diff --git a/include/xo/stringtable2/DUniqueString.hpp b/include/xo/stringtable2/DUniqueString.hpp
index c939f61..71427c4 100644
--- a/include/xo/stringtable2/DUniqueString.hpp
+++ b/include/xo/stringtable2/DUniqueString.hpp
@@ -88,13 +88,11 @@ namespace xo {
             /** @defgroup duniquestring-gcobject-methods gcobject facet methods **/
             ///@{
 
-            std::size_t shallow_size() const noexcept;
-
             /** clone unique string, using memory from allocator @p mm. **/
             DUniqueString * shallow_move(obj<ACollector> gc) noexcept;
 
             /** fixup child pointers (trivial for DUniqueString, no gc-owned children **/
-            std::size_t forward_children(obj<ACollector> gc) noexcept;
+            void forward_children(obj<ACollector> gc) noexcept;
 
             ///@}
 
diff --git a/src/stringtable2/DUniqueString.cpp b/src/stringtable2/DUniqueString.cpp
index 1d107f6..43e7f1c 100644
--- a/src/stringtable2/DUniqueString.cpp
+++ b/src/stringtable2/DUniqueString.cpp
@@ -81,12 +81,6 @@ namespace xo {
             return result;
         }
 
-        size_t
-        DUniqueString::shallow_size() const noexcept
-        {
-            return sizeof(DUniqueString);
-        }
-
         DUniqueString *
         DUniqueString::shallow_move(obj<ACollector> gc) noexcept
         {
@@ -114,10 +108,10 @@ namespace xo {
             return copy;
         }
 
-        size_t
+        void
         DUniqueString::forward_children(obj<ACollector>) noexcept
         {
-            return shallow_size();
+            // no-op
         }
     } /*namespace scm*/
 } /*namespace xo*/