error: generic arguments must come before the first constraint
  --> $DIR/issue-32214.rs:3:34
   |
LL | pub fn test<W, I: Trait<Item=(), W> >() {}
   |                         -------  ^ generic argument
   |                         |
   |                         constraint
   |
help: move the constraint after the generic argument
   |
LL | pub fn test<W, I: Trait<W, Item = ()> >() {}
   |                        ~~~~~~~~~~~~~~

error: aborting due to 1 previous error