Ship transformers with GHC

This means that we can use the standard MonadIO class, rather than
needing our own copy.

compiler/ghc.cabal.in

@@ -52,7 +52,8 @@ Library
                    array      >= 0.1 && < 0.5,
                    filepath   >= 1   && < 1.4,
                    Cabal,
-                   hpc
+                   hpc,
+                   transformers
 
     if flag(stage1) && impl(ghc < 7.5)
         Build-Depends: old-time   >= 1   && < 1.2

compiler/utils/MonadUtils.hs

@@ -23,37 +23,16 @@ module MonadUtils
         , maybeMapM
         ) where
 
--------------------------------------------------------------------------------
--- Detection of available libraries
--------------------------------------------------------------------------------
-
--- we don't depend on MTL for now
-#define HAVE_MTL 0
-
 -------------------------------------------------------------------------------
 -- Imports
 -------------------------------------------------------------------------------
 
 import Maybes
 
 import Control.Applicative
-#if HAVE_MTL
-import Control.Monad.Trans
-#endif
 import Control.Monad
 import Control.Monad.Fix
-
--------------------------------------------------------------------------------
--- MTL
--------------------------------------------------------------------------------
-
-#if !HAVE_MTL
-
-class Monad m => MonadIO m where
-    liftIO :: IO a -> m a
-
-instance MonadIO IO where liftIO = id
-#endif
+import Control.Monad.IO.Class
 
 -------------------------------------------------------------------------------
 -- Lift combinators

ghc.mk

@@ -330,7 +330,7 @@ endif
 # They do not say "this package will be built"; see $(PACKAGES_xx) for that
 
 # Packages that are built but not installed
-PKGS_THAT_ARE_INTREE_ONLY := haskeline transformers terminfo xhtml
+PKGS_THAT_ARE_INTREE_ONLY := haskeline terminfo xhtml
 
 PKGS_THAT_ARE_DPH := \
     dph/dph-base \
@@ -355,7 +355,7 @@ PKGS_THAT_USE_TH := $(PKGS_THAT_ARE_DPH)
 #
 # We assume that the stage0 compiler has a suitable bytestring package,
 # so we don't have to include it below.
-PKGS_THAT_BUILD_WITH_STAGE0 = Cabal/Cabal hpc binary bin-package-db hoopl
+PKGS_THAT_BUILD_WITH_STAGE0 = Cabal/Cabal hpc binary bin-package-db hoopl transformers
 
 # $(EXTRA_PACKAGES)  is another classification, of packages built but
 #                    not installed
@@ -1337,17 +1337,17 @@ BINDIST_LIBRARY_FLAGS = --enable-library-vanilla --disable-shared
 endif
 BINDIST_LIBRARY_FLAGS += --disable-library-prof
 
-.PHONY: validate_build_transformers
-validate_build_transformers:
-	cd libraries/transformers && "$(BINDIST_PREFIX)/bin/ghc" --make Setup
-	cd libraries/transformers && ./Setup configure --with-ghc="$(BINDIST_PREFIX)/bin/ghc" $(BINDIST_HADDOCK_FLAG) $(BINDIST_LIBRARY_FLAGS) --global --builddir=dist-bindist --prefix="$(BINDIST_PREFIX)"
-	cd libraries/transformers && ./Setup build   --builddir=dist-bindist
+.PHONY: validate_build_xhtml
+validate_build_xhtml:
+	cd libraries/xhtml && "$(BINDIST_PREFIX)/bin/ghc" --make Setup
+	cd libraries/xhtml && ./Setup configure --with-ghc="$(BINDIST_PREFIX)/bin/ghc" $(BINDIST_HADDOCK_FLAG) $(BINDIST_LIBRARY_FLAGS) --global --builddir=dist-bindist --prefix="$(BINDIST_PREFIX)"
+	cd libraries/xhtml && ./Setup build   --builddir=dist-bindist
 ifeq "$(HADDOCK_DOCS)" "YES"
-	cd libraries/transformers && ./Setup haddock --builddir=dist-bindist
+	cd libraries/xhtml && ./Setup haddock --builddir=dist-bindist
 endif
-	cd libraries/transformers && ./Setup install --builddir=dist-bindist
-	cd libraries/transformers && ./Setup clean   --builddir=dist-bindist
-	cd libraries/transformers && rm -f Setup Setup.exe Setup.hi Setup.o
+	cd libraries/xhtml && ./Setup install --builddir=dist-bindist
+	cd libraries/xhtml && ./Setup clean   --builddir=dist-bindist
+	cd libraries/xhtml && rm -f Setup Setup.exe Setup.hi Setup.o
 
