#include "HsVersions.h"
import HsSyn ( TyClDecl(..), HsConDetails(..), HsTyVarBndr(..),
- ConDecl(..), Sig(..), , NewOrData(..),
+ ConDecl(..), Sig(..), , NewOrData(..), ResType(..),
tyClDeclTyVars, isSynDecl,
LTyClDecl, tcdName, hsTyVarName, LHsTyVarBndr
)
import TcClassDcl ( tcClassSigs, tcAddDeclCtxt )
import TcHsType ( kcHsTyVars, kcHsLiftedSigType, kcHsType,
kcHsContext, tcTyVarBndrs, tcHsKindedType, tcHsKindedContext,
- kcHsSigType, tcHsBangType, tcLHsConSig, tcDataKindSig )
+ kcHsSigType, tcHsBangType, tcLHsConResTy, tcDataKindSig )
import TcMType ( newKindVar, checkValidTheta, checkValidType, checkFreeness,
UserTypeCtxt(..), SourceTyCtxt(..) )
import TcType ( TcKind, TcType, tyVarsOfType, mkPhiTy,
- mkArrowKind, liftedTypeKind, mkTyVarTys, tcEqTypes,
- tcSplitSigmaTy, tcEqType )
+ mkArrowKind, liftedTypeKind, mkTyVarTys,
+ tcSplitSigmaTy, tcEqTypes, tcGetTyVar_maybe )
import Type ( splitTyConApp_maybe, pprThetaArrow, pprParendType )
import Kind ( mkArrowKinds, splitKindFunTys )
import Generics ( validGenericMethodType, canDoGenerics )
tyConDataCons, mkForeignTyCon, isProductTyCon, isRecursiveTyCon,
tyConStupidTheta, getSynTyConDefn, isSynTyCon, tyConName )
import DataCon ( DataCon, dataConWrapId, dataConName, dataConSig,
- dataConFieldLabels, dataConOrigArgTys, dataConTyCon )
-import Type ( zipTopTvSubst, substTys )
+ dataConFieldLabels, dataConTyCon,
+ dataConTyVars, dataConFieldType, dataConResTys )
import Var ( TyVar, idType, idName )
-import VarSet ( elemVarSet )
+import VarSet ( elemVarSet, mkVarSet )
import Name ( Name )
import Outputable
+import Maybe ( isJust, fromJust )
+import Unify ( tcMatchTys, tcMatchTyX )
import Util ( zipLazy, isSingleton, notNull, sortLe )
import List ( partition )
import SrcLoc ( Located(..), unLoc, getLoc )
import ListSetOps ( equivClasses )
+import List ( delete )
import Digraph ( SCC(..) )
import DynFlags ( DynFlag( Opt_GlasgowExts, Opt_Generics,
Opt_UnboxStrictFields ) )
; cons' <- mappM (wrapLocM kc_con_decl) cons
; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdCons = cons'}) }
where
- kc_con_decl (ConDecl name ex_tvs ex_ctxt details)
- = kcHsTyVars ex_tvs $ \ ex_tvs' ->
- do { ex_ctxt' <- kcHsContext ex_ctxt
- ; details' <- kc_con_details details
- ; return (ConDecl name ex_tvs' ex_ctxt' details')}
- kc_con_decl (GadtDecl name ty)
- = do { ty' <- kcHsSigType ty
- ; traceTc (text "kc_con_decl" <+> ppr name <+> ppr ty')
- ; return (GadtDecl name ty') }
+ kc_con_decl (ConDecl name expl ex_tvs ex_ctxt details res) = do
+ kcHsTyVars ex_tvs $ \ex_tvs' -> do
+ ex_ctxt' <- kcHsContext ex_ctxt
+ details' <- kc_con_details details
+ res' <- case res of
+ ResTyH98 -> return ResTyH98
+ ResTyGADT ty -> return . ResTyGADT =<< kcHsSigType ty
+ return (ConDecl name expl ex_tvs' ex_ctxt' details' res')
kc_con_details (PrefixCon btys)
= do { btys' <- mappM kc_larg_ty btys ; return (PrefixCon btys') }
arg_vrcs = calc_vrcs tc_name
is_rec = calc_isrec tc_name
h98_syntax = case cons of -- All constructors have same shape
- L _ (GadtDecl {}) : _ -> False
+ L _ (ConDecl { con_res = ResTyGADT _ }) : _ -> False
other -> True
tcTyClDecl1 calc_vrcs calc_isrec
-> ConDecl Name -> TcM DataCon
tcConDecl unbox_strict NewType tycon tc_tvs -- Newtypes
- (ConDecl name ex_tvs ex_ctxt details)
+ (ConDecl name _ ex_tvs ex_ctxt details ResTyH98)
= ASSERT( null ex_tvs && null (unLoc ex_ctxt) )
do { let tc_datacon field_lbls arg_ty
= do { arg_ty' <- tcHsKindedType arg_ty -- No bang on newtype
PrefixCon [arg_ty] -> tc_datacon [] arg_ty
RecCon [(field_lbl, arg_ty)] -> tc_datacon [field_lbl] arg_ty }
-tcConDecl unbox_strict DataType tycon tc_tvs -- Ordinary data types
- (ConDecl name ex_tvs ex_ctxt details)
- = tcTyVarBndrs ex_tvs $ \ ex_tvs' -> do
- { ex_ctxt' <- tcHsKindedContext ex_ctxt
+tcConDecl unbox_strict DataType tycon tc_tvs -- Data types
+ (ConDecl name _ tvs ctxt details res_ty)
+ = tcTyVarBndrs tvs $ \ tvs' -> do
+ { ctxt' <- tcHsKindedContext ctxt
+ ; (data_tc, res_ty_args) <- tcResultType tycon tc_tvs res_ty
; let
- is_vanilla = null ex_tvs && null (unLoc ex_ctxt)
- -- Vanilla iff no ex_tvs and no context
- -- Must check the context too because of
- -- implicit params; e.g.
