\section[TcBinds]{TcBinds}
\begin{code}
-module TcBinds ( tcBindsAndThen, tcTopBindsAndThen,
- tcPragmaSigs, tcBindWithSigs ) where
+module TcBinds ( tcBindsAndThen, tcTopBinds,
+ tcSpecSigs, tcBindWithSigs ) where
#include "HsVersions.h"
-import {-# SOURCE #-} TcGRHSs ( tcGRHSsAndBinds )
+import {-# SOURCE #-} TcMatches ( tcGRHSs, tcMatchesFun )
import {-# SOURCE #-} TcExpr ( tcExpr )
-import HsSyn ( HsExpr(..), HsBinds(..), MonoBinds(..), Sig(..), InPat(..), StmtCtxt(..),
- collectMonoBinders, andMonoBindList, andMonoBinds
+import HsSyn ( HsExpr(..), HsBinds(..), MonoBinds(..), Sig(..), StmtCtxt(..),
+ Match(..), collectMonoBinders, andMonoBinds
)
import RnHsSyn ( RenamedHsBinds, RenamedSig, RenamedMonoBinds )
-import TcHsSyn ( TcHsBinds, TcMonoBinds,
- TcIdOcc(..), TcIdBndr,
- tcIdType, zonkId
- )
+import TcHsSyn ( TcMonoBinds, TcId, zonkId, mkHsLet )
import TcMonad
-import Inst ( Inst, LIE, emptyLIE, mkLIE, plusLIE, plusLIEs, InstOrigin(..),
+import Inst ( LIE, emptyLIE, mkLIE, plusLIE, InstOrigin(..),
newDicts, tyVarsOfInst, instToId,
+ getAllFunDepsOfLIE, getIPsOfLIE, zonkFunDeps
)
-import TcEnv ( tcExtendLocalValEnv, tcExtendEnvWithPat,
- tcLookupLocalValueOK,
- newSpecPragmaId,
+import TcEnv ( tcExtendLocalValEnv,
+ newSpecPragmaId, newLocalId,
+ tcLookupTyCon,
tcGetGlobalTyVars, tcExtendGlobalTyVars
)
-import TcMatches ( tcMatchesFun )
-import TcSimplify ( tcSimplify, tcSimplifyAndCheck )
-import TcMonoType ( tcHsTcType, checkSigTyVars,
+import TcSimplify ( tcSimplify, tcSimplifyAndCheck, tcSimplifyToDicts )
+import TcImprove ( tcImprove )
+import TcMonoType ( tcHsSigType, checkSigTyVars,
TcSigInfo(..), tcTySig, maybeSig, sigCtxt
)
-import TcPat ( tcVarPat, tcPat )
+import TcPat ( tcPat )
import TcSimplify ( bindInstsOfLocalFuns )
-import TcType ( TcType, TcThetaType,
- TcTyVar,
- newTyVarTy, newTcTyVar, tcInstTcType,
- zonkTcType, zonkTcTypes, zonkTcThetaType )
+import TcType ( TcThetaType, newTyVarTy, newTyVar,
+ zonkTcTypes, zonkTcThetaType, zonkTcTyVarToTyVar
+ )
import TcUnify ( unifyTauTy, unifyTauTyLists )
-import Id ( mkUserId )
-import Var ( idType, idName, setIdInfo )
-import IdInfo ( IdInfo, noIdInfo, setInlinePragInfo, InlinePragInfo(..) )
-import Name ( Name )
-import Type ( mkTyVarTy, tyVarsOfTypes,
- splitSigmaTy, mkForAllTys, mkFunTys, getTyVar,
- mkDictTy, splitRhoTy, mkForAllTy, isUnLiftedType,
- isUnboxedType, openTypeKind,
- unboxedTypeKind, boxedTypeKind
+import CoreFVs ( idFreeTyVars )
+import Id ( mkVanillaId, setInlinePragma )
+import Var ( idType, idName )
+import IdInfo ( InlinePragInfo(..) )
+import Name ( Name, getOccName, getSrcLoc )
+import NameSet
+import Type ( mkTyVarTy, tyVarsOfTypes, mkTyConApp,
+ mkForAllTys, mkFunTys,
+ mkPredTy, mkForAllTy, isUnLiftedType,
+ isUnboxedType, unboxedTypeKind, boxedTypeKind, openTypeKind
)
-import Var ( TyVar, tyVarKind )
+import FunDeps ( tyVarFunDep, oclose )
+import Var ( tyVarKind )
import VarSet
import Bag
import Util ( isIn )
-import BasicTypes ( TopLevelFlag(..), RecFlag(..) )
-import SrcLoc ( SrcLoc )
+import Maybes ( maybeToBool )
+import BasicTypes ( TopLevelFlag(..), RecFlag(..), isNotTopLevel )
+import FiniteMap ( listToFM, lookupFM )
+import PrelNames ( ioTyConName, mainKey, hasKey )
import Outputable
\end{code}
dictionaries, which we resolve at the module level.
