error[E0658]: `impl Trait` in type aliases is unstable
  --> $DIR/issue-60371.rs:8:17
   |
LL |     type Item = impl Bug;
   |                 ^^^^^^^^
   |
   = note: see issue #63063 <https://github.com/rust-lang/rust/issues/63063> for more information
   = help: add `#![feature(type_alias_impl_trait)]` to the crate attributes to enable

error[E0277]: the trait bound `(): Bug` is not satisfied
  --> $DIR/issue-60371.rs:10:40
   |
LL |     const FUN: fn() -> Self::Item = || ();
   |                                        ^ the trait `Bug` is not implemented for `()`
   |
   = help: the trait `Bug` is implemented for `&()`

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0277, E0658.
For more information about an error, try `rustc --explain E0277`.