set Opt_SpecConstr just in case.

Language/Haskell/GhcMod/DynFlags.hs

@@ -1,16 +1,14 @@
 module Language.Haskell.GhcMod.DynFlags where
 
-import qualified Language.Haskell.GhcMod.Gap as Gap
-import Language.Haskell.GhcMod.Types
-
 import Control.Applicative ((<$>))
 import Control.Monad (forM, void, (>=>))
+import DynFlags (ExtensionFlag(..), xopt, GeneralFlag(..), gopt_unset)
 import GHC (DynFlags(..), GhcMode(..), GhcLink(..), HscTarget(..), LoadHowMuch(..))
 import qualified GHC as G
-import GhcMonad
 import GHC.Paths (libdir)
-import DynFlags (ExtensionFlag(..), xopt)
-
+import GhcMonad
+import qualified Language.Haskell.GhcMod.Gap as Gap
+import Language.Haskell.GhcMod.Types
 import System.IO.Unsafe (unsafePerformIO)
 
 data Build = CabalPkg | SingleFile deriving Eq
@@ -42,6 +40,9 @@ setModeIntelligent df = df {
   , optLevel  = 0
   }
 
+setFlags :: DynFlags -> DynFlags
+setFlags df = df `gopt_unset` Opt_SpecConstr -- consume memory if -O2
+
 setIncludeDirs :: [IncludeDir] -> DynFlags -> DynFlags
 setIncludeDirs idirs df = df { importPaths = idirs }
 

Language/Haskell/GhcMod/Monad.hs

@@ -190,6 +190,7 @@ initSession build Options {..} CompilerOptions {..} = do
     df <- G.getSessionDynFlags
     void $ G.setSessionDynFlags =<< addCmdOpts ghcOptions
       ( setModeSimple
+      $ setFlags
       $ setIncludeDirs includeDirs
       $ setBuildEnv build
       $ setEmptyLogger