error[E0403]: the name `T` is already used for a type parameter in this type parameter list
  --> $DIR/E0403.rs:11:11
   |
LL | fn foo<T, T>(s: T, u: T) {} //~ ERROR E0403
   |        -  ^ already used
   |        |
   |        first use of `T`

error: aborting due to previous error

If you want more information on this error, try using "rustc --explain E0403"