#include "HsVersions.h"
-import CmdLineOpts ( DynFlags, DynFlag(..), dopt )
import HsSyn ( TyClDecl(..),
ConDecl(..), Sig(..), HsPred(..),
tyClDeclName, hsTyVarNames, tyClDeclTyVars,
- isIfaceSigDecl, isClassDecl, isSynDecl, isClassOpSig
+ isTypeOrClassDecl, isClassDecl, isSynDecl, isClassOpSig
)
import RnHsSyn ( RenamedTyClDecl, tyClDeclFVs )
-import BasicTypes ( RecFlag(..), NewOrData(..), isRec )
-import HscTypes ( implicitTyThingIds )
-
-import TcMonad
-import TcEnv ( TcEnv, RecTcEnv, TcTyThing(..), TyThing(..), TyThingDetails(..),
- tcExtendKindEnv, tcLookup, tcExtendGlobalEnv, tcExtendGlobalValEnv )
-import TcTyDecls ( tcTyDecl1, kcConDetails, mkNewTyConRep )
+import BasicTypes ( RecFlag(..), NewOrData(..) )
+import HscTypes ( implicitTyThings )
+
+import TcRnMonad
+import TcEnv ( TcTyThing(..), TyThing(..), TyThingDetails(..),
+ tcExtendKindEnv, tcLookup, tcLookupGlobal, tcExtendGlobalEnv,
+ isLocalThing )
+import TcTyDecls ( tcTyDecl, kcConDetails )
import TcClassDcl ( tcClassDecl1 )
+import TcInstDcls ( tcAddDeclCtxt )
import TcMonoType ( kcHsTyVars, kcHsType, kcHsLiftedSigType, kcHsContext, mkTyClTyVars )
-import TcType ( TcKind, newKindVar, zonkKindEnv )
-
+import TcMType ( newKindVar, zonkKindEnv, checkValidTyCon, checkValidClass )
import TcUnify ( unifyKind )
-import TcInstDcls ( tcAddDeclCtxt )
-import Type ( Kind, mkArrowKind, liftedTypeKind, zipFunTys )
+import TcType ( Type, Kind, TcKind, mkArrowKind, liftedTypeKind, zipFunTys )
+import Type ( splitTyConApp_maybe )
import Variance ( calcTyConArgVrcs )
import Class ( Class, mkClass, classTyCon )
-import TyCon ( TyCon, tyConKind, ArgVrcs, AlgTyConFlavour(..),
- mkSynTyCon, mkAlgTyCon, mkClassTyCon, mkForeignTyCon )
-import DataCon ( isNullaryDataCon )
+import TyCon ( TyCon, ArgVrcs, AlgTyConFlavour(..), DataConDetails(..), visibleDataCons,
+ tyConKind, tyConTyVars, tyConDataCons, isNewTyCon,
+ mkSynTyCon, mkAlgTyCon, mkClassTyCon, mkForeignTyCon
+ )
+import TysWiredIn ( unitTy )
+import Subst ( substTyWith )
+import DataCon ( dataConOrigArgTys )
import Var ( varName )
import FiniteMap
import Digraph ( stronglyConnComp, SCC(..) )
-import Name ( Name, getSrcLoc, isTyVarName )
-import NameEnv ( NameEnv, mkNameEnv, lookupNameEnv_NF )
+import Name ( Name )
+import NameEnv
import NameSet
import Outputable
import Maybes ( mapMaybe )
-import ErrUtils ( Message )
-import HsDecls ( getClassDeclSysNames )
-import Generics ( mkTyConGenInfo )
\end{code}
The main function
~~~~~~~~~~~~~~~~~
\begin{code}
-tcTyAndClassDecls :: RecTcEnv -- Knot tying stuff
- -> [RenamedTyClDecl]
- -> TcM TcEnv
-
-tcTyAndClassDecls unf_env decls
- = sortByDependency decls `thenTc` \ groups ->
- tcGroups unf_env groups
-
-tcGroups unf_env []
- = tcGetEnv `thenNF_Tc` \ env ->
- returnTc env
-
-tcGroups unf_env (group:groups)
- = tcGroup unf_env group `thenTc` \ env ->
- tcSetEnv env $
- tcGroups unf_env groups
+tcTyAndClassDecls :: [RenamedTyClDecl]
+ -> TcM TcGblEnv -- Returns extended environment
+
+tcTyAndClassDecls decls
+ = tcGroups (stronglyConnComp edges)
+ where
+ edges = map mkEdges (filter isTypeOrClassDecl decls)
+
+tcGroups [] = getGblEnv
+
+tcGroups (group:groups)
+ = tcGroup group `thenM` \ env ->
+ setGblEnv env $
+ tcGroups groups
\end{code}
Dealing with a group
to tcTyClDecl1.
