Allow closures in string literals in initializer expressions.

tests/language/parse_closures_in_initializers_test.dart

+// Copyright (c) 2014, 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 that function literals are parsed correctly in initializers.
+
+class A {
+  final x;
+  static foo(f) => f();
+
+  A.parenthesized(y) : x = (() => y);
+  A.stringLiteral(y) : x = "**${() => y}--";
+  A.listLiteral(y) : x = [() => y];
+  A.mapLiteral(y) : x = { "fun": () => y };
+  A.arg(y) : x = foo(() => y);
+}
+
+main() {
+  var a, f;
+  a = new A.parenthesized(499);
+  f = a.x;
+  Expect.isTrue(f is Function);
+  Expect.equals(499, f());
+
+  // The toString of closures is not specified. Just make sure that there is no
+  // crash.
+  a = new A.stringLiteral(42);
+  Expect.isTrue(a.x.startsWith("**"));
+  Expect.isTrue(a.x.endsWith("--"));
+
+  a = new A.listLiteral(99);
+  f = a.x[0];
+  Expect.isTrue(f is Function);
+  Expect.equals(99, f());
+
+  a = new A.mapLiteral(314);
+  f = a.x["fun"];
+  Expect.isTrue(f is Function);
+  Expect.equals(314, f());
+
+  a = new A.arg(123);
+  Expect.equals(123, a.x);
+}