add an assertion for unreachable code.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67432 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclarationName.cpp b/lib/AST/DeclarationName.cpp
index 3815a08..e2ed892 100644
--- a/lib/AST/DeclarationName.cpp
+++ b/lib/AST/DeclarationName.cpp
@@ -113,6 +113,7 @@
   }
 
   // Can't actually get here.
+  assert(0 && "This should be unreachable!");
   return Identifier;
 }