diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 0.14.2 - 2021-02-19
+
+- Pass `default-language` to `doctest`
+- Support local `.tar.gz` tarballs in `packages:`.
+
 ## 0.14 - 2022-01-05
 
 - Add GHC-9.0 releases and GHC-9.2.1
diff --git a/haskell-ci.cabal b/haskell-ci.cabal
--- a/haskell-ci.cabal
+++ b/haskell-ci.cabal
@@ -1,6 +1,6 @@
 cabal-version:      2.2
 name:               haskell-ci
-version:            0.14
+version:            0.14.2
 synopsis:           Cabal package script generator for Travis-CI
 description:
   Script generator (@haskell-ci@) for
@@ -157,7 +157,7 @@
     , attoparsec                     ^>=0.14.1
     , base-compat                    ^>=0.11 || ^>=0.12
     , base16-bytestring              ^>=1.0.1.0
-    , cabal-install-parsers          ^>=0.4.4
+    , cabal-install-parsers          ^>=0.4.5
     , cryptohash-sha256              ^>=0.11.101.0
     , exceptions                     ^>=0.10.0
     , generic-lens-lite              ^>=0.1
diff --git a/src/HaskellCI/Auxiliary.hs b/src/HaskellCI/Auxiliary.hs
--- a/src/HaskellCI/Auxiliary.hs
+++ b/src/HaskellCI/Auxiliary.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE MultiWayIf        #-}
 {-# LANGUAGE NamedFieldPuns    #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RecordWildCards   #-}
@@ -18,6 +19,7 @@
 import qualified Distribution.Pretty                          as C
 import qualified Distribution.Types.GenericPackageDescription as C
 import qualified Distribution.Types.VersionRange              as C
+import qualified Network.URI                                  as URI
 import qualified Text.PrettyPrint                             as PP
 
 import Cabal.Optimization
@@ -26,8 +28,8 @@
 import HaskellCI.Compiler
 import HaskellCI.Config
 import HaskellCI.Config.CopyFields
-import HaskellCI.Config.Doctest
 import HaskellCI.Config.Docspec
+import HaskellCI.Config.Doctest
 import HaskellCI.Jobs
 import HaskellCI.List
 import HaskellCI.Package
@@ -41,7 +43,7 @@
     , docspecEnabled          :: Bool
     , hasTests                :: CompilerRange
     , hasLibrary              :: Bool
-    , extraCabalProjectFields :: [C.PrettyField ()]
+    , extraCabalProjectFields :: FilePath -> [C.PrettyField ()]
     , testShowDetails         :: String
     }
 
@@ -69,11 +71,13 @@
 
     hasLibrary = any (\Pkg{pkgGpd} -> isJust $ C.condLibrary pkgGpd) pkgs
 
-    extraCabalProjectFields :: [C.PrettyField ()]
-    extraCabalProjectFields = buildList $ do
+    extraCabalProjectFields :: FilePath -> [C.PrettyField ()]
+    extraCabalProjectFields rootdir = buildList $ do
         -- generate package fields for URI packages.
         for_ uris $ \uri ->
-            item $ C.PrettyField () "packages" $ PP.text $ uriToString id uri ""
+            item $ C.PrettyField () "packages" $ PP.text $ if
+                | URI.uriScheme uri == "file:" -> rootdir ++ URI.uriPath uri
+                | otherwise                    -> uriToString id uri ""
 
         -- copy fields from original cabal.project
         case cfgCopyFields of
diff --git a/src/HaskellCI/Bash.hs b/src/HaskellCI/Bash.hs
--- a/src/HaskellCI/Bash.hs
+++ b/src/HaskellCI/Bash.hs
@@ -104,7 +104,7 @@
                     ]
 
             -- extra cabal.project fields
-            cat "cabal.project" $ C.showFields' (const []) (const id) 2 extraCabalProjectFields
+            cat "cabal.project" $ C.showFields' (const []) (const id) 2 $ extraCabalProjectFields ""
 
