diff --git a/default.nix b/default.nix
index 59a80c66..e6204753 100644
--- a/default.nix
+++ b/default.nix
@@ -150,6 +150,7 @@ let
             xo-allocutil      = self.callPackage pkgs/xo-allocutil.nix      { stdenv = jitStdenv; };
             xo-alloc          = self.callPackage pkgs/xo-alloc.nix          { stdenv = jitStdenv; buildDocs = true; };
             xo-alloc2         = self.callPackage pkgs/xo-alloc2.nix         { stdenv = jitStdenv; buildDocs = true; };
+            xo-stringtable2   = self.callPackage pkgs/xo-stringtable2.nix   { stdenv = jitStdenv; };
             xo-gc             = self.callPackage pkgs/xo-gc.nix             { stdenv = jitStdenv; buildDocs = true; };
             xo-object         = self.callPackage pkgs/xo-object.nix         { stdenv = jitStdenv; };
             xo-object2        = self.callPackage pkgs/xo-object2.nix        { stdenv = jitStdenv; };
@@ -500,6 +501,7 @@ in
     allocutil      = pkgs.xo-allocutil;
     alloc          = pkgs.xo-alloc;
     alloc2         = pkgs.xo-alloc2;
+    stringtable2   = pkgs.xo-stringtable2;
     gc             = pkgs.xo-gc;
     object         = pkgs.xo-object;
     object2        = pkgs.xo-object2;
diff --git a/pkgs/xo-object2.nix b/pkgs/xo-object2.nix
index 93de3b0c..7a6b22fa 100644
--- a/pkgs/xo-object2.nix
+++ b/pkgs/xo-object2.nix
@@ -10,8 +10,9 @@
 #  xo-reflectutil,
 #  xo-alloc,
   #  xo-randomgen,
+  xo-stringtable2,
   xo-reflect,
-  xo-gc,
+  xo-alloc2,
   xo-printable2,
   xo-facet,
   xo-subsys,
@@ -40,7 +41,8 @@ stdenv.mkDerivation (finalattrs:
     ];
     propagatedBuildInputs = [
       xo-reflect
-      xo-gc
+      xo-alloc2
+      xo-stringtable2
       xo-printable2
       xo-subsys
       xo-facet
diff --git a/xo-alloc2/idl/GCObject.json5 b/xo-alloc2/idl/GCObject.json5
index 43747582..0bbb170d 100644
--- a/xo-alloc2/idl/GCObject.json5
+++ b/xo-alloc2/idl/GCObject.json5
@@ -1,24 +1,26 @@
 {
     mode: "facet",
-    output_cpp_dir: "src/gc",
-    output_hpp_dir: "include/xo/gc",
-    output_impl_subdir: "detail",
+    output_cpp_dir: "src/alloc2",
+    output_hpp_dir: "include/xo/alloc2",
+    output_impl_subdir: "gc",
     includes: [
         "<xo/alloc2/Allocator.hpp>",
-        "<xo/gc/Collector.hpp>",
+        "<xo/alloc2/Collector.hpp>",
         "<cstdint>",
         "<cstddef>",
     ],
     // extra includes in GCObject.hpp, if any
-    user_hpp_includes: [],
+    user_hpp_includes: [
+        "\"gc/RCollector_aux.hpp\"",
+    ],
     namespace1: "xo",
     namespace2: "mm",
     pretext: [
         "namespace xo { namespace mm { class ACollector; }}",
     ],
     facet: "GCObject",
-    detail_subdir: "detail",
-    brief: "xxx",
+    detail_subdir: "gc",
+    brief: "gc-aware object, providing collector hooks",
     using_doxygen: true,
     doc: [
         "GC hooks for collector-aware data"
diff --git a/xo-alloc2/include/xo/alloc2/GCObject.hpp b/xo-alloc2/include/xo/alloc2/GCObject.hpp
index b7758ace..4733b019 100644
--- a/xo-alloc2/include/xo/alloc2/GCObject.hpp
+++ b/xo-alloc2/include/xo/alloc2/GCObject.hpp
@@ -18,30 +18,6 @@
 #include "gc/IGCObject_Xfer.hpp"
 #include "gc/RGCObject.hpp"
 
-namespace xo {
-    namespace mm {
-        /** defined here to avoid #include cycle, since
-         *  template obj<AGCObject,DRepr> awkward to make available there
-         **/
-        template <typename Object>
-        template <typename DRepr>
-        void
-        RCollector<Object>::forward_inplace(xo::facet::obj<AGCObject,DRepr> * p_obj)
-        {
-            this->forward_inplace(p_obj->iface(), (void **)&(p_obj->data_));
-        }
-
-        template <typename Object>
-        template <typename DRepr>
-        void
-        RCollector<Object>::forward_inplace(DRepr ** p_repr)
-        {
-            // fetch static interface for DRepr
-            auto iface = xo::facet::impl_for<AGCObject,DRepr>();
-
-            this->forward_inplace(&iface, (void **)p_repr);
-        }
-    }
-}
+#include "gc/RCollector_aux.hpp"
 
