import ListSetOps
import Digraph
import DynFlags
+import FastString
import Data.List
import Control.Monad ( mplus )
tcTyAndClassDecls :: ModDetails -> [LTyClDecl Name]
-> TcM TcGblEnv -- Input env extended by types and classes
-- and their implicit Ids,DataCons
+-- Fails if there are any errors
+
tcTyAndClassDecls boot_details allDecls
- = do { -- Omit instances of type families; they are handled together
+ = checkNoErrs $ -- The code recovers internally, but if anything gave rise to
+ -- an error we'd better stop now, to avoid a cascade
+ do { -- Omit instances of type families; they are handled together
-- with the *heads* of class instances
; let decls = filter (not . isFamInstDecl . unLoc) allDecls
; tcExtendGlobalEnv syn_tycons $ do
-- Type-check the data types and classes
- { alg_tyclss <- mappM tc_decl kc_alg_decls
+ { alg_tyclss <- mapM tc_decl kc_alg_decls
; return (syn_tycons, concat alg_tyclss)
}}})
-- Finished with knot-tying now
-- Perform the validity check
{ traceTc (text "ready for validity check")
- ; mappM_ (addLocM checkValidTyCl) decls
+ ; mapM_ (addLocM checkValidTyCl) decls
; traceTc (text "done")
-- Add the implicit things;
tcFamInstDecl :: LTyClDecl Name -> TcM (Maybe TyThing) -- Nothing if error
tcFamInstDecl (L loc decl)
= -- Prime error recovery, set source location
- recoverM (returnM Nothing) $
+ recoverM (return Nothing) $
setSrcSpan loc $
tcAddDeclCtxt decl $
do { -- type families require -XTypeFamilies and can't be in an
-- (2) type check type equation
; tcTyVarBndrs k_tvs $ \t_tvs -> do { -- turn kinded into proper tyvars
- ; t_typats <- mappM tcHsKindedType k_typats
+ ; t_typats <- mapM tcHsKindedType k_typats
; t_rhs <- tcHsKindedType k_rhs
-- (3) check that
; unbox_strict <- doptM Opt_UnboxStrictFields
-- kind check the type indexes and the context
- ; t_typats <- mappM tcHsKindedType k_typats
+ ; t_typats <- mapM tcHsKindedType k_typats
; stupid_theta <- tcHsKindedContext k_ctxt
-- (3) Check that
-- - left-hand side contains no type family applications
-- (vanilla synonyms are fine, though, and we checked for
-- foralls earlier)
- ; mappM_ checkTyFamFreeness t_typats
+ ; mapM_ checkTyFamFreeness t_typats
-- - we don't use GADT syntax for indexed types
; checkTc h98_syntax (badGadtIdxTyDecl tc_name)
-- (4) construct representation tycon
; rep_tc_name <- newFamInstTyConName tc_name loc
+ ; let ex_ok = True -- Existentials ok for type families!
