diff --git a/.hlint.yaml b/.hlint.yaml
--- a/.hlint.yaml
+++ b/.hlint.yaml
@@ -5,3 +5,5 @@
 
 - ignore:
     name: Use lambda-case
+
+- ignore: {name: Hoist not, within: [Ersatz.Bit]} # This is how we define `any`, ya dingus
diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,7 @@
 #
 # For more information, see https://github.com/haskell-CI/haskell-ci
 #
-# version: 0.3.20190521
+# version: 0.7.20191105
 #
 language: c
 dist: xenial
@@ -22,6 +22,7 @@
   directories:
     - $HOME/.cabal/packages
     - $HOME/.cabal/store
+    - $HOME/.hlint
 before_cache:
   - rm -fv $CABALHOME/packages/hackage.haskell.org/build-reports.log
   # remove files that are regenerated by 'cabal update'
@@ -35,32 +36,31 @@
   include:
     - compiler: ghc-8.8.1
       addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.8.1","cabal-install-3.0","minisat"]}}
-      env: GHCHEAD=true
     - compiler: ghc-8.6.5
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.6.5","cabal-install-2.4","minisat"]}}
+      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.6.5","cabal-install-3.0","minisat"]}}
     - compiler: ghc-8.4.4
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.4.4","cabal-install-2.4","minisat"]}}
+      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.4.4","cabal-install-3.0","minisat"]}}
     - compiler: ghc-8.2.2
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.2.2","cabal-install-2.4","minisat"]}}
+      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.2.2","cabal-install-3.0","minisat"]}}
     - compiler: ghc-8.0.2
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.0.2","cabal-install-2.4","minisat"]}}
+      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.0.2","cabal-install-3.0","minisat"]}}
     - compiler: ghc-7.10.3
-      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-7.10.3","cabal-install-2.4","minisat"]}}
+      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-7.10.3","cabal-install-3.0","minisat"]}}
     - compiler: ghc-head
       addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-head","cabal-install-head","minisat"]}}
-      env: GHCHEAD=true
   allow_failures:
     - compiler: ghc-head
-    - compiler: ghc-8.8.1
 before_install:
   - HC=$(echo "/opt/$CC/bin/ghc" | sed 's/-/\//')
+  - WITHCOMPILER="-w $HC"
+  - HADDOCK=$(echo "/opt/$CC/bin/haddock" | sed 's/-/\//')
   - HCPKG="$HC-pkg"
   - unset CC
   - CABAL=/opt/ghc/bin/cabal
   - CABALHOME=$HOME/.cabal
   - export PATH="$CABALHOME/bin:$PATH"
   - TOP=$(pwd)
-  - HCNUMVER=$(( $(${HC} --numeric-version|sed -E 's/([0-9]+)\.([0-9]+)\.([0-9]+).*/\1 * 10000 + \2 * 100 + \3/') ))
+  - "HCNUMVER=$(${HC} --numeric-version|perl -ne '/^(\\d+)\\.(\\d+)\\.(\\d+)(\\.(\\d+))?$/; print(10000 * $1 + 100 * $2 + ($3 == 0 ? $5 != 1 : $3))')"
   - echo $HCNUMVER
   - CABAL="$CABAL -vnormal+nowrap+markoutput"
   - set -o pipefail
@@ -87,56 +87,70 @@
   - echo "$(${HC} --version) [$(${HC} --print-project-git-commit-id 2> /dev/null || echo '?')]"
