diff --git a/expected.hpp b/expected.hpp
index 5f930c3..c9fe9a6 100644
--- a/expected.hpp
+++ b/expected.hpp
@@ -1700,7 +1700,7 @@ template <class Exp, class F,
           class Ret = decltype(detail::invoke(std::declval<F>(),
                                               *std::declval<Exp>())),
           detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
-constexpr auto map_error_impl(Exp &&exp, F &&f) {
+auto map_error_impl(Exp &&exp, F &&f) {
   using result = expected<exp_t<Exp>, monostate>;
   if (exp.has_value()) {
       return result(*std::forward<Exp>(exp));
@@ -1728,7 +1728,7 @@ template <class Exp, class F,
           class Ret = decltype(detail::invoke(std::declval<F>(),
                                               *std::declval<Exp>())),
           detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
-constexpr auto map_error_impl(Exp &&exp, F &&f) -> expected<exp_t<Exp>, monostate> {
+auto map_error_impl(Exp &&exp, F &&f) -> expected<exp_t<Exp>, monostate> {
   using result = expected<exp_t<Exp>, monostate>;
   if (exp.has_value()) {
       return result(*std::forward<Exp>(exp));