diff --git a/.travis.yml b/.travis.yml
index bd42d46..d1c14d1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,7 @@
 #
 # For more information, see https://github.com/haskell-CI/haskell-ci
 #
-# version: 0.3.20190429
+# version: 0.3.20190521
 #
 # This file is patched:
 # - We install the typediff utility from its repoistory.
@@ -34,6 +34,9 @@ before_cache:
   - rm -rfv $CABALHOME/packages/head.hackage
 matrix:
   include:
+    - compiler: ghc-8.8.1
+      addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.8.1","cabal-install-3.0"]}}
+      env: GHCHEAD=true
     - compiler: ghc-8.6.5
       addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-8.6.5","cabal-install-2.4"]}}
     - compiler: ghc-8.6.4
@@ -99,6 +102,8 @@ matrix:
     - compiler: ghc-7.0.1
       addons: {"apt":{"sources":["hvr-ghc"],"packages":["ghc-7.0.1","cabal-install-2.4"]}}
       env: BATTERIES=NO
+  allow_failures:
+    - compiler: ghc-8.8.1
 before_install:
   - HC=$(echo "/opt/$CC/bin/ghc" | sed 's/-/\//')
   - HCPKG="$HC-pkg"
@@ -107,7 +112,7 @@ before_install:
   - CABALHOME=$HOME/.cabal
   # install typediff
   - mkdir -p $HOME/.local/bin
-  - curl -L https://github.com/haskell-compat/base-compat/releases/download/typediff-0.1.3/typediff > $HOME/.local/bin/typediff
+  - curl -L https://github.com/haskell-compat/base-compat/releases/download/typediff-0.1.4/typediff > $HOME/.local/bin/typediff
   - chmod +x $HOME/.local/bin/typediff
   - export PATH="/opt/ghc/bin:$CABALHOME/bin:$HOME/.local/bin:$PATH"
   - TOP=$(pwd)
@@ -115,24 +120,6 @@ before_install:
   - echo $HCNUMVER
   - CABAL="$CABAL -vnormal+nowrap+markoutput"
   - set -o pipefail
-  - |
-    echo 'function blue(s) { printf "\033[0;34m" s "\033[0m " }'           >> .colorful.awk
-    echo 'BEGIN { state = "output"; }'                                     >> .colorful.awk
-    echo '/^-----BEGIN CABAL OUTPUT-----$/ { state = "cabal" }'            >> .colorful.awk
-    echo '/^-----END CABAL OUTPUT-----$/ { state = "output" }'             >> .colorful.awk
-    echo '!/^(-----BEGIN CABAL OUTPUT-----|-----END CABAL OUTPUT-----)/ {' >> .colorful.awk
-    echo '  if (state == "cabal") {'                                       >> .colorful.awk
-    echo '    print blue($0)'                                              >> .colorful.awk
-    echo '  } else {'                                                      >> .colorful.awk
-    echo '    print $0'                                                    >> .colorful.awk
-    echo '  }'                                                             >> .colorful.awk
-    echo '}'                                                               >> .colorful.awk
-  - cat .colorful.awk
-  - |
-    color_cabal_output () {
-      awk -f $TOP/.colorful.awk
-    }
-  - echo text | color_cabal_output
 install:
   - ${CABAL} --version
   - echo "$(${HC} --version) [$(${HC} --print-project-git-commit-id 2> /dev/null || echo '?')]"
@@ -156,6 +143,18 @@ install:
     echo "  prefix: $CABALHOME"                         >> $CABALHOME/config
     echo "repository hackage.haskell.org"               >> $CABALHOME/config
     echo "  url: http://hackage.haskell.org/"           >> $CABALHOME/config
+  - |
+    if $GHCHEAD; 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 "   secure: True"                                                                >> $CABALHOME/config
+    echo "   root-keys: 07c59cb65787dedfaef5bd5f987ceb5f7e5ebf88b904bbd4c5cbdeb2ff71b740" >> $CABALHOME/config
+    echo "              2e8555dde16ebd8df076f1a8ef13b8f14c66bad8eafefd7d9e37d0ed711821fb" >> $CABALHOME/config
+    echo "              8f79fd2389ab2967354407ec852cbe73f2e8635793ac446d09461ffb99527f6e" >> $CABALHOME/config
+    echo "   key-threshold: 3"                                                            >> $CABALHOME/config
+    fi
   - cat $CABALHOME/config
   - rm -fv cabal.project cabal.project.local cabal.project.freeze
   - travis_retry ${CABAL} v2-update -v
@@ -173,15 +172,15 @@ install:
   - if [ -f "./base-compat/configure.ac" ]; then (cd "./base-compat" && autoreconf -i); fi
   - if [ -f "./base-compat-batteries/configure.ac" ]; then (cd "./base-compat-batteries" && autoreconf -i); fi
   - if [ -f "./check/configure.ac" ]; then (cd "./check" && autoreconf -i); fi
-  - ${CABAL} v2-freeze -w ${HC} ${TEST} ${BENCH} | color_cabal_output
+  - ${CABAL} v2-freeze -w ${HC} ${TEST} ${BENCH}
   - "cat cabal.project.freeze | sed -E 's/^(constraints: *| *)//' | sed 's/any.//'"
   - rm  cabal.project.freeze
-  - travis_wait ${CABAL} v2-build -w ${HC} ${TEST} ${BENCH} --dep -j2 all | color_cabal_output
-  - travis_wait ${CABAL} v2-build -w ${HC} --disable-tests --disable-benchmarks --dep -j2 all | color_cabal_output
+  - travis_wait ${CABAL} v2-build -w ${HC} ${TEST} ${BENCH} --dep -j2 all
+  - travis_wait ${CABAL} v2-build -w ${HC} --disable-tests --disable-benchmarks --dep -j2 all
 script:
   - DISTDIR=$(mktemp -d /tmp/dist-test.XXXX)
   # Packaging...
-  - ${CABAL} v2-sdist all | color_cabal_output
+  - ${CABAL} v2-sdist all
   # Unpacking...
   - mv dist-newstyle/sdist/*.tar.gz ${DISTDIR}/
   - cd ${DISTDIR} || false
@@ -199,21 +198,21 @@ script:
   - cat cabal.project.local || true
   # Building...
   # this builds all libraries and executables (without tests/benchmarks)
-  - ${CABAL} v2-build -w ${HC} --disable-tests --disable-benchmarks all | color_cabal_output
+  - ${CABAL} v2-build -w ${HC} --disable-tests --disable-benchmarks all
   # Building with tests and benchmarks...
   # build & run tests, build benchmarks
-  - ${CABAL} v2-build -w ${HC} ${TEST} ${BENCH} all | color_cabal_output
+  - ${CABAL} v2-build -w ${HC} ${TEST} ${BENCH} all
   # Testing...
-  - if [ $HCNUMVER -ge 70002 ] && [ $HCNUMVER -lt 70201 ]  ||  [ $HCNUMVER -ge 70202 ] && [ $HCNUMVER -lt 70401 ]  ||  [ $HCNUMVER -ge 70402 ] && [ $HCNUMVER -lt 70801 ]  ||  [ $HCNUMVER -ge 70802 ] ; then ${CABAL} v2-test -w ${HC} ${TEST} ${BENCH} all | color_cabal_output ; fi
+  - if [ $HCNUMVER -ge 70002 ] && [ $HCNUMVER -lt 70201 ]  ||  [ $HCNUMVER -ge 70202 ] && [ $HCNUMVER -lt 70401 ]  ||  [ $HCNUMVER -ge 70402 ] && [ $HCNUMVER -lt 70801 ]  ||  [ $HCNUMVER -ge 70802 ] ; then ${CABAL} v2-test -w ${HC} ${TEST} ${BENCH} all ; fi
   # cabal check...
   - (cd base-compat-* && ${CABAL} -vnormal check)
   - if [ ! "x$BATTERIES" = "xNO" ] ; then (cd base-compat-batteries-* && ${CABAL} -vnormal check) ; fi
   - if [ ! "x$BATTERIES" = "xNO" ] ; then (cd type-check-* && ${CABAL} -vnormal check) ; fi
   # haddock...
-  - ${CABAL} v2-haddock -w ${HC} ${TEST} ${BENCH} all | color_cabal_output
+  - ${CABAL} v2-haddock -w ${HC} ${TEST} ${BENCH} all
   # Building without installed constraints for packages in global-db...
   - rm -f cabal.project.local
-  - ${CABAL} v2-build -w ${HC} --disable-tests --disable-benchmarks all | color_cabal_output
+  - ${CABAL} v2-build -w ${HC} --disable-tests --disable-benchmarks all
 
