error: unused implementer of `Future` that must be used
  --> $DIR/assoc-types.rs:19:5
   |
LL |     T::foo();
   |     ^^^^^^^^
   |
   = note: futures do nothing unless you `.await` or poll them
note: the lint level is defined here
  --> $DIR/assoc-types.rs:4:9
   |
LL | #![deny(unused_must_use)]
   |         ^^^^^^^^^^^^^^^

error: aborting due to 1 previous error