\begin{code}
module TcBinds ( tcLocalBinds, tcTopBinds,
tcHsBootSigs, tcPolyBinds,
- PragFun, tcPrags, mkPragFun,
+ PragFun, tcSpecPrags, mkPragFun,
TcSigInfo(..), SigFun, mkSigFun,
badBootDeclErr ) where
import TcPat
import TcMType
import TcType
+import RnBinds( misplacedSigErr )
import Coercion
import TysPrim
import Id
import Data.List( partition )
import Control.Monad
+
+#include "HsVersions.h"
\end{code}
dictionaries, which we resolve at the module level.
\begin{code}
-tcTopBinds :: HsValBinds Name -> TcM (LHsBinds TcId, TcLclEnv)
+tcTopBinds :: HsValBinds Name
+ -> TcM ( LHsBinds TcId -- Typechecked bindings
+ , [LTcSpecPrag] -- SPECIALISE prags for imported Ids
+ , TcLclEnv) -- Augmented environment
+
-- Note: returning the TcLclEnv is more than we really
-- want. The bit we care about is the local bindings
-- and the free type variables thereof
tcTopBinds binds
- = do { (ValBindsOut prs _, env) <- tcValBinds TopLevel binds getLclEnv
- ; return (foldr (unionBags . snd) emptyBag prs, env) }
+ = do { (ValBindsOut prs sigs, env) <- tcValBinds TopLevel binds getLclEnv
+ ; let binds = foldr (unionBags . snd) emptyBag prs
+ ; specs <- tcImpPrags sigs
+ ; return (binds, specs, env) }
-- The top level bindings are flattened into a giant
-- implicitly-mutually-recursive LHsBinds
-- If the binding binds ?x = E, we must now
-- discharge any ?x constraints in expr_lie
+ -- See Note [Implicit parameter untouchables]
; (ev_binds, result) <- checkConstraints (IPSkol ips)
- emptyVarSet [] -- No skolem tyvars and hence
- -- no need for envt tyvars
- given_ips $
- thing_inside
+ [] given_ips thing_inside
; return (HsIPBinds (IPBinds ip_binds' ev_binds), result) }
where
; ip_id <- newIP ip ty
; expr' <- tcMonoExpr expr ty
; return (ip_id, (IPBind (IPName ip_id) expr')) }
+\end{code}
-------------------------
+Note [Implicit parameter untouchables]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+We add the type variables in the types of the implicit parameters
+as untouchables, not so much because we really must not unify them,
+but rather because we otherwise end up with constraints like this
+ Num alpha, Implic { wanted = alpha ~ Int }
+The constraint solver solves alpha~Int by unification, but then
+doesn't float that solved constraint out (it's not an unsolved
+wanted. Result disaster: the (Num alpha) is again solved, this
+time by defaulting. No no no.
+
+However [Oct 10] this is all handled automatically by the
+untouchable-range idea.
+
+\begin{code}
tcValBinds :: TopLevelFlag
-> HsValBinds Name -> TcM thing
-> TcM (HsValBinds TcId, thing)
-- leave them to the tcSimplifyTop, and quite a bit faster too
| otherwise -- Nested case
- = do { ((binds, ids, thing), lie) <- getConstraints thing_inside
+ = do { ((binds, ids, thing), lie) <- captureConstraints thing_inside
; lie_binds <- bindLocalMethods lie ids
; return (binds, lie_binds, thing) }
-}
; let plan = decideGeneralisationPlan dflags top_lvl binder_names bind_list tc_sig_fn
; traceTc "Generalisation plan" (ppr plan)
; (binds, poly_ids) <- case plan of
- NoGen -> tcPolyNoGen tc_sig_fn prag_fn rec_group rec_tc bind_list
- InferGen mono -> tcPolyInfer top_lvl mono tc_sig_fn prag_fn rec_group rec_tc bind_list
- CheckGen sig -> tcPolyCheck sig prag_fn rec_group rec_tc bind_list
+ NoGen -> tcPolyNoGen tc_sig_fn prag_fn rec_tc bind_list
+ InferGen mono -> tcPolyInfer top_lvl mono tc_sig_fn prag_fn rec_tc bind_list
+ CheckGen sig -> tcPolyCheck sig prag_fn rec_tc bind_list
-- Check whether strict bindings are ok
-- These must be non-recursive etc, and are not generalised
-- They desugar to a case expression in the end
; checkStrictBinds top_lvl rec_group bind_list poly_ids
