diff --git a/character-cases.cabal b/character-cases.cabal
--- a/character-cases.cabal
+++ b/character-cases.cabal
@@ -4,12 +4,12 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 9b9be05bf0dac06ddeb62fdb730a6ee545b40639db89c4052d0d900da0aa40a5
+-- hash: 5614d4d110a1d3c8b6b1d2c616279aedf4fefc18a5bc46717901dc71da1e3306
 
 name:           character-cases
-version:        0.1.0.0
-synopsis:       Exposes subspecies types of Char. And naming cases. e.g. meaning of [a-z], [A-Z], [0-9], PascalCase, camelCase, and sneak_case.
-description:    Please see https://github.com/aiya000/hs-character-cases#README.md
+version:        0.1.0.1
+synopsis:       Exposes subspecies types of Char. And naming cases.
+description:    e.g. meaning of [a-z], [A-Z], [0-9], PascalCase, camelCase, and snake_case. Please see https://github.com/aiya000/hs-character-cases#README.md
 category:       Simple
 homepage:       https://github.com/aiya000/hs-character-cases#readme
 bug-reports:    https://github.com/aiya000/hs-character-cases/issues
@@ -33,7 +33,7 @@
       Paths_character_cases
   hs-source-dirs:
       src
-  default-extensions: AutoDeriveTypeable BangPatterns BinaryLiterals BlockArguments ConstraintKinds DataKinds DefaultSignatures DeriveDataTypeable DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable DoAndIfThenElse DuplicateRecordFields EmptyDataDecls ExistentialQuantification FlexibleContexts FlexibleInstances FunctionalDependencies GADTs GeneralizedNewtypeDeriving InstanceSigs KindSignatures LambdaCase MonadFailDesugaring MultiParamTypeClasses MultiWayIf NamedFieldPuns OverloadedStrings PartialTypeSignatures PatternGuards PolyKinds RankNTypes RecordWildCards ScopedTypeVariables StandaloneDeriving TupleSections TypeApplications TypeFamilies TypeSynonymInstances ViewPatterns
+  default-extensions: BangPatterns BinaryLiterals BlockArguments ConstraintKinds DataKinds DefaultSignatures DeriveDataTypeable DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable DoAndIfThenElse DuplicateRecordFields EmptyDataDecls ExistentialQuantification FlexibleContexts FlexibleInstances FunctionalDependencies GADTs GeneralizedNewtypeDeriving InstanceSigs KindSignatures LambdaCase MultiParamTypeClasses MultiWayIf NamedFieldPuns OverloadedStrings PartialTypeSignatures PatternGuards PolyKinds RankNTypes RecordWildCards ScopedTypeVariables StandaloneDeriving TupleSections TypeApplications TypeFamilies TypeSynonymInstances ViewPatterns
   ghc-options: -Wall -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wredundant-constraints -fprint-explicit-kinds -fprint-potential-instances
   build-depends:
       base >=4.7 && <5
@@ -55,7 +55,7 @@
   hs-source-dirs:
       test/doctest
       src
-  default-extensions: AutoDeriveTypeable BangPatterns BinaryLiterals BlockArguments ConstraintKinds DataKinds DefaultSignatures DeriveDataTypeable DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable DoAndIfThenElse DuplicateRecordFields EmptyDataDecls ExistentialQuantification FlexibleContexts FlexibleInstances FunctionalDependencies GADTs GeneralizedNewtypeDeriving InstanceSigs KindSignatures LambdaCase MonadFailDesugaring MultiParamTypeClasses MultiWayIf NamedFieldPuns OverloadedStrings PartialTypeSignatures PatternGuards PolyKinds RankNTypes RecordWildCards ScopedTypeVariables StandaloneDeriving TupleSections TypeApplications TypeFamilies TypeSynonymInstances ViewPatterns
+  default-extensions: BangPatterns BinaryLiterals BlockArguments ConstraintKinds DataKinds DefaultSignatures DeriveDataTypeable DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable DoAndIfThenElse DuplicateRecordFields EmptyDataDecls ExistentialQuantification FlexibleContexts FlexibleInstances FunctionalDependencies GADTs GeneralizedNewtypeDeriving InstanceSigs KindSignatures LambdaCase MultiParamTypeClasses MultiWayIf NamedFieldPuns OverloadedStrings PartialTypeSignatures PatternGuards PolyKinds RankNTypes RecordWildCards ScopedTypeVariables StandaloneDeriving TupleSections TypeApplications TypeFamilies TypeSynonymInstances ViewPatterns
   ghc-options: -Wall -Wcompat -Wincomplete-record-updates -Wincomplete-uni-patterns -Wredundant-constraints -fprint-explicit-kinds -fprint-potential-instances -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       Glob
diff --git a/src/Cases/Megaparsec.hs b/src/Cases/Megaparsec.hs
--- a/src/Cases/Megaparsec.hs
+++ b/src/Cases/Megaparsec.hs
@@ -3,4 +3,4 @@
 import Data.Void
 import Text.Megaparsec (MonadParsec)
 
-type CodeParsing = MonadParsec Void String
+type CodeParsing m = (MonadParsec Void String m, MonadFail m)