\begin{code}
-tcTopBindsAndThen, tcBindsAndThen
- :: (RecFlag -> TcMonoBinds s -> thing -> thing) -- Combinator
+tcTopBinds :: RenamedHsBinds -> TcM ((TcMonoBinds, TcEnv), LIE)
+tcTopBinds binds
+ = tc_binds_and_then TopLevel glue binds $
+ tcGetEnv `thenNF_Tc` \ env ->
+ returnTc ((EmptyMonoBinds, env), emptyLIE)
+ where
+ glue is_rec binds1 (binds2, thing) = (binds1 `AndMonoBinds` binds2, thing)
+
+
+tcBindsAndThen
+ :: (RecFlag -> TcMonoBinds -> thing -> thing) -- Combinator
-> RenamedHsBinds
- -> TcM s (thing, LIE s)
- -> TcM s (thing, LIE s)
+ -> TcM (thing, LIE)
+ -> TcM (thing, LIE)
-tcTopBindsAndThen = tc_binds_and_then TopLevel
-tcBindsAndThen = tc_binds_and_then NotTopLevel
+tcBindsAndThen = tc_binds_and_then NotTopLevel
tc_binds_and_then top_lvl combiner EmptyBinds do_next
= do_next
do_next
tc_binds_and_then top_lvl combiner (MonoBind bind sigs is_rec) do_next
- = fixTc (\ ~(prag_info_fn, _, _) ->
- -- This is the usual prag_info fix; the PragmaInfo field of an Id
- -- is not inspected till ages later in the compiler, so there
- -- should be no black-hole problems here.
-
- -- TYPECHECK THE SIGNATURES
+ = -- TYPECHECK THE SIGNATURES
mapTc tcTySig [sig | sig@(Sig name _ _) <- sigs] `thenTc` \ tc_ty_sigs ->
- tcBindWithSigs top_lvl bind
- tc_ty_sigs is_rec prag_info_fn `thenTc` \ (poly_binds, poly_lie, poly_ids) ->
+ tcBindWithSigs top_lvl bind tc_ty_sigs
+ sigs is_rec `thenTc` \ (poly_binds, poly_lie, poly_ids) ->
-- Extend the environment to bind the new polymorphic Ids
- tcExtendLocalValEnv (map idName poly_ids) poly_ids $
+ tcExtendLocalValEnv [(idName poly_id, poly_id) | poly_id <- poly_ids] $
-- Build bindings and IdInfos corresponding to user pragmas
- tcPragmaSigs sigs `thenTc` \ (prag_info_fn, prag_binds, prag_lie) ->
+ tcSpecSigs sigs `thenTc` \ (prag_binds, prag_lie) ->
-- Now do whatever happens next, in the augmented envt
do_next `thenTc` \ (thing, thing_lie) ->
-- All the top level things are rec'd together anyway, so it's fine to
-- leave them to the tcSimplifyTop, and quite a bit faster too
(TopLevel, _)
- -> returnTc (prag_info_fn,
- combiner Recursive (poly_binds `andMonoBinds` prag_binds) thing,
+ -> returnTc (combiner Recursive (poly_binds `andMonoBinds` prag_binds) thing,
thing_lie `plusLIE` prag_lie `plusLIE` poly_lie)
(NotTopLevel, NonRecursive)
poly_ids `thenTc` \ (thing_lie', lie_binds) ->
returnTc (
- prag_info_fn,
combiner NonRecursive poly_binds $
combiner NonRecursive prag_binds $
combiner Recursive lie_binds $
poly_ids `thenTc` \ (final_lie, lie_binds) ->
returnTc (
- prag_info_fn,
combiner Recursive (
poly_binds `andMonoBinds`
lie_binds `andMonoBinds`
prag_binds) thing,
final_lie
- )
- ) `thenTc` \ (_, thing, lie) ->
- returnTc (thing, lie)
+ )
\end{code}
An aside. The original version of @tcBindsAndThen@ which lacks a
\begin{pseudocode}
% tcBindsAndThen
% :: RenamedHsBinds
-% -> TcM s (thing, LIE s, thing_ty))
-% -> TcM s ((TcHsBinds s, thing), LIE s, thing_ty)
+% -> TcM (thing, LIE, thing_ty))
+% -> TcM ((TcHsBinds, thing), LIE, thing_ty)
%
% tcBindsAndThen EmptyBinds do_next
% = do_next `thenTc` \ (thing, lie, thing_ty) ->
tcBindWithSigs
:: TopLevelFlag
-> RenamedMonoBinds
- -> [TcSigInfo s]
+ -> [TcSigInfo]
+ -> [RenamedSig] -- Used solely to get INLINE, NOINLINE sigs
-> RecFlag
- -> (Name -> IdInfo)
- -> TcM s (TcMonoBinds s, LIE s, [TcIdBndr s])
+ -> TcM (TcMonoBinds, LIE, [TcId])
-tcBindWithSigs top_lvl mbind tc_ty_sigs is_rec prag_info_fn
+tcBindWithSigs top_lvl mbind tc_ty_sigs inline_sigs is_rec
= recoverTc (
-- If typechecking the binds fails, then return with each
-- signature-less binder given type (forall a.a), to minimise subsequent
-- error messages
- newTcTyVar boxedTypeKind `thenNF_Tc` \ alpha_tv ->
+ newTyVar boxedTypeKind `thenNF_Tc` \ alpha_tv ->
let
forall_a_a = mkForAllTy alpha_tv (mkTyVarTy alpha_tv)
- binder_names = map fst (bagToList (collectMonoBinders mbind))
+ 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 -> mkUserId name forall_a_a -- No signature
+ Nothing -> mkVanillaId name forall_a_a -- No signature
in
returnTc (EmptyMonoBinds, emptyLIE, poly_ids)
) $
-- TYPECHECK THE BINDINGS
- tcMonoBinds mbind tc_ty_sigs is_rec `thenTc` \ (mbind', lie_req, binder_names, mono_ids) ->
-
- let
- mono_id_tys = map idType mono_ids
- in
+ tcMonoBinds mbind tc_ty_sigs is_rec `thenTc` \ (mbind', lie_req, binder_names, mono_ids) ->
-- CHECK THAT THE SIGNATURES MATCH
-- (must do this before getTyVarsToGen)
- checkSigMatch tc_ty_sigs `thenTc` \ (sig_theta, lie_avail) ->
+ checkSigMatch top_lvl binder_names mono_ids tc_ty_sigs `thenTc` \ maybe_sig_theta ->
+
+ -- IMPROVE the LIE
+ -- Force any unifications dictated by functional dependencies.
