ty-or-ct-params.rs
@@ -1,6 +1,6 @@
 // edition: 2021
 
-#![feature(async_fn_in_trait, return_type_notation)]
+#![feature(return_type_notation)]
 //~^ WARN the feature `return_type_notation` is incomplete
 
 trait Foo {
diff --git a/tests/ui/async-await/return-type-notation/ty-or-ct-params.stderr b/tests/ui/async-await/return-type-notation/ty-or-ct-params.stderr
index 76928c5d7a3..da94d9d1e6d 100644
--- a/tests/ui/async-await/return-type-notation/ty-or-ct-params.stderr
+++ b/tests/ui/async-await/return-type-notation/ty-or-ct-params.stderr
@@ -1,8 +1,8 @@
 warning: the feature `return_type_notation` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/ty-or-ct-params.rs:3:31
+  --> $DIR/ty-or-ct-params.rs:3:12
    |
-LL | #![feature(async_fn_in_trait, return_type_notation)]
-   |                               ^^^^^^^^^^^^^^^^^^^^
+LL | #![feature(return_type_notation)]
+   |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #109417 <https://github.com/rust-lang/rust/issues/109417> for more information
    = note: `#[warn(incomplete_features)]` on by default
diff --git a/tests/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.rs b/tests/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.rs
deleted file mode 100644
index a8d6365ca79..00000000000
--- a/tests/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.rs
+++ /dev/null
@@ -1,18 +0,0 @@
-// edition:2021
-
-// async_fn_in_trait is not enough to allow use of RPITIT
-#![allow(incomplete_features)]
-#![feature(async_fn_in_trait)]
-
-trait Foo {
-    fn bar() -> impl Sized; //~ ERROR `impl Trait` only allowed in function and inherent method argument and return types, not in trait method return
-    fn baz() -> Box<impl std::fmt::Display>; //~ ERROR `impl Trait` only allowed in function and inherent method argument and return types, not in trait method return
-}
-
-// Both return_position_impl_trait_in_trait and async_fn_in_trait are required for this (see also
-// feature-gate-async_fn_in_trait.rs)
-trait AsyncFoo {
-    async fn bar() -> impl Sized; //~ ERROR `impl Trait` only allowed in function and inherent method argument and return types, not in trait method return
-}
-
-fn main() {}
diff --git a/tests/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.stderr b/tests/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.stderr
deleted file mode 100644
index 86f138fabdb..00000000000
--- a/tests/ui/feature-gates/feature-gate-return_position_impl_trait_in_trait.stderr
+++ /dev/null
@@ -1,30 +0,0 @@
-error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in trait method return types
-  --> $DIR/feature-gate-return_position_impl_trait_in_trait.rs:8:17
-   |
-LL |     fn bar() -> impl Sized;
-   |                 ^^^^^^^^^^
-   |
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
-
-error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in trait method return types
-  --> $DIR/feature-gate-return_position_impl_trait_in_trait.rs:9:21
-   |
-LL |     fn baz() -> Box<impl std::fmt::Display>;
-   |                     ^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
-
-error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in trait method return types
-  --> $DIR/feature-gate-return_position_impl_trait_in_trait.rs:15:23
-   |
-LL |     async fn bar() -> impl Sized;
-   |                       ^^^^^^^^^^
-   |
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0562`.
diff --git a/tests/ui/feature-gates/feature-gate-return_type_notation.cfg.stderr b/tests/ui/feature-gates/feature-gate-return_type_notation.cfg.stderr
index f6230b76463..1bdb2574ead 100644
--- a/tests/ui/feature-gates/feature-gate-return_type_notation.cfg.stderr
+++ b/tests/ui/feature-gates/feature-gate-return_type_notation.cfg.stderr
@@ -1,5 +1,5 @@
 error[E0658]: return type notation is experimental
-  --> $DIR/feature-gate-return_type_notation.rs:15:17
+  --> $DIR/feature-gate-return_type_notation.rs:14:17
    |
 LL | fn foo<T: Trait<m(): Send>>() {}
    |                 ^^^^^^^^^
@@ -8,7 +8,7 @@ LL | fn foo<T: Trait<m(): Send>>() {}
    = help: add `#![feature(return_type_notation)]` to the crate attributes to enable
 
 error: parenthesized generic arguments cannot be used in associated type constraints
-  --> $DIR/feature-gate-return_type_notation.rs:15:17
+  --> $DIR/feature-gate-return_type_notation.rs:14:17
    |
 LL | fn foo<T: Trait<m(): Send>>() {}
    |                 ^--
@@ -16,7 +16,7 @@ LL | fn foo<T: Trait<m(): Send>>() {}
    |                  help: remove these parentheses
 
 error[E0220]: associated type `m` not found for `Trait`
-  --> $DIR/feature-gate-return_type_notation.rs:15:17
+  --> $DIR/feature-gate-return_type_notation.rs:14:17
    |
 LL | fn foo<T: Trait<m(): Send>>() {}
    |                 ^ associated type `m` not found
diff --git a/tests/ui/feature-gates/feature-gate-return_type_notation.no.stderr b/tests/ui/feature-gates/feature-gate-return_type_notation.no.stderr
index c7f52d7cddc..dd6ebb61038 100644
--- a/tests/ui/feature-gates/feature-gate-return_type_notation.no.stderr
+++ b/tests/ui/feature-gates/feature-gate-return_type_notation.no.stderr
@@ -1,5 +1,5 @@
 warning: return type notation is experimental
-  --> $DIR/feature-gate-return_type_notation.rs:15:17
+  --> $DIR/feature-gate-return_type_notation.rs:14:17
    |
 LL | fn foo<T: Trait<m(): Send>>() {}
    |                 ^^^^^^^^^
diff --git a/tests/ui/feature-gates/feature-gate-return_type_notation.rs b/tests/ui/feature-gates/feature-gate-return_type_notation.rs
index c0c285cef3c..86e2c48e188 100644
--- a/tests/ui/feature-gates/feature-gate-return_type_notation.rs
+++ b/tests/ui/feature-gates/feature-gate-return_type_notation.rs
@@ -4,7 +4,6 @@
 // [no] check-pass
 // Since we're not adding new syntax, `cfg`'d out RTN must pass.
 
-#![feature(async_fn_in_trait)]
 
 trait Trait {
     #[allow(async_fn_in_trait)]
diff --git a/tests/ui/impl-trait/in-trait/anonymize-binders-for-refine.rs b/tests/ui/impl-trait/in-trait/anonymize-binders-for-refine.rs
index e62662f2f07..09fbef2ec07 100644
--- a/tests/ui/impl-trait/in-trait/anonymize-binders-for-refine.rs
+++ b/tests/ui/impl-trait/in-trait/anonymize-binders-for-refine.rs
@@ -1,7 +1,6 @@
 // compile-flags: --crate-type=lib
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait)]
 #![deny(refining_impl_trait)]
 
 pub trait Tr<T> {
diff --git a/tests/ui/impl-trait/in-trait/assumed-wf-bounds-in-impl.rs b/tests/ui/impl-trait/in-trait/assumed-wf-bounds-in-impl.rs
index 5de9c01e3e0..afb9992de49 100644
--- a/tests/ui/impl-trait/in-trait/assumed-wf-bounds-in-impl.rs
+++ b/tests/ui/impl-trait/in-trait/assumed-wf-bounds-in-impl.rs
@@ -2,7 +2,6 @@
 // edition: 2021
 // issue: 113796
 
-#![feature(async_fn_in_trait)]
 
 trait AsyncLendingIterator {
     type Item<'a>
diff --git a/tests/ui/impl-trait/in-trait/auxiliary/rpitit.rs b/tests/ui/impl-trait/in-trait/auxiliary/rpitit.rs
index 6e99402113a..a213994ff86 100644
--- a/tests/ui/impl-trait/in-trait/auxiliary/rpitit.rs
+++ b/tests/ui/impl-trait/in-trait/auxiliary/rpitit.rs
@@ -1,4 +1,4 @@
-#![feature(return_position_impl_trait_in_trait, lint_reasons)]
+#![feature(lint_reasons)]
 
 use std::ops::Deref;
 
diff --git a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.rs b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.rs
index 3a93dfee57f..41d5f0f6449 100644
--- a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.rs
+++ b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.rs
@@ -1,6 +1,5 @@
 // issue: 114146
 
-#![feature(return_position_impl_trait_in_trait)]
 
 trait Foo {
     fn bar<'other: 'a>() -> impl Sized + 'a {}
diff --git a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.stderr b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.stderr
index 3a1f8f90837..b0832eb33ca 100644
--- a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.stderr
+++ b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.stderr
@@ -1,5 +1,5 @@
 error[E0261]: use of undeclared lifetime name `'a`
-  --> $DIR/bad-item-bound-within-rpitit-2.rs:6:20
+  --> $DIR/bad-item-bound-within-rpitit-2.rs:5:20
    |
 LL |     fn bar<'other: 'a>() -> impl Sized + 'a {}
    |                    ^^ undeclared lifetime
@@ -14,7 +14,7 @@ LL | trait Foo<'a> {
    |          ++++
 
 error[E0261]: use of undeclared lifetime name `'a`
-  --> $DIR/bad-item-bound-within-rpitit-2.rs:6:42
+  --> $DIR/bad-item-bound-within-rpitit-2.rs:5:42
    |
 LL |     fn bar<'other: 'a>() -> impl Sized + 'a {}
    |                                          ^^ undeclared lifetime
diff --git a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit.rs b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit.rs
index fbbbb8585d1..5ddc97f1adc 100644
--- a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit.rs
+++ b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit.rs
@@ -1,6 +1,5 @@
 // issue: 114145
 
