seereason · Bodigrim · Dec 22, 2025 · Dec 22, 2025
diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
@@ -6,11 +6,11 @@
 #
 #   haskell-ci regenerate
 #
-# For more information, see https://github.com/andreasabel/haskell-ci
+# For more information, see https://github.com/haskell-CI/haskell-ci
 #
-# version: 0.19.20241021
+# version: 0.19.20251211
 #
-# REGENDATA ("0.19.20241021",["github","Diff.cabal"])
+# REGENDATA ("0.19.20251211",["github","Diff.cabal"])
 #
 name: Haskell-CI
 on:
@@ -20,10 +20,13 @@ on:
   pull_request:
     branches:
       - master
+  merge_group:
+    branches:
+      - master
 jobs:
   linux:
     name: Haskell-CI - Linux - ${{ matrix.compiler }}
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     timeout-minutes:
       60
     container:
@@ -32,24 +35,29 @@ jobs:
     strategy:
       matrix:
         include:
-          - compiler: ghc-9.12.20241014
+          - compiler: ghc-9.14.0.20251128
+            compilerKind: ghc
+            compilerVersion: 9.14.0.20251128
+            setup-method: ghcup-prerelease
+            allow-failure: false
+          - compiler: ghc-9.12.2
             compilerKind: ghc
-            compilerVersion: 9.12.20241014
+            compilerVersion: 9.12.2
             setup-method: ghcup
             allow-failure: false
-          - compiler: ghc-9.10.1
+          - compiler: ghc-9.10.3
             compilerKind: ghc
-            compilerVersion: 9.10.1
+            compilerVersion: 9.10.3
             setup-method: ghcup
             allow-failure: false
-          - compiler: ghc-9.8.2
+          - compiler: ghc-9.8.4
             compilerKind: ghc
-            compilerVersion: 9.8.2
+            compilerVersion: 9.8.4
             setup-method: ghcup
             allow-failure: false
-          - compiler: ghc-9.6.6
+          - compiler: ghc-9.6.7
             compilerKind: ghc
-            compilerVersion: 9.6.6
+            compilerVersion: 9.6.7
             setup-method: ghcup
             allow-failure: false
           - compiler: ghc-9.4.8
@@ -89,41 +97,60 @@ jobs:
             allow-failure: false
       fail-fast: false
     steps:
-      - name: apt
+      - name: apt-get install
         run: |
           apt-get update
           apt-get install -y --no-install-recommends gnupg ca-certificates dirmngr curl git software-properties-common libtinfo5 libnuma-dev
+      - name: Install GHCup
+        run: |
           mkdir -p "$HOME/.ghcup/bin"
-          curl -sL https://downloads.haskell.org/ghcup/0.1.30.0/x86_64-linux-ghcup-0.1.30.0 > "$HOME/.ghcup/bin/ghcup"
+          curl -sL https://downloads.haskell.org/ghcup/0.1.50.1/x86_64-linux-ghcup-0.1.50.1 > "$HOME/.ghcup/bin/ghcup"
           chmod a+x "$HOME/.ghcup/bin/ghcup"
-          "$HOME/.ghcup/bin/ghcup" config add-release-channel https://raw.githubusercontent.com/haskell/ghcup-metadata/master/ghcup-prereleases-0.0.8.yaml;
+      - name: Install cabal-install
+        run: |
+          "$HOME/.ghcup/bin/ghcup" install cabal 3.16.0.0 || (cat "$HOME"/.ghcup/logs/*.* && false)
+          echo "CABAL=$HOME/.ghcup/bin/cabal-3.16.0.0 -vnormal+nowrap" >> "$GITHUB_ENV"
+      - name: Install GHC (GHCup)
+        if: matrix.setup-method == 'ghcup'
+        run: |
           "$HOME/.ghcup/bin/ghcup" install ghc "$HCVER" || (cat "$HOME"/.ghcup/logs/*.* && false)
-          "$HOME/.ghcup/bin/ghcup" install cabal 3.12.1.0 || (cat "$HOME"/.ghcup/logs/*.* && false)
+          HC=$("$HOME/.ghcup/bin/ghcup" whereis ghc "$HCVER")
+          HCPKG=$(echo "$HC" | sed 's#ghc$#ghc-pkg#')
+          HADDOCK=$(echo "$HC" | sed 's#ghc$#haddock#')
+          echo "HC=$HC" >> "$GITHUB_ENV"
+          echo "HCPKG=$HCPKG" >> "$GITHUB_ENV"
+          echo "HADDOCK=$HADDOCK" >> "$GITHUB_ENV"
         env:
           HCKIND: ${{ matrix.compilerKind }}
           HCNAME: ${{ matrix.compiler }}
           HCVER: ${{ matrix.compilerVersion }}
-      - name: Set PATH and environment variables
+      - name: Install GHC (GHCup prerelease)
+        if: matrix.setup-method == 'ghcup-prerelease'
         run: |
-          echo "$HOME/.cabal/bin" >> $GITHUB_PATH
-          echo "LANG=C.UTF-8" >> "$GITHUB_ENV"
