test/SILGen/call_as_function.swift

// RUN: %target-swift-emit-silgen %s | %FileCheck %s

struct S {
  func callAsFunction(_ x: Int) -> Int! { nil }
}

protocol P1 {
  func callAsFunction()
}

protocol P2 {
  func callAsFunction() -> Self
}

class C {
  func callAsFunction(_ x: String) -> Self { return self }
}

// CHECK-LABEL: sil hidden [ossa] @$s16call_as_function05test_a1_b1_C0yyAA1SV_AA2P1_pAA2P2_pxtAA1CCRbzlF : $@convention(thin) <T where T : C> (S, @in_guaranteed P1, @in_guaranteed P2, @guaranteed T) -> ()
func test_call_as_function<T : C>(_ s: S, _ p1: P1, _ p2: P2, _ t: T) {
  // CHECK: function_ref @$s16call_as_function1SV0A10AsFunctionySiSgSiF : $@convention(method) (Int, S) -> Optional<Int>
  // CHECK: switch_enum %{{.+}} : $Optional<Int>
  let _: Int = s(0)

  // SR-12590: SILGen crash on existential callAsFunction.
  // CHECK: witness_method $@opened({{.+}}) P1, #P1.callAsFunction : <Self where Self : P1> (Self) -> () -> ()
  p1()

  // CHECK: witness_method $@opened({{.+}}) P2, #P2.callAsFunction : <Self where Self : P2> (Self) -> () -> Self
  _ = p2()

  // CHECK: class_method %{{.+}} : $C, #C.callAsFunction : (C) -> (String) -> @dynamic_self C, $@convention(method) (@guaranteed String, @guaranteed C) -> @owned C
  // CHECK: unchecked_ref_cast %{{.+}} : $C to $T
  _ = t("")
}