- -- Warn about missing signatures
- -- Do this only when we we have a type to offer
- ; warn_missing_sigs <- doptM Opt_WarnMissingSigs
- ; when (isTopLevel top_lvl && warn_missing_sigs) $
- mapM_ missingSigWarn (filter no_sig poly_ids)
-
; return (binds, poly_ids) }
where
- no_sig id = isNothing (sig_fn (idName id))
-
binder_names = collectHsBindListBinders bind_list
loc = getLoc (head bind_list)
-- TODO: location a bit awkward, but the mbinds have been
-- dependency analysed and may no longer be adjacent
+------------------
tcPolyNoGen
:: TcSigFun -> PragFun
- -> RecFlag -- Whether the group is really recursive
-> RecFlag -- Whether it's recursive after breaking
-- dependencies based on type signatures
-> [LHsBind Name]
-> TcM (LHsBinds TcId, [TcId])
-- No generalisation whatsoever
-tcPolyNoGen tc_sig_fn prag_fn rec_group rec_tc bind_list
- = do { (binds', mono_infos) <- tcMonoBinds tc_sig_fn True rec_tc bind_list
+tcPolyNoGen tc_sig_fn prag_fn rec_tc bind_list
+ = do { (binds', mono_infos) <- tcMonoBinds tc_sig_fn (LetGblBndr prag_fn)
+ rec_tc bind_list
; mono_ids' <- mapM tc_mono_info mono_infos
; return (binds', mono_ids') }
where
= do { mono_ty' <- zonkTcTypeCarefully (idType mono_id)
-- Zonk, mainly to expose unboxed types to checkStrictBinds
; let mono_id' = setIdType mono_id mono_ty'
- ; (mono_id'', _specs) <- tcPrags rec_group False False
- mono_id' (prag_fn name)
- ; return mono_id'' }
- -- NB: tcPrags generates and error message for
+ ; _specs <- tcSpecPrags mono_id' (prag_fn name)
+ ; return mono_id' }
+ -- NB: tcPrags generates error messages for
-- specialisation pragmas for non-overloaded sigs
+ -- Indeed that is why we call it here!
-- So we can safely ignore _specs
------------------
tcPolyCheck :: TcSigInfo -> PragFun
- -> RecFlag -- Whether the group is really recursive
-> RecFlag -- Whether it's recursive after breaking
-- dependencies based on type signatures
-> [LHsBind Name]
-- it has a signature,
tcPolyCheck sig@(TcSigInfo { sig_id = id, sig_tvs = tvs, sig_scoped = scoped
, sig_theta = theta, sig_loc = loc })
- prag_fn rec_group rec_tc bind_list
+ prag_fn rec_tc bind_list
= do { ev_vars <- newEvVars theta
; let skol_info = SigSkol (FunSigCtxt (idName id))
; (ev_binds, (binds', [mono_info]))
- <- checkConstraints skol_info emptyVarSet tvs ev_vars $
+ <- checkConstraints skol_info tvs ev_vars $
tcExtendTyVarEnv2 (scoped `zip` mkTyVarTys tvs) $
- tcMonoBinds (\_ -> Just sig) False rec_tc bind_list
+ tcMonoBinds (\_ -> Just sig) LetLclBndr rec_tc bind_list
- ; export <- mkExport rec_group False prag_fn tvs theta mono_info
+ ; export <- mkExport prag_fn tvs theta mono_info
; let (_, poly_id, _, _) = export
abs_bind = L loc $ AbsBinds
, abs_exports = [export], abs_binds = binds' }
; return (unitBag abs_bind, [poly_id]) }
+------------------
tcPolyInfer
:: TopLevelFlag
-> Bool -- True <=> apply the monomorphism restriction
-> TcSigFun -> PragFun
- -> RecFlag -- Whether the group is really recursive
-> RecFlag -- Whether it's recursive after breaking
-- dependencies based on type signatures
-> [LHsBind Name]
-> TcM (LHsBinds TcId, [TcId])
-tcPolyInfer top_lvl mono sig_fn prag_fn rec_group rec_tc bind_list
+tcPolyInfer top_lvl mono sig_fn prag_fn rec_tc bind_list
= do { ((binds', mono_infos), wanted)
- <- getConstraints $
- tcMonoBinds sig_fn False rec_tc bind_list
+ <- captureConstraints $
+ tcMonoBinds sig_fn LetLclBndr rec_tc bind_list
; unifyCtxts [sig | (_, Just sig, _) <- mono_infos]
; (qtvs, givens, ev_binds) <- simplifyInfer mono tau_tvs wanted
- ; exports <- mapM (mkExport rec_group (length mono_infos > 1)
- prag_fn qtvs (map evVarPred givens))
