Migrate language block 46 - canonical_const ... char_escape.

tests/language_strong/cascade_test.dart

-// Copyright (c) 2012, 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.
-
-import "package:expect/expect.dart";
-
-// Test cascades.
-
-class A {
-  int x;
-  int y;
-
-  A(this.x, this.y);
-
-  A setX(int x) {
-    this.x = x;
-    return this;
-  }
-
-  void setY(int y) {
-    this.y = y;
-  }
-
-  Function swap() {
-    int tmp = x;
-    x = y;
-    y = tmp;
-    return this.swap;
-  }
-
-  void check(int x, int y) {
-    Expect.equals(x, this.x);
-    Expect.equals(y, this.y);
-  }
-
-  operator [](var i) {
-    if (i == 0) return x;
-    if (i == 1) return y;
-    if (i == "swap") return this.swap;
-    return null;
-  }
-
-  int operator []=(int i, int value) {
-    if (i == 0) {
-      x = value;
-    } else if (i == 1) {
-      y = value;
-    }
-  }
-
-  /**
-   * A pseudo-keyword.
-   */
-  import() {
-    x++;
-  }
-}
-
-main() {
-  A a = new A(1, 2);
-  a
-    ..check(1, 2)
-    ..swap()
-    ..check(2, 1)
-    ..x = 4
-    ..y = 9
-    ..check(4, 9)
-    ..setX(10)
-    ..check(10, 9)
-    ..y = 5
-    ..check(10, 5)
-    ..swap()()()
-    ..check(5, 10)
-    ..[0] = 2
-    ..check(2, 10)
-    ..setX(10).setY(3)
-    ..check(10, 3)
-    ..setX(7)["swap"]()
-    ..check(3, 7)
-    ..import()
-    ..check(4, 7)
-    ..["swap"]()()()
-    ..check(7, 4);
-  a.check(7, 4);
-  a..(42); // //# 01: compile-time error
-  a..37; // //# 02: compile-time error
-  a.."foo"; // //# 03: compile-time error
-}