+ -- Because unification may happen, it's important that this step
+ -- come before:
+ -- - computing vars over which to quantify
+ -- - zonking the generalized type vars
+ let lie_avail = case maybe_sig_theta of
+ Nothing -> emptyLIE
+ Just (_, la) -> la
+ lie_avail_req = lie_avail `plusLIE` lie_req in
+ tcImprove lie_avail_req `thenTc_`
-- COMPUTE VARIABLES OVER WHICH TO QUANTIFY, namely tyvars_to_gen
-- The tyvars_not_to_gen are free in the environment, and hence
-- candidates for generalisation, but sometimes the monomorphism
-- restriction means we can't generalise them nevertheless
+ let
+ mono_id_tys = map idType mono_ids
+ in
getTyVarsToGen is_unrestricted mono_id_tys lie_req `thenNF_Tc` \ (tyvars_not_to_gen, tyvars_to_gen) ->
- -- DEAL WITH TYPE VARIABLE KINDS
- -- **** This step can do unification => keep other zonking after this ****
- mapTc defaultUncommittedTyVar (varSetElems tyvars_to_gen) `thenTc` \ real_tyvars_to_gen_list ->
+ -- Finally, zonk the generalised type variables to real TyVars
+ -- This commits any unbound kind variables to boxed kind
+ -- I'm a little worried that such a kind variable might be
+ -- free in the environment, but I don't think it's possible for
+ -- this to happen when the type variable is not free in the envt
+ -- (which it isn't). SLPJ Nov 98
+ mapTc zonkTcTyVarToTyVar (varSetElems tyvars_to_gen) `thenTc` \ real_tyvars_to_gen_list ->
let
real_tyvars_to_gen = mkVarSet real_tyvars_to_gen_list
-- It's important that the final list
-- SIMPLIFY THE LIE
tcExtendGlobalTyVars tyvars_not_to_gen (
- if null real_tyvars_to_gen_list then
- -- No polymorphism, so no need to simplify context
+ let ips = getIPsOfLIE lie_avail_req in
+ if null real_tyvars_to_gen_list && (null ips || not is_unrestricted) then
+ -- No polymorphism, and no IPs, so no need to simplify context
returnTc (lie_req, EmptyMonoBinds, [])
else
- if null tc_ty_sigs then
+ case maybe_sig_theta of
+ Nothing ->
-- No signatures, so just simplify the lie
-- NB: no signatures => no polymorphic recursion, so no
-- need to use lie_avail (which will be empty anyway)
tcSimplify (text "tcBinds1" <+> ppr binder_names)
- top_lvl real_tyvars_to_gen lie_req `thenTc` \ (lie_free, dict_binds, lie_bound) ->
+ real_tyvars_to_gen lie_req `thenTc` \ (lie_free, dict_binds, lie_bound) ->
returnTc (lie_free, dict_binds, map instToId (bagToList lie_bound))
- else
+ Just (sig_theta, lie_avail) ->
+ -- There are signatures, and their context is sig_theta
+ -- Furthermore, lie_avail is an LIE containing the 'method insts'
+ -- for the things bound here
+
zonkTcThetaType sig_theta `thenNF_Tc` \ sig_theta' ->
newDicts SignatureOrigin sig_theta' `thenNF_Tc` \ (dicts_sig, dict_ids) ->
-- It's important that sig_theta is zonked, because
(if any isUnLiftedType zonked_mono_id_types then
-- Unlifted bindings must be non-recursive,
-- not top level, and non-polymorphic
- checkTc (case top_lvl of {TopLevel -> False; NotTopLevel -> True})
+ checkTc (isNotTopLevel top_lvl)
(unliftedBindErr "Top-level" mbind) `thenTc_`
checkTc (case is_rec of {Recursive -> False; NonRecursive -> True})
(unliftedBindErr "Recursive" mbind) `thenTc_`
mapNF_Tc zonkId mono_ids `thenNF_Tc` \ zonked_mono_ids ->
let
exports = zipWith mk_export binder_names zonked_mono_ids
- dict_tys = map tcIdType dicts_bound
+ dict_tys = map idType dicts_bound
+
+ inlines = mkNameSet [name | InlineSig name _ loc <- inline_sigs]
+ no_inlines = listToFM ([(name, IMustNotBeINLINEd False phase) | NoInlineSig name phase loc <- inline_sigs] ++
+ [(name, IMustNotBeINLINEd True phase) | InlineSig name phase loc <- inline_sigs, maybeToBool phase])
+ -- "INLINE n foo" means inline foo, but not until at least phase n
+ -- "NOINLINE n foo" means don't inline foo until at least phase n, and even
+ -- then only if it is small enough etc.
