Point to full async fn for future

compiler/rustc_ast_lowering/src/lib.rs

@@ -1824,7 +1824,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
  }
 
  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)
+ self.lower_async_fn_ret_ty(&decl.output, fn_def_id, ret_id, kind, fn_span)
  } else {
  match &decl.output {
  FnRetTy::Ty(ty) => {
@@ -1901,8 +1901,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
  fn_def_id: LocalDefId,
  opaque_ty_node_id: NodeId,
  fn_kind: FnDeclKind,
+ fn_span: Span,
  ) -> hir::FnRetTy<'hir> {
- let span = self.lower_span(output.span());
+ let span = self.lower_span(fn_span);
  let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::Async, span, None);
 
  let captured_lifetimes: Vec<_> = self

src/tools/clippy/tests/ui/crashes/ice-10645.stderr

@@ -1,8 +1,8 @@
 warning: future cannot be sent between threads safely
- --> $DIR/ice-10645.rs:5:35
+ --> $DIR/ice-10645.rs:5:1
  |
 LL | pub async fn bar<'a, T: 'a>(_: T) {}
- |  ^ future returned by `bar` is not `Send`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ future returned by `bar` is not `Send`
  |
 note: captured value is not `Send`
  --> $DIR/ice-10645.rs:5:29

src/tools/clippy/tests/ui/future_not_send.stderr

@@ -1,8 +1,8 @@
 error: future cannot be sent between threads safely
- --> $DIR/future_not_send.rs:7:62
+ --> $DIR/future_not_send.rs:7:1
  |
 LL | async fn private_future(rc: Rc<[u8]>, cell: &Cell<usize>) -> bool {
- |  ^^^^ future returned by `private_future` is not `Send`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ future returned by `private_future` is not `Send`
  |
 note: future is not `Send` as this value is used across an await
  --> $DIR/future_not_send.rs:9:20
@@ -23,10 +23,10 @@ LL | async fn private_future(rc: Rc<[u8]>, cell: &Cell<usize>) -> bool {
  = help: to override `-D warnings` add `#[allow(clippy::future_not_send)]`
 
 error: future cannot be sent between threads safely
- --> $DIR/future_not_send.rs:12:42
+ --> $DIR/future_not_send.rs:12:1
  |
 LL | pub async fn public_future(rc: Rc<[u8]>) {
- |  ^ future returned by `public_future` is not `Send`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ future returned by `public_future` is not `Send`
  |
 note: future is not `Send` as this value is used across an await
  --> $DIR/future_not_send.rs:14:20
@@ -39,10 +39,10 @@ LL | async { true }.await;
  = note: `std::rc::Rc<[u8]>` doesn't implement `std::marker::Send`
 
 error: future cannot be sent between threads safely
- --> $DIR/future_not_send.rs:21:63
+ --> $DIR/future_not_send.rs:21:1
  |
 LL | async fn private_future2(rc: Rc<[u8]>, cell: &Cell<usize>) -> bool {
- |  ^^^^ future returned by `private_future2` is not `Send`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ future returned by `private_future2` is not `Send`
  |
 note: captured value is not `Send`
  --> $DIR/future_not_send.rs:21:26
@@ -58,10 +58,10 @@ LL | async fn private_future2(rc: Rc<[u8]>, cell: &Cell<usize>) -> bool {
  = note: `std::cell::Cell<usize>` doesn't implement `std::marker::Sync`
 
 error: future cannot be sent between threads safely
- --> $DIR/future_not_send.rs:26:43
+ --> $DIR/future_not_send.rs:26:1
  |
 LL | pub async fn public_future2(rc: Rc<[u8]>) {}
- |  ^ future returned by `public_future2` is not `Send`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ future returned by `public_future2` is not `Send`
  |
 note: captured value is not `Send`
  --> $DIR/future_not_send.rs:26:29
@@ -71,10 +71,10 @@ LL | pub async fn public_future2(rc: Rc<[u8]>) {}
  = note: `std::rc::Rc<[u8]>` doesn't implement `std::marker::Send`
 
 error: future cannot be sent between threads safely
- --> $DIR/future_not_send.rs:38:39
+ --> $DIR/future_not_send.rs:38:5
  |
 LL | async fn private_future(&self) -> usize {
- |  ^^^^^ future returned by `private_future` is not `Send`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ future returned by `private_future` is not `Send`
  |
 note: future is not `Send` as this value is used across an await
  --> $DIR/future_not_send.rs:40:24
@@ -87,10 +87,10 @@ LL | async { true }.await;
  = note: `std::rc::Rc<[u8]>` doesn't implement `std::marker::Sync`
 
