LanguageFeatures/Constructor-tear-offs/function_tearoffs_A02_t01.dart

// Copyright (c) 2021, 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 These grammar changes allows type parameters without following
/// parenthesized arguments in places where we previously did not allow them.
/// For example, this means that <typeArguments> becomes a selector by itself,
/// not just followed by arguments.
///
/// It applies to instance methods as well as local, static and top-level
/// function declarations. For instance methods, it applies to references of the
/// form
///
/// instanceMethod<int> (with implicit this),
/// object.instanceMethod<int> (including this) and super.instanceMethod<int>.
///
/// @description Checks tear-off of generic instance method
/// @author sgrekhov@unipro.ru

// SharedOptions=--enable-experiment=constructor-tearoffs

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

class C {
  var x;
  C() {
    var x = instanceMethod<int>;
    Expect.equals(42, x(42));
    dynamic d1 = -42;
    Expect.isTrue(x(d1) is int);
    Expect.isFalse(x(d1) is String); // to check that returned type is not dynamic
    Expect.runtimeIsType<int>(x(d1));
    Expect.runtimeIsNotType<String>(x(d1));
    dynamic d2 = 3.14;
    Expect.throws(() {x(d2);});
  }
  T instanceMethod<T>(T t) => t;
}

main() {
  new C();
}