diff --git a/include/xo/expression2/DConstant.hpp b/include/xo/expression2/DConstant.hpp
index 0c57f924..2c8b4a96 100644
--- a/include/xo/expression2/DConstant.hpp
+++ b/include/xo/expression2/DConstant.hpp
@@ -8,8 +8,8 @@
 #include "Expression.hpp"
 #include "TypeRef.hpp"
 #include "exprtype.hpp"
-#include <xo/gc/Collector.hpp>
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/Collector.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/reflect/TaggedPtr.hpp>
 
 namespace xo {
diff --git a/include/xo/expression2/DIfElseExpr.hpp b/include/xo/expression2/DIfElseExpr.hpp
index 3b7b07e2..0cf71332 100644
--- a/include/xo/expression2/DIfElseExpr.hpp
+++ b/include/xo/expression2/DIfElseExpr.hpp
@@ -8,7 +8,7 @@
 #include "Expression.hpp"
 #include "TypeRef.hpp"
 #include "exprtype.hpp"
-#include <xo/gc/Collector.hpp>
+#include <xo/alloc2/Collector.hpp>
 #include <xo/alloc2/Allocator.hpp>
 //#include <vector>
 #include <string>
diff --git a/include/xo/expression2/DUniqueString.hpp b/include/xo/expression2/DUniqueString.hpp
index 30655b45..e43624bd 100644
--- a/include/xo/expression2/DUniqueString.hpp
+++ b/include/xo/expression2/DUniqueString.hpp
@@ -1,5 +1,5 @@
 /** @file DUniqueString.hpp
-*
+ *
  *  @author Roland Conybeare, Jan 2026
  **/
 
@@ -69,12 +69,7 @@ namespace xo {
             /** compare unique strings: return n with {n<0, n=0, n>0}
              *  when @p lhs lexicographically {before, at, after} @p rhs
              **/
-            static int compare(const DUniqueString & lhs, const DUniqueString & rhs) {
-                if (&lhs == &rhs)
-                    return 0;
-
-                return DString::compare(*(lhs._text()), *(rhs._text()));
-            }
+            static int compare(const DUniqueString & lhs, const DUniqueString & rhs);
 
             std::size_t hash() const noexcept { return _text()->hash(); }
             operator std::string_view() const noexcept { return std::string_view(*_text()); }
@@ -124,14 +119,6 @@ namespace xo {
             ///@}
 
             friend class StringTable;
-
-        private:
-#ifdef NOPE
-            /** interned string.  Note stringtable memory distinct from gc memory,
-             *  so gc will not (and should not) traverse this pointer.
-             **/
-            const DString * text_ = nullptr;
-#endif
         };
 