 /* end GCObject.hpp */
diff --git a/xo-gc/include/xo/gc/GCObjectConversion.hpp b/xo-alloc2/include/xo/alloc2/GCObjectConversion.hpp
similarity index 100%
rename from xo-gc/include/xo/gc/GCObjectConversion.hpp
rename to xo-alloc2/include/xo/alloc2/GCObjectConversion.hpp
diff --git a/xo-alloc2/include/xo/alloc2/gc/AGCObject.hpp b/xo-alloc2/include/xo/alloc2/gc/AGCObject.hpp
index 87fc6664..c420f0ff 100644
--- a/xo-alloc2/include/xo/alloc2/gc/AGCObject.hpp
+++ b/xo-alloc2/include/xo/alloc2/gc/AGCObject.hpp
@@ -31,7 +31,7 @@ using Copaque = const void *;
 using Opaque = void *;
 
 /**
-   GC hooks for collector-aware data
+GC hooks for collector-aware data
 **/
 class AGCObject {
 public:
diff --git a/xo-alloc2/include/xo/alloc2/gc/RCollector_aux.hpp b/xo-alloc2/include/xo/alloc2/gc/RCollector_aux.hpp
new file mode 100644
index 00000000..b85c73b5
--- /dev/null
+++ b/xo-alloc2/include/xo/alloc2/gc/RCollector_aux.hpp
@@ -0,0 +1,40 @@
+/** @file RCollector_aux.hpp
+ *
+ *  Out-of-line definitions for RCollector template methods
+ *  that depend on RGCObject (avoiding #include cycle in RCollector.hpp).
+ *
+ *  Included via user_hpp_includes in GCObject.json5.
+ *
+ *  @author Roland Conybeare
+ **/
+
+#pragma once
+
+namespace xo {
+    namespace mm {
+        /** defined here to avoid #include cycle, since
+         *  template obj<AGCObject,DRepr> awkward to make available
+         *  in RCollector.hpp
+         **/
+        template <typename Object>
+        template <typename DRepr>
+        void
+        RCollector<Object>::forward_inplace(xo::facet::obj<AGCObject,DRepr> * p_obj)
+        {
+            this->forward_inplace(p_obj->iface(), (void **)&(p_obj->data_));
+        }
+
+        template <typename Object>
+        template <typename DRepr>
+        void
+        RCollector<Object>::forward_inplace(DRepr ** p_repr)
+        {
+            // fetch static interface for DRepr
+            auto iface = xo::facet::impl_for<AGCObject,DRepr>();
+
+            this->forward_inplace(&iface, (void **)p_repr);
+        }
+    }
+}
+
+/* end RCollector_aux.hpp */
diff --git a/xo-alloc2/include/xo/gc/GCObject.hpp b/xo-alloc2/include/xo/gc/GCObject.hpp
deleted file mode 100644
index 759e9376..00000000
--- a/xo-alloc2/include/xo/gc/GCObject.hpp
+++ /dev/null
@@ -1,22 +0,0 @@
-/** @file GCObject.hpp
- *
- *  Generated automagically from ingredients:
- *  1. code generator:
- *       [xo-facet/codegen/genfacet]
- *     arguments:
- *       --input [idl/GCObject.json5]
- *  2. jinja2 template for facet .hpp file:
- *       [facet.hpp.j2]
- *  3. idl for facet methods
- *       [idl/GCObject.json5]
- **/
-
-#pragma once
-
-#include "detail/AGCObject.hpp"
-#include "detail/IGCObject_Any.hpp"
-#include "detail/IGCObject_Xfer.hpp"
-#include "detail/RGCObject.hpp"
-
-
-/* end GCObject.hpp */
diff --git a/xo-alloc2/include/xo/gc/detail/AGCObject.hpp b/xo-alloc2/include/xo/gc/detail/AGCObject.hpp
deleted file mode 100644
index 6f6e7b92..00000000
--- a/xo-alloc2/include/xo/gc/detail/AGCObject.hpp
+++ /dev/null
@@ -1,87 +0,0 @@
-/** @file AGCObject.hpp
- *
- *  Generated automagically from ingredients:
- *  1. code generator:
- *       [xo-facet/codegen/genfacet]
- *     arguments:
- *       --input [idl/GCObject.json5]
- *  2. jinja2 template for abstract facet .hpp file:
- *       [abstract_facet.hpp.j2]
- *  3. idl for facet methods
- *       [idl/GCObject.json5]
- **/
-
-#pragma once
-
-// includes (via {facet_includes})
-#include <xo/alloc2/Allocator.hpp>
-#include <xo/gc/Collector.hpp>
-#include <cstdint>
-#include <cstddef>
-#include <xo/facet/obj.hpp>
-#include <xo/facet/facet_implementation.hpp>
-#include <xo/facet/typeseq.hpp>
-
-namespace xo { namespace mm { class ACollector; }}
-
-namespace xo {
-namespace mm {
-
-using Copaque = const void *;
-using Opaque = void *;
-
-/**
-GC hooks for collector-aware data
-**/
-class AGCObject {
-public:
-    /** @defgroup mm-gcobject-type-traits **/
-    ///@{
-    // types
-    /** integer identifying a type **/
-    using typeseq = xo::facet::typeseq;
-    using Copaque = const void *;
-    using Opaque = void *;
-    /** type for an amount of memory **/
-    using size_type = std::size_t;
-    /** fomo allocator type **/
-    using AAllocator = xo::mm::AAllocator;
-    /** fomo collector type **/
-    using ACollector = xo::mm::ACollector;
-    ///@}
-
-    /** @defgroup mm-gcobject-methods **/
-    ///@{
-    // const methods
-    /** RTTI: unique id# for actual runtime data representation **/
-    virtual typeseq _typeseq() const noexcept = 0;
-    /** destroy instance @p d; calls c++ dtor only for actual runtime type; does not recover memory **/
-    virtual void _drop(Opaque d) const noexcept = 0;
-    /** memory consumption for this instance **/