-#![feature(return_position_impl_trait_in_trait)]
 
 pub trait Iterable {
     type Item<'a>
diff --git a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit.stderr b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit.stderr
index a5fb338ea4e..324eaa37a3d 100644
--- a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit.stderr
+++ b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit.stderr
@@ -1,5 +1,5 @@
 error[E0276]: impl has stricter requirements than trait
-  --> $DIR/bad-item-bound-within-rpitit.rs:16:13
+  --> $DIR/bad-item-bound-within-rpitit.rs:15:13
    |
 LL |     type Item<'a>
    |     ------------- definition of `Item` from trait
@@ -13,7 +13,7 @@ LL |     where Self: 'b;
    |     ~~~~~~~~~~~~~~
 
 warning: impl trait in impl method signature does not match trait method signature
-  --> $DIR/bad-item-bound-within-rpitit.rs:19:28
+  --> $DIR/bad-item-bound-within-rpitit.rs:18:28
    |
 LL |     fn iter(&self) -> impl '_ + Iterator<Item = Self::Item<'_>>;
    |                       ----------------------------------------- return type from trait method defined here
diff --git a/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.rs b/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.rs
index f5ee4690fa9..87eb7beb1ee 100644
--- a/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.rs
+++ b/tests/ui/impl-trait/in-trait/box-coerce-span-in-default.rs
@@ -1,6 +1,5 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait)]
 
 struct TestA {}
 struct TestB {}
diff --git a/tests/ui/impl-trait/in-trait/check-wf-on-non-defaulted-rpitit.rs b/tests/ui/impl-trait/in-trait/check-wf-on-non-defaulted-rpitit.rs
index 742537ffcc4..2845b401bd5 100644
--- a/tests/ui/impl-trait/in-trait/check-wf-on-non-defaulted-rpitit.rs
+++ b/tests/ui/impl-trait/in-trait/check-wf-on-non-defaulted-rpitit.rs
@@ -1,5 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
-
 struct Wrapper<G: Send>(G);
 
 trait Foo {
diff --git a/tests/ui/impl-trait/in-trait/check-wf-on-non-defaulted-rpitit.stderr b/tests/ui/impl-trait/in-trait/check-wf-on-non-defaulted-rpitit.stderr
index dee87d08238..1570b2ecd53 100644
--- a/tests/ui/impl-trait/in-trait/check-wf-on-non-defaulted-rpitit.stderr
+++ b/tests/ui/impl-trait/in-trait/check-wf-on-non-defaulted-rpitit.stderr
@@ -1,12 +1,12 @@
 error[E0277]: `impl Sized` cannot be sent between threads safely
-  --> $DIR/check-wf-on-non-defaulted-rpitit.rs:6:17
+  --> $DIR/check-wf-on-non-defaulted-rpitit.rs:4:17
    |
 LL |     fn bar() -> Wrapper<impl Sized>;
    |                 ^^^^^^^^^^^^^^^^^^^ `impl Sized` cannot be sent between threads safely
    |
    = help: the trait `Send` is not implemented for `impl Sized`
 note: required by a bound in `Wrapper`
-  --> $DIR/check-wf-on-non-defaulted-rpitit.rs:3:19
+  --> $DIR/check-wf-on-non-defaulted-rpitit.rs:1:19
    |
 LL | struct Wrapper<G: Send>(G);
    |                   ^^^^ required by this bound in `Wrapper`
diff --git a/tests/ui/impl-trait/in-trait/deep-match-works.rs b/tests/ui/impl-trait/in-trait/deep-match-works.rs
index fc290f11f9d..8c992743862 100644
--- a/tests/ui/impl-trait/in-trait/deep-match-works.rs
+++ b/tests/ui/impl-trait/in-trait/deep-match-works.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait, lint_reasons)]
+#![feature(lint_reasons)]
 #![allow(incomplete_features)]
 
 pub struct Wrapper<T>(T);
diff --git a/tests/ui/impl-trait/in-trait/deep-match.rs b/tests/ui/impl-trait/in-trait/deep-match.rs
index 0cae88f349f..02889347ba4 100644
--- a/tests/ui/impl-trait/in-trait/deep-match.rs
+++ b/tests/ui/impl-trait/in-trait/deep-match.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 struct Wrapper<T>(T);
diff --git a/tests/ui/impl-trait/in-trait/deep-match.stderr b/tests/ui/impl-trait/in-trait/deep-match.stderr
index f0ad3c16e9c..9cfc54f5094 100644
--- a/tests/ui/impl-trait/in-trait/deep-match.stderr
+++ b/tests/ui/impl-trait/in-trait/deep-match.stderr
@@ -1,5 +1,5 @@
 error[E0053]: method `bar` has an incompatible return type for trait
-  --> $DIR/deep-match.rs:11:17
+  --> $DIR/deep-match.rs:10:17
    |
 LL |     fn bar() -> i32 {
    |                 ^^^
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err-2.rs b/tests/ui/impl-trait/in-trait/default-body-type-err-2.rs
index 45ae2b8ad3a..29bcbe16d83 100644
--- a/tests/ui/impl-trait/in-trait/default-body-type-err-2.rs
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err-2.rs
@@ -1,7 +1,6 @@
 // edition:2021
 
 #![allow(incomplete_features)]
-#![feature(async_fn_in_trait)]
 
 pub trait Foo {
     async fn woopsie_async(&self) -> String {
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err-2.stderr b/tests/ui/impl-trait/in-trait/default-body-type-err-2.stderr
index cc3bdf0e571..fcace10cd01 100644
--- a/tests/ui/impl-trait/in-trait/default-body-type-err-2.stderr
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err-2.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/default-body-type-err-2.rs:8:9
+  --> $DIR/default-body-type-err-2.rs:7:9
    |
 LL |         42
    |         ^^- help: try using a conversion method: `.to_string()`
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err.rs b/tests/ui/impl-trait/in-trait/default-body-type-err.rs
index ac9baf91cae..977ff8111dd 100644
--- a/tests/ui/impl-trait/in-trait/default-body-type-err.rs
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err.rs
@@ -1,5 +1,4 @@
 #![allow(incomplete_features)]
-#![feature(return_position_impl_trait_in_trait)]
 
 use std::ops::Deref;
 
diff --git a/tests/ui/impl-trait/in-trait/default-body-type-err.stderr b/tests/ui/impl-trait/in-trait/default-body-type-err.stderr
index 4742eb37d3e..3d9ca62b0db 100644
--- a/tests/ui/impl-trait/in-trait/default-body-type-err.stderr
+++ b/tests/ui/impl-trait/in-trait/default-body-type-err.stderr
@@ -1,5 +1,5 @@
 error[E0271]: type mismatch resolving `<&i32 as Deref>::Target == String`
-  --> $DIR/default-body-type-err.rs:7:22
+  --> $DIR/default-body-type-err.rs:6:22
    |
 LL |     fn lol(&self) -> impl Deref<Target = String> {
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `i32`, found `String`
diff --git a/tests/ui/impl-trait/in-trait/default-body-with-rpit.rs b/tests/ui/impl-trait/in-trait/default-body-with-rpit.rs
index 9c60cf4e72a..1d1f555080c 100644
--- a/tests/ui/impl-trait/in-trait/default-body-with-rpit.rs
+++ b/tests/ui/impl-trait/in-trait/default-body-with-rpit.rs
@@ -1,7 +1,6 @@
 // edition:2021
 // check-pass
 
-#![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Debug;
diff --git a/tests/ui/impl-trait/in-trait/default-body.rs b/tests/ui/impl-trait/in-trait/default-body.rs
index d3ea9fbeabc..ff70f1e232d 100644
--- a/tests/ui/impl-trait/in-trait/default-body.rs
+++ b/tests/ui/impl-trait/in-trait/default-body.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition:2021
 
-#![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Debug;
diff --git a/tests/ui/impl-trait/in-trait/default-method-binder-shifting.rs b/tests/ui/impl-trait/in-trait/default-method-binder-shifting.rs
index 817a4d7dbbe..ca41eb8bc71 100644
--- a/tests/ui/impl-trait/in-trait/default-method-binder-shifting.rs
+++ b/tests/ui/impl-trait/in-trait/default-method-binder-shifting.rs
@@ -1,6 +1,5 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait)]
 
 trait Trait {
     type Type;
diff --git a/tests/ui/impl-trait/in-trait/default-method-constraint.rs b/tests/ui/impl-trait/in-trait/default-method-constraint.rs
index 28d76241f27..8ab2e2797f1 100644
--- a/tests/ui/impl-trait/in-trait/default-method-constraint.rs
+++ b/tests/ui/impl-trait/in-trait/default-method-constraint.rs
@@ -2,7 +2,6 @@
 
 // This didn't work in the previous default RPITIT method hack attempt
 
-#![feature(return_position_impl_trait_in_trait)]
 
 trait Foo {
     fn bar(x: bool) -> impl Sized {
diff --git a/tests/ui/impl-trait/in-trait/doesnt-satisfy.rs b/tests/ui/impl-trait/in-trait/doesnt-satisfy.rs
index bb4e0d44f3e..5a53c9a19b5 100644
--- a/tests/ui/impl-trait/in-trait/doesnt-satisfy.rs
+++ b/tests/ui/impl-trait/in-trait/doesnt-satisfy.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 trait Foo {
diff --git a/tests/ui/impl-trait/in-trait/doesnt-satisfy.stderr b/tests/ui/impl-trait/in-trait/doesnt-satisfy.stderr
index 7c56ffa10e1..cb9ecc7fa48 100644
--- a/tests/ui/impl-trait/in-trait/doesnt-satisfy.stderr
+++ b/tests/ui/impl-trait/in-trait/doesnt-satisfy.stderr
@@ -1,5 +1,5 @@
 error[E0277]: `()` doesn't implement `std::fmt::Display`
-  --> $DIR/doesnt-satisfy.rs:9:17
+  --> $DIR/doesnt-satisfy.rs:8:17
    |
 LL |     fn bar() -> () {}
    |                 ^^ `()` cannot be formatted with the default formatter
@@ -7,7 +7,7 @@ LL |     fn bar() -> () {}
    = help: the trait `std::fmt::Display` is not implemented for `()`
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
 note: required by a bound in `Foo::{opaque#0}`
-  --> $DIR/doesnt-satisfy.rs:5:22
+  --> $DIR/doesnt-satisfy.rs:4:22
    |
 LL |     fn bar() -> impl std::fmt::Display;
    |                      ^^^^^^^^^^^^^^^^^ required by this bound in `Foo::{opaque#0}`
diff --git a/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.rs b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.rs
index 4719d5d3c67..fe0f011b6b0 100644
--- a/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.rs
+++ b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.rs
@@ -1,5 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
-
 trait MyTrait {
     fn foo(&self) -> impl Sized;
     fn bar(&self) -> impl Sized;
diff --git a/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.stderr b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.stderr
index 66ee142ccc4..830e663da37 100644
--- a/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.stderr
+++ b/tests/ui/impl-trait/in-trait/dont-project-to-rpitit-with-no-value.stderr
@@ -1,5 +1,5 @@
 error[E0046]: not all trait items implemented, missing: `foo`
-  --> $DIR/dont-project-to-rpitit-with-no-value.rs:8:1
+  --> $DIR/dont-project-to-rpitit-with-no-value.rs:6:1
    |
 LL |     fn foo(&self) -> impl Sized;
    |     ---------------------------- `foo` from trait
diff --git a/tests/ui/impl-trait/in-trait/early.rs b/tests/ui/impl-trait/in-trait/early.rs
index bb5718b4934..c4996674dd1 100644
--- a/tests/ui/impl-trait/in-trait/early.rs
+++ b/tests/ui/impl-trait/in-trait/early.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition:2021
 
