\section[TcBinds]{TcBinds}
\begin{code}
-module TcBinds ( tcBindsAndThen, tcTopBinds,
+module TcBinds ( tcBindsAndThen, tcTopBinds, tcMonoBinds,
tcSpecSigs, tcBindWithSigs ) where
#include "HsVersions.h"
collectMonoBinders, andMonoBinds,
collectSigTysFromMonoBinds
)
-import RnHsSyn ( RenamedHsBinds, RenamedSig, RenamedMonoBinds )
+import RnHsSyn ( RenamedHsBinds, RenamedSig, RenamedMonoBinds,
+ RenamedTyClDecl )
import TcHsSyn ( TcMonoBinds, TcId, zonkId, mkHsLet )
import TcMonad
import Inst ( LIE, emptyLIE, mkLIE, plusLIE, InstOrigin(..),
newDicts, instToId
)
-import TcEnv ( tcExtendLocalValEnv, newLocalName )
-import TcUnify ( unifyTauTyLists, checkSigTyVars, sigCtxt )
+import TcEnv ( tcExtendLocalValEnv, tcExtendLocalValEnv2, newLocalName )
+import TcUnify ( unifyTauTyLists, checkSigTyVarsWrt, sigCtxt )
import TcSimplify ( tcSimplifyInfer, tcSimplifyInferCheck, tcSimplifyRestricted, tcSimplifyToDicts )
-import TcMonoType ( tcHsSigType, UserTypeCtxt(..),
- TcSigInfo(..), tcTySig, maybeSig, tcAddScopedTyVars
+import TcMonoType ( tcHsSigType, UserTypeCtxt(..), TcSigInfo(..),
+ tcTySig, maybeSig, tcSigPolyId, tcSigMonoId, tcAddScopedTyVars
)
import TcPat ( tcPat, tcSubPat, tcMonoPatBndr )
import TcSimplify ( bindInstsOfLocalFuns )
import TcMType ( newTyVar, newTyVarTy, newHoleTyVarTy,
- zonkTcTyVarToTyVar
+ zonkTcTyVarToTyVar, readHoleResult
)
-import TcType ( mkTyVarTy, mkForAllTys, mkFunTys, tyVarsOfType,
+import TcType ( TcTyVar, mkTyVarTy, mkForAllTys, mkFunTys, tyVarsOfType,
mkPredTy, mkForAllTy, isUnLiftedType,
unliftedTypeKind, liftedTypeKind, openTypeKind, eqKind
)
sigs is_rec `thenTc` \ (poly_binds, poly_lie, poly_ids) ->
-- Extend the environment to bind the new polymorphic Ids
- tcExtendLocalValEnv [(idName poly_id, poly_id) | poly_id <- poly_ids] $
+ tcExtendLocalValEnv poly_ids $
-- Build bindings and IdInfos corresponding to user pragmas
tcSpecSigs sigs `thenTc` \ (prag_binds, prag_lie) ->
binder_names = collectMonoBinders mbind
poly_ids = map mk_dummy binder_names
mk_dummy name = case maybeSig tc_ty_sigs name of
- Just (TySigInfo _ poly_id _ _ _ _ _ _) -> poly_id -- Signature
- Nothing -> mkLocalId name forall_a_a -- No signature
+ Just sig -> tcSigPolyId sig -- Signature
+ Nothing -> mkLocalId name forall_a_a -- No signature
in
returnTc (EmptyMonoBinds, emptyLIE, poly_ids)
) $
where
(tyvars, poly_id) =
case maybeSig tc_ty_sigs binder_name of
- Just (TySigInfo _ sig_poly_id sig_tyvars _ _ _ _ _) ->
+ Just (TySigInfo sig_poly_id sig_tyvars _ _ _ _ _) ->
(sig_tyvars, sig_poly_id)
Nothing -> (real_tyvars_to_gen, new_poly_id)
tcSimplifyRestricted doc tau_tvs lie_req `thenTc` \ (qtvs, lie_free, binds) ->
-- Check that signature type variables are OK
- checkSigsTyVars sigs `thenTc_`
+ checkSigsTyVars qtvs sigs `thenTc` \ final_qtvs ->
- returnTc (qtvs, lie_free, binds, [])
+ returnTc (final_qtvs, lie_free, binds, [])
else if null sigs then -- UNRESTRICTED CASE, NO TYPE SIGS
tcSimplifyInfer doc tau_tvs lie_req
