diff --git a/include/xo/gc/X1Collector.hpp b/include/xo/gc/X1Collector.hpp
index 3899984..c35f525 100644
--- a/include/xo/gc/X1Collector.hpp
+++ b/include/xo/gc/X1Collector.hpp
@@ -8,5 +8,6 @@
 #include "DX1Collector.hpp"
 #include "detail/ICollector_DX1Collector.hpp"
 #include "detail/IAllocator_DX1Collector.hpp"
+#include "detail/IGCObjectVisitor_DX1Collector.hpp"
 
 /* end X1Collector.hpp */
diff --git a/src/gc/DX1Collector.cpp b/src/gc/DX1Collector.cpp
index d31c78c..a74b7f0 100644
--- a/src/gc/DX1Collector.cpp
+++ b/src/gc/DX1Collector.cpp
@@ -13,6 +13,7 @@
 #include <xo/stringtable2/String.hpp>
 
 #include <xo/alloc2/GCObject.hpp>
+#include <xo/alloc2/GCObjectVisitor.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include <xo/alloc2/Arena.hpp>
 #include "object_age.hpp"
@@ -382,7 +383,7 @@ namespace xo {
             // Add run state so DX1Collector can recognize forward_inplace()
             // calls made for the purpose of checking child pointers.
 
-            auto self = this->ref<ACollector>();
+            auto self = this->ref<AGCObjectVisitor>();
 
             GCRunState saved_runstate = runstate_;
             {
@@ -403,7 +404,7 @@ namespace xo {
                         // - X1Collector::forward_inplace() -> _verify_aux()
                         //
 
-                        gco.forward_children(self);
+                        gco.visit_gco_children(self);
 
                     }
 
diff --git a/src/gc/GCObjectStore.cpp b/src/gc/GCObjectStore.cpp
index 4076fd9..ee900b5 100644
--- a/src/gc/GCObjectStore.cpp
+++ b/src/gc/GCObjectStore.cpp
@@ -498,7 +498,7 @@ namespace xo {
                 log && log("disposition: not in from-space. Don't forward, but check children");
 
                 obj<AGCObject> gco(lhs_iface, object_data);
-                gco.forward_children(gc->ref<ACollector>());
+                gco.visit_gco_children(gc->ref<AGCObjectVisitor>());
 
                 return;
             }
@@ -711,7 +711,7 @@ namespace xo {
                             // Nested control reenters
                             // X1Collector::forward_inplace() -> _verify_aux()
                             //
-                            gco.forward_children(gc->ref<ACollector>());
+                            gco.visit_gco_children(gc->ref<AGCObjectVisitor>());
                         } else {
                             ++(p_verify_stats->n_no_iface_);
                             continue;
@@ -771,12 +771,12 @@ namespace xo {
                 // we aren't moving from_src, it's not gc-owned.
                 // However weare moving all its gc-owned children
 
-                auto gc_obj = gc->ref<ACollector>();
+                auto gc_obj = gc->ref<AGCObjectVisitor>();
 
                 GCMoveCheckpoint gray_lo_v
                     = this->snap_move_checkpoint(upto);
 
-                from_src.forward_children(gc_obj);
+                from_src.visit_gco_children(gc_obj);
 
                 // For each generation g:
                 //   traverse objects newer than gray_lo_v[g], to make sure children
@@ -1005,9 +1005,9 @@ namespace xo {
 
                         assert(iface->_has_null_vptr() == false);
 
-                        auto gc_gco = gc->ref<ACollector>();
+                        auto gc_gco = gc->ref<AGCObjectVisitor>();
 
-                        iface->forward_children(src, gc_gco);
+                        iface->visit_gco_children(src, gc_gco);
 
                         gray_lo_v[g] = ((std::byte *)src) + z;