Report only private members in the same library as overrides.

pkg/analysis_server/lib/src/services/search/search_engine_internal.dart

Index: pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
diff --git a/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart b/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
index b551b48123e7d993ff0966d38af10892d910a65b..8e1519ed165766b5da734bac396ce0646b1567f1 100644
--- a/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
+++ b/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
@@ -23,6 +23,7 @@ class SearchEngineImpl implements SearchEngine {
   Future<Set<String>> membersOfSubtypes(ClassElement type) async {
     List<AnalysisDriver> drivers = _drivers.toList();
 
+    String libraryUriStr = type.librarySource.uri.toString();
     bool hasSubtypes = false;
     Set<String> visitedIds = new Set<String>();
     Set<String> members = new Set<String>();
@@ -34,9 +35,11 @@ class SearchEngineImpl implements SearchEngine {
       for (AnalysisDriver driver in drivers) {
         List<SubtypeResult> subtypes =
             await driver.search.subtypes(type: type, subtype: subtype);
-        for (var subtype in subtypes) {
+        for (SubtypeResult subtype in subtypes) {
           hasSubtypes = true;
-          members.addAll(subtype.members);
+          members.addAll(subtype.libraryUri == libraryUriStr
+              ? subtype.members
+              : subtype.members.where((name) => !name.startsWith('_')));
           await addMembers(null, subtype);
         }
       }