-#![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 pub trait Foo {
diff --git a/tests/ui/impl-trait/in-trait/encode.rs b/tests/ui/impl-trait/in-trait/encode.rs
index efb9f6498ba..4df26b0f297 100644
--- a/tests/ui/impl-trait/in-trait/encode.rs
+++ b/tests/ui/impl-trait/in-trait/encode.rs
@@ -1,7 +1,6 @@
 // build-pass
 // compile-flags: --crate-type=lib
 
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 trait Foo {
diff --git a/tests/ui/impl-trait/in-trait/generics-mismatch.rs b/tests/ui/impl-trait/in-trait/generics-mismatch.rs
index cc0fc720ebb..2e5373dbd5d 100644
--- a/tests/ui/impl-trait/in-trait/generics-mismatch.rs
+++ b/tests/ui/impl-trait/in-trait/generics-mismatch.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 struct U;
diff --git a/tests/ui/impl-trait/in-trait/generics-mismatch.stderr b/tests/ui/impl-trait/in-trait/generics-mismatch.stderr
index cd42683e022..3dbf2235c5e 100644
--- a/tests/ui/impl-trait/in-trait/generics-mismatch.stderr
+++ b/tests/ui/impl-trait/in-trait/generics-mismatch.stderr
@@ -1,5 +1,5 @@
 error[E0049]: method `bar` has 1 type parameter but its trait declaration has 0 type parameters
-  --> $DIR/generics-mismatch.rs:11:12
+  --> $DIR/generics-mismatch.rs:10:12
    |
 LL |     fn bar(&self) -> impl Sized;
    |           - expected 0 type parameters
diff --git a/tests/ui/impl-trait/in-trait/issue-102140.rs b/tests/ui/impl-trait/in-trait/issue-102140.rs
index be1e012acb1..1132bd25f81 100644
--- a/tests/ui/impl-trait/in-trait/issue-102140.rs
+++ b/tests/ui/impl-trait/in-trait/issue-102140.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 trait Marker {}
diff --git a/tests/ui/impl-trait/in-trait/issue-102140.stderr b/tests/ui/impl-trait/in-trait/issue-102140.stderr
index 18bb63745d7..6d50d2f3a24 100644
--- a/tests/ui/impl-trait/in-trait/issue-102140.stderr
+++ b/tests/ui/impl-trait/in-trait/issue-102140.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
-  --> $DIR/issue-102140.rs:23:22
+  --> $DIR/issue-102140.rs:22:22
    |
 LL |         MyTrait::foo(&self)
    |         ------------ ^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
@@ -13,7 +13,7 @@ LL +         MyTrait::foo(self)
    |
 
 error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
-  --> $DIR/issue-102140.rs:23:9
+  --> $DIR/issue-102140.rs:22:9
    |
 LL |         MyTrait::foo(&self)
    |         ^^^^^^^^^^^^^^^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
@@ -21,7 +21,7 @@ LL |         MyTrait::foo(&self)
    = help: the trait `MyTrait` is implemented for `Outer`
 
 error[E0277]: the trait bound `&dyn MyTrait: MyTrait` is not satisfied
-  --> $DIR/issue-102140.rs:23:9
+  --> $DIR/issue-102140.rs:22:9
    |
 LL |         MyTrait::foo(&self)
    |         ^^^^^^^^^^^^ the trait `MyTrait` is not implemented for `&dyn MyTrait`
diff --git a/tests/ui/impl-trait/in-trait/issue-102301.rs b/tests/ui/impl-trait/in-trait/issue-102301.rs
index a93714a658e..600a21b07be 100644
--- a/tests/ui/impl-trait/in-trait/issue-102301.rs
+++ b/tests/ui/impl-trait/in-trait/issue-102301.rs
@@ -1,6 +1,5 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 trait Foo<T> {
diff --git a/tests/ui/impl-trait/in-trait/issue-102571.rs b/tests/ui/impl-trait/in-trait/issue-102571.rs
index ccb53031c44..4534753f0d2 100644
--- a/tests/ui/impl-trait/in-trait/issue-102571.rs
+++ b/tests/ui/impl-trait/in-trait/issue-102571.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Display;
diff --git a/tests/ui/impl-trait/in-trait/issue-102571.stderr b/tests/ui/impl-trait/in-trait/issue-102571.stderr
index 594b9ae9cd6..4d1a0feb22b 100644
--- a/tests/ui/impl-trait/in-trait/issue-102571.stderr
+++ b/tests/ui/impl-trait/in-trait/issue-102571.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-102571.rs:12:9
+  --> $DIR/issue-102571.rs:11:9
    |
 LL |     let () = t.bar();
    |         ^^   ------- this expression has type `impl Deref<Target = impl std::fmt::Display + ?Sized>`
diff --git a/tests/ui/impl-trait/in-trait/lifetime-in-associated-trait-bound.rs b/tests/ui/impl-trait/in-trait/lifetime-in-associated-trait-bound.rs
index 49d36d6c99c..4073ef8ac19 100644
--- a/tests/ui/impl-trait/in-trait/lifetime-in-associated-trait-bound.rs
+++ b/tests/ui/impl-trait/in-trait/lifetime-in-associated-trait-bound.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(associated_type_bounds, return_position_impl_trait_in_trait)]
+#![feature(associated_type_bounds)]
 
 trait Trait {
     type Type;
diff --git a/tests/ui/impl-trait/in-trait/method-signature-matches.lt.stderr b/tests/ui/impl-trait/in-trait/method-signature-matches.lt.stderr
index 239c4b35c72..59139e4d5ae 100644
--- a/tests/ui/impl-trait/in-trait/method-signature-matches.lt.stderr
+++ b/tests/ui/impl-trait/in-trait/method-signature-matches.lt.stderr
@@ -1,5 +1,5 @@
 error[E0053]: method `early` has an incompatible type for trait
-  --> $DIR/method-signature-matches.rs:58:27
+  --> $DIR/method-signature-matches.rs:57:27
    |
 LL |     fn early<'late, T>(_: &'late ()) {}
    |                     -     ^^^^^^^^^
@@ -9,7 +9,7 @@ LL |     fn early<'late, T>(_: &'late ()) {}
    |                     this type parameter
    |
 note: type in trait
-  --> $DIR/method-signature-matches.rs:53:28
+  --> $DIR/method-signature-matches.rs:52:28
    |
 LL |     fn early<'early, T>(x: &'early T) -> impl Sized;
    |                            ^^^^^^^^^
diff --git a/tests/ui/impl-trait/in-trait/method-signature-matches.mismatch.stderr b/tests/ui/impl-trait/in-trait/method-signature-matches.mismatch.stderr
index d3183b92e84..e0bd1cc4f19 100644
--- a/tests/ui/impl-trait/in-trait/method-signature-matches.mismatch.stderr
+++ b/tests/ui/impl-trait/in-trait/method-signature-matches.mismatch.stderr
@@ -1,5 +1,5 @@
 error[E0053]: method `owo` has an incompatible type for trait
-  --> $DIR/method-signature-matches.rs:14:15
+  --> $DIR/method-signature-matches.rs:13:15
    |
 LL |     fn owo(_: u8) {}
    |               ^^
@@ -8,7 +8,7 @@ LL |     fn owo(_: u8) {}
    |               help: change the parameter type to match the trait: `()`
    |
 note: type in trait
-  --> $DIR/method-signature-matches.rs:9:15
+  --> $DIR/method-signature-matches.rs:8:15
    |
 LL |     fn owo(x: ()) -> impl Sized;
    |               ^^
diff --git a/tests/ui/impl-trait/in-trait/method-signature-matches.mismatch_async.stderr b/tests/ui/impl-trait/in-trait/method-signature-matches.mismatch_async.stderr
index 80fda1c9fe1..096e96c85c4 100644
--- a/tests/ui/impl-trait/in-trait/method-signature-matches.mismatch_async.stderr
+++ b/tests/ui/impl-trait/in-trait/method-signature-matches.mismatch_async.stderr
@@ -1,5 +1,5 @@
 error[E0053]: method `owo` has an incompatible type for trait
-  --> $DIR/method-signature-matches.rs:25:21
+  --> $DIR/method-signature-matches.rs:24:21
    |
 LL |     async fn owo(_: u8) {}
    |                     ^^
@@ -8,7 +8,7 @@ LL |     async fn owo(_: u8) {}
    |                     help: change the parameter type to match the trait: `()`
    |
 note: type in trait
-  --> $DIR/method-signature-matches.rs:20:21
+  --> $DIR/method-signature-matches.rs:19:21
    |
 LL |     async fn owo(x: ()) {}
    |                     ^^
diff --git a/tests/ui/impl-trait/in-trait/method-signature-matches.rs b/tests/ui/impl-trait/in-trait/method-signature-matches.rs
index 294f93b30d0..99ace66facb 100644
--- a/tests/ui/impl-trait/in-trait/method-signature-matches.rs
+++ b/tests/ui/impl-trait/in-trait/method-signature-matches.rs
@@ -1,7 +1,6 @@
 // edition: 2021
 // revisions: mismatch mismatch_async too_many too_few lt
 
-#![feature(return_position_impl_trait_in_trait, async_fn_in_trait)]
 #![allow(incomplete_features)]
 
