diff --git a/clang/include/clang/Sema/SemaInternal.h b/clang/include/clang/Sema/SemaInternal.h
index 27cda71989726..95874077050a9 100644
--- a/clang/include/clang/Sema/SemaInternal.h
+++ b/clang/include/clang/Sema/SemaInternal.h
@@ -72,7 +72,7 @@ inline std::pair<unsigned, unsigned> getDepthAndIndex(const NamedDecl *ND) {
 /// Retrieve the depth and index of an unexpanded parameter pack.
 inline std::pair<unsigned, unsigned>
 getDepthAndIndex(UnexpandedParameterPack UPP) {
-  if (const auto *TTP = UPP.first.dyn_cast<const TemplateTypeParmType *>())
+  if (const auto *TTP = dyn_cast<const TemplateTypeParmType *>(UPP.first))
     return std::make_pair(TTP->getDepth(), TTP->getIndex());
 
   return getDepthAndIndex(cast<NamedDecl *>(UPP.first));