diff --git a/Control/Exception/Assert/Sugar.hs b/Control/Exception/Assert/Sugar.hs
--- a/Control/Exception/Assert/Sugar.hs
+++ b/Control/Exception/Assert/Sugar.hs
@@ -11,13 +11,14 @@
 -- no effect at all.
 module Control.Exception.Assert.Sugar
   ( assert, blame, showFailure, swith, allB
-  , failure, twith, forceEither
+    -- * DEPRECATED
+  , twith, failure, forceEither
   ) where
 
-import Control.Exception (assert)
-import Data.Text (Text)
-import Debug.Trace (trace)
-import Prelude
+import           Control.Exception (assert)
+import           Data.Text (Text)
+import           Debug.Trace (trace)
+import           Prelude
 import qualified Text.Show.Pretty as Show.Pretty (ppShow)
 
 infix 1 `blame`
@@ -26,34 +27,14 @@
 --
 -- > assert (age < 120 `blame` age) $ savings / (120 - age)
 blame :: Show a => Bool -> a -> Bool
-{-# INLINE blame #-}
+{-# NOINLINE blame #-}
 blame True _ = True
 blame False blamed = trace (blameMessage blamed) False
 
 blameMessage :: Show a => a -> String
-{-# NOINLINE blameMessage #-}
 blameMessage blamed = "Contract failed and the following is to blame:\n  "
                       ++ Show.Pretty.ppShow blamed
 
-infix 1 `failure`
--- | Like 'error', but shows the source position (in newer GHCs
--- @error@ shows source position as well, hence deprecation)
--- and also the value to blame for the failure. To be used as in
---
--- > case xs of
--- >   0 : _ -> assert `failure` (xs, "has an insignificant zero")
-{-# DEPRECATED failure
-      "use 'error' and 'showFailure' instead, now that 'error' prints source positions." #-}
-failure :: Show a => (forall x. Bool -> x -> x) -> a -> b
-{-# NOINLINE failure #-}
-failure asrt blamed =
-  let s = "Internal failure occurred and the following is to blame:\n  "
-          ++ Show.Pretty.ppShow blamed
-  in trace s
-     $ asrt False
-     $ error "Control.Exception.Assert.Sugar.failure"
-         -- Lack of no-ignore-asserts or GHC < 7.4.
-
 infix 2 `showFailure`
 -- | A helper function for 'error'. To be used as in
 --
@@ -70,18 +51,6 @@
   ++ s ++ "\n  "
   ++ Show.Pretty.ppShow v
 
-infix 2 `twith`
--- | Syntactic sugar for the pair operation, to be used for 'blame' as in
---
--- > assert (age < 120 `blame` "age too high" `twith` age) $ savings / (120 - age)
--- Fixing the first component of the pair to @Text@ prevents warnings
--- about defaulting, even when @OverloadedStrings@ extension is enabled.
-{-# DEPRECATED twith
-      "consider using 'swith' instead, for simplicity, because GHC optimizes lazy 'String' constants very well." #-}
-twith :: Text -> b -> (Text, b)
-{-# INLINE twith #-}
-twith t b = (t, b)
-
 infix 2 `swith`
 -- | Syntactic sugar for the pair operation, to be used for 'blame' as in
 --
@@ -98,14 +67,46 @@
 --
 -- > assert (allB (<= height) [yf, y1, y2])
 allB :: Show a => (a -> Bool) -> [a] -> Bool
-{-# INLINE allB #-}
+{-# NOINLINE allB #-}
 allB predicate l = blame (all predicate l) $ allBMessage predicate l
 
