error[E0404]: expected trait, found type parameter `Read`
  --> $DIR/issue-120559.rs:3:9
   |
LL | use std::io::Read;
   |              ---- you might have meant to refer to this trait
LL |
LL | fn f<T: Read, U, Read>() {}
   |         ^^^^     ---- found this type parameter
   |         |
   |         not a trait

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0404`.