         /* since unique: just compare addresses */
diff --git a/include/xo/expression2/define/IGCObject_DDefineExpr.hpp b/include/xo/expression2/define/IGCObject_DDefineExpr.hpp
index 216dd18b..321ce4e9 100644
--- a/include/xo/expression2/define/IGCObject_DDefineExpr.hpp
+++ b/include/xo/expression2/define/IGCObject_DDefineExpr.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DDefineExpr.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/detail/IGCObject_DApplyExpr.hpp b/include/xo/expression2/detail/IGCObject_DApplyExpr.hpp
index 10b08c10..f0bf15ff 100644
--- a/include/xo/expression2/detail/IGCObject_DApplyExpr.hpp
+++ b/include/xo/expression2/detail/IGCObject_DApplyExpr.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DApplyExpr.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/detail/IGCObject_DConstant.hpp b/include/xo/expression2/detail/IGCObject_DConstant.hpp
index 871f9c91..da593190 100644
--- a/include/xo/expression2/detail/IGCObject_DConstant.hpp
+++ b/include/xo/expression2/detail/IGCObject_DConstant.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DConstant.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/detail/IGCObject_DIfElseExpr.hpp b/include/xo/expression2/detail/IGCObject_DIfElseExpr.hpp
index 6a47d9b8..20cea34f 100644
--- a/include/xo/expression2/detail/IGCObject_DIfElseExpr.hpp
+++ b/include/xo/expression2/detail/IGCObject_DIfElseExpr.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DIfElseExpr.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/detail/IGCObject_DLambdaExpr.hpp b/include/xo/expression2/detail/IGCObject_DLambdaExpr.hpp
index 7d1ba5b0..2f4e72e0 100644
--- a/include/xo/expression2/detail/IGCObject_DLambdaExpr.hpp
+++ b/include/xo/expression2/detail/IGCObject_DLambdaExpr.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DLambdaExpr.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/detail/IGCObject_DSequenceExpr.hpp b/include/xo/expression2/detail/IGCObject_DSequenceExpr.hpp
index 1f6b8deb..51009ecd 100644
--- a/include/xo/expression2/detail/IGCObject_DSequenceExpr.hpp
+++ b/include/xo/expression2/detail/IGCObject_DSequenceExpr.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DSequenceExpr.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/detail/IGCObject_DUniqueString.hpp b/include/xo/expression2/detail/IGCObject_DUniqueString.hpp
index 398e3eed..9968d6da 100644
--- a/include/xo/expression2/detail/IGCObject_DUniqueString.hpp
+++ b/include/xo/expression2/detail/IGCObject_DUniqueString.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DUniqueString.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/detail/IGCObject_DVarRef.hpp b/include/xo/expression2/detail/IGCObject_DVarRef.hpp
index e991ebb8..487e2832 100644
--- a/include/xo/expression2/detail/IGCObject_DVarRef.hpp
+++ b/include/xo/expression2/detail/IGCObject_DVarRef.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DVarRef.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/detail/IGCObject_DVariable.hpp b/include/xo/expression2/detail/IGCObject_DVariable.hpp
index 242f335f..4728746f 100644
--- a/include/xo/expression2/detail/IGCObject_DVariable.hpp
+++ b/include/xo/expression2/detail/IGCObject_DVariable.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DVariable.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/expression2_register_facets.hpp b/include/xo/expression2/expression2_register_facets.hpp
index 95feeea5..1a559c72 100644
--- a/include/xo/expression2/expression2_register_facets.hpp
+++ b/include/xo/expression2/expression2_register_facets.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include <xo/gc/Collector.hpp>
+#include <xo/alloc2/Collector.hpp>
 
 namespace xo {
     namespace scm {
diff --git a/include/xo/expression2/expression2_register_types.hpp b/include/xo/expression2/expression2_register_types.hpp
index 6c7cc959..58105eed 100644
--- a/include/xo/expression2/expression2_register_types.hpp
+++ b/include/xo/expression2/expression2_register_types.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include <xo/gc/Collector.hpp>
+#include <xo/alloc2/Collector.hpp>
 
 namespace xo {
     namespace scm {
diff --git a/include/xo/expression2/symtab/IGCObject_DGlobalSymtab.hpp b/include/xo/expression2/symtab/IGCObject_DGlobalSymtab.hpp
index 92149015..f136b513 100644
--- a/include/xo/expression2/symtab/IGCObject_DGlobalSymtab.hpp
+++ b/include/xo/expression2/symtab/IGCObject_DGlobalSymtab.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DGlobalSymtab.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/include/xo/expression2/symtab/IGCObject_DLocalSymtab.hpp b/include/xo/expression2/symtab/IGCObject_DLocalSymtab.hpp
index 94b9e279..cc770261 100644
--- a/include/xo/expression2/symtab/IGCObject_DLocalSymtab.hpp
+++ b/include/xo/expression2/symtab/IGCObject_DLocalSymtab.hpp
@@ -14,7 +14,7 @@
 #pragma once
 
 #include "GCObject.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include "DLocalSymtab.hpp"
 
@@ -64,4 +64,4 @@ namespace xo {
     } /*namespace scm*/
 } /*namespace xo*/
 
-/* end */
\ No newline at end of file
+/* end */
diff --git a/src/expression2/DDefineExpr.cpp b/src/expression2/DDefineExpr.cpp
index aee6ccf9..aa1ea105 100644
--- a/src/expression2/DDefineExpr.cpp
+++ b/src/expression2/DDefineExpr.cpp
@@ -5,7 +5,7 @@
 