 allBMessage :: Show a => (a -> Bool) -> [a] -> String
-{-# NOINLINE allBMessage #-}
 allBMessage predicate l = Show.Pretty.ppShow (filter (not . predicate) l)
                           ++ " in the context of "
                           ++ Show.Pretty.ppShow l
+
+-- * DEPRECATED
+
+infix 2 `twith`
+-- | Syntactic sugar for the pair operation, to be used for 'blame' as in
+--
+-- > assert (age < 120 `blame` "age too high" `twith` age) $ savings / (120 - age)
+-- Fixing the first component of the pair to @Text@ prevents warnings
+-- about defaulting, even when @OverloadedStrings@ extension is enabled.
+{-# DEPRECATED twith
+      "consider using 'swith' instead, for simplicity, because GHC optimizes lazy 'String' constants very well." #-}
+twith :: Text -> b -> (Text, b)
+{-# INLINE twith #-}
+twith t b = (t, b)
+
+infix 1 `failure`
+-- | Like 'error', but shows the source position (in newer GHCs
+-- @error@ shows source position as well, hence deprecation)
+-- and also the value to blame for the failure. To be used as in
+--
+-- > case xs of
+-- >   0 : _ -> assert `failure` (xs, "has an insignificant zero")
+{-# DEPRECATED failure
+      "use 'error' and 'showFailure' instead, now that 'error' prints source positions." #-}
+failure :: Show a => (forall x. Bool -> x -> x) -> a -> b
+{-# NOINLINE failure #-}
+failure asrt blamed =
+  let s = "Internal failure occurred and the following is to blame:\n  "
+          ++ Show.Pretty.ppShow blamed
+  in trace s
+     $ asrt False
+     $ error "Control.Exception.Assert.Sugar.failure"
+         -- Lack of no-ignore-asserts or GHC < 7.4.
 
 infix 1 `forceEither`
 -- | Assuming that @Left@ signifies an error condition,
diff --git a/assert-failure.cabal b/assert-failure.cabal
--- a/assert-failure.cabal
+++ b/assert-failure.cabal
@@ -1,3 +1,4 @@
+cabal-version: >= 1.10
 name:          assert-failure
 -- The package version. See the Haskell package versioning policy (PVP)
 -- for standards guiding when and how versions should be incremented.
@@ -5,7 +6,7 @@
 -- PVP summary:+-+------- breaking API changes
 --             | | +----- non-breaking API additions
 --             | | | +--- code changes with no API change
-version:       0.1.2.3
+version:       0.1.2.4
 synopsis:      Syntactic sugar improving 'assert' and 'error'
 description:   This library contains syntactic sugar that makes it easier
                to write simple contracts with 'assert' and 'error'
@@ -14,13 +15,12 @@
 bug-reports:   https://github.com/Mikolaj/assert-failure/issues
 license:       BSD3
 license-file:  LICENSE
-tested-with:   GHC >= 7.6 && <= 8.10
+tested-with:   GHC >= 7.10 && <= 8.10
 data-files:    LICENSE, README.md
 author:        Mikolaj Konarski
 maintainer:    Mikolaj Konarski <mikolaj.konarski@funktory.com>
 category:      Control, Contract
 build-type:    Simple
-cabal-version: >= 1.10
 
 source-repository head
   type:               git
@@ -35,8 +35,11 @@
 
   default-language:   Haskell2010
   default-extensions: MonoLocalBinds, ScopedTypeVariables, OverloadedStrings
-                      BangPatterns, RecordWildCards, NamedFieldPuns, MultiWayIf
+                      BangPatterns, RecordWildCards, NamedFieldPuns, MultiWayIf,
+                      LambdaCase, DefaultSignatures, InstanceSigs,
+                      PatternSynonyms
+-- TODO: , StrictData
   other-extensions:   RankNTypes
   ghc-options:        -Wall -fwarn-orphans -fwarn-incomplete-uni-patterns -fwarn-incomplete-record-updates -fwarn-implicit-prelude -fwarn-identities
--- TODO:  ghc-options:        -Wall -Wcompat -Worphans -Wincomplete-uni-patterns -Wincomplete-record-updates -Wimplicit-prelude -Wmissing-home-modules -Widentities
+-- TODO:  ghc-options:        -Wall -Wcompat -Worphans -Wincomplete-uni-patterns -Wincomplete-record-updates -Wimplicit-prelude -Wmissing-home-modules -Widentities -Wredundant-constraints -Wmissing-export-lists -Wpartial-fields
   ghc-options:        -fno-ignore-asserts