diff --git a/include/xo/alloc/GC.hpp b/include/xo/alloc/GC.hpp
index aeb918c9..092f2f36 100644
--- a/include/xo/alloc/GC.hpp
+++ b/include/xo/alloc/GC.hpp
@@ -144,9 +144,17 @@ namespace xo {
             using GcCopyCallbackSet = xo::fn::UpCallbackSet<GcCopyCallback>;
             using nanos = decltype(xo::qty::qty::nanosecond);
 
+            /** rebind is for typed allocators. since IAlloc is untyped,
+             *  we want degenerate version
+             **/
+            template <typename U>
+            struct rebind { using other = GC; };
+
         public:
             /** create new GC instance with configuration @p config **/
             explicit GC(const Config & config);
+            /** noncopyable **/
+            GC(const GC & other) = delete;
             virtual ~GC();
 
             /** create GC allocator.
diff --git a/include/xo/alloc/Object.hpp b/include/xo/alloc/Object.hpp
index 2c11ea9e..9681afab 100644
--- a/include/xo/alloc/Object.hpp
+++ b/include/xo/alloc/Object.hpp
@@ -141,19 +141,6 @@ namespace xo {
     std::ostream &
     operator<< (std::ostream & os, gp<Object> x);
 
-    /** @class Cpof
-     *  @brief argument to operator new used for garbage collector evacuation phase
-     *
-     *  Tag overloaded operator new to activate allocation policy based on location
-     *  in memory of source object.
-     **/
-    class Cpof {
-    public:
-        explicit Cpof(gc::IAlloc * mm, const Object * src) : mm_{mm}, src_{src} {}
-
-        gc::IAlloc * mm_ = nullptr;
-        const void * src_ = nullptr;
-    };
 } /*namespace xo*/
 
 void * operator new (std::size_t z, const xo::Cpof & copy);