 error: future cannot be sent between threads safely
- --> $DIR/future_not_send.rs:44:39
+ --> $DIR/future_not_send.rs:44:5
  |
 LL | pub async fn public_future(&self) {
- |  ^ future returned by `public_future` is not `Send`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ future returned by `public_future` is not `Send`
  |
 note: captured value is not `Send` because `&` references cannot be sent unless their referent is `Sync`
  --> $DIR/future_not_send.rs:44:32
@@ -100,10 +100,13 @@ LL | pub async fn public_future(&self) {
  = note: `std::rc::Rc<[u8]>` doesn't implement `std::marker::Sync`
 
 error: future cannot be sent between threads safely
- --> $DIR/future_not_send.rs:55:37
+ --> $DIR/future_not_send.rs:55:1
  |
-LL | async fn generic_future<T>(t: T) -> T
- | ^ future returned by `generic_future` is not `Send`
+LL | / async fn generic_future<T>(t: T) -> T
+LL | |
+LL | | where
+LL | | T: Send,
+ | |____________^ future returned by `generic_future` is not `Send`
  |
 note: future is not `Send` as this value is used across an await
  --> $DIR/future_not_send.rs:61:20
@@ -115,10 +118,10 @@ LL | async { true }.await;
  = note: `T` doesn't implement `std::marker::Sync`
 
 error: future cannot be sent between threads safely
- --> $DIR/future_not_send.rs:73:34
+ --> $DIR/future_not_send.rs:73:1
  |
 LL | async fn unclear_future<T>(t: T) {}
- |  ^ future returned by `unclear_future` is not `Send`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ future returned by `unclear_future` is not `Send`
  |
 note: captured value is not `Send`
  --> $DIR/future_not_send.rs:73:28

tests/ui/async-await/async-await-let-else.stderr

@@ -22,7 +22,7 @@ error[E0277]: `Rc<()>` cannot be sent between threads safely
  --> $DIR/async-await-let-else.rs:47:13
  |
 LL | async fn foo2(x: Option<bool>) {
- |  - within this `impl Future<Output = ()>`
+ | ------------------------------ within this `impl Future<Output = ()>`
 ...
 LL | is_send(foo2(Some(true)));
  | ------- ^^^^^^^^^^^^^^^^ `Rc<()>` cannot be sent between threads safely

tests/ui/async-await/in-trait/async-example-desugared-boxed-in-trait.stderr

@@ -1,8 +1,8 @@
 error[E0053]: method `foo` has an incompatible type for trait
- --> $DIR/async-example-desugared-boxed-in-trait.rs:15:28
+ --> $DIR/async-example-desugared-boxed-in-trait.rs:15:5
  |
 LL | async fn foo(&self) -> i32 {
- |  ^^^ expected `Pin<Box<dyn Future<Output = i32>>>`, found future
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `Pin<Box<dyn Future<Output = i32>>>`, found future
  |
 note: type in trait
  --> $DIR/async-example-desugared-boxed-in-trait.rs:11:22

tests/ui/async-await/in-trait/async-generics-and-bounds.stderr

@@ -1,36 +1,36 @@
 error[E0311]: the parameter type `U` may not live long enough
- --> $DIR/async-generics-and-bounds.rs:12:28
+ --> $DIR/async-generics-and-bounds.rs:12:5
  |
 LL | async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
- |  ^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
 note: the parameter type `U` must be valid for the anonymous lifetime as defined here...
  --> $DIR/async-generics-and-bounds.rs:12:18
  |
 LL | async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
  | ^
 note: ...so that the reference type `&(T, U)` does not outlive the data it points at
- --> $DIR/async-generics-and-bounds.rs:12:28
+ --> $DIR/async-generics-and-bounds.rs:12:5
  |
 LL | async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
- |  ^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0311]: the parameter type `T` may not live long enough
- --> $DIR/async-generics-and-bounds.rs:12:28
+ --> $DIR/async-generics-and-bounds.rs:12:5
  |
 LL | async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
- |  ^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
 note: the parameter type `T` must be valid for the anonymous lifetime as defined here...
  --> $DIR/async-generics-and-bounds.rs:12:18
  |
 LL | async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
  | ^
 note: ...so that the reference type `&(T, U)` does not outlive the data it points at
- --> $DIR/async-generics-and-bounds.rs:12:28
+ --> $DIR/async-generics-and-bounds.rs:12:5
  |
 LL | async fn foo(&self) -> &(T, U) where T: Debug + Sized, U: Hash;
- |  ^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

