SIL verification failed: convert_function cannot change function ABI
  different number of parameters
  @callee_owned (@in (Int, Float)) -> ()
  @callee_owned (Int, Float) -> ()

class C<T> {
 func f(t: T) {
   print(t)
 }
}

class B : C<(Int, Float)> {
 override func f(t: (Int, Float)) {
   print(t)
 }
}

let fn1: (C<(Int, Float)>) -> ((Int, Float)) -> () = C.f
let fn2: (B) -> ((Int, Float)) -> () = B.f

fn1(B())((100, 200.0))
fn2(B())((100, 200.0))