diff --git a/Cabal-hooks/Cabal-hooks.cabal b/Cabal-hooks/Cabal-hooks.cabal
index 419f15764b9..367ef185610 100644
--- a/Cabal-hooks/Cabal-hooks.cabal
+++ b/Cabal-hooks/Cabal-hooks.cabal
@@ -31,7 +31,6 @@ library
     Cabal           >= 3.13      && < 3.15,
     base            >= 4.11      && < 5,
     containers      >= 0.5.0.0   && < 0.8,
-    filepath        >= 1.3.0.1   && < 1.5,
     transformers    >= 0.5.6.0   && < 0.7
 
   ghc-options: -Wall -fno-ignore-asserts -fwarn-tabs -fwarn-incomplete-uni-patterns -fwarn-incomplete-record-updates
diff --git a/Cabal-hooks/src/Distribution/Simple/SetupHooks.hs b/Cabal-hooks/src/Distribution/Simple/SetupHooks.hs
index 488387b8e2f..2b49ffc5e5f 100644
--- a/Cabal-hooks/src/Distribution/Simple/SetupHooks.hs
+++ b/Cabal-hooks/src/Distribution/Simple/SetupHooks.hs
@@ -78,8 +78,8 @@ module Distribution.Simple.SetupHooks
     -- *** Rule inputs/outputs
 
     -- $rulesDemand
-  , Location
-  , findFileInDirs
+  , Location(..)
+  , location
   , autogenComponentModulesDir
   , componentBuildDir
 
@@ -202,7 +202,7 @@ import Distribution.Simple.SetupHooks.Errors
 import Distribution.Simple.SetupHooks.Internal
 import Distribution.Simple.SetupHooks.Rule as Rule
 import Distribution.Simple.Utils
-  ( dieWithException, findFirstFile)
+  ( dieWithException )
 import Distribution.System
   ( Platform(..) )
 import Distribution.Types.Component
@@ -235,12 +235,8 @@ import qualified Control.Monad.Trans.Writer.Strict as Writer
 #endif
 import Data.Foldable
   ( for_ )
-import Data.List
-  ( nub )
 import Data.Map.Strict as Map
   ( insertLookupWithKey )
-import System.FilePath
-  ( (</>) )
 
 --------------------------------------------------------------------------------
 -- Haddocks for the SetupHooks API
@@ -466,14 +462,5 @@ addRuleMonitors :: Monad m => [MonitorFilePath] -> RulesT m ()
 addRuleMonitors = RulesT . lift . lift . Writer.tell
 {-# INLINEABLE addRuleMonitors #-}
 
--- | Find a file in the given search directories.
-findFileInDirs :: FilePath -> [FilePath] -> IO (Maybe Location)
-findFileInDirs file dirs =
-  findFirstFile
-    (uncurry (</>))
-      [ (path, file)
-      | path <- nub dirs
-      ]
-
-  -- TODO: add API functions that search and declare the appropriate monitoring
-  -- at the same time.
+-- TODO: add API functions that search and declare the appropriate monitoring
+-- at the same time.
diff --git a/Cabal/src/Distribution/Simple/SetupHooks/Errors.hs b/Cabal/src/Distribution/Simple/SetupHooks/Errors.hs
index 11577f3506b..22b070e5d41 100644
--- a/Cabal/src/Distribution/Simple/SetupHooks/Errors.hs
+++ b/Cabal/src/Distribution/Simple/SetupHooks/Errors.hs
@@ -20,7 +20,6 @@ module Distribution.Simple.SetupHooks.Errors
   , RulesException (..)
   , setupHooksExceptionCode
   , setupHooksExceptionMessage
-  , showLocs
   ) where
 
 import Distribution.PackageDescription
@@ -35,8 +34,6 @@ import Data.List
 import qualified Data.List.NonEmpty as NE
 import qualified Data.Tree as Tree
 
-import System.FilePath (normalise, (</>))
-
 --------------------------------------------------------------------------------
 
 -- | An error involving the @SetupHooks@ module of a package with
@@ -137,7 +134,7 @@ rulesExceptionMessage = \case
   CantFindSourceForRuleDependencies _r deps ->
     unlines $
       ("Pre-build rules: can't find source for rule " ++ what ++ ":")
-        : map (\d -> "  - " <> locPath d) depsL
+        : map (\d -> "  - " <> show d) depsL
     where
       depsL = NE.toList deps
       what
@@ -148,7 +145,7 @@ rulesExceptionMessage = \case
   MissingRuleOutputs _r reslts ->
     unlines $
       ("Pre-build rule did not generate expected result" <> plural <> ":")
-        : map (\res -> "  - " <> locPath res) resultsL
+        : map (\res -> "  - " <> show res) resultsL
     where
       resultsL = NE.toList reslts
       plural
@@ -181,13 +178,7 @@ rulesExceptionMessage = \case
   where
     showRule :: RuleBinary -> String
     showRule (Rule{staticDependencies = deps, results = reslts}) =
-      "Rule: " ++ showDeps deps ++ " --> " ++ showLocs (NE.toList reslts)
-
-locPath :: Location -> String
-locPath (base, fp) = normalise $ base </> fp
-
-showLocs :: [Location] -> String
-showLocs locs = "[" ++ intercalate ", " (map locPath locs) ++ "]"
+      "Rule: " ++ showDeps deps ++ " --> " ++ show (NE.toList reslts)
 
 showDeps :: [Rule.Dependency] -> String
 showDeps deps = "[" ++ intercalate ", " (map showDep deps) ++ "]"
@@ -196,7 +187,7 @@ showDep :: Rule.Dependency -> String
 showDep = \case
   RuleDependency (RuleOutput{outputOfRule = rId, outputIndex = i}) ->
     "(" ++ show rId ++ ")[" ++ show i ++ "]"
-  FileDependency loc -> locPath loc
+  FileDependency loc -> show loc
 
