diff --git a/cornea.cabal b/cornea.cabal
--- a/cornea.cabal
+++ b/cornea.cabal
@@ -1,23 +1,23 @@
-cabal-version: 1.12
-name: cornea
-version: 0.3.0.1
-license: OtherLicense
-license-file: LICENSE
-copyright: 2019 Torsten Schmits
-maintainer: tek@tryp.io
-author: Torsten Schmits
-homepage: https://github.com/tek/cornea#readme
-bug-reports: https://github.com/tek/cornea/issues
-synopsis: classy optical monadic state
+cabal-version:      1.12
+name:               cornea
+version:            0.3.1.0
+license:            OtherLicense
+license-file:       LICENSE
+copyright:          2019 Torsten Schmits
+maintainer:         tek@tryp.io
+author:             Torsten Schmits
+homepage:           https://github.com/tek/cornea#readme
+bug-reports:        https://github.com/tek/cornea/issues
+synopsis:           classy optical monadic state
 description:
     Please see the README on GitHub at <https://github.com/tek/cornea>
-category: Lens
-build-type: Simple
-extra-source-files:
-    README.md
 
+category:           Lens
+build-type:         Simple
+extra-source-files: README.md
+
 source-repository head
-    type: git
+    type:     git
     location: https://github.com/tek/cornea
 
 library
@@ -28,23 +28,24 @@
         Cornea
         Data.DeepLenses
         Data.DeepPrisms
-    hs-source-dirs: lib
-    other-modules:
-        Prelude
-    default-language: Haskell2010
-    default-extensions: AllowAmbiguousTypes AutoDeriveTypeable
-                        BangPatterns BinaryLiterals ConstraintKinds DataKinds
-                        DefaultSignatures DeriveDataTypeable DeriveFoldable DeriveFunctor
-                        DeriveGeneric DeriveTraversable DoAndIfThenElse EmptyDataDecls
-                        ExistentialQuantification FlexibleContexts FlexibleInstances
-                        FunctionalDependencies GADTs GeneralizedNewtypeDeriving
-                        InstanceSigs KindSignatures LambdaCase MonadFailDesugaring
-                        MultiParamTypeClasses MultiWayIf NamedFieldPuns OverloadedStrings
-                        PartialTypeSignatures PatternGuards PolyKinds RankNTypes
-                        RecordWildCards ScopedTypeVariables StandaloneDeriving
-                        TemplateHaskell TupleSections TypeApplications TypeFamilies
-                        TypeSynonymInstances UndecidableInstances UnicodeSyntax
-                        ViewPatterns
+
+    hs-source-dirs:     lib
+    other-modules:      Prelude
+    default-language:   Haskell2010
+    default-extensions:
+        AllowAmbiguousTypes AutoDeriveTypeable BangPatterns BinaryLiterals
+        ConstraintKinds DataKinds DefaultSignatures DeriveDataTypeable
+        DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable
+        DoAndIfThenElse EmptyDataDecls ExistentialQuantification
+        FlexibleContexts FlexibleInstances FunctionalDependencies GADTs
+        GeneralizedNewtypeDeriving InstanceSigs KindSignatures LambdaCase
+        MonadFailDesugaring MultiParamTypeClasses MultiWayIf NamedFieldPuns
+        OverloadedStrings PartialTypeSignatures PatternGuards PolyKinds
+        RankNTypes RecordWildCards ScopedTypeVariables StandaloneDeriving
+        TemplateHaskell TupleSections TypeApplications TypeFamilies
+        TypeSynonymInstances UndecidableInstances UnicodeSyntax
+        ViewPatterns
+
     build-depends:
         base-noprelude >=4.7 && <5,
         either >=5.0.1.1 && <5.1,
@@ -58,30 +59,32 @@
         transformers >=0.5.6.2 && <0.6
 
 test-suite cornea-unit
-    type: exitcode-stdio-1.0
-    main-is: SpecMain.hs
-    hs-source-dirs: test/u
+    type:               exitcode-stdio-1.0
+    main-is:            SpecMain.hs
+    hs-source-dirs:     test/u
     other-modules:
         DeepErrorSpec
         DeepReaderSpec
         DeepStateSpec
         Prelude
         Paths_cornea
-    default-language: Haskell2010
-    default-extensions: AllowAmbiguousTypes AutoDeriveTypeable
-                        BangPatterns BinaryLiterals ConstraintKinds DataKinds
-                        DefaultSignatures DeriveDataTypeable DeriveFoldable DeriveFunctor
-                        DeriveGeneric DeriveTraversable DoAndIfThenElse EmptyDataDecls
-                        ExistentialQuantification FlexibleContexts FlexibleInstances
-                        FunctionalDependencies GADTs GeneralizedNewtypeDeriving
-                        InstanceSigs KindSignatures LambdaCase MonadFailDesugaring
-                        MultiParamTypeClasses MultiWayIf NamedFieldPuns OverloadedStrings
-                        PartialTypeSignatures PatternGuards PolyKinds RankNTypes
-                        RecordWildCards ScopedTypeVariables StandaloneDeriving
-                        TemplateHaskell TupleSections TypeApplications TypeFamilies
-                        TypeSynonymInstances UndecidableInstances UnicodeSyntax
-                        ViewPatterns
-    ghc-options: -threaded -rtsopts -with-rtsopts=-N
+
+    default-language:   Haskell2010
+    default-extensions:
+        AllowAmbiguousTypes AutoDeriveTypeable BangPatterns BinaryLiterals
+        ConstraintKinds DataKinds DefaultSignatures DeriveDataTypeable
+        DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable
+        DoAndIfThenElse EmptyDataDecls ExistentialQuantification
+        FlexibleContexts FlexibleInstances FunctionalDependencies GADTs
+        GeneralizedNewtypeDeriving InstanceSigs KindSignatures LambdaCase
+        MonadFailDesugaring MultiParamTypeClasses MultiWayIf NamedFieldPuns
+        OverloadedStrings PartialTypeSignatures PatternGuards PolyKinds
+        RankNTypes RecordWildCards ScopedTypeVariables StandaloneDeriving
+        TemplateHaskell TupleSections TypeApplications TypeFamilies
+        TypeSynonymInstances UndecidableInstances UnicodeSyntax
+        ViewPatterns
+
+    ghc-options:        -threaded -rtsopts -with-rtsopts=-N
     build-depends:
         HTF >=0.13.2.5 && <0.14,
         base-noprelude >=4.7 && <5,