 # REGENDATA ["--output=.travis.yml","--config=cabal.haskell-ci","cabal.project"]
 # EOF
diff --git a/base-compat-batteries/CHANGES.markdown b/base-compat-batteries/CHANGES.markdown
index 1cbda79..2c3f6a0 100644
--- a/base-compat-batteries/CHANGES.markdown
+++ b/base-compat-batteries/CHANGES.markdown
@@ -1,3 +1,36 @@
+## Changes in 0.11.0 [????.??.??]
+ - Reexport `MonadFail(fail)` from `Prelude.Compat` and `Control.Monad.Compat`.
+
+   Because `Prelude.Compat.fail` now corresponds to the `fail` from `MonadFail`
+   instead of `Monad`, some care is required to implement `Monad.fail` on
+   pre-8.8 versions of GHC. The following template is recommended:
+
+   ```haskell
+   import Prelude.Compat
+   #if !(MIN_VERSION_base(4,13,0))
+   import qualified Control.Monad
+   #endif
+
+   data Blah a = ...
+
+   instance Functor Blah where ...
+   instance Applicative Blah where ...
+
+   instance Monad Blah where
+     (>>=) = ...
+   #if !(MIN_VERSION_base(4,13,0))
+     fail = fail -- The RHS fail corresponds to MonadFail.fail,
+                 -- /not/ Monad.fail
+   #endif
+
+   instance MonadFail Blah where
+     fail = ...
+   ```
+
+ - This coincides with the `base-compat-???` release. Refer to the
+   [`base-compat` changelog](https://github.com/haskell-compat/base-compat/blob/master/base-compat/CHANGES.markdown#changes-in-????-????????)
+   for more details.
+
 ## Changes in 0.10.5 [2018.10.18]
  - This coincides with the `base-compat-0.10.5` release. Refer to the
    [`base-compat` changelog](https://github.com/haskell-compat/base-compat/blob/master/base-compat/CHANGES.markdown#changes-in-0105-20181018)
diff --git a/base-compat-batteries/base-compat-batteries.cabal b/base-compat-batteries/base-compat-batteries.cabal
index e18f57d..be1fedd 100644
--- a/base-compat-batteries/base-compat-batteries.cabal
+++ b/base-compat-batteries/base-compat-batteries.cabal
@@ -1,5 +1,5 @@
 name:             base-compat-batteries
-version:          0.10.5
+version:          0.11.0
 license:          MIT
 license-file:     LICENSE
 copyright:        (c) 2012-2018 Simon Hengel,
@@ -44,6 +44,7 @@ tested-with:        GHC == 7.0.*
                   , GHC == 8.2.*
                   , GHC == 8.4.*
                   , GHC == 8.6.*
+                  , GHC == 8.8.*
 extra-source-files: CHANGES.markdown, README.markdown
 
