entity: fix getting enum min/max

2 files changed, 20 insertions, 0 deletions

diff --git a/entity/constraints.hpp b/entity/constraints.hpp
index c807fddc..6a5587d5 100644
--- a/entity/constraints.hpp
+++ b/entity/constraints.hpp
@@ -26,6 +26,14 @@ struct limit_traits<T>
 };
 
 template<typename T>
+requires std::is_enum_v<T>
+struct limit_traits<T>
+{
+    static constexpr T min() { return T(limits<std::underlying_type_t<T>>::min); }
+    static constexpr T max() { return T(limits<std::underlying_type_t<T>>::max); }
+};
+
+template<typename T>
 struct limit_traits
 {
     static_assert(std::is_nothrow_default_constructible_v<T>);
diff --git a/test/entity.cpp b/test/entity.cpp
index 36302662..783721f1 100644
--- a/test/entity.cpp
+++ b/test/entity.cpp
@@ -281,6 +281,17 @@ void test_range4()
     fm_assert(r.second == rʹ.max);
 }
 
+constexpr bool test_enum_range()
+{
+    enum class E { foo, bar };
+    constexpr auto x = TestAccessors{};
+    constexpr auto f = entity::type<E>::field("vec"_s, constantly(E::bar), [](auto&&, auto&&) {});
+    static_assert(f.read(x) == E::bar);
+    constexpr auto r = f.get_range(x);
+    static_assert(r.max != E{0});
+    return true;
+}
+
 } // namespace
 
 void test_app::test_entity()
@@ -300,6 +311,7 @@ void test_app::test_entity()
     test_range2();
     static_assert(test_range3());
     test_range4();
+    static_assert(test_enum_range());
 }
 
 } // namespace floormat