-Step 6: tcTyClDecl1 again
- For a recursive group only, check all the decls again, just
- but this time with the wimp flag off. Now we can check things
- like whether a function argument is an unlifted tuple, looking
- through type synonyms properly. We can't do that in Step 5.
-
-Step 7: Extend environment
+Step 6: Extend environment
We extend the type environment with bindings not only for the TyCons and Classes,
but also for their "implicit Ids" like data constructors and class selectors
+Step 7: checkValidTyCl
+ For a recursive group only, check all the decls again, just
+ to check all the side conditions on validity. We could not
+ do this before because we were in a mutually recursive knot.
+
+
The knot-tying parameters: @rec_details_list@ is an alist mapping @Name@s to
@TyThing@s. @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
\begin{code}
-tcGroup :: RecTcEnv -> SCC RenamedTyClDecl -> TcM TcEnv
-tcGroup unf_env scc
- = getDOptsTc `thenTc` \ dflags ->
- -- Step 1
- mapNF_Tc getInitialKind decls `thenNF_Tc` \ initial_kinds ->
+tcGroup :: SCC RenamedTyClDecl
+ -> TcM TcGblEnv -- Input env extended by types and classes
+ -- and their implicit Ids,DataCons
+
+tcGroup scc
+ = -- Step 1
+ mappM getInitialKind decls `thenM` \ initial_kinds ->
-- Step 2
- tcExtendKindEnv initial_kinds (mapTc kcTyClDecl decls) `thenTc_`
+ tcExtendKindEnv initial_kinds (mappM kcTyClDecl decls) `thenM_`
-- Step 3
- zonkKindEnv initial_kinds `thenNF_Tc` \ final_kinds ->
+ zonkKindEnv initial_kinds `thenM` \ final_kinds ->
+
+ -- Check for loops; if any are found, bale out now
+ -- because the compiler itself will loop otherwise!
+ checkNoErrs (checkLoops scc) `thenM` \ is_rec_tycon ->
-- Tie the knot
- traceTc (text "starting" <+> ppr final_kinds) `thenTc_`
- fixTc ( \ ~(rec_details_list, _, _) ->
+ traceTc (text "starting" <+> ppr final_kinds) `thenM_`
+ fixM ( \ ~(rec_details_list, _, rec_all_tyclss) ->
-- Step 4
let
kind_env = mkNameEnv final_kinds
rec_details = mkNameEnv rec_details_list
- tyclss, all_tyclss :: [TyThing]
- tyclss = map (buildTyConOrClass dflags is_rec kind_env
- rec_vrcs rec_details) decls
+ -- Calculate variances, and feed into buildTyConOrClass
+ rec_vrcs = calcTyConArgVrcs [tc | ATyCon tc <- rec_all_tyclss]
- -- Add the tycons that come from the classes
- -- We want them in the environment because
- -- they are mentioned in interface files
- all_tyclss = [ ATyCon (classTyCon clas) | AClass clas <- tyclss]
- ++ tyclss
+ build_one = buildTyConOrClass is_rec_tycon kind_env
+ rec_vrcs rec_details
+ tyclss = map build_one decls
- -- Calculate variances, and (yes!) feed back into buildTyConOrClass.