 source-repository head
@@ -56,7 +57,7 @@ library
       -Wall
   build-depends:
       base        >= 4.3 && < 5,
-      base-compat == 0.10.5
+      base-compat == 0.11.0
   if !impl(ghc >= 7.8)
     build-depends:
       tagged >= 0.8.5 && < 0.9
diff --git a/base-compat-batteries/src/Control/Monad/Compat.hs b/base-compat-batteries/src/Control/Monad/Compat.hs
index 351f434..584e676 100644
--- a/base-compat-batteries/src/Control/Monad/Compat.hs
+++ b/base-compat-batteries/src/Control/Monad/Compat.hs
@@ -1,6 +1,8 @@
 {-# LANGUAGE CPP, NoImplicitPrelude, PackageImports #-}
 module Control.Monad.Compat (
   module Base
-  ) where
+, fail
+) where
 
-import "base-compat" Control.Monad.Compat as Base
+import "base-compat" Control.Monad.Compat as Base hiding (fail)
+import Control.Monad.Fail (fail)
diff --git a/base-compat-batteries/src/Prelude/Compat.hs b/base-compat-batteries/src/Prelude/Compat.hs
index ec77756..0c5034f 100644
--- a/base-compat-batteries/src/Prelude/Compat.hs
+++ b/base-compat-batteries/src/Prelude/Compat.hs
@@ -2,12 +2,17 @@
 module Prelude.Compat (
   module Base
 #if !(MIN_VERSION_base(4,9,0))
+, Fail.MonadFail(Fail.fail)
 , Semi.Semigroup((Semi.<>))
 #endif
 ) where
 
 import "base-compat" Prelude.Compat as Base
+#if !(MIN_VERSION_base(4,9,0))
+  hiding (fail)
+#endif
 
 #if !(MIN_VERSION_base(4,9,0))
+import "fail"       Control.Monad.Fail as Fail
 import "semigroups" Data.Semigroup as Semi
 #endif
diff --git a/base-compat/CHANGES.markdown b/base-compat/CHANGES.markdown
index 8532071..721dd43 100644
--- a/base-compat/CHANGES.markdown
+++ b/base-compat/CHANGES.markdown
@@ -1,3 +1,41 @@
+## Changes in 0.11.0 [????.??.??]
+ - Sync with `base-4.13`/GHC 8.8
+ - Backport `MonadFail(fail)` to `Prelude.Compat` and `Control.Monad.Compat`.
+
+   Because `Prelude.Compat.fail` now corresponds to the `fail` from `MonadFail`
+   instead of `Monad`, some care is required to implement `Monad.fail` on
+   pre-8.8 versions of GHC. The following template is recommended:
+
+   ```haskell
+   import Prelude.Compat
+   #if !(MIN_VERSION_base(4,13,0))
+   import qualified Control.Monad
+   #endif
+
+   data Blah a = ...
+
+   instance Functor Blah where ...
+   instance Applicative Blah where ...
+
+   instance Monad Blah where
+     (>>=) = ...
+   #if !(MIN_VERSION_base(4,13,0))
+     fail = fail -- The RHS fail corresponds to MonadFail.fail,
+                 -- /not/ Monad.fail
+   #endif
+
+   instance MonadFail Blah where
+     fail = ...
+   ```
+
+   Note that the `MonadFail` class has only been in `base` since
+   `base-4.9`/GHC 8.0, so accordingly, this can only be backported back
+   to GHC 8.0. If you wish to have a version of
+   `Prelude.Compat`/`Control.Monad.Compat` that backports
+   `MonadFail` to older GHCs (by conditionally depending on the `fail`
+   library), use the `Prelude.Compat`/`Control.Monad.Compat` modules from the
+   `base-compat-batteries` package.
+
 ## Changes in 0.10.5 [2018.10.18]
  - Enable `BangPatterns` in `Prelude.Compat`.
 
diff --git a/base-compat/README.markdown b/base-compat/README.markdown
index 7d0a2ad..fc4b927 100644
--- a/base-compat/README.markdown
+++ b/base-compat/README.markdown
@@ -302,6 +302,8 @@ on, paired with the things that each library backports:
 
 ## Supported versions of GHC/`base`
 
+ * `ghc-8.8.1`  / `base-4.13.0.0`
+ * `ghc-8.6.5`  / `base-4.12.0.0`
  * `ghc-8.6.4`  / `base-4.12.0.0`
  * `ghc-8.6.3`  / `base-4.12.0.0`
  * `ghc-8.6.2`  / `base-4.12.0.0`
diff --git a/base-compat/base-compat.cabal b/base-compat/base-compat.cabal
index e9f27be..414074c 100644
--- a/base-compat/base-compat.cabal
+++ b/base-compat/base-compat.cabal
@@ -1,5 +1,5 @@
 name:             base-compat
-version:          0.10.5
+version:          0.11.0
 license:          MIT
 license-file:     LICENSE
 copyright:        (c) 2012-2018 Simon Hengel,
@@ -53,6 +53,7 @@ tested-with:        GHC == 7.0.*
                   , GHC == 8.2.*
                   , GHC == 8.4.*
                   , GHC == 8.6.*
+                  , GHC == 8.8.*
 extra-source-files: CHANGES.markdown, README.markdown
 
 source-repository head
diff --git a/base-compat/src/Control/Monad/Compat.hs b/base-compat/src/Control/Monad/Compat.hs
index 543c19a..e6b25d1 100644
--- a/base-compat/src/Control/Monad/Compat.hs
+++ b/base-compat/src/Control/Monad/Compat.hs
@@ -1,7 +1,11 @@
 {-# LANGUAGE CPP, NoImplicitPrelude #-}
 module Control.Monad.Compat (
   module Base
-, Monad(..)
+, Monad
+#if MIN_VERSION_base(4,9,0)
+, MonadFail
+#endif
+, fail
 , MonadPlus(..)
 #if !(MIN_VERSION_base(4,8,0))
 , foldM
@@ -31,7 +35,8 @@ module Control.Monad.Compat (
 ) where
 