 cannotApplyComponentDiffCode :: CannotApplyComponentDiffReason -> Int
 cannotApplyComponentDiffCode = \case
diff --git a/Cabal/src/Distribution/Simple/SetupHooks/Internal.hs b/Cabal/src/Distribution/Simple/SetupHooks/Internal.hs
index 25e2f39b1ad..29621ed7567 100644
--- a/Cabal/src/Distribution/Simple/SetupHooks/Internal.hs
+++ b/Cabal/src/Distribution/Simple/SetupHooks/Internal.hs
@@ -89,7 +89,6 @@ import Distribution.Compat.Prelude
 import Prelude ()
 
 import Distribution.Compat.Lens ((.~))
-import Distribution.ModuleName
 import Distribution.PackageDescription
 import Distribution.Simple.BuildPaths
 import Distribution.Simple.Compiler (Compiler (..))
@@ -110,7 +109,7 @@ import Distribution.Simple.SetupHooks.Rule
 import qualified Distribution.Simple.SetupHooks.Rule as Rule
 import Distribution.Simple.Utils
 import Distribution.System (Platform (..))
-import Distribution.Utils.Path (getSymbolicPath)
+import Distribution.Utils.Path
 
 import qualified Distribution.Types.BuildInfo.Lens as BI (buildInfo)
 import Distribution.Types.LocalBuildConfig as LBC
@@ -125,7 +124,6 @@ import qualified Data.Map as Map
 import qualified Data.Set as Set
 
 import System.Directory (doesFileExist)
-import System.FilePath (normalise, (<.>), (</>))
 
 --------------------------------------------------------------------------------
 -- SetupHooks
@@ -898,12 +896,12 @@ executeRulesUserOrSystem scope runDepsCmdData runCmdData verbosity lbi tgtInfo a
     -- SetupHooks TODO: maybe requiring all generated modules to appear
     -- in autogen-modules is excessive; we can look through all modules instead.
     autogenModPaths =
-      map (\m -> toFilePath m <.> "hs") $
+      map (\m -> moduleNameSymbolicPath m <.> "hs") $
         autogenModules $
           componentBuildInfo $
             targetComponent tgtInfo
     leafRule_maybe (rId, r) =
-      if any ((r `ruleOutputsLocation`) . (compAutogenDir,)) autogenModPaths
+      if any ((r `ruleOutputsLocation`) . (Location compAutogenDir)) autogenModPaths
         then vertexFromRuleId rId
         else Nothing
     leafRules = mapMaybe leafRule_maybe $ Map.toList allRules
@@ -927,7 +925,10 @@ executeRulesUserOrSystem scope runDepsCmdData runCmdData verbosity lbi tgtInfo a
         warn verbosity $
           unlines $
             "The following rules are not demanded and will not be run:"
-              : [ "  - " ++ show rId ++ ", generating " ++ showLocs (NE.toList $ results r)
+              : concat
+                [ [ "  - " ++ show rId ++ ","
+                  , "    generating " ++ show (NE.toList $ results r)
+                  ]
                 | v <- Set.toList nonDemandedRuleVerts
                 , let (r, rId, _) = ruleFromVertex v
                 ]
@@ -935,7 +936,8 @@ executeRulesUserOrSystem scope runDepsCmdData runCmdData verbosity lbi tgtInfo a
                  , "  - Some autogenerated modules were not declared"
                  , "    (in the package description or in the pre-configure hooks)"
                  , "  - The output location for an autogenerated module is incorrect,"
-                 , "    (e.g. it is not in the appropriate 'autogenComponentModules' directory)"
+                 , "    (e.g. the file extension is incorrect, or"
+                 , "     it is not in the appropriate 'autogenComponentModules' directory)"
                  ]
 
       -- Run all the demanded rules, in dependency order.
@@ -955,7 +957,7 @@ executeRulesUserOrSystem scope runDepsCmdData runCmdData verbosity lbi tgtInfo a
               allDeps = staticDeps ++ fromMaybe [] (fst <$> mbDyn)
           -- Check that the dependencies the rule expects are indeed present.
           resolvedDeps <- traverse (resolveDependency verbosity rId allRules) allDeps
-          missingRuleDeps <- filterM missingDep resolvedDeps
+          missingRuleDeps <- filterM (missingDep mbWorkDir) resolvedDeps
           case NE.nonEmpty missingRuleDeps of
             Just missingDeps ->
               errorOut $ CantFindSourceForRuleDependencies (toRuleBinary r) missingDeps
@@ -965,7 +967,7 @@ executeRulesUserOrSystem scope runDepsCmdData runCmdData verbosity lbi tgtInfo a
               runCmdData rId execCmd
               -- Throw an error if running the action did not result in
               -- the generation of outputs that we expected it to.
-              missingRuleResults <- filterM missingDep $ NE.toList reslts
+              missingRuleResults <- filterM (missingDep mbWorkDir) $ NE.toList reslts
               for_ (NE.nonEmpty missingRuleResults) $ \missingResults ->
                 errorOut $ MissingRuleOutputs (toRuleBinary r) missingResults
               return ()
@@ -975,7 +977,8 @@ executeRulesUserOrSystem scope runDepsCmdData runCmdData verbosity lbi tgtInfo a
       SUser -> ruleBinary
       SSystem -> id
     clbi = targetCLBI tgtInfo
-    compAutogenDir = getSymbolicPath $ autogenComponentModulesDir lbi clbi
+    mbWorkDir = mbWorkDirLBI lbi
+    compAutogenDir = autogenComponentModulesDir lbi clbi
     errorOut e =
       dieWithException verbosity $
         SetupHooksException $
@@ -1016,11 +1019,14 @@ ruleOutputsLocation (Rule{results = rs}) fp =
   any (\out -> normaliseLocation out == normaliseLocation fp) rs
 
 normaliseLocation :: Location -> Location
-normaliseLocation (base, rel) = (normalise base, normalise rel)
+normaliseLocation (Location base rel) =
+  Location (normaliseSymbolicPath base) (normaliseSymbolicPath rel)
 
