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:7:12
   |
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

error[E0277]: `impl Future<Output = ()> { <_ as Foo>::bar() }` cannot be sent between threads safely
  --> $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
   |     |
   |     required by a bound introduced by this call
   |
   = 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:22:11
   |
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:19:39
   |
LL | fn build<T>(_: T) where T: Foo<bar(): Send> {}
   |                                       ^^^^ required by this bound in `build`

error: aborting due to 1 previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0277`.