-    virtual size_type shallow_size(Copaque data)  const  noexcept = 0;
-    /** copy instance using allocator **/
-    virtual Opaque shallow_copy(Copaque data, obj<AAllocator> mm)  const  noexcept = 0;
-
-    // nonconst methods
-    /** during GC: forward immdiate children **/
-    virtual size_type forward_children(Opaque data, obj<ACollector> gc)  const  noexcept = 0;
-    ///@}
-}; /*AGCObject*/
-
-/** Implementation IGCObject_DRepr of AGCObject for state DRepr
- *  should provide a specialization:
- *
- *    template <>
- *    struct xo::facet::FacetImplementation<AGCObject, DRepr> {
- *        using Impltype = IGCObject_DRepr;
- *    };
- *
- *  then IGCObject_ImplType<DRepr> --> IGCObject_DRepr
- **/
-template <typename DRepr>
-using IGCObject_ImplType = xo::facet::FacetImplType<AGCObject, DRepr>;
-
-} /*namespace mm*/
-} /*namespace xo*/
-
-/* AGCObject.hpp */
diff --git a/xo-alloc2/include/xo/gc/detail/IGCObject_Any.hpp b/xo-alloc2/include/xo/gc/detail/IGCObject_Any.hpp
deleted file mode 100644
index 9ff7bb2e..00000000
--- a/xo-alloc2/include/xo/gc/detail/IGCObject_Any.hpp
+++ /dev/null
@@ -1,93 +0,0 @@
-/** @file IGCObject_Any.hpp
- *
- *  Generated automagically from ingredients:
- *  1. code generator:
- *       [xo-facet/codegen/genfacet]
- *     arguments:
- *       --input [idl/GCObject.json5]
- *  2. jinja2 template for abstract facet .hpp file:
- *       [iface_facet_any.hpp.j2]
- *  3. idl for facet methods
- *       [idl/GCObject.json5]
- **/
-
-#pragma once
-
-#include "AGCObject.hpp"
-#include <xo/facet/obj.hpp>
-
-namespace xo { namespace mm { class IGCObject_Any; } }
-
-namespace xo {
-namespace facet {
-
-template <>
-struct FacetImplementation<xo::mm::AGCObject,
-                           DVariantPlaceholder>
-{
-    using ImplType = xo::mm::IGCObject_Any;
-};
-
-}
-}
-
-namespace xo {
-namespace mm {
-
-    /** @class IGCObject_Any
-     *  @brief AGCObject implementation for empty variant instance
-     **/
-    class IGCObject_Any : public AGCObject {
-    public:
-        /** @defgroup mm-gcobject-any-type-traits **/
-        ///@{
-
-        /** integer identifying a type **/
-        using typeseq = xo::facet::typeseq;
-        using size_type = AGCObject::size_type;
-        using AAllocator = AGCObject::AAllocator;
-        using ACollector = AGCObject::ACollector;
-
-        ///@}
-        /** @defgroup mm-gcobject-any-methods **/
-        ///@{
-
-        const AGCObject * iface() const { return std::launder(this); }
-
-        // from AGCObject
-
-        // builtin methods
-        typeseq _typeseq() const noexcept override { return s_typeseq; }
-        [[noreturn]] void _drop(Opaque) const noexcept override { _fatal(); }
-
-        // const methods
-        [[noreturn]] size_type shallow_size(Copaque)  const  noexcept override { _fatal(); }
-        [[noreturn]] Opaque shallow_copy(Copaque, obj<AAllocator>)  const  noexcept override { _fatal(); }
-
-        // nonconst methods
-        [[noreturn]] size_type forward_children(Opaque, obj<ACollector>)  const  noexcept override;
-
-        ///@}
-
-    private:
-        /** @defgraoup mm-gcobject-any-private-methods **/
-        ///@{
-
-        [[noreturn]] static void _fatal();
-
-        ///@}
-
-    public:
-        /** @defgroup mm-gcobject-any-member-vars **/
-        ///@{
-
-        static typeseq s_typeseq;
-        static bool _valid;
-
-        ///@}
-    };
-
-} /*namespace mm */
-} /*namespace xo */
-
-/* IGCObject_Any.hpp */
diff --git a/xo-alloc2/include/xo/gc/detail/IGCObject_Xfer.hpp b/xo-alloc2/include/xo/gc/detail/IGCObject_Xfer.hpp
deleted file mode 100644
index 7f094ab7..00000000
--- a/xo-alloc2/include/xo/gc/detail/IGCObject_Xfer.hpp
+++ /dev/null
@@ -1,95 +0,0 @@
-/** @file IGCObject_Xfer.hpp
- *
- *  Generated automagically from ingredients:
- *  1. code generator:
- *       [xo-facet/codegen/genfacet]
- *     arguments:
- *       --input [idl/GCObject.json5]
- *  2. jinja2 template for abstract facet .hpp file:
- *       [iface_facet_any.hpp.j2]
- *  3. idl for facet methods
- *       [idl/GCObject.json5]
- **/
-
-#pragma once
-
-#include <xo/alloc2/Allocator.hpp>
-#include <xo/gc/Collector.hpp>
-#include <cstdint>
-#include <cstddef>
-
-namespace xo {
-namespace mm {
-    /** @class IGCObject_Xfer
-     **/
-    template <typename DRepr, typename IGCObject_DRepr>
-    class IGCObject_Xfer : public AGCObject {
-    public:
-        /** @defgroup mm-gcobject-xfer-type-traits **/
-        ///@{
-        /** actual implementation (not generated; often delegates to DRepr) **/
-        using Impl = IGCObject_DRepr;
-        /** integer identifying a type **/
-        using typeseq = AGCObject::typeseq;
-        using size_type = AGCObject::size_type;
-        using AAllocator = AGCObject::AAllocator;
-        using ACollector = AGCObject::ACollector;
