Language/07_Classes/6_Constructors/3_Constant_Constructors_A05_t02.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 When invoked from a constant object expression, a constant constructor
 * must throw an exception if any of its actual parameters is a value that would
 * prevent one of the potentially constant expressions within it from being a valid
 * compile-time constant.
 * @description Checks that compile-time error is produced if actual parameters passed to the constructor
 * make the constant initializer invalid. Note: this mechanism is described in Classes.Constructors.Constant_Constructors.
 * @compile-error
 * @author iefremov
 * @reviewer rodionov
 */

class A {
  final x;
  const A(var p) : x = p + 42;
}

class IntPair {
  const IntPair(this.x, this.y);
  final int x;
  final int y;
  operator +(v) => new IntPair(x+v, y+v);
}


main() {
  try {
    var a = const A(const IntPair(1,2)); // parameter does not evaluate to int/bool/String, despite implementing the plus operator
  } catch (x){}
}