Language/15_Types/4_Interface_Types_A12_t19.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 type T is more specific than a type S, written T << S, if one of the following conditions is met:
 *   - T is S.
 *   - T is ⊥
 *   - S is Dynamic.
 *   - S is a direct supertype of T.
 *   - T is a type variable and S is the upper bound of T.
 *   - T is of the form I<T1, ..., Tn > and S is of the form I <S1, ..., Sn> and Ti << Si 1 <= i <= n.
 *   - T and S are both function types, and T << S under the rules of section (Types/Function Types).
 *   - T is a function type and S is Function.
 *   - T << U and U << S.
 * T is a subtype of S, written T <: S, iff [⊥/Dynamic]T << S.
 * A type T may be assigned to a type S, written T <=> S, if either T <: S or S <: T .
 * @description Checks that if T is function type and S is Function then the interface type T <<
 * the interface type Function.
 * @static-clean
 * @author ilya
 */
import "../../Utils/expect.dart";

int f(String s) => 1;

main() {
  Expect.isTrue(f is Function);
  Expect.isTrue((int x, String s) {} is Function);
}