import Type
import Coercion
import TyCon
+import TypeRep
import DataCon
import Class
import Var
-- (they recover, so that we get more than one error each
-- round)
- -- (1) Do class instance declarations and instances of indexed
- -- types
- ; let { idxty_decls = filter (isIdxTyDecl . unLoc) tycl_decls }
+ -- (1) Do class and family instance declarations
+ ; let { idxty_decls = filter (isFamInstDecl . unLoc) tycl_decls }
; local_info_tycons <- mappM tcLocalInstDecl1 inst_decls
; idx_tycons <- mappM tcIdxTyInstDeclTL idxty_decls
-- (4) Compute instances from "deriving" clauses;
-- This stuff computes a context for the derived instance
-- decl, so it needs to know about all the instances possible
- ; (deriv_inst_info, deriv_binds) <- tcDeriving tycl_decls deriv_decls
+ -- NB: class instance declarations can contain derivings as
+ -- part of associated data type declarations
+ ; (deriv_inst_info, deriv_binds) <- tcDeriving tycl_decls inst_decls
+ deriv_decls
; addInsts deriv_inst_info $ do {
; gbl_env <- getGblEnv
-- !!!TODO: Need to perform this check for the TyThing of type functions,
-- too.
tcIdxTyInstDeclTL ldecl@(L loc decl) =
- do { tything <- tcIdxTyInstDecl ldecl
+ do { tything <- tcFamInstDecl ldecl
; setSrcSpan loc $
when (isAssocFamily tything) $
addErr $ assocInClassErr (tcdName decl)
; (tyvars, theta, tau) <- tcHsInstHead poly_ty
-- Next, process any associated types.
- ; idx_tycons <- mappM tcIdxTyInstDecl ats
+ ; idx_tycons <- mappM tcFamInstDecl ats
-- Now, check the validity of the instance.
; (clas, inst_tys) <- checkValidInstHead tau
-- Finally, construct the Core representation of the instance.
-- (This no longer includes the associated types.)
- ; dfun_name <- newDFunName clas inst_tys (srcSpanStart loc)
+ ; dfun_name <- newDFunName clas inst_tys loc
; overlap_flag <- getOverlapFlag
- ; let dfun = mkDictFunId dfun_name tyvars theta clas inst_tys
+ ; let (eq_theta,dict_theta) = partition isEqPred theta
+ theta' = eq_theta ++ dict_theta
+ dfun = mkDictFunId dfun_name tyvars theta' clas inst_tys
ispec = mkLocalInstance dfun overlap_flag
; return ([InstInfo { iSpec = ispec,
dfun_id = instanceDFunId ispec
rigid_info = InstSkol
inst_ty = idType dfun_id
+ loc = srcLocSpan (getSrcLoc dfun_id)
in
-- Prime error recovery
recoverM (returnM emptyLHsBinds) $
- setSrcSpan (srcLocSpan (getSrcLoc dfun_id)) $
+ setSrcSpan loc $
addErrCtxt (instDeclCtxt2 (idType dfun_id)) $
-- Instantiate the instance decl with skolem constants
-- Instantiate the super-class context with inst_tys
sc_theta' = substTheta (zipOpenTvSubst class_tyvars inst_tys') sc_theta
+ (eq_sc_theta',dict_sc_theta') = partition isEqPred sc_theta'
origin = SigOrigin rigid_info
+ (eq_dfun_theta',dict_dfun_theta') = partition isEqPred dfun_theta'
in
-- Create dictionary Ids from the specified instance contexts.
getInstLoc InstScOrigin `thenM` \ sc_loc ->
- newDictBndrs sc_loc sc_theta' `thenM` \ sc_dicts ->
+ newDictBndrs sc_loc dict_sc_theta' `thenM` \ sc_dicts ->
getInstLoc origin `thenM` \ inst_loc ->
- newDictBndrs inst_loc dfun_theta' `thenM` \ dfun_arg_dicts ->
+ mkMetaCoVars eq_sc_theta' `thenM` \ sc_covars ->
+ mkEqInsts eq_sc_theta' (map mkWantedCo sc_covars) `thenM` \ wanted_sc_eqs ->
+ mkCoVars eq_dfun_theta' `thenM` \ dfun_covars ->
+ mkEqInsts eq_dfun_theta' (map mkGivenCo $ mkTyVarTys dfun_covars) `thenM` \ dfun_eqs ->
+ newDictBndrs inst_loc dict_dfun_theta' `thenM` \ dfun_dicts ->
newDictBndr inst_loc (mkClassPred clas inst_tys') `thenM` \ this_dict ->
-- Default-method Ids may be mentioned in synthesised RHSs,
-- but they'll already be in the environment.