 #if MIN_VERSION_base(4,9,0)
-import Control.Monad as Base
+import Control.Monad as Base hiding (fail)
+import Control.Monad.Fail as Base
 #else
 import Control.Monad as Base hiding (
     forever
diff --git a/base-compat/src/Prelude/Compat.hs b/base-compat/src/Prelude/Compat.hs
index 8956cb5..365d66d 100644
--- a/base-compat/src/Prelude/Compat.hs
+++ b/base-compat/src/Prelude/Compat.hs
@@ -235,6 +235,9 @@ module Prelude.Compat (
 , Functor
 , Integral
 , Monad
+#if MIN_VERSION_base(4,9,0)
+, MonadFail
+#endif
 , Monoid
 , Num (fromInteger)
 , Ord
@@ -274,10 +277,14 @@ module Prelude.Compat (
 
 #if MIN_VERSION_base(4,9,0)
 
-import Prelude as Base
-# if MIN_VERSION_base(4,10,0) && !(MIN_VERSION_base(4,12,0))
-  hiding (($!))
+import Prelude as Base hiding (
+# if !(MIN_VERSION_base(4,13,0))
+    fail
+#  if MIN_VERSION_base(4,10,0) && !(MIN_VERSION_base(4,12,0))
+  , ($!)
+#  endif
 # endif
+  )
 
 #else
 
@@ -322,6 +329,10 @@ import Data.Word
 import Data.Semigroup as Base (Semigroup((<>)))
 #endif
 
+#if MIN_VERSION_base(4,9,0) && !(MIN_VERSION_base(4,13,0))
+import Control.Monad.Fail as Base (MonadFail(fail))
+#endif
+
 #if MIN_VERSION_base(4,10,0) && !(MIN_VERSION_base(4,12,0))
 import GHC.Exts (TYPE)
 #endif
diff --git a/cabal.haskell-ci b/cabal.haskell-ci
index d9867aa..88a96ac 100644
--- a/cabal.haskell-ci
+++ b/cabal.haskell-ci
@@ -6,3 +6,5 @@ env:            7.0.1:BATTERIES=NO,
 -- TODO: Have `BATTERIES=NO` imply no tests
 tests:          (>=7.0.2 && <7.2.1) || (>=7.2.2 && <7.4.1) || (>=7.4.2 && <7.8.1) || >=7.8.2
 travis-patches: travis.yml.patch
+-- travis_wait interacts poorly with color_cabal_output
+color:          False
diff --git a/check/lib/Util.hs b/check/lib/Util.hs
index b932e8f..355208c 100644
--- a/check/lib/Util.hs
+++ b/check/lib/Util.hs
@@ -115,7 +115,8 @@ normalizeSignatures
             -- something that we shouldn't.
             --
             _ <- P.choice
-                [ P.try (P.string "ghc-prim")
+                [ P.try (P.string "fail")
+                , P.try (P.string "ghc-prim")
                 , P.try (P.string "semigroups")
                 ]
 
diff --git a/check/type-check.cabal b/check/type-check.cabal
index 8803013..a438e0d 100644
--- a/check/type-check.cabal
+++ b/check/type-check.cabal
@@ -7,7 +7,7 @@ version:             0.1.0
 synopsis:            Checks that exported type signatures match what's expected
 description:
   Checks that exported type signatures match what's expected.
-  
+
 
 author:              Simon Hengel <sol@typeful.net>,
                      João Cristóvão <jmacristovao@gmail.com>,
@@ -38,6 +38,7 @@ tested-with:        GHC == 7.0.*
                   , GHC == 8.2.*
                   , GHC == 8.4.*
                   , GHC == 8.6.*
+                  , GHC == 8.8.*
 library
   exposed-modules:
       TypeDump
@@ -75,7 +76,7 @@ executable dumptypes
 
