Language/Types/Function_Types/subtype_named_args_t09.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 even if just one of its required parameters has a type that is not
 * mutually assignable with the type of the corresponding required parameter of
 * t2.
 * @author rodionov
 */
import "../../../Utils/expect.dart";

class B {}

typedef B func(Object o);
typedef B t1(int i, B b, Map<int, num> m, var x, {var ox, B? ob, List<num>? ol, bool? obool});

B f1(double i, B b, Map<int, num> m, var x, {var ox, B? ob, List<num>? ol, bool? obool}) => new B();
//    ^^^ double <=/=> int
B f2(int i, func b, Map<int, num> m, var x, {var ox, B? ob, List<num>? ol, bool? obool}) => new B();
//          ^^^ func <=/=> B
B f3(int i, B b, Map<int, func> m, var x, {var ox, B? ob, List<num>? ol, bool? obool}) => new B();
//                       ^^^ func <=/=> num

main() {
  Expect.isFalse(f1 is t1);
  Expect.isFalse(f2 is t1);
  Expect.isFalse(f3 is t1);
}