- rec_vrcs = calcTyConArgVrcs [tc | ATyCon tc <- all_tyclss]
in
-- Step 5
- tcExtendGlobalEnv all_tyclss $
- mapTc (tcTyClDecl1 is_rec unf_env) decls `thenTc` \ tycls_details ->
+ -- Extend the environment with the final
+ -- TyCons/Classes and check the decls
+ tcExtendGlobalEnv tyclss $
+ mappM tcTyClDecl1 decls `thenM` \ tycls_details ->
-- Return results
- tcGetEnv `thenNF_Tc` \ env ->
- returnTc (tycls_details, all_tyclss, env)
- ) `thenTc` \ (_, all_tyclss, env) ->
-
- tcSetEnv env $
-
- traceTc (text "ready for pass 2" <+> ppr (isRec is_rec)) `thenTc_`
-
- -- Step 6
- -- For a recursive group, check all the types again,
- -- this time with the wimp flag off
- (if isRec is_rec then
- mapTc_ (tcTyClDecl1 NonRecursive unf_env) decls
- else
- returnTc ()
- ) `thenTc_`
-
- traceTc (text "done") `thenTc_`
-
- -- Step 7
- -- Extend the environment with the final TyCons/Classes
- -- and their implicit Ids
- tcExtendGlobalValEnv (implicitTyThingIds all_tyclss) tcGetEnv
+ getGblEnv `thenM` \ env ->
+ returnM (tycls_details, env, tyclss)
+ ) `thenM` \ (_, env, tyclss) ->
+
+ -- Step 7: Check validity
+ setGblEnv env $
+
+ traceTc (text "ready for validity check") `thenM_`
+ getModule `thenM` \ mod ->
+ mappM_ (checkValidTyCl mod) decls `thenM_`
+ traceTc (text "done") `thenM_`
+
+ let -- Add the tycons that come from the classes
+ -- We want them in the environment because
+ -- they are mentioned in interface files
+ implicit_things = implicitTyThings tyclss
+ in
+ traceTc ((text "Adding" <+> ppr tyclss) $$ (text "and" <+> ppr implicit_things)) `thenM_`
+ tcExtendGlobalEnv implicit_things getGblEnv
where
- is_rec = case scc of
- AcyclicSCC _ -> NonRecursive
- CyclicSCC _ -> Recursive
-
decls = case scc of
AcyclicSCC decl -> [decl]
CyclicSCC decls -> decls
-tcTyClDecl1 is_rec unf_env decl
- | isClassDecl decl = tcAddDeclCtxt decl (tcClassDecl1 is_rec unf_env decl)
- | otherwise = tcAddDeclCtxt decl (tcTyDecl1 is_rec unf_env decl)
+tcTyClDecl1 decl
+ | isClassDecl decl = tcAddDeclCtxt decl (tcClassDecl1 decl)
+ | otherwise = tcAddDeclCtxt decl (tcTyDecl decl)
+
+-- We do the validity check over declarations, rather than TyThings
+-- only so that we can add a nice context with tcAddDeclCtxt
+checkValidTyCl this_mod decl
+ = tcLookupGlobal (tcdName decl) `thenM` \ thing ->
+ if not (isLocalThing this_mod thing) then
+ -- Don't bother to check validity for non-local things
+ returnM ()
+ else
+ tcAddDeclCtxt decl $
+ case thing of
+ ATyCon tc -> checkValidTyCon tc
+ AClass cl -> checkValidClass cl
\end{code}
%************************************************************************
\begin{code}
-getInitialKind :: RenamedTyClDecl -> NF_TcM (Name, TcKind)
+getInitialKind :: RenamedTyClDecl -> TcM (Name, TcKind)
getInitialKind decl
- = kcHsTyVars (tyClDeclTyVars decl) `thenNF_Tc` \ arg_kinds ->