   - TEST=--enable-tests
   - BENCH=--enable-benchmarks
-  - GHCHEAD=${GHCHEAD-false}
+  - HEADHACKAGE=false
+  - if [ $HCNUMVER -gt 80801 ] ; then HEADHACKAGE=true ; fi
   - rm -f $CABALHOME/config
   - |
-    echo "verbose: normal +nowrap +markoutput"          >> $CABALHOME/config
-    echo "remote-build-reporting: anonymous"            >> $CABALHOME/config
-    echo "remote-repo-cache: $CABALHOME/packages"       >> $CABALHOME/config
-    echo "logs-dir:          $CABALHOME/logs"           >> $CABALHOME/config
-    echo "world-file:        $CABALHOME/world"          >> $CABALHOME/config
-    echo "extra-prog-path:   $CABALHOME/bin"            >> $CABALHOME/config
-    echo "symlink-bindir:    $CABALHOME/bin"            >> $CABALHOME/config
-    echo "installdir:        $CABALHOME/bin"            >> $CABALHOME/config
-    echo "build-summary:     $CABALHOME/logs/build.log" >> $CABALHOME/config
-    echo "store-dir:         $CABALHOME/store"          >> $CABALHOME/config
-    echo "install-dirs user"                            >> $CABALHOME/config
-    echo "  prefix: $CABALHOME"                         >> $CABALHOME/config
-    echo "repository hackage.haskell.org"               >> $CABALHOME/config
-    echo "  url: http://hackage.haskell.org/"           >> $CABALHOME/config
+    echo "verbose: normal +nowrap +markoutput"                                  >> $CABALHOME/config
+    echo "remote-build-reporting: anonymous"                                    >> $CABALHOME/config
+    echo "write-ghc-environment-files: always"                                  >> $CABALHOME/config
+    echo "remote-repo-cache: $CABALHOME/packages"                               >> $CABALHOME/config
+    echo "logs-dir:          $CABALHOME/logs"                                   >> $CABALHOME/config
+    echo "world-file:        $CABALHOME/world"                                  >> $CABALHOME/config
+    echo "extra-prog-path:   $CABALHOME/bin"                                    >> $CABALHOME/config
+    echo "symlink-bindir:    $CABALHOME/bin"                                    >> $CABALHOME/config
+    echo "installdir:        $CABALHOME/bin"                                    >> $CABALHOME/config
+    echo "build-summary:     $CABALHOME/logs/build.log"                         >> $CABALHOME/config
+    echo "store-dir:         $CABALHOME/store"                                  >> $CABALHOME/config
+    echo "install-dirs user"                                                    >> $CABALHOME/config
+    echo "  prefix: $CABALHOME"                                                 >> $CABALHOME/config
+    echo "repository hackage.haskell.org"                                       >> $CABALHOME/config
+    echo "  url: http://hackage.haskell.org/"                                   >> $CABALHOME/config
+    echo "  secure: True"                                                       >> $CABALHOME/config
+    echo "  key-threshold: 3"                                                   >> $CABALHOME/config
+    echo "  root-keys:"                                                         >> $CABALHOME/config
+    echo "    fe331502606802feac15e514d9b9ea83fee8b6ffef71335479a2e68d84adc6b0" >> $CABALHOME/config
+    echo "    1ea9ba32c526d1cc91ab5e5bd364ec5e9e8cb67179a471872f6e26f0ae773d42" >> $CABALHOME/config
+    echo "    2c6c3627bd6c982990239487f1abd02e08a02e6cf16edb105a8012d444d870c3" >> $CABALHOME/config
+    echo "    0a5c7ea47cd1b15f01f5f51a33adda7e655bc0f0b0615baa8e271f4c3351e21d" >> $CABALHOME/config
+    echo "    51f0161b906011b52c6613376b1ae937670da69322113a246a09f807c62f6921" >> $CABALHOME/config
   - |
-    if $GHCHEAD; then
+    if $HEADHACKAGE; then
     echo "allow-newer: $($HCPKG list --simple-output | sed -E 's/([a-zA-Z-]+)-[0-9.]+/*:\1/g')" >> $CABALHOME/config
-    
-    echo "repository head.hackage"                                                        >> $CABALHOME/config