; tycon <- fixM (\ tycon -> do
- { data_cons <- mappM (addLocM (tcConDecl unbox_strict tycon t_tvs))
+ { data_cons <- mapM (addLocM (tcConDecl unbox_strict ex_ok tycon t_tvs))
k_cons
; tc_rhs <-
case new_or_data of
-- type functions can have a higher-kinded result
; let resultKind = mkArrowKinds (drop (length hs_typats) kinds) resKind
- ; typats <- TcRnMonad.zipWithM kcCheckHsType hs_typats kinds
+ ; typats <- zipWithM kcCheckHsType hs_typats kinds
; thing_inside tvs typats resultKind family
}
where
= do { -- First extend the kind env with each data type, class, and
-- indexed type, mapping them to a type variable
let initialKindDecls = concat [allDecls decl | L _ decl <- alg_decls]
- ; alg_kinds <- mappM getInitialKind initialKindDecls
+ ; alg_kinds <- mapM getInitialKind initialKindDecls
; tcExtendKindEnv alg_kinds $ do
-- Now kind-check the type synonyms, in dependency order
-- returning kind-annotated decls; we don't kind-check
-- instances of indexed types yet, but leave this to
-- `tcInstDecls1'
- { kc_alg_decls <- mappM (wrapLocM kcTyClDecl)
+ { kc_alg_decls <- mapM (wrapLocM kcTyClDecl)
(filter (not . isFamInstDecl . unLoc) alg_decls)
; return (kc_syn_decls, kc_alg_decls) }}}
= kcTyClDeclBody decl $ \ tvs' ->
do { is_boot <- tcIsHsBoot
; ctxt' <- kcHsContext ctxt
- ; ats' <- mappM (wrapLocM (kcFamilyDecl tvs')) ats
- ; sigs' <- mappM (wrapLocM kc_sig) sigs
+ ; ats' <- mapM (wrapLocM (kcFamilyDecl tvs')) ats
+ ; sigs' <- mapM (wrapLocM kc_sig) sigs
; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdSigs = sigs',
tcdATs = ats'}) }
where
kcDataDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdCons = cons})
tvs
= do { ctxt' <- kcHsContext ctxt
- ; cons' <- mappM (wrapLocM kc_con_decl) cons
+ ; cons' <- mapM (wrapLocM kc_con_decl) cons
; return (decl {tcdTyVars = tvs, tcdCtxt = ctxt', tcdCons = cons'}) }
where
-- doc comments are typechecked to Nothing here
return (ConDecl name expl ex_tvs' ex_ctxt' details' res' Nothing)
kc_con_details (PrefixCon btys)
- = do { btys' <- mappM kc_larg_ty btys
+ = do { btys' <- mapM kc_larg_ty btys
; return (PrefixCon btys') }
kc_con_details (InfixCon bty1 bty2)
= do { bty1' <- kc_larg_ty bty1
; bty2' <- kc_larg_ty bty2
; return (InfixCon bty1' bty2') }
kc_con_details (RecCon fields)
- = do { fields' <- mappM kc_field fields
+ = do { fields' <- mapM kc_field fields
; return (RecCon fields') }
kc_field (ConDeclField fld bty d) = do { bty' <- kc_larg_ty bty
; unbox_strict <- doptM Opt_UnboxStrictFields
; empty_data_decls <- doptM Opt_EmptyDataDecls
; kind_signatures <- doptM Opt_KindSignatures
+ ; existential_ok <- doptM Opt_ExistentialQuantification
; gadt_ok <- doptM Opt_GADTs
; is_boot <- tcIsHsBoot -- Are we compiling an hs-boot file?
+ ; let ex_ok = existential_ok || gadt_ok -- Data cons can have existential context
-- Check that we don't use GADT syntax in H98 world
; checkTc (gadt_ok || h98_syntax) (badGadtDecl tc_name)
-- Check that the stupid theta is empty for a GADT-style declaration
; checkTc (null stupid_theta || h98_syntax) (badStupidTheta tc_name)
+ -- Check that a newtype has exactly one constructor
+ -- Do this before checking for empty data decls, so that
+ -- we don't suggest -XEmptyDataDecls for newtypes
+ ; checkTc (new_or_data == DataType || isSingleton cons)
+ (newtypeConError tc_name (length cons))