- newKindVar `thenNF_Tc` \ result_kind ->
- returnNF_Tc (tcdName decl, mk_kind arg_kinds result_kind)
+ = kcHsTyVars (tyClDeclTyVars decl) `thenM` \ arg_kinds ->
+ newKindVar `thenM` \ result_kind ->
+ returnM (tcdName decl, mk_kind arg_kinds result_kind)
mk_kind tvs_w_kinds res_kind = foldr (mkArrowKind . snd) res_kind tvs_w_kinds
\end{code}
kcTyClDecl decl@(TySynonym {tcdSynRhs = rhs})
= kcTyClDeclBody decl $ \ result_kind ->
- kcHsType rhs `thenTc` \ rhs_kind ->
+ kcHsType rhs `thenM` \ rhs_kind ->
unifyKind result_kind rhs_kind
-kcTyClDecl (ForeignType {}) = returnTc ()
+kcTyClDecl (ForeignType {}) = returnM ()
kcTyClDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = context, tcdCons = con_decls})
= kcTyClDeclBody decl $ \ result_kind ->
- kcHsContext context `thenTc_`
- mapTc_ kc_con_decl con_decls
+ kcHsContext context `thenM_`
+ mappM_ kc_con_decl (visibleDataCons con_decls)
where
- kc_con_decl (ConDecl _ _ ex_tvs ex_ctxt details loc)
- = kcHsTyVars ex_tvs `thenNF_Tc` \ kind_env ->
+ kc_con_decl (ConDecl _ ex_tvs ex_ctxt details loc)
+ = kcHsTyVars ex_tvs `thenM` \ kind_env ->
tcExtendKindEnv kind_env $
kcConDetails new_or_data ex_ctxt details
kcTyClDecl decl@(ClassDecl {tcdCtxt = context, tcdSigs = class_sigs})
= kcTyClDeclBody decl $ \ result_kind ->
- kcHsContext context `thenTc_`
- mapTc_ kc_sig (filter isClassOpSig class_sigs)
+ kcHsContext context `thenM_`
+ mappM_ kc_sig (filter isClassOpSig class_sigs)
where
kc_sig (ClassOpSig _ _ op_ty loc) = kcHsLiftedSigType op_ty
-- check the result kind matches
kcTyClDeclBody decl thing_inside
= tcAddDeclCtxt decl $
- tcLookup (tcdName decl) `thenNF_Tc` \ thing ->
+ tcLookup (tcdName decl) `thenM` \ thing ->
let
kind = case thing of
AGlobal (ATyCon tc) -> tyConKind tc
\end{code}
+
%************************************************************************
%* *
\subsection{Step 4: Building the tycon/class}
\begin{code}
buildTyConOrClass
- :: DynFlags
- -> RecFlag -> NameEnv Kind
+ :: (Name -> AlgTyConFlavour -> RecFlag) -- Whether it's recursive
+ -> NameEnv Kind
-> FiniteMap TyCon ArgVrcs -> NameEnv TyThingDetails
-> RenamedTyClDecl -> TyThing
-buildTyConOrClass dflags is_rec kenv rec_vrcs rec_details
- (TySynonym {tcdName = tycon_name, tcdTyVars = tyvar_names})
+buildTyConOrClass rec_tycon kenv rec_vrcs rec_details
+ (TySynonym {tcdName = tycon_name, tcdTyVars = tyvar_names})
= ATyCon tycon
where
tycon = mkSynTyCon tycon_name tycon_kind arity tyvars rhs_ty argvrcs
SynTyDetails rhs_ty = lookupNameEnv_NF rec_details tycon_name
argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
-buildTyConOrClass dflags is_rec kenv rec_vrcs rec_details
- (TyData {tcdND = data_or_new, tcdName = tycon_name, tcdTyVars = tyvar_names,
- tcdNCons = nconstrs, tcdSysNames = sys_names})
+buildTyConOrClass rec_tycon kenv rec_vrcs rec_details
