Separate the language flags from the other DynFlag's

[ghc-hetmet.git] / compiler / typecheck / TcPat.lhs

diff --git a/compiler/typecheck/TcPat.lhs b/compiler/typecheck/TcPat.lhs
index 23e6bbf..022796e 100644 (file)
--- a/compiler/typecheck/TcPat.lhs
+++ b/compiler/typecheck/TcPat.lhs
@@ -30,21 +30,19 @@ import VarSet
 import TcUnify
 import TcHsType
 import TysWiredIn
-import Type
 import Coercion
 import StaticFlags
 import TyCon
 import DataCon
 import PrelNames
 import BasicTypes hiding (SuccessFlag(..))
-import DynFlags        ( DynFlag( Opt_GADTs ) )
+import DynFlags
 import SrcLoc
 import ErrUtils
 import Util
-import Maybes
 import Outputable
 import FastString
-import Monad
+import Control.Monad
 \end{code}
 
 
@@ -181,7 +179,7 @@ tcPatBndr :: PatState -> Name -> BoxySigmaType -> TcM TcId
 tcPatBndr (PS { pat_ctxt = LetPat lookup_sig }) bndr_name pat_ty
   | Just mono_ty <- lookup_sig bndr_name
   = do { mono_name <- newLocalName bndr_name
-       ; boxyUnify mono_ty pat_ty
+       ; _ <- boxyUnify mono_ty pat_ty
        ; return (Id.mkLocalId mono_name mono_ty) }
 
   | otherwise
@@ -238,7 +236,7 @@ unBoxArgType ty pp_this
                return ty'
          else do       -- OpenTypeKind, so constrain it
        { ty2 <- newFlexiTyVarTy argTypeKind
-       ; unifyType ty' ty2
+       ; _ <- unifyType ty' ty2
        ; return ty' }}
   where
     msg = pp_this <+> ptext (sLit "cannot be bound to an unboxed tuple")
@@ -367,9 +365,13 @@ tc_pat pstate lpat@(LazyPat pat) pat_ty thing_inside
        -- Check no existentials
        ; unless (null pat_tvs) $ lazyPatErr lpat pat_tvs
 
+       -- Check there are no unlifted types under the lazy pattern
+       ; when (any (isUnLiftedType . idType) $ collectPatBinders pat') $
+               lazyUnliftedPatErr lpat
+
        -- Check that the pattern has a lifted type
        ; pat_tv <- newBoxyTyVar liftedTypeKind
-       ; boxyUnify pat_ty (mkTyVarTy pat_tv)
+       ; _ <- boxyUnify pat_ty (mkTyVarTy pat_tv)
 
        ; return (LazyPat pat', [], res) }
 
@@ -431,7 +433,11 @@ tc_pat pstate (SigPatIn pat sig_ty) pat_ty thing_inside
             failWithTc (badSigPat pat_ty)
        ; (pat', tvs, res) <- tcExtendTyVarEnv2 tv_binds $
                              tc_lpat pat inner_ty pstate thing_inside
-       ; return (SigPatOut pat' inner_ty, tvs, res) }
+        ; return (SigPatOut pat' inner_ty, tvs, res) }
+
+-- Use this when we add pattern coercions back in
+--       return (mkCoPatCoI (mkSymCoI coi) (SigPatOut pat' inner_ty) pat_ty
+--                 , tvs, res) }
 
 tc_pat _ pat@(TypePat _) _ _
   = failWithTc (badTypePat pat)
@@ -626,7 +632,7 @@ tcConPat pstate con_span data_con tycon pat_ty arg_pats thing_inside
                                                    unwrap_ty res_pat
 
          -- Add the stupid theta
-       ; addDataConStupidTheta data_con ctxt_res_tys
+       ; setSrcSpan con_span $ addDataConStupidTheta data_con ctxt_res_tys
 
        ; ex_tvs' <- tcInstSkolTyVars skol_info ex_tvs  
                      -- Get location from monad, not from ex_tvs
@@ -1039,6 +1045,12 @@ lazyPatErr _ tvs
     hang (ptext (sLit "A lazy (~) pattern cannot match existential or GADT data constructors"))
        2 (vcat (map pprSkolTvBinding tvs))
 
+lazyUnliftedPatErr :: OutputableBndr name => Pat name -> TcM ()
+lazyUnliftedPatErr pat
+  = failWithTc $
+    hang (ptext (sLit "A lazy (~) pattern cannot contain unlifted types"))
+       2 (ppr pat)
+
 nonRigidMatch :: PatCtxt -> DataCon -> SDoc
 nonRigidMatch ctxt con
   =  hang (ptext (sLit "GADT pattern match in non-rigid context for") <+> quotes (ppr con))