1 files changed, 4 insertions, 0 deletions
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 1fd616a086..e304f54226 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -1455,6 +1455,10 @@ TemplateSpecializationType::PrintTemplateArgumentList(
     // Print the argument into a string.
     std::string ArgString;
     switch (Args[Arg].getKind()) {
+    case TemplateArgument::Null:
+      assert(false && "Null template argument");
+      break;
+
     case TemplateArgument::Type:
       Args[Arg].getAsType().getAsStringInternal(ArgString, Policy);
       break;