+ (TyData {tcdND = data_or_new, tcdName = tycon_name,
+ tcdTyVars = tyvar_names})
= ATyCon tycon
where
tycon = mkAlgTyCon tycon_name tycon_kind tyvars ctxt argvrcs
- data_cons nconstrs sel_ids
- flavour is_rec gen_info
-
- gen_info | not (dopt Opt_Generics dflags) = Nothing
- | otherwise = mkTyConGenInfo tycon sys_names
+ data_cons sel_ids flavour
+ (rec_tycon tycon_name flavour) gen_info
- DataTyDetails ctxt data_cons sel_ids = lookupNameEnv_NF rec_details tycon_name
+ DataTyDetails ctxt data_cons sel_ids gen_info = lookupNameEnv_NF rec_details tycon_name
tycon_kind = lookupNameEnv_NF kenv tycon_name
tyvars = mkTyClTyVars tycon_kind tyvar_names
argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
+ -- Watch out! mkTyConApp asks whether the tycon is a NewType,
+ -- so flavour has to be able to answer this question without consulting rec_details
flavour = case data_or_new of
- NewType -> NewTyCon (mkNewTyConRep tycon)
- DataType | all isNullaryDataCon data_cons -> EnumTyCon
- | otherwise -> DataTyCon
-
-buildTyConOrClass dflags is_rec kenv rec_vrcs rec_details
- (ForeignType {tcdName = tycon_name})
- = ATyCon (mkForeignTyCon tycon_name liftedTypeKind 0 [])
-
-buildTyConOrClass dflags is_rec kenv rec_vrcs rec_details
- (ClassDecl {tcdName = class_name, tcdTyVars = tyvar_names,
- tcdFDs = fundeps, tcdSysNames = name_list} )
+ NewType -> NewTyCon (mkNewTyConRep tycon)
+ DataType | all_nullary data_cons -> EnumTyCon
+ | otherwise -> DataTyCon
+
+ all_nullary (DataCons cons) = all (null . dataConOrigArgTys) cons
+ all_nullary other = False -- Safe choice for unknown data types
+ -- NB (null . dataConOrigArgTys). It used to say isNullaryDataCon
+ -- but that looks at the *representation* arity, and that in turn
+ -- depends on deciding whether to unpack the args, and that
+ -- depends on whether it's a data type or a newtype --- so
+ -- in the recursive case we can get a loop. This version is simple!
+
+buildTyConOrClass rec_tycon kenv rec_vrcs rec_details
+ (ForeignType {tcdName = tycon_name, tcdExtName = tycon_ext_name})
+ = ATyCon (mkForeignTyCon tycon_name tycon_ext_name liftedTypeKind 0 [])
+
+buildTyConOrClass rec_tycon kenv rec_vrcs rec_details
+ (ClassDecl {tcdName = class_name, tcdTyVars = tyvar_names, tcdFDs = fundeps} )
= AClass clas
where
- (tycon_name, _, _, _) = getClassDeclSysNames name_list
clas = mkClass class_name tyvars fds
sc_theta sc_sel_ids op_items
tycon
argvrcs dict_con
clas -- Yes! It's a dictionary
flavour
-
- ClassDetails sc_theta sc_sel_ids op_items dict_con = lookupNameEnv_NF rec_details class_name
+ (rec_tycon class_name flavour)
+ -- A class can be recursive, and in the case of newtypes
+ -- this matters. For example
+ -- class C a where { op :: C b => a -> b -> Int }
+ -- Because C has only one operation, it is represented by
+ -- a newtype, and it should be a *recursive* newtype.
