Index: include/pstl/internal/glue_numeric_defs.h
===================================================================
--- include/pstl/internal/glue_numeric_defs.h
+++ include/pstl/internal/glue_numeric_defs.h
@@ -57,7 +57,7 @@
                _ForwardIterator2 __result, _Tp __init);
 
 template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation>
-_ForwardIterator2
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
 exclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
                _ForwardIterator2 __result, _Tp __init, _BinaryOperation __binary_op);
 
Index: include/pstl/internal/glue_numeric_impl.h
===================================================================
--- include/pstl/internal/glue_numeric_impl.h
+++ include/pstl/internal/glue_numeric_impl.h
@@ -101,7 +101,7 @@
 }
 
 template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation>
-_ForwardIterator2
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
 exclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
                _ForwardIterator2 __result, _Tp __init, _BinaryOperation __binary_op)
 {