haskell · meooow25 · Jan 4, 2026 · Jan 3, 2026
diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
@@ -8,9 +8,9 @@
 #
 # For more information, see https://github.com/haskell-CI/haskell-ci
 #
-# version: 0.19.20250216
+# version: 0.19.20260102
 #
-# REGENDATA ("0.19.20250216",["github","--config=cabal.haskell-ci","--ghc-head","cabal.project"])
+# REGENDATA ("0.19.20260102",["github","--config=cabal.haskell-ci","--ghc-head","cabal.project"])
 #
 name: Haskell-CI
 on:
@@ -20,6 +20,9 @@ on:
   pull_request:
     branches:
       - master
+  merge_group:
+    branches:
+      - master
 jobs:
   linux:
     name: Haskell-CI - Linux - ${{ matrix.compiler }}
@@ -32,14 +35,19 @@ jobs:
     strategy:
       matrix:
         include:
-          - compiler: ghc-9.12.1
+          - compiler: ghc-9.14.1
+            compilerKind: ghc
+            compilerVersion: 9.14.1
+            setup-method: ghcup
+            allow-failure: false
+          - compiler: ghc-9.12.2
             compilerKind: ghc
-            compilerVersion: 9.12.1
+            compilerVersion: 9.12.2
             setup-method: ghcup
             allow-failure: false
-          - compiler: ghc-9.10.1
+          - compiler: ghc-9.10.3
             compilerKind: ghc
-            compilerVersion: 9.10.1
+            compilerVersion: 9.10.3
             setup-method: ghcup
             allow-failure: false
           - compiler: ghc-9.8.4
@@ -101,12 +109,12 @@ jobs:
       - name: Install GHCup
         run: |
           mkdir -p "$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 "$HOME/.ghcup/bin/ghcup"
       - name: Install cabal-install
         run: |
-          "$HOME/.ghcup/bin/ghcup" install cabal 3.12.1.0 || (cat "$HOME"/.ghcup/logs/*.* && false)
-          echo "CABAL=$HOME/.ghcup/bin/cabal-3.12.1.0 -vnormal+nowrap" >> "$GITHUB_ENV"
+          "$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" >> "$GITHUB_ENV"
       - name: Install GHC (GHCup)
         if: matrix.setup-method == 'ghcup'
         run: |
@@ -131,7 +139,7 @@ jobs:
           echo "HCNUMVER=$HCNUMVER" >> "$GITHUB_ENV"
           echo "ARG_TESTS=--enable-tests" >> "$GITHUB_ENV"
           echo "ARG_BENCH=--enable-benchmarks" >> "$GITHUB_ENV"
-          if [ $((HCNUMVER > 91201)) -ne 0 ] ; then echo "HEADHACKAGE=true" >> "$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"
         env:
           HCKIND: ${{ matrix.compilerKind }}
@@ -194,7 +202,7 @@ 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
@@ -223,9 +231,13 @@ jobs:
           echo "packages: ${PKGDIR_containers}" >> cabal.project
           echo "packages: ${PKGDIR_containers_tests}" >> cabal.project
           echo "package containers" >> cabal.project
-          echo "    ghc-options: -Werror=missing-methods" >> cabal.project
+          echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project
           echo "package containers-tests" >> cabal.project
-          echo "    ghc-options: -Werror=missing-methods" >> cabal.project
+          echo "    ghc-options: -Werror=missing-methods -Werror=missing-fields" >> cabal.project
+          if [ $((HCNUMVER >= 90000)) -ne 0 ] ; then echo "package containers" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 90000)) -ne 0 ] ; then echo "    ghc-options: -Werror=incomplete-patterns -Werror=incomplete-uni-patterns" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 90000)) -ne 0 ] ; then echo "package containers-tests" >> 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
           allow-newer: all:containers
           EOF

diff --git a/cabal.haskell-ci b/cabal.haskell-ci
@@ -12,3 +12,7 @@ install-dependencies: False
 installed: +all -binary -text
 