 -- Run with
 -- (cd check && cabal new-run dumpindex Control.Monad.Compat)
--- 
+--
 executable dumpindex
   default-language: Haskell2010
   hs-source-dirs: exes
diff --git a/check/types/Control.Monad.Compat.types b/check/types/Control.Monad.Compat.types
index d64337d..9cfce40 100644
--- a/check/types/Control.Monad.Compat.types
+++ b/check/types/Control.Monad.Compat.types
@@ -5,7 +5,7 @@
 (>>=) :: Monad m => m a -> (a -> m b) -> m b
 (>>) :: Monad m => m a -> m b -> m b
 ap :: Monad m => m (a -> b) -> m a -> m b
-fail :: Monad m => GHC.Base.String -> m a
+fail :: MonadFail m => GHC.Base.String -> m a
 filterM :: GHC.Base.Applicative m =>    (a -> m GHC.Types.Bool) -> [a] -> m [a]
 fmap :: Functor f => (a -> b) -> f a -> f b
 foldM :: (Data.Foldable.Foldable t, Monad m) =>    (b -> a -> m b) -> b -> t a -> m b
@@ -23,17 +23,17 @@ liftM5 :: Monad m =>    (a1 -> a2 -> a3 -> a4 -> a5 -> r)    -> m a1 -> m a2 ->
 mapAndUnzipM :: GHC.Base.Applicative m => (a -> m (b, c)) -> [a] -> m ([b], [c])
 mapM :: (Data.Traversable.Traversable t, Monad m) =>    (a -> m b) -> t a -> m (t b)
 mapM_ :: (Data.Foldable.Foldable t, Monad m) => (a -> m b) -> t a -> m ()
-mfilter :: MonadPlus m => (a -> GHC.Types.Bool) -> m a -> m a
+mfilter :: MonadPlus m =>    (a -> GHC.Types.Bool) -> m a -> m a
 mplus :: MonadPlus m => m a -> m a -> m a
 msum :: (Data.Foldable.Foldable t, MonadPlus m) => t (m a) -> m a
 mzero :: MonadPlus m => m a
-replicateM :: GHC.Base.Applicative m => GHC.Types.Int -> m a -> m [a]
-replicateM_ :: GHC.Base.Applicative m => GHC.Types.Int -> m a -> m ()
+replicateM :: GHC.Base.Applicative m =>    GHC.Types.Int -> m a -> m [a]
+replicateM_ :: GHC.Base.Applicative m =>    GHC.Types.Int -> m a -> m ()
 return :: Monad m => a -> m a
 sequence :: (Data.Traversable.Traversable t, Monad m) => t (m a) -> m (t a)
 sequence_ :: (Data.Foldable.Foldable t, Monad m) => t (m a) -> m ()
-unless :: GHC.Base.Applicative f => GHC.Types.Bool -> f () -> f ()
+unless :: GHC.Base.Applicative f =>    GHC.Types.Bool -> f () -> f ()
 void :: Functor f => f a -> f ()
-when :: GHC.Base.Applicative f => GHC.Types.Bool -> f () -> f ()
+when :: GHC.Base.Applicative f =>    GHC.Types.Bool -> f () -> f ()
 zipWithM :: GHC.Base.Applicative m => (a -> b -> m c) -> [a] -> [b] -> m [c]
 zipWithM_ :: GHC.Base.Applicative m => (a -> b -> m c) -> [a] -> [b] -> m ()
diff --git a/check/types/Data.Foldable.Compat.types b/check/types/Data.Foldable.Compat.types
index e39ff89..0458ed4 100644
--- a/check/types/Data.Foldable.Compat.types
+++ b/check/types/Data.Foldable.Compat.types
@@ -1,11 +1,11 @@
-all :: Foldable t => (a -> GHC.Types.Bool) -> t a -> GHC.Types.Bool
-and :: Foldable t => t GHC.Types.Bool -> GHC.Types.Bool
-any :: Foldable t => (a -> GHC.Types.Bool) -> t a -> GHC.Types.Bool
+all :: Foldable t =>    (a -> GHC.Types.Bool)    -> t a -> GHC.Types.Bool
+and :: Foldable t =>    t GHC.Types.Bool -> GHC.Types.Bool
+any :: Foldable t =>    (a -> GHC.Types.Bool)    -> t a -> GHC.Types.Bool
 asum :: (Foldable t, GHC.Base.Alternative f) => t (f a) -> f a
 concat :: Foldable t => t [a] -> [a]
 concatMap :: Foldable t => (a -> [b]) -> t a -> [b]
-elem :: (Foldable t, GHC.Classes.Eq a) => a -> t a -> GHC.Types.Bool
-find :: Foldable t => (a -> GHC.Types.Bool) -> t a -> GHC.Base.Maybe a
+elem :: (Foldable t, GHC.Classes.Eq a) =>    a -> t a -> GHC.Types.Bool
+find :: Foldable t =>    (a -> GHC.Types.Bool) -> t a -> GHC.Maybe.Maybe a
 fold :: (Foldable t, GHC.Base.Monoid m) => t m -> m
 foldl :: Foldable t => (b -> a -> b) -> b -> t a -> b
 foldl' :: Foldable t => (b -> a -> b) -> b -> t a -> b
@@ -21,13 +21,13 @@ forM_ :: (Foldable t, GHC.Base.Monad m) => t a -> (a -> m b) -> m ()
 length :: Foldable t => t a -> GHC.Types.Int
 mapM_ :: (Foldable t, GHC.Base.Monad m) => (a -> m b) -> t a -> m ()
 maximum :: (Foldable t, GHC.Classes.Ord a) => t a -> a
-maximumBy :: Foldable t => (a -> a -> GHC.Types.Ordering) -> t a -> a
+maximumBy :: Foldable t =>    (a -> a -> GHC.Types.Ordering) -> t a -> a
 minimum :: (Foldable t, GHC.Classes.Ord a) => t a -> a
-minimumBy :: Foldable t => (a -> a -> GHC.Types.Ordering) -> t a -> a
+minimumBy :: Foldable t =>    (a -> a -> GHC.Types.Ordering) -> t a -> a
