diff --git a/lib/Sema/IdentifierResolver.cpp b/lib/Sema/IdentifierResolver.cpp
index 8375720..82f95bf 100644
--- a/lib/Sema/IdentifierResolver.cpp
+++ b/lib/Sema/IdentifierResolver.cpp
@@ -243,7 +243,7 @@
 /// declaration context 'Ctx'. If 'LookInParentCtx' is true, it will walk the
 /// decls of parent declaration contexts too.
 IdentifierResolver::iterator
-IdentifierResolver::begin(const IdentifierInfo *II, DeclContext *Ctx,
+IdentifierResolver::begin(const IdentifierInfo *II, const DeclContext *Ctx,
                           bool LookInParentCtx) {
   assert(Ctx && "null param passed");