Language/Types/Function_Types/subtype_required_args_t04.dart

// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// @assertion A function type (T1,...Tk,[Tk+1,...,Tn+m]) -> T is a subtype of
/// the function type (S1,...,Sk+j,[Sk+j+1,...,Sn]) -> S, if all of the following
/// conditions are met:
/// 1. Either
///    • S is void, or
///    • T <=> S.
/// 2. ∀i ∈ 1..n, Ti ⇐⇒ Si.
/// @description Checks that function type t1 is not a subtype of function type
/// t2 if a formal parameter of t1 is not assignable to a corresponding parameter
/// of t2 (both t1 and t2 have a single required formal parameter).
/// @author iefremov

import "../../../Utils/expect.dart";

class A {}
class B {}

typedef t1(int a);
typedef t3(A a);
typedef t4(List<A> a);
typedef t5(t1 a);

main() {
  Expect.isFalse((double p) {} is t1);
  Expect.isFalse((bool p) {} is t1);
  Expect.isFalse((A p) {} is t1);
  Expect.isFalse((List<int> p) {} is t1);
  Expect.isFalse((t3 p) {} is t1);

  Expect.isFalse((double p) {} is t3);
  Expect.isFalse((bool p) {} is t3);
  Expect.isFalse((List<int> p) {} is t3);
  Expect.isFalse((t3 p) {} is t3);
  Expect.isFalse((B p) {} is t3);

  Expect.isFalse((double p) {} is t4);
  Expect.isFalse((bool p) {} is t4);
  Expect.isFalse((A p) {} is t4);
  Expect.isFalse((List<int> p) {} is t4);
  Expect.isFalse((List<B> p) {} is t4);
  Expect.isFalse((t3 p) {} is t4);

  Expect.isFalse((double p) {} is t5);
  Expect.isFalse((bool p) {} is t5);
  Expect.isFalse((A p) {} is t5);
  Expect.isFalse((List<int> p) {} is t5);
  Expect.isFalse((t4 p) {} is t5);
}