diff --git a/include/xo/alloc2/alloc/IAllocator_Any.hpp b/include/xo/alloc2/alloc/IAllocator_Any.hpp
index 06e7e58..bc91fca 100644
--- a/include/xo/alloc2/alloc/IAllocator_Any.hpp
+++ b/include/xo/alloc2/alloc/IAllocator_Any.hpp
@@ -35,6 +35,8 @@ namespace xo {
 
             // builtin methods
             typeseq _typeseq() const noexcept  override { return s_typeseq; }
+
+            // LCOV_EXCL_START
             void _drop(Opaque) const noexcept override { _fatal(); }
 
             // const methods
@@ -58,9 +60,6 @@ namespace xo {
             [[noreturn]] value_type          alloc(Opaque, typeseq, std::size_t) const override { _fatal(); }
             [[noreturn]] value_type    super_alloc(Opaque, typeseq, std::size_t) const override { _fatal(); }
             [[noreturn]] value_type      sub_alloc(Opaque, std::size_t, bool) const override { _fatal(); }
-#ifdef OBSOLETE
-            [[noreturn]] value_type     alloc_copy(Opaque, value_type) const override { _fatal(); }
-#endif
             [[noreturn]] void                clear(Opaque) const override { _fatal(); }
             [[noreturn]] void   barrier_assign_aux(Opaque,
                                                    void *,
@@ -69,6 +68,7 @@ namespace xo {
 
         private:
             [[noreturn]] static void _fatal();
+            // LCOV_EXCL_STOP
 
         public:
             static typeseq s_typeseq;
diff --git a/include/xo/alloc2/arena/IAllocator_DArena.hpp b/include/xo/alloc2/arena/IAllocator_DArena.hpp
index 5a3ad8f..a178e5a 100644
--- a/include/xo/alloc2/arena/IAllocator_DArena.hpp
+++ b/include/xo/alloc2/arena/IAllocator_DArena.hpp
@@ -78,7 +78,7 @@ namespace xo {
                                            void * parent,
                                            AGCObject * lhs_iface, void ** lhs_data,
                                            AGCObject * rhs_iface, void * rhs_data);
-            static void destruct_data(DArena &);
+            //static void destruct_data(DArena &);
         };
 
 //        template <>
diff --git a/include/xo/alloc2/gc/RCollector.hpp b/include/xo/alloc2/gc/RCollector.hpp
index b7c54d4..2818957 100644
--- a/include/xo/alloc2/gc/RCollector.hpp
+++ b/include/xo/alloc2/gc/RCollector.hpp
@@ -52,7 +52,7 @@ public:
     void * alloc_copy_for(const T * src) noexcept {
         return O::iface()->alloc_copy(O::data(), (std::byte *)const_cast<T *>(src));
     }
-    
+
     /** convenience template for move-constructible T (this is common) **/
     template <typename T>
     T * std_move_for(T * src) noexcept {
@@ -62,28 +62,28 @@ public:
         }
         return nullptr;
     }
-    
+
     /** forward faceted object pointer in place. Defined in GCObject.hpp to avoid #include cycle **/
     template <typename DRepr>
     void forward_inplace(obj<AGCObject,DRepr> * p_obj);
-    
+
     /** another convenience template for forwarding.
      *  Defined in RGCObject.hpp to avoid #include cycle.
     **/
     template <typename DRepr>
     void forward_inplace(DRepr ** pp_repr);
-    
+
     /** convenience template where pointer requires pivot **/
     template <typename AFacet, typename DRepr>
     requires (!std::is_same_v<AFacet, AGCObject>)
     void forward_pivot_inplace(obj<AFacet,DRepr> * p_obj);
-    
+
     /** add root @p p_root **/
     template<typename DRepr>
     void add_gc_root(obj<AGCObject, DRepr> * p_root) {
         O::iface()->add_gc_root_poly(O::data(), (obj<AGCObject> *)p_root);
     }
-    
+
     /** remove root @p p_root **/
     template <typename DRepr>
     void remove_gc_root(obj<AGCObject, DRepr> * p_root) {
@@ -91,6 +91,7 @@ public:
     }
 
