From 94d15ebbef906c282bff145b442cb4834739017f Mon Sep 17 00:00:00 2001
From: Michele Caini <michele.caini@gmail.com>
Date: Fri, 28 Feb 2020 15:23:44 +0100
Subject: [PATCH] config: being empty isn't enough for ETO, type must be
 default constructible

---
 src/entt/config/config.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/entt/config/config.h b/src/entt/config/config.h
index 90f39fd90..2b97320f9 100644
--- a/src/entt/config/config.h
+++ b/src/entt/config/config.h
@@ -44,10 +44,10 @@
 
 #ifndef ENTT_DISABLE_ETO
 #   include <type_traits>
-#   define ENTT_ENABLE_ETO(Type) std::is_empty_v<Type>
+#   define ENTT_ENABLE_ETO(Type) (std::is_default_constructible_v<Type> && std::is_empty_v<Type>)
 #else
 #   // sfinae-friendly definition
-#   define ENTT_ENABLE_ETO(Type) (false && std::is_empty_v<Type>)
+#   define ENTT_ENABLE_ETO(Type) (false && std::is_void_v<Type>)
 #endif