import CmdLineOpts ( DynFlags, DynFlag(..), dopt )
import HsSyn ( TyClDecl(..),
ConDecl(..), Sig(..), HsPred(..),
- tyClDeclName, hsTyVarNames,
+ tyClDeclName, hsTyVarNames, tyClDeclTyVars,
isIfaceSigDecl, isClassDecl, isSynDecl, isClassOpSig
)
import RnHsSyn ( RenamedTyClDecl, tyClDeclFVs )
-import BasicTypes ( RecFlag(..), NewOrData(..), isRec )
+import BasicTypes ( RecFlag(..), NewOrData(..) )
import HscTypes ( implicitTyThingIds )
+import Module ( Module )
import TcMonad
import TcEnv ( TcEnv, RecTcEnv, TcTyThing(..), TyThing(..), TyThingDetails(..),
- tcExtendKindEnv, tcLookup, tcExtendGlobalEnv, tcExtendGlobalValEnv )
-import TcTyDecls ( tcTyDecl1, kcConDetails, mkNewTyConRep )
-import TcClassDcl ( tcClassDecl1 )
+ tcExtendKindEnv, tcLookup, tcExtendGlobalEnv, tcExtendGlobalValEnv,
+ isLocalThing )
+import TcTyDecls ( tcTyDecl, kcConDetails, checkValidTyCon )
+import TcClassDcl ( tcClassDecl1, checkValidClass )
+import TcInstDcls ( tcAddDeclCtxt )
import TcMonoType ( kcHsTyVars, kcHsType, kcHsLiftedSigType, kcHsContext, mkTyClTyVars )
-import TcType ( TcKind, newKindVar, zonkKindEnv )
-
+import TcMType ( newKindVar, zonkKindEnv )
import TcUnify ( unifyKind )
-import TcInstDcls ( tcAddDeclCtxt )
-import Type ( Kind, mkArrowKind, 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 )
-import DataCon ( isNullaryDataCon )
+import TyCon ( TyCon, ArgVrcs, AlgTyConFlavour(..),
+ 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 NameEnv
import NameSet
import Outputable
import Maybes ( mapMaybe )
~~~~~~~~~~~~~~~~~
\begin{code}
tcTyAndClassDecls :: RecTcEnv -- Knot tying stuff
+ -> Module -- Current module
-> [RenamedTyClDecl]
- -> TcM TcEnv
+ -> TcM [TyThing] -- Returns newly defined things:
+ -- types, classes and implicit Ids
-tcTyAndClassDecls unf_env decls
+tcTyAndClassDecls unf_env this_mod decls
= sortByDependency decls `thenTc` \ groups ->
- tcGroups unf_env groups
+ tcGroups unf_env this_mod groups
-tcGroups unf_env []
+tcGroups unf_env this_mod []
= tcGetEnv `thenNF_Tc` \ env ->
- returnTc env
+ returnTc []
-tcGroups unf_env (group:groups)
- = tcGroup unf_env group `thenTc` \ env ->
- tcSetEnv env $
- tcGroups unf_env groups
+tcGroups unf_env this_mod (group:groups)
+ = tcGroup unf_env this_mod group `thenTc` \ (env, new_things1) ->
+ tcSetEnv env $
+ tcGroups unf_env this_mod groups `thenTc` \ new_things2 ->
+ returnTc (new_things1 ++ new_things2)
\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 ->
+tcGroup :: RecTcEnv -> Module -> SCC RenamedTyClDecl
+ -> TcM (TcEnv, -- Input env extended by types and classes only
+ [TyThing]) -- Things defined by this group
+
+tcGroup unf_env this_mod scc
+ = getDOptsTc `thenNF_Tc` \ dflags ->
-- Step 1
mapNF_Tc getInitialKind decls `thenNF_Tc` \ initial_kinds ->
tyclss, all_tyclss :: [TyThing]
tyclss = map (buildTyConOrClass dflags is_rec kind_env
- rec_vrcs rec_details) decls
+ rec_vrcs rec_details) decls
-- 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]
+ all_tyclss = [ATyCon (classTyCon clas) | AClass clas <- tyclss]
++ tyclss
-- Calculate variances, and (yes!) feed back into buildTyConOrClass.
