diff --git a/luprex/cpp/core/world-difftab.cpp b/luprex/cpp/core/world-difftab.cpp
index 4cb716e6..b571b717 100644
--- a/luprex/cpp/core/world-difftab.cpp
+++ b/luprex/cpp/core/world-difftab.cpp
@@ -192,8 +192,8 @@ static bool diff_tables(LuaCoreStack &SLS0, LuaSlot stnmap, LuaSlot stab,
                         LuaCoreStack &MLS0, LuaSlot mtnmap, LuaSlot mtab,
                         bool cmeta, StreamBuffer *sb) {
     LuaVar skey, mkey, sval, mval, mnil;
-    LuaOldStack SLS(SLS0.state(), skey, sval);
-    LuaOldStack MLS(MLS0.state(), mkey, mval, mnil);
+    LuaExtStack SLS(SLS0.state(), skey, sval);
+    LuaExtStack MLS(MLS0.state(), mkey, mval, mnil);
     assert(MLS.istable(mtab));
     assert(SLS.istable(stab));
     MLS.set(mnil, LuaNil);
@@ -237,9 +237,6 @@ static bool diff_tables(LuaCoreStack &SLS0, LuaSlot stnmap, LuaSlot stab,
     }
 
     sb->overwrite_int32(wc, nupdates);
-
-    SLS.result();
-    MLS.result();
     return (nupdates > 0);
 }
 
@@ -323,7 +320,7 @@ static void set_transmitted_value(LuaCoreStack &LS, LuaSlot tangibles, LuaSlot n
 
 static void patch_table(LuaCoreStack &LS0, LuaSlot tangibles, LuaSlot ntmap, LuaSlot tab, StreamBuffer *sb, DebugCollector *dbc) {
     LuaVar key, val;
-    LuaOldStack LS(LS0.state(), key, val);
+    LuaExtStack LS(LS0.state(), key, val);
     int ndiffs = sb->read_int32();
     for (int i = 0; i < ndiffs; i++) {
         set_transmitted_value(LS, tangibles, ntmap, key, sb, "key=", dbc);
@@ -334,13 +331,12 @@ static void patch_table(LuaCoreStack &LS0, LuaSlot tangibles, LuaSlot ntmap, Lua
             LS.rawset(tab, key, val);
         }
     }
-    LS.result();
 }
 
 void World::patch_numbered_tables(StreamBuffer *sb, DebugCollector *dbc) {
     lua_State *L = state();
     LuaVar tangibles, ntmap, tab;
-    LuaOldStack LS(L, tangibles, ntmap, tab);
+    LuaExtStack LS(L, tangibles, ntmap, tab);
     LS.rawget(tangibles, LuaRegistry, "tangibles");
     LS.rawget(ntmap, LuaRegistry, "ntmap");
     assert(LS.istable(tangibles));
@@ -354,14 +350,13 @@ void World::patch_numbered_tables(StreamBuffer *sb, DebugCollector *dbc) {
         DebugHeader(dbc) << "Lua Table " << index << ":";
         patch_table(LS, tangibles, ntmap, tab, sb, dbc);
     }
-    LS.result();
 }
 
 void World::diff_numbered_tables(lua_State *master, StreamBuffer *sb) {
     lua_State *synch = state();
     LuaVar sntmap, mntmap, stnmap, mtnmap, stab, mtab;
-    LuaOldStack SLS(synch, sntmap, stnmap, stab);
-    LuaOldStack MLS(master, mntmap, mtnmap, mtab);
+    LuaExtStack SLS(synch, sntmap, stnmap, stab);
+    LuaExtStack MLS(master, mntmap, mtnmap, mtab);
     SLS.rawget(sntmap, LuaRegistry, "ntmap");
     MLS.rawget(mntmap, LuaRegistry, "ntmap");
     SLS.rawget(stnmap, LuaRegistry, "tnmap");
@@ -392,14 +387,12 @@ void World::diff_numbered_tables(lua_State *master, StreamBuffer *sb) {
         assert(lua_gettop(master) == m_top);
     }
     sb->overwrite_int32(write_count_after, nmodified);
-    SLS.result();
-    MLS.result();
 }
 
