upgrade to ghc 9.10

.github/workflows/ci.yml

@@ -13,31 +13,18 @@ jobs:
   build:
     strategy:
       matrix:
-        ghc: ['9.0.2', '9.2.7', '9.4.4', '9.6.1']
-        cabal: ['3.4.1.0', '3.6.2.0', '3.8.1.0', '3.10.1.0']
-        os: ['ubuntu-latest', 'macos-latest']
-        exclude:
-          # Cabal 3.4.1.0 supports GHC version < 9.1
-          - cabal: '3.4.1.0'
-            ghc: '9.2.7'
-          - cabal: '3.4.1.0'
-            ghc: '9.4.4'
-          - cabal: '3.4.1.0'
-            ghc: '9.6.1'
-          # Cabal 3.6.2.0 supports GHC version < 9.4
-          - cabal: '3.6.2.0'
-            ghc: '9.4.4'
-          - cabal: '3.6.2.0'
-            ghc: '9.6.1'
+        ghc: ['9.0.2', '9.2.8', '9.4.8', '9.6.7', '9.8.4', '9.10.3']
+        cabal: ['3.10.2.0', '3.12.1.0', '3.14.2.0', '3.16.1.0']
+        os: ['ubuntu-latest']
     runs-on: ${{ matrix.os }}
     name: platform ${{ matrix.os }} GHC ${{ matrix.ghc }} cabal ${{ matrix.cabal }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v6
 
       - name: Setup Haskell
         id: setup-haskell
-        uses: haskell/actions/setup@v2
+        uses: haskell-actions/setup@v2
         with:
           ghc-version: ${{ matrix.ghc }}
           cabal-version: ${{ matrix.cabal }}
@@ -49,9 +36,6 @@ jobs:
           key: ${{ runner.os }}-${{ matrix.ghc }}-${{ github.sha }}
           restore-keys: ${{ runner.os }}-${{ matrix.ghc }}-
 
-      - name: Update cabal package list
-        run: cabal update
-
       - name: Build dependencies
         run: cabal build --only-dependencies
 
@@ -65,7 +49,6 @@ jobs:
         run: cabal test --index-state HEAD
 
       - name: Test on oldest dependencies
-        if: matrix.cabal == '3.10.1.0'
         run: cabal test --prefer-oldest
 
   format:
@@ -75,4 +58,6 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Check code formatting
-        uses: fourmolu/fourmolu-action@v6
+        uses: haskell-actions/run-fourmolu@v12
+        with:
+          version: "0.19.0.1"

cabal.project

@@ -1,4 +1,4 @@
-index-state: 2023-03-14T09:58:19Z
+index-state: 2026-04-09T08:51:20Z
 packages: *.cabal
 write-ghc-environment-files: always
 tests: True

crem.cabal

@@ -1,6 +1,6 @@
 cabal-version: 2.0
 
--- This file has been generated from package.yaml by hpack version 0.35.2.
+-- This file has been generated from package.yaml by hpack version 0.38.3.
 --
 -- see: https://github.com/sol/hpack
 
@@ -19,21 +19,18 @@ license-file:   LICENSE
 build-type:     Simple
 tested-with:
     GHC ==9.0.2
-  , GHC ==9.2.7
-  , GHC ==9.4.4
-  , GHC ==9.6.1
+  , GHC ==9.2.8
+  , GHC ==9.4.8
+  , GHC ==9.6.7
+  , GHC ==9.8.4
+  , GHC ==9.10.3
 extra-source-files:
     README.md
     CHANGELOG.md
 
 flag errors
   description: enable -Werror
   manual: True
-  default: False
-
-flag test-doctest
-  description: run doctests
-  manual: True
   default: True
 