-    echo "   url: http://head.hackage.haskell.org/"                                       >> $CABALHOME/config
+    echo "repository head.hackage.ghc.haskell.org"                                        >> $CABALHOME/config
+    echo "   url: https://ghc.gitlab.haskell.org/head.hackage/"                           >> $CABALHOME/config
     echo "   secure: True"                                                                >> $CABALHOME/config
-    echo "   root-keys: 07c59cb65787dedfaef5bd5f987ceb5f7e5ebf88b904bbd4c5cbdeb2ff71b740" >> $CABALHOME/config
-    echo "              2e8555dde16ebd8df076f1a8ef13b8f14c66bad8eafefd7d9e37d0ed711821fb" >> $CABALHOME/config
-    echo "              8f79fd2389ab2967354407ec852cbe73f2e8635793ac446d09461ffb99527f6e" >> $CABALHOME/config
+    echo "   root-keys: 7541f32a4ccca4f97aea3b22f5e593ba2c0267546016b992dfadcd2fe944e55d" >> $CABALHOME/config
+    echo "              26021a13b401500c8eb2761ca95c61f2d625bfef951b939a8124ed12ecf07329" >> $CABALHOME/config
+    echo "              f76d08be13e9a61a377a85e2fb63f4c5435d40f8feb3e12eb05905edb8cdea89" >> $CABALHOME/config
     echo "   key-threshold: 3"                                                            >> $CABALHOME/config
     fi
+  - |
+    echo "program-default-options"                >> $CABALHOME/config
+    echo "  ghc-options: $GHCJOBS +RTS -M6G -RTS" >> $CABALHOME/config
   - cat $CABALHOME/config
   - rm -fv cabal.project cabal.project.local cabal.project.freeze
   - travis_retry ${CABAL} v2-update -v
+  - if [ $HCNUMVER -ge 80800 ] && [ $HCNUMVER -lt 80802 ] ; then HLINTVER=$(cd /tmp && (${CABAL} v2-install -v $WITHCOMPILER --dry-run hlint  --constraint='hlint ==2.2.*' |  perl -ne 'if (/\bhlint-(\d+(\.\d+)*)\b/) { print "$1"; last; }')); echo "HLint version $HLINTVER" ; fi
+  - "if [ $HCNUMVER -ge 80800 ] && [ $HCNUMVER -lt 80802 ] ; then if [ ! -e $HOME/.hlint/hlint-$HLINTVER/hlint ]; then echo \"Downloading HLint version $HLINTVER\"; mkdir -p $HOME/.hlint; curl --write-out 'Status Code: %{http_code} Redirects: %{num_redirects} Total time: %{time_total} Total Dsize: %{size_download}\\n' --silent --location --output $HOME/.hlint/hlint-$HLINTVER.tar.gz \"https://github.com/ndmitchell/hlint/releases/download/v$HLINTVER/hlint-$HLINTVER-x86_64-linux.tar.gz\"; tar -xzv -f $HOME/.hlint/hlint-$HLINTVER.tar.gz -C $HOME/.hlint; fi ; fi"
+  - if [ $HCNUMVER -ge 80800 ] && [ $HCNUMVER -lt 80802 ] ; then mkdir -p $CABALHOME/bin && ln -sf "$HOME/.hlint/hlint-$HLINTVER/hlint" $CABALHOME/bin/hlint ; fi
+  - if [ $HCNUMVER -ge 80800 ] && [ $HCNUMVER -lt 80802 ] ; then hlint --version ; fi
   # Generate cabal.project
   - rm -rf cabal.project cabal.project.local cabal.project.freeze
   - touch cabal.project
   - |
-    echo 'packages: "."' >> cabal.project
+    echo "packages: ." >> cabal.project
   - |
-    echo "package ersatz"                      >> cabal.project
-    echo "  flags: +examples"                  >> cabal.project
-    echo ""                                    >> cabal.project
-    echo "write-ghc-environment-files: always" >> cabal.project
+    echo "package ersatz"     >> cabal.project
+    echo "  flags: +examples" >> cabal.project
   - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(ersatz)$' || true) | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
   - cat cabal.project || true
   - cat cabal.project.local || true
   - if [ -f "./configure.ac" ]; then (cd "." && autoreconf -i); fi
-  - ${CABAL} v2-freeze -w ${HC} ${TEST} ${BENCH} | color_cabal_output
+  - ${CABAL} v2-freeze $WITHCOMPILER ${TEST} ${BENCH} | color_cabal_output
   - "cat cabal.project.freeze | sed -E 's/^(constraints: *| *)//' | sed 's/any.//'"
   - rm  cabal.project.freeze
-  - ${CABAL} v2-build -w ${HC} ${TEST} ${BENCH} --dep -j2 all | color_cabal_output
+  - ${CABAL} v2-build $WITHCOMPILER ${TEST} ${BENCH} --dep -j2 all | color_cabal_output
 script:
   - DISTDIR=$(mktemp -d /tmp/dist-test.XXXX)
