diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index ab400cd..e04d72d 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -5193,6 +5193,7 @@
   case InitializedEntity::EK_ComplexElement:
     llvm_unreachable("should not materialize a temporary to initialize this");
   }
+  llvm_unreachable("unknown entity kind");
 }
 
 static void performLifetimeExtension(Expr *Init, const ValueDecl *ExtendingD);