-          echo "CABAL_DIR=$HOME/.cabal" >> "$GITHUB_ENV"
-          echo "CABAL_CONFIG=$HOME/.cabal/config" >> "$GITHUB_ENV"
-          HCDIR=/opt/$HCKIND/$HCVER
+          "$HOME/.ghcup/bin/ghcup" config add-release-channel prereleases
+          "$HOME/.ghcup/bin/ghcup" install ghc "$HCVER" || (cat "$HOME"/.ghcup/logs/*.* && false)
           HC=$("$HOME/.ghcup/bin/ghcup" whereis ghc "$HCVER")
           HCPKG=$(echo "$HC" | sed 's#ghc$#ghc-pkg#')
           HADDOCK=$(echo "$HC" | sed 's#ghc$#haddock#')
           echo "HC=$HC" >> "$GITHUB_ENV"
           echo "HCPKG=$HCPKG" >> "$GITHUB_ENV"
           echo "HADDOCK=$HADDOCK" >> "$GITHUB_ENV"
-          echo "CABAL=$HOME/.ghcup/bin/cabal-3.12.1.0 -vnormal+nowrap" >> "$GITHUB_ENV"
+        env:
+          HCKIND: ${{ matrix.compilerKind }}
+          HCNAME: ${{ matrix.compiler }}
+          HCVER: ${{ matrix.compilerVersion }}
+      - name: Set PATH and environment variables
+        run: |
+          echo "$HOME/.cabal/bin" >> $GITHUB_PATH
+          echo "LANG=C.UTF-8" >> "$GITHUB_ENV"
+          echo "CABAL_DIR=$HOME/.cabal" >> "$GITHUB_ENV"
+          echo "CABAL_CONFIG=$HOME/.cabal/config" >> "$GITHUB_ENV"
           HCNUMVER=$(${HC} --numeric-version|perl -ne '/^(\d+)\.(\d+)\.(\d+)(\.(\d+))?$/; print(10000 * $1 + 100 * $2 + ($3 == 0 ? $5 != 1 : $3))')
           echo "HCNUMVER=$HCNUMVER" >> "$GITHUB_ENV"
           echo "ARG_TESTS=--enable-tests" >> "$GITHUB_ENV"
           echo "ARG_BENCH=--enable-benchmarks" >> "$GITHUB_ENV"
-          if [ $((HCNUMVER >= 91200)) -ne 0 ] ; then echo "HEADHACKAGE=true" >> "$GITHUB_ENV" ; else echo "HEADHACKAGE=false" >> "$GITHUB_ENV" ; fi
+          if [ $((HCNUMVER >= 91400)) -ne 0 ] ; then echo "HEADHACKAGE=true" >> "$GITHUB_ENV" ; else echo "HEADHACKAGE=false" >> "$GITHUB_ENV" ; fi
           echo "ARG_COMPILER=--$HCKIND --with-compiler=$HC" >> "$GITHUB_ENV"
-          echo "GHCJSARITH=0" >> "$GITHUB_ENV"
         env:
           HCKIND: ${{ matrix.compilerKind }}
           HCNAME: ${{ matrix.compiler }}
@@ -185,7 +212,7 @@ jobs:
           chmod a+x $HOME/.cabal/bin/cabal-plan
           cabal-plan --version
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
         with:
           path: source
       - name: initial cabal.project for sdist
@@ -210,7 +237,11 @@ jobs:
           touch cabal.project.local
           echo "packages: ${PKGDIR_Diff}" >> cabal.project
           echo "package Diff" >> cabal.project
-          echo "    ghc-options: -Werror=missing-methods" >> cabal.project
+          echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project
+          if [ $((HCNUMVER >= 90400)) -ne 0 ] ; then echo "package Diff" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 90400)) -ne 0 ] ; then echo "    ghc-options: -Werror=unused-packages" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 90000)) -ne 0 ] ; then echo "package Diff" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 90000)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
           cat >> cabal.project <<EOF
           EOF
           if $HEADHACKAGE; then
@@ -254,8 +285,8 @@ jobs:
           rm -f cabal.project.local
           $CABAL v2-build $ARG_COMPILER --disable-tests --disable-benchmarks all
       - name: save cache
-        uses: actions/cache/save@v4
         if: always()
+        uses: actions/cache/save@v4
         with:
           key: ${{ runner.os }}-${{ matrix.compiler }}-${{ github.sha }}
           path: ~/.cabal/store
diff --git a/Diff.cabal b/Diff.cabal
@@ -15,10 +15,11 @@ maintainer:          David Fox <dsf@seereason.com>
 Build-Type:          Simple
 
 tested-with:
-  GHC == 9.12.0
-  GHC == 9.10.1
-  GHC == 9.8.2
-  GHC == 9.6.6
+  GHC == 9.14.1
+  GHC == 9.12.2
+  GHC == 9.10.3
+  GHC == 9.8.4
+  GHC == 9.6.7
   GHC == 9.4.8
   GHC == 9.2.8
   GHC == 9.0.2

diff --git a/src/Data/Algorithm/Diff.hs b/src/Data/Algorithm/Diff.hs
@@ -14,6 +14,8 @@
 -- it has \( O(ND) \) time and \( O(D^2) \) space complexity.
 -----------------------------------------------------------------------------
 
+{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
+
 module Data.Algorithm.Diff
     ( Diff, PolyDiff(..)
     -- * Comparing lists for differences