#include "HsVersions.h"
import HsSyn ( TyClDecl(..), HsConDetails(..), HsTyVarBndr(..),
- ConDecl(..), Sig(..), BangType(..), HsBang(..),
- tyClDeclTyVars, getBangType, getBangStrictness
+ ConDecl(..), Sig(..), BangType(..), HsBang(..), NewOrData(..),
+ tyClDeclTyVars, getBangType, getBangStrictness, isSynDecl,
+ LTyClDecl, tcdName, LHsTyVarBndr
)
-import RnHsSyn ( RenamedTyClDecl, RenamedConDecl )
-import BasicTypes ( RecFlag(..), NewOrData(..), StrictnessMark(..) )
+import BasicTypes ( RecFlag(..), StrictnessMark(..) )
import HscTypes ( implicitTyThings )
-import BuildTyCl ( buildClass, buildAlgTyCon, buildSynTyCon, buildDataCon )
+import BuildTyCl ( buildClass, buildAlgTyCon, buildSynTyCon, buildDataCon,
+ mkDataTyConRhs, mkNewTyConRhs )
import TcRnMonad
import TcEnv ( TcTyThing(..), TyThing(..),
- tcLookup, tcLookupGlobal, tcExtendGlobalEnv,
+ tcLookupLocated, tcLookupLocatedGlobal,
+ tcExtendGlobalEnv, tcExtendKindEnv,
tcExtendRecEnv, tcLookupTyVar )
-import TcTyDecls ( calcTyConArgVrcs, calcRecFlags, calcCycleErrs )
+import TcTyDecls ( calcTyConArgVrcs, calcRecFlags, calcClassCycles, calcSynCycles )
import TcClassDcl ( tcClassSigs, tcAddDeclCtxt )
-import TcHsType ( kcHsTyVars, kcHsLiftedSigType, kcHsSigType, kcCheckHsType,
+import TcHsType ( kcHsTyVars, kcHsLiftedSigType, kcHsSigType, kcHsType,
kcHsContext, tcTyVarBndrs, tcHsKindedType, tcHsKindedContext )
import TcMType ( newKindVar, checkValidTheta, checkValidType, checkFreeness,
UserTypeCtxt(..), SourceTyCtxt(..) )
import TcUnify ( unifyKind )
-import TcType ( TcKind, ThetaType, TcType,
+import TcType ( TcKind, ThetaType, TcType, tyVarsOfType,
mkArrowKind, liftedTypeKind,
tcSplitSigmaTy, tcEqType )
import Type ( splitTyConApp_maybe, pprThetaArrow, pprParendType )
import FieldLabel ( fieldLabelName, fieldLabelType )
import Generics ( validGenericMethodType, canDoGenerics )
-import Class ( Class, className, classTyCon, DefMeth(..), classBigSig )
-import TyCon ( TyCon, ArgVrcs, DataConDetails(..),
+import Class ( Class, className, classTyCon, DefMeth(..), classBigSig, classTyVars )
+import TyCon ( TyCon, ArgVrcs,
tyConDataCons, mkForeignTyCon, isProductTyCon, isRecursiveTyCon,
tyConTheta, getSynTyConDefn, tyConDataCons, isSynTyCon, tyConName )
import DataCon ( DataCon, dataConWrapId, dataConName, dataConSig, dataConFieldLabels )
import Var ( TyVar, idType, idName )
-import Name ( Name, getSrcLoc )
+import VarSet ( elemVarSet )
+import Name ( Name )
import Outputable
import Util ( zipLazy, isSingleton, notNull )
+import List ( partition )
+import SrcLoc ( Located(..), unLoc, getLoc )
import ListSetOps ( equivClasses )
+import Digraph ( SCC(..) )
import CmdLineOpts ( DynFlag( Opt_GlasgowExts, Opt_Generics, Opt_UnboxStrictFields ) )
\end{code}
@TyThing@s. @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
\begin{code}
-tcTyAndClassDecls :: [RenamedTyClDecl]
+tcTyAndClassDecls :: [LTyClDecl Name]
-> TcM TcGblEnv -- Input env extended by types and classes
-- and their implicit Ids,DataCons
tcTyAndClassDecls decls
-- See notes with checkCycleErrs
checkCycleErrs decls
- ; tyclss <- fixM (\ rec_tyclss ->
- do { lcl_things <- mappM getInitialKind decls
- -- Extend the local env with kinds, and
- -- the global env with the knot-tied results
- ; let { gbl_things = mkGlobalThings decls rec_tyclss }
- ; tcExtendRecEnv gbl_things lcl_things $ do
-