   # Packaging...
@@ -144,29 +158,33 @@
   # Unpacking...
   - mv dist-newstyle/sdist/*.tar.gz ${DISTDIR}/
   - cd ${DISTDIR} || false
-  - find . -maxdepth 1 -name '*.tar.gz' -exec tar -xvf '{}' \;
+  - find . -maxdepth 1 -type f -name '*.tar.gz' -exec tar -xvf '{}' \;
+  - find . -maxdepth 1 -type f -name '*.tar.gz' -exec rm       '{}' \;
+  - PKGDIR_ersatz="$(find . -maxdepth 1 -type d -regex '.*/ersatz-[0-9.]*')"
   # Generate cabal.project
   - rm -rf cabal.project cabal.project.local cabal.project.freeze
   - touch cabal.project
   - |
-    echo 'packages: "ersatz-*/*.cabal"' >> cabal.project
+    echo "packages: ${PKGDIR_ersatz}" >> cabal.project
   - |
-    echo "package ersatz"                      >> cabal.project
-    echo "  flags: +examples"                  >> cabal.project
-    echo ""                                    >> cabal.project
-    echo "write-ghc-environment-files: always" >> cabal.project
+    echo "package ersatz"     >> cabal.project
+    echo "  flags: +examples" >> cabal.project
   - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(ersatz)$' || true) | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
   - cat cabal.project || true
   - cat cabal.project.local || true
   # Building with tests and benchmarks...
   # build & run tests, build benchmarks
-  - ${CABAL} v2-build -w ${HC} ${TEST} ${BENCH} all | color_cabal_output
+  - ${CABAL} v2-build $WITHCOMPILER ${TEST} ${BENCH} all | color_cabal_output
   # Testing...
-  - ${CABAL} v2-test -w ${HC} ${TEST} ${BENCH} all | color_cabal_output
+  - ${CABAL} v2-test $WITHCOMPILER ${TEST} ${BENCH} all | color_cabal_output
+  # HLint..
+  - if [ $HCNUMVER -ge 80800 ] && [ $HCNUMVER -lt 80802 ] ; then (cd ${PKGDIR_ersatz} && hlint src) ; fi
+  - if [ $HCNUMVER -ge 80800 ] && [ $HCNUMVER -lt 80802 ] ; then (cd ${PKGDIR_ersatz} && hlint examples/sudoku) ; fi
+  - if [ $HCNUMVER -ge 80800 ] && [ $HCNUMVER -lt 80802 ] ; then (cd ${PKGDIR_ersatz} && hlint examples/regexp-grid) ; fi
   # cabal check...
-  - (cd ersatz-* && ${CABAL} -vnormal check)
+  - (cd ${PKGDIR_ersatz} && ${CABAL} -vnormal check)
   # haddock...
-  - ${CABAL} v2-haddock -w ${HC} ${TEST} ${BENCH} all | color_cabal_output
+  - ${CABAL} v2-haddock $WITHCOMPILER --with-haddock $HADDOCK ${TEST} ${BENCH} all | color_cabal_output
 
-# REGENDATA ["--output=.travis.yml","--config=cabal.haskell-ci","cabal.project"]
+# REGENDATA ("0.7.20191105",["--output=.travis.yml","--config=cabal.haskell-ci","cabal.project"])
 # EOF
diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+0.4.8 [2020.01.29]
+------------------
+* Add `MonadSAT` and `MonadQSAT`
+* Achieve forward compatibility with
+  [GHC proposal 229](https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0229-whitespace-bang-patterns.rst).