 -- | Is the file we depend on missing?
-missingDep :: Location -> IO Bool
-missingDep (base, fp) = not <$> doesFileExist (base </> fp)
+missingDep :: Maybe (SymbolicPath CWD (Dir Pkg)) -> Location -> IO Bool
+missingDep mbWorkDir loc = not <$> doesFileExist fp
+  where
+    fp = interpretSymbolicPath mbWorkDir (location loc)
 
 --------------------------------------------------------------------------------
 -- Compatibility with HookedBuildInfo.
diff --git a/Cabal/src/Distribution/Simple/SetupHooks/Rule.hs b/Cabal/src/Distribution/Simple/SetupHooks/Rule.hs
index afbabb859f6..e75d2c29f89 100644
--- a/Cabal/src/Distribution/Simple/SetupHooks/Rule.hs
+++ b/Cabal/src/Distribution/Simple/SetupHooks/Rule.hs
@@ -14,6 +14,7 @@
 {-# LANGUAGE MultiWayIf #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE PolyKinds #-}
 {-# LANGUAGE QuantifiedConstraints #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
@@ -65,7 +66,8 @@ module Distribution.Simple.SetupHooks.Rule
   , noRules
 
     -- ** Rule inputs/outputs
-  , Location
+  , Location (..)
+  , location
 
     -- ** File/directory monitoring
   , MonitorFilePath (..)
@@ -95,9 +97,22 @@ import Distribution.ModuleName
   )
 import Distribution.Simple.FileMonitor.Types
 import Distribution.Types.UnitId
+import Distribution.Utils.Path
+  ( FileOrDir (..)
+  , Pkg
+  , RelativePath
+  , SymbolicPath
+  , getSymbolicPath
+  , (</>)
+  )
 import Distribution.Utils.ShortText
   ( ShortText
   )
+import Distribution.Utils.Structured
+  ( Structure (..)
+  , Structured (..)
+  , nominalStructure
+  )
 import Distribution.Verbosity
   ( Verbosity
   )
@@ -130,8 +145,13 @@ import Data.Type.Equality
   ( (:~~:) (HRefl)
   , type (==)
   )
-import GHC.Show (showCommaSpace)
+import GHC.Show
+  ( showCommaSpace
+  )
 import GHC.StaticPtr
+import GHC.TypeLits
+  ( Symbol
+  )
 import System.IO.Unsafe
   ( unsafePerformIO
   )
@@ -145,6 +165,10 @@ import qualified Type.Reflection as Typeable
   , pattern App
   )
 
+import System.FilePath
+  ( normalise
+  )
+
 --------------------------------------------------------------------------------
 
 {- Note [Fine-grained hooks]
@@ -254,7 +278,7 @@ deriving anyclass instance Binary (RuleData System)
 -- | Trimmed down 'Show' instance, mostly for error messages.
 instance Show RuleBinary where
   show (Rule{staticDependencies = deps, results = reslts, ruleCommands = cmds}) =
-    what ++ ": " ++ showDeps deps ++ " --> " ++ showLocs (NE.toList reslts)
+    what ++ ": " ++ showDeps deps ++ " --> " ++ show (NE.toList reslts)
     where
       what = case cmds of
         StaticRuleCommand{} -> "Rule"
@@ -266,8 +290,6 @@ instance Show RuleBinary where
         RuleDependency (RuleOutput{outputOfRule = rId, outputIndex = i}) ->
           "(" ++ show rId ++ ")[" ++ show i ++ "]"
         FileDependency loc -> show loc
-      showLocs :: [Location] -> String
-      showLocs locs = "[" ++ intercalate ", " (map show locs) ++ "]"
 
 -- | A rule with static dependencies.
 --
@@ -322,13 +344,60 @@ dynamicRule dict depsCmd action dep res =
 -- consisting of a base directory and of a file path relative to that base
 -- directory path.
 --
--- In practice, this will be something like @( dir, toFilePath modName )@,
+-- In practice, this will be something like @'Location' dir ('moduleNameSymbolicPath' mod <.> "hs")@,
 -- where:
 --
 --  - for a file dependency, @dir@ is one of the Cabal search directories,
 --  - for an output, @dir@ is a directory such as @autogenComponentModulesDir@
 --    or @componentBuildDir@.
-type Location = (FilePath, FilePath)
+data Location where
+  Location
+    :: { locationBaseDir :: !(SymbolicPath Pkg (Dir baseDir))
+        -- ^ Base directory.
+       , locationRelPath :: !(RelativePath baseDir File)
+        -- ^ File path relative to base directory (including file extension).
+       }
+    -> Location
+
+instance Eq Location where
+  Location b1 l1 == Location b2 l2 =
+    (getSymbolicPath b1 == getSymbolicPath b2)
+      && (getSymbolicPath l1 == getSymbolicPath l2)
+instance Ord Location where
+  compare (Location b1 l1) (Location b2 l2) =
+    compare
+      (getSymbolicPath b1, getSymbolicPath l1)
+      (getSymbolicPath b2, getSymbolicPath l2)
+instance Binary Location where
+  put (Location base loc) = put (base, loc)
+  get = Location <$> get <*> get
+instance Structured Location where
+  structure _ =
+    Structure
+      tr
+      0
+      (show tr)
+      [
+        ( "Location"
+        ,
+          [ nominalStructure $ Proxy @(SymbolicPath Pkg (Dir (Tok "baseDir")))
+          , nominalStructure $ Proxy @(RelativePath (Tok "baseDir") File)
+          ]
+        )
+      ]
+    where
+      tr = Typeable.SomeTypeRep $ Typeable.typeRep @Location
+
+-- | Get a (relative or absolute) un-interpreted path to a 'Location'.
+location :: Location -> SymbolicPath Pkg File
+location (Location base rel) = base </> rel
+
+instance Show Location where
+  showsPrec p (Location base rel) =
+    showParen (p > 5) $
+      showString (normalise $ getSymbolicPath base)
+        . showString " </> "
+        . showString (normalise $ getSymbolicPath rel)
 