- -- The local type environment is populated with
- -- {"T" -> ARecTyCon k, ...}
- -- and the global type envt with
- -- {"T" -> ATyCon T, ...}
- -- where k is T's (unzonked) kind
- -- T is the loop-tied TyCon itself
- -- We must populate the environment with the loop-tied T's right
- -- away, because the kind checker may "fault in" some type
- -- constructors that recursively mention T
-
- -- Kind-check the declarations, returning kind-annotated decls
- { kc_decls <- mappM kcTyClDecl decls
-
- -- Calculate variances and rec-flag
- ; let { calc_vrcs = calcTyConArgVrcs rec_tyclss
- ; calc_rec = calcRecFlags rec_tyclss }
-
- ; mappM (tcTyClDecl calc_vrcs calc_rec) kc_decls
- }})
+ ; (syn_tycons, alg_tyclss) <- fixM (\ ~(rec_syn_tycons, rec_alg_tyclss) ->
+ do { let { -- Calculate variances and rec-flag
+ ; (syn_decls, alg_decls) = partition (isSynDecl . unLoc) decls }
+
+ -- Extend the global env with the knot-tied results
+ -- for data types and classes
+ --
+ -- We must populate the environment with the loop-tied T's right
+ -- away, because the kind checker may "fault in" some type
+ -- constructors that recursively mention T
+ ; let { gbl_things = mkGlobalThings alg_decls rec_alg_tyclss }
+ ; tcExtendRecEnv gbl_things $ do
+
+ -- Kind-check the declarations
+ { (kc_syn_decls, kc_alg_decls) <- kcTyClDecls syn_decls alg_decls
+
+ ; let { calc_vrcs = calcTyConArgVrcs (rec_syn_tycons ++ rec_alg_tyclss)
+ ; calc_rec = calcRecFlags rec_alg_tyclss
+ ; tc_decl = addLocM (tcTyClDecl calc_vrcs calc_rec) }
+ -- Type-check the type synonyms, and extend the envt
+ ; syn_tycons <- tcSynDecls calc_vrcs kc_syn_decls
+ ; tcExtendGlobalEnv syn_tycons $ do
+
+ -- Type-check the data types and classes
+ { alg_tyclss <- mappM tc_decl kc_alg_decls
+ ; return (syn_tycons, alg_tyclss)
+ }}})
-- Finished with knot-tying now
-- Extend the environment with the finished things
- ; tcExtendGlobalEnv tyclss $ do
+ ; tcExtendGlobalEnv (syn_tycons ++ alg_tyclss) $ do
-- Perform the validity check
{ traceTc (text "ready for validity check")
- ; mappM_ checkValidTyCl decls
+ ; mappM_ (addLocM checkValidTyCl) decls
; traceTc (text "done")
-- Add the implicit things;
-- we want them in the environment because
-- they may be mentioned in interface files
- ; let { implicit_things = concatMap implicitTyThings tyclss }
- ; traceTc ((text "Adding" <+> ppr tyclss) $$ (text "and" <+> ppr implicit_things))
+ ; let { implicit_things = concatMap implicitTyThings alg_tyclss }
+ ; traceTc ((text "Adding" <+> ppr alg_tyclss) $$ (text "and" <+> ppr implicit_things))
; tcExtendGlobalEnv implicit_things getGblEnv
}}
-mkGlobalThings :: [RenamedTyClDecl] -- The decls
+mkGlobalThings :: [LTyClDecl Name] -- The decls
-> [TyThing] -- Knot-tied, in 1-1 correspondence with the decls
-> [(Name,TyThing)]
-- Driven by the Decls, and treating the TyThings lazily
mkGlobalThings decls things
= map mk_thing (decls `zipLazy` things)
where
- mk_thing (ClassDecl {tcdName = name}, ~(AClass cl)) = (name, AClass cl)
- mk_thing (decl, ~(ATyCon tc)) = (tcdName decl, ATyCon tc)
+ mk_thing (L _ (ClassDecl {tcdLName = L _ name}), ~(AClass cl))
+ = (name, AClass cl)
+ mk_thing (L _ decl, ~(ATyCon tc))
+ = (tcdName decl, ATyCon tc)
\end{code}
depends on *all the uses of class D*. For example, the use of
Monad c in bop's type signature means that D must have kind Type->Type.
