error[E0369]: binary operation `==` cannot be applied to type `S<T>`
  --> $DIR/invalid-bin-op.rs:2:15
   |
LL |     let _ = s == t;
   |             - ^^ - S<T>
   |             |
   |             S<T>
   |
note: an implementation of `PartialEq<_>` might be missing for `S<T>`
  --> $DIR/invalid-bin-op.rs:5:1
   |
LL | struct S<T>(T);
   | ^^^^^^^^^^^ must implement `PartialEq<_>`
help: consider annotating `S<T>` with `#[derive(PartialEq)]`
   |
LL + #[derive(PartialEq)]
LL | struct S<T>(T);
   |
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
   |
LL | pub fn foo<T>(s: S<T>, t: S<T>) where S<T>: PartialEq {
   |                                 +++++++++++++++++++++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0369`.