+ -- [If we don't make it a recursive newtype, we'll expand the
+ -- newtype like a synonym, but that will lead toan inifinite type
+
+ ClassDetails sc_theta sc_sel_ids op_items dict_con tycon_name
+ = lookupNameEnv_NF rec_details class_name
class_kind = lookupNameEnv_NF kenv class_name
tyvars = mkTyClTyVars class_kind tyvar_names
argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
- n_fields = length sc_sel_ids + length op_items
- flavour | n_fields == 1 = NewTyCon (mkNewTyConRep tycon)
- | otherwise = DataTyCon
+ flavour = case dataConOrigArgTys dict_con of
+ -- The tyvars in the datacon are the same as in the class
+ [rep_ty] -> NewTyCon rep_ty
+ other -> DataTyCon
-- We can find the functional dependencies right away,
-- and it is vital to do so. Why? Because in the next pass
bogusVrcs = panic "Bogus tycon arg variances"
\end{code}
+\begin{code}
+mkNewTyConRep :: TyCon -- The original type constructor
+ -> Type -- Chosen representation type
+ -- (guaranteed not to be another newtype)
+
+-- Find the representation type for this newtype TyCon
+-- Remember that the representation type is the ultimate representation
+-- type, looking through other newtypes.
+--
+-- The non-recursive newtypes are easy, because they look transparent
+-- to splitTyConApp_maybe, but recursive ones really are represented as
+-- TyConApps (see TypeRep).
+--
+-- The trick is to to deal correctly with recursive newtypes
+-- such as newtype T = MkT T
+
+mkNewTyConRep tc
+ = go [] tc
+ where
+ -- Invariant: tc is a NewTyCon
+ -- tcs have been seen before
+ go tcs tc
+ | tc `elem` tcs = unitTy
+ | otherwise
+ = let
+ rep_ty = head (dataConOrigArgTys (head (tyConDataCons tc)))
+ in
+ case splitTyConApp_maybe rep_ty of
+ Nothing -> rep_ty
+ Just (tc', tys) | not (isNewTyCon tc') -> rep_ty
+ | otherwise -> go1 (tc:tcs) tc' tys
+
+ go1 tcs tc tys = substTyWith (tyConTyVars tc) tys (go tcs tc)
+\end{code}
%************************************************************************
%* *
Dependency analysis
~~~~~~~~~~~~~~~~~~~
\begin{code}
-sortByDependency :: [RenamedTyClDecl] -> TcM [SCC RenamedTyClDecl]
-sortByDependency decls
+checkLoops :: SCC RenamedTyClDecl
+ -> TcM (Name -> AlgTyConFlavour -> RecFlag)
+-- Check for illegal loops,
+-- a) type synonyms
+-- b) superclass hierarchy
+--
+-- Also return a function that says which tycons are recursive.
+-- Remember:
+-- a newtype is recursive if it is part of a recursive
+-- group consisting only of newtype and synonyms
+
+checkLoops (AcyclicSCC _)
+ = returnM (\ _ _ -> NonRecursive)
+
+checkLoops (CyclicSCC decls)
= let -- CHECK FOR CLASS CYCLES
- cls_sccs = stronglyConnComp (mapMaybe mkClassEdges tycl_decls)
- cls_cycles = [ decls | CyclicSCC decls <- cls_sccs]
+ cls_edges = mapMaybe mkClassEdges decls
+ cls_cycles = findCycles cls_edges
in
- checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
+ mapM_ (cycleErr "class") cls_cycles `thenM_`
let -- CHECK FOR SYNONYM CYCLES
- syn_sccs = stronglyConnComp (filter is_syn_decl edges)
- syn_cycles = [ decls | CyclicSCC decls <- syn_sccs]
-
+ syn_edges = map mkEdges (filter isSynDecl decls)
+ syn_cycles = findCycles syn_edges
in
- checkTc (null syn_cycles) (typeCycleErr syn_cycles) `thenTc_`
+ mapM_ (cycleErr "type synonym") syn_cycles `thenM_`
- -- DO THE MAIN DEPENDENCY ANALYSIS
- let
- decl_sccs = stronglyConnComp edges
+ let -- CHECK FOR NEWTYPE CYCLES
+ newtype_edges = map mkEdges (filter is_nt_cycle_decl decls)
+ newtype_cycles = findCycles newtype_edges
+ rec_newtypes = mkNameSet [tcdName d | ds <- newtype_cycles, d <- ds]
+
+ rec_tycon name (NewTyCon _)
+ | name `elemNameSet` rec_newtypes = Recursive
+ | otherwise = NonRecursive
+ rec_tycon name other_flavour = Recursive
in
- returnTc decl_sccs
- where
- tycl_decls = filter (not . isIfaceSigDecl) decls
- edges = map mkEdges tycl_decls
-
- is_syn_decl (d, _, _) = isSynDecl d
-\end{code}
+ returnM rec_tycon
-Edges in Type/Class decls
-~~~~~~~~~~~~~~~~~~~~~~~~~
+----------------------------------------------------
+-- A class with one op and no superclasses, or vice versa,
+-- is treated just like a newtype.
