Language/15_Types/5_Function_Types_A03_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. For all i 1 <= i <= n, Ti <=> Si.
 * 3. k >= m and yi belongs to {x1, ..., xk} for each i in 1..m.
 * 4. For all y in {y1, ..., ym}, yi = xj  =>  Tj <=> Si
 * @description Checks that function type t1 is still a subtype of function type t2 if their named
 * named optional parameters have identical names and mutually assignale types, regardless of the order
 * they're declared in.
 * @author rodionov
 * @reviewer kaigorodov
 */
import "../../Utils/expect.dart";

typedef t1({int x, double d, String s});

main() {
  Expect.isTrue(({int x, String s, double d}) {} is t1);
  Expect.isTrue(({double d, int x, String s}) {} is t1);
  Expect.isTrue(({double d, String s, int x}) {} is t1);
  Expect.isTrue(({String s, double d, int x}) {} is t1);
  Expect.isTrue(({String s, int x, double d}) {} is t1);
}