philderbeast · Nov 10, 2026 · Sep 22, 2026 · Sep 22, 2026 · Sep 22, 2026 · Sep 22, 2026
diff --git a/cabal-install/src/Distribution/Client/Init/NonInteractive/Command.hs b/cabal-install/src/Distribution/Client/Init/NonInteractive/Command.hs
@@ -41,7 +41,6 @@ import Distribution.Client.Init.Types
 import Distribution.Client.Compat.Prelude hiding (getLine, head, last, putStr, putStrLn)
 import Prelude ()
 
-import Data.List (last)
 import qualified Data.List.NonEmpty as NEL
 
 import Distribution.CabalSpecVersion (CabalSpecVersion (..))
@@ -56,15 +55,15 @@ import Distribution.Simple.Setup (fromFlagOrDefault, pattern Flag, pattern NoFla
 import Distribution.Solver.Types.PackageIndex (elemByPackageName)
 import Distribution.Types.Dependency (Dependency (..))
 import Distribution.Types.PackageName (PackageName, unPackageName)
-import Distribution.Utils.Generic (safeHead)
+import Distribution.Utils.Generic (safeHead, safeLast)
 import Distribution.Verbosity
 import Distribution.Version (Version)
 
 import Language.Haskell.Extension (Extension (..), Language (..))
 
 import qualified Data.Set as Set
 import Distribution.FieldGrammar.Newtypes
-import System.FilePath (splitDirectories, (</>))
+import System.FilePath ((</>))
 
 -- | Main driver for interactive prompt code.
 createProject
@@ -267,7 +266,7 @@ packageNameHeuristics sourcePkgDb flags = getPackageName flags $ do
   defName <-
     guessPackageName =<< case packageDir flags of
       Flag a -> return a
-      NoFlag -> last . splitDirectories <$> getCurrentDirectory
+      NoFlag -> getCurrentDirectory
 
   when (isPkgRegistered defName) $
     putStrLn (inUseMsg defName)
@@ -413,7 +412,7 @@ libOtherModulesHeuristics flags = case otherModules flags of
     if exists
       then do
         otherModules' <- filter isHaskell <$> listFilesRecursive libDir
-        filter ((`elem` otherCandidates) . last . components)
+        filter (maybe False (`elem` otherCandidates) . safeLast . components)
           . catMaybes
           <$> traverse retrieveModuleName otherModules'
       else return []

diff --git a/cabal-install/src/Distribution/Client/Init/NonInteractive/Heuristics.hs b/cabal-install/src/Distribution/Client/Init/NonInteractive/Heuristics.hs
@@ -32,15 +32,14 @@ import Distribution.Client.Compat.Prelude hiding (many, readFile, (<|>))
 import Distribution.Simple.Setup (fromFlagOrDefault)
 
 import Data.Functor ((<&>))
-import qualified Data.List as L
 import qualified Data.Set as Set
 import Distribution.CabalSpecVersion
 import Distribution.Client.Init.Defaults
 import Distribution.Client.Init.FlagExtractors (getCabalVersionNoPrompt)
 import Distribution.Client.Init.Types
 import Distribution.Client.Init.Utils
 import Distribution.FieldGrammar.Newtypes
-import Distribution.Simple.Utils (ordNub)
+import Distribution.Simple.Utils (ordNub, safeLast)
 import Distribution.Types.PackageName (PackageName)
 import Distribution.Version
 import System.FilePath
@@ -101,7 +100,7 @@ guessPackageType flags = do
   if fromFlagOrDefault False (initializeTestSuite flags)
     then return TestSuite
     else do
-      let lastDir dirs = L.last . splitDirectories $ dirs
+      let lastDir dirs = fromMaybe "" . safeLast . splitDirectories $ dirs
           srcCandidates = [defaultSourceDir, "src", "source"]
           testCandidates = [defaultTestDir, "test", "tests"]
 

diff --git a/cabal-install/src/Distribution/Client/ProjectConfig/Types.hs b/cabal-install/src/Distribution/Client/ProjectConfig/Types.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE DerivingVia #-}
+{-# LANGUAGE NamedFieldPuns #-}
 
 -- | Handling project configuration, types.
 module Distribution.Client.ProjectConfig.Types
@@ -501,4 +502,53 @@ data BuildTimeSettings = BuildTimeSettings
   }
   deriving (Generic)
 
