start partitioning the diagnostics into two classes: those
that are builtin and those that are aren't.  This is a bunch
of API refactoring that will make this possible, but there is
no functionality change yet.

llvm-svn: 44473
diff --git a/clang/Driver/RewriteTest.cpp b/clang/Driver/RewriteTest.cpp
index 5d14f03..808fe98 100644
--- a/clang/Driver/RewriteTest.cpp
+++ b/clang/Driver/RewriteTest.cpp
@@ -17,6 +17,7 @@
 #include "clang/AST/ASTConsumer.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/IdentifierTable.h"
+#include "clang/Basic/Diagnostic.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "clang/Lex/Lexer.h"
@@ -869,6 +870,7 @@
     return Exp;
   }
   
+  // Replace this subexpr in the parent.
   delete Exp;
   return Replacement;
 }