diff --git a/lib/AST/CommentSema.cpp b/lib/AST/CommentSema.cpp
index fa8001b..72b0af3 100644
--- a/lib/AST/CommentSema.cpp
+++ b/lib/AST/CommentSema.cpp
@@ -384,7 +384,7 @@
                                     const ParmVarDecl * const *ParamVars,
                                     unsigned NumParams) {
   const unsigned MaxEditDistance = (Typo.size() + 2) / 3;
-  unsigned BestPVDIndex = NULL;
+  unsigned BestPVDIndex = 0;
   unsigned BestEditDistance = MaxEditDistance + 1;
   for (unsigned i = 0; i != NumParams; ++i) {
     const IdentifierInfo *II = ParamVars[i]->getIdentifier();