+
 0.4.7 [2019.06.01]
 ------------------
 * Add `anyminisat` and `trySolvers`
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -44,7 +44,7 @@
 To allocate fresh existentially or universally quantified variables or to assert that a Bit is true and add the attendant circuit with sharing to the current problem you use the SAT monad.
 
 ```haskell
-verify_currying :: (MonadState s m, HasQSAT s) => m ()
+verify_currying :: (MonadQSAT s m) => m ()
 verify_currying = do
   (x::Bit, y::Bit, z::Bit) <- forall
   assert $ ((x && y) ==> z) === (x ==> y ==> z)
diff --git a/ersatz.cabal b/ersatz.cabal
--- a/ersatz.cabal
+++ b/ersatz.cabal
@@ -1,5 +1,5 @@
 name:           ersatz
-version:        0.4.7
+version:        0.4.8
 license:        BSD3
 license-file:   LICENSE
 author:         Edward A. Kmett, Eric Mertens, Johan Kiviniemi
@@ -308,12 +308,12 @@
   type: exitcode-stdio-1.0
   main-is: Moore.hs
   hs-source-dirs: tests
-  build-depends: base, array, mtl, ersatz
+  build-depends: base, array, ersatz
   default-language: Haskell2010
 
 test-suite z001
   type: exitcode-stdio-1.0
   main-is: Z001.hs
   hs-source-dirs: tests
-  build-depends: base, mtl, ersatz
+  build-depends: base, ersatz
   default-language: Haskell2010
diff --git a/examples/regexp-grid/RegexpGrid/Problem.hs b/examples/regexp-grid/RegexpGrid/Problem.hs
--- a/examples/regexp-grid/RegexpGrid/Problem.hs
+++ b/examples/regexp-grid/RegexpGrid/Problem.hs
@@ -59,7 +59,7 @@
   {-# INLINE mappend #-}
 #endif
 
-problem :: (Applicative m, Fail.MonadFail m, MonadState s m, HasSAT s)
+problem :: (Applicative m, Fail.MonadFail m, MonadSAT s m)
         => m (Map Pos Field)
 problem = do
   -- Allocate a literal for each field.
@@ -67,7 +67,7 @@
   runReaderT problem' fieldMap
   return fieldMap
 
-problem' :: (Fail.MonadFail m, MonadState s m, HasSAT s)
+problem' :: (Fail.MonadFail m, MonadSAT s m)
          => ReaderT (Map Pos Field) m ()
 problem' = do
   r [P00,P01,P02,P03,P04,P05,P06] ".*H.*H.*"
@@ -112,7 +112,7 @@
   r [P7b,P6b,P5a,P49,P38,P27,P16,P05] "[^M]*M[^M]*"
   r [P6c,P5b,P4a,P39,P28,P17,P06] "(S|MM|HHH)*"
 
-r :: (Fail.MonadFail m, MonadState s m, HasSAT s)
+r :: (Fail.MonadFail m, MonadSAT s m)
   => [Pos] -> String -> ReaderT (Map Pos Field) m ()
 r poss regexpStr = do
   fieldMap <- ask
diff --git a/examples/sudoku/Sudoku/Problem.hs b/examples/sudoku/Sudoku/Problem.hs
--- a/examples/sudoku/Sudoku/Problem.hs
+++ b/examples/sudoku/Sudoku/Problem.hs
@@ -8,7 +8,6 @@
 import Control.Applicative
 #endif
 import Control.Monad.Reader
-import Control.Monad.State
 import Data.Array (Array, (!))
 import qualified Data.Array as Array
 import Data.Word
@@ -25,7 +24,7 @@
                }
   deriving Show
 
-problem :: (Applicative m, MonadState s m, HasSAT s)
+problem :: (Applicative m, MonadSAT s m)
         => Array Index Word8 -> m Grid
 problem initValues = do
   cellArray <-  Array.listArray range
@@ -40,13 +39,13 @@
 
   return cellArray
 
-problem' :: (MonadState s m, HasSAT s) => ReaderT Env m ()
+problem' :: MonadSAT s m => ReaderT Env m ()
 problem' = do
   legalValues
   mapM_ allDifferent (subsquares ++ horizontal ++ vertical)
 
 -- | Assert that each cell must have one of the legal values.
