Language/15_Types/4_Interface_Types_A10_t06.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 T is of the form I<T1, ..., Tn> and
 * S is of the form I<S1, ..., Sn> and: Ti << Si , 1 <= i <= n
 * << is a partial order on types. 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 GenericType<T> is a subtype of GenericType<S> where T and S are trivial generics.
 * @author iefremov
 * @reviewer rodionov
 */
import "../../Utils/expect.dart";

class I {}
class J extends I {}
class K extends J {}
class L extends K {}

// subtypes of each other, according to (Types/Function Types)
typedef J f(List<num> l, [J i]);
typedef I f_1(List<int> l, [I i]);
typedef K f_2(List<int> l, [L i]);

main() {
  Expect.isTrue(new List<List>() is List);
  Expect.isTrue(new List<List>() is List<List<List>>);
  Expect.isTrue(new List<List>() is List<List<List<List>>>);
  Expect.isTrue(new List<List<List<List>>>() is List<List<List>>);
  Expect.isTrue(new List<List<List<List>>>() is List);

  Expect.isTrue(new List<Map<int, double>>() is List<Map>);
  Expect.isTrue(new List<Map<int, double>>() is List<Map<num, num>>);

  Expect.isTrue(new List<f>() is List<f>);
  Expect.isTrue(new List<f_1>() is List<f>);
  Expect.isTrue(new List<f_2>() is List<f>);
}