diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 421633f..c479895 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -2417,8 +2417,7 @@
     return TDK_SubstitutionFailure;
 
   if (FunctionType) {
-    *FunctionType = BuildFunctionType(ResultType,
-                                      ParamTypes.data(), ParamTypes.size(),
+    *FunctionType = BuildFunctionType(ResultType, ParamTypes,
                                       Proto->isVariadic(),
                                       Proto->hasTrailingReturn(),
                                       Proto->getTypeQuals(),