- -- data T = (?x::Int) => MkT Int
+ con_tvs = case res_ty of
+ ResTyH98 -> tc_tvs ++ tvs'
+ ResTyGADT _ -> tryVanilla tvs' res_ty_args
+
+ -- Vanilla iff result type matches the quantified vars exactly,
+ -- and there is no existential context
+ -- Must check the context too because of implicit params; e.g.
+ -- data T = (?x::Int) => MkT Int
+ is_vanilla = res_ty_args `tcEqTypes` mkTyVarTys con_tvs
+ && null (unLoc ctxt)
tc_datacon is_infix field_lbls btys
- = do { let { bangs = map getBangStrictness btys }
+ = do { let bangs = map getBangStrictness btys
; arg_tys <- mappM tcHsBangType btys
; buildDataCon (unLoc name) is_infix is_vanilla
(argStrictness unbox_strict tycon bangs arg_tys)
(map unLoc field_lbls)
- (tc_tvs ++ ex_tvs')
- ex_ctxt'
- arg_tys
- tycon (mkTyVarTys tc_tvs) }
+ con_tvs ctxt' arg_tys
+ data_tc res_ty_args }
+ -- NB: we put data_tc, the type constructor gotten from the constructor
+ -- type signature into the data constructor; that way
+ -- checkValidDataCon can complain if it's wrong.
+
; case details of
PrefixCon btys -> tc_datacon False [] btys
- InfixCon bty1 bty2 -> tc_datacon True [] [bty1,bty2]
- RecCon fields -> do { checkTc (null ex_tvs) (exRecConErr name)
- -- It's ok to have an implicit-parameter context
- -- for the data constructor, provided it binds
- -- no type variables
- ; let { (field_names, btys) = unzip fields }
- ; tc_datacon False field_names btys } }
-
-tcConDecl unbox_strict DataType tycon tc_tvs -- GADTs
- decl@(GadtDecl name con_ty)
- = do { traceTc (text "tcConDecl" <+> ppr name)
- ; (tvs, theta, bangs, arg_tys, data_tc, res_tys) <- tcLHsConSig con_ty
-
- ; traceTc (text "tcConDecl1" <+> ppr name)
- ; let -- Now dis-assemble the type, and check its form
- is_vanilla = null theta && mkTyVarTys tvs `tcEqTypes` res_tys
-
- -- Vanilla datacons guarantee to use the same
- -- type variables as the parent tycon
- (tvs', arg_tys', res_tys')
- | is_vanilla = (tc_tvs, substTys subst arg_tys, substTys subst res_tys)
- | otherwise = (tvs, arg_tys, res_tys)
- subst = zipTopTvSubst tvs (mkTyVarTys tc_tvs)
-
- ; traceTc (text "tcConDecl3" <+> ppr name)
- ; buildDataCon (unLoc name) False {- Not infix -} is_vanilla
- (argStrictness unbox_strict tycon bangs arg_tys)
- [{- No field labels -}]
- tvs' theta arg_tys' data_tc res_tys' }
- -- NB: we put data_tc, the type constructor gotten from the constructor
- -- type signature into the data constructor; that way checkValidDataCon
- -- can complain if it's wrong.
+ InfixCon bty1 bty2 -> tc_datacon True [] [bty1,bty2]
+ RecCon fields -> tc_datacon False field_names btys
+ where
+ (field_names, btys) = unzip fields
+
+ }
+
+tcResultType :: TyCon -> [TyVar] -> ResType Name -> TcM (TyCon, [TcType])
+tcResultType tycon tvs ResTyH98 = return (tycon, mkTyVarTys tvs)
+tcResultType _ _ (ResTyGADT res_ty) = tcLHsConResTy res_ty
+
+tryVanilla :: [TyVar] -> [TcType] -> [TyVar]
+-- (tryVanilla tvs tys) returns a permutation of tvs.