-legalValues :: (MonadState s m, HasSAT s) => ReaderT Env m ()
+legalValues :: MonadSAT s m => ReaderT Env m ()
 legalValues = mapM_ legalValue . Array.elems =<< asks envCellArray
   where
     legalValue cell = do
@@ -54,8 +53,7 @@
       assert $ any (cell ===) values
 
 -- | Assert that each cell in a group must have a different value.
-allDifferent :: (MonadState s m, HasSAT s)
-             => [(Word8,Word8)] -> ReaderT Env m ()
+allDifferent :: MonadSAT s m => [(Word8,Word8)] -> ReaderT Env m ()
 allDifferent indices = do
   cellArray <- asks envCellArray
   let pairs = [ (cellArray ! a, cellArray ! b)
diff --git a/src/Ersatz/Bit.hs b/src/Ersatz/Bit.hs
--- a/src/Ersatz/Bit.hs
+++ b/src/Ersatz/Bit.hs
@@ -63,7 +63,7 @@
   | Mux !Bit !Bit !Bit
   | Not !Bit
   | Var !Literal
-  | Run ( forall m s . (MonadState s m, HasSAT s) => m Bit )
+  | Run ( forall m s . MonadSAT s m => m Bit )
   deriving (Typeable)
 
 instance Show Bit where
@@ -160,7 +160,7 @@
 
 -- | Assert claims that 'Bit' must be 'true' in any satisfying interpretation
 -- of the current problem.
-assert :: (MonadState s m, HasSAT s) => Bit -> m ()
+assert :: MonadSAT s m => Bit -> m ()
 assert (And bs) = Foldable.for_ bs assert
 -- the following (when switched on, False => True) produces extra clauses, why?
 assert (Not (And bs)) | False = do
@@ -171,7 +171,7 @@
   assertFormula (formulaLiteral l)
 
 -- | Convert a 'Bit' to a 'Literal'.
-runBit :: (MonadState s m, HasSAT s) => Bit -> m Literal
+runBit :: MonadSAT s m => Bit -> m Literal
 runBit (Not c) = negateLiteral `fmap` runBit c
 runBit (Var l) = return l
 runBit (Run action) = action >>= runBit
diff --git a/src/Ersatz/Problem.hs b/src/Ersatz/Problem.hs
--- a/src/Ersatz/Problem.hs
+++ b/src/Ersatz/Problem.hs
@@ -8,6 +8,7 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE Trustworthy #-}
+{-# LANGUAGE ConstraintKinds #-}
 
 {-# OPTIONS_HADDOCK not-home #-}
 #ifndef MIN_VERSION_lens
@@ -27,6 +28,7 @@
   -- * SAT
     SAT(SAT)
   , HasSAT(..)
+  , MonadSAT
   , runSAT, runSAT', dimacsSAT
   , literalExists
   , assertFormula
@@ -34,6 +36,7 @@
   -- * QSAT
   , QSAT(QSAT)
   , HasQSAT(..)
+  , MonadQSAT
   , runQSAT, runQSAT', qdimacsQSAT
   , literalForall
   -- * DIMACS pretty printing
@@ -77,6 +80,12 @@
 import Control.Monad.Identity
 #endif
 
+-- | Constraint synonym for types that carry a SAT state.
+type MonadSAT  s m = (HasSAT  s, MonadState s m)
+
+-- | Constraint synonym for types that carry a QSAT state.
+type MonadQSAT s m = (HasQSAT s, MonadState s m)
+
 ------------------------------------------------------------------------------
 -- SAT Problems
 ------------------------------------------------------------------------------
@@ -114,12 +123,12 @@
   def = SAT 1 (formulaLiteral literalTrue) HashMap.empty
 
 -- | Run a 'SAT'-generating state computation. Useful e.g. in ghci for
--- disambiguating the type of a 'MonadState', 'HasSAT' value.
