diff --git a/include/xo/procedure2/DPrimitive.hpp b/include/xo/procedure2/DPrimitive.hpp
index f602ebb..d55e01e 100644
--- a/include/xo/procedure2/DPrimitive.hpp
+++ b/include/xo/procedure2/DPrimitive.hpp
@@ -134,7 +134,7 @@ namespace xo {
             /** @defgroup scm-primitive-gcobject-facet **/
             ///@{
             std::size_t shallow_size() const noexcept;
-            Primitive * shallow_move(obj<AAllocator> mm) const noexcept;
+            Primitive * shallow_move(obj<ACollector> gc) noexcept;
             std::size_t forward_children(obj<ACollector> gc) noexcept;
             ///@}
 
@@ -198,14 +198,8 @@ namespace xo {
 
         template <typename Fn>
         Primitive<Fn> *
-        Primitive<Fn>::shallow_move(obj<AAllocator> mm) const noexcept {
-            void * mem = mm.alloc_copy((std::byte *)this);
-
-            if (mem) {
-                return new (mem) Primitive(*this);
-            }
-
-            return nullptr;
+        Primitive<Fn>::shallow_move(obj<ACollector> gc) noexcept {
+            return gc.std_copy_for(this);
         }
 
         template <typename Fn>
diff --git a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_0.hpp b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_0.hpp
index cecc298..53c073a 100644
--- a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_0.hpp
+++ b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_0.hpp
@@ -55,7 +55,7 @@ namespace xo {
 
             // non-const methods
             /** move instance using allocator **/
-            static Opaque shallow_move(DPrimitive_gco_0 & self, obj<AAllocator> mm) noexcept;
+            static Opaque shallow_move(DPrimitive_gco_0 & self, obj<ACollector> gc) noexcept;
             /** during GC: forward immdiate children **/
             static size_type forward_children(DPrimitive_gco_0 & self, obj<ACollector> gc) noexcept;
             ///@}
diff --git a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_1_gco.hpp b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_1_gco.hpp
index ac5c4f5..e2dd638 100644
--- a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_1_gco.hpp
+++ b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_1_gco.hpp
@@ -55,7 +55,7 @@ namespace xo {
 
             // non-const methods
             /** move instance using allocator **/
-            static Opaque shallow_move(DPrimitive_gco_1_gco & self, obj<AAllocator> mm) noexcept;
+            static Opaque shallow_move(DPrimitive_gco_1_gco & self, obj<ACollector> gc) noexcept;
             /** during GC: forward immdiate children **/
             static size_type forward_children(DPrimitive_gco_1_gco & self, obj<ACollector> gc) noexcept;
             ///@}
diff --git a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_dict_string.hpp b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_dict_string.hpp
index 772aabb..c21ab14 100644
--- a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_dict_string.hpp
+++ b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_dict_string.hpp
@@ -55,7 +55,7 @@ namespace xo {
 
             // non-const methods
             /** move instance using allocator **/
-            static Opaque shallow_move(DPrimitive_gco_2_dict_string & self, obj<AAllocator> mm) noexcept;
+            static Opaque shallow_move(DPrimitive_gco_2_dict_string & self, obj<ACollector> gc) noexcept;
             /** during GC: forward immdiate children **/
             static size_type forward_children(DPrimitive_gco_2_dict_string & self, obj<ACollector> gc) noexcept;
             ///@}
diff --git a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_gco_gco.hpp b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_gco_gco.hpp
index 266d1f4..b35e100 100644
--- a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_gco_gco.hpp
+++ b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_gco_gco.hpp
@@ -55,7 +55,7 @@ namespace xo {
 
             // non-const methods
             /** move instance using allocator **/
-            static Opaque shallow_move(DPrimitive_gco_2_gco_gco & self, obj<AAllocator> mm) noexcept;
+            static Opaque shallow_move(DPrimitive_gco_2_gco_gco & self, obj<ACollector> gc) noexcept;
             /** during GC: forward immdiate children **/
             static size_type forward_children(DPrimitive_gco_2_gco_gco & self, obj<ACollector> gc) noexcept;
             ///@}
diff --git a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_3_dict_string_gco.hpp b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_3_dict_string_gco.hpp
index 7abc136..d0e23e3 100644
--- a/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_3_dict_string_gco.hpp
+++ b/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_3_dict_string_gco.hpp
@@ -55,7 +55,7 @@ namespace xo {
 
             // non-const methods
             /** move instance using allocator **/
-            static Opaque shallow_move(DPrimitive_gco_3_dict_string_gco & self, obj<AAllocator> mm) noexcept;
+            static Opaque shallow_move(DPrimitive_gco_3_dict_string_gco & self, obj<ACollector> gc) noexcept;
             /** during GC: forward immdiate children **/
             static size_type forward_children(DPrimitive_gco_3_dict_string_gco & self, obj<ACollector> gc) noexcept;
             ///@}
diff --git a/src/procedure2/facet/IGCObject_DPrimitive_gco_0.cpp b/src/procedure2/facet/IGCObject_DPrimitive_gco_0.cpp
index 948d1d6..2e0198f 100644
--- a/src/procedure2/facet/IGCObject_DPrimitive_gco_0.cpp
+++ b/src/procedure2/facet/IGCObject_DPrimitive_gco_0.cpp
@@ -22,9 +22,9 @@ namespace xo {
         }
 
