More dead code removal (using -Wunreachable-code)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148577 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseExprCXX.cpp b/lib/Parse/ParseExprCXX.cpp
index 4bd4c6f..8046f6b 100644
--- a/lib/Parse/ParseExprCXX.cpp
+++ b/lib/Parse/ParseExprCXX.cpp
@@ -2464,7 +2464,7 @@
                                        T.getCloseLocation());
   }
   }
-  return ExprError();
+  llvm_unreachable("Invalid ArrayTypeTrait!");
 }
 
 /// ParseExpressionTrait - Parse built-in expression-trait