-\begin{code}
-------------------------------------------------------------------------
-getInitialKind :: TyClDecl Name -> TcM (Name, TcTyThing)
-
--- Note the lazy pattern match on the ATyCon etc
--- Exactly the same reason as the zipLay above
-
-getInitialKind (TyData {tcdName = name})
- = newKindVar `thenM` \ kind ->
- returnM (name, ARecTyCon kind)
-
-getInitialKind (TySynonym {tcdName = name})
- = newKindVar `thenM` \ kind ->
- returnM (name, ARecTyCon kind)
-
-getInitialKind (ClassDecl {tcdName = name})
- = newKindVar `thenM` \ kind ->
- returnM (name, ARecClass kind)
+However type synonyms work differently. They can have kinds which don't
+just involve (->) and *:
+ type R = Int# -- Kind #
+ type S a = Array# a -- Kind * -> #
+ type T a b = (# a,b #) -- Kind * -> * -> (# a,b #)
+So we must infer their kinds from their right-hand sides *first* and then
+use them, whereas for the mutually recursive data types D we bring into
+scope kind bindings D -> k, where k is a kind variable, and do inference.
+\begin{code}
+kcTyClDecls syn_decls alg_decls
+ = do { -- First extend the kind env with each data
+ -- type and class, mapping them to a type variable
+ alg_kinds <- mappM getInitialKind alg_decls
+ ; tcExtendKindEnv alg_kinds $ do
+
+ -- Now kind-check the type synonyms, in dependency order
+ -- We do these differently to data type and classes,
+ -- because a type synonym can be an unboxed type
+ -- type Foo = Int#
+ -- and a kind variable can't unify with UnboxedTypeKind
+ -- So we infer their kinds in dependency order
+ { (kc_syn_decls, syn_kinds) <- kcSynDecls (calcSynCycles syn_decls)
+ ; tcExtendKindEnv syn_kinds $ do
+
+ -- Now kind-check the data type and class declarations,
+ -- returning kind-annotated decls
+ { kc_alg_decls <- mappM (wrapLocM kcTyClDecl) alg_decls
+
+ ; return (kc_syn_decls, kc_alg_decls) }}}
------------------------------------------------------------------------
-kcTyClDecl :: RenamedTyClDecl -> TcM RenamedTyClDecl
+getInitialKind :: LTyClDecl Name -> TcM (Name, TcKind)
+
+getInitialKind decl
+ = newKindVar `thenM` \ kind ->
+ returnM (unLoc (tcdLName (unLoc decl)), kind)
+
+----------------
+kcSynDecls :: [SCC (LTyClDecl Name)]
+ -> TcM ([LTyClDecl Name], -- Kind-annotated decls
+ [(Name,TcKind)]) -- Kind bindings
+kcSynDecls []
+ = return ([], [])
+kcSynDecls (group : groups)
+ = do { (decl, nk) <- kcSynDecl group