     // builtin methods
+    bool _has_null_vptr() const noexcept { return O::iface()->_has_null_vptr(); }
     typeseq _typeseq() const noexcept { return O::iface()->_typeseq(); }
     void _drop() const noexcept { O::iface()->_drop(O::data()); }
 
diff --git a/src/alloc2/IAllocator_Any.cpp b/src/alloc2/IAllocator_Any.cpp
index 813973c..d8b1aab 100644
--- a/src/alloc2/IAllocator_Any.cpp
+++ b/src/alloc2/IAllocator_Any.cpp
@@ -14,6 +14,7 @@ namespace xo {
 
     namespace mm {
 
+        // LCOV_EXCL_START
         void
         IAllocator_Any::_fatal()
         {
@@ -29,6 +30,7 @@ namespace xo {
 
             std::terminate();
         }
+        // LCOV_EXCL_STOP
 
         typeseq
         IAllocator_Any::s_typeseq = typeseq::id<DVariantPlaceholder>();
diff --git a/src/alloc2/IAllocator_DArena.cpp b/src/alloc2/IAllocator_DArena.cpp
index 3f205a9..ea60b69 100644
--- a/src/alloc2/IAllocator_DArena.cpp
+++ b/src/alloc2/IAllocator_DArena.cpp
@@ -173,11 +173,13 @@ namespace xo {
             *lhs_data = rhs_data;
         }
 
+#ifdef OBSOLETE
         void
         IAllocator_DArena::destruct_data(DArena & s)
         {
             s.~DArena();
         }
+#endif
     } /*namespace mm*/
 } /*namespace xo*/
 
diff --git a/utest/CMakeLists.txt b/utest/CMakeLists.txt
index af2d319..c885daa 100644
--- a/utest/CMakeLists.txt
+++ b/utest/CMakeLists.txt
@@ -6,6 +6,7 @@ set(UTEST_SRCS
     alloc2_utest_main.cpp
     objectmodel.test.cpp
     arena.test.cpp
+    IAllocator_Any.test.cpp
     DArenaIterator.test.cpp
 #    Collector.test.cpp
 #    DX1CollectorIterator.test.cpp
diff --git a/utest/IAllocator_Any.test.cpp b/utest/IAllocator_Any.test.cpp
new file mode 100644
index 0000000..5d23c6e
--- /dev/null
+++ b/utest/IAllocator_Any.test.cpp
@@ -0,0 +1,29 @@
+/** @file IAllocator_Any.test.cpp
+ *
+ *  @author Roland Conybeare, May 2026
+ **/
+
+#include <xo/alloc2/Allocator.hpp>
+#include <catch2/catch.hpp>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <signal.h>
+
+namespace xo {
+    using xo::mm::AAllocator;
+
+    namespace ut {
+
+        TEST_CASE("IAllocator_Any", "[alloc2][death]")
+        {
+            // null allocator
+            obj<AAllocator> alloc_any;
+
+            // NOTE: tried using a fork() strategy to verify termination,
+            //       but child process doesn't get measured by gcov
+        }
+
+    } /*namespace ut*/
+} /*namespace xo*/
+
+/* end IAllocator_Any.test.cpp */
diff --git a/utest/arena.test.cpp b/utest/arena.test.cpp
index 0a1c3e9..95077f6 100644
--- a/utest/arena.test.cpp
+++ b/utest/arena.test.cpp
@@ -97,6 +97,8 @@ namespace xo {
             //obj<AAllocator, DArena> a1o{&arena};
             auto a1o = with_facet<AAllocator>::mkobj(&arena);
 
+            REQUIRE(!a1o._has_null_vptr());
+
             REQUIRE(a1o);
             REQUIRE(a1o.iface() != nullptr);
             REQUIRE(a1o.data() != nullptr);
@@ -110,6 +112,12 @@ namespace xo {
             REQUIRE(a1o.size() == 0);
             REQUIRE(a1o.committed() == 0);
             REQUIRE(a1o.allocated() == 0);
+
+            a1o._drop();
+            {
+                REQUIRE(a1o.allocated() == 0);
+                REQUIRE(a1o.committed() == 0);
+            }
         }
 