 -- The reason for splitting it up this way is that some pre-processors don't
 -- simply generate one output @.hs@ file from one input file, but have
@@ -1015,6 +1084,10 @@ instance
                                   }
           _ -> error "internal error when decoding dynamic rule commands"
 
+-- | A token constructor used to define 'Structured' instances on types
+-- that involve existential quantification.
+data family Tok (arg :: Symbol) :: k
+
 instance
   ( forall res. Binary (ruleCmd System LBS.ByteString res)
   , Binary (deps System LBS.ByteString LBS.ByteString)
diff --git a/cabal-testsuite/PackageTests/BuildToolPaths/pbts/SetupHooks.hs b/cabal-testsuite/PackageTests/BuildToolPaths/pbts/SetupHooks.hs
index 1386a6ad3c2..478d7af2f5d 100644
--- a/cabal-testsuite/PackageTests/BuildToolPaths/pbts/SetupHooks.hs
+++ b/cabal-testsuite/PackageTests/BuildToolPaths/pbts/SetupHooks.hs
@@ -38,15 +38,12 @@ import Distribution.Types.Component
 import Distribution.Types.LocalBuildInfo
   ( withPrograms )
 import Distribution.Utils.Path
-  ( SymbolicPath, FileOrDir(Dir), CWD, Pkg
-  , getSymbolicPath, moduleNameSymbolicPath
-  )
 import Distribution.Utils.ShortText
   ( toShortText )
 
 -- filepath
 import System.FilePath
-  ( (</>), replaceExtension, takeDirectory, takeExtension )
+  ( takeExtension )
 
 --------------------------------------------------------------------------------
 
@@ -120,7 +117,7 @@ preBuildRules
               Just ( base, rel ) ->
                 return $
                   Just
-                    ( md, ( getSymbolicPath base, getSymbolicPath rel ) )
+                    ( md, Location base rel )
               Nothing ->
                 return Nothing
       let ppMods = catMaybes ppMbMods
@@ -131,23 +128,27 @@ preBuildRules
     -- above search (it would be nice to be able to use findFileWithExtensionMonitored).
 
     -- 5. Declare a rule for each custom-pp module that runs the pre-processor.
-      for_ ppMods $ \ ( md, inputLoc@( _inputBaseDir, inputRelPath ) ) -> do
-        let ext = takeExtension inputRelPath
+      for_ ppMods $ \ ( md, inputLoc@(Location _inputBaseDir inputRelPath ) ) -> do
+        let ext = takeExtension $ getSymbolicPath inputRelPath
             customPp = case ext of
               ".hs-pp1" -> customPp1
               ".hs-pp2" -> customPp2
               _ -> error $ "internal error: unhandled extension " ++ ext
-            outputBaseLoc = getSymbolicPath $ autogenComponentModulesDir lbi clbi
-            outputLoc = ( outputBaseLoc, replaceExtension inputRelPath "hs" )
+            outputBaseLoc = autogenComponentModulesDir lbi clbi
+            outputLoc =
+              Location
+                outputBaseLoc
+                ( unsafeCoerceSymbolicPath $ replaceExtensionSymbolicPath inputRelPath "hs" )
         registerRule_ ( toShortText $ show md ) $
           staticRule ( ppCmd customPp inputLoc outputLoc ) [] ( outputLoc NE.:| [] )
 
 ppModule :: ( Verbosity, Maybe (SymbolicPath CWD (Dir Pkg)), ConfiguredProgram, Location, Location ) -> IO ()
-ppModule ( verbosity, mbWorkDir, customPp, ( inputBaseDir, inputRelPath ), ( outputBaseDir, outputRelPath ) ) = do
-  let inputPath  = inputBaseDir </> inputRelPath
-      outputPath = outputBaseDir </> outputRelPath
-  createDirectoryIfMissingVerbose verbosity True $ takeDirectory outputPath
-  runProgramCwd verbosity mbWorkDir customPp [ inputPath, outputPath ]
+ppModule ( verbosity, mbWorkDir, customPp, inputLoc, outputLoc ) = do
+  let inputPath  = location inputLoc
+      outputPath = location outputLoc
+  createDirectoryIfMissingVerbose verbosity True $
+    interpretSymbolicPath mbWorkDir (takeDirectorySymbolicPath outputPath)
+  runProgramCwd verbosity mbWorkDir customPp [ getSymbolicPath inputPath, getSymbolicPath outputPath ]
 
 componentModules :: Component -> [ ModuleName ]
 componentModules comp = libMods ++ otherModules ( componentBuildInfo comp )
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksC2HsRules/SetupHooks.hs b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksC2HsRules/SetupHooks.hs
index 67ac7b8ee1d..2e3bcf4a818 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksC2HsRules/SetupHooks.hs
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksC2HsRules/SetupHooks.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DeriveAnyClass #-}
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE DerivingStrategies #-}
@@ -15,6 +16,7 @@ import Distribution.ModuleName
 import Distribution.Simple.LocalBuildInfo (interpretSymbolicPathLBI)
 import Distribution.Simple.SetupHooks
 import Distribution.Simple.Utils
+import Distribution.Utils.Path
 
 import Data.Foldable ( for_ )
 import Data.List ( isPrefixOf )
@@ -24,7 +26,6 @@ import Data.Traversable ( for )
 import GHC.Generics
 