 #[cfg(mismatch)]
diff --git a/tests/ui/impl-trait/in-trait/method-signature-matches.too_few.stderr b/tests/ui/impl-trait/in-trait/method-signature-matches.too_few.stderr
index 24bcfeb748f..96eff1a5815 100644
--- a/tests/ui/impl-trait/in-trait/method-signature-matches.too_few.stderr
+++ b/tests/ui/impl-trait/in-trait/method-signature-matches.too_few.stderr
@@ -1,5 +1,5 @@
 error[E0050]: method `come_on_a_little_more_effort` has 0 parameters but the declaration in trait `TooLittle::come_on_a_little_more_effort` has 3
-  --> $DIR/method-signature-matches.rs:47:5
+  --> $DIR/method-signature-matches.rs:46:5
    |
 LL |     fn come_on_a_little_more_effort(_: (), _: (), _: ()) -> impl Sized;
    |                                        ---------------- trait requires 3 parameters
diff --git a/tests/ui/impl-trait/in-trait/method-signature-matches.too_many.stderr b/tests/ui/impl-trait/in-trait/method-signature-matches.too_many.stderr
index 616cbd2905c..0fc847051c9 100644
--- a/tests/ui/impl-trait/in-trait/method-signature-matches.too_many.stderr
+++ b/tests/ui/impl-trait/in-trait/method-signature-matches.too_many.stderr
@@ -1,5 +1,5 @@
 error[E0050]: method `calm_down_please` has 3 parameters but the declaration in trait `TooMuch::calm_down_please` has 0
-  --> $DIR/method-signature-matches.rs:36:28
+  --> $DIR/method-signature-matches.rs:35:28
    |
 LL |     fn calm_down_please() -> impl Sized;
    |     ------------------------------------ trait requires 0 parameters
diff --git a/tests/ui/impl-trait/in-trait/missing-lt-outlives-in-rpitit-114274.rs b/tests/ui/impl-trait/in-trait/missing-lt-outlives-in-rpitit-114274.rs
index abc845d3afa..6088dcc61d6 100644
--- a/tests/ui/impl-trait/in-trait/missing-lt-outlives-in-rpitit-114274.rs
+++ b/tests/ui/impl-trait/in-trait/missing-lt-outlives-in-rpitit-114274.rs
@@ -1,5 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
-
 trait Iterable {
     type Item<'a>
     where
diff --git a/tests/ui/impl-trait/in-trait/missing-lt-outlives-in-rpitit-114274.stderr b/tests/ui/impl-trait/in-trait/missing-lt-outlives-in-rpitit-114274.stderr
index 0d74c0b69ce..1fd678a1f3a 100644
--- a/tests/ui/impl-trait/in-trait/missing-lt-outlives-in-rpitit-114274.stderr
+++ b/tests/ui/impl-trait/in-trait/missing-lt-outlives-in-rpitit-114274.stderr
@@ -1,5 +1,5 @@
 error[E0261]: use of undeclared lifetime name `'missing`
-  --> $DIR/missing-lt-outlives-in-rpitit-114274.rs:8:55
+  --> $DIR/missing-lt-outlives-in-rpitit-114274.rs:6:55
    |
 LL |     fn iter(&self) -> impl Iterator<Item = Self::Item<'missing>>;
    |                                                       ^^^^^^^^ undeclared lifetime
diff --git a/tests/ui/impl-trait/in-trait/nested-rpitit.rs b/tests/ui/impl-trait/in-trait/nested-rpitit.rs
index 58ba1acaf14..58b79c99155 100644
--- a/tests/ui/impl-trait/in-trait/nested-rpitit.rs
+++ b/tests/ui/impl-trait/in-trait/nested-rpitit.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait, lint_reasons)]
+#![feature(lint_reasons)]
 #![allow(incomplete_features)]
 
 use std::fmt::Display;
diff --git a/tests/ui/impl-trait/in-trait/object-safety-sized.rs b/tests/ui/impl-trait/in-trait/object-safety-sized.rs
index f221cfbb176..35afe80c97f 100644
--- a/tests/ui/impl-trait/in-trait/object-safety-sized.rs
+++ b/tests/ui/impl-trait/in-trait/object-safety-sized.rs
@@ -2,7 +2,6 @@
 // revisions: current next
 //[next] compile-flags: -Ztrait-solver=next
 
-#![feature(return_position_impl_trait_in_trait)]
 
 fn main() {
     let vec: Vec<Box<dyn Trait>> = Vec::new();
diff --git a/tests/ui/impl-trait/in-trait/object-safety.rs b/tests/ui/impl-trait/in-trait/object-safety.rs
index d1c9fba4e99..15634537dae 100644
--- a/tests/ui/impl-trait/in-trait/object-safety.rs
+++ b/tests/ui/impl-trait/in-trait/object-safety.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Debug;
diff --git a/tests/ui/impl-trait/in-trait/object-safety.stderr b/tests/ui/impl-trait/in-trait/object-safety.stderr
index 0170dc5d0fc..8d882391251 100644
--- a/tests/ui/impl-trait/in-trait/object-safety.stderr
+++ b/tests/ui/impl-trait/in-trait/object-safety.stderr
@@ -1,11 +1,11 @@
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety.rs:17:33
+  --> $DIR/object-safety.rs:16:33
    |
 LL |     let i = Box::new(42_u32) as Box<dyn Foo>;
    |                                 ^^^^^^^^^^^^ `Foo` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/object-safety.rs:7:22
+  --> $DIR/object-safety.rs:6:22
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
@@ -14,13 +14,13 @@ LL |     fn baz(&self) -> impl Debug;
    = help: consider moving `baz` to another trait
 
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety.rs:20:15
+  --> $DIR/object-safety.rs:19:15
    |
 LL |     let s = i.baz();
    |               ^^^ `Foo` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/object-safety.rs:7:22
+  --> $DIR/object-safety.rs:6:22
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
@@ -29,13 +29,13 @@ LL |     fn baz(&self) -> impl Debug;
    = help: consider moving `baz` to another trait
 
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety.rs:20:13
+  --> $DIR/object-safety.rs:19:13
    |
 LL |     let s = i.baz();
    |             ^^^^^^^ `Foo` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/object-safety.rs:7:22
+  --> $DIR/object-safety.rs:6:22
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
@@ -44,13 +44,13 @@ LL |     fn baz(&self) -> impl Debug;
    = help: consider moving `baz` to another trait
 
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety.rs:17:13
+  --> $DIR/object-safety.rs:16:13
    |
 LL |     let i = Box::new(42_u32) as Box<dyn Foo>;
    |             ^^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/object-safety.rs:7:22
+  --> $DIR/object-safety.rs:6:22
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
diff --git a/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs
index 3ac264e8eba..fc708536b0f 100644
--- a/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs
+++ b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Display;
diff --git a/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.stderr b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.stderr
index 15edda48340..99b62e80acd 100644
--- a/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.stderr
+++ b/tests/ui/impl-trait/in-trait/opaque-in-impl-is-opaque.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/opaque-in-impl-is-opaque.rs:17:19
+  --> $DIR/opaque-in-impl-is-opaque.rs:16:19
    |
 LL |     fn bar(&self) -> impl Display {
    |                      ------------ the found opaque type
diff --git a/tests/ui/impl-trait/in-trait/opaque-in-impl.rs b/tests/ui/impl-trait/in-trait/opaque-in-impl.rs
index 2e06629699a..3edd588a1b3 100644
--- a/tests/ui/impl-trait/in-trait/opaque-in-impl.rs
+++ b/tests/ui/impl-trait/in-trait/opaque-in-impl.rs
@@ -1,6 +1,5 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Debug;
diff --git a/tests/ui/impl-trait/in-trait/outlives-in-nested-rpit.rs b/tests/ui/impl-trait/in-trait/outlives-in-nested-rpit.rs
index 6330242ceeb..317ff7fe853 100644
--- a/tests/ui/impl-trait/in-trait/outlives-in-nested-rpit.rs
+++ b/tests/ui/impl-trait/in-trait/outlives-in-nested-rpit.rs
@@ -1,6 +1,5 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait)]
 
 trait Foo {
     fn early<'a, T: 'a>(x: &'a T) -> impl Iterator<Item = impl Into<&'a T>>;
diff --git a/tests/ui/impl-trait/in-trait/refine.rs b/tests/ui/impl-trait/in-trait/refine.rs
index f00478b0bb9..100e6da06a8 100644
--- a/tests/ui/impl-trait/in-trait/refine.rs
+++ b/tests/ui/impl-trait/in-trait/refine.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait, async_fn_in_trait)]
 #![deny(refining_impl_trait)]
 
 pub trait Foo {
diff --git a/tests/ui/impl-trait/in-trait/refine.stderr b/tests/ui/impl-trait/in-trait/refine.stderr
index 1d9852c682c..96a9bc059c8 100644
--- a/tests/ui/impl-trait/in-trait/refine.stderr
+++ b/tests/ui/impl-trait/in-trait/refine.stderr
@@ -1,5 +1,5 @@
 error: impl trait in impl method signature does not match trait method signature
-  --> $DIR/refine.rs:10:22
+  --> $DIR/refine.rs:9:22
    |
 LL |     fn bar() -> impl Sized;
    |                 ---------- return type from trait method defined here
@@ -9,7 +9,7 @@ LL |     fn bar() -> impl Copy {}
    |
    = note: add `#[allow(refining_impl_trait)]` if it is intended for this to be part of the public API of this crate
 note: the lint level is defined here
-  --> $DIR/refine.rs:2:9
+  --> $DIR/refine.rs:1:9
    |
 LL | #![deny(refining_impl_trait)]
    |         ^^^^^^^^^^^^^^^^^^^
@@ -19,7 +19,7 @@ LL |     fn bar() -> impl Sized {}
    |                 ~~~~~~~~~~
 
 error: impl trait in impl method signature does not match trait method signature
-  --> $DIR/refine.rs:16:5
+  --> $DIR/refine.rs:15:5
    |
 LL |     fn bar() -> impl Sized;
    |                 ---------- return type from trait method defined here
@@ -34,7 +34,7 @@ LL |     fn bar()-> impl Sized  {}
    |             +++++++++++++
 
 error: impl trait in impl method signature does not match trait method signature
-  --> $DIR/refine.rs:22:17
+  --> $DIR/refine.rs:21:17
    |
 LL |     fn bar() -> impl Sized;
    |                 ---------- return type from trait method defined here
@@ -49,7 +49,7 @@ LL |     fn bar() -> impl Sized {}
    |                 ~~~~~~~~~~
 