+ -- "NOINLINE foo" means don't inline foo ever, which we signal with a (IMustNotBeINLINEd Nothing)
+ -- See comments in CoreUnfold.blackListed for the Authorised Version
mk_export binder_name zonked_mono_id
= (tyvars,
- TcId (setIdInfo poly_id (prag_info_fn binder_name)),
- TcId zonked_mono_id)
+ attachNoInlinePrag no_inlines poly_id,
+ zonked_mono_id)
where
(tyvars, poly_id) =
case maybeSig tc_ty_sigs binder_name of
(sig_tyvars, sig_poly_id)
Nothing -> (real_tyvars_to_gen_list, new_poly_id)
- new_poly_id = mkUserId binder_name poly_ty
+ new_poly_id = mkVanillaId binder_name poly_ty
poly_ty = mkForAllTys real_tyvars_to_gen_list
$ mkFunTys dict_tys
$ idType (zonked_mono_id)
-- at all.
pat_binders :: [Name]
- pat_binders = map fst $ bagToList $ collectMonoBinders $
- (justPatBindings mbind EmptyMonoBinds)
+ pat_binders = collectMonoBinders (justPatBindings mbind EmptyMonoBinds)
in
-- CHECK FOR UNBOXED BINDERS IN PATTERN BINDINGS
mapTc (\id -> checkTc (not (idName id `elem` pat_binders
-- BUILD RESULTS
returnTc (
+ -- pprTrace "binding.." (ppr ((dicts_bound, dict_binds), exports, [idType poly_id | (_, poly_id, _) <- exports])) $
AbsBinds real_tyvars_to_gen_list
dicts_bound
exports
+ inlines
(dict_binds `andMonoBinds` mbind'),
lie_free,
- [poly_id | (_, TcId poly_id, _) <- exports]
+ [poly_id | (_, poly_id, _) <- exports]
)
where
tysig_names = [name | (TySigInfo name _ _ _ _ _ _ _) <- tc_ty_sigs]
justPatBindings (AndMonoBinds b1 b2) binds =
justPatBindings b1 (justPatBindings b2 binds)
justPatBindings other_bind binds = binds
+
+attachNoInlinePrag no_inlines bndr
+ = case lookupFM no_inlines (idName bndr) of
+ Just prag -> bndr `setInlinePragma` prag
+ Nothing -> bndr
\end{code}
Polymorphic recursion
%* *
%************************************************************************
-@getTyVarsToGen@ decides what type variables generalise over.
+@getTyVarsToGen@ decides what type variables to generalise over.
For a "restricted group" -- see the monomorphism restriction
for a definition -- we bind no dictionaries, and
= tcGetGlobalTyVars `thenNF_Tc` \ free_tyvars ->
zonkTcTypes mono_id_tys `thenNF_Tc` \ zonked_mono_id_tys ->
let
- tyvars_to_gen = tyVarsOfTypes zonked_mono_id_tys `minusVarSet` free_tyvars
+ body_tyvars = tyVarsOfTypes zonked_mono_id_tys `minusVarSet` free_tyvars
+ fds = getAllFunDepsOfLIE lie
in
if is_unrestricted
then
- returnNF_Tc (emptyVarSet, tyvars_to_gen)
+ -- We need to augment the type variables that appear explicitly in
+ -- the type by those that are determined by the functional dependencies.
+ -- e.g. suppose our type is C a b => a -> a
+ -- with the fun-dep a->b
+ -- Then we should generalise over b too; otherwise it will be
+ -- reported as ambiguous.
+ zonkFunDeps fds `thenNF_Tc` \ fds' ->
+ let tvFundep = tyVarFunDep fds'
+ extended_tyvars = oclose tvFundep body_tyvars
+ in
+ returnNF_Tc (emptyVarSet, extended_tyvars)
else
-- This recover and discard-errs is to avoid duplicate error
-- messages; this, after all, is an "extra" call to tcSimplify
- recoverNF_Tc (returnNF_Tc (emptyVarSet, tyvars_to_gen)) $
+ recoverNF_Tc (returnNF_Tc (emptyVarSet, body_tyvars)) $
discardErrsTc $
- tcSimplify (text "getTVG") NotTopLevel tyvars_to_gen lie `thenTc` \ (_, _, constrained_dicts) ->
+ tcSimplify (text "getTVG") body_tyvars lie `thenTc` \ (_, _, constrained_dicts) ->
let
-- ASSERT: dicts_sig is already zonked!
constrained_tyvars = foldrBag (unionVarSet . tyVarsOfInst) emptyVarSet constrained_dicts
- reduced_tyvars_to_gen = tyvars_to_gen `minusVarSet` constrained_tyvars
+ reduced_tyvars_to_gen = body_tyvars `minusVarSet` constrained_tyvars
in
returnTc (constrained_tyvars, reduced_tyvars_to_gen)
\end{code}
is_elem v vs = isIn "isUnResMono" v vs
-isUnRestrictedGroup sigs (PatMonoBind (VarPatIn v) _ _) = v `is_elem` sigs
-isUnRestrictedGroup sigs (PatMonoBind other _ _) = False
+isUnRestrictedGroup sigs (PatMonoBind other _ _) = False
isUnRestrictedGroup sigs (VarMonoBind v _) = v `is_elem` sigs
-isUnRestrictedGroup sigs (FunMonoBind _ _ _ _) = True
+isUnRestrictedGroup sigs (FunMonoBind v _ matches _) = any isUnRestrictedMatch matches ||
+ v `is_elem` sigs
isUnRestrictedGroup sigs (AndMonoBinds mb1 mb2) = isUnRestrictedGroup sigs mb1 &&
isUnRestrictedGroup sigs mb2
isUnRestrictedGroup sigs EmptyMonoBinds = True
-\end{code}
-@defaultUncommittedTyVar@ checks for generalisation over unboxed
-types, and defaults any TypeKind TyVars to BoxedTypeKind.