 import qualified Data.Map as Map
-import System.FilePath
 
 setupHooks :: SetupHooks
 setupHooks =
@@ -39,12 +40,11 @@ preBuildRules :: PreBuildComponentInputs -> RulesM ()
 preBuildRules (PreBuildComponentInputs { buildingWhat = what, localBuildInfo = lbi, targetInfo = tgt }) = mdo
   let verbosity = buildingWhatVerbosity what
       clbi = targetCLBI tgt
-      i = interpretSymbolicPathLBI lbi
-      autogenDir = i (autogenComponentModulesDir lbi clbi)
-      buildDir = i (componentBuildDir lbi clbi)
+      autogenDir = autogenComponentModulesDir lbi clbi
+      buildDir = componentBuildDir lbi clbi
 
       computeC2HsDepsAction (C2HsDepsInput {..}) = do
-        importLine : _srcLines <- lines <$> readFile (inDir </> toFilePath modNm <.> "myChs")
+        importLine : _srcLines <- lines <$> readFile (getSymbolicPath $ inDir </> moduleNameSymbolicPath modNm <.> "myChs")
         let imports :: [ModuleName]
             imports
               | "imports:" `isPrefixOf` importLine
@@ -60,24 +60,24 @@ preBuildRules (PreBuildComponentInputs { buildingWhat = what, localBuildInfo = l
           , imports )
 
       runC2HsAction (C2HsInput {..}) importModNms = do
-        let modPath = toFilePath modNm
+        let modPath = moduleNameSymbolicPath modNm
         warn verbosity $ "Running C2Hs on " ++ modName modNm ++ ".myChs.\n C2Hs dependencies: " ++ modNames importModNms
-        _importLine : srcLines <- lines <$> readFile (inDir </> modPath <.> "myChs")
+        _importLine : srcLines <- lines <$> readFile (getSymbolicPath $ inDir </> modPath <.> "myChs")
 
-        rewriteFileEx verbosity (hsDir </> modPath <.> "hs") $
+        rewriteFileEx verbosity (getSymbolicPath $ hsDir </> modPath <.> "hs") $
           unlines $ ("module " ++ modName modNm ++ " where\n") :
             (map ( ( "import " ++ ) . modName ) importModNms ++ srcLines)
-        rewriteFileEx verbosity (chiDir </> modPath <.> "myChi") ""
+        rewriteFileEx verbosity (getSymbolicPath $ chiDir </> unsafeCoerceSymbolicPath modPath <.> "myChi") ""
 
       mkRule modNm =
         dynamicRule (static Dict)
           (mkCommand (static Dict) (static computeC2HsDepsAction) $ C2HsDepsInput { ruleIds = modToRuleId, ..})
           (mkCommand (static Dict) (static runC2HsAction) $ C2HsInput {hsDir = autogenDir, chiDir = buildDir, ..})
-          [ FileDependency (inDir, modPath <.> "myChs") ]
-          ( ( autogenDir, modPath <.> "hs" ) NE.:| [ ( buildDir, modPath <.> "myChi" ) ] )
+          [ FileDependency $ Location inDir (modPath <.> "myChs") ]
+          ( Location autogenDir (modPath <.> "hs" ) NE.:| [ Location buildDir (unsafeCoerceSymbolicPath modPath <.> "myChi") ] )
         where
-          modPath = toFilePath modNm
-          inDir = "."
+          modPath = moduleNameSymbolicPath modNm
+          inDir = sameDirectory
 
   -- NB: in practice, we would get the module names by looking at the .cabal
   -- file and performing a search for `.chs` files on disk, but for this test
@@ -94,7 +94,7 @@ preBuildRules (PreBuildComponentInputs { buildingWhat = what, localBuildInfo = l
 data C2HsDepsInput
   = C2HsDepsInput
   { verbosity :: Verbosity
-  , inDir :: FilePath
+  , inDir :: SymbolicPath Pkg (Dir Source)
   , modNm :: ModuleName
   , ruleIds :: Map.Map ModuleName RuleId
   }
@@ -106,9 +106,9 @@ data C2HsInput
   = C2HsInput
   { verbosity :: Verbosity
   , modNm :: ModuleName
-  , inDir :: FilePath
-  , hsDir :: FilePath
-  , chiDir :: FilePath
+  , inDir :: SymbolicPath Pkg (Dir Source)
+  , hsDir :: SymbolicPath Pkg (Dir Source)
+  , chiDir :: SymbolicPath Pkg (Dir Build)
   }
   deriving stock ( Show, Generic )
   deriving anyclass Binary
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksCyclicRules/SetupHooks.hs b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksCyclicRules/SetupHooks.hs
index 65067ebff97..64920431b45 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksCyclicRules/SetupHooks.hs
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksCyclicRules/SetupHooks.hs
@@ -7,6 +7,7 @@ module SetupHooks where
 
 import Distribution.Simple.LocalBuildInfo (interpretSymbolicPathLBI)
 import Distribution.Simple.SetupHooks
+import Distribution.Utils.Path (makeRelativePathEx)
 
 import qualified Data.List.NonEmpty as NE ( NonEmpty(..) )
 