 error: impl trait in impl method signature does not match trait method signature
-  --> $DIR/refine.rs:44:27
+  --> $DIR/refine.rs:43:27
    |
 LL |     fn bar<'a>(&'a self) -> impl Sized + 'a;
    |                             --------------- return type from trait method defined here
diff --git a/tests/ui/impl-trait/in-trait/return-dont-satisfy-bounds.rs b/tests/ui/impl-trait/in-trait/return-dont-satisfy-bounds.rs
index 5d9a224ccd6..ad73b12feb5 100644
--- a/tests/ui/impl-trait/in-trait/return-dont-satisfy-bounds.rs
+++ b/tests/ui/impl-trait/in-trait/return-dont-satisfy-bounds.rs
@@ -1,5 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
-
 trait Foo<T> {
     fn foo<F2>(self) -> impl Foo<T>;
 }
diff --git a/tests/ui/impl-trait/in-trait/return-dont-satisfy-bounds.stderr b/tests/ui/impl-trait/in-trait/return-dont-satisfy-bounds.stderr
index 668fc6cbe7f..181d6a284da 100644
--- a/tests/ui/impl-trait/in-trait/return-dont-satisfy-bounds.stderr
+++ b/tests/ui/impl-trait/in-trait/return-dont-satisfy-bounds.stderr
@@ -1,12 +1,12 @@
 error[E0277]: the trait bound `impl Foo<u8>: Foo<char>` is not satisfied
-  --> $DIR/return-dont-satisfy-bounds.rs:10:34
+  --> $DIR/return-dont-satisfy-bounds.rs:8:34
    |
 LL |     fn foo<F2: Foo<u8>>(self) -> impl Foo<u8> {
    |                                  ^^^^^^^^^^^^ the trait `Foo<char>` is not implemented for `impl Foo<u8>`
    |
    = help: the trait `Foo<char>` is implemented for `Bar`
 note: required by a bound in `Foo::{opaque#0}`
-  --> $DIR/return-dont-satisfy-bounds.rs:4:30
+  --> $DIR/return-dont-satisfy-bounds.rs:2:30
    |
 LL |     fn foo<F2>(self) -> impl Foo<T>;
    |                              ^^^^^^ required by this bound in `Foo::{opaque#0}`
diff --git a/tests/ui/impl-trait/in-trait/reveal.rs b/tests/ui/impl-trait/in-trait/reveal.rs
index b1b46d75b8f..cc78ce8fea2 100644
--- a/tests/ui/impl-trait/in-trait/reveal.rs
+++ b/tests/ui/impl-trait/in-trait/reveal.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait, lint_reasons)]
+#![feature(lint_reasons)]
 #![allow(incomplete_features)]
 
 pub trait Foo {
diff --git a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf-via-param.rs b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf-via-param.rs
index 5e14a7f8e72..37b0b229776 100644
--- a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf-via-param.rs
+++ b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf-via-param.rs
@@ -1,5 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
-
 trait Extend {
     fn extend<'a: 'a>(_: &'a str) -> (impl Sized + 'a, &'static str);
 }
diff --git a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf-via-param.stderr b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf-via-param.stderr
index 1d947310e12..afc59cc5b58 100644
--- a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf-via-param.stderr
+++ b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf-via-param.stderr
@@ -1,12 +1,12 @@
 error[E0491]: in type `&'static &'a ()`, reference has a longer lifetime than the data it references
-  --> $DIR/rpitit-hidden-types-self-implied-wf-via-param.rs:8:38
+  --> $DIR/rpitit-hidden-types-self-implied-wf-via-param.rs:6:38
    |
 LL |     fn extend<'a: 'a>(s: &'a str) -> (Option<&'static &'a ()>, &'static str)
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the pointer is valid for the static lifetime
 note: but the referenced data is only valid for the lifetime `'a` as defined here
-  --> $DIR/rpitit-hidden-types-self-implied-wf-via-param.rs:8:15
+  --> $DIR/rpitit-hidden-types-self-implied-wf-via-param.rs:6:15
    |
 LL |     fn extend<'a: 'a>(s: &'a str) -> (Option<&'static &'a ()>, &'static str)
    |               ^^
diff --git a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.rs b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.rs
index c1885af4e5e..bacd5007768 100644
--- a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.rs
+++ b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.rs
@@ -1,5 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
-
 trait Extend {
     fn extend(_: &str) -> (impl Sized + '_, &'static str);
 }
diff --git a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.stderr b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.stderr
index 7b63e72acbf..7e1a8f083ac 100644
--- a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.stderr
+++ b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.stderr
@@ -1,12 +1,12 @@
 error[E0491]: in type `&'static &()`, reference has a longer lifetime than the data it references
-  --> $DIR/rpitit-hidden-types-self-implied-wf.rs:8:27
+  --> $DIR/rpitit-hidden-types-self-implied-wf.rs:6:27
    |
 LL |     fn extend(s: &str) -> (Option<&'static &'_ ()>, &'static str) {
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: the pointer is valid for the static lifetime
 note: but the referenced data is only valid for the anonymous lifetime defined here
-  --> $DIR/rpitit-hidden-types-self-implied-wf.rs:8:18
+  --> $DIR/rpitit-hidden-types-self-implied-wf.rs:6:18
    |
 LL |     fn extend(s: &str) -> (Option<&'static &'_ ()>, &'static str) {
    |                  ^^^^
diff --git a/tests/ui/impl-trait/in-trait/rpitit-shadowed-by-missing-adt.rs b/tests/ui/impl-trait/in-trait/rpitit-shadowed-by-missing-adt.rs
index 44a2b430344..b9fe8d8bfc5 100644
--- a/tests/ui/impl-trait/in-trait/rpitit-shadowed-by-missing-adt.rs
+++ b/tests/ui/impl-trait/in-trait/rpitit-shadowed-by-missing-adt.rs
@@ -1,6 +1,6 @@
 // issue: 113903
 
-#![feature(return_position_impl_trait_in_trait, lint_reasons)]
+#![feature(lint_reasons)]
 
 use std::ops::Deref;
 
diff --git a/tests/ui/impl-trait/in-trait/sibling-function-constraint.rs b/tests/ui/impl-trait/in-trait/sibling-function-constraint.rs
new file mode 100644
index 00000000000..fe162e6cf80
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/sibling-function-constraint.rs
@@ -0,0 +1,21 @@
+// Checks that a sibling function (i.e. `foo`) cannot constrain
+// an RPITIT from another function (`bar`).
+
+trait Trait {
+    fn foo();
+
+    fn bar() -> impl Sized;
+}
+
+impl Trait for () {
+    fn foo() {
+        let _: String = Self::bar();
+        //~^ ERROR mismatched types
+    }
+
+    fn bar() -> impl Sized {
+        loop {}
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/in-trait/sibling-function-constraint.stderr b/tests/ui/impl-trait/in-trait/sibling-function-constraint.stderr
new file mode 100644
index 00000000000..729963a8141
--- /dev/null
+++ b/tests/ui/impl-trait/in-trait/sibling-function-constraint.stderr
@@ -0,0 +1,17 @@
+error[E0308]: mismatched types
+  --> $DIR/sibling-function-constraint.rs:12:25
+   |
+LL |         let _: String = Self::bar();
+   |                ------   ^^^^^^^^^^^ expected `String`, found opaque type
+   |                |
+   |                expected due to this
+...
+LL |     fn bar() -> impl Sized {
+   |                 ---------- the found opaque type
+   |
+   = note:   expected struct `String`
+           found opaque type `impl Sized`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/impl-trait/in-trait/signature-mismatch.rs b/tests/ui/impl-trait/in-trait/signature-mismatch.rs
index 685c0f06e88..d85ee5fc704 100644
--- a/tests/ui/impl-trait/in-trait/signature-mismatch.rs
+++ b/tests/ui/impl-trait/in-trait/signature-mismatch.rs
@@ -2,7 +2,7 @@
 // revisions: success failure
 //[success] check-pass
 
-#![feature(return_position_impl_trait_in_trait, lint_reasons)]
+#![feature(lint_reasons)]
 
 use std::future::Future;
 
diff --git a/tests/ui/impl-trait/in-trait/specialization-broken.rs b/tests/ui/impl-trait/in-trait/specialization-broken.rs
index 2fcffdf3f9a..a06cd814f7c 100644
--- a/tests/ui/impl-trait/in-trait/specialization-broken.rs
+++ b/tests/ui/impl-trait/in-trait/specialization-broken.rs
@@ -2,7 +2,6 @@
 // But we fixed an ICE anyways.
 
 #![feature(specialization)]
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 trait Foo {
diff --git a/tests/ui/impl-trait/in-trait/specialization-broken.stderr b/tests/ui/impl-trait/in-trait/specialization-broken.stderr
index dc621d6b8a8..1d169b5d690 100644
--- a/tests/ui/impl-trait/in-trait/specialization-broken.stderr
+++ b/tests/ui/impl-trait/in-trait/specialization-broken.stderr
@@ -1,5 +1,5 @@
 error[E0053]: method `bar` has an incompatible type for trait
-  --> $DIR/specialization-broken.rs:16:22
+  --> $DIR/specialization-broken.rs:15:22
    |
 LL | default impl<U> Foo for U
    |              - this type parameter
@@ -11,7 +11,7 @@ LL |     fn bar(&self) -> U {
    |                      help: change the output type to match the trait: `impl Sized`
    |
 note: type in trait
-  --> $DIR/specialization-broken.rs:9:22
+  --> $DIR/specialization-broken.rs:8:22
    |
 LL |     fn bar(&self) -> impl Sized;
    |                      ^^^^^^^^^^
@@ -19,12 +19,12 @@ LL |     fn bar(&self) -> impl Sized;
               found signature `fn(&U) -> U`
 
 error: method with return-position `impl Trait` in trait cannot be specialized
-  --> $DIR/specialization-broken.rs:16:5
+  --> $DIR/specialization-broken.rs:15:5
    |
 LL |     fn bar(&self) -> U {
    |     ^^^^^^^^^^^^^^^^^^
    |
-   = note: specialization behaves in inconsistent and surprising ways with `#![feature(return_position_impl_trait_in_trait)]`, and for now is disallowed
+   = note: specialization behaves in inconsistent and surprising ways with return position `impl Trait` in traits, and for now is disallowed
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/impl-trait/in-trait/specialization-substs-remap.rs b/tests/ui/impl-trait/in-trait/specialization-substs-remap.rs
index 41fc285883a..05386632758 100644
--- a/tests/ui/impl-trait/in-trait/specialization-substs-remap.rs
+++ b/tests/ui/impl-trait/in-trait/specialization-substs-remap.rs
@@ -1,7 +1,7 @@
 // check-pass
 
