diff --git a/Makefile.am b/Makefile.am
index fe5c456..2de55b4 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -6,12 +6,29 @@ GHC_OPTS = \
 	-fwarn-missing-fields \
 	-fwarn-missing-methods \
 	-fwarn-missing-signatures \
+	-fwarn-monomorphism-restriction \
 	-fwarn-overlapping-patterns \
 	-fwarn-simple-patterns \
+	-fwarn-tabs \
 	-fwarn-type-defaults \
 	-fwarn-unused-binds \
 	-fwarn-unused-imports \
 	\
+	-XDeriveDataTypeable \
+	-XExistentialQuantification \
+	-XFlexibleContexts \
+	-XFlexibleInstances \
+	-XFunctionalDependencies \
+	-XGeneralizedNewtypeDeriving \
+	-XImpredicativeTypes \
+	-XKindSignatures \
+	-XMultiParamTypeClasses \
+	-XRank2Types \
+	-XScopedTypeVariables \
+	-XTypeOperators \
+	-XTypeSynonymInstances \
+	-XUndecidableInstances \
+	\
 	-hide-all-packages \
 	-package array \
 	-package @LIB_VER_base@ \
@@ -40,40 +57,6 @@ GHC_OPTS = \
 	-ipregen \
 	-itransformations
 
-if GHC68
-# I'd like to spell out all the flags for GHC 6.8 as follows.
-# But it seems that on GHC 6.8.2 (i386), this causes a GHC panic,
-# which I believe is related to the use of unsafeCoerce#.  So if anyone
-# else tries to do this in future, make sure to test on GHC 6.8.2 (which
-# is currently the latest version on Ubuntu and Gentoo)
-#
-# Addendum: I tried again once unsafeCoerce# was removed, but now it seems
-# that -Werror is being secretly activated, which is possibly due to
-# the GHC bug we had trouble with before (only fixed in 6.10 I think).
-
-#GHC_OPTS += -XDeriveDataTypeable
-#GHC_OPTS += -XExistentialQuantification
-#GHC_OPTS += -XFlexibleContexts
-#GHC_OPTS += -XFlexibleInstances
-#GHC_OPTS += -XFunctionalDependencies
-#GHC_OPTS += -XMultiParamTypeClasses
-#GHC_OPTS += -XRank2Types
-#GHC_OPTS += -XScopedTypeVariables
-#GHC_OPTS += -XTypeSynonymInstances
-
-GHC_OPTS += -XUndecidableInstances
-GHC_OPTS += -fwarn-tabs -fwarn-monomorphism-restriction
-else
-# GHC 6.7 or earlier.
-GHC_OPTS += -fallow-undecidable-instances
-endif
-
-if GHC610
-GHC_OPTS += -XImpredicativeTypes
-endif
-
-GHC_OPTS += -fglasgow-exts
-
 tock$(EXEEXT): $(BUILT_SOURCES) $(tock_SOURCES) $(config_sources)
 	@MKDIR_P@ obj
 	ghc $(GHC_OPTS) -o tock$(EXEEXT) --make Main -odir obj -hidir obj
@@ -102,28 +85,19 @@ GenTagAST$(EXEEXT): $(GenTagAST_SOURCES)
 
 # Both these results are near-identical.  The -g flag to alex tells it to generate
 # a lexer optimised for GHC.  The other part of the rule inserts the
-# -fno-warn-tabs flag under GHC >= 6.8, but doesn't add anything under previous
-# versions of GHC
+# -fno-warn-tabs flag.
 
 frontends/LexOccam.hs: frontends/LexOccam.x
 	alex -g frontends/LexOccam.x -o frontends/LexOccam.temphs
-if GHC68
 	echo "{-# OPTIONS_GHC -fno-warn-tabs -fno-warn-monomorphism-restriction #-}" > frontends/LexOccam.hs
 	cat frontends/LexOccam.temphs >> frontends/LexOccam.hs
 	rm frontends/LexOccam.temphs
-else
-	mv frontends/LexOccam.temphs frontends/LexOccam.hs
-endif
 
 frontends/LexRain.hs: frontends/LexRain.x
 	alex -g frontends/LexRain.x -o frontends/LexRain.temphs
-if GHC68
 	echo "{-# OPTIONS_GHC -fno-warn-tabs -fno-warn-monomorphism-restriction #-}" > frontends/LexRain.hs
 	cat frontends/LexRain.temphs >> frontends/LexRain.hs
 	rm frontends/LexRain.temphs
-else
-	mv frontends/LexRain.temphs frontends/LexRain.hs
-endif
 