+ ; exports <- mapM (mkExport prag_fn qtvs (map evVarPred givens))
mono_infos
; let poly_ids = [poly_id | (_, poly_id, _, _) <- exports]
--------------
-mkExport :: RecFlag
- -> Bool -- More than one variable is bound, so we'll desugar to
- -- a tuple, so INLINE pragmas won't work
- -> PragFun -> [TyVar] -> TcThetaType
+mkExport :: PragFun -> [TyVar] -> TcThetaType
-> MonoBindInfo
-> TcM ([TyVar], Id, Id, TcSpecPrags)
-- mkExport generates exports with
-- Pre-condition: the inferred_tvs are already zonked
-mkExport rec_group multi_bind prag_fn inferred_tvs theta
+mkExport prag_fn inferred_tvs theta
(poly_name, mb_sig, mono_id)
= do { (tvs, poly_id) <- mk_poly_id mb_sig
-- poly_id has a zonked type
- ; (poly_id', spec_prags) <- tcPrags rec_group multi_bind (notNull theta)
- poly_id (prag_fn poly_name)
+ ; poly_id' <- addInlinePrags poly_id prag_sigs
+
+ ; spec_prags <- tcSpecPrags poly_id prag_sigs
-- tcPrags requires a zonked poly_id
; return (tvs, poly_id', mono_id, SpecPrags spec_prags) }
where
+ prag_sigs = prag_fn poly_name
poly_ty = mkSigmaTy inferred_tvs theta (idType mono_id)
mk_poly_id Nothing = do { poly_ty' <- zonkTcTypeCarefully poly_ty
get_sig _ = Nothing
add_arity (L _ n) inl_prag -- Adjust inl_sat field to match visible arity of function
- | Just ar <- lookupNameEnv ar_env n = inl_prag { inl_sat = Just ar }
+ | Just ar <- lookupNameEnv ar_env n,
+ Inline <- inl_inline inl_prag = inl_prag { inl_sat = Just ar }
+ -- add arity only for real INLINE pragmas, not INLINABLE
| otherwise = inl_prag
prag_env :: NameEnv [LSig Name]
= extendNameEnv env (unLoc id) (matchGroupArity ms)
lhsBindArity _ env = env -- PatBind/VarBind
-tcPrags :: RecFlag
- -> Bool -- True <=> AbsBinds binds more than one variable
- -> Bool -- True <=> function is overloaded
- -> Id -> [LSig Name]
- -> TcM (Id, [Located TcSpecPrag])
+------------------
+tcSpecPrags :: Id -> [LSig Name]
+ -> TcM [LTcSpecPrag]
-- Add INLINE and SPECIALSE pragmas
-- INLINE prags are added to the (polymorphic) Id directly
-- SPECIALISE prags are passed to the desugarer via TcSpecPrags
-- Pre-condition: the poly_id is zonked
-- Reason: required by tcSubExp
-tcPrags _rec_group _multi_bind is_overloaded_id poly_id prag_sigs
- = do { poly_id' <- tc_inl inl_sigs
-
- ; spec_prags <- mapM (wrapLocM (tcSpecPrag poly_id')) spec_sigs
-
- ; unless (null spec_sigs || is_overloaded_id) warn_discarded_spec
-
- ; unless (null bad_sigs) warn_discarded_sigs
-
- ; return (poly_id', spec_prags) }
+tcSpecPrags poly_id prag_sigs
+ = do { unless (null bad_sigs) warn_discarded_sigs
+ ; mapAndRecoverM (wrapLocM (tcSpec poly_id)) spec_sigs }
where
- (inl_sigs, other_sigs) = partition isInlineLSig prag_sigs
- (spec_sigs, bad_sigs) = partition isSpecLSig other_sigs
+ spec_sigs = filter isSpecLSig prag_sigs
+ bad_sigs = filter is_bad_sig prag_sigs
+ is_bad_sig s = not (isSpecLSig s || isInlineLSig s)
- warn_discarded_spec = warnPrags poly_id spec_sigs $
- ptext (sLit "SPECIALISE pragmas for non-overloaded function")
- warn_dup_inline = warnPrags poly_id inl_sigs $
- ptext (sLit "Duplicate INLINE pragmas for")
warn_discarded_sigs = warnPrags poly_id bad_sigs $
ptext (sLit "Discarding unexpected pragmas for")
- -----------
- tc_inl [] = return poly_id
- tc_inl (L loc (InlineSig _ prag) : other_inls)
- = do { unless (null other_inls) (setSrcSpan loc warn_dup_inline)
- ; return (poly_id `setInlinePragma` prag) }
- tc_inl _ = panic "tc_inl"
-
-{- Earlier we tried to warn about
- (a) INLINE for recursive function
- (b) INLINE for function that is part of a multi-binder group
- Code fragments below. But we want to allow
- {-# INLINE f #-}
- f x = x : g y
- g y = ....f...f....