-
-\begin{code}
-defaultUncommittedTyVar tyvar
- | tyVarKind tyvar == openTypeKind
- = newTcTyVar boxedTypeKind `thenNF_Tc` \ boxed_tyvar ->
- unifyTauTy (mkTyVarTy tyvar) (mkTyVarTy boxed_tyvar) `thenTc_`
- returnTc boxed_tyvar
-
- | otherwise
- = returnTc tyvar
+isUnRestrictedMatch (Match _ [] Nothing _) = False -- No args, no signature
+isUnRestrictedMatch other = True -- Some args or a signature
\end{code}
\begin{code}
tcMonoBinds :: RenamedMonoBinds
- -> [TcSigInfo s]
+ -> [TcSigInfo]
-> RecFlag
- -> TcM s (TcMonoBinds s,
- LIE s, -- LIE required
+ -> TcM (TcMonoBinds,
+ LIE, -- LIE required
[Name], -- Bound names
- [TcIdBndr s]) -- Corresponding monomorphic bound things
+ [TcId]) -- Corresponding monomorphic bound things
tcMonoBinds mbinds tc_ty_sigs is_rec
= tc_mb_pats mbinds `thenTc` \ (complete_it, lie_req_pat, tvs, ids, lie_avail) ->
let
- tv_list = bagToList tvs
- (names, mono_ids) = unzip (bagToList ids)
+ id_list = bagToList ids
+ (names, mono_ids) = unzip id_list
+
+ -- This last defn is the key one:
+ -- extend the val envt with bindings for the
+ -- things bound in this group, overriding the monomorphic
+ -- ids with the polymorphic ones from the pattern
+ extra_val_env = case is_rec of
+ Recursive -> map mk_bind id_list
+ NonRecursive -> []
in
-- Don't know how to deal with pattern-bound existentials yet
checkTc (isEmptyBag tvs && isEmptyBag lie_avail)
(existentialExplode mbinds) `thenTc_`
- -- *Before* checking the RHSs, but *after* checking *all* the patterns,
+ -- *Before* checking the RHSs, but *after* checking *all* the patterns,
-- extend the envt with bindings for all the bound ids;
-- and *then* override with the polymorphic Ids from the signatures
-- That is the whole point of the "complete_it" stuff.
- tcExtendEnvWithPat ids (tcExtendEnvWithPat sig_ids
- complete_it
- ) `thenTc` \ (mbinds', lie_req_rhss) ->
+ --
+ -- There's a further wrinkle: we have to delay extending the environment
+ -- until after we've dealt with any pattern-bound signature type variables
+ -- Consider f (x::a) = ...f...
+ -- We're going to check that a isn't unified with anything in the envt,
+ -- so f itself had better not be! So we pass the envt binding f into
+ -- complete_it, which extends the actual envt in TcMatches.tcMatch, after
+ -- dealing with the signature tyvars
+
+ complete_it extra_val_env `thenTc` \ (mbinds', lie_req_rhss) ->
+
returnTc (mbinds', lie_req_pat `plusLIE` lie_req_rhss, names, mono_ids)
where
- sig_fn name = case maybeSig tc_ty_sigs name of
- Nothing -> Nothing
- Just (TySigInfo _ _ _ _ _ mono_id _ _) -> Just mono_id
- sig_ids = listToBag [(name,poly_id) | TySigInfo name poly_id _ _ _ _ _ _ <- tc_ty_sigs]
+ -- This function is used when dealing with a LHS binder; we make a monomorphic
+ -- version of the Id. We check for type signatures
+ tc_pat_bndr name pat_ty
+ = case maybeSig tc_ty_sigs name of
+ Nothing
+ -> newLocalId (getOccName name) pat_ty (getSrcLoc name)
- kind = case is_rec of
- Recursive -> boxedTypeKind -- Recursive, so no unboxed types
- NonRecursive -> openTypeKind -- Non-recursive, so we permit unboxed types
+ Just (TySigInfo _ _ _ _ _ mono_id _ _)
+ -> tcAddSrcLoc (getSrcLoc name) $
+ unifyTauTy (idType mono_id) pat_ty `thenTc_`
+ returnTc mono_id
+
+ mk_bind (name, mono_id) = case maybeSig tc_ty_sigs name of
+ Nothing -> (name, mono_id)
+ Just (TySigInfo name poly_id _ _ _ _ _ _) -> (name, poly_id)
tc_mb_pats EmptyMonoBinds
- = returnTc (returnTc (EmptyMonoBinds, emptyLIE), emptyLIE, emptyBag, emptyBag, emptyLIE)
+ = returnTc (\ xve -> returnTc (EmptyMonoBinds, emptyLIE), emptyLIE, emptyBag, emptyBag, emptyLIE)
tc_mb_pats (AndMonoBinds mb1 mb2)
= tc_mb_pats mb1 `thenTc` \ (complete_it1, lie_req1, tvs1, ids1, lie_avail1) ->
tc_mb_pats mb2 `thenTc` \ (complete_it2, lie_req2, tvs2, ids2, lie_avail2) ->
let
- complete_it = complete_it1 `thenTc` \ (mb1', lie1) ->
- complete_it2 `thenTc` \ (mb2', lie2) ->
- returnTc (AndMonoBinds mb1' mb2', lie1 `plusLIE` lie2)
+ complete_it xve = complete_it1 xve `thenTc` \ (mb1', lie1) ->
+ complete_it2 xve `thenTc` \ (mb2', lie2) ->
+ returnTc (AndMonoBinds mb1' mb2', lie1 `plusLIE` lie2)
in
returnTc (complete_it,
lie_req1 `plusLIE` lie_req2,
lie_avail1 `plusLIE` lie_avail2)
tc_mb_pats (FunMonoBind name inf matches locn)
- = newTyVarTy boxedTypeKind `thenNF_Tc` \ pat_ty ->
