Update .travis.yml etc

Author: phadej

.stylish-haskell.yaml

@@ -11,6 +11,7 @@ steps:
   - trailing_whitespace: {}
 columns: 80
 language_extensions:
+  - DataKinds
   - EmptyCase
   - ExplicitForAll
   - FlexibleContexts

.travis.yml

@@ -4,7 +4,7 @@
 #
 # For more information, see https://github.com/haskell-CI/haskell-ci
 #
-# version: 0.9.20200325
+# version: 0.9.20200326
 #
 version: ~> 1.0
 language: c
@@ -116,6 +116,8 @@ install:
   - touch cabal.project
   - |
     echo "packages: ." >> cabal.project
+  - if [ $HCNUMVER -ge 80000 ] ; then echo 'package some' >> cabal.project ; fi
+  - "if [ $HCNUMVER -ge 80000 ] ; then echo '  ghc-options: -Werror=missing-methods' >> cabal.project ; fi"
   - |
   - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(some)$' || true) | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
   - cat cabal.project || true
@@ -141,6 +143,8 @@ script:
   - touch cabal.project
   - |
     echo "packages: ${PKGDIR_some}" >> cabal.project
+  - if [ $HCNUMVER -ge 80000 ] ; then echo 'package some' >> cabal.project ; fi
+  - "if [ $HCNUMVER -ge 80000 ] ; then echo '  ghc-options: -Werror=missing-methods' >> cabal.project ; fi"
   - |
   - "for pkg in $($HCPKG list --simple-output); do echo $pkg | sed 's/-[^-]*$//' | (grep -vE -- '^(some)$' || true) | sed 's/^/constraints: /' | sed 's/$/ installed/' >> cabal.project.local; done"
   - cat cabal.project || true
@@ -167,5 +171,5 @@ script:
   # Constraint set unsafe
   - ${CABAL} v2-build $WITHCOMPILER --disable-tests --disable-benchmarks --constraint='some +newtype-unsafe' all
 
-# REGENDATA ("0.9.20200325",["--config=cabal.haskell-ci","cabal.project"])
+# REGENDATA ("0.9.20200326",["--config=cabal.haskell-ci","cabal.project"])
 # EOF

CONTRIBUTING.md

@@ -7,6 +7,7 @@ Patches welcome!
     - Regenerate `.travis.yml` with `haskell-ci regenerate` (get the latest from [GitHub haskell-ci/haskell-ci](https://github.com/haskell-ci/haskell-ci))
 
 - Don't edit `CHANGELOG.md`, rather include a copyable entry in your pull request description. I often process pull requests in bulk, and everyone editing the `CHANGELOG.md` causes unnecessary conflicts.
+- For the same reason, do not edit `version` or `x-revision`
 
 - I use [`stylish-haskell`](https://github.com/jaspervdj/stylish-haskell) to format imports. I encourage you to use it too, when contributing.
 - General code style is 4 spaces, just look around how it looks, it's not so strict.

src/Data/GADT/DeepSeq.hs

@@ -1,8 +1,8 @@
-{-# LANGUAGE CPP #-}
+{-# LANGUAGE CPP         #-}
 #if __GLASGOW_HASKELL__ >= 704
-{-# LANGUAGE Safe         #-}
+{-# LANGUAGE Safe        #-}
 #elif __GLASGOW_HASKELL__ >= 702
-{-# LANGUAGE Trustworthy  #-}
+{-# LANGUAGE Trustworthy #-}
 #endif
 module Data.GADT.DeepSeq (
     GNFData (..),

src/Data/GADT/Show.hs

@@ -1,8 +1,8 @@
 {-# LANGUAGE CPP         #-}
 #if __GLASGOW_HASKELL__ >= 704
-{-# LANGUAGE Safe         #-}
+{-# LANGUAGE Safe        #-}
 #elif __GLASGOW_HASKELL__ >= 702
-{-# LANGUAGE Trustworthy  #-}
+{-# LANGUAGE Trustworthy #-}
 #endif
 module Data.GADT.Show (
     -- * Showing