Trim common path elements for C#/VB find references, just like we do for TypeScript.

src/VisualStudio/Core/Def/Implementation/Library/FindResults/LibraryManager_FindReferences.cs

@@ -21,12 +21,19 @@ public void PresentReferencedSymbols(string title, Solution solution, IEnumerabl
         }
 
         // internal for test purposes
-        internal IList<AbstractTreeItem> CreateFindReferencesItems(Solution solution, IEnumerable<ReferencedSymbol> referencedSymbols)
+        internal IList<AbstractTreeItem> CreateFindReferencesItems(
+            Solution solution, IEnumerable<ReferencedSymbol> referencedSymbols)
         {
             var definitions = new List<AbstractTreeItem>();
             var uniqueLocations = new HashSet<ValueTuple<Document, TextSpan>>();
             var symbolNavigationService = solution.Workspace.Services.GetService<ISymbolNavigationService>();
 
+            var documents = referencedSymbols.SelectMany(s => s.Locations)
+                                             .Select(loc => loc.Document)
+                                             .WhereNotNull()
+                                             .ToSet();
+            var commonPathElements = CountCommonPathElements(documents);
+
             referencedSymbols = referencedSymbols.FilterToItemsToShow().ToList();
 
             foreach (var referencedSymbol in referencedSymbols.OrderBy(GetDefinitionPrecedence))
@@ -56,7 +63,10 @@ internal IList<AbstractTreeItem> CreateFindReferencesItems(Solution solution, IE
                     {
                         definitions.Add(definitionItem);
 
-                        var referenceItems = CreateReferenceItems(solution, uniqueLocations, referencedSymbol.Locations.Select(loc => loc.Location));
+                        var referenceItems = CreateReferenceItems(
+                            solution, uniqueLocations,
+                            referencedSymbol.Locations.Select(loc => loc.Location),
+                            commonPathElements);
                         definitionItem.Children.AddRange(referenceItems);
                         definitionItem.SetReferenceCount(referenceItems.Count);
                     }
@@ -136,7 +146,11 @@ private int GetDefinitionPrecedence(ReferencedSymbol referencedSymbol)
             return new SourceDefinitionTreeItem(document, sourceSpan, referencedSymbol.Definition, glyph.GetGlyphIndex());
         }
 
-        private IList<SourceReferenceTreeItem> CreateReferenceItems(Solution solution, HashSet<ValueTuple<Document, TextSpan>> uniqueLocations, IEnumerable<Location> locations)
+        private IList<SourceReferenceTreeItem> CreateReferenceItems(
+            Solution solution,
+            HashSet<ValueTuple<Document, TextSpan>> uniqueLocations,
+            IEnumerable<Location> locations,
+            int commonPathElements)
         {
             var referenceItems = new List<SourceReferenceTreeItem>();
             foreach (var location in locations)
@@ -155,7 +169,8 @@ private IList<SourceReferenceTreeItem> CreateReferenceItems(Solution solution, H
 
                 if (uniqueLocations.Add(new ValueTuple<Document, TextSpan>(document, sourceSpan)))
                 {
-                    referenceItems.Add(new SourceReferenceTreeItem(document, sourceSpan, Glyph.Reference.GetGlyphIndex()));
+                    referenceItems.Add(new SourceReferenceTreeItem(
+                        document, sourceSpan, Glyph.Reference.GetGlyphIndex(), commonPathElements));
                 }
             }
 

src/VisualStudio/Core/Def/Implementation/Library/FindResults/LibraryManager_GoToDefinition.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
@@ -32,10 +31,15 @@ private IList<AbstractTreeItem> CreateNavigableItemTreeItems(IEnumerable<INaviga
             return CreateNavigableItemTreeItems(itemsList, commonPathElements);
         }
 
-        private int CountCommonPathElements(HashSet<Document> documents)
+        private int CountCommonPathElements(ISet<Document> documents)
         {
-            Debug.Assert(documents.Count > 0);
+            if (documents.Count == 0)
+            {
+                return 0;
+            }
+
             var commonPathElements = 0;
+
             for (var index = 0; ; index++)
             {
                 var pathPortion = GetPathPortion(documents.First(), index);

src/VisualStudio/Core/Def/Implementation/Library/FindResults/TreeItems/SourceReferenceTreeItem.cs

@@ -9,7 +9,9 @@ namespace Microsoft.VisualStudio.LanguageServices.Implementation.Library.FindRes
 {
     internal class SourceReferenceTreeItem : AbstractSourceTreeItem, IComparable<SourceReferenceTreeItem>
     {
-        public SourceReferenceTreeItem(Document document, TextSpan sourceSpan, ushort glyphIndex, int commonPathElements = 0, string displayText = null, bool includeFileLocation = false)
+        public SourceReferenceTreeItem(
+            Document document, TextSpan sourceSpan, ushort glyphIndex, int commonPathElements,
+            string displayText = null, bool includeFileLocation = false)
             : base(document, sourceSpan, glyphIndex, commonPathElements)
         {
             if (displayText != null && !includeFileLocation)