tests/ui/async-await/in-trait/async-generics.stderr

@@ -1,36 +1,36 @@
 error[E0311]: the parameter type `U` may not live long enough
- --> $DIR/async-generics.rs:9:28
+ --> $DIR/async-generics.rs:9:5
  |
 LL | async fn foo(&self) -> &(T, U);
- |  ^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
 note: the parameter type `U` must be valid for the anonymous lifetime as defined here...
  --> $DIR/async-generics.rs:9:18
  |
 LL | async fn foo(&self) -> &(T, U);
  | ^
 note: ...so that the reference type `&(T, U)` does not outlive the data it points at
- --> $DIR/async-generics.rs:9:28
+ --> $DIR/async-generics.rs:9:5
  |
 LL | async fn foo(&self) -> &(T, U);
- |  ^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0311]: the parameter type `T` may not live long enough
- --> $DIR/async-generics.rs:9:28
+ --> $DIR/async-generics.rs:9:5
  |
 LL | async fn foo(&self) -> &(T, U);
- |  ^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
 note: the parameter type `T` must be valid for the anonymous lifetime as defined here...
  --> $DIR/async-generics.rs:9:18
  |
 LL | async fn foo(&self) -> &(T, U);
  | ^
 note: ...so that the reference type `&(T, U)` does not outlive the data it points at
- --> $DIR/async-generics.rs:9:28
+ --> $DIR/async-generics.rs:9:5
  |
 LL | async fn foo(&self) -> &(T, U);
- |  ^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

tests/ui/async-await/in-trait/async-recursive-generic.stderr

@@ -1,8 +1,8 @@
 error[E0733]: recursion in an `async fn` requires boxing
- --> $DIR/async-recursive-generic.rs:11:48
+ --> $DIR/async-recursive-generic.rs:11:5
  |
 LL | async fn foo_recursive(&self, n: usize) -> T {
- |  ^ recursive `async fn`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ recursive `async fn`
  |
  = note: a recursive `async fn` must be rewritten to return a boxed `dyn Future`
  = note: consider using the `async_recursion` crate: https://crates.io/crates/async_recursion

tests/ui/async-await/in-trait/async-recursive.stderr

@@ -1,8 +1,8 @@
 error[E0733]: recursion in an `async fn` requires boxing
- --> $DIR/async-recursive.rs:11:48
+ --> $DIR/async-recursive.rs:11:5
  |
 LL | async fn foo_recursive(&self, n: usize) -> i32 {
- |  ^^^ recursive `async fn`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ recursive `async fn`
  |
  = note: a recursive `async fn` must be rewritten to return a boxed `dyn Future`
  = note: consider using the `async_recursion` crate: https://crates.io/crates/async_recursion

tests/ui/async-await/in-trait/dont-project-to-specializable-projection.stderr

@@ -1,14 +1,14 @@
 error[E0053]: method `foo` has an incompatible type for trait
- --> $DIR/dont-project-to-specializable-projection.rs:14:35
+ --> $DIR/dont-project-to-specializable-projection.rs:14:5
  |
 LL | default async fn foo(_: T) -> &'static str {
- |  ^^^^^^^^^^^^ expected associated type, found future
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected associated type, found future
  |
 note: type in trait
- --> $DIR/dont-project-to-specializable-projection.rs:10:27
+ --> $DIR/dont-project-to-specializable-projection.rs:10:5
  |
 LL | async fn foo(_: T) -> &'static str;
- |  ^^^^^^^^^^^^
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  = note: expected signature `fn(_) -> impl Future<Output = &'static str>`
  found signature `fn(_) -> impl Future<Output = &'static str>`
 

tests/ui/async-await/issue-64130-3-other.stderr

@@ -2,7 +2,7 @@ error[E0277]: the trait bound `Foo: Qux` is not satisfied in `impl Future<Output
  --> $DIR/issue-64130-3-other.rs:25:12
  |
 LL | async fn bar() {
- |  - within this `impl Future<Output = ()>`
+ | -------------- within this `impl Future<Output = ()>`
 ...
 LL | is_qux(bar());
  | ^^^^^ within `impl Future<Output = ()>`, the trait `Qux` is not implemented for `Foo`

tests/ui/async-await/issues/issue-67893.stderr

@@ -6,10 +6,10 @@ LL | g(issue_67893::run())
  | |
  | required by a bound introduced by this call
  |
- ::: $DIR/auxiliary/issue_67893.rs:9:20
+ ::: $DIR/auxiliary/issue_67893.rs:9:1
  |
 LL | pub async fn run() {
- |  - within this `impl Future<Output = ()>`
+ | ------------------ within this `impl Future<Output = ()>`
  |
  = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `MutexGuard<'_, ()>`
  = note: required because it captures the following types: `Arc<Mutex<()>>`, `MutexGuard<'_, ()>`, `impl Future<Output = ()>`