         TEST_CASE("allocator-expand-1", "[alloc2][AAllocator]")
@@ -122,6 +130,8 @@ namespace xo {
             //obj<AAllocator, DArena> a1o{&arena};
             auto a1o = with_facet<AAllocator>::mkobj(&arena);
 
+            REQUIRE(!a1o._has_null_vptr());
+
             REQUIRE(a1o.available() == 0);
             REQUIRE(a1o.allocated() == 0);
 
@@ -141,6 +151,11 @@ namespace xo {
             REQUIRE(a1o.available() == a1o.committed());
             REQUIRE(a1o.allocated() == 0);
 
+            a1o._drop();
+            {
+                REQUIRE(a1o.allocated() == 0);
+                REQUIRE(a1o.committed() == 0);
+            }
         }
 
         TEST_CASE("allocator-alloc-1", "[alloc2][AAllocator]")
@@ -152,6 +167,8 @@ namespace xo {
             DArena arena = DArena::map(cfg);
             auto a1o = with_facet<AAllocator>::mkobj(&arena);
 
+            REQUIRE(!a1o._has_null_vptr());
+
             REQUIRE(a1o.reserved() >= cfg.size_);
             REQUIRE(a1o.committed() == 0);
             REQUIRE(a1o.available() == 0);
@@ -180,6 +197,12 @@ namespace xo {
             REQUIRE(a1o.allocated() <= a1o.committed());
             REQUIRE(a1o.allocated() + a1o.available() == a1o.committed());
             REQUIRE(a1o.committed() <= a1o.reserved());
+
+            a1o._drop();
+            {
+                REQUIRE(a1o.allocated() == 0);
+                REQUIRE(a1o.committed() == 0);
+            }
         }
 
         TEST_CASE("allocator-alloc-2", "[alloc2][Allocator]")
@@ -202,6 +225,8 @@ namespace xo {
             //obj<AAllocator, DArena> a1o{&arena};
             auto a1o = with_facet<AAllocator>::mkobj(&arena);
 
+            REQUIRE(!a1o._has_null_vptr());
+
             REQUIRE(a1o.reserved() >= cfg.size_);
             REQUIRE(a1o.committed() == 0);
             REQUIRE(a1o.available() == 0);
@@ -244,19 +269,26 @@ namespace xo {
             }
 
             a1o.clear();
+            {
+                // allocated size got reset
+                REQUIRE(a1o.allocated() == 0);
+                // committed size unchanged
+                REQUIRE(a1o.committed() == committed0_z);
+                REQUIRE(a1o.last_error().error_ == error::ok);
+                REQUIRE(a1o.last_error().error_seq_ == 0);
 
-            // allocated size got reset
-            REQUIRE(a1o.allocated() == 0);
-            // committed size unchanged
-            REQUIRE(a1o.committed() == committed0_z);
-            REQUIRE(a1o.last_error().error_ == error::ok);
-            REQUIRE(a1o.last_error().error_seq_ == 0);
+                // allocator no longer contains m0 (now points to unallocated but committed memory
+                // (not exposed via AAllocator!
+                // REQUIRE(a1o.contains_allocated(m0) == false);
 
-            // allocator no longer contains m0 (now points to unallocated but committed memory
-            // (not exposed via AAllocator!
-            // REQUIRE(a1o.contains_allocated(m0) == false);
+                REQUIRE(a1o.contains(m0));
+            }
 
-            REQUIRE(a1o.contains(m0));
+            a1o._drop();
+            {
+                REQUIRE(a1o.allocated() == 0);
+                REQUIRE(a1o.committed() == 0);
+            }
         }
 
         TEST_CASE("allocator-alloc-3", "[alloc2][Allocator]")
@@ -279,6 +311,8 @@ namespace xo {
             //obj<AAllocator, DArena> a1o{&arena};
             auto a1o = with_facet<AAllocator>::mkobj(&arena);
 
