diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -7517,7 +7517,7 @@
     }
   }
 
-  const FunctionProtoType *Type = MD->getType()->getAs<FunctionProtoType>();
+  const FunctionProtoType *Type = MD->getType()->castAs<FunctionProtoType>();
 
   bool CanHaveConstParam = false;
   if (CSM == CXXCopyConstructor)