else -- UNRESTRICTED CASE, WITH TYPE SIGS
-- CHECKING CASE: Unrestricted group, there are type signatures
- -- Check signature contexts are empty
+ -- Check signature contexts are identical
checkSigsCtxts sigs `thenTc` \ (sig_avails, sig_dicts) ->
-- Check that the needed dicts can be
tcSimplifyInferCheck doc tau_tvs sig_avails lie_req `thenTc` \ (forall_tvs, lie_free, dict_binds) ->
-- Check that signature type variables are OK
- checkSigsTyVars sigs `thenTc_`
+ checkSigsTyVars forall_tvs sigs `thenTc` \ final_qtvs ->
- returnTc (forall_tvs, lie_free, dict_binds, sig_dicts)
+ returnTc (final_qtvs, lie_free, dict_binds, sig_dicts)
where
- tysig_names = [name | (TySigInfo name _ _ _ _ _ _ _) <- sigs]
- is_mono_sig (TySigInfo _ _ _ theta _ _ _ _) = null theta
+ tysig_names = map (idName . tcSigPolyId) sigs
+ is_mono_sig (TySigInfo _ _ theta _ _ _ _) = null theta
doc = ptext SLIT("type signature(s) for") <+> pprBinders binder_names
-- We unify them because, with polymorphic recursion, their types
-- might not otherwise be related. This is a rather subtle issue.
-- ToDo: amplify
-checkSigsCtxts sigs@(TySigInfo _ id1 sig_tvs theta1 _ _ _ src_loc : other_sigs)
+checkSigsCtxts sigs@(TySigInfo id1 sig_tvs theta1 _ _ _ src_loc : other_sigs)
= tcAddSrcLoc src_loc $
mapTc_ check_one other_sigs `thenTc_`
if null theta1 then
returnTc (sig_avails, map instToId sig_dicts)
where
sig1_dict_tys = map mkPredTy theta1
- sig_meths = concat [insts | TySigInfo _ _ _ _ _ _ insts _ <- sigs]
+ sig_meths = concat [insts | TySigInfo _ _ _ _ _ insts _ <- sigs]
- check_one sig@(TySigInfo _ id _ theta _ _ _ src_loc)
+ check_one sig@(TySigInfo id _ theta _ _ _ _)
= tcAddErrCtxt (sigContextsCtxt id1 id) $
checkTc (equalLength theta theta1) sigContextsErr `thenTc_`
unifyTauTyLists sig1_dict_tys (map mkPredTy theta)
-checkSigsTyVars sigs = mapTc_ check_one sigs
+checkSigsTyVars :: [TcTyVar] -> [TcSigInfo] -> TcM [TcTyVar]
+checkSigsTyVars qtvs sigs
+ = mapTc check_one sigs `thenTc` \ sig_tvs_s ->
+ let
+ -- Sigh. Make sure that all the tyvars in the type sigs
+ -- appear in the returned ty var list, which is what we are
+ -- going to generalise over. Reason: we occasionally get
+ -- silly types like
+ -- type T a = () -> ()
+ -- f :: T a
+ -- f () = ()
+ -- Here, 'a' won't appear in qtvs, so we have to add it
+
+ sig_tvs = foldr (unionVarSet . mkVarSet) emptyVarSet sig_tvs_s
+ all_tvs = mkVarSet qtvs `unionVarSet` sig_tvs
+ in
+ returnTc (varSetElems all_tvs)
where
- check_one (TySigInfo _ id sig_tyvars sig_theta sig_tau _ _ src_loc)
+ check_one (TySigInfo id sig_tyvars sig_theta sig_tau _ _ src_loc)
= tcAddSrcLoc src_loc $
tcAddErrCtxt (ptext SLIT("When checking the type signature for")
<+> quotes (ppr id)) $
- tcAddErrCtxtM (sigCtxt sig_tyvars sig_theta sig_tau) $
- checkSigTyVars sig_tyvars (idFreeTyVars id)
+ tcAddErrCtxtM (sigCtxt id sig_tyvars sig_theta sig_tau) $
+ checkSigTyVarsWrt (idFreeTyVars id) sig_tyvars
\end{code}
@getTyVarsToGen@ decides what type variables to generalise over.
