diff --git a/include/xo/stringtable2/string/IGCObject_DString.hpp b/include/xo/stringtable2/string/IGCObject_DString.hpp
index c4a71a5..9607666 100644
--- a/include/xo/stringtable2/string/IGCObject_DString.hpp
+++ b/include/xo/stringtable2/string/IGCObject_DString.hpp
@@ -57,7 +57,7 @@ namespace xo {
             /** move instance using allocator **/
             static Opaque shallow_move(DString & self, obj<ACollector> gc) noexcept;
             /** during GC: forward immdiate children **/
-            static size_type forward_children(DString & self, obj<ACollector> gc) noexcept;
+            static void forward_children(DString & self, obj<ACollector> gc) noexcept;
             ///@}
         };
 
diff --git a/include/xo/stringtable2/uniquestring/IGCObject_DUniqueString.hpp b/include/xo/stringtable2/uniquestring/IGCObject_DUniqueString.hpp
index 27bc825..0a71251 100644
--- a/include/xo/stringtable2/uniquestring/IGCObject_DUniqueString.hpp
+++ b/include/xo/stringtable2/uniquestring/IGCObject_DUniqueString.hpp
@@ -57,7 +57,7 @@ namespace xo {
             /** move instance using allocator **/
             static Opaque shallow_move(DUniqueString & self, obj<ACollector> gc) noexcept;
             /** during GC: forward immdiate children **/
-            static size_type forward_children(DUniqueString & self, obj<ACollector> gc) noexcept;
+            static void forward_children(DUniqueString & self, obj<ACollector> gc) noexcept;
             ///@}
         };
 
diff --git a/src/stringtable2/IGCObject_DString.cpp b/src/stringtable2/IGCObject_DString.cpp
index 01fc837..e6e7fbb 100644
--- a/src/stringtable2/IGCObject_DString.cpp
+++ b/src/stringtable2/IGCObject_DString.cpp
@@ -27,9 +27,9 @@ namespace xo {
             return self.shallow_move(gc);
         }
         auto
-        IGCObject_DString::forward_children(DString & self, obj<ACollector> gc) noexcept -> size_type
+        IGCObject_DString::forward_children(DString & self, obj<ACollector> gc) noexcept -> void
         {
-            return self.forward_children(gc);
+            self.forward_children(gc);
         }
 
     } /*namespace scm*/
diff --git a/src/stringtable2/IGCObject_DUniqueString.cpp b/src/stringtable2/IGCObject_DUniqueString.cpp
index 82e7c65..e865913 100644
--- a/src/stringtable2/IGCObject_DUniqueString.cpp
+++ b/src/stringtable2/IGCObject_DUniqueString.cpp
@@ -27,9 +27,9 @@ namespace xo {
             return self.shallow_move(gc);
         }
         auto
-        IGCObject_DUniqueString::forward_children(DUniqueString & self, obj<ACollector> gc) noexcept -> size_type
+        IGCObject_DUniqueString::forward_children(DUniqueString & self, obj<ACollector> gc) noexcept -> void
         {
-            return self.forward_children(gc);
+            self.forward_children(gc);
         }
 
     } /*namespace scm*/