From 3f0aad9f746381e71aab75d126ce9b3ac0a0b6cb Mon Sep 17 00:00:00 2001
From: Alexander Karatarakis <alex@karatarakis.com>
Date: Thu, 3 Oct 2019 00:02:39 -0700
Subject: [PATCH] Fix regression of enum_cast<>() when used with refs (EnumT&
 vs EnumT) (#16)

---
 include/magic_enum.hpp | 2 +-
 test/test.cpp          | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/magic_enum.hpp b/include/magic_enum.hpp
index 6280aa6..edf73c1 100644
--- a/include/magic_enum.hpp
+++ b/include/magic_enum.hpp
@@ -437,7 +437,7 @@ template <typename E>
 // Obtains enum value from integer value.
 // Returns std::optional with enum value.
 template <typename E>
-[[nodiscard]] constexpr auto enum_cast(std::underlying_type_t<E> value) noexcept -> detail::enable_if_enum_t<E, std::optional<std::decay_t<E>>> {
+[[nodiscard]] constexpr auto enum_cast(std::underlying_type_t<std::decay_t<E>> value) noexcept -> detail::enable_if_enum_t<std::decay_t<E>, std::optional<std::decay_t<E>>> {
   using D = std::decay_t<E>;
 
   if (enum_traits<D>::index(static_cast<D>(value)) != -1) {
diff --git a/test/test.cpp b/test/test.cpp
index 1b8631b..49ce5dc 100644
--- a/test/test.cpp
+++ b/test/test.cpp
@@ -86,6 +86,7 @@ TEST_CASE("enum_cast") {
     constexpr auto cr = enum_cast<Color>(-12);
     REQUIRE(cr.value() == Color::RED);
     REQUIRE(enum_cast<Color>(7).value() == Color::GREEN);
+    REQUIRE(enum_cast<Color&>(7).value() == Color::GREEN);
     REQUIRE(enum_cast<Color>((int)cm[2]).value() == Color::BLUE);
     REQUIRE_FALSE(enum_cast<Color>(0).has_value());