 library
@@ -52,14 +49,15 @@ library
       DerivingStrategies
       LambdaCase
       PackageImports
+      RoleAnnotations
   ghc-options: -Weverything -Wno-safe -Wno-unsafe -Wno-missing-safe-haskell-mode -Wno-implicit-prelude -Wno-missing-export-lists -Wno-missing-home-modules -Wno-missing-import-lists -Wno-all-missed-specialisations -Wno-prepositive-qualified-module
   build-depends:
-      base >=4.15 && <4.19
+      base >=4.15 && <4.21
     , machines >=0.7.3 && <0.8
     , nothunks >=0.1 && <0.4
     , profunctors >=3.2 && <5.7
-    , singletons-base >=3.0 && <3.3
-    , text >=1.2 && <2.1
+    , singletons-base >=3.0 && <3.5
+    , text >=1.2 && <2.2
   default-language: Haskell2010
   if impl(ghc >= 9.2)
     ghc-options: -Wno-missing-kind-signatures
@@ -142,9 +140,10 @@ library crem-examples
       DerivingStrategies
       LambdaCase
       PackageImports
+      RoleAnnotations
   ghc-options: -Weverything -Wno-safe -Wno-unsafe -Wno-missing-safe-haskell-mode -Wno-implicit-prelude -Wno-missing-export-lists -Wno-missing-home-modules -Wno-missing-import-lists -Wno-all-missed-specialisations -Wno-prepositive-qualified-module
   build-depends:
-      base >=4.15 && <4.19
+      base >=4.15 && <4.21
     , crem
     , profunctors
     , singletons-base
@@ -211,9 +210,10 @@ executable hobbit-game
       DerivingStrategies
       LambdaCase
       PackageImports
+      RoleAnnotations
   ghc-options: -Weverything -Wno-safe -Wno-unsafe -Wno-missing-safe-haskell-mode -Wno-implicit-prelude -Wno-missing-export-lists -Wno-missing-home-modules -Wno-missing-import-lists -Wno-all-missed-specialisations -Wno-prepositive-qualified-module
   build-depends:
-      base >=4.15 && <4.19
+      base >=4.15 && <4.21
     , crem
     , crem-examples
   default-language: Haskell2010
@@ -278,9 +278,10 @@ executable hobbit-map
       DerivingStrategies
       LambdaCase
       PackageImports
+      RoleAnnotations
   ghc-options: -Weverything -Wno-safe -Wno-unsafe -Wno-missing-safe-haskell-mode -Wno-implicit-prelude -Wno-missing-export-lists -Wno-missing-home-modules -Wno-missing-import-lists -Wno-all-missed-specialisations -Wno-prepositive-qualified-module
   build-depends:
-      base >=4.15 && <4.19
+      base >=4.15 && <4.21
     , crem
     , crem-examples
     , text
@@ -347,12 +348,15 @@ test-suite crem-doctests
       DerivingStrategies
       LambdaCase
       PackageImports
+      RoleAnnotations
   ghc-options: -Weverything -Wno-safe -Wno-unsafe -Wno-missing-safe-haskell-mode -Wno-implicit-prelude -Wno-missing-export-lists -Wno-missing-home-modules -Wno-missing-import-lists -Wno-all-missed-specialisations -Wno-prepositive-qualified-module -threaded -Wno-unused-packages
   build-depends:
-      base >=4.15 && <4.19
+      Cabal
+    , base >=4.15 && <4.21
     , crem
     , crem-examples
-    , doctest-parallel >=0.2.3 && <0.4
+    , doctest-parallel >=0.2.3 && <0.5
+    , ghc
   default-language: Haskell2010
   if impl(ghc >= 9.2)
     ghc-options: -Wno-missing-kind-signatures
@@ -406,10 +410,6 @@ test-suite crem-doctests
         TypeSynonymInstances
   if flag(errors)
     ghc-options: -Werror
-  if flag(test-doctest)
-    buildable: True
-  else
-    buildable: False
 
