error[E0308]: mismatched types
  --> $DIR/issue-50716.rs:14:9
   |
LL |     let _x = *s;
   |         ^^ lifetime mismatch
   |
   = note: expected type `Sized`
              found type `Sized`
note: the lifetime `'a` as defined on the function body at 9:8...
  --> $DIR/issue-50716.rs:9:8
   |
LL | fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
   |        ^^
   = note: ...does not necessarily outlive the static lifetime

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.