 cabal-check: False
+
+-- Stop haskell-ci from inserting -Werror=unused-packages
+-- https://github.com/haskell-CI/haskell-ci/pull/789#issuecomment-3224566698
+error-unused-packages: False
diff --git a/containers-tests/benchmarks/IntMap.hs b/containers-tests/benchmarks/IntMap.hs
@@ -191,6 +191,7 @@ maybeDel n | n `mod` 3 == 0 = Nothing
 ------------------------------------------------------------
 interleave :: [Int] -> [Int] -> [Int]
 interleave [] ys = ys
+interleave xs [] = xs
 interleave (x:xs) (y:ys) = x : y : interleave xs ys
 
 unitValues :: [Int] -> [(Int, ())]

diff --git a/containers-tests/benchmarks/IntSet.hs b/containers-tests/benchmarks/IntSet.hs
@@ -139,6 +139,7 @@ fromListNoinline = IS.fromList
 
 interleave :: [a] -> [a] -> [a]
 interleave [] ys = ys
+interleave xs [] = xs
 interleave (x:xs) (y:ys) = x : y : interleave xs ys
 
 gen :: StdGen

diff --git a/containers-tests/benchmarks/Sequence.hs b/containers-tests/benchmarks/Sequence.hs
@@ -226,8 +226,7 @@ fakeDeleteAt i xs
 -- and rejoin the pieces in the opposite order.
 -- Finally getting the middle element forces the whole spine.
 shuffle :: [Int] -> S.Seq Int -> Int
-shuffle ps s = case S.viewl (S.drop (S.length s `div` 2) (foldl' cut s ps)) of
-    x S.:< _ -> x
+shuffle ps s = S.index (foldl' cut s ps) (S.length s `div` 2)
   where cut xs p = let (front, back) = S.splitAt p xs in back S.>< front
 
 stateReplicate :: Int -> S.Seq Char

diff --git a/containers-tests/containers-tests.cabal b/containers-tests/containers-tests.cabal
@@ -27,7 +27,7 @@ extra-source-files:
 
 tested-with:
   GHC ==8.2.2 || ==8.4.4 || ==8.6.5 || ==8.8.4 || ==8.10.7 || ==9.0.2 || ==9.2.8 ||
-      ==9.4.8 || ==9.6.6 || ==9.8.4 || ==9.10.1 || ==9.12.1
+      ==9.4.8 || ==9.6.6 || ==9.8.4 || ==9.10.3 || ==9.12.2 || ==9.14.1
 
 source-repository head
   type:     git
@@ -37,11 +37,14 @@ common deps
   build-depends:
       array    >=0.4.0.0
     , base     >=4.10    && <5
-    , deepseq  >=1.2     && <1.6
+    , deepseq >= 1.4.3.0 && < 1.6
     , template-haskell
 
 common warnings
-  ghc-options: -Werror=unused-top-binds
+  ghc-options:
+    -Werror=unused-top-binds
+    -Werror=incomplete-patterns
+    -Werror=incomplete-uni-patterns
 
 common test-deps
   import: deps
@@ -58,7 +61,6 @@ common benchmark-deps
   import: deps
   build-depends:
       containers-tests
-    , deepseq           >=1.1.0.0 && <1.6
     , OneTuple
     , tasty-bench       >=0.3.1   && <0.5
 
@@ -295,7 +297,6 @@ benchmark lookupge-intmap
   hs-source-dirs: benchmarks/LookupGE
   main-is:        IntMap.hs
   other-modules:  LookupGE_IntMap
-  build-depends:  containers-tests
 
 benchmark lookupge-map
   import: benchmark-deps, warnings
@@ -304,7 +305,6 @@ benchmark lookupge-map
   hs-source-dirs: benchmarks/LookupGE
   main-is:        Map.hs
   other-modules:  LookupGE_Map
-  build-depends:  containers-tests
   ghc-options:    -O2
 