+ ; (decls, nks) <- tcExtendKindEnv [nk] (kcSynDecls groups)
+ ; return (decl:decls, nk:nks) }
+
+----------------
+kcSynDecl :: SCC (LTyClDecl Name)
+ -> TcM (LTyClDecl Name, -- Kind-annotated decls
+ (Name,TcKind)) -- Kind bindings
+kcSynDecl (AcyclicSCC ldecl@(L loc decl))
+ = tcAddDeclCtxt decl $
+ kcHsTyVars (tcdTyVars decl) (\ k_tvs ->
+ do { traceTc (text "kcd1" <+> ppr (unLoc (tcdLName decl)) <+> brackets (ppr (tcdTyVars decl))
+ <+> brackets (ppr k_tvs))
+ ; (k_rhs, rhs_kind) <- kcHsType (tcdSynRhs decl)
+ ; traceTc (text "kcd2" <+> ppr (unLoc (tcdLName decl)))
+ ; let tc_kind = foldr (mkArrowKind . kindedTyVarKind) rhs_kind k_tvs
+ ; return (L loc (decl { tcdTyVars = k_tvs, tcdSynRhs = k_rhs }),
+ (unLoc (tcdLName decl), tc_kind)) })
+
+kcSynDecl (CyclicSCC decls)
+ = do { recSynErr decls; failM } -- Fail here to avoid error cascade
+ -- of out-of-scope tycons
-kcTyClDecl decl@(TySynonym {tcdSynRhs = rhs})
- = do { res_kind <- newKindVar
- ; kcTyClDeclBody decl res_kind $ \ tvs' ->
- do { rhs' <- kcCheckHsType rhs res_kind
- ; return (decl {tcdTyVars = tvs', tcdSynRhs = rhs'}) } }
+------------------------------------------------------------------------
+kcTyClDecl :: TyClDecl Name -> TcM (TyClDecl Name)
+ -- Not used for type synonyms (see kcSynDecl)
kcTyClDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdCons = cons})
- = kcTyClDeclBody decl liftedTypeKind $ \ tvs' ->
+ = kcTyClDeclBody decl $ \ tvs' ->
do { ctxt' <- kcHsContext ctxt
- ; cons' <- mappM kc_con_decl cons
+ ; 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 loc)
+ 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' loc)}
+ ; return (ConDecl name ex_tvs' ex_ctxt' details')}
kc_con_details (PrefixCon btys)
- = do { btys' <- mappM kc_arg_ty btys ; return (PrefixCon btys') }
+ = do { btys' <- mappM kc_larg_ty btys ; return (PrefixCon btys') }
kc_con_details (InfixCon bty1 bty2)
- = do { bty1' <- kc_arg_ty bty1; bty2' <- kc_arg_ty bty2; return (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; return (RecCon fields') }
- kc_field (fld, bty) = do { bty' <- kc_arg_ty bty ; return (fld, bty') }
+ kc_field (fld, bty) = do { bty' <- kc_larg_ty bty ; return (fld, bty') }
+
+ kc_larg_ty = wrapLocM kc_arg_ty
kc_arg_ty (BangType str ty) = do { ty' <- kc_arg_ty_body ty; return (BangType str ty') }
kc_arg_ty_body = case new_or_data of
-- going to remove the constructor while coercing it to a lifted type.
