Merge pull request #2977 from pharring/Port2966

Port2966

src/EditorFeatures/Test2/FindReferences/FindReferencesTests.NamedTypeSymbols.vb

@@ -2156,5 +2156,34 @@ public class D { }
 
             Test(input)
         End Sub
+
+        <Fact, Trait(Traits.Feature, Traits.Features.FindReferences)>
+        <WorkItem(1174256)>
+        Public Sub TestFarWithInternalsVisibleToNull()
+            Dim input =
+<Workspace>
+    <Project Language="C#" AssemblyName="ClassLibrary1" CommonReferences="true">
+        <Document><![CDATA[
+        [assembly: System.Runtime.CompilerServices.InternalsVisibleTo(null)]
+        internal class {|Definition:$$A|}
+        {
+        }]]>
+        </Document>
+    </Project>
+
+    <Project Language="C#" AssemblyName="ClassLibrary2" CommonReferences="true">
+        <ProjectReference>ClassLibrary1</ProjectReference>
+        <Document><![CDATA[
+        public class B : A
+        {
+        }]]>
+        </Document>
+    </Project>
+</Workspace>
+
+            Test(input)
+
+        End Sub
+
     End Class
 End Namespace

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

@@ -364,6 +364,11 @@ private static Lazy<HashSet<string>> CreateInternalsVisibleToMap(IAssemblySymbol
                     }
 
                     var value = (string)typeNameConstant.Value;
+                    if (value == null)
+                    {
+                        continue;
+                    }
+
                     var commaIndex = value.IndexOf(',');
                     var assemblyName = commaIndex >= 0 ? value.Substring(0, commaIndex).Trim() : value;