 msum :: (Foldable t, GHC.Base.MonadPlus m) => t (m a) -> m a
-notElem :: (Foldable t, GHC.Classes.Eq a) => a -> t a -> GHC.Types.Bool
+notElem :: (Foldable t, GHC.Classes.Eq a) =>    a -> t a -> GHC.Types.Bool
 null :: Foldable t => t a -> GHC.Types.Bool
-or :: Foldable t => t GHC.Types.Bool -> GHC.Types.Bool
+or :: Foldable t =>    t GHC.Types.Bool -> GHC.Types.Bool
 product :: (Foldable t, GHC.Num.Num a) => t a -> a
 sequence_ :: (Foldable t, GHC.Base.Monad m) => t (m a) -> m ()
 sequenceA_ :: (Foldable t, GHC.Base.Applicative f) => t (f a) -> f ()
diff --git a/check/types/Data.List.Compat.types b/check/types/Data.List.Compat.types
index d3e9cc1..f9b61a4 100644
--- a/check/types/Data.List.Compat.types
+++ b/check/types/Data.List.Compat.types
@@ -1,9 +1,9 @@
 (!!) :: [a] -> GHC.Types.Int -> a
 (\\) :: GHC.Classes.Eq a => [a] -> [a] -> [a]
 (++) :: [a] -> [a] -> [a]
-all :: Data.Foldable.Foldable t =>    (a -> GHC.Types.Bool) -> t a -> GHC.Types.Bool
-and :: Data.Foldable.Foldable t => t GHC.Types.Bool -> GHC.Types.Bool
-any :: Data.Foldable.Foldable t =>    (a -> GHC.Types.Bool) -> t a -> GHC.Types.Bool
+all :: Data.Foldable.Foldable t =>    (a -> GHC.Types.Bool)    -> t a -> GHC.Types.Bool
+and :: Data.Foldable.Foldable t =>    t GHC.Types.Bool -> GHC.Types.Bool
+any :: Data.Foldable.Foldable t =>    (a -> GHC.Types.Bool)    -> t a -> GHC.Types.Bool
 break :: (a -> GHC.Types.Bool) -> [a] -> ([a], [a])
 concat :: Data.Foldable.Foldable t => t [a] -> [a]
 concatMap :: Data.Foldable.Foldable t => (a -> [b]) -> t a -> [b]
@@ -15,12 +15,12 @@ drop :: GHC.Types.Int -> [a] -> [a]
 dropWhile :: (a -> GHC.Types.Bool) -> [a] -> [a]
 dropWhileEnd :: (a -> GHC.Types.Bool) -> [a] -> [a]
 elem :: (Data.Foldable.Foldable t, GHC.Classes.Eq a) =>    a -> t a -> GHC.Types.Bool
-elemIndex :: GHC.Classes.Eq a => a -> [a] -> GHC.Base.Maybe GHC.Types.Int
-elemIndices :: GHC.Classes.Eq a => a -> [a] -> [GHC.Types.Int]
+elemIndex :: GHC.Classes.Eq a =>    a -> [a] -> GHC.Maybe.Maybe GHC.Types.Int
+elemIndices :: GHC.Classes.Eq a =>    a -> [a] -> [GHC.Types.Int]
 filter :: (a -> GHC.Types.Bool) -> [a] -> [a]
-find :: Data.Foldable.Foldable t =>    (a -> GHC.Types.Bool) -> t a -> GHC.Base.Maybe a
-findIndex :: (a -> GHC.Types.Bool) -> [a] -> GHC.Base.Maybe GHC.Types.Int
-findIndices :: (a -> GHC.Types.Bool) -> [a] -> [GHC.Types.Int]
+find :: Data.Foldable.Foldable t =>    (a -> GHC.Types.Bool) -> t a -> GHC.Maybe.Maybe a
+findIndex :: (a -> GHC.Types.Bool)    -> [a] -> GHC.Maybe.Maybe GHC.Types.Int
+findIndices :: (a -> GHC.Types.Bool)    -> [a] -> [GHC.Types.Int]
 foldl :: Data.Foldable.Foldable t => (b -> a -> b) -> b -> t a -> b
 foldl' :: Data.Foldable.Foldable t => (b -> a -> b) -> b -> t a -> b
 foldl1 :: Data.Foldable.Foldable t => (a -> a -> a) -> t a -> a
@@ -44,28 +44,28 @@ intercalate :: [a] -> [[a]] -> [a]
 intersect :: GHC.Classes.Eq a => [a] -> [a] -> [a]
 intersectBy :: (a -> a -> GHC.Types.Bool) -> [a] -> [a] -> [a]
 intersperse :: a -> [a] -> [a]
-isInfixOf :: GHC.Classes.Eq a => [a] -> [a] -> GHC.Types.Bool
-isPrefixOf :: GHC.Classes.Eq a => [a] -> [a] -> GHC.Types.Bool
-isSubsequenceOf :: GHC.Classes.Eq a => [a] -> [a] -> GHC.Types.Bool
-isSuffixOf :: GHC.Classes.Eq a => [a] -> [a] -> GHC.Types.Bool
+isInfixOf :: GHC.Classes.Eq a =>    [a] -> [a] -> GHC.Types.Bool
+isPrefixOf :: GHC.Classes.Eq a =>    [a] -> [a] -> GHC.Types.Bool
+isSubsequenceOf :: GHC.Classes.Eq a =>    [a] -> [a] -> GHC.Types.Bool
+isSuffixOf :: GHC.Classes.Eq a =>    [a] -> [a] -> GHC.Types.Bool
 iterate :: (a -> a) -> a -> [a]
 iterate' :: (a -> a) -> a -> [a]
 last :: [a] -> a
 length :: Data.Foldable.Foldable t => t a -> GHC.Types.Int
 lines :: GHC.Base.String -> [GHC.Base.String]
-lookup :: GHC.Classes.Eq a => a -> [(a, b)] -> GHC.Base.Maybe b
+lookup :: GHC.Classes.Eq a =>    a -> [(a, b)] -> GHC.Maybe.Maybe b
 map :: (a -> b) -> [a] -> [b]
 mapAccumL :: Data.Traversable.Traversable t =>    (a -> b -> (a, c)) -> a -> t b -> (a, t c)
 mapAccumR :: Data.Traversable.Traversable t =>    (a -> b -> (a, c)) -> a -> t b -> (a, t c)
-maximum :: (Data.Foldable.Foldable t, GHC.Classes.Ord a) => t a -> a
+maximum :: (Data.Foldable.Foldable t, GHC.Classes.Ord a) =>    t a -> a
 maximumBy :: Data.Foldable.Foldable t =>    (a -> a -> GHC.Types.Ordering) -> t a -> a