kcTyClDecl decl@(ClassDecl {tcdCtxt = ctxt, tcdSigs = sigs})
- = kcTyClDeclBody decl liftedTypeKind $ \ tvs' ->
+ = kcTyClDeclBody decl $ \ tvs' ->
do { ctxt' <- kcHsContext ctxt
- ; sigs' <- mappM kc_sig sigs
+ ; sigs' <- mappM (wrapLocM kc_sig) sigs
; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdSigs = sigs'}) }
where
- kc_sig (Sig nm op_ty loc) = do { op_ty' <- kcHsLiftedSigType op_ty
- ; return (Sig nm op_ty' loc) }
+ kc_sig (Sig nm op_ty) = do { op_ty' <- kcHsLiftedSigType op_ty
+ ; return (Sig nm op_ty') }
kc_sig other_sig = return other_sig
-kcTyClDecl decl@(ForeignType {})
+kcTyClDecl decl@(ForeignType {})
= return decl
-kcTyClDeclBody :: RenamedTyClDecl -> TcKind
- -> ([HsTyVarBndr Name] -> TcM a)
+kcTyClDeclBody :: TyClDecl Name
+ -> ([LHsTyVarBndr Name] -> TcM a)
-> TcM a
-- Extend the env with bindings for the tyvars, taken from
-- the kind of the tycon/class. Give it to the thing inside, and
-- check the result kind matches
-kcTyClDeclBody decl res_kind thing_inside
+kcTyClDeclBody decl thing_inside
= tcAddDeclCtxt decl $
kcHsTyVars (tyClDeclTyVars decl) $ \ kinded_tvs ->
- do { tc_ty_thing <- tcLookup (tcdName decl)
- ; let { tc_kind = case tc_ty_thing of
- ARecClass k -> k
- ARecTyCon k -> k
- }
+ do { tc_ty_thing <- tcLookupLocated (tcdLName decl)
+ ; let tc_kind = case tc_ty_thing of { AThing k -> k }
; unifyKind tc_kind (foldr (mkArrowKind . kindedTyVarKind)
- res_kind kinded_tvs)
+ liftedTypeKind kinded_tvs)
; thing_inside kinded_tvs }
-kindedTyVarKind (KindedTyVar _ k) = k
+kindedTyVarKind (L _ (KindedTyVar _ k)) = k
\end{code}
%************************************************************************
\begin{code}
+tcSynDecls :: (Name -> ArgVrcs) -> [LTyClDecl Name] -> TcM [TyThing]
+tcSynDecls calc_vrcs [] = return []
+tcSynDecls calc_vrcs (decl : decls)
+ = do { syn_tc <- addLocM (tcSynDecl calc_vrcs) decl
+ ; syn_tcs <- tcExtendGlobalEnv [syn_tc] (tcSynDecls calc_vrcs decls)
+ ; return (syn_tc : syn_tcs) }
+
+tcSynDecl calc_vrcs
+ (TySynonym {tcdLName = L _ tc_name, tcdTyVars = tvs, tcdSynRhs = rhs_ty})
+ = tcTyVarBndrs tvs $ \ tvs' -> do
+ { traceTc (text "tcd1" <+> ppr tc_name)
+ ; rhs_ty' <- tcHsKindedType rhs_ty
+ ; return (ATyCon (buildSynTyCon tc_name tvs' rhs_ty' (calc_vrcs tc_name))) }
+
+--------------------
tcTyClDecl :: (Name -> ArgVrcs) -> (Name -> RecFlag)
- -> RenamedTyClDecl -> TcM TyThing
+ -> TyClDecl Name -> TcM TyThing
tcTyClDecl calc_vrcs calc_isrec decl
= tcAddDeclCtxt decl (tcTyClDecl1 calc_vrcs calc_isrec decl)
tcTyClDecl1 calc_vrcs calc_isrec
- (TySynonym {tcdName = tc_name, tcdTyVars = tvs, tcdSynRhs = rhs_ty})
- = tcTyVarBndrs tvs $ \ tvs' -> do
- { rhs_ty' <- tcHsKindedType rhs_ty