+            REQUIRE(!a1o._has_null_vptr());
+
             REQUIRE(a1o.reserved() >= cfg.size_);
             REQUIRE(a1o.committed() == 0);
             REQUIRE(a1o.available() == 0);
@@ -301,23 +335,30 @@ namespace xo {
             header_type* header = (header_type*)(m0 - sizeof(header_type));
             size_t pad = padding::with_padding(z0) - z0;
             byte * guard1 = m0 + z0 + pad;
+            {
+                REQUIRE(a1o.contains(guard0));
+                REQUIRE(a1o.contains(header));
+                REQUIRE(cfg.header_.size(*header) == padding::with_padding(z0));
+                //REQUIRE(((*header) & cfg.header_size_mask_) == padding::with_padding(z0));
 
-            REQUIRE(a1o.contains(guard0));
-            REQUIRE(a1o.contains(header));
-            REQUIRE(cfg.header_.size(*header) == padding::with_padding(z0));
-            //REQUIRE(((*header) & cfg.header_size_mask_) == padding::with_padding(z0));
+                REQUIRE(a1o.last_error().error_ == error::ok);
+                REQUIRE(a1o.last_error().error_seq_ == 0);
 
-            REQUIRE(a1o.last_error().error_ == error::ok);
-            REQUIRE(a1o.last_error().error_seq_ == 0);
+                REQUIRE(a1o.allocated() == (cfg.header_.guard_z_
+                                            + sizeof(header_type)
+                                            + z0
+                                            + pad
+                                            + cfg.header_.guard_z_));
+                REQUIRE(a1o.allocated() <= a1o.committed());
+                REQUIRE(a1o.allocated() + a1o.available() == a1o.committed());
+                REQUIRE(a1o.committed() <= a1o.reserved());
+            }
 
-            REQUIRE(a1o.allocated() == (cfg.header_.guard_z_
-                                        + sizeof(header_type)
-                                        + z0
-                                        + pad
-                                        + cfg.header_.guard_z_));
-            REQUIRE(a1o.allocated() <= a1o.committed());
-            REQUIRE(a1o.allocated() + a1o.available() == a1o.committed());
-            REQUIRE(a1o.committed() <= a1o.reserved());
+            a1o._drop();
+            {
+                REQUIRE(a1o.allocated() == 0);
+                REQUIRE(a1o.committed() == 0);
+            }
         }
 
         TEST_CASE("allocator-fail-1", "[alloc2][AAllocator]")
@@ -332,6 +373,8 @@ namespace xo {
 
             REQUIRE(cfg.size_ <= cfg.hugepage_z_);
 
+            REQUIRE(!a1o._has_null_vptr());
+
             REQUIRE(a1o.reserved() >= cfg.size_);
             REQUIRE(a1o.committed() == 0);
             REQUIRE(a1o.available() == 0);
@@ -339,17 +382,22 @@ namespace xo {
 
             size_t z0 = cfg.hugepage_z_ + 1;
             byte * m0 = a1o.alloc(typeseq::sentinel(), z0);
-
-            REQUIRE(!m0);
-
             AllocError err = a1o.last_error();
+            {
+                REQUIRE(!m0);
+                REQUIRE(err.error_ == error::reserve_exhausted);
+                REQUIRE(err.error_seq_ == 1);
+                REQUIRE(err.request_z_ >= z0);
+                REQUIRE(err.request_z_ < z0 + padding::c_alloc_alignment);
+                REQUIRE(err.committed_z_ == 0);
+                REQUIRE(err.reserved_z_ == arena.reserved());
+            }
 
-            REQUIRE(err.error_ == error::reserve_exhausted);
-            REQUIRE(err.error_seq_ == 1);
-            REQUIRE(err.request_z_ >= z0);
-            REQUIRE(err.request_z_ < z0 + padding::c_alloc_alignment);
-            REQUIRE(err.committed_z_ == 0);
-            REQUIRE(err.reserved_z_ == arena.reserved());
+            a1o._drop();
+            {
+                REQUIRE(a1o.allocated() == 0);
+                REQUIRE(a1o.committed() == 0);
+            }
         }
     } /*namespace ut*/
 } /*namespace xo*/