- even though they are mutually recursive.
- So I'm just omitting the warnings for now
-
- | multi_bind && isInlinePragma prag
- = do { setSrcSpan loc $ addWarnTc multi_bind_warn
- ; return poly_id }
- | otherwise
- ; when (isInlinePragma prag && isRec rec_group)
- (setSrcSpan loc (addWarnTc rec_inline_warn))
-
- rec_inline_warn = ptext (sLit "INLINE pragma for recursive binder")
- <+> quotes (ppr poly_id) <+> ptext (sLit "may be discarded")
-
- multi_bind_warn = hang (ptext (sLit "Discarding INLINE pragma for") <+> quotes (ppr poly_id))
- 2 (ptext (sLit "because it is bound by a pattern, or mutual recursion") )
--}
-
-
-warnPrags :: Id -> [LSig Name] -> SDoc -> TcM ()
-warnPrags id bad_sigs herald
- = addWarnTc (hang (herald <+> quotes (ppr id))
- 2 (ppr_sigs bad_sigs))
- where
- ppr_sigs sigs = vcat (map (ppr . getLoc) sigs)
--------------
-tcSpecPrag :: TcId -> Sig Name -> TcM TcSpecPrag
-tcSpecPrag poly_id prag@(SpecSig _ hs_ty inl)
+tcSpec :: TcId -> Sig Name -> TcM TcSpecPrag
+tcSpec poly_id prag@(SpecSig _ hs_ty inl)
+ -- The Name in the SpecSig may not be the same as that of the poly_id
+ -- Example: SPECIALISE for a class method: the Name in the SpecSig is
+ -- for the selector Id, but the poly_id is something like $cop
= addErrCtxt (spec_ctxt prag) $
- do { let name = idName poly_id
- sig_ctxt = FunSigCtxt name
- ; spec_ty <- tcHsSigType sig_ctxt hs_ty
- ; wrap <- tcSubType (SpecPragOrigin name) (SigSkol sig_ctxt)
- (idType poly_id) spec_ty
- ; return (SpecPrag wrap inl) }
+ do { spec_ty <- tcHsSigType sig_ctxt hs_ty
+ ; checkTc (isOverloadedTy poly_ty)
+ (ptext (sLit "Discarding pragma for non-overloaded function") <+> quotes (ppr poly_id))
+ ; wrap <- tcSubType origin skol_info (idType poly_id) spec_ty
+ ; return (SpecPrag poly_id wrap inl) }
where
+ name = idName poly_id
+ poly_ty = idType poly_id
+ origin = SpecPragOrigin name
+ sig_ctxt = FunSigCtxt name
+ skol_info = SigSkol sig_ctxt
spec_ctxt prag = hang (ptext (sLit "In the SPECIALISE pragma")) 2 (ppr prag)
-tcSpecPrag _ sig = pprPanic "tcSpecPrag" (ppr sig)
+
+tcSpec _ prag = pprPanic "tcSpec" (ppr prag)
+
+--------------
+tcImpPrags :: [LSig Name] -> TcM [LTcSpecPrag]
+tcImpPrags prags
+ = do { this_mod <- getModule
+ ; let is_imp prag
+ = case sigName prag of
+ Nothing -> False
+ Just name -> not (nameIsLocalOrFrom this_mod name)
+ (spec_prags, others) = partition isSpecLSig $
+ filter is_imp prags
+ ; mapM_ misplacedSigErr others
+ -- Messy that this misplaced-sig error comes here
+ -- but the others come from the renamer
+ ; mapAndRecoverM (wrapLocM tcImpSpec) spec_prags }
+
+tcImpSpec :: Sig Name -> TcM TcSpecPrag
+tcImpSpec prag@(SpecSig (L _ name) _ _)
+ = do { id <- tcLookupId name
+ ; checkTc (isInlinePragma (idInlinePragma id))
+ (impSpecErr name)
+ ; tcSpec id prag }
+tcImpSpec p = pprPanic "tcImpSpec" (ppr p)
+
+impSpecErr :: Name -> SDoc
+impSpecErr name
+ = hang (ptext (sLit "You cannot SPECIALISE") <+> quotes (ppr name))
+ 2 (ptext (sLit "because its definition has no INLINE/INLINABLE pragma"))
--------------
-- If typechecking the binds fails, then return with each
The signatures have been dealt with already.
