Issue 25538. Fix for 'analysis.implemented' notification and private members.

pkg/analysis_server/lib/src/domains/analysis/implemented_dart.dart

 // Copyright (c) 2015, 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 domains.analysis.implemented_dart;
 
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analysis_server/src/services/search/hierarchy.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 39 matching lines @@
   void _addImplementedMember(Element member) {
     int offset = member.nameOffset;
     int length = member.nameLength;
     members.add(new protocol.ImplementedMember(offset, length));
   }
 
   void _addMemberIfImplemented(Element element) {
     if (element.isSynthetic || _isStatic(element)) {
       return;
     }
-    String name = element.displayName;
-    if (name != null && _hasOverride(name)) {
+    if (_hasOverride(element)) {
       _addImplementedMember(element);
     }
   }
 
-  bool _hasOverride(String name) {
+  bool _hasOverride(Element element) {
+    String name = element.displayName;
+    LibraryElement library = element.library;
     for (ClassElement subtype in subtypes) {
-      MethodElement method = subtype.getMethod(name);
-      if (method != null) {
-        return !method.isStatic;
+      ClassMemberElement subElement = subtype.getMethod(name);
+      if (subElement == null) {
+        subElement = subtype.getField(name);
       }
-      FieldElement field = subtype.getField(name);
-      if (field != null) {
-        return !field.isStatic;
+      if (subElement != null &&
+          !subElement.isStatic &&
+          subElement.isAccessibleIn(library)) {
+        return true;
       }
     }
     return false;
   }
 
   /**
    * Return `true` if the given [element] is a static element.
    */
   static bool _isStatic(Element element) {
     if (element is ExecutableElement) {
       return element.isStatic;
     } else if (element is PropertyInducingElement) {
       return element.isStatic;
     }
     return false;
   }
 }