@@ -22,19 +23,18 @@ setupHooks =
 cyclicPreBuildRules :: PreBuildComponentInputs -> RulesM ()
 cyclicPreBuildRules (PreBuildComponentInputs { localBuildInfo = lbi, targetInfo = tgt }) = mdo
   let clbi = targetCLBI tgt
-      i = interpretSymbolicPathLBI lbi
-      autogenDir = i (autogenComponentModulesDir lbi clbi)
+      autogenDir = autogenComponentModulesDir lbi clbi
       action = mkCommand (static Dict) (static (\ () -> error "This should not run")) ()
   r1 <- registerRule "r1" $
     staticRule action
       [ RuleDependency $ RuleOutput r2 0 ]
-      ( ( autogenDir, "G1.hs" ) NE.:| [] )
+      ( Location autogenDir (makeRelativePathEx "G1.hs") NE.:| [] )
   r2 <- registerRule "r2" $
     staticRule action
       [ RuleDependency $ RuleOutput r1 0 ]
-      ( ( autogenDir, "G2.hs" ) NE.:| [] )
+      ( Location autogenDir (makeRelativePathEx "G2.hs") NE.:| [] )
   r3 <- registerRule "r3" $
     staticRule action
       [ RuleDependency $ RuleOutput r3 0 ]
-      ( ( autogenDir, "G3.hs" ) NE.:| [] )
+      ( Location autogenDir (makeRelativePathEx "G3.hs") NE.:| [] )
   return ()
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksCyclicRules/setup.out b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksCyclicRules/setup.out
index 5076d3b207b..0222d0aa947 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksCyclicRules/setup.out
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksCyclicRules/setup.out
@@ -3,9 +3,9 @@ Configuring setup-hooks-cyclic-rules-test-0.1.0.0...
 # Setup build
 Error: [Cabal-9077]
 Hooks: cycles in dependency structure of rules:
-  Rule: [(RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (18,59)}, ruleName = "r3"})[0]] --> [setup.dist/work/dist/build/autogen/G3.hs]
+  Rule: [(RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (19,59)}, ruleName = "r3"})[0]] --> [setup.dist/work/dist/build/autogen </> G3.hs]
 
-  Rule: [(RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (18,59)}, ruleName = "r2"})[0]] --> [setup.dist/work/dist/build/autogen/G1.hs]
+  Rule: [(RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (19,59)}, ruleName = "r2"})[0]] --> [setup.dist/work/dist/build/autogen </> G1.hs]
   |
-  `- Rule: [(RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (18,59)}, ruleName = "r1"})[0]] --> [setup.dist/work/dist/build/autogen/G2.hs]
+  `- Rule: [(RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (19,59)}, ruleName = "r1"})[0]] --> [setup.dist/work/dist/build/autogen </> G2.hs]
 
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksDuplicateRuleId/SetupHooks.hs b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksDuplicateRuleId/SetupHooks.hs
index b7ac707e627..2387cfaba92 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksDuplicateRuleId/SetupHooks.hs
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksDuplicateRuleId/SetupHooks.hs
@@ -6,6 +6,7 @@
 module SetupHooks where
 
 import Distribution.Simple.SetupHooks
+import Distribution.Utils.Path (sameDirectory, makeRelativePathEx)
 
 import qualified Data.List.NonEmpty as NE ( NonEmpty(..) )
 
@@ -21,5 +22,5 @@ setupHooks =
 dupRuleIdRules :: PreBuildComponentInputs -> RulesM ()
 dupRuleIdRules _ = do
   let cmd = mkCommand (static Dict) (static (\ _ -> error "This should not run")) ()
-  registerRule_ "myRule" $ staticRule cmd [] ( ( "src", "A.hs" ) NE.:| [] )
-  registerRule_ "myRule" $ staticRule cmd [] ( ( "src", "B.hs" ) NE.:| [] )
+  registerRule_ "myRule" $ staticRule cmd [] ( Location sameDirectory (makeRelativePathEx "A.hs") NE.:| [] )
+  registerRule_ "myRule" $ staticRule cmd [] ( Location sameDirectory (makeRelativePathEx "B.hs") NE.:| [] )
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksDuplicateRuleId/setup.out b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksDuplicateRuleId/setup.out
index 2a5f2e99d6f..f46cdd89acc 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksDuplicateRuleId/setup.out
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksDuplicateRuleId/setup.out
@@ -2,6 +2,6 @@
 Configuring setup-hooks-duplicate-rule-id-test-0.1.0.0...
 # Setup build
 Error: [Cabal-7717]
-Duplicate pre-build rule (RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (17,59)}, ruleName = "myRule"})
-  - Rule: [] --> [src/A.hs]
-  - Rule: [] --> [src/B.hs]
+Duplicate pre-build rule (RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (18,59)}, ruleName = "myRule"})
+  - Rule: [] --> [. </> A.hs]
+  - Rule: [] --> [. </> B.hs]
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksInvalidRuleOutputIndex/SetupHooks.hs b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksInvalidRuleOutputIndex/SetupHooks.hs
index 0949aff5b89..56db5f98f13 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksInvalidRuleOutputIndex/SetupHooks.hs
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksInvalidRuleOutputIndex/SetupHooks.hs
@@ -7,10 +7,10 @@ module SetupHooks where
 
 import Distribution.Simple.LocalBuildInfo (interpretSymbolicPathLBI)
 import Distribution.Simple.SetupHooks
-import Distribution.Simple.Utils ( rewriteFileEx )
+import Distribution.Simple.Utils (rewriteFileEx)
+import Distribution.Utils.Path
 
 import qualified Data.List.NonEmpty as NE ( NonEmpty(..) )
-import System.FilePath
 
