diff --git a/idl/GCObject.json5 b/idl/GCObject.json5
index 8f7e071..0b4dfdf 100644
--- a/idl/GCObject.json5
+++ b/idl/GCObject.json5
@@ -62,7 +62,7 @@
             doc: ["move instance using allocator"],
             return_type: "Opaque",
             args:[
-                {type: "obj<AAllocator>", name: "mm"},
+                {type: "obj<ACollector>", name: "gc"},
             ],
             const: true,
             noexcept: true,
diff --git a/include/xo/alloc2/gc/AGCObject.hpp b/include/xo/alloc2/gc/AGCObject.hpp
index ee0703d..44c777e 100644
--- a/include/xo/alloc2/gc/AGCObject.hpp
+++ b/include/xo/alloc2/gc/AGCObject.hpp
@@ -67,7 +67,7 @@ public:
 
     // nonconst methods
     /** move instance using allocator **/
-    virtual Opaque shallow_move(Opaque data, obj<AAllocator> mm)  const  noexcept = 0;
+    virtual Opaque shallow_move(Opaque data, obj<ACollector> gc)  const  noexcept = 0;
     /** during GC: forward immdiate children **/
     virtual size_type forward_children(Opaque data, obj<ACollector> gc)  const  noexcept = 0;
     ///@}
diff --git a/include/xo/alloc2/gc/IGCObject_Any.hpp b/include/xo/alloc2/gc/IGCObject_Any.hpp
index 000c85f..25ff5db 100644
--- a/include/xo/alloc2/gc/IGCObject_Any.hpp
+++ b/include/xo/alloc2/gc/IGCObject_Any.hpp
@@ -64,7 +64,7 @@ namespace mm {
         [[noreturn]] size_type shallow_size(Copaque)  const  noexcept override { _fatal(); }
 
         // nonconst methods
-        [[noreturn]] Opaque shallow_move(Opaque, obj<AAllocator>)  const  noexcept override;
+        [[noreturn]] Opaque shallow_move(Opaque, obj<ACollector>)  const  noexcept override;
         [[noreturn]] size_type forward_children(Opaque, obj<ACollector>)  const  noexcept override;
 
         ///@}
diff --git a/include/xo/alloc2/gc/IGCObject_Xfer.hpp b/include/xo/alloc2/gc/IGCObject_Xfer.hpp
index 35e23a6..b311e6f 100644
--- a/include/xo/alloc2/gc/IGCObject_Xfer.hpp
+++ b/include/xo/alloc2/gc/IGCObject_Xfer.hpp
@@ -54,8 +54,8 @@ namespace mm {
         }
 
         // non-const methods
-        Opaque shallow_move(Opaque data, obj<AAllocator> mm)  const  noexcept override {
-            return I::shallow_move(_dcast(data), mm);
+        Opaque shallow_move(Opaque data, obj<ACollector> gc)  const  noexcept override {
+            return I::shallow_move(_dcast(data), gc);
         }
         size_type forward_children(Opaque data, obj<ACollector> gc)  const  noexcept override {
             return I::forward_children(_dcast(data), gc);
diff --git a/include/xo/alloc2/gc/RCollector.hpp b/include/xo/alloc2/gc/RCollector.hpp
index 6192c08..3bb2146 100644
--- a/include/xo/alloc2/gc/RCollector.hpp
+++ b/include/xo/alloc2/gc/RCollector.hpp
@@ -52,38 +52,38 @@ public:
     void * alloc_copy_for(const T * src) noexcept {
         return O::iface()->alloc_copy(O::data(), (std::byte *)const_cast<T *>(src));
     }
-    
+
     /** convenience template for move-constructible T (this is common) **/
     template <typename T>
-    void * std_copy_for(const T * src) noexcept {
+    T * std_copy_for(T * src) noexcept {
         void * mem = this->alloc_copy_for(src);
         if (mem) {
             return new (mem) T(std::move(*src));
         }
         return nullptr;
     }
-    
+
     /** forward faceted object pointer in place. Defined in GCObject.hpp to avoid #include cycle **/
     template <typename DRepr>
     void forward_inplace(obj<AGCObject,DRepr> * p_obj);
-    
+
     /** another convenience template for forwarding.
      *  Defined in RGCObject.hpp to avoid #include cycle.
     **/
     template <typename DRepr>
     void forward_inplace(DRepr ** pp_repr);
-    
+
     /** convenience template where pointer requires pivot **/
     template <typename AFacet, typename DRepr>
     requires (!std::is_same_v<AFacet, AGCObject>)
     void forward_pivot_inplace(obj<AFacet,DRepr> * p_obj);
-    
+
     /** add root @p p_root **/
     template<typename DRepr>
     void add_gc_root(obj<AGCObject, DRepr> * p_root) {
         O::iface()->add_gc_root_poly(O::data(), (obj<AGCObject> *)p_root);
     }
-    
+
     /** remove root @p p_root **/
     template <typename DRepr>
     void remove_gc_root(obj<AGCObject, DRepr> * p_root) {
diff --git a/include/xo/alloc2/gc/RGCObject.hpp b/include/xo/alloc2/gc/RGCObject.hpp
index 1839f83..673e6e0 100644
--- a/include/xo/alloc2/gc/RGCObject.hpp
+++ b/include/xo/alloc2/gc/RGCObject.hpp
@@ -60,8 +60,8 @@ public:
     }
 
     // non-const methods (still const in router!)
-    Opaque shallow_move(obj<AAllocator> mm)  noexcept {
-        return O::iface()->shallow_move(O::data(), mm);
+    Opaque shallow_move(obj<ACollector> gc)  noexcept {
+        return O::iface()->shallow_move(O::data(), gc);
     }
     size_type forward_children(obj<ACollector> gc)  noexcept {
         return O::iface()->forward_children(O::data(), gc);
diff --git a/src/alloc2/IGCObject_Any.cpp b/src/alloc2/IGCObject_Any.cpp
index c9b9329..a22df0f 100644
--- a/src/alloc2/IGCObject_Any.cpp
+++ b/src/alloc2/IGCObject_Any.cpp
@@ -36,7 +36,7 @@ IGCObject_Any::_valid
 // nonconst methods
 
 auto
-IGCObject_Any::shallow_move(Opaque, obj<AAllocator>)  const  noexcept -> Opaque
+IGCObject_Any::shallow_move(Opaque, obj<ACollector>)  const  noexcept -> Opaque
 {
     _fatal();
 }