+
-- Check that there's at least one condecl,
-- or else we're reading an hs-boot file, or -XEmptyDataDecls
; checkTc (not (null cons) || empty_data_decls || is_boot)
(emptyConDeclsErr tc_name)
- -- Check that a newtype has exactly one constructor
- ; checkTc (new_or_data == DataType || isSingleton cons)
- (newtypeConError tc_name (length cons))
-
; tycon <- fixM (\ tycon -> do
- { data_cons <- mappM (addLocM (tcConDecl unbox_strict tycon final_tvs))
+ { data_cons <- mapM (addLocM (tcConDecl unbox_strict ex_ok tycon final_tvs))
cons
; tc_rhs <-
if null cons && is_boot -- In a hs-boot file, empty cons means
tcdFDs = fundeps, tcdSigs = sigs, tcdATs = ats} )
= tcTyVarBndrs tvs $ \ tvs' -> do
{ ctxt' <- tcHsKindedContext ctxt
- ; fds' <- mappM (addLocM tc_fundep) fundeps
- ; atss <- mappM (addLocM (tcTyClDecl1 (const Recursive))) ats
+ ; fds' <- mapM (addLocM tc_fundep) fundeps
+ ; atss <- mapM (addLocM (tcTyClDecl1 (const Recursive))) ats
-- NB: 'ats' only contains "type family" and "data family"
-- declarations as well as type family defaults
; let ats' = zipWith setTyThingPoss atss (map (tcdTyVars . unLoc) ats)
tycon_name = tyConName (classTyCon clas)
tc_isrec = calc_isrec tycon_name
in
- buildClass class_name tvs' ctxt' fds' ats'
+ buildClass False {- Must include unfoldings for selectors -}
+ class_name tvs' ctxt' fds' ats'
sig_stuff tc_isrec)
; return (AClass clas : ats')
-- NB: Order is important due to the call to `mkGlobalThings' when
-- tying the the type and class declaration type checking knot.
}
where
- tc_fundep (tvs1, tvs2) = do { tvs1' <- mappM tcLookupTyVar tvs1 ;
- ; tvs2' <- mappM tcLookupTyVar tvs2 ;
+ tc_fundep (tvs1, tvs2) = do { tvs1' <- mapM tcLookupTyVar tvs1 ;
+ ; tvs2' <- mapM tcLookupTyVar tvs2 ;
; return (tvs1', tvs2') }
-- For each AT argument compute the position of the corresponding class
tcTyClDecl1 calc_isrec
(ForeignType {tcdLName = L _ tc_name, tcdExtName = tc_ext_name})
- = returnM [ATyCon (mkForeignTyCon tc_name tc_ext_name liftedTypeKind 0)]
+ = return [ATyCon (mkForeignTyCon tc_name tc_ext_name liftedTypeKind 0)]
-----------------------------------
tcConDecl :: Bool -- True <=> -funbox-strict_fields
+ -> Bool -- True <=> -XExistentialQuantificaton or -XGADTs
-> TyCon -> [TyVar]
-> ConDecl Name
-> TcM DataCon
-tcConDecl unbox_strict tycon tc_tvs -- Data types
+tcConDecl unbox_strict existential_ok tycon tc_tvs -- Data types
(ConDecl name _ tvs ctxt details res_ty _)
- = tcTyVarBndrs tvs $ \ tvs' -> do
+ = addErrCtxt (dataConCtxt name) $
+ tcTyVarBndrs tvs $ \ tvs' -> do
{ ctxt' <- tcHsKindedContext ctxt
+ ; checkTc (existential_ok || (null tvs && null (unLoc ctxt)))
+ (badExistential name)
; (univ_tvs, ex_tvs, eq_preds, data_tc) <- tcResultType tycon tc_tvs tvs' res_ty
; let
-- Tiresome: tidy the tyvar binders, since tc_tvs and tvs' may have the same OccNames
tc_datacon is_infix field_lbls btys
= do { let bangs = map getBangStrictness btys
- ; arg_tys <- mappM tcHsBangType btys
+ ; arg_tys <- mapM tcHsBangType btys
; buildDataCon (unLoc name) is_infix
(argStrictness unbox_strict bangs arg_tys)
(map unLoc field_lbls)
| null cls_cycles
= return ()
| otherwise
- = do { mappM_ recClsErr cls_cycles
+ = do { mapM_ recClsErr cls_cycles
; failM } -- Give up now, because later checkValidTyCl