-        ///@}
-
-        /** @defgroup mm-gcobject-xfer-methods **/
-        ///@{
-
-        static const DRepr & _dcast(Copaque d) { return *(const DRepr *)d; }
-        static DRepr & _dcast(Opaque d) { return *(DRepr *)d; }
-
-        // from AGCObject
-
-        // builtin methods
-        typeseq _typeseq() const noexcept override { return s_typeseq; }
-        void _drop(Opaque d) const noexcept override { _dcast(d).~DRepr(); }
-
-        // const methods
-        size_type shallow_size(Copaque data)  const  noexcept override {
-            return I::shallow_size(_dcast(data));
-        }
-        Opaque shallow_copy(Copaque data, obj<AAllocator> mm)  const  noexcept override {
-            return I::shallow_copy(_dcast(data), mm);
-        }
-
-        // non-const methods
-        size_type forward_children(Opaque data, obj<ACollector> gc)  const  noexcept override {
-            return I::forward_children(_dcast(data), gc);
-        }
-
-        ///@}
-
-    private:
-        using I = Impl;
-
-    public:
-        /** @defgroup mm-gcobject-xfer-member-vars **/
-        ///@{
-
-        /** typeseq for template parameter DRepr **/
-        static typeseq s_typeseq;
-        /** true iff satisfies facet implementation **/
-        static bool _valid;
-
-        ///@}
-    };
-
-    template <typename DRepr, typename IGCObject_DRepr>
-    xo::facet::typeseq
-    IGCObject_Xfer<DRepr, IGCObject_DRepr>::s_typeseq
-      = xo::facet::typeseq::id<DRepr>();
-
-    template <typename DRepr, typename IGCObject_DRepr>
-    bool
-    IGCObject_Xfer<DRepr, IGCObject_DRepr>::_valid
-      = xo::facet::valid_facet_implementation<AGCObject,
-                                              IGCObject_Xfer>();
-
-} /*namespace mm */
-} /*namespace xo*/
-
-/* end IGCObject_Xfer.hpp */
diff --git a/xo-alloc2/include/xo/gc/detail/RGCObject.hpp b/xo-alloc2/include/xo/gc/detail/RGCObject.hpp
deleted file mode 100644
index d24994a8..00000000
--- a/xo-alloc2/include/xo/gc/detail/RGCObject.hpp
+++ /dev/null
@@ -1,93 +0,0 @@
-/** @file RGCObject.hpp
- *
- *  Generated automagically from ingredients:
- *  1. code generator:
- *       [xo-facet/codegen/genfacet]
- *     arguments:
- *       --input [idl/GCObject.json5]
- *  2. jinja2 template for abstract facet .hpp file:
- *       [iface_facet_any.hpp.j2]
- *  3. idl for facet methods
- *       [idl/GCObject.json5]
- **/
-
-#pragma once
-
-#include "AGCObject.hpp"
-
-namespace xo {
-namespace mm {
-
-/** @class RGCObject
- **/
-template <typename Object>
-class RGCObject : public Object {
-private:
-    using O = Object;
-
-public:
-    /** @defgroup mm-gcobject-router-type-traits **/
-    ///@{
-    using ObjectType = Object;
-    using DataPtr = Object::DataPtr;
-    using typeseq = xo::reflect::typeseq;
-    using size_type = AGCObject::size_type;
-    using AAllocator = AGCObject::AAllocator;
-    using ACollector = AGCObject::ACollector;
-    ///@}
-
-    /** @defgroup mm-gcobject-router-ctors **/
-    ///@{
-    RGCObject() {}
-    RGCObject(Object::DataPtr data) : Object{std::move(data)} {}
-    RGCObject(const AGCObject * iface, void * data)
-      requires std::is_same_v<typename Object::DataType, xo::facet::DVariantPlaceholder>
-      : Object(iface, data) {}
-
-    ///@}
-    /** @defgroup mm-gcobject-router-methods **/
-    ///@{
-
-    // explicit injected content
-
-    // builtin methods
-    typeseq _typeseq() const noexcept { return O::iface()->_typeseq(); }
-    void _drop() const noexcept { O::iface()->_drop(O::data()); }
-
-    // const methods
-    size_type shallow_size()  const  noexcept {
-        return O::iface()->shallow_size(O::data());
-    }
-    Opaque shallow_copy(obj<AAllocator> mm)  const  noexcept {
-        return O::iface()->shallow_copy(O::data(), mm);
-    }
-
-    // non-const methods (still const in router!)
-    size_type forward_children(obj<ACollector> gc)  noexcept {
-        return O::iface()->forward_children(O::data(), gc);
-    }
-
-    ///@}
-    /** @defgroup mm-gcobject-member-vars **/
-    ///@{
-
-    static bool _valid;
-
-    ///@}
-};
-
-template <typename Object>
-bool
-RGCObject<Object>::_valid = xo::facet::valid_object_router<Object>();
-
-} /*namespace mm*/
-} /*namespace xo*/
-
-namespace xo { namespace facet {
-    template <typename Object>
-    struct RoutingFor<xo::mm::AGCObject, Object> {
-        using RoutingType = xo::mm::RGCObject<Object>;
-    };
-} }
-
-/* end RGCObject.hpp */
diff --git a/xo-gc/include/xo/gc/detail/ICollector_DX1Collector.hpp b/xo-gc/include/xo/gc/detail/ICollector_DX1Collector.hpp
index 0475a535..1db50e23 100644
--- a/xo-gc/include/xo/gc/detail/ICollector_DX1Collector.hpp
+++ b/xo-gc/include/xo/gc/detail/ICollector_DX1Collector.hpp
@@ -3,6 +3,8 @@
  *  @author Roland Conybeare, Dec 2025
  **/
 
