Issue 21419. Don't create navigation region for elements without location.

pkg/analysis_server/test/analysis/notification_navigation_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.
 
 library test.analysis.notification.navigation;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/protocol.dart';
@@ skipping 351 matching lines @@
         findRegion(findOffset('new '), 'new'.length, true);
         assertHasTarget('A() {}', 0);
       }
       {
         findRegion(findOffset('A();'), 'A'.length, true);
         assertHasTarget('A {');
       }
     });
   }
 
+  test_multiplyDefinedElement() {
+    addFile('$projectPath/bin/libA.dart', 'library A; int TEST = 1;');
+    addFile('$projectPath/bin/libB.dart', 'library B; int TEST = 2;');
+    addTestFile('''
+import 'libA.dart';
+import 'libB.dart';
+main() {
+  TEST;
+}
+''');
+    return prepareNavigation().then((_) {
+      assertNoRegionAt('TEST');
+    });
+  }
+
   test_operator_arithmetic() {
     addTestFile('''
 class A {
   A operator +(other) => null;
   A operator -() => null;
   A operator -(other) => null;
   A operator *(other) => null;
   A operator /(other) => null;
 }
 main() {
@@ skipping 155 matching lines @@
   test_type_void() {
     addTestFile('''
 void main() {
 }
 ''');
     return prepareNavigation().then((_) {
       assertNoRegionAt('void');
     });
   }
 }