warning: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
  --> $DIR/issue-72278.rs:14:14
   |
LL |     fn func<'a, U>(&'a self) -> U {
   |             -- the late bound lifetime parameter is introduced here
...
LL |     S.func::<'a, U>()
   |              ^^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #42868 <https://github.com/rust-lang/rust/issues/42868>
   = note: `#[warn(late_bound_lifetime_arguments)]` on by default

warning: 1 warning emitted