diff --git a/include/xo/expression2/DUniqueString.hpp b/include/xo/expression2/DUniqueString.hpp
index e43624bd..9f56a9c9 100644
--- a/include/xo/expression2/DUniqueString.hpp
+++ b/include/xo/expression2/DUniqueString.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include <xo/object2/DString.hpp>
+#include <xo/stringtable2/DString.hpp>
 
 namespace xo {
     namespace scm {
diff --git a/src/expression2/init_expression2.cpp b/src/expression2/init_expression2.cpp
index 1ee5ec9e..0d107316 100644
--- a/src/expression2/init_expression2.cpp
+++ b/src/expression2/init_expression2.cpp
@@ -8,7 +8,7 @@
 #include "expression2_register_types.hpp"
 
 #include <xo/procedure2/init_procedure2.hpp>
-#include <xo/gc/CollectorTypeRegistry.hpp>
+#include <xo/alloc2/CollectorTypeRegistry.hpp>
 
 namespace xo {
     using xo::scm::expression2_register_facets;
diff --git a/utest/DApplyExpr.test.cpp b/utest/DApplyExpr.test.cpp
index 1b922333..17b3dca6 100644
--- a/utest/DApplyExpr.test.cpp
+++ b/utest/DApplyExpr.test.cpp
@@ -20,10 +20,10 @@
 #include <xo/object2/DFloat.hpp>
 #include <xo/object2/number/IGCObject_DFloat.hpp>
 
-#include <xo/gc/CollectorTypeRegistry.hpp>
-#include <xo/gc/DX1Collector.hpp>
-#include <xo/gc/detail/IAllocator_DX1Collector.hpp>
-#include <xo/gc/detail/ICollector_DX1Collector.hpp>
+#include <xo/alloc2/CollectorTypeRegistry.hpp>
+#include <xo/gc/X1Collector.hpp>
+//#include <xo/gc/detail/IAllocator_DX1Collector.hpp>
+//#include <xo/gc/detail/ICollector_DX1Collector.hpp>
 
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
diff --git a/utest/DConstant.test.cpp b/utest/DConstant.test.cpp
index fd8e9b1b..a45d39d8 100644
--- a/utest/DConstant.test.cpp
+++ b/utest/DConstant.test.cpp
@@ -13,10 +13,8 @@
 #include <xo/object2/number/IGCObject_DFloat.hpp>
 #include <xo/object2/number/IGCObject_DInteger.hpp>
 
-#include <xo/gc/CollectorTypeRegistry.hpp>
-#include <xo/gc/DX1Collector.hpp>
-#include <xo/gc/detail/IAllocator_DX1Collector.hpp>
-#include <xo/gc/detail/ICollector_DX1Collector.hpp>
+#include <xo/alloc2/CollectorTypeRegistry.hpp>
+#include <xo/gc/X1Collector.hpp>
 
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
diff --git a/utest/DDefineExpr.test.cpp b/utest/DDefineExpr.test.cpp
index 5f78891d..648af0f4 100644
--- a/utest/DDefineExpr.test.cpp
+++ b/utest/DDefineExpr.test.cpp
@@ -14,10 +14,10 @@
 #include <xo/object2/DFloat.hpp>
 #include <xo/object2/number/IGCObject_DFloat.hpp>
 
-#include <xo/gc/CollectorTypeRegistry.hpp>
-#include <xo/gc/DX1Collector.hpp>
-#include <xo/gc/detail/IAllocator_DX1Collector.hpp>
-#include <xo/gc/detail/ICollector_DX1Collector.hpp>
+#include <xo/alloc2/CollectorTypeRegistry.hpp>
+#include <xo/gc/X1Collector.hpp>
+//#include <xo/gc/detail/IAllocator_DX1Collector.hpp>
+//#include <xo/gc/detail/ICollector_DX1Collector.hpp>
 
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
diff --git a/utest/DIfElseExpr.test.cpp b/utest/DIfElseExpr.test.cpp
index 2dee2f26..4a7dcf70 100644
--- a/utest/DIfElseExpr.test.cpp
+++ b/utest/DIfElseExpr.test.cpp
@@ -15,10 +15,10 @@
 #include <xo/object2/number/IGCObject_DFloat.hpp>
 #include <xo/object2/boolean/IGCObject_DBoolean.hpp>
 
-#include <xo/gc/CollectorTypeRegistry.hpp>
-#include <xo/gc/DX1Collector.hpp>
-#include <xo/gc/detail/IAllocator_DX1Collector.hpp>
-#include <xo/gc/detail/ICollector_DX1Collector.hpp>
+#include <xo/alloc2/CollectorTypeRegistry.hpp>
+#include <xo/gc/X1Collector.hpp>
+//#include <xo/gc/detail/IAllocator_DX1Collector.hpp>
+//#include <xo/gc/detail/ICollector_DX1Collector.hpp>
 
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
diff --git a/utest/DVariable.test.cpp b/utest/DVariable.test.cpp
index 9c26a7c4..51e80a33 100644
--- a/utest/DVariable.test.cpp
+++ b/utest/DVariable.test.cpp
@@ -9,10 +9,8 @@
 #include <xo/expression2/detail/IPrintable_DVariable.hpp>
 #include <xo/expression2/StringTable.hpp>
 
-#include <xo/gc/CollectorTypeRegistry.hpp>
-#include <xo/gc/DX1Collector.hpp>
-#include <xo/gc/detail/IAllocator_DX1Collector.hpp>
-#include <xo/gc/detail/ICollector_DX1Collector.hpp>
+#include <xo/gc/X1Collector.hpp>
+#include <xo/alloc2/CollectorTypeRegistry.hpp>
 
 #include <xo/printable2/Printable.hpp>
 #include <xo/facet/FacetRegistry.hpp>
diff --git a/utest/X1Collector.test.cpp b/utest/X1Collector.test.cpp
index b872d877..08fb5ca9 100644
--- a/utest/X1Collector.test.cpp
+++ b/utest/X1Collector.test.cpp
@@ -12,14 +12,10 @@
 #include <xo/object2/DFloat.hpp>
 #include <xo/object2/DInteger.hpp>
 #include <xo/object2/DList.hpp>
-#include <xo/object2/DString.hpp>
-
-#include <xo/gc/CollectorTypeRegistry.hpp>
-#include <xo/gc/DX1Collector.hpp>
-
-#include <xo/gc/detail/IAllocator_DX1Collector.hpp>
-#include <xo/gc/detail/ICollector_DX1Collector.hpp>
+#include <xo/stringtable2/DString.hpp>
 
+#include <xo/gc/X1Collector.hpp>
+#include <xo/alloc2/CollectorTypeRegistry.hpp>
 #include <xo/subsys/Subsystem.hpp>
 
 #include <catch2/catch.hpp>