diff --git a/luprex/core/badmem.sh b/luprex/core/badmem.sh
index e21ba3d2..10964558 100755
--- a/luprex/core/badmem.sh
+++ b/luprex/core/badmem.sh
@@ -9,8 +9,6 @@ grep std::unordered_set cpp/*
 grep std::deque cpp/*
 grep std::ostringstream cpp/*
 grep std::ostream cpp/*
-grep std::unique_ptr cpp/*
-grep std::shared_ptr cpp/*
 
 grep std::cerr cpp/*
 grep std::cout cpp/*
diff --git a/luprex/core/cpp/animqueue.hpp b/luprex/core/cpp/animqueue.hpp
index d41499b4..03f4420c 100644
--- a/luprex/core/cpp/animqueue.hpp
+++ b/luprex/core/cpp/animqueue.hpp
@@ -57,7 +57,7 @@
 #include <cassert>
 #include <ostream>
 
-class AnimStep {
+class AnimStep : public eng::nevernew {
     friend class AnimQueue;
 public:
     enum {
@@ -166,7 +166,7 @@ private:
 };
 
 
-class AnimQueue {
+class AnimQueue : public eng::nevernew {
 public:
     // World type determines whether versions increment or autozero
     AnimQueue(util::WorldType wt);
diff --git a/luprex/core/cpp/debugcollector.hpp b/luprex/core/cpp/debugcollector.hpp
index 8376e394..947f90d6 100644
--- a/luprex/core/cpp/debugcollector.hpp
+++ b/luprex/core/cpp/debugcollector.hpp
@@ -8,7 +8,7 @@
 #include <ostream>
 #include <memory>
 
-class DebugCollector {
+class DebugCollector : public eng::nevernew {
 private:
     // At any given time, the stringstream may contain one
     // extra line that hasn't yet been appended to the list of lines.
@@ -33,7 +33,7 @@ public:
     friend class DebugBlock;
 };
 
-class DebugBlock {
+class DebugBlock : public eng::nevernew {
 private:
     DebugCollector *dbc_;
     int n_regular_;
diff --git a/luprex/core/cpp/drivenengine.hpp b/luprex/core/cpp/drivenengine.hpp
index d86ef3f1..4cb4d014 100644
--- a/luprex/core/cpp/drivenengine.hpp
+++ b/luprex/core/cpp/drivenengine.hpp
@@ -106,7 +106,7 @@ class DrivenEngine;
 using UniqueDrivenEngine = std::unique_ptr<DrivenEngine>;
 using DrivenEngineMaker = UniqueDrivenEngine (*)();
 
-class Channel {
+class Channel : public eng::opnew {
 public:
     // Get the buffers associated with this channel.
     //
@@ -190,7 +190,7 @@ private:
 
 using SharedChannel = std::shared_ptr<Channel>;
 
-class DrivenEngine {
+class DrivenEngine : public eng::opnew {
 public:
     //////////////////////////////////////////////////////////////
     //
diff --git a/luprex/core/cpp/eng-malloc.hpp b/luprex/core/cpp/eng-malloc.hpp
index a622139e..929e1981 100644
--- a/luprex/core/cpp/eng-malloc.hpp
+++ b/luprex/core/cpp/eng-malloc.hpp
@@ -13,27 +13,27 @@
 // In order to get all engine data structures into the eng::malloc heap, you
 // need to jump through quite a few hoops:
 //
-// * When using STL classes, you need to use the 'eng' variant of those classes:
+// * When writing a class, always derive from eng::opnew.  This adds a
+//   custom operator new to your class, which causes your class to be
+//   allocated using eng::malloc.
 //
-//   - eng::string instead of std::string (include "wrap-string.hpp")
-//   - eng::vector instead of std::vector (include "wrap-vector.hpp")
-//   - eng::map    instead of std::map    (include "wrap-map.hpp")
-//   - etc.
+// * When using STL containers, you need to use the eng variant:
+//   eng::map, eng::set, eng::vector, eng::unordered_map, eng::unordered_set,
+//   and eng::deque.  These classes derive from eng::opnew, and they also
+//   use eng::malloc for their internal nodes.
 //
-//   These eng classes allocate memory using eng::malloc instead of malloc.
-//
-// * All your classes must derive from eng::opnew.  This adds a custom operator
-//   new and operator delete to your class, which allocate using eng::malloc.
-//
-// * Use eng::make_shared and eng::make_unique instead of std::make_shared and
-//   std::make_unique.
+// * Use eng::string instead of std::string.  Use eng::ostringstream
+//   instead of std::ostringstream.
 //
 // * Simple classes like std::pair, std::string_view, std::less, std::hash, and
-//   so forth don't allocate memory.  Those classes are not wrapped.  There is
-//   no eng::pair, eng::less, etc.
+//   so forth are not wrapped.  Do not use operator new or delete on
+//   these classes.
+//
+// * Instead of std::make_shared, use eng::make_shared.  You need this
+//   because std::make_shared doesn't respect your custom operator new.
 //
 // * Be aware that most C++ streams use the system malloc heap, and there's no
-//   way to change that.   Fortunately, eng::ostringstream uses the dlmalloc
+//   way to change that.   Fortunately, eng::ostringstream uses the eng::malloc
 //   heap.
 //
 // * Failing to jump through all these hoops won't break your code in any
@@ -46,6 +46,7 @@
 