 test-suite crem-spec
   type: exitcode-stdio-1.0
@@ -427,11 +427,12 @@ test-suite crem-spec
       DerivingStrategies
       LambdaCase
       PackageImports
+      RoleAnnotations
   ghc-options: -Weverything -Wno-safe -Wno-unsafe -Wno-missing-safe-haskell-mode -Wno-implicit-prelude -Wno-missing-export-lists -Wno-missing-home-modules -Wno-missing-import-lists -Wno-all-missed-specialisations -Wno-prepositive-qualified-module
   build-tool-depends:
       hspec-discover:hspec-discover
   build-depends:
-      base >=4.15 && <4.19
+      base >=4.15 && <4.21
     , crem
     , crem-examples
     , hspec >=2.7 && <2.12

decision-log/2026-04-09-renounce-literate-haskell.yaml

@@ -0,0 +1,12 @@
+name: renounce literate Haskell
+date: 2026-04-09
+context: >
+  Currently we are using literate Haskell for one example where the comments take the most part of the file.
+
+  This always created issues with `doctest-parallel` execution, since the library is not able to parse literate Haskell files.
+
+  Moreover, lately we found that, when trying to use CPP conditionals inside a literate Haskell files, then it fails to compile.
+decision: >
+  We decide to renounce literate Haskell, since it is creating more issues that the value it is providing
+consequences: >
+  We `unlit` the literate Haskell file, and we turn it into a normal Haskell module with a lot of comments

decision-log/2026-04-10-remove-macos-from-ci.yaml

@@ -0,0 +1,19 @@
+name: remove macos from ci
+date: 2026-04-10
+context: >
+  With the support for GHC 9.10 and newer cabal versions, we stumbled into an issue with respect to builds with `macos` machines.
+
+  The issue present itself as follows, during `cabal build`:
+
+  ```
+  <no location info>: error:
+      Warning: Couldn't figure out LLVM version!
+               Make sure you have installed LLVM between [9 and 13)
+  ghc-9.0.2: could not execute: opt
+  ```
+
+  I tried applying the suggestions frm https://discourse.haskell.org/t/cabal-and-llvm-issue/3672 but was not able to solve the issue.
+decision: >
+  For the moment the decision is to remove `macos` machines from CI and hide the issue under the carpet.
+consequences: >
+  I will create an issue about this if someone more knowledgeable than me wants to fix this.

examples/Crem/Example/Cart/Aggregate.hs

@@ -1,10 +1,19 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DerivingVia #-}
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE UndecidableInstances #-}
 -- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag--Wmissing-deriving-strategies
 {-# OPTIONS_GHC -Wno-missing-deriving-strategies #-}
+
+#if __GLASGOW_HASKELL__ >= 908
+-- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag-Wmissing-poly-kind-signatures
+{-# OPTIONS_GHC -Wno-missing-poly-kind-signatures #-}
+-- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag-Wmissing-role-annotations
+{-# OPTIONS_GHC -Wno-missing-role-annotations #-}
+#endif
+
 -- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag--Wunticked-promoted-constructors
 {-# OPTIONS_GHC -Wno-unticked-promoted-constructors #-}
 -- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag--Wunused-type-patterns
@@ -20,21 +29,21 @@ import Crem.Topology
 import "singletons-base" Data.Singletons.Base.TH
 
 $( singletons
-    [d|
-      data CartVertex
-        = WaitingForPayment
-        | InitiatingPayment
-        | PaymentComplete
-        deriving stock (Eq, Show, Enum, Bounded)
-
-      cartTopology :: Topology CartVertex
-      cartTopology =
-        Topology
-          [ (WaitingForPayment, [InitiatingPayment])
-          , (InitiatingPayment, [PaymentComplete])
-          , (PaymentComplete, [])
-          ]
-      |]
+     [d|
+       data CartVertex
+         = WaitingForPayment
+         | InitiatingPayment
+         | PaymentComplete
+         deriving stock (Eq, Show, Enum, Bounded)
+
+       cartTopology :: Topology CartVertex
+       cartTopology =
+         Topology
+           [ (WaitingForPayment, [InitiatingPayment])
+           , (InitiatingPayment, [PaymentComplete])
+           , (PaymentComplete, [])
+           ]
+       |]
  )
 