 TOCKDIR=$(DATADIR)/tock
 TOCKMODDIR=$(TOCKDIR)/modules
diff --git a/common/ShowCode.hs b/common/ShowCode.hs
index c6faa58..7df6d06 100644
--- a/common/ShowCode.hs
+++ b/common/ShowCode.hs
@@ -1,4 +1,4 @@
-{-# OPTIONS_GHC -fallow-incoherent-instances #-}
+{-# LANGUAGE IncoherentInstances #-}
 {-
 Tock: a compiler for parallel languages
 Copyright (C) 2007, 2008, 2009  University of Kent
diff --git a/configure.ac b/configure.ac
index 6a0b0a5..3f2c18a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -82,14 +82,11 @@ AC_NEED_HASKELL_LIB([regex-posix],LIB_regexposix)
 ghc_version=`ghc --numeric-version | awk -F . '{printf "%d%03d%03d\n", $1, $2, $3}'`
 
 AC_MSG_CHECKING([whether GHC version is reasonable])
-if test $ghc_version -lt 6006000; then
-	AC_MSG_ERROR([GHC 6.6 or later is required])
+if test $ghc_version -lt 6012000; then
+	AC_MSG_ERROR([GHC 6.12 or later is required])
 fi
 AC_MSG_RESULT([OK])
 
-AM_CONDITIONAL([GHC68],[test $ghc_version -ge 6008000])
-AM_CONDITIONAL([GHC610],[test $ghc_version -ge 6010000])
-
 AC_DEFUN([AC_PICK_HASKELL_LIB_VER],
 [
   AC_MSG_CHECKING([for $1 library, major version $2])
@@ -101,16 +98,8 @@ AC_DEFUN([AC_PICK_HASKELL_LIB_VER],
   fi
 ])
 
-#GHC 6.10 and later have base-3 and base-4.  For now, we're sticking with
-#base-3, but we need to know the exact version to tell GHC.  We filter
-#for base-3, and take the last one (since ghc-pkg lists them in ascending order)
-if test $ghc_version -lt 6010000; then
-  AC_PICK_HASKELL_LIB_VER([base],[3],[LIB_VER_base])
-  LIB_VER_syb="$LIB_VER_base"
-else
-  AC_PICK_HASKELL_LIB_VER([base],[4],[LIB_VER_base])
-  AC_PICK_HASKELL_LIB_VER([syb],[0],LIB_VER_syb)
-fi
+AC_PICK_HASKELL_LIB_VER([base],[4],[LIB_VER_base])
+AC_PICK_HASKELL_LIB_VER([syb],[0],LIB_VER_syb)
 
 PKG_CHECK_MODULES(CCSP, ccsp-1.6 >= 1.6.3,,
 	AC_MSG_WARN([CCSP not located using pkg-config; you will not be able to compile output from the C backend on this machine: ] $CCSP_PKG_ERRORS)
diff --git a/pregen/GenNavAST.hs b/pregen/GenNavAST.hs
index 08b0e94..d91b187 100644
--- a/pregen/GenNavAST.hs
+++ b/pregen/GenNavAST.hs
@@ -59,7 +59,8 @@ main = do
          = (reverse . takeWhile (/= '/') . drop 3 . reverse) $ moduleFileName
     
     header isSpine moduleName =
-      ["{-# OPTIONS_GHC -fallow-overlapping-instances -fwarn-overlapping-patterns -fwarn-unused-matches -fwarn-unused-binds #-}"
+      ["{-# LANGUAGE OverlappingInstances #-}"
+      ,"{-# OPTIONS_GHC -fwarn-overlapping-patterns -fwarn-unused-matches -fwarn-unused-binds #-}"
       ,"-- | This module is auto-generated by Polyplate.  DO NOT EDIT."
       ,"module " ++ moduleName ++ " () where"
       ,""