- ; return (ATyCon (buildSynTyCon tc_name tvs' rhs_ty' arg_vrcs)) }
- where
- arg_vrcs = calc_vrcs tc_name
-
-tcTyClDecl1 calc_vrcs calc_isrec
(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdTyVars = tvs,
- tcdName = tc_name, tcdCons = cons})
+ tcdLName = L _ tc_name, tcdCons = cons})
= tcTyVarBndrs tvs $ \ tvs' -> do
{ ctxt' <- tcHsKindedContext ctxt
; want_generic <- doptM Opt_Generics
; tycon <- fixM (\ tycon -> do
- { cons' <- mappM (tcConDecl new_or_data tycon tvs' ctxt') cons
- ; buildAlgTyCon new_or_data tc_name tvs' ctxt'
- (DataCons cons') arg_vrcs is_rec
- (want_generic && canDoGenerics cons')
+ { data_cons <- mappM (addLocM (tcConDecl new_or_data tycon tvs' ctxt')) cons
+ ; let tc_rhs = case new_or_data of
+ DataType -> mkDataTyConRhs data_cons
+ NewType -> ASSERT( isSingleton data_cons )
+ mkNewTyConRhs (head data_cons)
+ ; buildAlgTyCon tc_name tvs' ctxt'
+ tc_rhs arg_vrcs is_rec
+ (want_generic && canDoGenerics data_cons)
})
; return (ATyCon tycon)
}
is_rec = calc_isrec tc_name
tcTyClDecl1 calc_vrcs calc_isrec
- (ClassDecl {tcdName = class_name, tcdTyVars = tvs,
+ (ClassDecl {tcdLName = L _ class_name, tcdTyVars = tvs,
tcdCtxt = ctxt, tcdMeths = meths,
tcdFDs = fundeps, tcdSigs = sigs} )
= tcTyVarBndrs tvs $ \ tvs' -> do
{ ctxt' <- tcHsKindedContext ctxt
- ; fds' <- mappM tc_fundep fundeps
+ ; fds' <- mappM (addLocM tc_fundep) fundeps
; sig_stuff <- tcClassSigs class_name sigs meths
; clas <- fixM (\ clas ->
let -- This little knot is just so we can get
tcTyClDecl1 calc_vrcs calc_isrec
- (ForeignType {tcdName = tc_name, tcdExtName = tc_ext_name})
+ (ForeignType {tcdLName = L _ tc_name, tcdExtName = tc_ext_name})
= returnM (ATyCon (mkForeignTyCon tc_name tc_ext_name liftedTypeKind 0 []))
-----------------------------------
tcConDecl :: NewOrData -> TyCon -> [TyVar] -> ThetaType
- -> RenamedConDecl -> TcM DataCon
+ -> ConDecl Name -> TcM DataCon
tcConDecl new_or_data tycon tyvars ctxt
- (ConDecl name ex_tvs ex_ctxt details src_loc)
- = addSrcLoc src_loc $
- tcTyVarBndrs ex_tvs $ \ ex_tvs' -> do
+ (ConDecl name ex_tvs ex_ctxt details)
+ = tcTyVarBndrs ex_tvs $ \ ex_tvs' -> do
{ ex_ctxt' <- tcHsKindedContext ex_ctxt
; unbox_strict <- doptM Opt_UnboxStrictFields
; let
tc_datacon field_lbls btys
- = do { arg_tys <- mappM (tcHsKindedType . getBangType) btys
- ; buildDataCon name
- (argStrictness unbox_strict tycon btys arg_tys)
- field_lbls
+ = do { let { ubtys = map unLoc btys }
+ ; arg_tys <- mappM (tcHsKindedType . getBangType) ubtys
+ ; buildDataCon (unLoc name)
+ (argStrictness unbox_strict tycon ubtys arg_tys)
+ (map unLoc field_lbls)
tyvars ctxt ex_tvs' ex_ctxt'
arg_tys tycon }
; case details of
tied, so we can look at things freely.
