Preliminary checked mirrors (not ready for review yet)

pkg/checked_mirrors/example/target.dart

+// Copyright (c) 2013, 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.
+
+/// Example illustrating how to use checked_mirrors, and how it works when you
+/// declare a target with [MirrorsUsed].
+library checked_mirrors.example.target;
+
+import 'package:checked_mirrors/checked_mirrors.dart';
+import 'package:checked_mirrors/control.dart' as control;
+import 'package:logging/logging.dart';
+
+// Typically this annotation goes in an import to 'dart:mirrors', we would like
+// to put it in the import of checked_mirrors, but we moved it here until
+// dartbug.com/10360 is fixed.
+@MirrorsUsed(targets: const [A])
+const checked_mirrors_workaround_for_issue_10360 = 0;
+
+class A { // this class is declared in @MirrorsUsed, so using 'x' is OK.
+  int x = 1;
+}
+
+class B { // this class is not declared, so reading 'x' will issue warnings.
+  int x = 1;
+}
+
+var a = new A();
+var b = new B();
+
+main() {
+  // This loads up the rules declared with @MirrorsUsed.
+  control.initialize(log: true);
+
+  // Print the warnings to the console.
+  Logger.root.onRecord.listen((r) => print(r));
+
+  var ax = reflect(a).getField(#x).reflectee;
+  var bx = reflect(b).getField(#x).reflectee;
+
+  reflect(a).setField(#x, ax + 1);
+  reflect(b).setField(#x, bx + 2);
+}