 #![feature(specialization)]
-#![feature(return_position_impl_trait_in_trait, lint_reasons)]
+#![feature(lint_reasons)]
 #![allow(incomplete_features)]
 
 pub trait Foo {
diff --git a/tests/ui/impl-trait/in-trait/success.rs b/tests/ui/impl-trait/in-trait/success.rs
index 7d415ea17a4..eb2349feb29 100644
--- a/tests/ui/impl-trait/in-trait/success.rs
+++ b/tests/ui/impl-trait/in-trait/success.rs
@@ -1,6 +1,6 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait, lint_reasons)]
+#![feature(lint_reasons)]
 #![allow(incomplete_features)]
 
 use std::fmt::Display;
diff --git a/tests/ui/impl-trait/in-trait/suggest-missing-item.fixed b/tests/ui/impl-trait/in-trait/suggest-missing-item.fixed
index 58d83384a23..8dc8e045d47 100644
--- a/tests/ui/impl-trait/in-trait/suggest-missing-item.fixed
+++ b/tests/ui/impl-trait/in-trait/suggest-missing-item.fixed
@@ -1,8 +1,6 @@
 // edition:2021
 // run-rustfix
 
-#![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
-
 trait Trait {
     #[allow(async_fn_in_trait)]
     async fn foo();
diff --git a/tests/ui/impl-trait/in-trait/suggest-missing-item.rs b/tests/ui/impl-trait/in-trait/suggest-missing-item.rs
index c27229806e1..30b04d87b9a 100644
--- a/tests/ui/impl-trait/in-trait/suggest-missing-item.rs
+++ b/tests/ui/impl-trait/in-trait/suggest-missing-item.rs
@@ -1,8 +1,6 @@
 // edition:2021
 // run-rustfix
 
-#![feature(async_fn_in_trait, return_position_impl_trait_in_trait)]
-
 trait Trait {
     #[allow(async_fn_in_trait)]
     async fn foo();
diff --git a/tests/ui/impl-trait/in-trait/suggest-missing-item.stderr b/tests/ui/impl-trait/in-trait/suggest-missing-item.stderr
index 29f6bad86dc..cec94e39a35 100644
--- a/tests/ui/impl-trait/in-trait/suggest-missing-item.stderr
+++ b/tests/ui/impl-trait/in-trait/suggest-missing-item.stderr
@@ -1,5 +1,5 @@
 error[E0046]: not all trait items implemented, missing: `foo`, `bar`, `test`, `baz`
-  --> $DIR/suggest-missing-item.rs:21:1
+  --> $DIR/suggest-missing-item.rs:19:1
    |
 LL |     async fn foo();
    |     --------------- `foo` from trait
diff --git a/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.rs b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.rs
index 0bbe50ea6fd..c905bfce852 100644
--- a/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.rs
+++ b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 struct S;
diff --git a/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.stderr b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.stderr
index 8ff54cad951..e904548742d 100644
--- a/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.stderr
+++ b/tests/ui/impl-trait/in-trait/trait-more-generics-than-impl.stderr
@@ -1,5 +1,5 @@
 error[E0049]: method `bar` has 0 type parameters but its trait declaration has 1 type parameter
-  --> $DIR/trait-more-generics-than-impl.rs:11:11
+  --> $DIR/trait-more-generics-than-impl.rs:10:11
    |
 LL |     fn bar<T>() -> impl Sized;
    |            - expected 1 type parameter
diff --git a/tests/ui/impl-trait/in-trait/unconstrained-lt.rs b/tests/ui/impl-trait/in-trait/unconstrained-lt.rs
index 07c8606f9fe..ff3753de5a2 100644
--- a/tests/ui/impl-trait/in-trait/unconstrained-lt.rs
+++ b/tests/ui/impl-trait/in-trait/unconstrained-lt.rs
@@ -1,5 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
-
 trait Foo {
     fn test() -> impl Sized;
 }
diff --git a/tests/ui/impl-trait/in-trait/unconstrained-lt.stderr b/tests/ui/impl-trait/in-trait/unconstrained-lt.stderr
index cfce3556720..61a0f8454d1 100644
--- a/tests/ui/impl-trait/in-trait/unconstrained-lt.stderr
+++ b/tests/ui/impl-trait/in-trait/unconstrained-lt.stderr
@@ -1,5 +1,5 @@
 error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/unconstrained-lt.rs:7:6
+  --> $DIR/unconstrained-lt.rs:5:6
    |
 LL | impl<'a, T> Foo for T {
    |      ^^ unconstrained lifetime parameter
diff --git a/tests/ui/impl-trait/in-trait/variance.rs b/tests/ui/impl-trait/in-trait/variance.rs
index f8e4ab88c19..65565dcc2a6 100644
--- a/tests/ui/impl-trait/in-trait/variance.rs
+++ b/tests/ui/impl-trait/in-trait/variance.rs
@@ -1,4 +1,4 @@
-#![feature(rustc_attrs, return_position_impl_trait_in_trait)]
+#![feature(rustc_attrs)]
 #![allow(internal_features)]
 #![rustc_variance_of_opaques]
 
diff --git a/tests/ui/impl-trait/in-trait/variances-of-gat.rs b/tests/ui/impl-trait/in-trait/variances-of-gat.rs
index 0d19e1ff416..aabb6f830ed 100644
--- a/tests/ui/impl-trait/in-trait/variances-of-gat.rs
+++ b/tests/ui/impl-trait/in-trait/variances-of-gat.rs
@@ -1,6 +1,5 @@
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait)]
 
 trait Foo {}
 
diff --git a/tests/ui/impl-trait/in-trait/wf-bounds.rs b/tests/ui/impl-trait/in-trait/wf-bounds.rs
index ee873f94b26..f1e372b196a 100644
--- a/tests/ui/impl-trait/in-trait/wf-bounds.rs
+++ b/tests/ui/impl-trait/in-trait/wf-bounds.rs
@@ -1,6 +1,5 @@
 // issue #101663
 
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Display;
diff --git a/tests/ui/impl-trait/in-trait/wf-bounds.stderr b/tests/ui/impl-trait/in-trait/wf-bounds.stderr
index 4d60b133048..c20df9b40ed 100644
--- a/tests/ui/impl-trait/in-trait/wf-bounds.stderr
+++ b/tests/ui/impl-trait/in-trait/wf-bounds.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
-  --> $DIR/wf-bounds.rs:15:22
+  --> $DIR/wf-bounds.rs:14:22
    |
 LL |     fn nya() -> impl Wf<Vec<[u8]>>;
    |                      ^^^^^^^^^^^^^ doesn't have a size known at compile-time
@@ -9,14 +9,14 @@ note: required by a bound in `Vec`
   --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
 
 error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
-  --> $DIR/wf-bounds.rs:18:23
+  --> $DIR/wf-bounds.rs:17:23
    |
 LL |     fn nya2() -> impl Wf<[u8]>;
    |                       ^^^^^^^^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `[u8]`
 note: required by a bound in `Wf`
-  --> $DIR/wf-bounds.rs:8:10
+  --> $DIR/wf-bounds.rs:7:10
    |
 LL | trait Wf<T> {
    |          ^ required by this bound in `Wf`
@@ -26,7 +26,7 @@ LL | trait Wf<T: ?Sized> {
    |           ++++++++
 
 error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
-  --> $DIR/wf-bounds.rs:21:44
+  --> $DIR/wf-bounds.rs:20:44
    |
 LL |     fn nya3() -> impl Wf<(), Output = impl Wf<Vec<[u8]>>>;
    |                                            ^^^^^^^^^^^^^ doesn't have a size known at compile-time
@@ -36,14 +36,14 @@ note: required by a bound in `Vec`
   --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
 
 error[E0277]: `T` doesn't implement `std::fmt::Display`
-  --> $DIR/wf-bounds.rs:24:26
+  --> $DIR/wf-bounds.rs:23:26
    |
 LL |     fn nya4<T>() -> impl Wf<NeedsDisplay<T>>;
    |                          ^^^^^^^^^^^^^^^^^^^ `T` cannot be formatted with the default formatter
    |
    = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
 note: required by a bound in `NeedsDisplay`
-  --> $DIR/wf-bounds.rs:12:24
+  --> $DIR/wf-bounds.rs:11:24
    |
 LL | struct NeedsDisplay<T: Display>(T);
    |                        ^^^^^^^ required by this bound in `NeedsDisplay`
diff --git a/tests/ui/impl-trait/in-trait/where-clause.rs b/tests/ui/impl-trait/in-trait/where-clause.rs
index 87bac519cf3..f7f4980b730 100644
--- a/tests/ui/impl-trait/in-trait/where-clause.rs
+++ b/tests/ui/impl-trait/in-trait/where-clause.rs
@@ -1,7 +1,6 @@
 // check-pass
 // edition: 2021
 
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 use std::fmt::Debug;
diff --git a/tests/ui/impl-trait/static-lifetime-return-position-impl-trait.rs b/tests/ui/impl-trait/static-lifetime-return-position-impl-trait.rs
index 98dbaf036be..91a0e0d4829 100644
--- a/tests/ui/impl-trait/static-lifetime-return-position-impl-trait.rs
+++ b/tests/ui/impl-trait/static-lifetime-return-position-impl-trait.rs
@@ -1,7 +1,7 @@
 // check-pass
 
 #![allow(incomplete_features)]
-#![feature(adt_const_params, return_position_impl_trait_in_trait)]
+#![feature(adt_const_params)]
 
 pub struct Element;
 
diff --git a/tests/ui/impl-trait/where-allowed.rs b/tests/ui/impl-trait/where-allowed.rs
index d3fab326e74..158dc5ab974 100644
--- a/tests/ui/impl-trait/where-allowed.rs
+++ b/tests/ui/impl-trait/where-allowed.rs
@@ -104,10 +104,9 @@ trait InTraitDefnParameters {
     fn in_parameters(_: impl Debug);
 }
 
-// Disallowed
+// Allowed
 trait InTraitDefnReturn {
     fn in_return() -> impl Debug;
-    //~^ ERROR `impl Trait` only allowed in function and inherent method argument and return types
 }
 