 #include <cstddef>
 #include <memory>
+#include <cassert>
 
 namespace eng {
 #ifdef __linux__
@@ -126,21 +127,60 @@ namespace eng {
         {
             return ::eng::free(p);
         }
+
+        void *operator new[](size_t size)
+        {
+            return ::eng::malloc(size);
+        }
+
+        void operator delete[](void *p, size_t size)
+        {
+            return ::eng::free(p);
+        }
     };
 } // namespace eng
 
+// eng::nevernew.  A class containing private operator new and
+// operator delete, making it impossible to 'new' the class.
+namespace eng {
+    class nevernew {
+    private:
+        void *operator new(size_t size)
+        {
+            assert(false && "not supposed to 'new' this class");
+            return NULL;
+        }
+
+        void operator delete(void *p, size_t size)
+        {
+            assert(false && "not supposed to 'delete' this class");
+        }
+
+        void *operator new[](size_t size)
+        {
+            assert(false && "not supposed to 'new' this class");
+            return NULL;
+        }
+
+        void operator delete[](void *p, size_t size)
+        {
+            assert(false && "not supposed to 'delete' this class");
+        }
+    };
+} // namespace eng
+
+
 // eng::make_shared allocates shared objects using eng::malloc.
 namespace eng {
     template<class T, class... Args>
     inline ::std::shared_ptr<T> make_shared(Args&&... args) {
-        static eng::allocator<T> alloc;
-        return std::allocate_shared<T>(alloc, args...);
+        return std::allocate_shared<T>(eng::allocator<T>(), args...);
     }
-}
+} // namespace eng
 
-// eng::make_unique doesn't do anything different than std::make_unique:
-// they both use operator new and delete.  You must
-// derive from eng::opnew to change operator new and delete.
+// eng::make_unique doesn't do anything different than std::make_unique: they
+// both use operator new and delete.  You must derive from eng::opnew to change
+// operator new and delete.
 namespace eng {
     template<class T, class... Args>
     inline ::std::unique_ptr<T> make_unique(Args&&... args) {
diff --git a/luprex/core/cpp/gui.hpp b/luprex/core/cpp/gui.hpp
index 103e50b3..85987321 100644
--- a/luprex/core/cpp/gui.hpp
+++ b/luprex/core/cpp/gui.hpp
@@ -8,7 +8,7 @@
 #include "luastack.hpp"
 #include "streambuffer.hpp"
 
-class GuiElt {
+class GuiElt : public eng::nevernew {
     friend class Gui;
 public:
     enum Type {
@@ -27,7 +27,7 @@ public:
     const eng::string &label() const { return label_; }
 };
 
-class Gui {
+class Gui : public eng::nevernew {
 public:
     using EltVec = eng::vector<GuiElt>;
 private:
diff --git a/luprex/core/cpp/idalloc.hpp b/luprex/core/cpp/idalloc.hpp
index 2b861e25..ff32a411 100644
--- a/luprex/core/cpp/idalloc.hpp
+++ b/luprex/core/cpp/idalloc.hpp
@@ -75,7 +75,7 @@
 #include <cstdint>
 #include <ostream>
 
-class IdGlobalPool {
+class IdGlobalPool : public eng::nevernew {
 public:
     // Construct and destroy global pools.  Note that after constructing
     // a global pool, it is generally also necessary to initialize it
@@ -119,7 +119,7 @@ private:
     friend int unittests_idalloc(lua_State *L);
 };
 
