filter undesired suggestions from prefix expression

pkg/analysis_server/lib/src/services/completion/imported_computer.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 services.completion.computer.dart.toplevel;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart' as protocol show Element,
     ElementKind;
@@ skipping 48 matching lines @@
 
   @override
   Future<bool> visitSimpleIdentifier(SimpleIdentifier node) {
     AstNode parent = node.parent;
     if (parent is Combinator) {
       return _addCombinatorSuggestions(parent);
     }
     if (parent is ExpressionStatement) {
       return _addImportedElementSuggestions();
     }
+    if (parent is PrefixedIdentifier) {
+      if (request.offset <= parent.prefix.end) {
+        return _addImportedElementSuggestions();
+      }
+    }
     return new Future.value(false);
   }
 
   Future _addCombinatorSuggestions(Combinator node) {
     var directive = node.getAncestor((parent) => parent is NamespaceDirective);
     if (directive is NamespaceDirective) {
       LibraryElement library = directive.uriElement;
       LibraryElementSuggestionBuilder.suggestionsFor(request, library);
       return new Future.value(true);
     }
@@ skipping 105 matching lines @@
           importElem.isDeprecated,
           false);
       LibraryElement lib = importElem.importedLibrary;
       if (lib != null) {
         suggestion.element = new protocol.Element.fromEngine(lib);
       }
       request.suggestions.add(suggestion);
     }
   }
 }