-minimum :: (Data.Foldable.Foldable t, GHC.Classes.Ord a) => t a -> a
+minimum :: (Data.Foldable.Foldable t, GHC.Classes.Ord a) =>    t a -> a
 minimumBy :: Data.Foldable.Foldable t =>    (a -> a -> GHC.Types.Ordering) -> t a -> a
 notElem :: (Data.Foldable.Foldable t, GHC.Classes.Eq a) =>    a -> t a -> GHC.Types.Bool
 nub :: GHC.Classes.Eq a => [a] -> [a]
 nubBy :: (a -> a -> GHC.Types.Bool) -> [a] -> [a]
 null :: Data.Foldable.Foldable t => t a -> GHC.Types.Bool
-or :: Data.Foldable.Foldable t => t GHC.Types.Bool -> GHC.Types.Bool
+or :: Data.Foldable.Foldable t =>    t GHC.Types.Bool -> GHC.Types.Bool
 partition :: (a -> GHC.Types.Bool) -> [a] -> ([a], [a])
 permutations :: [a] -> [[a]]
 product :: (Data.Foldable.Foldable t, GHC.Num.Num a) => t a -> a
@@ -82,7 +82,7 @@ sortBy :: (a -> a -> GHC.Types.Ordering) -> [a] -> [a]
 sortOn :: GHC.Classes.Ord b => (a -> b) -> [a] -> [a]
 span :: (a -> GHC.Types.Bool) -> [a] -> ([a], [a])
 splitAt :: GHC.Types.Int -> [a] -> ([a], [a])
-stripPrefix :: GHC.Classes.Eq a => [a] -> [a] -> GHC.Base.Maybe [a]
+stripPrefix :: GHC.Classes.Eq a =>    [a] -> [a] -> GHC.Maybe.Maybe [a]
 subsequences :: [a] -> [[a]]
 sum :: (Data.Foldable.Foldable t, GHC.Num.Num a) => t a -> a
 tail :: [a] -> [a]
@@ -90,8 +90,8 @@ tails :: [a] -> [[a]]
 take :: GHC.Types.Int -> [a] -> [a]
 takeWhile :: (a -> GHC.Types.Bool) -> [a] -> [a]
 transpose :: [[a]] -> [[a]]
-uncons :: [a] -> GHC.Base.Maybe (a, [a])
-unfoldr :: (b -> GHC.Base.Maybe (a, b)) -> b -> [a]
+uncons :: [a] -> GHC.Maybe.Maybe (a, [a])
+unfoldr :: (b -> GHC.Maybe.Maybe (a, b)) -> b -> [a]
 union :: GHC.Classes.Eq a => [a] -> [a] -> [a]
 unionBy :: (a -> a -> GHC.Types.Bool) -> [a] -> [a] -> [a]
 unlines :: [GHC.Base.String] -> GHC.Base.String
diff --git a/check/types/Data.Monoid.Compat.types b/check/types/Data.Monoid.Compat.types
index 3aa9309..069fd91 100644
--- a/check/types/Data.Monoid.Compat.types
+++ b/check/types/Data.Monoid.Compat.types
@@ -1,18 +1,18 @@
-(<>) :: Data.Semigroup.Semigroup a => a -> a -> a
+(<>) :: GHC.Base.Semigroup a => a -> a -> a
 All :: GHC.Types.Bool -> All
 Any :: GHC.Types.Bool -> Any
 appEndo :: Endo a -> a -> a
 Dual :: a -> Dual a
 Endo :: (a -> a) -> Endo a
-First :: GHC.Base.Maybe a -> First a
+First :: GHC.Maybe.Maybe a -> First a
 getAll :: All -> GHC.Types.Bool
 getAny :: Any -> GHC.Types.Bool
 getDual :: Dual a -> a
-getFirst :: First a -> GHC.Base.Maybe a
-getLast :: Last a -> GHC.Base.Maybe a
+getFirst :: First a -> GHC.Maybe.Maybe a
+getLast :: Last a -> GHC.Maybe.Maybe a
 getProduct :: Product a -> a
 getSum :: Sum a -> a
-Last :: GHC.Base.Maybe a -> Last a
+Last :: GHC.Maybe.Maybe a -> Last a
 mappend :: Monoid a => a -> a -> a
 mconcat :: Monoid a => [a] -> a
 mempty :: Monoid a => a
diff --git a/check/types/Prelude.Compat.types b/check/types/Prelude.Compat.types
index ddbc9f3..bcc5bf3 100644
--- a/check/types/Prelude.Compat.types
+++ b/check/types/Prelude.Compat.types
@@ -68,7 +68,7 @@ errorWithoutStackTrace :: [Char] -> a
 even :: Integral a => a -> Bool
 exp :: Floating a => a -> a
 exponent :: RealFloat a => a -> Int
-fail :: Monad m => String -> m a
+fail :: MonadFail m => String -> m a
 False :: Bool
 filter :: (a -> Bool) -> [a] -> [a]
 flip :: (a -> b -> c) -> b -> a -> c
diff --git a/travis.yml.patch b/travis.yml.patch
index 6ae9a0d..1e2d221 100644
--- a/travis.yml.patch
+++ b/travis.yml.patch
@@ -1,10 +1,10 @@
 diff --git a/.travis.yml b/.travis.yml
-index 0133546..d677f11 100644
+index 7f5a7b2..d1c14d1 100644
 --- a/.travis.yml
 +++ b/.travis.yml
 @@ -6,6 +6,14 @@
  #
- # version: 0.3.20190418
+ # version: 0.3.20190521
  #
 +# This file is patched:
 +# - We install the typediff utility from its repoistory.
@@ -17,20 +17,29 @@ index 0133546..d677f11 100644
  language: c
  dist: xenial
  git:
-@@ -96,7 +104,11 @@ before_install:
+@@ -102,7 +110,11 @@ before_install:
    - unset CC
    - CABAL=/opt/ghc/bin/cabal
    - CABALHOME=$HOME/.cabal
 -  - export PATH="$CABALHOME/bin:$PATH"
 +  # install typediff
 +  - mkdir -p $HOME/.local/bin
-+  - curl -L https://github.com/haskell-compat/base-compat/releases/download/typediff-0.1.3/typediff > $HOME/.local/bin/typediff
