diff --git a/monad-skeleton.cabal b/monad-skeleton.cabal
--- a/monad-skeleton.cabal
+++ b/monad-skeleton.cabal
@@ -1,5 +1,5 @@
 name:                monad-skeleton
-version:             0.1
+version:             0.1.1
 synopsis:            An undead monad
 description:         A simple operational monad based on Reflection without Remorse
 homepage:            https://github.com/fumieval/monad-skeleton
diff --git a/src/Control/Monad/Skeleton.hs b/src/Control/Monad/Skeleton.hs
--- a/src/Control/Monad/Skeleton.hs
+++ b/src/Control/Monad/Skeleton.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE RankNTypes, GADTs, PolyKinds #-}
+{-# LANGUAGE Trustworthy, RankNTypes, GADTs, PolyKinds #-}
 module Control.Monad.Skeleton (MonadView(..), hoistMonadView, Skeleton, bone, unbone, hoistSkeleton) where
 import qualified Data.Sequence as Seq
 import Unsafe.Coerce