error[E0637]: `'_` cannot be used here
  --> $DIR/issue-95305.rs:11:26
   |
LL | fn foo(x: &impl Foo<Item<'_> = u32>) { }
   |                          ^^ `'_` is a reserved lifetime name

error[E0106]: missing lifetime specifier
  --> $DIR/issue-95305.rs:14:41
   |
LL | fn bar(x: &impl for<'a> Foo<Item<'a> = &'_ u32>) { }
   |                                         ^^ expected named lifetime parameter
   |
help: consider using the `'a` lifetime
   |
LL | fn bar(x: &impl for<'a> Foo<Item<'a> = &'a u32>) { }
   |                                         ~~

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0106, E0637.
For more information about an error, try `rustc --explain E0106`.