diff --git a/xo-expression2/include/xo/expression2/DGlobalSymtab.hpp b/xo-expression2/include/xo/expression2/DGlobalSymtab.hpp
index 566d8981..8eec6d2e 100644
--- a/xo-expression2/include/xo/expression2/DGlobalSymtab.hpp
+++ b/xo-expression2/include/xo/expression2/DGlobalSymtab.hpp
@@ -47,6 +47,9 @@ namespace xo {
                                    obj<AAllocator> mm,
                                    const ArenaHashMapConfig & cfg);
 
+            /** non-trivial destructor for @ref map_ **/
+            ~DGlobalSymtab() = default;
+
             ///@}
             /** @defgroup scm-globalsymtab-access-methods access methods **/
             ///@{
diff --git a/xo-interpreter2/include/xo/interpreter2/VirtualSchematikaMachine.hpp b/xo-interpreter2/include/xo/interpreter2/VirtualSchematikaMachine.hpp
index 2cbd08e4..a34310ab 100644
--- a/xo-interpreter2/include/xo/interpreter2/VirtualSchematikaMachine.hpp
+++ b/xo-interpreter2/include/xo/interpreter2/VirtualSchematikaMachine.hpp
@@ -81,6 +81,11 @@ namespace xo {
             VirtualSchematikaMachine(const VsmConfig & config,
                                      obj<AAllocator> aux_mm);
 
+            /** non-trivial dtor because of @ref reader_
+             *  indirect dependency on DGlobalSymtab
+             **/
+            ~VirtualSchematikaMachine() = default;
+
             /** allocator for schematika data **/
             obj<AAllocator> allocator() const noexcept;
             /** allocator for runtime errors **/
diff --git a/xo-reader2/include/xo/reader2/ParserStateMachine.hpp b/xo-reader2/include/xo/reader2/ParserStateMachine.hpp
index 74a3e9bb..38cff2b8 100644
--- a/xo-reader2/include/xo/reader2/ParserStateMachine.hpp
+++ b/xo-reader2/include/xo/reader2/ParserStateMachine.hpp
@@ -57,6 +57,9 @@ namespace xo {
                                obj<AAllocator> expr_alloc,
                                obj<AAllocator> aux_alloc);
 
+            /** non-trivial dtor for @ref global_symtab_ **/
+            ~ParserStateMachine() = default;
+
             /** @defgroup scm-parserstatemachine-accessors accessor methods **/
             ///@{
 
@@ -313,12 +316,12 @@ namespace xo {
              **/
             DLocalSymtab * local_symtab_ = nullptr;
 
-#ifdef NOT_YET
             /** global symbol table.
              *  Toplevel definitions go here.
+             *
+             *  Uses mmap -> non-trivial destructor.
              **/
-            DGlobalSymtab * global_symtab_ = nullptr;
-#endif
+            dp<DGlobalSymtab> global_symtab_;
 
             /** current output from parser **/
             ParserResult result_;
diff --git a/xo-reader2/include/xo/reader2/SchematikaParser.hpp b/xo-reader2/include/xo/reader2/SchematikaParser.hpp
index 13cb18ee..ee86e6d5 100644
--- a/xo-reader2/include/xo/reader2/SchematikaParser.hpp
+++ b/xo-reader2/include/xo/reader2/SchematikaParser.hpp
@@ -178,6 +178,9 @@ namespace xo {
                              obj<AAllocator> aux_alloc,
                              bool debug_flag);
 
+            /** non-trivial dtor because of @ref psm_ **/
+            ~SchematikaParser() = default;
+
             /** scm-schematikaparser-access-methods **/
             ///@{
 
diff --git a/xo-reader2/include/xo/reader2/SchematikaReader.hpp b/xo-reader2/include/xo/reader2/SchematikaReader.hpp
index 6f2b325e..73b8166b 100644
--- a/xo-reader2/include/xo/reader2/SchematikaReader.hpp
+++ b/xo-reader2/include/xo/reader2/SchematikaReader.hpp
@@ -51,6 +51,9 @@ namespace xo {
                              obj<AAllocator> expr_alloc,
                              obj<AAllocator> fixed_alloc);
 
+            /** non-trivial dtor because of @p parser **/
+            ~SchematikaReader() = default;
+
             /** visit reader-owned memory pools; call visitor(info) for each.
              *  Specifically exclude expr_alloc, since we don't consider
              *  that reader-owned