-class IdPlayerPool {
+class IdPlayerPool : public eng::nevernew {
 public:
     // Construct a player pool.
     //
diff --git a/luprex/core/cpp/invocation.hpp b/luprex/core/cpp/invocation.hpp
index 648561fe..49737950 100644
--- a/luprex/core/cpp/invocation.hpp
+++ b/luprex/core/cpp/invocation.hpp
@@ -16,7 +16,7 @@ public:
     void deserialize(StreamBuffer *sb);
 };
 
-class Invocation {
+class Invocation : public eng::nevernew {
 public:
     enum Kind {
         KIND_INVALID,
diff --git a/luprex/core/cpp/luaconsole.hpp b/luprex/core/cpp/luaconsole.hpp
index e26004bf..5476684f 100644
--- a/luprex/core/cpp/luaconsole.hpp
+++ b/luprex/core/cpp/luaconsole.hpp
@@ -47,7 +47,7 @@
 
 #include "luastack.hpp"
 
-class LuaConsole {
+class LuaConsole : public eng::nevernew {
 public:
     using StringVec = eng::vector<eng::string>;
 
diff --git a/luprex/core/cpp/luasnap.hpp b/luprex/core/cpp/luasnap.hpp
index 10592f59..0f152ef3 100644
--- a/luprex/core/cpp/luasnap.hpp
+++ b/luprex/core/cpp/luasnap.hpp
@@ -17,7 +17,7 @@
 #include "streambuffer.hpp"
 #include "luastack.hpp"
 
-class LuaSnap {
+class LuaSnap : public eng::nevernew {
 private:
     lua_State *state_;
     
diff --git a/luprex/core/cpp/luastack.hpp b/luprex/core/cpp/luastack.hpp
index 49696f8b..ace53ac3 100644
--- a/luprex/core/cpp/luastack.hpp
+++ b/luprex/core/cpp/luastack.hpp
@@ -163,7 +163,7 @@ extern "C" {
 #include "eris.h"
 }
 
-class LuaSlot {
+class LuaSlot : public eng::nevernew {
 protected:
     int index_;
 private:
@@ -226,7 +226,7 @@ int LuaTypeTagValue(lua_State *L) { return 0; }
 #define LUA_TT_GLOBALDB      22
 #define LUA_TT_CLASS         23
 
-class LuaStack {
+class LuaStack : public eng::nevernew {
 private:
     int narg_;
     int ngap_;
@@ -470,7 +470,7 @@ public:
 };
 
 
-class LuaFunctionReg {
+class LuaFunctionReg : public eng::nevernew {
 private:
     const char *name_;
     const char *args_;
diff --git a/luprex/core/cpp/planemap.hpp b/luprex/core/cpp/planemap.hpp
index 1573e006..bc7a71d6 100644
--- a/luprex/core/cpp/planemap.hpp
+++ b/luprex/core/cpp/planemap.hpp
@@ -83,7 +83,7 @@
 
 class PlaneMap;
 
-class PlaneItem {
+class PlaneItem : public eng::nevernew {
     friend class PlaneMap;
 
 private:
@@ -112,7 +112,7 @@ public:
     void set_xyz(float x, float y, float z) { set_pos(plane_, x, y, z); }
 };
 
-class PlaneMap {
+class PlaneMap : public eng::nevernew  {
     friend class PlaneItem;
 private:
     using EltVec = eng::vector<PlaneItem *>;
diff --git a/luprex/core/cpp/printbuffer.hpp b/luprex/core/cpp/printbuffer.hpp
index a98849e2..3d98634a 100644
--- a/luprex/core/cpp/printbuffer.hpp
+++ b/luprex/core/cpp/printbuffer.hpp
@@ -89,7 +89,7 @@
 
 struct PrintBufferCore;
 
-class PrintBuffer : public eng::opnew {
+class PrintBuffer : public eng::nevernew {
 private:
     PrintBufferCore *core_;
 
@@ -138,7 +138,7 @@ public:
 };
 
 
-class PrintChanneler : public eng::opnew {
+class PrintChanneler : public eng::nevernew {
 private:
     int64_t line_;
 public:
diff --git a/luprex/core/cpp/sched.hpp b/luprex/core/cpp/sched.hpp
index f11aa8a3..9af31c28 100644
--- a/luprex/core/cpp/sched.hpp
+++ b/luprex/core/cpp/sched.hpp
@@ -7,7 +7,7 @@
 