- tcVarPat sig_fn name pat_ty `thenTc` \ bndr_id ->
+ = newTyVarTy kind `thenNF_Tc` \ bndr_ty ->
+ tc_pat_bndr name bndr_ty `thenTc` \ bndr_id ->
let
- complete_it = tcAddSrcLoc locn $
- tcMatchesFun name pat_ty matches `thenTc` \ (matches', lie) ->
- returnTc (FunMonoBind (TcId bndr_id) inf matches' locn, lie)
+ complete_it xve = tcAddSrcLoc locn $
+ 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)
- tc_mb_pats bind@(PatMonoBind pat grhss_and_binds locn)
+ tc_mb_pats bind@(PatMonoBind pat grhss locn)
= tcAddSrcLoc locn $
- newTyVarTy kind `thenNF_Tc` \ pat_ty ->
- tcPat sig_fn pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
+ newTyVarTy kind `thenNF_Tc` \ pat_ty ->
+
+ -- Now typecheck the pattern
+ -- We don't support binding fresh type variables in the
+ -- pattern of a pattern binding. For example, this is illegal:
+ -- (x::a, y::b) = e
+ -- whereas this is ok
+ -- (x::Int, y::Bool) = e
+ --
+ -- We don't check explicitly for this problem. Instead, we simply
+ -- type check the pattern with tcPat. If the pattern mentions any
+ -- fresh tyvars we simply get an out-of-scope type variable error
+ tcPat tc_pat_bndr pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
let
- complete_it = tcAddSrcLoc locn $
- tcAddErrCtxt (patMonoBindsCtxt bind) $
- tcGRHSsAndBinds grhss_and_binds pat_ty PatBindRhs `thenTc` \ (grhss_and_binds', lie) ->
- returnTc (PatMonoBind pat' grhss_and_binds' locn, lie)
+ complete_it xve = tcAddSrcLoc locn $
+ tcAddErrCtxt (patMonoBindsCtxt bind) $
+ tcExtendLocalValEnv xve $
+ tcGRHSs grhss pat_ty PatBindRhs `thenTc` \ (grhss', lie) ->
+ returnTc (PatMonoBind pat' grhss' locn, lie)
in
returnTc (complete_it, lie_req, tvs, ids, lie_avail)
+
+ -- Figure out the appropriate kind for the pattern,
+ -- and generate a suitable type variable
+ kind = case is_rec of
+ Recursive -> boxedTypeKind -- Recursive, so no unboxed types
+ NonRecursive -> openTypeKind -- Non-recursive, so we permit unboxed types
\end{code}
%************************************************************************
now (ToDo).
\begin{code}
-checkSigMatch []
- = returnTc (error "checkSigMatch", emptyLIE)
+checkSigMatch :: TopLevelFlag -> [Name] -> [TcId] -> [TcSigInfo] -> TcM (Maybe (TcThetaType, LIE))
+checkSigMatch top_lvl binder_names mono_ids sigs
+ | main_bound_here
+ = -- First unify the main_id with IO t, for any old t
+ tcSetErrCtxt mainTyCheckCtxt (
+ tcLookupTyCon ioTyConName `thenTc` \ ioTyCon ->
+ newTyVarTy boxedTypeKind `thenNF_Tc` \ t_tv ->
+ unifyTauTy ((mkTyConApp ioTyCon [t_tv]))
+ (idType main_mono_id)
+ ) `thenTc_`
+
+ -- Now check the signatures
+ -- Must do this after the unification with IO t,
+ -- in case of a silly signature like
+ -- main :: forall a. a
+ -- The unification to IO t will bind the type variable 'a',
+ -- which is just waht check_one_sig looks for
+ mapTc check_one_sig sigs `thenTc_`
+ mapTc check_main_ctxt sigs `thenTc_`
+ returnTc (Just ([], emptyLIE))
+
+ | not (null sigs)
+ = mapTc check_one_sig sigs `thenTc_`
+ mapTc check_one_ctxt all_sigs_but_first `thenTc_`
+ returnTc (Just (theta1, sig_lie))
+
+ | otherwise
+ = returnTc Nothing -- No constraints from type sigs
+
+ where
+ (TySigInfo _ id1 _ theta1 _ _ _ _ : all_sigs_but_first) = sigs
-checkSigMatch tc_ty_sigs@( sig1@(TySigInfo _ id1 _ theta1 _ _ _ _) : all_sigs_but_first )
- = -- CHECK THAT THE SIGNATURE TYVARS AND TAU_TYPES ARE OK
+ sig1_dict_tys = mk_dict_tys theta1
+ n_sig1_dict_tys = length sig1_dict_tys
+ sig_lie = mkLIE (concat [insts | TySigInfo _ _ _ _ _ _ insts _ <- sigs])
+
+ maybe_main = find_main top_lvl binder_names mono_ids
+ main_bound_here = maybeToBool maybe_main
+ Just main_mono_id = maybe_main
+
+ -- CHECK THAT THE SIGNATURE TYVARS AND TAU_TYPES ARE OK
-- Doesn't affect substitution
- mapTc check_one_sig tc_ty_sigs `thenTc_`
+ check_one_sig (TySigInfo _ id sig_tyvars sig_theta sig_tau _ _ src_loc)
+ = tcAddSrcLoc src_loc $
+ tcAddErrCtxtM (sigCtxt (sig_msg id) sig_tyvars sig_theta sig_tau) $
+ checkSigTyVars sig_tyvars (idFreeTyVars id)
+
-- CHECK THAT ALL THE SIGNATURE CONTEXTS ARE UNIFIABLE
-- The type signatures on a mutually-recursive group of definitions
-- We unify them because, with polymorphic recursion, their types
-- might not otherwise be related. This is a rather subtle issue.
