diff --git a/include/xo/object2/array/IGCObject_DArray.hpp b/include/xo/object2/array/IGCObject_DArray.hpp
index 4cd5f02..31ab574 100644
--- a/include/xo/object2/array/IGCObject_DArray.hpp
+++ b/include/xo/object2/array/IGCObject_DArray.hpp
@@ -41,7 +41,6 @@ namespace xo {
             ///@{
             using size_type = xo::mm::AGCObject::size_type;
             using AAllocator = xo::mm::AGCObject::AAllocator;
-            using ACollector = xo::mm::AGCObject::ACollector;
             using AGCObjectVisitor = xo::mm::AGCObject::AGCObjectVisitor;
             using VisitReason = xo::mm::AGCObject::VisitReason;
             using Copaque = xo::mm::AGCObject::Copaque;
diff --git a/include/xo/object2/boolean/IGCObject_DBoolean.hpp b/include/xo/object2/boolean/IGCObject_DBoolean.hpp
index 8ab00b0..a3cff7c 100644
--- a/include/xo/object2/boolean/IGCObject_DBoolean.hpp
+++ b/include/xo/object2/boolean/IGCObject_DBoolean.hpp
@@ -41,7 +41,6 @@ namespace xo {
             ///@{
             using size_type = xo::mm::AGCObject::size_type;
             using AAllocator = xo::mm::AGCObject::AAllocator;
-            using ACollector = xo::mm::AGCObject::ACollector;
             using AGCObjectVisitor = xo::mm::AGCObject::AGCObjectVisitor;
             using VisitReason = xo::mm::AGCObject::VisitReason;
             using Copaque = xo::mm::AGCObject::Copaque;
diff --git a/include/xo/object2/dictionary/IGCObject_DDictionary.hpp b/include/xo/object2/dictionary/IGCObject_DDictionary.hpp
index 52d093b..acaffdf 100644
--- a/include/xo/object2/dictionary/IGCObject_DDictionary.hpp
+++ b/include/xo/object2/dictionary/IGCObject_DDictionary.hpp
@@ -41,7 +41,6 @@ namespace xo {
             ///@{
             using size_type = xo::mm::AGCObject::size_type;
             using AAllocator = xo::mm::AGCObject::AAllocator;
-            using ACollector = xo::mm::AGCObject::ACollector;
             using AGCObjectVisitor = xo::mm::AGCObject::AGCObjectVisitor;
             using VisitReason = xo::mm::AGCObject::VisitReason;
             using Copaque = xo::mm::AGCObject::Copaque;
diff --git a/include/xo/object2/error/IGCObject_DRuntimeError.hpp b/include/xo/object2/error/IGCObject_DRuntimeError.hpp
index 19e378b..7f31367 100644
--- a/include/xo/object2/error/IGCObject_DRuntimeError.hpp
+++ b/include/xo/object2/error/IGCObject_DRuntimeError.hpp
@@ -41,7 +41,6 @@ namespace xo {
             ///@{
             using size_type = xo::mm::AGCObject::size_type;
             using AAllocator = xo::mm::AGCObject::AAllocator;
-            using ACollector = xo::mm::AGCObject::ACollector;
             using AGCObjectVisitor = xo::mm::AGCObject::AGCObjectVisitor;
             using VisitReason = xo::mm::AGCObject::VisitReason;
             using Copaque = xo::mm::AGCObject::Copaque;
diff --git a/include/xo/object2/list/IGCObject_DList.hpp b/include/xo/object2/list/IGCObject_DList.hpp
index 10463fe..94de87d 100644
--- a/include/xo/object2/list/IGCObject_DList.hpp
+++ b/include/xo/object2/list/IGCObject_DList.hpp
@@ -41,7 +41,6 @@ namespace xo {
             ///@{
             using size_type = xo::mm::AGCObject::size_type;
             using AAllocator = xo::mm::AGCObject::AAllocator;
-            using ACollector = xo::mm::AGCObject::ACollector;
             using AGCObjectVisitor = xo::mm::AGCObject::AGCObjectVisitor;
             using VisitReason = xo::mm::AGCObject::VisitReason;
             using Copaque = xo::mm::AGCObject::Copaque;
diff --git a/include/xo/object2/number/IGCObject_DFloat.hpp b/include/xo/object2/number/IGCObject_DFloat.hpp
index 0d9042f..9383014 100644
--- a/include/xo/object2/number/IGCObject_DFloat.hpp
+++ b/include/xo/object2/number/IGCObject_DFloat.hpp
@@ -42,7 +42,6 @@ namespace xo {
             ///@{
             using size_type = xo::mm::AGCObject::size_type;
             using AAllocator = xo::mm::AGCObject::AAllocator;
-            using ACollector = xo::mm::AGCObject::ACollector;
             using AGCObjectVisitor = xo::mm::AGCObject::AGCObjectVisitor;
             using VisitReason = xo::mm::AGCObject::VisitReason;
             using Copaque = xo::mm::AGCObject::Copaque;
diff --git a/include/xo/object2/number/IGCObject_DInteger.hpp b/include/xo/object2/number/IGCObject_DInteger.hpp
index 5d6d944..b116532 100644
--- a/include/xo/object2/number/IGCObject_DInteger.hpp
+++ b/include/xo/object2/number/IGCObject_DInteger.hpp
@@ -41,7 +41,6 @@ namespace xo {
             ///@{
             using size_type = xo::mm::AGCObject::size_type;
             using AAllocator = xo::mm::AGCObject::AAllocator;
-            using ACollector = xo::mm::AGCObject::ACollector;
             using AGCObjectVisitor = xo::mm::AGCObject::AGCObjectVisitor;
             using VisitReason = xo::mm::AGCObject::VisitReason;
             using Copaque = xo::mm::AGCObject::Copaque;
diff --git a/include/xo/object2/sequence/ISequence_Xfer.hpp b/include/xo/object2/sequence/ISequence_Xfer.hpp
index e0511e4..a18ad12 100644
--- a/include/xo/object2/sequence/ISequence_Xfer.hpp
+++ b/include/xo/object2/sequence/ISequence_Xfer.hpp
@@ -9,10 +9,18 @@
  *       [iface_facet_any.hpp.j2]
  *  3. idl for facet methods
  *       [idl/Sequence.json5]
+ *
+ *  variables:
+ *    {facet_hpp_fname} -> Sequence.hpp
+ *    {impl_hpp_subdir} -> sequence
+ *    {facet_ns1} -> xo
+ *    {facet_detail_subdir} -> sequence
+ *    {abstract_facet_fname} -> ASequence.hpp
  **/
 