+-- It tries to re-order the tvs so that it exactly
+-- matches the [Type], if that is possible
+tryVanilla tvs (ty:tys) | Just tv <- tcGetTyVar_maybe ty -- The type is a tyvar
+ , tv `elem` tvs -- That tyvar is in the list
+ = tv : tryVanilla (delete tv tvs) tys
+tryVanilla tvs tys = tvs -- Fall through case
+
-------------------
argStrictness :: Bool -- True <=> -funbox-strict_fields
}
-------------------------
+-- For data types declared with record syntax, we require
+-- that each constructor that has a field 'f'
+-- (a) has the same result type
+-- (b) has the same type for 'f'
+-- module alpha conversion of the quantified type variables
+-- of the constructor.
+
checkValidTyCon :: TyCon -> TcM ()
checkValidTyCon tc
| isSynTyCon tc
groups = equivClasses cmp_fld (concatMap get_fields data_cons)
cmp_fld (f1,_) (f2,_) = f1 `compare` f2
- get_fields con = dataConFieldLabels con `zip` dataConOrigArgTys con
+ get_fields con = dataConFieldLabels con `zip` repeat con
-- dataConFieldLabels may return the empty list, which is fine
- check_fields fields@((first_field_label, field_ty) : other_fields)
+ -- XXX - autrijus - Make this far more complex to acommodate
+ -- for different return types. Add res_ty to the mix,
+ -- comparing them in two steps, all for good error messages.
+ -- Plan: Use Unify.tcMatchTys to compare the first candidate's
+ -- result type against other candidates' types (check bothways).
+ -- If they magically agrees, take the substitution and
+ -- apply them to the latter ones, and see if they match perfectly.
+ -- check_fields fields@((first_field_label, field_ty) : other_fields)
+ check_fields fields@((label, con1) : other_fields)
-- These fields all have the same name, but are from
-- different constructors in the data type
- = -- Check that all the fields in the group have the same type
+ = recoverM (return ()) $ mapM_ checkOne other_fields
+ -- Check that all the fields in the group have the same type
-- NB: this check assumes that all the constructors of a given
-- data type use the same type variables
- checkTc (all (tcEqType field_ty . snd) other_fields)
- (fieldTypeMisMatch first_field_label)
+ where
+ tvs1 = mkVarSet (dataConTyVars con1)
+ res1 = dataConResTys con1
+ fty1 = dataConFieldType con1 label
+
+ checkOne (_, con2) -- Do it bothways to ensure they are structurally identical
+ = do { checkFieldCompat label con1 con2 tvs1 res1 res2 fty1 fty2
+ ; checkFieldCompat label con2 con1 tvs2 res2 res1 fty2 fty1 }
+ where
+ tvs2 = mkVarSet (dataConTyVars con2)
+ res2 = dataConResTys con2
+ fty2 = dataConFieldType con2 label
+
+checkFieldCompat fld con1 con2 tvs1 res1 res2 fty1 fty2
+ = do { checkTc (isJust mb_subst1) (resultTypeMisMatch fld con1 con2)
+ ; checkTc (isJust mb_subst2) (fieldTypeMisMatch fld con1 con2) }
+ where
+ mb_subst1 = tcMatchTys tvs1 res1 res2
+ mb_subst2 = tcMatchTyX tvs1 (fromJust mb_subst1) fty1 fty2
-------------------------------
checkValidDataCon :: TyCon -> DataCon -> TcM ()
---------------------------------------------------------------------
-fieldTypeMisMatch field_name
- = sep [ptext SLIT("Different constructors give different types for field"), quotes (ppr field_name)]
+resultTypeMisMatch field_name con1 con2
+ = vcat [sep [ptext SLIT("Constructors") <+> ppr con1 <+> ptext SLIT("and") <+> ppr con2,
+ ptext SLIT("have a common field") <+> quotes (ppr field_name) <> comma],
+ nest 2 $ ptext SLIT("but have different result types")]
+fieldTypeMisMatch field_name con1 con2
+ = sep [ptext SLIT("Constructors") <+> ppr con1 <+> ptext SLIT("and") <+> ppr con2,
+ ptext SLIT("give different types for field"), quotes (ppr field_name)]
dataConCtxt con = sep [ptext SLIT("When checking the data constructor:"),
nest 2 (ex_part <+> pprThetaArrow ex_theta <+> ppr con <+> arg_part)]
where
le (L l1 _) (L l2 _) = l1 <= l2
-exRecConErr name
- = ptext SLIT("Can't combine named fields with locally-quantified type variables or context")
- $$
- (ptext SLIT("In the declaration of data constructor") <+> ppr name)
-
badDataConTyCon data_con
= hang (ptext SLIT("Data constructor") <+> quotes (ppr data_con) <+>
ptext SLIT("returns type") <+> quotes (ppr (dataConTyCon data_con)))
projects / ghc-hetmet.git / blobdiff