Language/Types/Function_Types/subtype_named_args_t05.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 The function type (T1, ... Tn, {Tx1 x1, ..., Txk xk}) -> T is a
/// subtype of the function type (S1, ..., Sn, {Sy1 y1, ..., Sym ym }) -> S, if
/// all of the following conditions are met:
/// 1. Either
///    • S is void, Or
///    • T ⇐⇒ S.
/// 2. ∀i ∈ 1..n, Ti ⇐⇒ Si .
/// 3. k ≥ m and yi ∈ {x1 , ..., xk }, i ∈ 1..m.
/// 4. For all yi ∈ {y1 , ..., ym }, yi = xj ⇒ Tj ⇐⇒ Si.
/// @description Checks that function type t1 is not a subtype of function type
/// t2 if the type of a single named optional parameter of t1 is not assignable
/// to the type of t2's single named optional parameter.
/// @author rodionov

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

class A {}
class B {}

typedef t1({int p});
typedef t2({A? p});
typedef t3({List<A> p});
typedef t4({t1? p});

main() {
  Expect.isFalse(({double p = 3.14}) {} is t1);
  Expect.isFalse(({bool p = false}) {} is t1);
  Expect.isFalse(({A? p}) {} is t1);
  Expect.isFalse(({List<int> p = const [3, 1, 4]}) {} is t1);
  Expect.isFalse(({t2? p}) {} is t1);

  Expect.isFalse(({double p = 3.14}) {} is t2);
  Expect.isFalse(({bool p = false}) {} is t2);
  Expect.isFalse(({List<int> p = const [3, 1, 4]}) {} is t2);
  Expect.isFalse(({t2? p}) {} is t2);
  Expect.isFalse(({B? p}) {} is t2);

  Expect.isFalse(({double p = 3.14}) {} is t3);
  Expect.isFalse(({bool p = false}) {} is t3);
  Expect.isFalse(({A? p}) {} is t3);
  Expect.isFalse(({List<int> p = const <int>[]}) {} is t3);
  Expect.isFalse(({List<B>? p}) {} is t3);
  Expect.isFalse(({t2? p}) {} is t3);

  Expect.isFalse(({double p = 42}) {} is t4);
  Expect.isFalse(({bool p = true}) {} is t4);
  Expect.isFalse(({A? p}) {} is t4);
  Expect.isFalse(({List<int> p = const []}) {} is t4);
  Expect.isFalse(({t2? p}) {} is t4);
  Expect.isFalse(({t3? p}) {} is t4);
  Expect.isFalse(({t4? p}) {} is t4);
}