diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
index f16f59..9a6285 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -1334,7 +1334,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	constexpr auto
 	operator-(const __normal_iterator& __lhs,
 		  const __normal_iterator<_Iter, _Container>& __rhs) noexcept
-	-> decltype(__lhs.base() - __rhs.base())
+	-> decltype(std::declval<_Iterator>() - std::declval<_Iter>())
 #else
 	friend
 	difference_type