From 929c197fff9fe99dde6323e701b14b83bb5c4862 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Johel=20Ernesto=20Guerrero=20Pe=C3=B1a?=
 <johelegp@gmail.com>
Date: Thu, 25 Feb 2021 17:43:17 -0400
Subject: [PATCH] fix: downcasting facility for GCC 11

---
 src/include/units/bits/external/downcasting.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/include/units/bits/external/downcasting.h b/src/include/units/bits/external/downcasting.h
index adfefddf..16749fbf 100644
--- a/src/include/units/bits/external/downcasting.h
+++ b/src/include/units/bits/external/downcasting.h
@@ -86,7 +86,7 @@ namespace detail {
 template<typename T>
 constexpr auto downcast_impl()
 {
-  if constexpr(has_downcast_guide<T> && !has_downcast_poison_pill<T>)
+  if constexpr(has_downcast_guide<downcast_base<T>> && !has_downcast_poison_pill<downcast_base<T>>)
     return decltype(downcast_guide(std::declval<downcast_base<T>>()))();
   else
     return std::type_identity<T>();