+#pragma once
+
 #include <xo/alloc2/gc/ACollector.hpp>
 #include <xo/alloc2/gc/ICollector_Xfer.hpp>
 #include "DX1Collector.hpp"
diff --git a/xo-object2/CMakeLists.txt b/xo-object2/CMakeLists.txt
index 1735dd5b..09ebb96e 100644
--- a/xo-object2/CMakeLists.txt
+++ b/xo-object2/CMakeLists.txt
@@ -48,7 +48,7 @@ xo_add_genfacetimpl(
 # note: manual target; generated code committed to git
 xo_add_genfacetimpl(
     TARGET xo-object2-facetimpl-gcobject-list
-    FACET_PKG xo_gc
+    FACET_PKG xo_alloc2
     FACET GCObject
     REPR List
     INPUT idl/IGCObject_DList.json5
@@ -68,7 +68,7 @@ xo_add_genfacetimpl(
 # note: manual target; generated code committed to git
 xo_add_genfacetimpl(
     TARGET xo-object2-facetimpl-gcobject-boolean
-    FACET_PKG xo_gc
+    FACET_PKG xo_alloc2
     FACET GCObject
     REPR Boolean
     INPUT idl/IGCObject_DBoolean.json5
@@ -88,7 +88,7 @@ xo_add_genfacetimpl(
 # note: manual target; generated code committed to git
 xo_add_genfacetimpl(
     TARGET xo-object2-facetimpl-gcobject-float
-    FACET_PKG xo_gc
+    FACET_PKG xo_alloc2
     FACET GCObject
     REPR Float
     INPUT idl/IGCObject_DFloat.json5
@@ -108,7 +108,7 @@ xo_add_genfacetimpl(
 # note: manual target; generated code committed to git
 xo_add_genfacetimpl(
     TARGET xo-object2-facetimpl-gcobject-integer
-    FACET_PKG xo_gc
+    FACET_PKG xo_alloc2
     FACET GCObject
     REPR Integer
     INPUT idl/IGCObject_DInteger.json5
@@ -137,7 +137,7 @@ xo_add_genfacetimpl(
 # note: manual target; generated code committed to git
 xo_add_genfacetimpl(
     TARGET xo-object2-facetimpl-gcobject-array
-    FACET_PKG xo_gc
+    FACET_PKG xo_alloc2
     FACET GCObject
     REPR Array
     INPUT idl/IGCObject_DArray.json5
@@ -157,7 +157,7 @@ xo_add_genfacetimpl(
 # note: manual target; generated code committed to git
 xo_add_genfacetimpl(
     TARGET xo-object2-facetimpl-gcobject-dictionary
-    FACET_PKG xo_gc
+    FACET_PKG xo_alloc2
     FACET GCObject
     REPR Dictionary
     INPUT idl/IGCObject_DDictionary.json5
@@ -177,7 +177,7 @@ xo_add_genfacetimpl(
 # note: manual target; generated code committed to git
 xo_add_genfacetimpl(
     TARGET xo-object2-facetimpl-gcobject-runtimeerror
-    FACET_PKG xo_gc
+    FACET_PKG xo_alloc2
     FACET GCObject
     REPR RuntimeError
     INPUT idl/IGCObject_DRuntimeError.json5
diff --git a/xo-object2/cmake/xo_object2Config.cmake.in b/xo-object2/cmake/xo_object2Config.cmake.in
index 78ee9e0f..b34f76ff 100644
--- a/xo-object2/cmake/xo_object2Config.cmake.in
+++ b/xo-object2/cmake/xo_object2Config.cmake.in
@@ -2,8 +2,8 @@
 