+-- disambiguating the type of a 'MonadSAT' value.
 runSAT :: StateT SAT m a -> m (a, SAT)
 runSAT s = runStateT s def
 
 -- | Run a 'SAT'-generating state computation in the 'Identity' monad. Useful
--- e.g. in ghci for disambiguating the type of a 'MonadState', 'HasSAT' value.
+-- e.g. in ghci for disambiguating the type of a 'MonadSAT' value.
 runSAT' :: StateT SAT Identity a -> (a, SAT)
 runSAT' = runIdentity . runSAT
 
@@ -128,15 +137,15 @@
 dimacsSAT :: StateT SAT Identity a -> Lazy.ByteString
 dimacsSAT = toLazyByteString . dimacs . snd . runSAT'
 
-literalExists :: (MonadState s m, HasSAT s) => m Literal
+literalExists :: MonadSAT s m => m Literal
 literalExists = fmap Literal $ lastAtom <+= 1
 {-# INLINE literalExists #-}
 
-assertFormula :: (MonadState s m, HasSAT s) => Formula -> m ()
+assertFormula :: MonadSAT s m => Formula -> m ()
 assertFormula xs = formula <>= xs
 {-# INLINE assertFormula #-}
 
-generateLiteral :: (MonadState s m, HasSAT s) => a -> (Literal -> m ()) -> m Literal
+generateLiteral :: MonadSAT s m => a -> (Literal -> m ()) -> m Literal
 generateLiteral a f = do
   let sn = unsafePerformIO (makeStableName' a)
   use (stableMap.at sn) >>= \ ml -> case ml of
@@ -188,7 +197,7 @@
 qdimacsQSAT :: StateT QSAT Identity a -> Lazy.ByteString
 qdimacsQSAT = toLazyByteString . qdimacs . snd . runQSAT'
 
-literalForall :: (MonadState s m, HasQSAT s) => m Literal
+literalForall :: MonadQSAT s m => m Literal
 literalForall = do
    l <- lastAtom <+= 1
    universals.contains l .= True
diff --git a/src/Ersatz/Relation/Data.hs b/src/Ersatz/Relation/Data.hs
--- a/src/Ersatz/Relation/Data.hs
+++ b/src/Ersatz/Relation/Data.hs
@@ -12,7 +12,7 @@
 import Ersatz.Bit
 import Ersatz.Codec
 import Ersatz.Variable (exists)
-import Ersatz.Problem (HasSAT)
+import Ersatz.Problem (MonadSAT)
 
 import qualified Data.Array as A
 import Data.Array ( Array, Ix )
@@ -25,7 +25,7 @@
   decode s (Relation a) = decode s a
   encode a = Relation $ encode a
 
-relation :: ( Ix a, Ix b, MonadState s m, HasSAT s )
+relation :: ( Ix a, Ix b, MonadSAT s m )
          => ((a,b),(a,b)) -> m ( Relation a b )
 relation bnd = do
     pairs <- sequence $ do
@@ -36,7 +36,7 @@
     return $ build bnd pairs
 
 symmetric_relation ::
-  (HasSAT s, MonadState s m, Ix b) =>
+  (MonadSAT s m, Ix b) =>
   ((b, b), (b, b)) -> m (Relation b b)
 symmetric_relation bnd = do
     pairs <- sequence $ do
diff --git a/src/Ersatz/Relation/Op.hs b/src/Ersatz/Relation/Op.hs
--- a/src/Ersatz/Relation/Op.hs
+++ b/src/Ersatz/Relation/Op.hs
@@ -48,7 +48,7 @@
         ((_ ,bl),(_ ,br)) = bounds b
         bnd = ((ao,bl),(au,br))
     in  build bnd $ do
-          i @ (x,z) <- range bnd
+          i@(x,z) <- range bnd
           return (i, or $ do
                 y <- range ( al, ar )
                 return $ and [ a!(x,y), b!(y,z) ]
diff --git a/src/Ersatz/Relation/Prop.hs b/src/Ersatz/Relation/Prop.hs
--- a/src/Ersatz/Relation/Prop.hs
