error[E0792]: expected generic lifetime parameter, found `'_`
  --> $DIR/issue-109054.rs:18:9
   |
LL | type ReturnType<'a> = impl std::future::Future<Output = u32> + 'a;
   |                 -- this generic parameter must be used with a generic lifetime parameter
...
LL |         &inner
   |         ^^^^^^

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0792`.