 void World::patch_tangible_databases(StreamBuffer *sb, DebugCollector *dbc) {
     lua_State *L = state();
     LuaVar tangibles, ntmap, tab;
-    LuaOldStack LS(L, tangibles, ntmap, tab);
+    LuaExtStack LS(L, tangibles, ntmap, tab);
     LS.rawget(tangibles, LuaRegistry, "tangibles");
     LS.rawget(ntmap, LuaRegistry, "ntmap");
     assert(LS.istable(tangibles));
@@ -413,14 +406,13 @@ void World::patch_tangible_databases(StreamBuffer *sb, DebugCollector *dbc) {
         DebugHeader(dbc) << "Tangible DB " << id << ":";
         patch_table(LS, tangibles, ntmap, tab, sb, dbc);
     }
-    LS.result();
 }
 
 void World::diff_tangible_databases(const IdVector &basis, lua_State *master, StreamBuffer *sb) {
     lua_State *synch = state();
     LuaVar stnmap, mtnmap, stangibles, mtangibles, stab, mtab;
-    LuaOldStack SLS(synch, stnmap, stangibles, stab);
-    LuaOldStack MLS(master, mtnmap, mtangibles, mtab);
+    LuaExtStack SLS(synch, stnmap, stangibles, stab);
+    LuaExtStack MLS(master, mtnmap, mtangibles, mtab);
     SLS.rawget(stnmap, LuaRegistry, "tnmap");
     MLS.rawget(mtnmap, LuaRegistry, "tnmap");
     SLS.rawget(stangibles, LuaRegistry, "tangibles");
@@ -447,15 +439,13 @@ void World::diff_tangible_databases(const IdVector &basis, lua_State *master, St
         assert(lua_gettop(master) == m_top);
     }
     sb->overwrite_int32(write_count_after, nmodified);
-    SLS.result();
-    MLS.result();
 }
 
 LuaDefine(table_diffcompare, "mtnmap,mtab,stnmap,stab", "for unit testing only") {
     LuaArg mtnmap, mtab, mstnmap, mstab;
     LuaRet dbgstring;
     LuaVar tthread;
-    LuaOldStack MLS(L, mtnmap, mtab, mstnmap, mstab, dbgstring, tthread);
+    LuaDefStack MLS(L, mtnmap, mtab, mstnmap, mstab, dbgstring, tthread);
     // Check the arguments.
     MLS.checktable(mtnmap, "mtnmap");
     MLS.checktable(mstnmap, "mstnmap");
@@ -470,7 +460,7 @@ LuaDefine(table_diffcompare, "mtnmap,mtab,stnmap,stab", "for unit testing only")
     lua_pushvalue(L, mstab.index());
     lua_xmove(L, synch, 2);
     LuaArg stnmap,stab;
-    LuaOldStack SLS(synch, stnmap, stab);
+    LuaDefStack SLS(synch, stnmap, stab);
 
     // Call tablecmp_diff.
     StreamBuffer sb;
@@ -485,7 +475,7 @@ LuaDefine(table_diffapply, "mtnmap,mtab,mstab", "for unit testing only") {
     LuaArg mtnmap, mtab, mstab;
     LuaRet eql, eqlstr, rtab;
     LuaVar tthread, tangibles, mntmap, key, val;
-    LuaOldStack MLS(L, mtnmap, mtab, mstab, eql, eqlstr, rtab, tthread, tangibles, mntmap, key, val);
+    LuaDefStack MLS(L, mtnmap, mtab, mstab, eql, eqlstr, rtab, tthread, tangibles, mntmap, key, val);
     // Check the arguments.
     MLS.checktable(mtnmap, "mtnmap");
     MLS.checktable(mtab, "mtab");
@@ -509,7 +499,7 @@ LuaDefine(table_diffapply, "mtnmap,mtab,mstab", "for unit testing only") {
     lua_pushvalue(L, mstab.index());
     lua_xmove(L, synch, 2);
     LuaArg stnmap, stab;
-    LuaOldStack SLS(synch, stnmap, stab);
+    LuaDefStack SLS(synch, stnmap, stab);
 