-- will loop if the synonym is recursive
where
OpenSynTyCon _ _ -> return ()
SynonymTyCon ty -> checkValidType syn_ctxt ty
| otherwise
- = -- Check the context on the data decl
- checkValidTheta (DataTyCtxt name) (tyConStupidTheta tc) `thenM_`
+ = do -- Check the context on the data decl
+ checkValidTheta (DataTyCtxt name) (tyConStupidTheta tc)
-- Check arg types of data constructors
- mappM_ (checkValidDataCon tc) data_cons `thenM_`
+ mapM_ (checkValidDataCon tc) data_cons
-- Check that fields with the same name share a type
- mappM_ check_fields groups
+ mapM_ check_fields groups
where
syn_ctxt = TySynCtxt name
addErrCtxt (dataConCtxt con) $
do { checkTc (dataConTyCon con == tc) (badDataConTyCon con)
; checkValidType ctxt (dataConUserType con)
- ; ifM (isNewTyCon tc) (checkNewDataCon con)
+ ; checkValidMonoType (dataConOrigResTy con)
+ -- Disallow MkT :: T (forall a. a->a)
+ -- Reason: it's really the argument of an equality constraint
+ ; when (isNewTyCon tc) (checkNewDataCon con)
}
where
ctxt = ConArgCtxt (dataConName con)
; checkValidTheta (ClassSCCtxt (className cls)) theta
-- Check the class operations
- ; mappM_ (check_op constrained_class_methods) op_stuff
+ ; mapM_ (check_op constrained_class_methods) op_stuff
-- Check that if the class has generic methods, then the
-- class has only one parameter. We can't do generic
---------------------------------------------------------------------
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")]
+ = 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)]
+ = sep [ptext (sLit "Constructors") <+> ppr con1 <+> ptext (sLit "and") <+> ppr con2,
+ ptext (sLit "give different types for field"), quotes (ppr field_name)]
-dataConCtxt con = ptext SLIT("In the definition of data constructor") <+> quotes (ppr con)
+dataConCtxt con = ptext (sLit "In the definition of data constructor") <+> quotes (ppr con)
-classOpCtxt sel_id tau = sep [ptext SLIT("When checking the class method:"),
+classOpCtxt sel_id tau = sep [ptext (sLit "When checking the class method:"),
nest 2 (ppr sel_id <+> dcolon <+> ppr tau)]
nullaryClassErr cls
- = ptext SLIT("No parameters for class") <+> quotes (ppr cls)
+ = ptext (sLit "No parameters for class") <+> quotes (ppr cls)
classArityErr cls
- = vcat [ptext SLIT("Too many parameters for class") <+> quotes (ppr cls),
- parens (ptext SLIT("Use -XMultiParamTypeClasses to allow multi-parameter classes"))]
+ = vcat [ptext (sLit "Too many parameters for class") <+> quotes (ppr cls),
+ parens (ptext (sLit "Use -XMultiParamTypeClasses to allow multi-parameter classes"))]
classFunDepsErr cls
- = vcat [ptext SLIT("Fundeps in class") <+> quotes (ppr cls),
- parens (ptext SLIT("Use -XFunctionalDependencies to allow fundeps"))]
+ = vcat [ptext (sLit "Fundeps in class") <+> quotes (ppr cls),
+ parens (ptext (sLit "Use -XFunctionalDependencies to allow fundeps"))]
noClassTyVarErr clas op
- = sep [ptext SLIT("The class method") <+> quotes (ppr op),
- ptext SLIT("mentions none of the type variables of the class") <+>
+ = sep [ptext (sLit "The class method") <+> quotes (ppr op),
+ ptext (sLit "mentions none of the type variables of the class") <+>
ppr clas <+> hsep (map ppr (classTyVars clas))]
genericMultiParamErr clas
- = ptext SLIT("The multi-parameter class") <+> quotes (ppr clas) <+>