 // Allowed and disallowed in trait impls
@@ -124,7 +123,7 @@ impl DummyTrait for () {
     // Allowed
 
     fn in_trait_impl_return() -> impl Debug { () }
-    //~^ ERROR `impl Trait` only allowed in function and inherent method argument and return types
+    // Allowed
 }
 
 // Allowed
diff --git a/tests/ui/impl-trait/where-allowed.stderr b/tests/ui/impl-trait/where-allowed.stderr
index bd7c9a94793..2d8895030f2 100644
--- a/tests/ui/impl-trait/where-allowed.stderr
+++ b/tests/ui/impl-trait/where-allowed.stderr
@@ -17,7 +17,7 @@ LL | fn in_impl_Fn_parameter_in_return() -> &'static impl Fn(impl Debug) { panic
    |                                                 outer `impl Trait`
 
 error[E0658]: `impl Trait` in associated types is unstable
-  --> $DIR/where-allowed.rs:120:16
+  --> $DIR/where-allowed.rs:119:16
    |
 LL |     type Out = impl Debug;
    |                ^^^^^^^^^^
@@ -26,7 +26,7 @@ LL |     type Out = impl Debug;
    = help: add `#![feature(impl_trait_in_assoc_type)]` to the crate attributes to enable
 
 error[E0658]: `impl Trait` in type aliases is unstable
-  --> $DIR/where-allowed.rs:155:23
+  --> $DIR/where-allowed.rs:154:23
    |
 LL | type InTypeAlias<R> = impl Debug;
    |                       ^^^^^^^^^^
@@ -35,7 +35,7 @@ LL | type InTypeAlias<R> = impl Debug;
    = help: add `#![feature(type_alias_impl_trait)]` to the crate attributes to enable
 
 error[E0658]: `impl Trait` in type aliases is unstable
-  --> $DIR/where-allowed.rs:158:39
+  --> $DIR/where-allowed.rs:157:39
    |
 LL | type InReturnInTypeAlias<R> = fn() -> impl Debug;
    |                                       ^^^^^^^^^^
@@ -145,146 +145,128 @@ error[E0562]: `impl Trait` only allowed in function and inherent method argument
 LL |     InTupleVariant(impl Debug),
    |                    ^^^^^^^^^^
 
-error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in trait method return types
-  --> $DIR/where-allowed.rs:109:23
-   |
-LL |     fn in_return() -> impl Debug;
-   |                       ^^^^^^^^^^
-   |
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
-
-error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in `impl` method return types
-  --> $DIR/where-allowed.rs:126:34
-   |
-LL |     fn in_trait_impl_return() -> impl Debug { () }
-   |                                  ^^^^^^^^^^
-   |
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(return_position_impl_trait_in_trait)]` to the crate attributes to enable
-
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in `extern fn` params
-  --> $DIR/where-allowed.rs:139:33
+  --> $DIR/where-allowed.rs:138:33
    |
 LL |     fn in_foreign_parameters(_: impl Debug);
    |                                 ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in `extern fn` return types
-  --> $DIR/where-allowed.rs:142:31
+  --> $DIR/where-allowed.rs:141:31
    |
 LL |     fn in_foreign_return() -> impl Debug;
    |                               ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in `fn` pointer return types
-  --> $DIR/where-allowed.rs:158:39
+  --> $DIR/where-allowed.rs:157:39
    |
 LL | type InReturnInTypeAlias<R> = fn() -> impl Debug;
    |                                       ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in traits
-  --> $DIR/where-allowed.rs:163:16
+  --> $DIR/where-allowed.rs:162:16
    |
 LL | impl PartialEq<impl Debug> for () {
    |                ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in impl headers
-  --> $DIR/where-allowed.rs:168:24
+  --> $DIR/where-allowed.rs:167:24
    |
 LL | impl PartialEq<()> for impl Debug {
    |                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in impl headers
-  --> $DIR/where-allowed.rs:173:6
+  --> $DIR/where-allowed.rs:172:6
    |
 LL | impl impl Debug {
    |      ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in impl headers
-  --> $DIR/where-allowed.rs:179:24
+  --> $DIR/where-allowed.rs:178:24
    |
 LL | impl InInherentImplAdt<impl Debug> {
    |                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in bounds
-  --> $DIR/where-allowed.rs:185:11
+  --> $DIR/where-allowed.rs:184:11
    |
 LL |     where impl Debug: Debug
    |           ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in bounds
-  --> $DIR/where-allowed.rs:192:15
+  --> $DIR/where-allowed.rs:191:15
    |
 LL |     where Vec<impl Debug>: Debug
    |               ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in bounds
-  --> $DIR/where-allowed.rs:199:24
+  --> $DIR/where-allowed.rs:198:24
    |
 LL |     where T: PartialEq<impl Debug>
    |                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in `Fn` trait params
-  --> $DIR/where-allowed.rs:206:17
+  --> $DIR/where-allowed.rs:205:17
    |
 LL |     where T: Fn(impl Debug)
    |                 ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in `Fn` trait return types
-  --> $DIR/where-allowed.rs:213:22
+  --> $DIR/where-allowed.rs:212:22
    |
 LL |     where T: Fn() -> impl Debug
    |                      ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:219:40
+  --> $DIR/where-allowed.rs:218:40
    |
 LL | struct InStructGenericParamDefault<T = impl Debug>(T);
    |                                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:223:36
+  --> $DIR/where-allowed.rs:222:36
    |
 LL | enum InEnumGenericParamDefault<T = impl Debug> { Variant(T) }
    |                                    ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:227:38
+  --> $DIR/where-allowed.rs:226:38
    |
 LL | trait InTraitGenericParamDefault<T = impl Debug> {}
    |                                      ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:231:41
+  --> $DIR/where-allowed.rs:230:41
    |
 LL | type InTypeAliasGenericParamDefault<T = impl Debug> = T;
    |                                         ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:235:11
+  --> $DIR/where-allowed.rs:234:11
    |
 LL | impl <T = impl Debug> T {}
    |           ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in generic parameter defaults
-  --> $DIR/where-allowed.rs:242:40
+  --> $DIR/where-allowed.rs:241:40
    |
 LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    |                                        ^^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in variable bindings
-  --> $DIR/where-allowed.rs:248:29
+  --> $DIR/where-allowed.rs:247:29
    |
 LL |     let _in_local_variable: impl Fn() = || {};
    |                             ^^^^^^^^^
 
 error[E0562]: `impl Trait` only allowed in function and inherent method argument and return types, not in closure return types
-  --> $DIR/where-allowed.rs:250:46
+  --> $DIR/where-allowed.rs:249:46
    |
 LL |     let _in_return_in_local_variable = || -> impl Fn() { || {} };
    |                                              ^^^^^^^^^
 
 error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
-  --> $DIR/where-allowed.rs:235:7
+  --> $DIR/where-allowed.rs:234:7
    |
 LL | impl <T = impl Debug> T {}
    |       ^^^^^^^^^^^^^^
@@ -294,7 +276,7 @@ LL | impl <T = impl Debug> T {}
    = note: `#[deny(invalid_type_param_default)]` on by default
 
 error: defaults for type parameters are only allowed in `struct`, `enum`, `type`, or `trait` definitions
-  --> $DIR/where-allowed.rs:242:36
+  --> $DIR/where-allowed.rs:241:36
    |
 LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    |                                    ^^^^^^^^^^^^^^
@@ -303,14 +285,14 @@ LL | fn in_method_generic_param_default<T = impl Debug>(_: T) {}
    = note: for more information, see issue #36887 <https://github.com/rust-lang/rust/issues/36887>
 
 error[E0118]: no nominal type found for inherent implementation
-  --> $DIR/where-allowed.rs:235:1
+  --> $DIR/where-allowed.rs:234:1
    |
 LL | impl <T = impl Debug> T {}
    | ^^^^^^^^^^^^^^^^^^^^^^^ impl requires a nominal type
    |
    = note: either implement a trait on it or create a newtype to wrap it instead
 
-error: aborting due to 47 previous errors
+error: aborting due to 45 previous errors
 
 Some errors have detailed explanations: E0118, E0562, E0658, E0666.
 For more information about an error, try `rustc --explain E0118`.
diff --git a/tests/ui/parser/fn-header-semantic-fail.rs b/tests/ui/parser/fn-header-semantic-fail.rs
index 71f18a27e7c..f8b58cad7c1 100644
--- a/tests/ui/parser/fn-header-semantic-fail.rs
+++ b/tests/ui/parser/fn-header-semantic-fail.rs
@@ -13,25 +13,23 @@ fn main() {
     //~^ ERROR functions cannot be both `const` and `async`
 
     trait X {
-        async fn ft1(); //~ ERROR functions in traits cannot be declared `async`
+        async fn ft1(); // OK.
         unsafe fn ft2(); // OK.
         const fn ft3(); //~ ERROR functions in traits cannot be declared const
         extern "C" fn ft4(); // OK.
         const async unsafe extern "C" fn ft5();
-        //~^ ERROR functions in traits cannot be declared `async`
-        //~| ERROR functions in traits cannot be declared const
+        //~^ ERROR functions in traits cannot be declared const
         //~| ERROR functions cannot be both `const` and `async`
     }
 
     struct Y;
     impl X for Y {
-        async fn ft1() {} //~ ERROR functions in traits cannot be declared `async`
+        async fn ft1() {} // OK.
         unsafe fn ft2() {} // OK.
         const fn ft3() {} //~ ERROR functions in traits cannot be declared const
         extern "C" fn ft4() {}
         const async unsafe extern "C" fn ft5() {}
-        //~^ ERROR functions in traits cannot be declared `async`
-        //~| ERROR functions in traits cannot be declared const
+        //~^ ERROR functions in traits cannot be declared const
         //~| ERROR functions cannot be both `const` and `async`
     }
 
diff --git a/tests/ui/parser/fn-header-semantic-fail.stderr b/tests/ui/parser/fn-header-semantic-fail.stderr
index 7f7b7e835f8..cdf01e0c5df 100644
--- a/tests/ui/parser/fn-header-semantic-fail.stderr
+++ b/tests/ui/parser/fn-header-semantic-fail.stderr
@@ -29,19 +29,19 @@ LL |         const async unsafe extern "C" fn ft5();
    |         `const` because of this
 