 include(CMakeFindDependencyMacro)
 find_dependency(reflect)
-find_dependency(xo_gc)
 find_dependency(xo_stringtable2)
+find_dependency(xo_alloc2)
 find_dependency(xo_printable2)
 find_dependency(subsys)
 find_dependency(indentlog)
diff --git a/xo-object2/idl/IGCObject_DArray.json5 b/xo-object2/idl/IGCObject_DArray.json5
index bef5bd62..96507a75 100644
--- a/xo-object2/idl/IGCObject_DArray.json5
+++ b/xo-object2/idl/IGCObject_DArray.json5
@@ -4,7 +4,7 @@
     output_hpp_dir: "include/xo/object2",
     output_impl_subdir: "array",
     includes: [
-        "<xo/gc/GCObject.hpp>",
+        "<xo/alloc2/GCObject.hpp>",
         "<xo/alloc2/Allocator.hpp>"
     ],
     local_types: [ ],
diff --git a/xo-object2/idl/IGCObject_DBoolean.json5 b/xo-object2/idl/IGCObject_DBoolean.json5
index c9aaf26b..c739ccda 100644
--- a/xo-object2/idl/IGCObject_DBoolean.json5
+++ b/xo-object2/idl/IGCObject_DBoolean.json5
@@ -4,8 +4,8 @@
     output_hpp_dir: "include/xo/object2",
     output_impl_subdir: "boolean",
     includes: [
-        "<xo/gc/GCObject.hpp>",
-        "<xo/alloc2/Allocator.hpp>"
+//        "<xo/alloc2/GCObject.hpp>",
+//        "<xo/alloc2/Allocator.hpp>"
     ],
     local_types: [ ],
     namespace1: "xo",
diff --git a/xo-object2/idl/IGCObject_DDictionary.json5 b/xo-object2/idl/IGCObject_DDictionary.json5
index 636413be..ebf8fd8b 100644
--- a/xo-object2/idl/IGCObject_DDictionary.json5
+++ b/xo-object2/idl/IGCObject_DDictionary.json5
@@ -4,7 +4,7 @@
     output_hpp_dir: "include/xo/object2",
     output_impl_subdir: "dictionary",
     includes: [
-        "<xo/gc/GCObject.hpp>",
+        "<xo/alloc2/GCObject.hpp>",
         "<xo/alloc2/Allocator.hpp>"
     ],
     local_types: [ ],
diff --git a/xo-object2/idl/IGCObject_DFloat.json5 b/xo-object2/idl/IGCObject_DFloat.json5
index eec1e3e3..2255f414 100644
--- a/xo-object2/idl/IGCObject_DFloat.json5
+++ b/xo-object2/idl/IGCObject_DFloat.json5
@@ -5,7 +5,7 @@
     output_impl_subdir: "number",
     includes: [
         "<xo/object2/number/GCObjectConversion_DFloat.hpp>",
-        "<xo/gc/GCObject.hpp>",
+        "<xo/alloc2/GCObject.hpp>",
         "<xo/alloc2/Allocator.hpp>"
     ],
     local_types: [ ],
diff --git a/xo-object2/idl/IGCObject_DInteger.json5 b/xo-object2/idl/IGCObject_DInteger.json5
index 37d603e5..18093306 100644
--- a/xo-object2/idl/IGCObject_DInteger.json5
+++ b/xo-object2/idl/IGCObject_DInteger.json5
@@ -4,7 +4,7 @@
     output_hpp_dir: "include/xo/object2",
     output_impl_subdir: "number",
     includes: [
-        "<xo/gc/GCObject.hpp>",
+        "<xo/alloc2/GCObject.hpp>",
         "<xo/alloc2/Allocator.hpp>"
     ],
     local_types: [ ],
diff --git a/xo-object2/idl/IGCObject_DList.json5 b/xo-object2/idl/IGCObject_DList.json5
index 28fb3352..ecb48980 100644
--- a/xo-object2/idl/IGCObject_DList.json5
+++ b/xo-object2/idl/IGCObject_DList.json5
@@ -4,7 +4,7 @@
     output_hpp_dir: "include/xo/object2",
     output_impl_subdir: "list",
     includes: [
-//        "<xo/gc/GCObject.hpp>",
+//        "<xo/alloc2/GCObject.hpp>",
 //        "<xo/alloc2/Allocator.hpp>"
     ],
     local_types: [ ],
diff --git a/xo-object2/idl/IGCObject_DRuntimeError.json5 b/xo-object2/idl/IGCObject_DRuntimeError.json5
index cfcbe9f6..a0e15042 100644
--- a/xo-object2/idl/IGCObject_DRuntimeError.json5
+++ b/xo-object2/idl/IGCObject_DRuntimeError.json5
@@ -4,7 +4,7 @@
     output_hpp_dir: "include/xo/object2",
     output_impl_subdir: "error",
     includes: [
-//        "<xo/gc/GCObject.hpp>",
+//        "<xo/alloc2/GCObject.hpp>",
 //        "<xo/alloc2/Allocator.hpp>"
     ],
     local_types: [ ],
diff --git a/xo-object2/idl/Sequence.json5 b/xo-object2/idl/Sequence.json5
index 20271697..0b022f0b 100644
--- a/xo-object2/idl/Sequence.json5
+++ b/xo-object2/idl/Sequence.json5
@@ -3,7 +3,7 @@
     output_cpp_dir: "src/object2",
     output_hpp_dir: "include/xo/object2",
     output_impl_subdir: "sequence",
-    includes: ["<xo/gc/GCObject.hpp>"],
+    includes: ["<xo/alloc2/GCObject.hpp>"],
     // extra includes in Sequence.hpp, if any
     user_hpp_includes: [],
     namespace1: "xo",
diff --git a/xo-object2/include/xo/object2/array/IGCObject_DArray.hpp b/xo-object2/include/xo/object2/array/IGCObject_DArray.hpp
index 08f78aa8..6eb571e5 100644
--- a/xo-object2/include/xo/object2/array/IGCObject_DArray.hpp
+++ b/xo-object2/include/xo/object2/array/IGCObject_DArray.hpp
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
+/* end */
\ No newline at end of file
diff --git a/xo-object2/include/xo/object2/boolean/IGCObject_DBoolean.hpp b/xo-object2/include/xo/object2/boolean/IGCObject_DBoolean.hpp
index 358aad18..9afd9646 100644
--- a/xo-object2/include/xo/object2/boolean/IGCObject_DBoolean.hpp
+++ b/xo-object2/include/xo/object2/boolean/IGCObject_DBoolean.hpp
@@ -14,8 +14,6 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/alloc2/GCObject.hpp>
-#include <xo/alloc2/Allocator.hpp>
 #include "DBoolean.hpp"
 