rec_vrcs = calcTyConArgVrcs [tc | ATyCon tc <- all_tyclss]
in
-- Step 5
+ -- Extend the environment with the final
+ -- TyCons/Classes and check the decls
tcExtendGlobalEnv all_tyclss $
- mapTc (tcTyClDecl1 is_rec unf_env) decls `thenTc` \ tycls_details ->
+ mapTc (tcTyClDecl1 unf_env) decls `thenTc` \ tycls_details ->
-- Return results
tcGetEnv `thenNF_Tc` \ env ->
- returnTc (tycls_details, all_tyclss, env)
- ) `thenTc` \ (_, all_tyclss, env) ->
-
- tcSetEnv env $
+ returnTc (tycls_details, env, all_tyclss)
+ ) `thenTc` \ (_, env, all_tyclss) ->
- 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 ()
+ -- Step 7: Check validity
+ traceTc (text "ready for validity check") `thenTc_`
+ tcSetEnv env (
+ mapTc_ (checkValidTyCl this_mod) decls
) `thenTc_`
-
traceTc (text "done") `thenTc_`
-
- -- Step 7
- -- Extend the environment with the final TyCons/Classes
- -- and their implicit Ids
- tcExtendGlobalValEnv (implicitTyThingIds all_tyclss) tcGetEnv
+
+ let
+ implicit_things = [AnId id | id <- implicitTyThingIds all_tyclss]
+ new_things = all_tyclss ++ implicit_things
+ in
+ returnTc (env, new_things)
where
is_rec = 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 unf_env decl
+ | isClassDecl decl = tcAddDeclCtxt decl (tcClassDecl1 decl)
+ | otherwise = tcAddDeclCtxt decl (tcTyDecl unf_env 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
+ = tcLookup (tcdName decl) `thenNF_Tc` \ (AGlobal thing) ->
+ if not (isLocalThing this_mod thing) then
+ -- Don't bother to check validity for non-local things
+ returnTc ()
+ 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 decl
- = kcHsTyVars (tcdTyVars decl) `thenNF_Tc` \ arg_kinds ->
- newKindVar `thenNF_Tc` \ result_kind ->
+ = kcHsTyVars (tyClDeclTyVars decl) `thenNF_Tc` \ arg_kinds ->
+ newKindVar `thenNF_Tc` \ result_kind ->
returnNF_Tc (tcdName decl, mk_kind arg_kinds result_kind)
mk_kind tvs_w_kinds res_kind = foldr (mkArrowKind . snd) res_kind tvs_w_kinds
kcHsType rhs `thenTc` \ rhs_kind ->
unifyKind result_kind rhs_kind
+kcTyClDecl (ForeignType {}) = returnTc ()
+
kcTyClDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = context, tcdCons = con_decls})
= kcTyClDeclBody decl $ \ result_kind ->
kcHsContext context `thenTc_`
AThing kind -> kind
-- For some odd reason, a class doesn't include its kind
- (tyvars_w_kinds, result_kind) = zipFunTys (hsTyVarNames (tcdTyVars decl)) kind
+ (tyvars_w_kinds, result_kind) = zipFunTys (hsTyVarNames (tyClDeclTyVars decl)) kind
in
tcExtendKindEnv tyvars_w_kinds (thing_inside result_kind)
\end{code}
+
%************************************************************************
%* *
\subsection{Step 4: Building the tycon/class}
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
+ NewType -> NewTyCon (mkNewTyConRep tycon)
+ DataType | all (null . dataConOrigArgTys) data_cons -> EnumTyCon
+ | otherwise -> DataTyCon
+ -- 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 dflags is_rec kenv rec_vrcs rec_details
+ (ForeignType {tcdName = tycon_name, tcdExtName = tycon_ext_name})
+ = ATyCon (mkForeignTyCon tycon_name tycon_ext_name liftedTypeKind 0 [])
buildTyConOrClass dflags is_rec kenv rec_vrcs rec_details
(ClassDecl {tcdName = class_name, tcdTyVars = tyvar_names,
argvrcs dict_con
clas -- Yes! It's a dictionary
flavour
+ is_rec
+ -- 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 = 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
+--
+-- 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}
%************************************************************************
%* *
projects / ghc-hetmet.git / blobdiff