diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index 56cd4dd..f1b6470 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -965,6 +965,7 @@
 
 const char *BuiltinType::getName(const LangOptions &LO) const {
   switch (getKind()) {
+  default: assert(0 && "Invalid builtin type!");
   case Void:              return "void";
   case Bool:              return LO.Bool ? "bool" : "_Bool";
   case Char_S:            return "char";