LanguageFeatures/Extension-methods/tearoffs_t01.dart

// Copyright (c) 2019, 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 static extension method can be torn off like an instance method.
///
/// @description Check that a static extension method can be torn off like an
/// instance method.
/// @author sgrekhov@unipro.ru


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

class C {
  Object val;
  C(this.val);

  String toString() => val.toString();
}

extension ExtendedList on List {
  int foo<T extends C>(T x) => x.toString().length;
}

main() {
  List list = [1, 2, 3];
  int Function(C) func = list.foo;
  Expect.equals(3, func(C([1])));
  Expect.equals(3, func(C("[1]")));
  Expect.equals(13, func(C("Lily was here")));
}