         auto
-        IGCObject_DPrimitive_gco_0::shallow_move(DPrimitive_gco_0 & self, obj<AAllocator> mm) noexcept -> Opaque
+        IGCObject_DPrimitive_gco_0::shallow_move(DPrimitive_gco_0 & self, obj<ACollector> gc) noexcept -> Opaque
         {
-            return self.shallow_move(mm);
+            return self.shallow_move(gc);
         }
         auto
         IGCObject_DPrimitive_gco_0::forward_children(DPrimitive_gco_0 & self, obj<ACollector> gc) noexcept -> size_type
diff --git a/src/procedure2/facet/IGCObject_DPrimitive_gco_1_gco.cpp b/src/procedure2/facet/IGCObject_DPrimitive_gco_1_gco.cpp
index b5c1754..2612c88 100644
--- a/src/procedure2/facet/IGCObject_DPrimitive_gco_1_gco.cpp
+++ b/src/procedure2/facet/IGCObject_DPrimitive_gco_1_gco.cpp
@@ -22,9 +22,9 @@ namespace xo {
         }
 
         auto
-        IGCObject_DPrimitive_gco_1_gco::shallow_move(DPrimitive_gco_1_gco & self, obj<AAllocator> mm) noexcept -> Opaque
+        IGCObject_DPrimitive_gco_1_gco::shallow_move(DPrimitive_gco_1_gco & self, obj<ACollector> gc) noexcept -> Opaque
         {
-            return self.shallow_move(mm);
+            return self.shallow_move(gc);
         }
         auto
         IGCObject_DPrimitive_gco_1_gco::forward_children(DPrimitive_gco_1_gco & self, obj<ACollector> gc) noexcept -> size_type
diff --git a/src/procedure2/facet/IGCObject_DPrimitive_gco_2_dict_string.cpp b/src/procedure2/facet/IGCObject_DPrimitive_gco_2_dict_string.cpp
index 7c58550..6173f6c 100644
--- a/src/procedure2/facet/IGCObject_DPrimitive_gco_2_dict_string.cpp
+++ b/src/procedure2/facet/IGCObject_DPrimitive_gco_2_dict_string.cpp
@@ -22,9 +22,9 @@ namespace xo {
         }
 
         auto
-        IGCObject_DPrimitive_gco_2_dict_string::shallow_move(DPrimitive_gco_2_dict_string & self, obj<AAllocator> mm) noexcept -> Opaque
+        IGCObject_DPrimitive_gco_2_dict_string::shallow_move(DPrimitive_gco_2_dict_string & self, obj<ACollector> gc) noexcept -> Opaque
         {
-            return self.shallow_move(mm);
+            return self.shallow_move(gc);
         }
         auto
         IGCObject_DPrimitive_gco_2_dict_string::forward_children(DPrimitive_gco_2_dict_string & self, obj<ACollector> gc) noexcept -> size_type
diff --git a/src/procedure2/facet/IGCObject_DPrimitive_gco_2_gco_gco.cpp b/src/procedure2/facet/IGCObject_DPrimitive_gco_2_gco_gco.cpp
index 347295b..ab7cc1b 100644
--- a/src/procedure2/facet/IGCObject_DPrimitive_gco_2_gco_gco.cpp
+++ b/src/procedure2/facet/IGCObject_DPrimitive_gco_2_gco_gco.cpp
@@ -22,9 +22,9 @@ namespace xo {
         }
 
         auto
-        IGCObject_DPrimitive_gco_2_gco_gco::shallow_move(DPrimitive_gco_2_gco_gco & self, obj<AAllocator> mm) noexcept -> Opaque
+        IGCObject_DPrimitive_gco_2_gco_gco::shallow_move(DPrimitive_gco_2_gco_gco & self, obj<ACollector> gc) noexcept -> Opaque
         {
-            return self.shallow_move(mm);
+            return self.shallow_move(gc);
         }
         auto
         IGCObject_DPrimitive_gco_2_gco_gco::forward_children(DPrimitive_gco_2_gco_gco & self, obj<ACollector> gc) noexcept -> size_type
diff --git a/src/procedure2/facet/IGCObject_DPrimitive_gco_3_dict_string_gco.cpp b/src/procedure2/facet/IGCObject_DPrimitive_gco_3_dict_string_gco.cpp
index 26a9f3f..4134581 100644
--- a/src/procedure2/facet/IGCObject_DPrimitive_gco_3_dict_string_gco.cpp
+++ b/src/procedure2/facet/IGCObject_DPrimitive_gco_3_dict_string_gco.cpp
@@ -22,9 +22,9 @@ namespace xo {
         }
 
         auto
-        IGCObject_DPrimitive_gco_3_dict_string_gco::shallow_move(DPrimitive_gco_3_dict_string_gco & self, obj<AAllocator> mm) noexcept -> Opaque
+        IGCObject_DPrimitive_gco_3_dict_string_gco::shallow_move(DPrimitive_gco_3_dict_string_gco & self, obj<ACollector> gc) noexcept -> Opaque
         {
-            return self.shallow_move(mm);
+            return self.shallow_move(gc);
         }
         auto
         IGCObject_DPrimitive_gco_3_dict_string_gco::forward_children(DPrimitive_gco_3_dict_string_gco & self, obj<ACollector> gc) noexcept -> size_type