 -------------------

diff --git a/containers-tests/tests/intmap-properties.hs b/containers-tests/tests/intmap-properties.hs
@@ -1386,6 +1386,7 @@ prop_mergeWithKeyModel xs ys
                                             (Nothing, Just y) -> if keep_y then Just (k, y) else Nothing
                                             (Just x, Nothing) -> if keep_x then Just (k, x) else Nothing
                                             (Just x, Just y) -> (\v -> (k, v)) `fmap` f k x y
+                                            (Nothing, Nothing) -> error "impossible"
 
           -- We prevent inlining testMergeWithKey to disable the SpecConstr
           -- optimalization. There are too many call patterns here so several
@@ -1951,14 +1952,18 @@ prop_maxViewWithKey m = case maxViewWithKey m of
 prop_minView :: IntMap A -> Property
 prop_minView m = case minView m of
   Nothing -> property $ null m
-  Just (x,m') | ~(_,x'):xs' <- toList m ->
-    valid m' .&&. x == x' .&&. toList m' === xs'
+  Just (x,m') -> valid m' .&&. kxs === (minKey, x) : toList m'
+    where
+      kxs = toList m
+      minKey = minimum (fmap fst kxs)
 
 prop_maxView :: IntMap A -> Property
 prop_maxView m = case maxView m of
   Nothing -> property $ null m
-  Just (x,m') | ~(_,x'):xs' <- toDescList m ->
-    valid m' .&&. x == x' .&&. toDescList m' === xs'
+  Just (x,m') -> valid m' .&&. kxs === (maxKey, x) : toDescList m'
+    where
+      kxs = toDescList m
+      maxKey = maximum (fmap fst kxs)
 
 prop_mapEither :: Fun A (Either B C) -> IntMap A -> Property
 prop_mapEither f m =

diff --git a/containers-tests/tests/map-properties.hs b/containers-tests/tests/map-properties.hs
@@ -1242,6 +1242,7 @@ prop_mergeWithKeyModel xs ys
                                             (Nothing, Just y) -> if keep_y then Just (k, y) else Nothing
                                             (Just x, Nothing) -> if keep_x then Just (k, x) else Nothing
                                             (Just x, Just y) -> (\v -> (k, v)) `fmap` f k x y
+                                            (Nothing, Nothing) -> error "impossible"
 
           -- We prevent inlining testMergeWithKey to disable the SpecConstr
           -- optimalization. There are too many call patterns here so several
@@ -1914,14 +1915,18 @@ prop_maxViewWithKey m = case maxViewWithKey m of
 prop_minView :: Map Int A -> Property
 prop_minView m = case minView m of
   Nothing -> property $ null m
-  Just (x,m') | ~(_,x'):xs' <- toList m ->
-    valid m' .&&. x == x' .&&. toList m' === xs'
+  Just (x,m') -> valid m' .&&. kxs === (minKey, x) : toList m'
+    where
+      kxs = toList m
+      minKey = minimum (fmap fst kxs)
 
 prop_maxView :: Map Int A -> Property
 prop_maxView m = case maxView m of
   Nothing -> property $ null m
-  Just (x,m') | ~(_,x'):xs' <- toDescList m ->
-    valid m' .&&. x == x' .&&. toDescList m' === xs'
+  Just (x,m') -> valid m' .&&. kxs === (maxKey, x) : toDescList m'
+    where
+      kxs = toDescList m
+      maxKey = maximum (fmap fst kxs)
 
 prop_isSubmapOf :: Map Int A -> Map Int A -> Property
 prop_isSubmapOf m1 m2 = isSubmapOf m1 m2 === all (`elem` kys) (toList m1)

diff --git a/containers/containers.cabal b/containers/containers.cabal
@@ -30,7 +30,7 @@ extra-source-files:
 
 tested-with:
   GHC ==8.2.2 || ==8.4.4 || ==8.6.5 || ==8.8.4 || ==8.10.7 || ==9.0.2 || ==9.2.8 ||
-      ==9.4.8 || ==9.6.6 || ==9.8.4 || ==9.10.1 || ==9.12.1
+      ==9.4.8 || ==9.6.6 || ==9.8.4 || ==9.10.3 || ==9.12.2 || ==9.14.1
 
 source-repository head
     type:     git