diff --git a/include/xo/gc/GCObjectStore.hpp b/include/xo/gc/GCObjectStore.hpp
index 83aec4e..1191e17 100644
--- a/include/xo/gc/GCObjectStore.hpp
+++ b/include/xo/gc/GCObjectStore.hpp
@@ -49,7 +49,7 @@ namespace xo {
             /** lookup interface from type sequence
              *  (can use tseq = typeseq::id<T>() for type T)
              **/
-            const AGCObject * lookup_type(typeseq tseq) const noexcept;
+            AGCObject * lookup_type(typeseq tseq) const noexcept;
 
             /** generation to which pointer @p addr belongs, given role @p r;
              *  sentinel if not found in this collector
@@ -217,7 +217,7 @@ namespace xo {
              *  Shallow: does not traverse children
              **/
             void * _shallow_move(DX1Collector * gc,
-                                 const AGCObject * iface,
+                                 AGCObject * iface,
                                  void * from_src);
 
         private:
diff --git a/src/gc/GCObjectStore.cpp b/src/gc/GCObjectStore.cpp
index df897e3..9fb1449 100644
--- a/src/gc/GCObjectStore.cpp
+++ b/src/gc/GCObjectStore.cpp
@@ -110,7 +110,7 @@ namespace xo {
             return slot.is_occupied();
         }
 
-        const AGCObject *
+        AGCObject *
         GCObjectStore::lookup_type(typeseq tseq) const noexcept
         {
             scope log(XO_DEBUG(false));
@@ -846,7 +846,7 @@ namespace xo {
             GCMoveCheckpoint gray_lo_v = this->snap_move_checkpoint(upto);
 
             //obj<AAllocator, DX1Collector> alloc(this);
-            const AGCObject * iface = lookup_type(tseq);
+            AGCObject * iface = this->lookup_type(tseq);
 
             assert(iface->_has_null_vptr() == false);
 
@@ -861,7 +861,7 @@ namespace xo {
 
         void *
         GCObjectStore::_shallow_move(DX1Collector * gc,
-                                     const AGCObject * iface,
+                                     AGCObject * iface,
                                      void * from_src)
         {
             scope log(XO_DEBUG(config_.debug_flag_));