where
mk_bind (name, mono_id) = case maybeSig tc_ty_sigs name of
- Nothing -> (name, mono_id)
- Just (TySigInfo name poly_id _ _ _ _ _ _) -> (name, poly_id)
+ Nothing -> (name, mono_id)
+ Just sig -> (idName poly_id, poly_id)
+ where
+ poly_id = tcSigPolyId sig
tc_mb_pats EmptyMonoBinds
= returnTc (\ xve -> returnTc (EmptyMonoBinds, emptyLIE), emptyLIE, emptyBag, emptyBag, emptyLIE)
tc_mb_pats (FunMonoBind name inf matches locn)
= (case maybeSig tc_ty_sigs name of
- Just (TySigInfo _ _ _ _ _ mono_id _ _)
- -> returnNF_Tc mono_id
- Nothing -> newLocalName name `thenNF_Tc` \ bndr_name ->
- newTyVarTy openTypeKind `thenNF_Tc` \ bndr_ty ->
+ Just sig -> returnNF_Tc (tcSigMonoId sig)
+ Nothing -> newLocalName name `thenNF_Tc` \ bndr_name ->
+ newTyVarTy openTypeKind `thenNF_Tc` \ bndr_ty ->
-- NB: not a 'hole' tyvar; since there is no type
-- signature, we revert to ordinary H-M typechecking
-- which means the variable gets an inferred tau-type
- returnNF_Tc (mkLocalId bndr_name bndr_ty)
+ returnNF_Tc (mkLocalId bndr_name bndr_ty)
) `thenNF_Tc` \ bndr_id ->
let
bndr_ty = idType bndr_id
complete_it xve = tcAddSrcLoc locn $
- tcMatchesFun xve name bndr_ty matches `thenTc` \ (matches', lie) ->
+ tcMatchesFun xve name bndr_ty matches `thenTc` \ (matches', lie) ->
returnTc (FunMonoBind bndr_id inf matches' locn, lie)
in
returnTc (complete_it, emptyLIE, emptyBag, unitBag (name, bndr_id), emptyLIE)
-- so we don't have to do anything here.
tcPat tc_pat_bndr pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
+ readHoleResult pat_ty `thenTc` \ pat_ty' ->
let
complete_it xve = tcAddSrcLoc locn $
tcAddErrCtxt (patMonoBindsCtxt bind) $
- tcExtendLocalValEnv xve $
- tcGRHSs PatBindRhs grhss pat_ty `thenTc` \ (grhss', lie) ->
+ tcExtendLocalValEnv2 xve $
+ tcGRHSs PatBindRhs grhss pat_ty' `thenTc` \ (grhss', lie) ->
returnTc (PatMonoBind pat' grhss' locn, lie)
in
returnTc (complete_it, lie_req, tvs, ids, lie_avail)
-> newLocalName name `thenNF_Tc` \ bndr_name ->
tcMonoPatBndr bndr_name pat_ty
- Just (TySigInfo _ _ _ _ _ mono_id _ _)
- -> tcAddSrcLoc (getSrcLoc name) $
- tcSubPat pat_ty (idType mono_id) `thenTc` \ (co_fn, lie) ->
- returnTc (co_fn, lie, mono_id)
+ Just sig -> tcAddSrcLoc (getSrcLoc name) $
+ tcSubPat (idType mono_id) pat_ty `thenTc` \ (co_fn, lie) ->
+ returnTc (co_fn, lie, mono_id)
+ where
+ mono_id = tcSigMonoId sig
\end{code}
projects / ghc-hetmet.git / blobdiff