diff --git a/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp b/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp
index 6018a662..e7b65c34 100644
--- a/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp
+++ b/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp
@@ -57,7 +57,7 @@ namespace xo {
             /** move instance using allocator **/
             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;
+            static void forward_children(DGlobalEnv & self, obj<ACollector> gc) noexcept;
             ///@}
         };
 
diff --git a/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp b/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp
index f743e5cb..3e382bb0 100644
--- a/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp
+++ b/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp
@@ -57,7 +57,7 @@ namespace xo {
             /** move instance using allocator **/
             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;
+            static void forward_children(DSchematikaParser & self, obj<ACollector> gc) noexcept;
             ///@}
         };
 
diff --git a/src/reader2/facet/IGCObject_DGlobalEnv.cpp b/src/reader2/facet/IGCObject_DGlobalEnv.cpp
index b31cadf6..19af8f25 100644
--- a/src/reader2/facet/IGCObject_DGlobalEnv.cpp
+++ b/src/reader2/facet/IGCObject_DGlobalEnv.cpp
@@ -27,9 +27,9 @@ namespace xo {
             return self.shallow_move(gc);
         }
         auto
-        IGCObject_DGlobalEnv::forward_children(DGlobalEnv & self, obj<ACollector> gc) noexcept -> size_type
+        IGCObject_DGlobalEnv::forward_children(DGlobalEnv & self, obj<ACollector> gc) noexcept -> void
         {
-            return self.forward_children(gc);
+            self.forward_children(gc);
         }
 
     } /*namespace scm*/
diff --git a/src/reader2/facet/IGCObject_DSchematikaParser.cpp b/src/reader2/facet/IGCObject_DSchematikaParser.cpp
index 72c9d0e2..16ce2b5e 100644
--- a/src/reader2/facet/IGCObject_DSchematikaParser.cpp
+++ b/src/reader2/facet/IGCObject_DSchematikaParser.cpp
@@ -27,9 +27,9 @@ namespace xo {
             return self.shallow_move(gc);
         }
         auto
-        IGCObject_DSchematikaParser::forward_children(DSchematikaParser & self, obj<ACollector> gc) noexcept -> size_type
+        IGCObject_DSchematikaParser::forward_children(DSchematikaParser & self, obj<ACollector> gc) noexcept -> void
         {
-            return self.forward_children(gc);
+            self.forward_children(gc);
         }
 
     } /*namespace scm*/