diff --git a/libcxx/include/__functional_base b/libcxx/include/__functional_base
--- a/libcxx/include/__functional_base
+++ b/libcxx/include/__functional_base
@@ -665,6 +665,18 @@
 
 #endif  // _LIBCPP_CXX03_LANG
 
+#if _LIBCPP_STD_VER > 14
+
+template <class _Fn, class ..._Args>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 invoke_result_t<_Fn, _Args...>
+invoke(_Fn&& __f, _Args&&... __args)
+    noexcept(is_nothrow_invocable_v<_Fn, _Args...>)
+{
+    return _VSTD::__invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
+}
+
+#endif // _LIBCPP_STD_VER > 14
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // _LIBCPP_FUNCTIONAL_BASE
diff --git a/libcxx/include/concepts b/libcxx/include/concepts
--- a/libcxx/include/concepts
+++ b/libcxx/include/concepts
@@ -135,7 +135,7 @@
 */
 
 #include <__config>
-#include <functional>
+#include <__functional_base>
 #include <type_traits>
 #include <utility>
 #include <version>
diff --git a/libcxx/include/functional b/libcxx/include/functional
--- a/libcxx/include/functional
+++ b/libcxx/include/functional
@@ -2984,14 +2984,6 @@
 
 #if _LIBCPP_STD_VER > 14
 
-template <class _Fn, class ..._Args>
-_LIBCPP_CONSTEXPR_AFTER_CXX17 invoke_result_t<_Fn, _Args...>
-invoke(_Fn&& __f, _Args&&... __args)
-    noexcept(is_nothrow_invocable_v<_Fn, _Args...>)
-{
-    return _VSTD::__invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
-}
-
 template<class _Op, class _Tuple,
          class _Idxs = typename __make_tuple_indices<tuple_size<_Tuple>::value>::type>
 struct __perfect_forward_impl;