 error[E0379]: functions in traits cannot be declared const
-  --> $DIR/fn-header-semantic-fail.rs:30:9
+  --> $DIR/fn-header-semantic-fail.rs:29:9
    |
 LL |         const fn ft3() {}
    |         ^^^^^ functions in traits cannot be const
 
 error[E0379]: functions in traits cannot be declared const
-  --> $DIR/fn-header-semantic-fail.rs:32:9
+  --> $DIR/fn-header-semantic-fail.rs:31:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
    |         ^^^^^ functions in traits cannot be const
 
 error: functions cannot be both `const` and `async`
-  --> $DIR/fn-header-semantic-fail.rs:32:9
+  --> $DIR/fn-header-semantic-fail.rs:31:9
    |
 LL |         const async unsafe extern "C" fn ft5() {}
    |         ^^^^^-^^^^^------------------------------
@@ -50,7 +50,7 @@ LL |         const async unsafe extern "C" fn ft5() {}
    |         `const` because of this
 
 error: functions cannot be both `const` and `async`
-  --> $DIR/fn-header-semantic-fail.rs:43:9
+  --> $DIR/fn-header-semantic-fail.rs:41:9
    |
 LL |         const async unsafe extern "C" fn fi5() {}
    |         ^^^^^-^^^^^------------------------------
@@ -59,7 +59,7 @@ LL |         const async unsafe extern "C" fn fi5() {}
    |         `const` because of this
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:48:18
+  --> $DIR/fn-header-semantic-fail.rs:46:18
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -72,7 +72,7 @@ LL |         fn fe1();
    |         ~~
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:49:19
+  --> $DIR/fn-header-semantic-fail.rs:47:19
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -86,7 +86,7 @@ LL |         fn fe2();
    |         ~~
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:50:18
+  --> $DIR/fn-header-semantic-fail.rs:48:18
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -100,7 +100,7 @@ LL |         fn fe3();
    |         ~~
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:51:23
+  --> $DIR/fn-header-semantic-fail.rs:49:23
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -114,7 +114,7 @@ LL |         fn fe4();
    |         ~~
 
 error: functions in `extern` blocks cannot have qualifiers
-  --> $DIR/fn-header-semantic-fail.rs:52:42
+  --> $DIR/fn-header-semantic-fail.rs:50:42
    |
 LL |     extern "C" {
    |     ---------- in this `extern` block
@@ -128,7 +128,7 @@ LL |         fn fe5();
    |         ~~
 
 error: functions cannot be both `const` and `async`
-  --> $DIR/fn-header-semantic-fail.rs:52:9
+  --> $DIR/fn-header-semantic-fail.rs:50:9
    |
 LL |         const async unsafe extern "C" fn fe5();
    |         ^^^^^-^^^^^----------------------------
@@ -136,59 +136,6 @@ LL |         const async unsafe extern "C" fn fe5();
    |         |     `async` because of this
    |         `const` because of this
 
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/fn-header-semantic-fail.rs:16:9
-   |
-LL |         async fn ft1();
-   |         -----^^^^^^^^^^
-   |         |
-   |         `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/fn-header-semantic-fail.rs:20:9
-   |
-LL |         const async unsafe extern "C" fn ft5();
-   |         ^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |               |
-   |               `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/fn-header-semantic-fail.rs:28:9
-   |
-LL |         async fn ft1() {}
-   |         -----^^^^^^^^^
-   |         |
-   |         `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/fn-header-semantic-fail.rs:32:9
-   |
-LL |         const async unsafe extern "C" fn ft5() {}
-   |         ^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |               |
-   |               `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 18 previous errors
+error: aborting due to 14 previous errors
 
-Some errors have detailed explanations: E0379, E0706.
-For more information about an error, try `rustc --explain E0379`.
+For more information about this error, try `rustc --explain E0379`.
diff --git a/tests/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs b/tests/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs
index 49462f52fb4..927ecd9aee0 100644
--- a/tests/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs
+++ b/tests/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs
@@ -9,11 +9,9 @@ impl A {
 
 trait B {
     async fn associated();
-    //~^ ERROR cannot be declared `async`
 }
 impl B for A {
     async fn associated(); //~ ERROR without body
-    //~^ ERROR cannot be declared `async`
 }
 
 fn main() {}
diff --git a/tests/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr b/tests/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr
index 1354abb4f14..da9eeea954a 100644
--- a/tests/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr
+++ b/tests/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr
@@ -15,39 +15,12 @@ LL |     async fn inherent();
    |                        help: provide a definition for the function: `{ <body> }`
 
 error: associated function in `impl` without body
-  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:15:5
+  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:14:5
    |
 LL |     async fn associated();
    |     ^^^^^^^^^^^^^^^^^^^^^-
    |                          |
    |                          help: provide a definition for the function: `{ <body> }`
 
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:11:5
-   |
-LL |     async fn associated();
-   |     -----^^^^^^^^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error[E0706]: functions in traits cannot be declared `async`
-  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:15:5
-   |
-LL |     async fn associated();
-   |     -----^^^^^^^^^^^^^^^^^
-   |     |
-   |     `async` because of this
-   |
-   = note: `async` trait functions are not currently supported
-   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
-   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
-   = help: add `#![feature(async_fn_in_trait)]` to the crate attributes to enable
-
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0706`.
diff --git a/tests/ui/rfcs/rfc-1937-termination-trait/issue-103052-2.rs b/tests/ui/rfcs/rfc-1937-termination-trait/issue-103052-2.rs
index 77227ebd834..1933a68c221 100644
--- a/tests/ui/rfcs/rfc-1937-termination-trait/issue-103052-2.rs
+++ b/tests/ui/rfcs/rfc-1937-termination-trait/issue-103052-2.rs
@@ -1,4 +1,3 @@
-#![feature(return_position_impl_trait_in_trait)]
 #![allow(incomplete_features)]
 
 mod child {
diff --git a/tests/ui/rfcs/rfc-1937-termination-trait/issue-103052-2.stderr b/tests/ui/rfcs/rfc-1937-termination-trait/issue-103052-2.stderr
index c4371a0024c..40f736c215d 100644
--- a/tests/ui/rfcs/rfc-1937-termination-trait/issue-103052-2.stderr
+++ b/tests/ui/rfcs/rfc-1937-termination-trait/issue-103052-2.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `Something: Termination` is not satisfied
-  --> $DIR/issue-103052-2.rs:12:22
+  --> $DIR/issue-103052-2.rs:11:22
    |
 LL |         fn main() -> Something {
    |                      ^^^^^^^^^ the trait `Termination` is not implemented for `Something`
    |
 note: required by a bound in `Main::{opaque#0}`
-  --> $DIR/issue-103052-2.rs:6:27
+  --> $DIR/issue-103052-2.rs:5:27
    |
 LL |         fn main() -> impl std::process::Termination;
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Main::{opaque#0}`
diff --git a/tests/ui/rfcs/rfc-2632-const-trait-impl/const-impl-trait.rs b/tests/ui/rfcs/rfc-2632-const-trait-impl/const-impl-trait.rs
index f396deff4fe..8e4de57b019 100644
--- a/tests/ui/rfcs/rfc-2632-const-trait-impl/const-impl-trait.rs
+++ b/tests/ui/rfcs/rfc-2632-const-trait-impl/const-impl-trait.rs
@@ -4,7 +4,6 @@
     associated_type_bounds,
     const_trait_impl,
     const_cmp,
-    return_position_impl_trait_in_trait,
 )]
 
 use std::marker::Destruct;
diff --git a/tests/ui/rfcs/rfc-2632-const-trait-impl/const-impl-trait.stderr b/tests/ui/rfcs/rfc-2632-const-trait-impl/const-impl-trait.stderr
index f9078e22791..4a9090d0b53 100644
--- a/tests/ui/rfcs/rfc-2632-const-trait-impl/const-impl-trait.stderr
+++ b/tests/ui/rfcs/rfc-2632-const-trait-impl/const-impl-trait.stderr
@@ -5,31 +5,31 @@ LL |     const_cmp,
    |     ^^^^^^^^^
 
 error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:12:30
+  --> $DIR/const-impl-trait.rs:11:30
    |
 LL | const fn cmp(a: &impl ~const PartialEq) -> bool {
    |                              ^^^^^^^^^
 
 error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:16:30
+  --> $DIR/const-impl-trait.rs:15:30
    |
 LL | const fn wrap(x: impl ~const PartialEq + ~const Destruct)
    |                              ^^^^^^^^^
 
 error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:17:20
+  --> $DIR/const-impl-trait.rs:16:20
    |
 LL |     -> impl ~const PartialEq + ~const Destruct
    |                    ^^^^^^^^^
 
 error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:24:29
+  --> $DIR/const-impl-trait.rs:23:29
    |
 LL |     fn huh() -> impl ~const PartialEq + ~const Destruct + Copy;
    |                             ^^^^^^^^^
 
 error: ~const can only be applied to `#[const_trait]` traits
-  --> $DIR/const-impl-trait.rs:28:29
+  --> $DIR/const-impl-trait.rs:27:29
    |
 LL |     fn huh() -> impl ~const PartialEq + ~const Destruct + Copy {
    |                             ^^^^^^^^^
diff --git a/tests/ui/traits/new-solver/deduce-closure-signature-after-normalization.rs b/tests/ui/traits/new-solver/deduce-closure-signature-after-normalization.rs
index d67fc65032c..51f62bc2312 100644
--- a/tests/ui/traits/new-solver/deduce-closure-signature-after-normalization.rs
+++ b/tests/ui/traits/new-solver/deduce-closure-signature-after-normalization.rs
@@ -1,8 +1,6 @@
 // compile-flags: -Ztrait-solver=next
 // check-pass
 
-#![feature(return_position_impl_trait_in_trait)]
-
 trait Foo {
     fn test() -> impl Fn(u32) -> u32 {
         |x| x.count_ones()
diff --git a/tests/ui/traits/new-solver/normalize-async-closure-in-trait.rs b/tests/ui/traits/new-solver/normalize-async-closure-in-trait.rs
index b6200096a89..cc16cc87169 100644
--- a/tests/ui/traits/new-solver/normalize-async-closure-in-trait.rs
+++ b/tests/ui/traits/new-solver/normalize-async-closure-in-trait.rs
@@ -2,8 +2,6 @@
 // check-pass
 // edition:2021
 
-#![feature(async_fn_in_trait)]
-
 trait Foo {
     async fn bar() {}
 }