diff --git a/src/Features/Core/Portable/AddParameter/AbstractAddParameterCodeFixProvider.cs b/src/Features/Core/Portable/AddParameter/AbstractAddParameterCodeFixProvider.cs
index 16b7bdf64d937772b75bda5c8ec81ec24e391cb6..01d0bf410c146c3f5563f05fbceb1366adbaf55a 100644
--- a/src/Features/Core/Portable/AddParameter/AbstractAddParameterCodeFixProvider.cs
+++ b/src/Features/Core/Portable/AddParameter/AbstractAddParameterCodeFixProvider.cs
@@ -304,7 +304,11 @@ private int NonParamsParameterCount(IMethodSymbol method)
 
                     var parameterDeclaration = generator.ParameterDeclaration(parameterSymbol)
                                                         .WithAdditionalAnnotations(Formatter.Annotation);
-
+                    if (anySymbolReferencesNotInSource && methodDeclaration == method)
+                    {
+                        parameterDeclaration = parameterDeclaration.WithAdditionalAnnotations(
+                            ConflictAnnotation.Create("One or more method declarations that needed to be updated are not available as source code."));
+                    }
                     var existingParameters = generator.GetParameters(methodNode);
                     var insertionIndex = isNamedArgument
                         ? existingParameters.Count