 setupHooks :: SetupHooks
 setupHooks =
@@ -24,11 +24,10 @@ setupHooks =
 invalidRuleOutputIndexRules :: PreBuildComponentInputs -> RulesM ()
 invalidRuleOutputIndexRules (PreBuildComponentInputs { buildingWhat = what, localBuildInfo = lbi, targetInfo = tgt }) = do
   let clbi = targetCLBI tgt
-      i = interpretSymbolicPathLBI lbi
-      autogenDir = i (autogenComponentModulesDir lbi clbi)
+      autogenDir = autogenComponentModulesDir lbi clbi
       verbosity = buildingWhatVerbosity what
       action = mkCommand (static Dict) $ static (\ ((dir, modNm), verb) -> do
-        let loc = dir </> modNm <.> "hs"
+        let loc = getSymbolicPath dir </> modNm <.> "hs"
         rewriteFileEx verb loc $
           "module " ++ modNm ++ " where {}"
         )
@@ -36,8 +35,8 @@ invalidRuleOutputIndexRules (PreBuildComponentInputs { buildingWhat = what, loca
   r1 <- registerRule "r1" $
           staticRule
             (action ((autogenDir, "A"), verbosity))
-            [] ( ( autogenDir, "A.hs" ) NE.:| [] )
+            [] ( Location autogenDir (makeRelativePathEx "A.hs") NE.:| [] )
   registerRule_ "r2" $
     staticRule (action ((autogenDir, "B"), verbosity))
       [ RuleDependency $ RuleOutput r1 7 ]
-      ( ( autogenDir, "B.hs" ) NE.:| [] )
+      ( Location autogenDir (makeRelativePathEx "B.hs") NE.:| [] )
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleDep/SetupHooks.hs b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleDep/SetupHooks.hs
index 47ff3296163..1f1adcf7ab1 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleDep/SetupHooks.hs
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleDep/SetupHooks.hs
@@ -6,6 +6,7 @@ module SetupHooks where
 
 import Distribution.Simple.LocalBuildInfo (interpretSymbolicPathLBI)
 import Distribution.Simple.SetupHooks
+import Distribution.Utils.Path (sameDirectory, makeRelativePathEx)
 
 import qualified Data.List.NonEmpty as NE ( NonEmpty(..) )
 
@@ -21,10 +22,9 @@ setupHooks =
 missingDepRules :: PreBuildComponentInputs -> RulesM ()
 missingDepRules (PreBuildComponentInputs { localBuildInfo = lbi, targetInfo = tgt }) = do
   let clbi = targetCLBI tgt
-      i = interpretSymbolicPathLBI lbi
-      autogenDir = i (autogenComponentModulesDir lbi clbi)
+      autogenDir = autogenComponentModulesDir lbi clbi
       action = mkCommand (static Dict) (static (\ _ -> error "This should not run")) ()
   registerRule_ "r" $
     staticRule action
-      [ FileDependency ( ".", "Missing.hs" ) ]
-      ( ( autogenDir, "G.hs" ) NE.:| [] )
+      [ FileDependency $ Location sameDirectory (makeRelativePathEx "Missing.hs") ]
+      ( Location autogenDir (makeRelativePathEx "G.hs") NE.:| [] )
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleDep/setup.out b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleDep/setup.out
index bfbd911994d..c95e66def0c 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleDep/setup.out
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleDep/setup.out
@@ -3,4 +3,4 @@ Configuring setup-hooks-missing-rule-dep-test-0.1.0.0...
 # Setup build
 Error: [Cabal-1071]
 Pre-build rules: can't find source for rule dependency:
-  - Missing.hs
+  - . </> Missing.hs
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleRes/SetupHooks.hs b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleRes/SetupHooks.hs
index 6b5ce60dd81..4223ee4385f 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleRes/SetupHooks.hs
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleRes/SetupHooks.hs
@@ -6,6 +6,7 @@ module SetupHooks where
 
 import Distribution.Simple.LocalBuildInfo (interpretSymbolicPathLBI)
 import Distribution.Simple.SetupHooks
+import Distribution.Utils.Path (makeRelativePathEx)
 
 import qualified Data.List.NonEmpty as NE ( NonEmpty(..) )
 
@@ -21,10 +22,9 @@ setupHooks =
 missingResRules :: PreBuildComponentInputs -> RulesM ()
 missingResRules (PreBuildComponentInputs { localBuildInfo = lbi, targetInfo = tgt }) = do
   let clbi = targetCLBI tgt
-      i = interpretSymbolicPathLBI lbi
-      autogenDir = i (autogenComponentModulesDir lbi clbi)
+      autogenDir = autogenComponentModulesDir lbi clbi
       action = mkCommand (static Dict) (static (\ _ -> return ())) ()
   registerRule_ "r" $
     staticRule action
       [ ]
-      ( ( autogenDir, "G.hs" ) NE.:| [] )
+      ( Location autogenDir (makeRelativePathEx "G.hs") NE.:| [] )
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleRes/setup.out b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleRes/setup.out
index 5659bca63e1..1e0fd56bb6f 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleRes/setup.out
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksMissingRuleRes/setup.out
@@ -3,4 +3,4 @@ Configuring setup-hooks-missing-rule-res-test-0.1.0.0...
 # Setup build
 Error: [Cabal-3498]
 Pre-build rule did not generate expected result:
-  - setup.dist/work/dist/build/autogen/G.hs
+  - setup.dist/work/dist/build/autogen </> G.hs
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksRuleOrdering/SetupHooks.hs b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksRuleOrdering/SetupHooks.hs
index a301e71cff0..e15c3ae2ead 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksRuleOrdering/SetupHooks.hs
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksRuleOrdering/SetupHooks.hs
@@ -9,14 +9,12 @@ module SetupHooks where
 import Distribution.Simple.LocalBuildInfo (interpretSymbolicPathLBI)
 import Distribution.Simple.SetupHooks
 import Distribution.Simple.Utils ( rewriteFileEx, warn )
+import Distribution.Utils.Path
 
 import Data.Foldable ( for_ )
 import qualified Data.List.NonEmpty as NE ( NonEmpty(..) )
 import Data.Traversable ( for )
 
