diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 9901080..49e3639 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -7838,6 +7838,8 @@
   case TSK_ImplicitInstantiation:
     return GVA_TemplateInstantiation;
   }
+
+  llvm_unreachable("Invalid Linkage!");
 }
 
 bool ASTContext::DeclMustBeEmitted(const Decl *D) {