-- Typecheck the methods
let -- These insts are in scope; quite a few, eh?
- avail_insts = [this_dict] ++ dfun_arg_dicts ++ sc_dicts
+ dfun_insts = dfun_eqs ++ dfun_dicts
+ wanted_sc_insts = wanted_sc_eqs ++ sc_dicts
+ given_sc_eqs = map (updateEqInstCoercion (mkGivenCo . TyVarTy . fromWantedCo "tcInstDecl2") ) wanted_sc_eqs
+ given_sc_insts = given_sc_eqs ++ sc_dicts
+ avail_insts = [this_dict] ++ dfun_insts ++ given_sc_insts
in
tcMethods origin clas inst_tyvars'
dfun_theta' inst_tys' avail_insts
-- Figure out bindings for the superclass context
-- Don't include this_dict in the 'givens', else
- -- sc_dicts get bound by just selecting from this_dict!!
+ -- wanted_sc_insts get bound by just selecting from this_dict!!
addErrCtxt superClassCtxt
(tcSimplifySuperClasses inst_loc
- dfun_arg_dicts sc_dicts) `thenM` \ sc_binds ->
+ dfun_insts wanted_sc_insts) `thenM` \ sc_binds ->
-- It's possible that the superclass stuff might unified one
-- of the inst_tyavars' with something in the envt
dict_constr = classDataCon clas
scs_and_meths = map instToId sc_dicts ++ meth_ids
this_dict_id = instToId this_dict
- inline_prag | null dfun_arg_dicts = []
- | otherwise = [InlinePrag (Inline AlwaysActive True)]
+ inline_prag | null dfun_insts = []
+ | otherwise = [L loc (InlinePrag (Inline AlwaysActive True))]
-- Always inline the dfun; this is an experimental decision
-- because it makes a big performance difference sometimes.
-- Often it means we can do the method selection, and then
-- See Note [Inline dfuns] below
dict_rhs
- = mkHsConApp dict_constr inst_tys' (map HsVar scs_and_meths)
+ = mkHsConApp dict_constr (inst_tys' ++ mkTyVarTys sc_covars) (map HsVar scs_and_meths)
-- We don't produce a binding for the dict_constr; instead we
-- rely on the simplifier to unfold this saturated application
-- We do this rather than generate an HsCon directly, because
all_binds = dict_bind `consBag` (sc_binds `unionBags` meth_binds)
main_bind = noLoc $ AbsBinds
- inst_tyvars'
- (map instToId dfun_arg_dicts)
- [(inst_tyvars', dfun_id, this_dict_id,
- inline_prag ++ prags)]
+ (inst_tyvars' ++ dfun_covars)
+ (map instToId dfun_dicts)
+ [(inst_tyvars' ++ dfun_covars, dfun_id, this_dict_id, inline_prag ++ prags)]
all_binds
in
showLIE (text "instance") `thenM_`
returnM (unitBag main_bind)
+mkCoVars :: [PredType] -> TcM [TyVar]
+mkCoVars [] = return []
+mkCoVars (pred:preds) =
+ do { uniq <- newUnique
+ ; let name = mkSysTvName uniq FSLIT("mkCoVars")
+ ; let tv = mkCoVar name (PredTy pred)
+ ; tvs <- mkCoVars preds
+ ; return (tv:tvs)
+ }
+
+mkMetaCoVars :: [PredType] -> TcM [TyVar]
+mkMetaCoVars [] = return []
+mkMetaCoVars (EqPred ty1 ty2:preds) =
+ do { tv <- newMetaTyVar TauTv (mkCoKind ty1 ty2)
+ ; tvs <- mkMetaCoVars preds
+ ; return (tv:tvs)
+ }
+
tcMethods origin clas inst_tyvars' dfun_theta' inst_tys'
avail_insts op_items monobinds uprags
projects / ghc-hetmet.git / blobdiff