\begin{code}
-checkCycleErrs :: [TyClDecl Name] -> TcM ()
+checkCycleErrs :: [LTyClDecl Name] -> TcM ()
checkCycleErrs tyclss
- | null syn_cycles && null cls_cycles
+ | null cls_cycles
= return ()
| otherwise
- = do { mappM_ recSynErr syn_cycles
- ; mappM_ recClsErr cls_cycles
+ = do { mappM_ recClsErr cls_cycles
; failM } -- Give up now, because later checkValidTyCl
-- will loop if the synonym is recursive
where
- (syn_cycles, cls_cycles) = calcCycleErrs tyclss
+ cls_cycles = calcClassCycles tyclss
-checkValidTyCl :: RenamedTyClDecl -> TcM ()
+checkValidTyCl :: TyClDecl Name -> TcM ()
-- We do the validity check over declarations, rather than TyThings
-- only so that we can add a nice context with tcAddDeclCtxt
checkValidTyCl decl
= tcAddDeclCtxt decl $
- do { thing <- tcLookupGlobal (tcdName decl)
+ do { thing <- tcLookupLocatedGlobal (tcdLName decl)
; traceTc (text "Validity of" <+> ppr thing)
; case thing of
ATyCon tc -> checkValidTyCon tc
no_generics = null [() | (_, GenDefMeth) <- op_stuff]
check_op (sel_id, dm)
- = addErrCtxt (classOpCtxt sel_id) (
- checkValidTheta SigmaCtxt (tail theta) `thenM_`
+ = addErrCtxt (classOpCtxt sel_id tau) $ do
+ { checkValidTheta SigmaCtxt (tail theta)
-- The 'tail' removes the initial (C a) from the
-- class itself, leaving just the method type
- checkValidType (FunSigCtxt op_name) tau `thenM_`
+ ; checkValidType (FunSigCtxt op_name) tau
+
+ -- Check that the type mentions at least one of
+ -- the class type variables
+ ; checkTc (any (`elemVarSet` tyVarsOfType tau) tyvars)
+ (noClassTyVarErr cls sel_id)
-- Check that for a generic method, the type of
-- the method is sufficiently simple
- checkTc (dm /= GenDefMeth || validGenericMethodType op_ty)
+ ; checkTc (dm /= GenDefMeth || validGenericMethodType op_ty)
(badGenericMethodType op_name op_ty)
- )
+ }
where
op_name = idName sel_id
op_ty = idType sel_id
[ ppr n <+> dcolon <+> ppr ty
| (n,ty) <- fields `zip` arg_tys]))
-classOpCtxt sel_id = sep [ptext SLIT("When checking the class method:"),
- nest 2 (ppr sel_id <+> dcolon <+> ppr (idType sel_id))]
+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)
= vcat [ptext SLIT("Too many parameters for class") <+> quotes (ppr cls),
parens (ptext SLIT("Use -fglasgow-exts to allow multi-parameter classes"))]
+noClassTyVarErr clas op
+ = 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")
4 (vcat [ppr op <+> dcolon <+> ppr op_ty,
ptext SLIT("You can only use type variables, arrows, and tuples")])
-recSynErr tcs
- = addSrcLoc (getSrcLoc (head tcs)) $
+recSynErr syn_decls
+ = addSrcSpan (getLoc (head syn_decls)) $
addErr (sep [ptext SLIT("Cycle in type synonym declarations:"),
- nest 2 (vcat (map ppr_thing tcs))])
+ nest 2 (vcat (map ppr_decl syn_decls))])
+ where
+ ppr_decl (L loc decl) = ppr loc <> colon <+> ppr decl
-recClsErr clss
- = addSrcLoc (getSrcLoc (head clss)) $
+recClsErr cls_decls
+ = addSrcSpan (getLoc (head cls_decls)) $
addErr (sep [ptext SLIT("Cycle in class declarations (via superclasses):"),
- nest 2 (vcat (map ppr_thing clss))])
-
-ppr_thing :: Name -> SDoc
-ppr_thing n = ppr n <+> parens (ppr (getSrcLoc n))
-
+ nest 2 (vcat (map ppr_decl cls_decls))])
+ where
+ ppr_decl (L loc decl) = ppr loc <> colon <+> ppr (decl { tcdSigs = [] })
exRecConErr name
= ptext SLIT("Can't combine named fields with locally-quantified type variables")
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