 deriving via AllVertices CartVertex instance RenderableVertices CartVertex

examples/Crem/Example/Cart/Shipping.hs

@@ -1,10 +1,19 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DerivingVia #-}
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE UndecidableInstances #-}
 -- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag--Wmissing-deriving-strategies
 {-# OPTIONS_GHC -Wno-missing-deriving-strategies #-}
+
+#if __GLASGOW_HASKELL__ >= 908
+-- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag-Wmissing-poly-kind-signatures
+{-# OPTIONS_GHC -Wno-missing-poly-kind-signatures #-}
+-- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag-Wmissing-role-annotations
+{-# OPTIONS_GHC -Wno-missing-role-annotations #-}
+#endif
+
 -- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag--Wredundant-constraints
 {-# OPTIONS_GHC -Wno-redundant-constraints #-}
 -- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag--Wunticked-promoted-constructors
@@ -31,13 +40,13 @@ data ShippingCommand
 data ShippingEvent
 
 $( singletons
-    [d|
-      data ShippingVertex = ShippingVertex
-        deriving stock (Eq, Show, Enum, Bounded)
+     [d|
+       data ShippingVertex = ShippingVertex
+         deriving stock (Eq, Show, Enum, Bounded)
 
-      shippingTopology :: Topology ShippingVertex
-      shippingTopology = Topology []
-      |]
+       shippingTopology :: Topology ShippingVertex
+       shippingTopology = Topology []
+       |]
  )
 
 deriving via AllVertices ShippingVertex instance RenderableVertices ShippingVertex

examples/Crem/Example/LockDoor.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DerivingVia #-}
 {-# LANGUAGE TemplateHaskell #-}
@@ -7,6 +8,14 @@
 {-# OPTIONS_GHC -Wno-all-missed-specialisations #-}
 -- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag--Wmissing-deriving-strategies
 {-# OPTIONS_GHC -Wno-missing-deriving-strategies #-}
+
+#if __GLASGOW_HASKELL__ >= 908
+-- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag-Wmissing-poly-kind-signatures
+{-# OPTIONS_GHC -Wno-missing-poly-kind-signatures #-}
+-- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag-Wmissing-role-annotations
+{-# OPTIONS_GHC -Wno-missing-role-annotations #-}
+#endif
+
 -- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag--Wunticked-promoted-constructors
 {-# OPTIONS_GHC -Wno-unticked-promoted-constructors #-}
 -- https://downloads.haskell.org/ghc/latest/docs/users_guide/using-warnings.html#ghc-flag--Wunused-type-patterns
@@ -20,21 +29,21 @@ import Crem.Topology
 import "singletons-base" Data.Singletons.Base.TH
 
 $( singletons
-    [d|
-      data LockDoorVertex
-        = IsLockOpen
-        | IsLockClosed
-        | IsLockLocked
-        deriving stock (Eq, Show, Enum, Bounded)
+     [d|
+       data LockDoorVertex
+         = IsLockOpen
+         | IsLockClosed
+         | IsLockLocked
+         deriving stock (Eq, Show, Enum, Bounded)
 
-      lockDoorTopology :: Topology LockDoorVertex
-      lockDoorTopology =
-        Topology
-          [ (IsLockOpen, [IsLockClosed])
-          , (IsLockClosed, [IsLockOpen, IsLockLocked])
-          , (IsLockLocked, [IsLockClosed])
-          ]
-      |]
+       lockDoorTopology :: Topology LockDoorVertex
+       lockDoorTopology =
+         Topology
+           [ (IsLockOpen, [IsLockClosed])
+           , (IsLockClosed, [IsLockOpen, IsLockLocked])
+           , (IsLockLocked, [IsLockClosed])
+           ]
+       |]
  )
 
 deriving via AllVertices LockDoorVertex instance RenderableVertices LockDoorVertex