+-- It's a bit unclean that this test is repeated in buildTyConOrClass
+is_nt_cycle_decl (TySynonym {}) = True
+is_nt_cycle_decl (TyData {tcdND = NewType}) = True
+is_nt_cycle_decl (ClassDecl {tcdCtxt = ctxt, tcdSigs = sigs}) = length ctxt + length sigs == 1
+is_nt_cycle_decl other = False
-\begin{code}
-tyClDeclFTVs :: RenamedTyClDecl -> [Name]
- -- Find the free non-tyvar vars
-tyClDeclFTVs d = foldNameSet add [] (tyClDeclFVs d)
- where
- add n fvs | isTyVarName n = fvs
- | otherwise = n : fvs
+----------------------------------------------------
+findCycles edges = [ ds | CyclicSCC ds <- stronglyConnComp edges]
+
+----------------------------------------------------
+mkEdges :: RenamedTyClDecl -> (RenamedTyClDecl, Name, [Name])
+mkEdges decl = (decl, tyClDeclName decl, nameSetToList (tyClDeclFVs decl))
----------------------------------------------------
-- mk_cls_edges looks only at the context of class decls
-- superclass hierarchy
mkClassEdges :: RenamedTyClDecl -> Maybe (RenamedTyClDecl, Name, [Name])
-
mkClassEdges decl@(ClassDecl {tcdCtxt = ctxt, tcdName = name}) = Just (decl, name, [c | HsClassP c _ <- ctxt])
mkClassEdges other_decl = Nothing
-
-mkEdges :: RenamedTyClDecl -> (RenamedTyClDecl, Name, [Name])
-mkEdges decl = (decl, tyClDeclName decl, tyClDeclFTVs decl)
\end{code}
%************************************************************************
\begin{code}
-typeCycleErr, classCycleErr :: [[RenamedTyClDecl]] -> Message
+cycleErr :: String -> [RenamedTyClDecl] -> TcM ()
-typeCycleErr syn_cycles
- = vcat (map (pp_cycle "Cycle in type declarations:") syn_cycles)
-
-classCycleErr cls_cycles
- = vcat (map (pp_cycle "Cycle in class declarations:") cls_cycles)
+cycleErr kind_of_decl decls
+ = addErrAt loc (ppr_cycle kind_of_decl decls)
+ where
+ loc = tcdLoc (head decls)
-pp_cycle str decls
- = hang (text str)
+ppr_cycle kind_of_decl decls
+ = hang (ptext SLIT("Cycle in") <+> text kind_of_decl <+> ptext SLIT("declarations:"))
4 (vcat (map pp_decl decls))
where
- pp_decl decl
- = hsep [quotes (ppr name), ptext SLIT("at"), ppr (getSrcLoc name)]
- where
- name = tyClDeclName decl
-
+ pp_decl decl = hsep [quotes (ppr (tcdName decl)),
+ ptext SLIT("at"), ppr (tcdLoc decl)]
\end{code}
projects / ghc-hetmet.git / blobdiff