diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,9 +2,19 @@
 
 `hslua-objectorientation` uses [PVP Versioning][1].
 
-## hslua-objectorientation 1.0.0
+## hslua-objectorientation 2.0.1
 
-Release pending.
+Release 2021-11-04.
+
+  - Excludes absent properties from `pairs`: Properties that are
+    optional and not present in a sum-type value are no longer
+    included in the iterator output produced by `pairs` (i.e., the
+    `__pairs` metamethod). Previously, the names of absent
+    properties were pushed with a `nil` value.
+
+## hslua-objectorientation 2.0.0
+
+Release 2021-10-21.
 
 - Published without warning.
 
diff --git a/cbits/hslobj.c b/cbits/hslobj.c
--- a/cbits/hslobj.c
+++ b/cbits/hslobj.c
@@ -98,8 +98,9 @@
    * list of properties is the second object. */
   for (int i = 1; i <= lua_rawlen(L, -2); i++) {
     lua_rawgeti(L, -2, i);
-    lua_gettable(L, -2);  /* get property */
+    int objtype = lua_gettable(L, -2);  /* get property */
     lua_remove(L, -2);    /* remove previous object */
+    if (!objtype) break;  /* abort if this property of the alias is absent */
   }
   return 1;
 }
diff --git a/hslua-objectorientation.cabal b/hslua-objectorientation.cabal
--- a/hslua-objectorientation.cabal
+++ b/hslua-objectorientation.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.2
 name:                hslua-objectorientation
-version:             2.0.0
+version:             2.0.1
 synopsis:            Object orientation tools for HsLua
 description:         Expose Haskell objects to Lua with an object oriented
                      interface.
@@ -35,7 +35,7 @@
                      , containers        >= 0.5.9  && < 0.7
                      , exceptions        >= 0.8    && < 0.11
                      , hslua-core        >= 2.0    && < 2.1
-                     , hslua-marshalling >= 2.0    && < 2.1
+                     , hslua-marshalling >= 2.0.1  && < 2.1
                      , mtl               >= 2.2    && < 2.3
                      , text              >= 1.0    && < 1.3
   ghc-options:         -Wall
diff --git a/src/HsLua/ObjectOrientation.hs b/src/HsLua/ObjectOrientation.hs
--- a/src/HsLua/ObjectOrientation.hs
+++ b/src/HsLua/ObjectOrientation.hs
@@ -313,7 +313,9 @@
         MemberProperty name prop -> do
           pushName name
           getresults <- propertyGet prop obj
-          return $ getresults + 1
+          if getresults == 0
+            then 0 <$ pop 1  -- property is absent, don't push anything
+            else return $ getresults + 1
         MemberMethod name f -> do
           pushName name
           udFnPusher ty f
diff --git a/test/HsLua/ObjectOrientationTests.hs b/test/HsLua/ObjectOrientationTests.hs
--- a/test/HsLua/ObjectOrientationTests.hs
+++ b/test/HsLua/ObjectOrientationTests.hs
@@ -134,6 +134,19 @@
           , "return result"
           ]
         forcePeek $ peekList peekText top
+
+    , "absent properties are not included in `pairs`" =:
+      [("num", "number"), ("str", "string"), ("show", "function")]
+      `shouldBeResultOf` do
+        openlibs
+        pushUD typeQux $ Quux 1 "a"
+        setglobal "a"
+        OK <- dostring $ Char8.unlines
+          [ "local result = {}"
+          , "for k, v in pairs(a) do result[#result+1] = {k, type(v)} end"
+          , "return result"
+          ]
+        forcePeek $ peekList (peekPair peekText peekText) top
     ]
 
   , testGroup "Bar type"
@@ -240,6 +253,14 @@
           -- msg <- forcePeek $ peekString top
           -- liftIO $ putStrLn msg
           forcePeek $ peekPoint top
+      , "absent alias returns `nil`" =:
+        TypeNil `shouldBeResultOf` do
+          openlibs
+          pushUD typeQux (Quux 9 "to five")
+          setglobal "quux"
+          dostring "return quux.x" >>= \case
+            OK -> ltype top
+            _ -> failLua =<< forcePeek (peekString top)
       ]
     ]
   ]