diff --git a/include/string_view b/include/string_view
index e8584a6..4df4f02 100644
--- a/include/string_view
+++ b/include/string_view
@@ -306,6 +306,8 @@ public:
 
   _LIBCPP_HIDE_FROM_ABI basic_string_view& operator=(const basic_string_view&) _NOEXCEPT = default;
 
+  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view(nullptr_t, size_t) = delete;
+
   _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT
       : __data_(__s),
         __size_(__len) {
@@ -344,7 +346,7 @@ public:
   _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view(const _CharT* __s)
       : __data_(__s), __size_(std::__char_traits_length_checked<_Traits>(__s)) {}
 
-#if _LIBCPP_STD_VER >= 23
+#if _LIBCPP_STD_VER >= 20
   basic_string_view(nullptr_t) = delete;
 #endif
 
@@ -666,7 +668,7 @@ public:
   }
 #endif
 
-#if _LIBCPP_STD_VER >= 23
+#if _LIBCPP_STD_VER >= 20
   constexpr _LIBCPP_HIDE_FROM_ABI bool contains(basic_string_view __sv) const noexcept { return find(__sv) != npos; }
 
   constexpr _LIBCPP_HIDE_FROM_ABI bool contains(value_type __c) const noexcept { return find(__c) != npos; }