-- ToDo: amplify
- mapTc check_one_cxt all_sigs_but_first `thenTc_`
-
- returnTc (theta1, sig_lie)
- where
- sig1_dict_tys = mk_dict_tys theta1
- n_sig1_dict_tys = length sig1_dict_tys
- sig_lie = mkLIE [inst | TySigInfo _ _ _ _ _ _ inst _ <- tc_ty_sigs]
-
- check_one_cxt sig@(TySigInfo _ id _ theta _ _ _ src_loc)
+ check_one_ctxt sig@(TySigInfo _ id _ theta _ _ _ src_loc)
= tcAddSrcLoc src_loc $
tcAddErrCtxt (sigContextsCtxt id1 id) $
checkTc (length this_sig_dict_tys == n_sig1_dict_tys)
where
this_sig_dict_tys = mk_dict_tys theta
- check_one_sig (TySigInfo _ id sig_tyvars _ sig_tau _ _ src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxtM (sigCtxt (quotes (ppr id)) sig_tau) $
- checkSigTyVars sig_tyvars
+ -- CHECK THAT FOR A GROUP INVOLVING Main.main, all
+ -- the signature contexts are empty (what a bore)
+ check_main_ctxt sig@(TySigInfo _ id _ theta _ _ _ src_loc)
+ = tcAddSrcLoc src_loc $
+ checkTc (null theta) (mainContextsErr id)
+
+ mk_dict_tys theta = map mkPredTy theta
- mk_dict_tys theta = [mkDictTy c ts | (c,ts) <- theta]
+ sig_msg id = ptext SLIT("When checking the type signature for") <+> quotes (ppr id)
+
+ -- Search for Main.main in the binder_names, return corresponding mono_id
+ find_main NotTopLevel binder_names mono_ids = Nothing
+ find_main TopLevel binder_names mono_ids = go binder_names mono_ids
+ go [] [] = Nothing
+ go (n:ns) (m:ms) | n `hasKey` mainKey = Just m
+ | otherwise = go ns ms
\end{code}
%* *
%************************************************************************
-
-@tcPragmaSigs@ munches up the "signatures" that arise through *user*
+@tcSpecSigs@ munches up the specialisation "signatures" that arise through *user*
pragmas. It is convenient for them to appear in the @[RenamedSig]@
part of a binding because then the same machinery can be used for
moving them into place as is done for type signatures.
-\begin{code}
-tcPragmaSigs :: [RenamedSig] -- The pragma signatures
- -> TcM s (Name -> IdInfo, -- Maps name to the appropriate IdInfo
- TcMonoBinds s,
- LIE s)
-
-tcPragmaSigs sigs
- = mapAndUnzip3Tc tcPragmaSig sigs `thenTc` \ (maybe_info_modifiers, binds, lies) ->
- let
- prag_fn name = foldr ($) noIdInfo [f | Just (n,f) <- maybe_info_modifiers, n==name]
- in
- returnTc (prag_fn, andMonoBindList binds, plusLIEs lies)
-\end{code}
+They look like this:
-The interesting case is for SPECIALISE pragmas. There are two forms.
-Here's the first form:
\begin{verbatim}
f :: Ord a => [a] -> b -> b
{-# SPECIALIZE f :: [Int] -> b -> b #-}
Int, and will create a specialisation for @f@. After that, the
binding for @f*@ can be discarded.
-The second form is this:
-\begin{verbatim}
- f :: Ord a => [a] -> b -> b
- {-# SPECIALIZE f :: [Int] -> b -> b = g #-}
-\end{verbatim}
-
-Here @g@ is specified as a function that implements the specialised
-version of @f@. Suppose that g has type (a->b->b); that is, g's type
-is more general than that required. For this we generate
-\begin{verbatim}
- f@Int = /\b -> g Int b
- f* = f@Int
-\end{verbatim}
-
-Here @f@@Int@ is a SpecId, the specialised version of @f@. It inherits
-f's export status etc. @f*@ is a SpecPragmaId, as before, which just serves
-to prevent @f@@Int@ from being discarded prematurely. After specialisation,
-if @f@@Int@ is going to be used at all it will be used explicitly, so the simplifier can
-discard the f* binding.
-
-Actually, there is really only point in giving a SPECIALISE pragma on exported things,
-and the simplifer won't discard SpecIds for exporte things anyway, so maybe this is
-a bit of overkill.
+We used to have a form
+ {-# SPECIALISE f :: <type> = g #-}
+which promised that g implemented f at <type>, but we do that with
+a RULE now:
+ {-# SPECIALISE (f::<type) = g #-}
\begin{code}
-tcPragmaSig :: RenamedSig -> TcM s (Maybe (Name, IdInfo -> IdInfo), TcMonoBinds s, LIE s)
-tcPragmaSig (Sig _ _ _) = returnTc (Nothing, EmptyMonoBinds, emptyLIE)
-tcPragmaSig (SpecInstSig _ _) = returnTc (Nothing, EmptyMonoBinds, emptyLIE)
-
-tcPragmaSig (InlineSig name loc)
- = returnTc (Just (name, setInlinePragInfo IWantToBeINLINEd), EmptyMonoBinds, emptyLIE)
-
-tcPragmaSig (NoInlineSig name loc)
- = returnTc (Just (name, setInlinePragInfo IMustNotBeINLINEd), EmptyMonoBinds, emptyLIE)
-
-tcPragmaSig (SpecSig name poly_ty maybe_spec_name src_loc)
+tcSpecSigs :: [RenamedSig] -> TcM (TcMonoBinds, LIE)
+tcSpecSigs (SpecSig name poly_ty src_loc : sigs)
= -- SPECIALISE f :: forall b. theta => tau = g
tcAddSrcLoc src_loc $
tcAddErrCtxt (valSpecSigCtxt name poly_ty) $
-- Get and instantiate its alleged specialised type
- tcHsTcType poly_ty `thenTc` \ sig_ty ->
+ tcHsSigType poly_ty `thenTc` \ sig_ty ->
-- Check that f has a more general type, and build a RHS for
-- the spec-pragma-id at the same time
tcExpr (HsVar name) sig_ty `thenTc` \ (spec_expr, spec_lie) ->
- case maybe_spec_name of
- Nothing -> -- Just specialise "f" by building a SpecPragmaId binding
- -- It is the thing that makes sure we don't prematurely
- -- dead-code-eliminate the binding we are really interested in.