- ptext SLIT("cannot have generic methods")
+ = ptext (sLit "The multi-parameter class") <+> quotes (ppr clas) <+>
+ ptext (sLit "cannot have generic methods")
badGenericMethodType op op_ty
- = hang (ptext SLIT("Generic method type is too complex"))
+ = hang (ptext (sLit "Generic method type is too complex"))
4 (vcat [ppr op <+> dcolon <+> ppr op_ty,
- ptext SLIT("You can only use type variables, arrows, lists, and tuples")])
+ ptext (sLit "You can only use type variables, arrows, lists, and tuples")])
recSynErr syn_decls
= setSrcSpan (getLoc (head sorted_decls)) $
- addErr (sep [ptext SLIT("Cycle in type synonym declarations:"),
+ addErr (sep [ptext (sLit "Cycle in type synonym declarations:"),
nest 2 (vcat (map ppr_decl sorted_decls))])
where
sorted_decls = sortLocated syn_decls
recClsErr cls_decls
= setSrcSpan (getLoc (head sorted_decls)) $
- addErr (sep [ptext SLIT("Cycle in class declarations (via superclasses):"),
+ addErr (sep [ptext (sLit "Cycle in class declarations (via superclasses):"),
nest 2 (vcat (map ppr_decl sorted_decls))])
where
sorted_decls = sortLocated cls_decls
le (L l1 _) (L l2 _) = l1 <= l2
badDataConTyCon data_con
- = hang (ptext SLIT("Data constructor") <+> quotes (ppr data_con) <+>
- ptext SLIT("returns type") <+> quotes (ppr (dataConTyCon data_con)))
- 2 (ptext SLIT("instead of its parent type"))
+ = hang (ptext (sLit "Data constructor") <+> quotes (ppr data_con) <+>
+ ptext (sLit "returns type") <+> quotes (ppr (dataConTyCon data_con)))
+ 2 (ptext (sLit "instead of its parent type"))
badGadtDecl tc_name
- = vcat [ ptext SLIT("Illegal generalised algebraic data declaration for") <+> quotes (ppr tc_name)
- , nest 2 (parens $ ptext SLIT("Use -XGADTs to allow GADTs")) ]
+ = vcat [ ptext (sLit "Illegal generalised algebraic data declaration for") <+> quotes (ppr tc_name)
+ , nest 2 (parens $ ptext (sLit "Use -XGADTs to allow GADTs")) ]
+
+badExistential con_name
+ = hang (ptext (sLit "Data constructor") <+> quotes (ppr con_name) <+>
+ ptext (sLit "has existential type variables, or a context"))
+ 2 (parens $ ptext (sLit "Use -XExistentialQuantification or -XGADTs to allow this"))
badStupidTheta tc_name
- = ptext SLIT("A data type declared in GADT style cannot have a context:") <+> quotes (ppr tc_name)
+ = ptext (sLit "A data type declared in GADT style cannot have a context:") <+> quotes (ppr tc_name)
newtypeConError tycon n
- = sep [ptext SLIT("A newtype must have exactly one constructor,"),
- nest 2 $ ptext SLIT("but") <+> quotes (ppr tycon) <+> ptext SLIT("has") <+> speakN n ]
+ = sep [ptext (sLit "A newtype must have exactly one constructor,"),
+ nest 2 $ ptext (sLit "but") <+> quotes (ppr tycon) <+> ptext (sLit "has") <+> speakN n ]
newtypeExError con
- = sep [ptext SLIT("A newtype constructor cannot have an existential context,"),
- nest 2 $ ptext SLIT("but") <+> quotes (ppr con) <+> ptext SLIT("does")]
+ = sep [ptext (sLit "A newtype constructor cannot have an existential context,"),
+ nest 2 $ ptext (sLit "but") <+> quotes (ppr con) <+> ptext (sLit "does")]
newtypeStrictError con
- = sep [ptext SLIT("A newtype constructor cannot have a strictness annotation,"),
- nest 2 $ ptext SLIT("but") <+> quotes (ppr con) <+> ptext SLIT("does")]
+ = sep [ptext (sLit "A newtype constructor cannot have a strictness annotation,"),