 #include "DDefineExpr.hpp"
 #include "Variable.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/gc/PolyForwarderUtil.hpp>
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
diff --git a/src/expression2/DGlobalSymtab.cpp b/src/expression2/DGlobalSymtab.cpp
index 38809a38..95db6b26 100644
--- a/src/expression2/DGlobalSymtab.cpp
+++ b/src/expression2/DGlobalSymtab.cpp
@@ -8,7 +8,7 @@
 #include <xo/expression2/Expression.hpp>
 #include <xo/expression2/Variable.hpp>
 #include <xo/object2/Array.hpp>
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/facet/FacetRegistry.hpp>
 #include <xo/indentlog/scope.hpp>
 
diff --git a/src/expression2/DIfElseExpr.cpp b/src/expression2/DIfElseExpr.cpp
index 6a0b053c..649a2482 100644
--- a/src/expression2/DIfElseExpr.cpp
+++ b/src/expression2/DIfElseExpr.cpp
@@ -5,7 +5,7 @@
 
 #include "DIfElseExpr.hpp"
 #include "detail/IExpression_DIfElseExpr.hpp"
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
 #include <xo/reflectutil/typeseq.hpp>
diff --git a/src/expression2/DSequenceExpr.cpp b/src/expression2/DSequenceExpr.cpp
index 22b097fb..fdc73b8e 100644
--- a/src/expression2/DSequenceExpr.cpp
+++ b/src/expression2/DSequenceExpr.cpp
@@ -7,7 +7,7 @@
 #include "detail/IExpression_DSequenceExpr.hpp"
 #include <xo/object2/array/IGCObject_DArray.hpp>
 #include <xo/object2/array/IPrintable_DArray.hpp>
-#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/GCObject.hpp>
 #include <xo/alloc2/Allocator.hpp>
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
diff --git a/src/expression2/DUniqueString.cpp b/src/expression2/DUniqueString.cpp
index c0fa26db..98a7b33c 100644
--- a/src/expression2/DUniqueString.cpp
+++ b/src/expression2/DUniqueString.cpp
@@ -4,6 +4,7 @@
  **/
 
 #include "DUniqueString.hpp"
+#include "DString.hpp"
 #include <xo/arena/padding.hpp>
 #include <xo/indentlog/scope.hpp>
 #include <cstring>
@@ -13,6 +14,15 @@ namespace xo {
     using xo::facet::typeseq;
 
     namespace scm {
+        int
+        DUniqueString::compare(const DUniqueString & lhs, const DUniqueString & rhs)
+        {
+            if (&lhs == &rhs)
+                return 0;
+
+            return DString::compare(*(lhs._text()), *(rhs._text()));
+        }
+
         DString *
         DUniqueString::_text() const noexcept
         {
diff --git a/src/expression2/DVariable.cpp b/src/expression2/DVariable.cpp
index ac051387..8fc201a5 100644
--- a/src/expression2/DVariable.cpp
+++ b/src/expression2/DVariable.cpp
@@ -5,8 +5,8 @@
 
 #include "DVariable.hpp"
 #include "exprtype.hpp"
-#include <cstddef>
 #include <xo/indentlog/print/quoted.hpp>
+#include <cstddef>
 
 namespace xo {
     using xo::mm::ACollector;
diff --git a/src/expression2/expression2_register_facets.cpp b/src/expression2/expression2_register_facets.cpp
index 82bff638..a9edbc20 100644
--- a/src/expression2/expression2_register_facets.cpp
+++ b/src/expression2/expression2_register_facets.cpp
@@ -25,7 +25,7 @@
 #include <xo/expression2/GlobalSymtab.hpp>
 #include <xo/expression2/LocalSymtab.hpp>
 
-#include <xo/gc/detail/AGCObject.hpp>
+#include <xo/alloc2/gc/AGCObject.hpp>
 #include <xo/printable2/detail/APrintable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
 #include <xo/indentlog/scope.hpp>