tests/ui/async-await/mutually-recursive-async-impl-trait-type.stderr

@@ -1,17 +1,17 @@
 error[E0733]: recursion in an `async fn` requires boxing
- --> $DIR/mutually-recursive-async-impl-trait-type.rs:5:18
+ --> $DIR/mutually-recursive-async-impl-trait-type.rs:5:1
  |
 LL | async fn rec_1() {
- |  ^ recursive `async fn`
+ | ^^^^^^^^^^^^^^^^ recursive `async fn`
  |
  = note: a recursive `async fn` must be rewritten to return a boxed `dyn Future`
  = note: consider using the `async_recursion` crate: https://crates.io/crates/async_recursion
 
 error[E0733]: recursion in an `async fn` requires boxing
- --> $DIR/mutually-recursive-async-impl-trait-type.rs:9:18
+ --> $DIR/mutually-recursive-async-impl-trait-type.rs:9:1
  |
 LL | async fn rec_2() {
- |  ^ recursive `async fn`
+ | ^^^^^^^^^^^^^^^^ recursive `async fn`
  |
  = note: a recursive `async fn` must be rewritten to return a boxed `dyn Future`
  = note: consider using the `async_recursion` crate: https://crates.io/crates/async_recursion

tests/ui/async-await/partial-drop-partial-reinit.stderr

@@ -7,7 +7,7 @@ LL | gimme_send(foo());
  | required by a bound introduced by this call
 ...
 LL | async fn foo() {
- |  - within this `impl Future<Output = ()>`
+ | -------------- within this `impl Future<Output = ()>`
  |
  = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `NotSend`
  = note: required because it appears within the type `(NotSend,)`

tests/ui/async-await/recursive-async-impl-trait-type.stderr

@@ -1,8 +1,8 @@
 error[E0733]: recursion in an `async fn` requires boxing
- --> $DIR/recursive-async-impl-trait-type.rs:5:40
+ --> $DIR/recursive-async-impl-trait-type.rs:5:1
  |
 LL | async fn recursive_async_function() -> () {
- |  ^^ recursive `async fn`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ recursive `async fn`
  |
  = note: a recursive `async fn` must be rewritten to return a boxed `dyn Future`
  = note: consider using the `async_recursion` crate: https://crates.io/crates/async_recursion

tests/ui/suggestions/impl-trait-missing-lifetime.stderr

@@ -26,9 +26,9 @@ error: lifetime may not live long enough
  --> $DIR/impl-trait-missing-lifetime.rs:16:69
  |
 LL | async fn i(mut x: impl Iterator<Item = &'_ ()>) -> Option<&'_ ()> { x.next() }
- |  -------------- ^^^^^^^^ returning this value requires that `'1` must outlive `'static`
- |  |
- |  return type `impl Future<Output = Option<&'static ()>>` contains a lifetime `'1`
+ | ----------------------------------------------------------------- ^^^^^^^^ returning this value requires that `'1` must outlive `'static`
+ | |
+ | return type `impl Future<Output = Option<&'static ()>>` contains a lifetime `'1`
 
 error: aborting due to 3 previous errors
 

tests/ui/suggestions/suggest-ret-on-async-w-late.stderr

@@ -2,7 +2,7 @@ error[E0308]: mismatched types
  --> $DIR/suggest-ret-on-async-w-late.rs:7:5
  |
 LL | async fn ice(_: &i32) {
- |  - help: try adding a return type: `-> bool`
+ | --------------------- help: try adding a return type: `-> bool`
 LL | true
  | ^^^^ expected `()`, found `bool`
 

tests/ui/typeck/issue-90027-async-fn-return-suggestion.stderr

@@ -2,15 +2,15 @@ error[E0308]: mismatched types
  --> $DIR/issue-90027-async-fn-return-suggestion.rs:4:5
  |
 LL | async fn hello() {
- |  - help: try adding a return type: `-> i32`
+ | ---------------- help: try adding a return type: `-> i32`
 LL | 0
  | ^ expected `()`, found integer
 
 error[E0308]: mismatched types
  --> $DIR/issue-90027-async-fn-return-suggestion.rs:9:5
  |
 LL | async fn world() -> () {
- |  -- expected `()` because of return type
+ | ---------------------- expected `()` because of return type
 LL | 0
  | ^ expected `()`, found integer