+ nest 2 $ ptext (sLit "but") <+> quotes (ppr con) <+> ptext (sLit "does")]
newtypePredError con
- = sep [ptext SLIT("A newtype constructor must have a return type of form T a1 ... an"),
- nest 2 $ ptext SLIT("but") <+> quotes (ppr con) <+> ptext SLIT("does not")]
+ = sep [ptext (sLit "A newtype constructor must have a return type of form T a1 ... an"),
+ nest 2 $ ptext (sLit "but") <+> quotes (ppr con) <+> ptext (sLit "does not")]
newtypeFieldErr con_name n_flds
- = sep [ptext SLIT("The constructor of a newtype must have exactly one field"),
- nest 2 $ ptext SLIT("but") <+> quotes (ppr con_name) <+> ptext SLIT("has") <+> speakN n_flds]
+ = sep [ptext (sLit "The constructor of a newtype must have exactly one field"),
+ nest 2 $ ptext (sLit "but") <+> quotes (ppr con_name) <+> ptext (sLit "has") <+> speakN n_flds]
badSigTyDecl tc_name
- = vcat [ ptext SLIT("Illegal kind signature") <+>
+ = vcat [ ptext (sLit "Illegal kind signature") <+>
quotes (ppr tc_name)
- , nest 2 (parens $ ptext SLIT("Use -XKindSignatures to allow kind signatures")) ]
+ , nest 2 (parens $ ptext (sLit "Use -XKindSignatures to allow kind signatures")) ]
badFamInstDecl tc_name
- = vcat [ ptext SLIT("Illegal family instance for") <+>
+ = vcat [ ptext (sLit "Illegal family instance for") <+>
quotes (ppr tc_name)
- , nest 2 (parens $ ptext SLIT("Use -XTypeFamilies to allow indexed type families")) ]
+ , nest 2 (parens $ ptext (sLit "Use -XTypeFamilies to allow indexed type families")) ]
badGadtIdxTyDecl tc_name
- = vcat [ ptext SLIT("Illegal generalised algebraic data declaration for") <+>
+ = vcat [ ptext (sLit "Illegal generalised algebraic data declaration for") <+>
quotes (ppr tc_name)
- , nest 2 (parens $ ptext SLIT("Family instances can not yet use GADT declarations")) ]
+ , nest 2 (parens $ ptext (sLit "Family instances can not yet use GADT declarations")) ]
tooManyParmsErr tc_name
- = ptext SLIT("Family instance has too many parameters:") <+>
+ = ptext (sLit "Family instance has too many parameters:") <+>
quotes (ppr tc_name)
tooFewParmsErr arity
- = ptext SLIT("Family instance has too few parameters; expected") <+>
+ = ptext (sLit "Family instance has too few parameters; expected") <+>
ppr arity
wrongNumberOfParmsErr exp_arity
- = ptext SLIT("Number of parameters must match family declaration; expected")
+ = ptext (sLit "Number of parameters must match family declaration; expected")
<+> ppr exp_arity
badBootFamInstDeclErr =
- ptext SLIT("Illegal family instance in hs-boot file")
+ ptext (sLit "Illegal family instance in hs-boot file")
wrongKindOfFamily family =
- ptext SLIT("Wrong category of family instance; declaration was for a") <+>
+ ptext (sLit "Wrong category of family instance; declaration was for a") <+>
kindOfFamily
where
- kindOfFamily | isSynTyCon family = ptext SLIT("type synonym")
- | isAlgTyCon family = ptext SLIT("data type")
+ kindOfFamily | isSynTyCon family = ptext (sLit "type synonym")
+ | isAlgTyCon family = ptext (sLit "data type")
| otherwise = pprPanic "wrongKindOfFamily" (ppr family)
emptyConDeclsErr tycon
- = sep [quotes (ppr tycon) <+> ptext SLIT("has no constructors"),
- nest 2 $ ptext SLIT("(-XEmptyDataDecls permits this)")]
+ = sep [quotes (ppr tycon) <+> ptext (sLit "has no constructors"),
+ nest 2 $ ptext (sLit "(-XEmptyDataDecls permits this)")]
\end{code}