diff --git a/salak-toml.cabal b/salak-toml.cabal
--- a/salak-toml.cabal
+++ b/salak-toml.cabal
@@ -1,6 +1,6 @@
 cabal-version: 1.12
 name: salak-toml
-version: 0.3.3
+version: 0.3.3.2
 license: MIT
 license-file: LICENSE
 copyright: 2019 Daniel YU
@@ -21,11 +21,13 @@
     other-modules:
         Paths_salak_toml
     default-language: Haskell2010
-    default-extensions: RecordWildCards
+    default-extensions: RecordWildCards TupleSections OverloadedStrings
+                        ScopedTypeVariables FlexibleInstances MultiParamTypeClasses
+                        DeriveGeneric
     ghc-options: -Wall -fno-warn-orphans -fno-warn-missing-signatures
     build-depends:
         base >=4.10 && <5,
-        salak >=0.3.3 && <0.4,
+        salak >=0.3.3.2 && <0.4,
         text >=1.2.3.1 && <1.3,
         time >=1.8.0.2 && <1.9,
         tomland >=1.0 && <1.2,
@@ -39,7 +41,9 @@
         Salak.Toml
         Paths_salak_toml
     default-language: Haskell2010
-    default-extensions: RecordWildCards
+    default-extensions: RecordWildCards TupleSections OverloadedStrings
+                        ScopedTypeVariables FlexibleInstances MultiParamTypeClasses
+                        DeriveGeneric
     ghc-options: -Wall -fno-warn-orphans -fno-warn-missing-signatures
     build-depends:
         QuickCheck >=2.13.2 && <2.14,
@@ -47,7 +51,7 @@
         exceptions >=0.10.2 && <0.11,
         hspec ==2.*,
         mtl >=2.2.2 && <2.3,
-        salak >=0.3.3 && <0.4,
+        salak >=0.3.3.2 && <0.4,
         text >=1.2.3.1 && <1.3,
         time >=1.8.0.2 && <1.9,
         tomland >=1.0 && <1.2,
diff --git a/src/Salak/Toml.hs b/src/Salak/Toml.hs
--- a/src/Salak/Toml.hs
+++ b/src/Salak/Toml.hs
@@ -41,8 +41,8 @@
 instance HasLoad TOML where
   loaders _ = (, loadToml) <$> ["toml", "tml"]
 
-toSs :: T.Key -> [Key]
-toSs (T.Key ps) = toS <$> N.toList ps
+toSs :: T.Key -> Keys
+toSs (T.Key ps) = fromKeys $ toS <$> N.toList ps
 
 toS :: Piece -> Key
 toS = KT . unPiece
@@ -54,12 +54,12 @@
   . foldTableArrays tomlTableArrays
   where
     foldToml go p t = HM.foldlWithKey' go t p
-    foldPairs       = foldToml (\s k v -> TR.modify' (Keys $ toSs k) (insertAnyValue i v) s)
+    foldPairs       = foldToml (\s k v -> TR.modify' (toSs k) (insertAnyValue i v) s)
     foldTableArrays = foldToml (\s _ v -> foldArray (N.toList v) (loadTOML i) s)
     foldTables      = foldToml (\s _ v -> go v s)
       where
-        go (Leaf   k toml)    = TR.modify' (Keys $ toSs k) (loadTOML i toml)
-        go (Branch k v tomap) = TR.modify' (Keys $ toSs k) (foldTables tomap) . maybe id (loadTOML i) v
+        go (Leaf   k toml)    = TR.modify' (toSs k) (loadTOML i toml)
+        go (Branch k v tomap) = TR.modify' (toSs k) (foldTables tomap) . maybe id (loadTOML i) v
 insertAnyValue :: Int -> AnyValue -> TraceSource -> TraceSource
 insertAnyValue i (AnyValue (Array   b))             ts = foldArray b (insertAnyValue i . AnyValue) ts
 insertAnyValue i (AnyValue (Bool    b))             ts = setVal i (VB  b) ts
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -50,17 +50,17 @@
 data SubConf = SubConf
   { hello :: String } deriving (Eq, Show, Generic)
 
-instance Monad m => FromProp m SubConf where
+instance FromProp m SubConf where
   fromProp = SubConf <$> "hello" .?= "yyy"
 
-instance Monad m => FromProp m Conf
+instance FromProp m Conf
 
 tomlProperty :: SpecWith ()
 tomlProperty = do
   context "load toml" $ do
     it "salak.toml" $ do
       loadAndRunSalak (loadToml "test/salak.toml") $ do
-        SourcePack{..}  <- askSalak
+        SourcePack{..}  <- ask
         cf <- require "me.icymint.conf"
         lift $ do
           name cf `shouldBe` "shelly"