Add an assert() suggested by Richard.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184516 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index f91182b..70c933e 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -858,6 +858,7 @@
 }
 
 TypeDecl *ASTContext::getFloat128StubType() const {
+  assert(LangOpts.CPlusPlus && "should only be called for c++");
   if (!Float128StubDecl) {
     Float128StubDecl = CXXRecordDecl::Create(const_cast<ASTContext &>(*this), 
                                              TTK_Struct,