error[E0623]: lifetime mismatch
  --> $DIR/ret-impl-trait-one.rs:12:65
   |
LL | async fn async_ret_impl_trait1<'a, 'b>(a: &'a u8, b: &'b u8) -> impl Trait<'a> {
   |                                           ------                ^^^^^^^^^^^^^^
   |                                           |                     |
   |                                           |                     ...but data from `b` is returned here
   |                                           this parameter and the return type are declared with different lifetimes...

error: aborting due to previous error

For more information about this error, try `rustc --explain E0623`.