From 2aebb8e187fbb516c11631c9eec9737c6f1c6740 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Fri, 27 Mar 2026 22:33:21 -0400
Subject: [PATCH] xo-gc stack: genfacet for Collector + facet registry bugfix

---
 include/xo/gc/PolyForwarderUtil.hpp | 8 ++++++--
 src/gc/DX1Collector.cpp             | 2 +-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/include/xo/gc/PolyForwarderUtil.hpp b/include/xo/gc/PolyForwarderUtil.hpp
index 19f99c9..6d87159 100644
--- a/include/xo/gc/PolyForwarderUtil.hpp
+++ b/include/xo/gc/PolyForwarderUtil.hpp
@@ -51,8 +51,12 @@ namespace xo {
                  *                   +-------+
                  **/
 
-                auto gco = FacetRegistry::instance().variant<AGCObject,AFacet>(*p_ptr);
-                gc.forward_inplace(gco.iface(), (void **)&(p_ptr->data_));
+                if (*p_ptr) {
+                    auto gco = FacetRegistry::instance().variant<AGCObject,AFacet>(*p_ptr);
+                    gc.forward_inplace(gco.iface(), (void **)&(p_ptr->data_));
+                } else {
+                    // nullptr is trivial to forward
+                }
             }
         };
 
diff --git a/src/gc/DX1Collector.cpp b/src/gc/DX1Collector.cpp
index cd6ba5d..b3b9c8d 100644
--- a/src/gc/DX1Collector.cpp
+++ b/src/gc/DX1Collector.cpp
@@ -179,7 +179,7 @@ namespace xo {
                 }
             }
 
-            for (uint32_t j = 1; j < config_.n_generation_; ++j) {
+            for (uint32_t j = 0; j + 1 < config_.n_generation_; ++j) {
                 for (uint32_t i = 0; i < c_n_role + 1; ++i) {
                     mlog_storage_[i][j].visit_pools(visitor);
                 }