error[E0308]: mismatched types
  --> $DIR/issue-32323.rs:5:30
   |
LL | pub fn f<'a, T: Tr<'a>>() -> <T as Tr<'a>>::Out {}
   |        -                     ^^^^^^^^^^^^^^^^^^ expected associated type, found ()
   |        |
   |        implicitly returns `()` as its body has no tail or `return` expression
   |
   = note: expected associated type `<T as Tr<'a>>::Out`
                    found unit type `()`
   = note: consider constraining the associated type `<T as Tr<'a>>::Out` to `()` or calling a method that returns `<T as Tr<'a>>::Out`
   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html

error: aborting due to previous error

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