 #include <cstdint>
 
-class SchedEntry {
+class SchedEntry : public eng::nevernew  {
 private:
     friend class Schedule;
     int64_t clock_;
@@ -30,7 +30,7 @@ public:
     eng::string debug_string() const;
 };
 
-class Schedule {
+class Schedule : public eng::nevernew  {
 private:
     eng::set<SchedEntry> schedule_;
 public:
diff --git a/luprex/core/cpp/source.hpp b/luprex/core/cpp/source.hpp
index 60186ba3..6e1ed175 100644
--- a/luprex/core/cpp/source.hpp
+++ b/luprex/core/cpp/source.hpp
@@ -127,7 +127,7 @@
 #include "streambuffer.hpp"
 #include "debugcollector.hpp"
 
-class SourceDB {
+class SourceDB : public eng::nevernew  {
 private:
     lua_State *lua_state_;
 
diff --git a/luprex/core/cpp/streambuffer.cpp b/luprex/core/cpp/streambuffer.cpp
index bda56942..2019c2d5 100644
--- a/luprex/core/cpp/streambuffer.cpp
+++ b/luprex/core/cpp/streambuffer.cpp
@@ -490,7 +490,7 @@ void *StreamBuffer::lua_reader_ud(int64_t size) {
     return this;
 }
 
-class StreamBufferWriter : public std::streambuf {
+class StreamBufferWriter : public std::streambuf, public eng::opnew {
 private:
     StreamBuffer *target_;
 public:
@@ -504,7 +504,7 @@ public:
     }
 };
 
-class StreamBufferOStream : public std::ostream {
+class StreamBufferOStream : public std::ostream, public eng::opnew {
 private:
     StreamBufferWriter writer_;
 public:
diff --git a/luprex/core/cpp/streambuffer.hpp b/luprex/core/cpp/streambuffer.hpp
index 0238b5fe..378946ee 100644
--- a/luprex/core/cpp/streambuffer.hpp
+++ b/luprex/core/cpp/streambuffer.hpp
@@ -222,7 +222,7 @@
 #include "luastack.hpp"
 #include "util.hpp"
 
-class StreamException
+class StreamException : public eng::nevernew
 {
 public:
     virtual char const *what() const { return "General stream exception"; }
@@ -240,7 +240,7 @@ public:
     virtual char const *what() const { return "Stream contained invalid data"; }
 };
 
-class StreamBuffer {
+class StreamBuffer : public eng::nevernew {
 public:    
     // Construct an empty buffer.
     StreamBuffer();
diff --git a/luprex/core/cpp/world.hpp b/luprex/core/cpp/world.hpp
index 75c9b622..2154dbc8 100644
--- a/luprex/core/cpp/world.hpp
+++ b/luprex/core/cpp/world.hpp
@@ -24,7 +24,7 @@
 
 class World;
 
-class Tangible {
+class Tangible : public eng::opnew {
 private:
     friend class World;
 
@@ -90,7 +90,7 @@ public:
 
 using UniqueTangible = std::unique_ptr<Tangible>;
 
-class World {
+class World : public eng::opnew {
 public:
     using IdVector = util::IdVector;
     using TanVector = eng::vector<const Tangible*>;
diff --git a/luprex/core/wrap/wrap-deque.hpp b/luprex/core/wrap/wrap-deque.hpp
index 238fc0dd..6648864e 100644
--- a/luprex/core/wrap/wrap-deque.hpp
+++ b/luprex/core/wrap/wrap-deque.hpp
@@ -6,7 +6,9 @@
 
 namespace eng {
 template<class T>
-using deque = std::deque<T, eng::allocator<T>>;
+class deque : public std::deque<T, eng::allocator<T>>, public eng::opnew {
+    using std::deque<T, eng::allocator<T>>::deque;
+};
 } // namespace eng
 
 #endif // WRAP_DEQUE_HPP
diff --git a/luprex/core/wrap/wrap-map.hpp b/luprex/core/wrap/wrap-map.hpp
index 10905294..0077eca5 100644
--- a/luprex/core/wrap/wrap-map.hpp
+++ b/luprex/core/wrap/wrap-map.hpp
@@ -6,7 +6,9 @@
 
 namespace eng {
 template<class K, class V, class C=std::less<K>>
-using map = std::map<K, V, C, eng::allocator<std::pair<const K, V>>>;
+class map : public std::map<K, V, C, eng::allocator<std::pair<const K, V>>>, eng::opnew {
+    using std::map<K, V, C, eng::allocator<std::pair<const K, V>>>::map;
+};
 } // namespace eng
 
