diff --git a/include/xo/alloc/GC.hpp b/include/xo/alloc/GC.hpp
index 092f2f36..be2ff071 100644
--- a/include/xo/alloc/GC.hpp
+++ b/include/xo/alloc/GC.hpp
@@ -318,7 +318,8 @@ namespace xo {
              *  @param rhs.     new target for @p *lhs
              **/
             virtual void assign_member(IObject * parent, IObject ** lhs, IObject* rhs) final override;
-
+            /** evacuate @p *lhs and replace with forwarding pointer **/
+            virtual void forward_inplace(IObject ** lhs) final override;
             /** during GC check for source objects owned by GC.
              *  See Object::_shallow_move.
              **/
diff --git a/src/alloc/GC.cpp b/src/alloc/GC.cpp
index ca2506d9..40234bf3 100644
--- a/src/alloc/GC.cpp
+++ b/src/alloc/GC.cpp
@@ -568,6 +568,12 @@ namespace xo {
             }
         }
 
+        void
+        GC::forward_inplace(IObject ** lhs)
+        {
+            Object::_forward_inplace(lhs, this);
+        }
+
         bool
         GC::check_owned(IObject * src) const
         {
diff --git a/src/alloc/Object.cpp b/src/alloc/Object.cpp
index 82583a0a..75abec14 100644
--- a/src/alloc/Object.cpp
+++ b/src/alloc/Object.cpp
@@ -24,7 +24,8 @@ namespace xo {
     Object::mm = nullptr;
 
     IObject *
-    Object::_forward(IObject * src, gc::IAlloc * gc)
+    Object::_forward(IObject * src,
+                     gc::IAlloc * gc)
     {
         if (!src)
             return src;