warning: method `dummy` is never used
  --> $DIR/where-clause-method-substituion-rpass.rs:5:19
   |
LL | trait Foo<T> { fn dummy(&self, arg: T) { } }
   |       ---         ^^^^^
   |       |
   |       method in this trait
   |
   = note: `#[warn(dead_code)]` on by default

warning: 1 warning emitted