error[E0277]: the trait bound `[static generator@$DIR/async.rs:7:29: 9:2]: Generator<ResumeTy>` is not satisfied
  --> $DIR/async.rs:7:29
   |
LL |   async fn foo(x: u32) -> u32 {
   |  _____________________________^
LL | |     x
LL | | }
   | |_^ the trait `Generator<ResumeTy>` is not implemented for `[static generator@$DIR/async.rs:7:29: 9:2]`
   |
note: required by a bound in `std::future::from_generator`
  --> $SRC_DIR/core/src/future/mod.rs:LL:COL
   |
LL |     T: Generator<ResumeTy, Yield = ()>,
   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `std::future::from_generator`

error[E0280]: the requirement `<[static generator@$DIR/async.rs:7:29: 9:2] as Generator<ResumeTy>>::Yield == ()` is not satisfied
  --> $DIR/async.rs:7:29
   |
LL |   async fn foo(x: u32) -> u32 {
   |  _____________________________^
LL | |     x
LL | | }
   | |_^
   |
note: required by a bound in `std::future::from_generator`
  --> $SRC_DIR/core/src/future/mod.rs:LL:COL
   |
LL |     T: Generator<ResumeTy, Yield = ()>,
   |                            ^^^^^^^^^^ required by this bound in `std::future::from_generator`

error[E0280]: the requirement `<impl Future<Output = u32> as Future>::Output == u32` is not satisfied
  --> $DIR/async.rs:7:25
   |
LL | async fn foo(x: u32) -> u32 {
   |                         ^^^

error: aborting due to 3 previous errors

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