 # -----------------------------------------------------------------------------
 # Numbered phase targets

ghc/GhciMonad.hs

@@ -37,7 +37,6 @@ import SrcLoc
 import Module
 import ObjLink
 import Linker
-import qualified MonadUtils
 
 import Exception
 import Numeric
@@ -47,13 +46,13 @@ import Data.IORef
 import System.CPUTime
 import System.Environment
 import System.IO
-import Control.Monad as Monad
+import Control.Monad
 import GHC.Exts
 
 import System.Console.Haskeline (CompletionFunc, InputT)
 import qualified System.Console.Haskeline as Haskeline
-import Control.Monad.Trans.Class as Trans
-import Control.Monad.IO.Class as Trans
+import Control.Monad.Trans.Class
+import Control.Monad.IO.Class
 
 -----------------------------------------------------------------------------
 -- GHCi monad
@@ -186,11 +185,8 @@ modifyGHCiState f = GHCi $ \r -> liftIO $ readIORef r >>= writeIORef r . f
 liftGhc :: Ghc a -> GHCi a
 liftGhc m = GHCi $ \_ -> m
 
-instance MonadUtils.MonadIO GHCi where
-  liftIO = liftGhc . MonadUtils.liftIO
-
-instance Trans.MonadIO Ghc where
-  liftIO = MonadUtils.liftIO
+instance MonadIO GHCi where
+  liftIO = liftGhc . liftIO
 
 instance HasDynFlags GHCi where
   getDynFlags = getSessionDynFlags
@@ -206,9 +202,6 @@ instance GhcMonad (InputT GHCi) where
   setSession = lift . setSession
   getSession = lift getSession
 
-instance MonadUtils.MonadIO (InputT GHCi) where
-  liftIO = Trans.liftIO
-
 instance ExceptionMonad GHCi where
   gcatch m h = GHCi $ \r -> unGHCi m r `gcatch` (\e -> unGHCi (h e) r)
   gblock (GHCi m)   = GHCi $ \r -> gblock (m r)
@@ -220,9 +213,6 @@ instance ExceptionMonad GHCi where
                              in
                                 unGHCi (f g_restore) s
 
-instance MonadIO GHCi where
-  liftIO = MonadUtils.liftIO
-
 instance Haskeline.MonadException Ghc where
   controlIO f = Ghc $ \s -> Haskeline.controlIO $ \(Haskeline.RunIO run) -> let
                     run' = Haskeline.RunIO (fmap (Ghc . const) . run . flip unGhc s)
@@ -259,7 +249,7 @@ printForUser :: GhcMonad m => SDoc -> m ()
 printForUser doc = do
   unqual <- GHC.getPrintUnqual
   dflags <- getDynFlags
-  MonadUtils.liftIO $ Outputable.printForUser dflags stdout unqual doc
+  liftIO $ Outputable.printForUser dflags stdout unqual doc
 
 printForUserPartWay :: SDoc -> GHCi ()
 printForUserPartWay doc = do

mk/validate-settings.mk

@@ -113,6 +113,7 @@ libraries/mtl_dist-install_EXTRA_HC_OPTS += -Wwarn
 libraries/primitive_dist-install_EXTRA_HC_OPTS += -Wwarn
 
 # temporarily turn off -Werror for transformers
+libraries/transformers_dist-boot_EXTRA_HC_OPTS += -Wwarn
 libraries/transformers_dist-install_EXTRA_HC_OPTS += -Wwarn
 
 # vector has some unused match warnings

validate

@@ -106,16 +106,13 @@ if [ $speed != "FAST" ]; then
     $make test_bindist TEST_PREP=YES
 
     #
-    # Install the transformers package into the bindist, because it is
-    # used by some tests.
-    # It isn't essential that we do this (the failing tests will
-    # be treated as expected failures), but we get a bit more test
-    # coverage, and also verify that we can install a package into the
+    # Install the xhtml package into the bindist.
+    # This verifies that we can install a package into the
     # bindist with Cabal.
     #
     bindistdir="bindisttest/install   dir"
 
-    $make validate_build_transformers BINDIST_PREFIX="$thisdir/$bindistdir"
+    $make validate_build_xhtml BINDIST_PREFIX="$thisdir/$bindistdir"
 fi
 
 fi # testsuite-only