++  - curl -L https://github.com/haskell-compat/base-compat/releases/download/typediff-0.1.4/typediff > $HOME/.local/bin/typediff
 +  - chmod +x $HOME/.local/bin/typediff
 +  - export PATH="/opt/ghc/bin:$CABALHOME/bin:$HOME/.local/bin:$PATH"
    - TOP=$(pwd)
    - HCNUMVER=$(( $(${HC} --numeric-version|sed -E 's/([0-9]+)\.([0-9]+)\.([0-9]+).*/\1 * 10000 + \2 * 100 + \3/') ))
    - echo $HCNUMVER
-@@ -150,8 +162,7 @@ install:
+@@ -134,7 +146,7 @@ install:
+   - |
+     if $GHCHEAD; 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 "   secure: True"                                                                >> $CABALHOME/config
+@@ -151,8 +163,7 @@ install:
    - touch cabal.project
    - |
      echo 'packages: "./base-compat"' >> cabal.project
@@ -39,19 +48,19 @@ index 0133546..d677f11 100644
 +    if [ ! "x$BATTERIES" = "xNO" ] ; then (echo 'packages: "./base-compat-batteries"' >> cabal.project; echo 'packages: "./check"' >> cabal.project) ; fi
    - |
      echo "write-ghc-environment-files: always" >> cabal.project
-   - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | grep -vE -- '^(base-compat|base-compat-batteries|type-check)$' | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
-@@ -163,8 +174,8 @@ install:
-   - ${CABAL} v2-freeze -w ${HC} ${TEST} ${BENCH} | color_cabal_output
+   - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(base-compat|base-compat-batteries|type-check)$' || true) | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
+@@ -164,8 +175,8 @@ install:
+   - ${CABAL} v2-freeze -w ${HC} ${TEST} ${BENCH}
    - "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 -w ${HC} --disable-tests --disable-benchmarks --dep -j2 all | color_cabal_output
-+  - travis_wait ${CABAL} v2-build -w ${HC} ${TEST} ${BENCH} --dep -j2 all | color_cabal_output
-+  - travis_wait ${CABAL} v2-build -w ${HC} --disable-tests --disable-benchmarks --dep -j2 all | color_cabal_output
+-  - ${CABAL} v2-build -w ${HC} ${TEST} ${BENCH} --dep -j2 all
+-  - ${CABAL} v2-build -w ${HC} --disable-tests --disable-benchmarks --dep -j2 all
++  - travis_wait ${CABAL} v2-build -w ${HC} ${TEST} ${BENCH} --dep -j2 all
++  - travis_wait ${CABAL} v2-build -w ${HC} --disable-tests --disable-benchmarks --dep -j2 all
  script:
    - DISTDIR=$(mktemp -d /tmp/dist-test.XXXX)
    # Packaging...
-@@ -178,8 +189,7 @@ script:
+@@ -179,8 +190,7 @@ script:
    - touch cabal.project
    - |
      echo 'packages: "base-compat-*/*.cabal"' >> cabal.project
@@ -60,9 +69,9 @@ index 0133546..d677f11 100644
 +    if [ ! "x$BATTERIES" = "xNO" ] ; then (echo 'packages: "base-compat-batteries-*/*.cabal"' >> cabal.project; echo 'packages: "type-check-*/*.cabal"' >> cabal.project) ; fi
    - |
      echo "write-ghc-environment-files: always" >> cabal.project
-   - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | grep -vE -- '^(base-compat|base-compat-batteries|type-check)$' | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
-@@ -195,8 +205,8 @@ script:
-   - if [ $HCNUMVER -ge 70002 ] && [ $HCNUMVER -lt 70201 ]  ||  [ $HCNUMVER -ge 70202 ] && [ $HCNUMVER -lt 70401 ]  ||  [ $HCNUMVER -ge 70402 ] ; then ${CABAL} v2-test -w ${HC} ${TEST} ${BENCH} all | color_cabal_output ; fi
+   - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(base-compat|base-compat-batteries|type-check)$' || true) | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
+@@ -196,8 +206,8 @@ script:
+   - if [ $HCNUMVER -ge 70002 ] && [ $HCNUMVER -lt 70201 ]  ||  [ $HCNUMVER -ge 70202 ] && [ $HCNUMVER -lt 70401 ]  ||  [ $HCNUMVER -ge 70402 ] && [ $HCNUMVER -lt 70801 ]  ||  [ $HCNUMVER -ge 70802 ] ; then ${CABAL} v2-test -w ${HC} ${TEST} ${BENCH} all ; fi
    # cabal check...
    - (cd base-compat-* && ${CABAL} -vnormal check)
 -  - (cd base-compat-batteries-* && ${CABAL} -vnormal check)
@@ -70,5 +79,5 @@ index 0133546..d677f11 100644
 +  - if [ ! "x$BATTERIES" = "xNO" ] ; then (cd base-compat-batteries-* && ${CABAL} -vnormal check) ; fi
 +  - if [ ! "x$BATTERIES" = "xNO" ] ; then (cd type-check-* && ${CABAL} -vnormal check) ; fi
    # haddock...
-   - ${CABAL} v2-haddock -w ${HC} ${TEST} ${BENCH} all | color_cabal_output
+   - ${CABAL} v2-haddock -w ${HC} ${TEST} ${BENCH} all
    # Building without installed constraints for packages in global-db...