error: expected identifier, found `<`
  --> $DIR/existing_generics.rs:5:3
   |
LL | fn<'a, B: 'a + std::ops::Add<Output = u32>> f<T>(_x: B) { }
   |   ^ expected identifier
   |
   = help: place the generic parameter name after the fn name

error: aborting due to previous error