 #pragma once
 
+#include "ASequence.hpp"
 #include <xo/alloc2/GCObject.hpp>
 
 namespace xo {
diff --git a/src/object2/DArray.cpp b/src/object2/DArray.cpp
index 49c3d64..b22b748 100644
--- a/src/object2/DArray.cpp
+++ b/src/object2/DArray.cpp
@@ -4,7 +4,7 @@
  **/
 
 #include "DArray.hpp"
-#include "gc/RCollector_aux.hpp"
+//#include "gc/RCollector_aux.hpp"
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
 #include <xo/indentlog/print/pretty.hpp>
@@ -16,7 +16,7 @@ namespace xo {
     using xo::print::APrintable;
     using xo::facet::FacetRegistry;
     using xo::mm::AGCObject;
-    using xo::mm::mm_do_assign;
+    //using xo::mm::mm_do_assign;
     using xo::facet::typeseq;
 
     namespace scm {
diff --git a/src/object2/DList.cpp b/src/object2/DList.cpp
index b8494c3..98c82a0 100644
--- a/src/object2/DList.cpp
+++ b/src/object2/DList.cpp
@@ -6,7 +6,13 @@
 #include "DList.hpp"
 #include "list/IPrintable_DList.hpp"
 #include "list/IGCObject_DList.hpp"
+#include <xo/alloc2/GCObjectVisitor.hpp>
 #include <xo/alloc2/GCObject.hpp>
+
+// need Collector for mm_do_assign()
+#include <xo/alloc2/Collector.hpp>
+#include <xo/alloc2/gc/RCollector_aux.hpp>  // for mm_do_assign()
+
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
 #include <xo/facet/facet_implementation.hpp>
@@ -137,7 +143,7 @@ namespace xo {
         {
             scope log(XO_DEBUG(true), xtag("gc.data", gc.data_));
 
-            mm_do_assign(gc, this, &head_, rhs);
+            xo::mm::mm_do_assign(gc, this, &head_, rhs);
         }
 
         void