[project @ 2001-03-23 17:34:44 by simonmar]

[ghc-hetmet.git] / ghc / compiler / deSugar / Check.lhs

diff --git a/ghc/compiler/deSugar/Check.lhs b/ghc/compiler/deSugar/Check.lhs
index 45a1ad8..dd4c9ae 100644 (file)
--- a/ghc/compiler/deSugar/Check.lhs
+++ b/ghc/compiler/deSugar/Check.lhs
@@ -13,25 +13,17 @@ module Check ( check , ExhaustivePat ) where
 import HsSyn           
 import TcHsSyn         ( TypecheckedPat )
 import DsHsSyn         ( outPatType ) 
-import CoreSyn         
-
-import DsUtils         ( EquationInfo(..),
-                         MatchResult(..),
-                         EqnSet,
-                         CanItFail(..),
-                         tidyLitPat
+import DsUtils         ( EquationInfo(..), MatchResult(..), EqnSet, 
+                         CanItFail(..),  tidyLitPat, tidyNPat, 
                        )
 import Id              ( idType )
 import DataCon         ( DataCon, dataConTyCon, dataConArgTys,
                          dataConSourceArity, dataConFieldLabels )
-import Name             ( Name, mkLocalName, getOccName, isDataSymOcc, getName, mkSrcVarOcc )
-import Type            ( Type, splitAlgTyConApp, mkTyVarTys,
-                          splitTyConApp_maybe
-                       )
-import TysWiredIn      ( nilDataCon, consDataCon, 
-                          mkListTy, mkTupleTy, tupleCon
-                       )
-import Unique          ( unboundKey )
+import Name             ( Name, mkLocalName, getOccName, isDataSymOcc, getName, mkVarOcc )
+import Type            ( splitAlgTyConApp, mkTyVarTys, splitTyConApp_maybe )
+import TysPrim         ( charPrimTy )
+import TysWiredIn
+import PrelNames       ( unboundKey )
 import TyCon            ( tyConDataCons, tupleTyConBoxity, isTupleTyCon )
 import BasicTypes      ( Boxity(..) )
 import SrcLoc          ( noSrcLoc )
@@ -151,13 +143,7 @@ untidy b (ConOpPatIn pat1 name fixity pat2) =
 untidy _ (ListPatIn pats)  = ListPatIn (map untidy_no_pars pats) 
 untidy _ (TuplePatIn pats boxed) = TuplePatIn (map untidy_no_pars pats) boxed
 
-untidy _ (SigPatIn pat ty)      = panic "Check.untidy: SigPatIn"
-untidy _ (LazyPatIn pat)        = panic "Check.untidy: LazyPatIn"
-untidy _ (AsPatIn name pat)     = panic "Check.untidy: AsPatIn"
-untidy _ (NPlusKPatIn name lit) = panic "Check.untidy: NPlusKPatIn"
-untidy _ (NegPatIn ipat)        = panic "Check.untidy: NegPatIn"
-untidy _ (ParPatIn pat)         = panic "Check.untidy: ParPatIn"
-untidy _ (RecPatIn name fields) = panic "Check.untidy: RecPatIn"
+untidy _ pat = pprPanic "Check.untidy: SigPatIn" (ppr pat)
 
 pars :: NeedPars -> WarningPat -> WarningPat
 pars True p = ParPatIn p
@@ -386,7 +372,7 @@ make_row_vars used_lits (EqnInfo _ _ pats _ ) =
   where new_var = hash_x
 
 hash_x = mkLocalName unboundKey {- doesn't matter much -}
-                    (mkSrcVarOcc SLIT("#x"))
+                    (mkVarOcc SLIT("#x"))
                     noSrcLoc
 
 make_row_vars_for_constructor :: EquationInfo -> [WarningPat]
@@ -427,12 +413,16 @@ get_unused_cons :: [TypecheckedPat] -> [DataCon]
 get_unused_cons used_cons = unused_cons
      where
        (ConPat _ ty _ _ _) = head used_cons
-       Just (ty_con,_)            = splitTyConApp_maybe ty
+       Just (ty_con,_)            = sTyConApp_maybe used_cons ty
        all_cons                   = tyConDataCons ty_con
        used_cons_as_id            = map (\ (ConPat d _ _ _ _) -> d) used_cons
        unused_cons                = uniqSetToList
                 (mkUniqSet all_cons `minusUniqSet` mkUniqSet used_cons_as_id) 
 
+sTyConApp_maybe used_cons ty =
+    case splitTyConApp_maybe ty of
+    Just x -> Just x
+    Nothing -> pprTrace "splitTyConApp_maybe" (ppr (used_cons, ty)) $ Nothing
 
 all_vars :: [TypecheckedPat] -> Bool
 all_vars []              = True
@@ -625,8 +615,18 @@ simplify_pat (RecPat dc ty ex_tvs dicts idps)
       | nm == n    = (nm,p):xs
       | otherwise  = x : insertNm nm p xs
 
-simplify_pat pat@(LitPat lit lit_ty)        = tidyLitPat lit lit_ty pat
-simplify_pat pat@(NPat   lit lit_ty hsexpr) = tidyLitPat lit lit_ty pat
+simplify_pat pat@(LitPat lit lit_ty)        = tidyLitPat lit pat
+
+-- unpack string patterns fully, so we can see when they overlap with
+-- each other, or even explicit lists of Chars.
+simplify_pat pat@(NPat (HsString s) _ _) = 
+   foldr (\c pat -> ConPat consDataCon stringTy [] [] [mk_char_lit c,pat])
+       (ConPat nilDataCon stringTy [] [] []) (_UNPK_INT_ s)
+  where
+    mk_char_lit c = ConPat charDataCon charTy [] [] 
+                       [LitPat (HsCharPrim c) charPrimTy]
+
+simplify_pat pat@(NPat lit lit_ty hsexpr) = tidyNPat lit lit_ty pat
 
 simplify_pat (NPlusKPat        id hslit ty hsexpr1 hsexpr2) = 
      WildPat ty