             -- also write cabal.project.local file with
             -- @
diff --git a/src/HaskellCI/Config.hs b/src/HaskellCI/Config.hs
--- a/src/HaskellCI/Config.hs
+++ b/src/HaskellCI/Config.hs
@@ -142,7 +142,11 @@
     <*> C.optionalField       "jobs"                                                          (field @"cfgJobs")
         ^^^ metahelp "JOBS" "jobs (N:M - cabal:ghc)"
     <*> C.optionalFieldDef    "distribution"                                                  (field @"cfgUbuntu") Bionic
-        ^^^ metahelp "DIST" "distribution version (xenial, bionic)"
+        ^^^ metahelp "DIST" (concat
+              [ "distribution version ("
+              , intercalate ", " $ map showUbuntu [minBound..maxBound]
+              , ")"
+              ])
     <*> C.optionalFieldDef    "jobs-selection"                                                (field @"cfgTestedWith") TestedWithUniform
         ^^^ metahelp "uniform|any" "Jobs selection across packages"
     <*> rangeField            "enabled"                                                       (field @"cfgEnabledJobs") anyVersion
diff --git a/src/HaskellCI/Config/Ubuntu.hs b/src/HaskellCI/Config/Ubuntu.hs
--- a/src/HaskellCI/Config/Ubuntu.hs
+++ b/src/HaskellCI/Config/Ubuntu.hs
@@ -7,7 +7,7 @@
 import qualified Text.PrettyPrint    as PP
 
 data Ubuntu = Xenial | Bionic | Focal
-  deriving (Eq, Ord, Show)
+  deriving (Eq, Ord, Show, Enum, Bounded)
 
 instance C.Parsec Ubuntu where
     parsec = do
diff --git a/src/HaskellCI/GitHub.hs b/src/HaskellCI/GitHub.hs
--- a/src/HaskellCI/GitHub.hs
+++ b/src/HaskellCI/GitHub.hs
@@ -405,7 +405,7 @@
                     ]
 
             -- extra cabal.project fields
-            cat "cabal.project" $ C.showFields' (const []) (const id) 2 extraCabalProjectFields
+            cat "cabal.project" $ C.showFields' (const []) (const id) 2 $ extraCabalProjectFields "$GITHUB_WORKSPACE/source/"
 
             -- If using head.hackage, allow building with newer versions of GHC boot libraries.
             -- Note that we put this in a cabal.project file, not ~/.cabal/config, in order to avoid
diff --git a/src/HaskellCI/Tools.hs b/src/HaskellCI/Tools.hs
--- a/src/HaskellCI/Tools.hs
+++ b/src/HaskellCI/Tools.hs
@@ -55,7 +55,7 @@
 libraryModuleArgs :: C.Library -> [String]
 libraryModuleArgs l
     | null dirsOrMods = []
-    | otherwise       = exts ++ dirsOrMods
+    | otherwise       = lang ++ exts ++ dirsOrMods
   where
     bi = l ^. L.buildInfo
 
@@ -63,12 +63,14 @@
         | null (C.hsSourceDirs bi) = map C.prettyShow (C.exposedModules l)
         | otherwise                = map C.getSymbolicPath $ C.hsSourceDirs bi
 
+    lang = maybe [] (pure . ("-X" ++) . C.prettyShow) (C.defaultLanguage bi)
+
     exts = map (("-X" ++) . C.prettyShow) (C.defaultExtensions bi)
 
 executableModuleArgs :: C.Executable -> [String]
 executableModuleArgs e
     | null dirsOrMods = []
-    | otherwise       = exts ++ dirsOrMods
+    | otherwise       = lang ++ exts ++ dirsOrMods
   where
     bi = e ^. L.buildInfo
 
@@ -76,6 +78,8 @@
         -- note: we don't try to find main_is location, if hsSourceDirs is empty.
         | null (C.hsSourceDirs bi) = map C.prettyShow (C.otherModules bi)
         | otherwise                = map C.getSymbolicPath $ C.hsSourceDirs bi
+
+    lang = maybe [] (pure . ("-X" ++) . C.prettyShow) (C.defaultLanguage bi)
 
     exts = map (("-X" ++) . C.prettyShow) (C.defaultExtensions bi)
 
diff --git a/src/HaskellCI/Travis.hs b/src/HaskellCI/Travis.hs
--- a/src/HaskellCI/Travis.hs
+++ b/src/HaskellCI/Travis.hs
@@ -601,7 +601,7 @@
                 sh "echo 'package *' >> cabal.project"
                 sh "echo '  ghc-options: -Werror=missing-methods' >> cabal.project"
 
-        cat "cabal.project" $ lines $ C.showFields' (const []) (const id) 2 extraCabalProjectFields
+        cat "cabal.project" $ lines $ C.showFields' (const []) (const id) 2 $ extraCabalProjectFields ""
 
         -- If using head.hackage, allow building with newer versions of GHC boot libraries.
         -- Note that we put this in a cabal.project file, not ~/.cabal/config, in order to avoid