Compile time error on forward references to functions

tests/language/ref_before_declaration_test.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.
 
 // Test compile-time errors for illegal variable declarations if the name
 // has been referenced before the variable is declared.
 
 import 'dart:math' as math;
 
 use(value) => value;
@@ skipping 23 matching lines @@
 
   void test3() {
     if (true) {
       use(x);  // Refers to top-level x.
       use(y);  // Refers to top-level y.
     }
     final x = "I have not yet begun to procrastinate.";  /// 02: compile-time error
     const y = "Honk if you like peace and quiet!";  /// 03: compile-time error
   }
 
+  void test4() {
+    void Q() {
+      P();  // Refers to non-existing top-level function P
+    }
+    void P() {  /// 06: compile-time error
+      Q();      /// 06: continued
+    }           /// 06: continued
+  }
+
   test() {
     test1();
     test2();
     test3();
+    test4();
   }
 }
 
 void testTypeRef() {
   String s = 'Can vegetarians eat animal crackers?';
   var String = "I distinctly remember forgetting that.";  /// 04: compile-time error
 }
 
 void testLibPrefix() {
   var pie = math.PI;
@@ skipping 14 matching lines @@
   var int = 007;
 }
 
 void main() {
   var c = new C();
   c.test();
   testTypeRef();
   testLibPrefix();
   noErrorsExpected();
 }