+++ b/src/Ersatz/Relation/Prop.hs
@@ -92,7 +92,7 @@
     x <- range ( a , c )
     return $ f deg $ do
         y <- range (b,d)
-        return $ r !(x,y)
+        return $ r ! (x,y)
 
 transitive :: ( Ix a )
            => Relation a a -> Bit
diff --git a/src/Ersatz/Variable.hs b/src/Ersatz/Variable.hs
--- a/src/Ersatz/Variable.hs
+++ b/src/Ersatz/Variable.hs
@@ -24,21 +24,20 @@
   ) where
 
 import Control.Monad
-import Control.Monad.State.Class
 import Ersatz.Internal.Literal
 import Ersatz.Problem
 import GHC.Generics
 
-exists :: (Variable a, MonadState s m, HasSAT s)  => m a
+exists :: (Variable a, MonadSAT s m)  => m a
 exists = literally literalExists
 
 #ifndef HLINT
-forall :: (Variable a, MonadState s m, HasQSAT s)  => m a
+forall :: (Variable a, MonadQSAT s m)  => m a
 forall = literally literalForall
 #endif
 
 class GVariable f where
-  gliterally :: (MonadState s m, HasSAT s) => m Literal -> m (f a)
+  gliterally :: MonadSAT s m => m Literal -> m (f a)
 
 instance GVariable U1 where
   gliterally _ = return U1
@@ -55,14 +54,14 @@
 -- | Instances for this class for product-like types can be automatically derived
 -- for any type that is an instance of 'Generic'.
 class Variable t where
-  literally :: (HasSAT s, MonadState s m) => m Literal -> m t
+  literally :: MonadSAT s m => m Literal -> m t
   default literally ::
-    (HasSAT s, MonadState s m, Generic t, GVariable (Rep t)) =>
+    (MonadSAT s m, Generic t, GVariable (Rep t)) =>
     m Literal -> m t
   literally = genericLiterally
 
 genericLiterally ::
-  (HasSAT s, MonadState s m, Generic t, GVariable (Rep t)) =>
+  (MonadSAT s m, Generic t, GVariable (Rep t)) =>
   m Literal -> m t
 genericLiterally = fmap to . gliterally
 
diff --git a/tests/Moore.hs b/tests/Moore.hs
--- a/tests/Moore.hs
+++ b/tests/Moore.hs
@@ -24,7 +24,6 @@
 import qualified Data.Array as A
 import System.Environment (getArgs)
 import Control.Monad ( void, when, forM )
-import Control.Monad.State
 
 main :: IO ( )
 main = do
@@ -43,9 +42,10 @@
      (Satisfied, Just g) -> do printA g ; return True
      _ -> do return False
 
-moore :: (MonadState s m, HasSAT s )
-      => Int -> Int -> Int -> Int
-      -> m (R.Relation Int Int)
+moore ::
+  MonadSAT s m =>
+  Int -> Int -> Int -> Int ->
+  m (R.Relation Int Int)
 moore d k n s = do
   -- g <- R.symmetric_relation ((0,0),(n-1,n-1))
   g <- periodic_relation s ((0,0),(n-1,n-1))
diff --git a/tests/Z001.hs b/tests/Z001.hs
--- a/tests/Z001.hs
+++ b/tests/Z001.hs
@@ -12,7 +12,6 @@
 import Data.Proxy
 import Data.List ( transpose )
 import Control.Monad ( replicateM, forM_ )
-import Control.Monad.State
 
 main = do
   (Satisfied, Just ms) <- solveWith anyminisat $ do
@@ -39,7 +38,7 @@
        $ m ++ encode [ replicate (d-1) 0 ++ [1] ]
 
 class Unknown a where
-  unknown :: (MonadState s m, HasSAT s) => m a
+  unknown :: MonadSAT s m => m a
 
 -- | square matrices
 newtype Matrix (dim::Nat)  a = Matrix [[a]]