diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,15 @@
 
 `hslua-marshalling` uses [PVP Versioning][].
 
+## hslua-marshalling-2.2.0
+
+Released 2022-02-19.
+
+-   `Result` is now an instance of Foldable and Traversable.
+    Both `Result` and `Peek` are made instances of `MonadPlus`.
+
+-   Require hslua-core-2.2.0.
+
 ## hslua-marshalling-2.1.0
 
 Released 29-01-2022.
diff --git a/hslua-marshalling.cabal b/hslua-marshalling.cabal
--- a/hslua-marshalling.cabal
+++ b/hslua-marshalling.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.2
 name:                hslua-marshalling
-version:             2.1.0
+version:             2.2.0
 synopsis:            Marshalling of values between Haskell and Lua.
 description:         Provides functions to marshal values from Haskell
                      to Lua, and /vice versa/.
@@ -39,7 +39,7 @@
   build-depends:       base              >= 4.8    && < 5
                      , bytestring        >= 0.10.2 && < 0.12
                      , containers        >= 0.5.9  && < 0.7
-                     , hslua-core        >= 2.0    && < 2.2
+                     , hslua-core        >= 2.2    && < 2.3
                      , mtl               >= 2.2    && < 2.3
                      , text              >= 1.2    && < 2.1
   ghc-options:         -Wall
diff --git a/src/HsLua/Marshalling/Peek.hs b/src/HsLua/Marshalling/Peek.hs
--- a/src/HsLua/Marshalling/Peek.hs
+++ b/src/HsLua/Marshalling/Peek.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE CPP                 #-}
-{-# LANGUAGE DeriveFunctor       #-}
+{-# LANGUAGE DeriveTraversable   #-}
 {-# LANGUAGE OverloadedStrings   #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-|
@@ -33,7 +33,7 @@
   ) where
 
 import Control.Applicative (Alternative (..))
-import Control.Monad ((<$!>), (<=<))
+import Control.Monad ((<$!>), (<=<), MonadPlus)
 import Data.ByteString (ByteString)
 import Data.List (intercalate)
 import HsLua.Core as Lua
@@ -50,7 +50,7 @@
 data Result a
   = Success !a
   | Failure ByteString [Name]       -- ^ Error message and stack of contexts
-  deriving (Show, Eq, Functor)
+  deriving (Show, Eq, Foldable, Functor, Traversable)
 
 instance Applicative Result where
   pure = Success
@@ -71,6 +71,8 @@
     _          -> x
   {-# INLINE (<|>) #-}
 
+instance MonadPlus Result
+
 --
 -- Peek
 --
@@ -123,6 +125,8 @@
     Success ra -> return (pure ra)
     _          -> runPeek b
   {-# INLINE (<|>) #-}
+
+instance MonadPlus (Peek e)
 
 instance MonadFail (Peek e) where
   fail = Peek . return . failure . Utf8.fromString
diff --git a/src/HsLua/Marshalling/Userdata.hs b/src/HsLua/Marshalling/Userdata.hs
--- a/src/HsLua/Marshalling/Userdata.hs
+++ b/src/HsLua/Marshalling/Userdata.hs
@@ -58,6 +58,6 @@
 
     pushInitialState :: LuaE e ()
     pushInitialState = do
-      newhsuserdata @[a] xs
+      newhsuserdatauv @[a] xs 0
       void (newudmetatable statename)
       setmetatable (nth 2)