Only distinct docs

src/Workspaces/Core/Portable/FindSymbols/FindReferences/FindReferencesSearchEngine.cs

@@ -58,9 +58,7 @@ public async Task FindReferencesAsync(ISymbol symbol)
                 var symbols = await DetermineAllSymbolsAsync(symbol).ConfigureAwait(false);
 
                 var projectMap = await CreateProjectMapAsync(symbols).ConfigureAwait(false);
-                var start = DateTime.Now;
                 var projectToDocumentMap = await CreateProjectToDocumentMapAsync(projectMap).ConfigureAwait(false);
-                Console.WriteLine("Time to make doc map: " + (DateTime.Now - start));
                 ValidateProjectToDocumentMap(projectToDocumentMap);
 
                 await ProcessAsync(projectToDocumentMap).ConfigureAwait(false);

src/Workspaces/Core/Portable/FindSymbols/FindReferences/FindReferencesSearchEngine_MapCreation.cs

@@ -63,7 +63,7 @@ private async Task<ProjectToDocumentMap> CreateProjectToDocumentMapAsync(Project
         {
             var documents = await finder.DetermineDocumentsToSearchAsync(
                 symbol, project, _documents, _options, _cancellationToken).ConfigureAwait(false);
-            var finalDocs = documents.WhereNotNull().Where(
+            var finalDocs = documents.WhereNotNull().Distinct().Where(
                 d => _documents == null || _documents.Contains(d)).ToImmutableArray();
             return (finalDocs, symbol, finder);
         }