From 1b72597be02fd79354f8238acb40fe778ca4c891 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Tue, 24 Mar 2026 17:47:52 -0400
Subject: [PATCH] xo-facet: bugfix: is_convertible_v usage

is_convertible_v<T,T> can be false if T isn't copyable.
since dealing with a T pointer, actually want
is_convertible_v<T*,T*>
---
 include/xo/facet/OObject.hpp              | 4 ++--
 include/xo/facet/facet_implementation.hpp | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/xo/facet/OObject.hpp b/include/xo/facet/OObject.hpp
index 24397e5..3968286 100644
--- a/include/xo/facet/OObject.hpp
+++ b/include/xo/facet/OObject.hpp
@@ -180,7 +180,7 @@ namespace xo {
                      * Either way need to force vtable replacement, hence memcpy here
                      */
                     _launder_from(oother);
-                } else if constexpr (std::is_convertible_v<DRepr, DOther>) {
+                } else if constexpr (std::is_convertible_v<DRepr*, DOther*>) {
                     /* other is typed, consistently with *this */
                     this->from_data(oother.data());
                 } else
@@ -189,7 +189,7 @@ namespace xo {
                     //  + may fail at runtime
 
                     static_assert(std::is_same_v<DRepr, DVariantPlaceholder>
-                                  || std::is_convertible_v<DRepr, DOther>);
+                                  || std::is_convertible_v<DRepr*, DOther*>);
                 }
                 return *this;
             }
diff --git a/include/xo/facet/facet_implementation.hpp b/include/xo/facet/facet_implementation.hpp
index 7ce2ed5..d8a78f6 100644
--- a/include/xo/facet/facet_implementation.hpp
+++ b/include/xo/facet/facet_implementation.hpp
@@ -102,7 +102,7 @@ namespace xo {
 
         /** Retrieve facet implementation for a (facet,datatype) pair **/
         template <typename AFacet, typename DRepr>
-        using FacetImplType = FacetImplementation<AFacet, DRepr>::ImplType;
+        using FacetImplType = typename FacetImplementation<AFacet, DRepr>::ImplType;
 
         /** Use:
          *    auto iface = xo::facet::impl_for<AGCObject, DList>();