 #endif // WRAP_MAP_HPP
diff --git a/luprex/core/wrap/wrap-set.hpp b/luprex/core/wrap/wrap-set.hpp
index 8beee51d..dba5a388 100644
--- a/luprex/core/wrap/wrap-set.hpp
+++ b/luprex/core/wrap/wrap-set.hpp
@@ -6,7 +6,9 @@
 
 namespace eng {
 template<class K, class C=std::less<K>>
-using set = std::set<K, C, eng::allocator<K>>;
+class set : public std::set<K, C, eng::allocator<K>>, public eng::opnew {
+    using std::set<K, C, eng::allocator<K>>::set;
+};
 } // namespace eng
 
 #endif // WRAP_SET_HPP
diff --git a/luprex/core/wrap/wrap-sstream.hpp b/luprex/core/wrap/wrap-sstream.hpp
index 60ed91b5..785dfcbe 100644
--- a/luprex/core/wrap/wrap-sstream.hpp
+++ b/luprex/core/wrap/wrap-sstream.hpp
@@ -2,11 +2,16 @@
 #define WRAP_SSTREAM_HPP
 
 #include "eng-malloc.hpp"
+#include "wrap-string.hpp"
 #include <sstream>
+#include <string_view>
 
 namespace eng {
 template<class C, class T=std::char_traits<C>>
-using basic_ostringstream = std::basic_ostringstream<C, T, eng::allocator<C>>;
+class basic_ostringstream : public std::basic_ostringstream<C, T, eng::allocator<C>>, public eng::opnew {
+    using underlying = std::basic_ostringstream<C, T, eng::allocator<C>>;
+    using underlying::basic_ostringstream;
+};
 using ostringstream = basic_ostringstream<char>;
 } // namespace eng
 
diff --git a/luprex/core/wrap/wrap-unordered-map.hpp b/luprex/core/wrap/wrap-unordered-map.hpp
index 0a3ecd23..5b187f41 100644
--- a/luprex/core/wrap/wrap-unordered-map.hpp
+++ b/luprex/core/wrap/wrap-unordered-map.hpp
@@ -6,7 +6,9 @@
 
 namespace eng {
 template<class K, class V, class H=std::hash<K>, class E=std::equal_to<K>>
-using unordered_map = std::unordered_map<K, V, H, E, eng::allocator<std::pair<const K, V>>>;
+class unordered_map : public std::unordered_map<K, V, H, E, eng::allocator<std::pair<const K, V>>>, public eng::opnew {
+    using std::unordered_map<K, V, H, E, eng::allocator<std::pair<const K, V>>>::unordered_map;
+};
 } // namespace eng
 
 #endif // WRAP_UNORDERED_MAP_HPP
diff --git a/luprex/core/wrap/wrap-unordered-set.hpp b/luprex/core/wrap/wrap-unordered-set.hpp
index 8854b006..08640258 100644
--- a/luprex/core/wrap/wrap-unordered-set.hpp
+++ b/luprex/core/wrap/wrap-unordered-set.hpp
@@ -6,7 +6,9 @@
 
 namespace eng {
 template<class K, class H=std::hash<K>, class E=std::equal_to<K>>
-using unordered_set = std::unordered_set<K, H, E, eng::allocator<K>>;
+class unordered_set : public std::unordered_set<K, H, E, eng::allocator<K>>, public eng::opnew {
+    using std::unordered_set<K, H, E, eng::allocator<K>>::unordered_set;
+};
 } // namespace eng
 
 #endif // WRAP_UNORDERED_SET_HPP
diff --git a/luprex/core/wrap/wrap-vector.hpp b/luprex/core/wrap/wrap-vector.hpp
index a9cb254b..30a273d0 100644
--- a/luprex/core/wrap/wrap-vector.hpp
+++ b/luprex/core/wrap/wrap-vector.hpp
@@ -6,7 +6,9 @@
 
 namespace eng {
 template<class T>
-using vector = std::vector<T, eng::allocator<T>>;
+class vector : public std::vector<T, eng::allocator<T>>, public eng::opnew {
+    using std::vector<T, eng::allocator<T>>::vector;
+};
 } // namespace eng
 
 #endif // WRAP_VECTOR_HPP