 namespace xo { namespace scm { class IGCObject_DBoolean; } }
@@ -64,4 +62,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
+/* end */
\ No newline at end of file
diff --git a/xo-object2/include/xo/object2/dictionary/IGCObject_DDictionary.hpp b/xo-object2/include/xo/object2/dictionary/IGCObject_DDictionary.hpp
index 7fe1bc55..2d69f990 100644
--- a/xo-object2/include/xo/object2/dictionary/IGCObject_DDictionary.hpp
+++ b/xo-object2/include/xo/object2/dictionary/IGCObject_DDictionary.hpp
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
+/* end */
\ No newline at end of file
diff --git a/xo-object2/include/xo/object2/number/GCObjectConversion_DFloat.hpp b/xo-object2/include/xo/object2/number/GCObjectConversion_DFloat.hpp
index 959eeca0..4cc47517 100644
--- a/xo-object2/include/xo/object2/number/GCObjectConversion_DFloat.hpp
+++ b/xo-object2/include/xo/object2/number/GCObjectConversion_DFloat.hpp
@@ -7,7 +7,7 @@
 
 #include "DFloat.hpp"
 #include "number/IGCObject_DFloat.hpp"
-#include <xo/gc/GCObjectConversion.hpp>
+#include <xo/alloc2/GCObjectConversion.hpp>
 
 namespace xo {
     namespace scm {
diff --git a/xo-object2/include/xo/object2/number/GCObjectConversion_DInteger.hpp b/xo-object2/include/xo/object2/number/GCObjectConversion_DInteger.hpp
index 458312c9..5b01e571 100644
--- a/xo-object2/include/xo/object2/number/GCObjectConversion_DInteger.hpp
+++ b/xo-object2/include/xo/object2/number/GCObjectConversion_DInteger.hpp
@@ -7,7 +7,7 @@
 
 #include "DInteger.hpp"
 #include "number/IGCObject_DInteger.hpp"
-#include <xo/gc/GCObjectConversion.hpp>
+#include <xo/alloc2/GCObjectConversion.hpp>
 