- newSpecPragmaId name sig_ty `thenNF_Tc` \ spec_id ->
- returnTc (Nothing, VarMonoBind (TcId spec_id) spec_expr, spec_lie)
-
- Just g_name -> -- Don't create a SpecPragmaId. Instead add some suitable IdIfo
-
- panic "Can't handle SPECIALISE with a '= g' part"
-
- {- Not yet. Because we're still in the TcType world we
- can't really add to the SpecEnv of the Id. Instead we have to
- record the information in a different sort of Sig, and add it to
- the IdInfo after zonking.
-
- For now we just leave out this case
-
- -- Get the type of f, and find out what types
- -- f has to be instantiated at to give the signature type
- tcLookupLocalValueOK "tcPragmaSig" name `thenNF_Tc` \ f_id ->
- tcInstTcType (idType f_id) `thenNF_Tc` \ (f_tyvars, f_rho) ->
-
- let
- (sig_tyvars, sig_theta, sig_tau) = splitSigmaTy sig_ty
- (f_theta, f_tau) = splitRhoTy f_rho
- sig_tyvar_set = mkVarSet sig_tyvars
- in
- unifyTauTy sig_tau f_tau `thenTc_`
-
- tcPolyExpr str (HsVar g_name) (mkSigmaTy sig_tyvars f_theta sig_tau) `thenTc` \ (_, _,
- -}
-
-tcPragmaSig other = pprTrace "tcPragmaSig: ignoring" (ppr other) $
- returnTc (Nothing, EmptyMonoBinds, emptyLIE)
+ -- Squeeze out any Methods (see comments with tcSimplifyToDicts)
+ tcSimplifyToDicts spec_lie `thenTc` \ (spec_lie1, spec_binds) ->
+
+ -- Just specialise "f" by building a SpecPragmaId binding
+ -- It is the thing that makes sure we don't prematurely
+ -- dead-code-eliminate the binding we are really interested in.
+ newSpecPragmaId name sig_ty `thenNF_Tc` \ spec_id ->
+
+ -- Do the rest and combine
+ tcSpecSigs sigs `thenTc` \ (binds_rest, lie_rest) ->
+ returnTc (binds_rest `andMonoBinds` VarMonoBind spec_id (mkHsLet spec_binds spec_expr),
+ lie_rest `plusLIE` spec_lie1)
+
+tcSpecSigs (other_sig : sigs) = tcSpecSigs sigs
+tcSpecSigs [] = returnTc (EmptyMonoBinds, emptyLIE)
\end{code}
-----------------------------------------------
valSpecSigCtxt v ty
= sep [ptext SLIT("In a SPECIALIZE pragma for a value:"),
- nest 4 (ppr v <+> ptext SLIT(" ::") <+> ppr ty)]
-
------------------------------------------------
-notAsPolyAsSigErr sig_tau mono_tyvars
- = hang (ptext SLIT("A type signature is more polymorphic than the inferred type"))
- 4 (vcat [text "Can't for-all the type variable(s)" <+>
- pprQuotedList mono_tyvars,
- text "in the type" <+> quotes (ppr sig_tau)
- ])
-
------------------------------------------------
-badMatchErr sig_ty inferred_ty
- = hang (ptext SLIT("Type signature doesn't match inferred type"))
- 4 (vcat [hang (ptext SLIT("Signature:")) 4 (ppr sig_ty),
- hang (ptext SLIT("Inferred :")) 4 (ppr inferred_ty)
- ])
+ nest 4 (ppr v <+> dcolon <+> ppr ty)]
-----------------------------------------------
unboxedPatBindErr id
-----------------------------------------------
sigContextsErr
= ptext SLIT("Mismatched contexts")
+
sigContextsCtxt s1 s2
= hang (hsep [ptext SLIT("When matching the contexts of the signatures for"),
quotes (ppr s1), ptext SLIT("and"), quotes (ppr s2)])
4 (ptext SLIT("(the signature contexts in a mutually recursive group should all be identical)"))
+mainContextsErr id
+ | id `hasKey` mainKey = ptext SLIT("Main.main cannot be overloaded")
+ | otherwise
+ = quotes (ppr id) <+> ptext SLIT("cannot be overloaded") <> char ',' <> -- sigh; workaround for cpp's inability to deal
+ ptext SLIT("because it is mutually recursive with Main.main") -- with commas inside SLIT strings.
+
+mainTyCheckCtxt
+ = hsep [ptext SLIT("When checking that"), quotes (ptext SLIT("main")),
+ ptext SLIT("has the required type")]
+
-----------------------------------------------
unliftedBindErr flavour mbind
= hang (text flavour <+> ptext SLIT("bindings for unlifted types aren't allowed"))
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