-instance NFData BuildTimeSettings
+-- | This instance avoids the deepseq deprecation of @NFData (a -> b)@ triggered
+-- by buildSettingLogFile the alternative @instance NFData BuildTimeSettings@.
+instance NFData BuildTimeSettings where
+  rnf
+    BuildTimeSettings
+      { buildSettingDryRun
+      , buildSettingOnlyDeps
+      , buildSettingOnlyDownload
+      , buildSettingSummaryFile
+      , buildSettingLogFile
+      , buildSettingLogVerbosity
+      , buildSettingBuildReports
+      , buildSettingReportPlanningFailure
+      , buildSettingSymlinkBinDir
+      , buildSettingNumJobs
+      , buildSettingKeepGoing
+      , buildSettingOfflineMode
+      , buildSettingKeepTempFiles
+      , buildSettingRemoteRepos
+      , buildSettingLocalNoIndexRepos
+      , buildSettingCacheDir
+      , buildSettingHttpTransport
+      , buildSettingIgnoreExpiry
+      , buildSettingProgPathExtra
+      , buildSettingHaddockOpen
+      , buildSettingBuildTimings
+      } =
+      rnf
+        [ rnf buildSettingDryRun
+        , rnf buildSettingOnlyDeps
+        , rnf buildSettingOnlyDownload
+        , rnf buildSettingSummaryFile
+        , maybe () (`seq` ()) buildSettingLogFile
+        , rnf buildSettingLogVerbosity
+        , rnf buildSettingBuildReports
+        , rnf buildSettingReportPlanningFailure
+        , rnf buildSettingSymlinkBinDir
+        , rnf buildSettingNumJobs
+        , rnf buildSettingKeepGoing
+        , rnf buildSettingOfflineMode
+        , rnf buildSettingKeepTempFiles
+        , rnf buildSettingRemoteRepos
+        , rnf buildSettingLocalNoIndexRepos
+        , rnf buildSettingCacheDir
+        , rnf buildSettingHttpTransport
+        , rnf buildSettingIgnoreExpiry
+        , rnf buildSettingProgPathExtra
+        , rnf buildSettingHaddockOpen
+        , rnf buildSettingBuildTimings
+        ]
diff --git a/cabal-install/tests/IntegrationTests2.hs b/cabal-install/tests/IntegrationTests2.hs
@@ -818,12 +818,12 @@ testTargetProblemsCommon config0 = do
 
           ( \_ ->
               TargetComponentNotProjectLocal
-                (pkgIdMap Map.! "filepath")
-                (CTestName "filepath-tests")
+                (pkgIdMap Map.! "bytestring")
+                (CTestName "bytestring-tests")
                 WholeComponent
           , mkTargetComponent
-              (pkgIdMap Map.! "filepath")
-              (CTestName "filepath-tests")
+              (pkgIdMap Map.! "bytestring")
+              (CTestName "bytestring-tests")
           )
         , -- Components can be explicitly @buildable: False@
 
@@ -877,8 +877,12 @@ testTargetProblemsCommon config0 = do
         , projectConfigShared =
             (projectConfigShared config0)
               { projectConfigConstraints =
+                  -- Constrain bytestring to a source instance, not the
+                  -- installed one, so that its test suite is in the plan.  Any
+                  -- package with a test suite would do but the bytestring
+                  -- package has wide upper bounds.
                   [
-                    ( UserConstraint (UserAnyQualifier "filepath") PackagePropertySource
+                    ( UserConstraint (UserAnyQualifier "bytestring") PackagePropertySource
                     , ConstraintSourceUnknown
                     )
                   ]

diff --git a/cabal-install/tests/IntegrationTests2/targets/complex/q/q.cabal b/cabal-install/tests/IntegrationTests2/targets/complex/q/q.cabal
@@ -5,8 +5,8 @@ cabal-version: >= 1.2
 
 library
   exposed-modules: Q
-  -- we rely that filepath has filepath-tests component
-  build-depends: base, filepath >=1.4.0.0
+  -- we rely that bytestring has bytestring-tests component
+  build-depends: base, bytestring
 
 executable buildable-false
   main-is: Main.hs

diff --git a/project-cabal/ghc-latest.config b/project-cabal/ghc-latest.config
@@ -8,11 +8,60 @@
 
 -- NOTE: don't forget to update the compiler version in the conditional
 -- when upgrading to a newer GHC
-if impl(ghc >= 9.14.0)
+if impl(ghc >= 10)
     allow-newer:
-    --windns:*, rere:*, tree-diff:*, uuid-types:*, these:*, assoc:*, semialign:*, indexed-traversable-instances:*, indexed-traversable:*, OneTuple:*, scientific:*, time-compat:*, text-short:*, integer-conversion:*, generically:*, data-fix:*, binary:*
-    -- Artem, 2024-04-21: I started and then gave up...
-        *:base, *:template-haskell, text-short, *:deepseq, *:bytestring, *:ghc-prim, *:ghc-bignum, *:containers
+        aeson:template-haskell
+      , aeson:time
+      , assoc:base
+      , async:base
+      , bifunctors:template-haskell
+      , data-fix:base
+      , hackage-security:base
+      , hackage-security:ghc-prim
+      , hackage-security:template-haskell
+      , hackage-security:time
+      , hashable:base
+      , hashable:containers
+      , hashable:ghc-bignum
+      , hsc2hs:base
+      , HTTP:base
+      , HTTP:time
+      , indexed-traversable:base
+      , indexed-traversable-instances:base
+      , integer-conversion:base
+      , integer-logarithms:base
+      , nothunks:containers
+      , nothunks:time
+      , OneTuple:base
+      , parallel:base
+      , primitive:base
+      , scientific:base
+      , scientific:template-haskell
+      , semialign:base
+      , splitmix:base
+      , tagged:template-haskell
+      , tasty-bench:ghc-prim
+      , text-iso8601:time
+      , text-short:base
+      , text-short:ghc-prim
+      , text-short:template-haskell
+      , th-abstraction:template-haskell
+      , th-compat:template-haskell
+      , these:base
+      , time-compat:base
+      , time-compat:time
+      , tree-diff:base
+      , unordered-containers:template-haskell
+      , uuid-types:template-haskell
+      , vector:base
+      , vector-stream:base
+      , vector-stream:ghc-prim
+      , vector-th-unbox:base
+      , vector-th-unbox:template-haskell
+      , zinza:base
+      , zlib:base
+    -- Earlier versions of hashable have the ghc-bignum dependency.
+    constraints: hashable < 1.5.1.0
 
 --    repository head.hackage.ghc.haskell.org
 --        url: https://ghc.gitlab.haskell.org/head.hackage/