Language/Expressions/Type_Test/definition_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 Let v be a local variable or a formal parameter. An is-expression
/// of the form v is T shows that v has type T iff T is more specific than the
/// type S of the expression v and both T != dynamic and S != dynamic.
/// @description Checks that if T is less specific than S, then is-expression
/// does not show that v has type T.
/// @author ilya

class C {}
class D extends C { f() {} }

f(D x) {
  D y = x;

  x is C ? x.f() : null; // formal parameter
  y is C ? y.f() : null; // local variable
}

main() {
  f(new D());
}