 namespace xo {
     namespace scm {
diff --git a/xo-object2/include/xo/object2/number/IGCObject_DFloat.hpp b/xo-object2/include/xo/object2/number/IGCObject_DFloat.hpp
index b8e15b73..ee2eecfd 100644
--- a/xo-object2/include/xo/object2/number/IGCObject_DFloat.hpp
+++ b/xo-object2/include/xo/object2/number/IGCObject_DFloat.hpp
@@ -65,4 +65,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
+/* end */
\ No newline at end of file
diff --git a/xo-object2/include/xo/object2/number/IGCObject_DInteger.hpp b/xo-object2/include/xo/object2/number/IGCObject_DInteger.hpp
index fd2ea642..799372ad 100644
--- a/xo-object2/include/xo/object2/number/IGCObject_DInteger.hpp
+++ b/xo-object2/include/xo/object2/number/IGCObject_DInteger.hpp
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
+/* end */
\ No newline at end of file
diff --git a/xo-object2/src/object2/CMakeLists.txt b/xo-object2/src/object2/CMakeLists.txt
index f0aaefb7..b2370cf4 100644
--- a/xo-object2/src/object2/CMakeLists.txt
+++ b/xo-object2/src/object2/CMakeLists.txt
@@ -45,8 +45,8 @@ set(SELF_SRCS
 xo_add_shared_library4(${SELF_LIB} ${PROJECT_NAME}Targets ${PROJECT_VERSION} 1 ${SELF_SRCS})
 # note: deps here must also appear in cmake/xo_object2Config.cmake.in
 xo_dependency(${SELF_LIB} reflect)
-xo_dependency(${SELF_LIB} xo_gc)
 xo_dependency(${SELF_LIB} xo_stringtable2)
+xo_dependency(${SELF_LIB} xo_alloc2)
 xo_dependency(${SELF_LIB} xo_printable2)
 xo_dependency(${SELF_LIB} subsys)
 xo_dependency(${SELF_LIB} indentlog)
diff --git a/xo-object2/src/object2/ISequence_Any.cpp b/xo-object2/src/object2/ISequence_Any.cpp
index 77da7d31..5e0583f0 100644
--- a/xo-object2/src/object2/ISequence_Any.cpp
+++ b/xo-object2/src/object2/ISequence_Any.cpp
@@ -3,8 +3,8 @@
  **/
 
 #include "sequence/ISequence_Any.hpp"
-#include <exception>
 #include <iostream>
+#include <exception>
 
 namespace xo {
 namespace scm {
diff --git a/xo-object2/utest/CMakeLists.txt b/xo-object2/utest/CMakeLists.txt
index 7843e0e9..e4532c26 100644
--- a/xo-object2/utest/CMakeLists.txt
+++ b/xo-object2/utest/CMakeLists.txt
@@ -12,5 +12,6 @@ set(UTEST_SRCS
 
 xo_add_utest_executable(${UTEST_EXE} ${UTEST_SRCS})
 xo_self_dependency(${UTEST_EXE} xo_object2)
+xo_dependency(${UTEST_EXE} xo_gc)
 #xo_dependency(${UTEST_EXE} randomgen)
 xo_external_target_dependency(${UTEST_EXE} Catch2 Catch2::Catch2)
diff --git a/xo-object2/utest/Printable.test.cpp b/xo-object2/utest/Printable.test.cpp
index 15de595d..edf230a4 100644
--- a/xo-object2/utest/Printable.test.cpp
+++ b/xo-object2/utest/Printable.test.cpp
@@ -20,7 +20,8 @@
 #include <xo/object2/number/IGCObject_DInteger.hpp>
 
 #include <xo/alloc2/Collector.hpp>
-#include <xo/gc/DX1Collector.hpp>
+
+#include <xo/gc/X1Collector.hpp>
 #include <xo/gc/detail/IAllocator_DX1Collector.hpp>
 #include <xo/gc/detail/ICollector_DX1Collector.hpp>
 
diff --git a/xo-procedure2/include/xo/procedure2/DPrimitive.hpp b/xo-procedure2/include/xo/procedure2/DPrimitive.hpp
index 5003ba02..17c19435 100644
--- a/xo-procedure2/include/xo/procedure2/DPrimitive.hpp
+++ b/xo-procedure2/include/xo/procedure2/DPrimitive.hpp
@@ -7,7 +7,7 @@
 
 #include "RuntimeContext.hpp"
 #include <xo/object2/DArray.hpp>
-#include <xo/gc/GCObjectConversion.hpp>
+#include <xo/alloc2/GCObjectConversion.hpp>
 #include <xo/alloc2/GCObject.hpp>
 #include <xo/reflect/Reflect.hpp>
 #include <xo/alloc2/Allocator.hpp>
diff --git a/xo-procedure2/src/procedure2/init_primitives.cpp b/xo-procedure2/src/procedure2/init_primitives.cpp
index 1fd3950c..142ad868 100644
--- a/xo-procedure2/src/procedure2/init_primitives.cpp
+++ b/xo-procedure2/src/procedure2/init_primitives.cpp
@@ -6,13 +6,11 @@
 #include "init_primitives.hpp"
 #include "DPrimitive.hpp"
 #include <xo/object2/Float.hpp>
-//#include <xo/object2/number/IGCObject_DFloat.hpp>
 #include <xo/object2/Integer.hpp>
-//#include <xo/object2/number/IGCObject_DInteger.hpp>
 #include <xo/object2/Boolean.hpp>
-#include <xo/gc/GCObjectConversion.hpp>
 #include <xo/object2/number/GCObjectConversion_DFloat.hpp>
 #include <xo/object2/number/GCObjectConversion_DInteger.hpp>
+#include <xo/alloc2/GCObjectConversion.hpp>
 #include <xo/facet/facet.hpp>
 #include <cmath>