diff --git a/include/xo/reader2/DGlobalEnv.hpp b/include/xo/reader2/DGlobalEnv.hpp
index 0c1536ee..96cd5771 100644
--- a/include/xo/reader2/DGlobalEnv.hpp
+++ b/include/xo/reader2/DGlobalEnv.hpp
@@ -71,7 +71,7 @@ namespace xo {
             ///@{
 
             std::size_t shallow_size() const noexcept;
-            DGlobalEnv * shallow_move(obj<AAllocator> mm) noexcept;
+            DGlobalEnv * shallow_move(obj<ACollector> gc) noexcept;
             std::size_t forward_children(obj<ACollector> gc) noexcept;
 
             ///@}
diff --git a/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp b/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp
index f8ff90b7..6018a662 100644
--- a/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp
+++ b/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp
@@ -55,7 +55,7 @@ namespace xo {
 
             // non-const methods
             /** move instance using allocator **/
-            static Opaque shallow_move(DGlobalEnv & self, obj<AAllocator> mm) noexcept;
+            static Opaque shallow_move(DGlobalEnv & self, obj<ACollector> gc) noexcept;
             /** during GC: forward immdiate children **/
             static size_type forward_children(DGlobalEnv & self, obj<ACollector> gc) noexcept;
             ///@}
diff --git a/include/xo/reader2/parser/DSchematikaParser.hpp b/include/xo/reader2/parser/DSchematikaParser.hpp
index da6862ab..07c85e4f 100644
--- a/include/xo/reader2/parser/DSchematikaParser.hpp
+++ b/include/xo/reader2/parser/DSchematikaParser.hpp
@@ -294,7 +294,7 @@ namespace xo {
 
             std::size_t shallow_size() const noexcept;
             /** not implemented (SchematikaParser not designed to be copyable) **/
-            DSchematikaParser * shallow_move(obj<AAllocator> mm) const noexcept;
+            DSchematikaParser * shallow_move(obj<ACollector> gc) noexcept;
             /** forward gc-aware children **/
             std::size_t forward_children(obj<ACollector> gc) noexcept;
 
diff --git a/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp b/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp
index e6fc39d9..f743e5cb 100644
--- a/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp
+++ b/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp
@@ -55,7 +55,7 @@ namespace xo {
 
             // non-const methods
             /** move instance using allocator **/
-            static Opaque shallow_move(DSchematikaParser & self, obj<AAllocator> mm) noexcept;
+            static Opaque shallow_move(DSchematikaParser & self, obj<ACollector> gc) noexcept;
             /** during GC: forward immdiate children **/
             static size_type forward_children(DSchematikaParser & self, obj<ACollector> gc) noexcept;
             ///@}
diff --git a/src/reader2/DGlobalEnv.cpp b/src/reader2/DGlobalEnv.cpp
index 17a86798..243fc8d6 100644
--- a/src/reader2/DGlobalEnv.cpp
+++ b/src/reader2/DGlobalEnv.cpp
@@ -114,9 +114,9 @@ namespace xo {
         }
 
         DGlobalEnv *
-        DGlobalEnv::shallow_move(obj<AAllocator> mm) noexcept
+        DGlobalEnv::shallow_move(obj<ACollector> gc) noexcept
         {
-            return mm.std_copy_for<DGlobalEnv>(this);
+            return gc.std_copy_for<DGlobalEnv>(this);
         }
 
         std::size_t
diff --git a/src/reader2/DSchematikaParser.cpp b/src/reader2/DSchematikaParser.cpp
index f26fe62a..35edc124 100644
--- a/src/reader2/DSchematikaParser.cpp
+++ b/src/reader2/DSchematikaParser.cpp
@@ -191,10 +191,13 @@ namespace xo {
         }
 
         DSchematikaParser *
-        DSchematikaParser::shallow_move(obj<AAllocator> mm) const noexcept
+        DSchematikaParser::shallow_move(obj<ACollector> gc) noexcept
         {
-            (void)mm;
+            (void)gc;
 
+            /** TODO: may be feasible to use gc.std_copy_for(this)
+             *  if/when DSchematikaParser is moveable
+             **/
             assert(false);
             return nullptr;
         }
diff --git a/src/reader2/facet/IGCObject_DGlobalEnv.cpp b/src/reader2/facet/IGCObject_DGlobalEnv.cpp
index f8edbb58..b31cadf6 100644
--- a/src/reader2/facet/IGCObject_DGlobalEnv.cpp
+++ b/src/reader2/facet/IGCObject_DGlobalEnv.cpp
@@ -22,9 +22,9 @@ namespace xo {
         }
 
         auto
-        IGCObject_DGlobalEnv::shallow_move(DGlobalEnv & self, obj<AAllocator> mm) noexcept -> Opaque
+        IGCObject_DGlobalEnv::shallow_move(DGlobalEnv & self, obj<ACollector> gc) noexcept -> Opaque
         {
-            return self.shallow_move(mm);
+            return self.shallow_move(gc);
         }
         auto
         IGCObject_DGlobalEnv::forward_children(DGlobalEnv & self, obj<ACollector> gc) noexcept -> size_type
diff --git a/src/reader2/facet/IGCObject_DSchematikaParser.cpp b/src/reader2/facet/IGCObject_DSchematikaParser.cpp
index 8ba2349c..72c9d0e2 100644
--- a/src/reader2/facet/IGCObject_DSchematikaParser.cpp
+++ b/src/reader2/facet/IGCObject_DSchematikaParser.cpp
@@ -22,9 +22,9 @@ namespace xo {
         }
 
         auto
-        IGCObject_DSchematikaParser::shallow_move(DSchematikaParser & self, obj<AAllocator> mm) noexcept -> Opaque
+        IGCObject_DSchematikaParser::shallow_move(DSchematikaParser & self, obj<ACollector> gc) noexcept -> Opaque
         {
-            return self.shallow_move(mm);
+            return self.shallow_move(gc);
         }
         auto
         IGCObject_DSchematikaParser::forward_children(DSchematikaParser & self, obj<ACollector> gc) noexcept -> size_type