Updated based on comments

src/Features/Core/Portable/CodeLens/CodeLensFindReferenceProgress.cs

@@ -78,21 +78,14 @@ private static bool FilterDefinition(ISymbol definition)
                    (definition as IMethodSymbol)?.AssociatedSymbol != null;
         }
 
-        /// <summary>
-        /// Returns partial symbol locations whose node does not match the queried syntaxNode
-        /// </summary>
-        /// <param name="symbol">Symbol whose locations are queried</param>
-        /// <param name="cancellationToken">Cancellation token</param>
-        /// <returns>Partial locations</returns>
+        // Returns partial symbol locations whose node does not match the queried syntaxNode
         private IEnumerable<Location> GetPartialLocations(ISymbol symbol, CancellationToken cancellationToken)
         {
             // Returns nodes from source not equal to actual location
             return from syntaxReference in symbol.DeclaringSyntaxReferences
-                let candidateSyntaxNode = syntaxReference.GetSyntax(cancellationToken)
-                where !(_queriedNode.Span == candidateSyntaxNode.Span &&
-                        _queriedNode.SyntaxTree.FilePath.Equals(candidateSyntaxNode.SyntaxTree.FilePath,
-                            StringComparison.OrdinalIgnoreCase))
-                select syntaxReference.SyntaxTree.GetLocation(syntaxReference.Span);
+                   let candidateSyntaxNode = syntaxReference.GetSyntax(cancellationToken)
+                   where _queriedNode != candidateSyntaxNode
+                   select candidateSyntaxNode.GetLocation();
         }
 
         public void OnDefinitionFound(ISymbol symbol)

src/Features/Core/Portable/CodeLens/CodeLensReferenceService.cs

@@ -33,10 +33,6 @@ internal sealed class CodeLensReferenceService : ICodeLensReferencesService
             }
 
             var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
-            if (semanticModel == null)
-            {
-                return null;
-            }
 
             cancellationToken.ThrowIfCancellationRequested();
 
@@ -92,10 +88,6 @@ private static async Task<ReferenceLocationDescriptor> GetDescriptorOfEnclosingS
             }
 
             var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
-            if (semanticModel == null)
-            {
-                return null;
-            }
 
             var langServices = document.GetLanguageService<ICodeLensDisplayInfoService>();
             if (langServices == null)
@@ -231,11 +223,6 @@ private static async Task<ReferenceMethodDescriptor> GetMethodDescriptorAsync(Lo
 
             var document = solution.GetDocument(doc.Id);
             var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
-            if (semanticModel == null)
-            {
-                return null;
-            }
-
             var fullName = GetEnclosingMethod(semanticModel, commonLocation)?.ToDisplayString(MethodDisplayFormat);
 
             return !string.IsNullOrEmpty(fullName) ? new ReferenceMethodDescriptor(fullName, document.FilePath) : null;
@@ -269,10 +256,6 @@ public async Task<IEnumerable<ReferenceMethodDescriptor>> FindReferenceMethodsAs
 
             var document = solution.GetDocument(doc.Id);
             var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
-            if (semanticModel == null)
-            {
-                return null;
-            }
 
             return GetEnclosingMethod(semanticModel, commonLocation)?.ToDisplayString(MethodDisplayFormat);
         }