tcdTyVars :: [LHsTyVarBndr name], -- Type variables
tcdTyPats :: Maybe [LHsType name], -- Type patterns
tcdKindSig:: Maybe Kind, -- Optional kind sig;
- -- (only for the 'where' form)
+ -- (only for the
+ -- 'where' form and
+ -- indexed type sigs)
tcdCons :: [LConDecl name], -- Data constructors
-- For data T a = T1 | T2 a the LConDecls all have ResTyH98
| TyFunction {tcdLName :: Located name, -- type constructor
tcdTyVars :: [LHsTyVarBndr name], -- type variables
tcdIso :: Bool, -- injective type?
- tcdKindSig:: Maybe Kind -- result kind
+ tcdKind :: Kind -- result kind
}
| TySynonym { tcdLName :: Located name, -- type constructor
= hsep [ptext SLIT("foreign import type dotnet"), ppr ltycon]
ppr (TyFunction {tcdLName = ltycon, tcdTyVars = tyvars, tcdIso = iso,
- tcdKindSig = mb_sig})
+ tcdKind = kind})
= typeMaybeIso <+> pp_decl_head [] ltycon tyvars Nothing <+>
- ppr_sig mb_sig
+ dcolon <+> pprKind kind
where
typeMaybeIso = if iso
then ptext SLIT("type iso")
else ptext SLIT("type")
- ppr_sig Nothing = empty
- ppr_sig (Just kind) = dcolon <+> pprKind kind
-
ppr (TySynonym {tcdLName = ltycon, tcdTyVars = tyvars, tcdTyPats = typats,
tcdSynRhs = mono_ty})
= hang (ptext SLIT("type") <+> pp_decl_head [] ltycon tyvars typats <+>
topdecl :: { OrdList (LHsDecl RdrName) }
: cl_decl { unitOL (L1 (TyClD (unLoc $1))) }
- | ty_decl {% checkTopTyClD $1 >>= return.unitOL.L1 }
+ | ty_decl {% checkTopTypeD $1 >>=
+ return.unitOL.L1 }
| 'instance' inst_type where
{ let (binds, sigs, ats) = cvBindsAndSigs (unLoc $3)
in unitOL (L (comb3 $1 $2 $3)
ty_decl :: { LTyClDecl RdrName }
-- type function signature and equations (w/ type synonyms as special
-- case); we need to handle all this in one rule to avoid a large
- -- number of shift/reduce conflicts (due to the generality of `type')
+ -- number of shift/reduce conflicts
: 'type' opt_iso type kind_or_ctype
--
-- Note the use of type for the head; this allows
; return (L (comb3 $1 $3 kind)
(TyFunction tc tvs $2 (unLoc kind)))
}
- Right ty ->
+ Right ty | not $2 ->
do { (tc, tvs, typats) <- checkSynHdr $3 True
; return (L (comb2 $1 ty)
(TySynonym tc tvs typats ty)) }
+ Right ty | otherwise ->
+ parseError (comb2 $1 ty)
+ "iso tag is only allowed in kind signatures"
}
+ -- kind signature of indexed type
+ | data_or_newtype tycl_hdr '::' kind
+ {% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
+ ; checkTyVars tparms False -- no type pattern
+ ; return $
+ L (comb3 $1 $2 $4)
+ (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing)
+ (Just (unLoc $4)) [] Nothing) } }
+
-- data type or newtype declaration
| data_or_newtype tycl_hdr constrs deriving
{% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
- ; tpats <- checkTyVars tparms True -- can have type pats
+ ; tpats <- checkTyVars tparms True -- can have type pats
; return $
L (comb4 $1 $2 $3 $4)
-- We need the location on tycl_hdr in case
: { False }
| 'iso' { True }
-kind_or_ctype :: { Either (Located (Maybe Kind)) (LHsType RdrName) }
- : { Left (noLoc Nothing) }
- | '::' kind { Left (LL (Just (unLoc $2))) }
- | '=' ctype { Right (LL (unLoc $2)) }
+kind_or_ctype :: { Either (Located Kind) (LHsType RdrName) }
+ : '::' kind { Left (LL (unLoc $2)) }
+ | '=' ctype { Right (LL (unLoc $2)) }
-- Note ctype, not sigtype, on the right of '='
-- We allow an explicit for-all but we don't insert one
-- in type Foo a = (b,b)
checkTyClHdr, -- LHsContext RdrName -> LHsType RdrName -> P (LHsContext RdrName, Located RdrName, [LHsTyVarBndr RdrName], [LHsType RdrName])
checkTyVars, -- [LHsType RdrName] -> Bool -> P ()
checkSynHdr, -- LHsType RdrName -> P (Located RdrName, [LHsTyVarBndr RdrName], Maybe [LHsType RdrName])
- checkTopTyClD, -- LTyClDecl RdrName -> P (HsDecl RdrName)
+ checkTopTypeD, -- LTyClDecl RdrName -> P (HsDecl RdrName)
checkInstType, -- HsType -> P HsType
checkPattern, -- HsExp -> P HsPat
checkPatterns, -- SrcLoc -> [HsExp] -> P [HsPat]
-- result. Eg, for
-- T Int [a]
-- we return
--- ('()', 'T', ['a'], Just ['Int', '[a]'])
+-- ('()', 'T', ['a'], ['Int', '[a]'])
checkTyClHdr (L l cxt) ty
= do (tc, tvs, parms) <- gol ty []
mapM_ chk_pred cxt
tvs' <- collects tvs ts
collect tvs' t
--- Wrap a toplevel type or class declaration into 'TyClDecl' after ensuring
--- that all type parameters are variables only (which is in contrast to
--- associated type declarations).
+-- Wrap a toplevel type or data declaration into 'TyClD' and ensure for
+-- data declarations that all type parameters are variables only (which is in
+-- contrast to type functions and associated type declarations).
--
-checkTopTyClD :: LTyClDecl RdrName -> P (HsDecl RdrName)
-checkTopTyClD (L _ d@TyData {tcdTyPats = Just typats}) =
+checkTopTypeD :: LTyClDecl RdrName -> P (HsDecl RdrName)
+checkTopTypeD (L _ d@TyData {tcdTyPats = Just typats}) =
do
+ -- `tcdTyPats' will only be of the form `Just typats' if `typats' contains
+ -- a non-variable pattern. We call `checkTyPats' instead of raising an
+ -- error straight away, as `checkTyPats' raises the error at the location
+ -- of that non-variable pattern.
+ --
checkTyVars typats False
- return $ TyClD d {tcdTyPats = Nothing}
-checkTopTyClD (L _ d) = return $ TyClD d
+ panic "checkTopTypeD: check on previous line should fail w/ a parse error"
+checkTopTypeD (L _ d) = return $ TyClD d
checkContext :: LHsType RdrName -> P (LHsContext RdrName)
checkContext (L l t)