-import System.FilePath
-  ( (<.>), (</>) )
-
 setupHooks :: SetupHooks
 setupHooks =
   noSetupHooks
@@ -37,25 +35,28 @@ preBuildRules :: PreBuildComponentInputs -> RulesM ()
 preBuildRules (PreBuildComponentInputs { buildingWhat = what, localBuildInfo = lbi, targetInfo = tgt }) = mdo
   let verbosity = buildingWhatVerbosity what
       clbi = targetCLBI tgt
-      i = interpretSymbolicPathLBI lbi
-      autogenDir = i (autogenComponentModulesDir lbi clbi)
+      autogenDir = autogenComponentModulesDir lbi clbi
 
       mkAction =
         mkCommand (static Dict) $ static (\ (dir, verb, (inMod, outMod)) -> do
           warn verb $ "Running rule: " ++ inMod ++ " --> " ++ outMod
-          let loc = dir </> outMod <.> "hs"
+          let loc = getSymbolicPath dir </> outMod <.> "hs"
           rewriteFileEx verb loc $
             "module " ++ outMod ++ " where { import " ++ inMod ++ " }"
         )
 
-      actionArg inMod outMod = (autogenDir, verbosity, (inMod, outMod))
+      actionArg inMod outMod =
+        (autogenDir, verbosity, (inMod, outMod))
 
       mkRule action input outMod =
         staticRule action
           [ input ]
-          ( ( autogenDir, outMod <.> "hs" ) NE.:| [] )
-
-  r1 <- registerRule "r1" $ mkRule (mkAction (actionArg "B" "C")) (RuleDependency $ RuleOutput r2 0) "C" -- B --> C
-  r2 <- registerRule "r2" $ mkRule (mkAction (actionArg "A" "B")) (FileDependency (".", "A.hs"))     "B" -- A --> B
-  r3 <- registerRule "r3" $ mkRule (mkAction (actionArg "C" "D")) (RuleDependency $ RuleOutput r1 0) "D" -- C --> D
+          ( Location autogenDir (makeRelativePathEx outMod <.> "hs") NE.:| [] )
+
+  -- B --> C
+  -- A --> B
+  -- C --> D
+  r1 <- registerRule "r1" $ mkRule (mkAction (actionArg "B" "C")) (RuleDependency $ RuleOutput r2 0) "C"
+  r2 <- registerRule "r2" $ mkRule (mkAction (actionArg "A" "B")) (FileDependency $ Location sameDirectory (makeRelativePathEx "A.hs")) "B"
+  r3 <- registerRule "r3" $ mkRule (mkAction (actionArg "C" "D")) (RuleDependency $ RuleOutput r1 0) "D"
   return ()
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksUnusedRules/SetupHooks.hs b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksUnusedRules/SetupHooks.hs
index e1d2141aa61..bae5ace431d 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksUnusedRules/SetupHooks.hs
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksUnusedRules/SetupHooks.hs
@@ -7,6 +7,7 @@ module SetupHooks where
 
 import Distribution.Simple.LocalBuildInfo (interpretSymbolicPathLBI)
 import Distribution.Simple.SetupHooks
+import Distribution.Utils.Path (makeRelativePathEx)
 
 import qualified Data.List.NonEmpty as NE ( NonEmpty(..) )
 
@@ -22,12 +23,11 @@ setupHooks =
 unusedPreBuildRules :: PreBuildComponentInputs -> RulesM ()
 unusedPreBuildRules (PreBuildComponentInputs { localBuildInfo = lbi, targetInfo = tgt }) = do
   let clbi = targetCLBI tgt
-      i = interpretSymbolicPathLBI lbi
-      autogenDir = i (autogenComponentModulesDir lbi clbi)
+      autogenDir = autogenComponentModulesDir lbi clbi
       action = mkCommand (static Dict) (static (\ _ -> error "This should not run")) ()
   registerRule_ "r1" $
     staticRule action []
-      ( ( autogenDir, "X.hs" ) NE.:| [ ( autogenDir, "Y.hs" ) ] )
+      ( Location autogenDir (makeRelativePathEx "X.hs") NE.:| [ Location autogenDir (makeRelativePathEx "Y.hs") ] )
   registerRule_ "r2" $
     staticRule action []
-      ( ( autogenDir, "Z.what" ) NE.:| [] )
+      ( Location autogenDir (makeRelativePathEx "Z.hs") NE.:| [] )
diff --git a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksUnusedRules/setup.out b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksUnusedRules/setup.out
index b5b0f048ce6..47872b4f83d 100644
--- a/cabal-testsuite/PackageTests/SetupHooks/SetupHooksUnusedRules/setup.out
+++ b/cabal-testsuite/PackageTests/SetupHooks/SetupHooksUnusedRules/setup.out
@@ -2,12 +2,15 @@
 Configuring setup-hooks-unused-rules-test-0.1.0.0...
 # Setup build
 Warning: The following rules are not demanded and will not be run:
-  - RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (18,59)}, ruleName = "r1"}, generating [setup.dist/work/dist/build/autogen/X.hs, setup.dist/work/dist/build/autogen/Y.hs]
-  - RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (18,59)}, ruleName = "r2"}, generating [setup.dist/work/dist/build/autogen/Z.what]
+  - RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (19,59)}, ruleName = "r1"},
+    generating [setup.dist/work/dist/build/autogen </> X.hs,setup.dist/work/dist/build/autogen </> Y.hs]
+  - RuleId {ruleNameSpace = RulesNameSpace {rulesUnitId = UnitId "main", rulesModuleName = ModuleName "SetupHooks", rulesSrcLoc = (19,59)}, ruleName = "r2"},
+    generating [setup.dist/work/dist/build/autogen </> Z.hs]
 Possible reasons for this error:
   - Some autogenerated modules were not declared
     (in the package description or in the pre-configure hooks)
   - The output location for an autogenerated module is incorrect,
-    (e.g. it is not in the appropriate 'autogenComponentModules' directory)
+    (e.g. the file extension is incorrect, or
+     it is not in the appropriate 'autogenComponentModules' directory)
 Preprocessing library for setup-hooks-unused-rules-test-0.1.0.0...
 Building library for setup-hooks-unused-rules-test-0.1.0.0...