     // Call diff_tables and patch_tables
     StreamBuffer sb;
diff --git a/luprex/cpp/core/world-diffxmit.cpp b/luprex/cpp/core/world-diffxmit.cpp
index 99e979f8..f4d56ebf 100644
--- a/luprex/cpp/core/world-diffxmit.cpp
+++ b/luprex/cpp/core/world-diffxmit.cpp
@@ -224,7 +224,7 @@ void World::patch_tanclass(StreamBuffer *sb, DebugCollector *dbc) {
     DebugBlock dbb(dbc, "patch_tanclass");
     lua_State *L = state();
     LuaVar tangibles, tab, meta, sclass;
-    LuaOldStack LS(L, tangibles, tab, meta, sclass);
+    LuaExtStack LS(L, tangibles, tab, meta, sclass);
     LS.rawget(tangibles, LuaRegistry, "tangibles");
 
     int nmodified = sb->read_int32();
@@ -242,45 +242,44 @@ void World::patch_tanclass(StreamBuffer *sb, DebugCollector *dbc) {
             LS.rawset(meta, "__index", sclass);
         }
     }
-    LS.result();
 }
 
 void World::diff_tanclass(int64_t actor_id, World *master, StreamBuffer *xsb) {
     StreamBuffer tsb;
 
-    LuaVar stangibles, mtangibles, stab, mtab, smeta, mmeta, sclass, mclass;
-    LuaOldStack SLS(state(), stangibles, stab, smeta, sclass);
-    LuaOldStack MLS(master->state(), mtangibles, mtab, mmeta, mclass);
-    SLS.rawget(stangibles, LuaRegistry, "tangibles");
-    MLS.rawget(mtangibles, LuaRegistry, "tangibles");
+    {
+        LuaVar stangibles, mtangibles, stab, mtab, smeta, mmeta, sclass, mclass;
+        LuaExtStack SLS(state(), stangibles, stab, smeta, sclass);
+        LuaExtStack MLS(master->state(), mtangibles, mtab, mmeta, mclass);
+        SLS.rawget(stangibles, LuaRegistry, "tangibles");
+        MLS.rawget(mtangibles, LuaRegistry, "tangibles");
 
-    // Calculate the set of close tangibles.
-    // TODO: we've already calculated this in an earlier function. This is
-    // wasteful.
-    util::IdVector closetans =
-        master->get_near(actor_id, RadiusClose, true, false, true);
+        // Calculate the set of close tangibles.
+        // TODO: we've already calculated this in an earlier function. This is
+        // wasteful.
+        util::IdVector closetans =
+            master->get_near(actor_id, RadiusClose, true, false, true);
 
-    tsb.write_int32(0);
-    int write_count_after = tsb.total_writes();
-    int nmodified = 0;
-    for (int64_t id : closetans) {
-        MLS.rawget(mtab, mtangibles, id);
-        SLS.rawget(stab, stangibles, id);
-        MLS.getmetatable(mmeta, mtab);
-        SLS.getmetatable(smeta, stab);
-        MLS.rawget(mclass, mmeta, "__index");
-        SLS.rawget(sclass, smeta, "__index");
-        eng::string mname = MLS.classname(mclass);
-        eng::string sname = SLS.classname(sclass);
-        if (mname != sname) {
-            tsb.write_int64(id);
-            tsb.write_string(mname);
-            nmodified += 1;
+        tsb.write_int32(0);
+        int write_count_after = tsb.total_writes();
+        int nmodified = 0;
+        for (int64_t id : closetans) {
+            MLS.rawget(mtab, mtangibles, id);
+            SLS.rawget(stab, stangibles, id);
+            MLS.getmetatable(mmeta, mtab);
+            SLS.getmetatable(smeta, stab);
+            MLS.rawget(mclass, mmeta, "__index");
+            SLS.rawget(sclass, smeta, "__index");
+            eng::string mname = MLS.classname(mclass);
+            eng::string sname = SLS.classname(sclass);
+            if (mname != sname) {
+                tsb.write_int64(id);
+                tsb.write_string(mname);
+                nmodified += 1;
+            }
         }
+        tsb.overwrite_int32(write_count_after, nmodified);
     }
-    tsb.overwrite_int32(write_count_after, nmodified);
-    SLS.result();
-    MLS.result();
 
     // Forward to client, and apply to server-synchronous.
     tsb.copy_into(xsb);