\begin{code}
-tcMonoBinds :: TcSigFun
- -> Bool -- True <=> no generalisation will be done for this binding
+tcMonoBinds :: TcSigFun -> LetBndrSpec
-> RecFlag -- Whether the binding is recursive for typechecking purposes
-- i.e. the binders are mentioned in their RHSs, and
-- we are not resuced by a type signature
setSrcSpan b_loc $
do { ((co_fn, matches'), rhs_ty) <- tcInfer (tcMatchesFun name inf matches)
- ; mono_id <- newLetBndr no_gen name rhs_ty
+ ; mono_id <- newNoSigLetBndr no_gen name rhs_ty
; return (unitBag (L b_loc (FunBind { fun_id = L nm_loc mono_id, fun_infix = inf,
fun_matches = matches', bind_fvs = fvs,
fun_co_fn = co_fn, fun_tick = Nothing })),
-- it; hence the TcMonoBind data type in which the LHS is done but the RHS isn't
data TcMonoBind -- Half completed; LHS done, RHS not done
- = TcFunBind MonoBindInfo (Located TcId) Bool (MatchGroup Name)
+ = TcFunBind MonoBindInfo SrcSpan Bool (MatchGroup Name)
| TcPatBind [MonoBindInfo] (LPat TcId) (GRHSs Name) TcSigmaType
type MonoBindInfo = (Name, Maybe TcSigInfo, TcId)
getMonoType :: MonoBindInfo -> TcTauType
getMonoType (_,_,mono_id) = idType mono_id
-tcLhs :: TcSigFun -> Bool -> HsBind Name -> TcM TcMonoBind
+tcLhs :: TcSigFun -> LetBndrSpec -> HsBind Name -> TcM TcMonoBind
tcLhs sig_fn no_gen (FunBind { fun_id = L nm_loc name, fun_infix = inf, fun_matches = matches })
- = do { mono_id <- newLhsBndr mb_sig no_gen name
- ; return (TcFunBind (name, mb_sig, mono_id) (L nm_loc mono_id) inf matches) }
- where
- mb_sig = sig_fn name
+ | Just sig <- sig_fn name
+ = do { mono_id <- newSigLetBndr no_gen name sig
+ ; return (TcFunBind (name, Just sig, mono_id) nm_loc inf matches) }
+ | otherwise
+ = do { mono_ty <- newFlexiTyVarTy argTypeKind
+ ; mono_id <- newNoSigLetBndr no_gen name mono_ty
+ ; return (TcFunBind (name, Nothing, mono_id) nm_loc inf matches) }
tcLhs sig_fn no_gen (PatBind { pat_lhs = pat, pat_rhs = grhss })
= do { let tc_pat exp_ty = tcLetPat sig_fn no_gen pat exp_ty $
tcLhs _ _ other_bind = pprPanic "tcLhs" (ppr other_bind)
-- AbsBind, VarBind impossible
------------------
-newLhsBndr :: Maybe TcSigInfo -> Bool -> Name -> TcM TcId
--- cf TcPat.tcPatBndr (LetPat case)
-newLhsBndr (Just sig) no_gen name
- | no_gen = return (sig_id sig)
- | otherwise = do { mono_name <- newLocalName name
- ; return (mkLocalId mono_name (sig_tau sig)) }
-
-newLhsBndr Nothing no_gen name
- = do { mono_ty <- newFlexiTyVarTy argTypeKind
- ; newLetBndr no_gen name mono_ty }
-
-------------------
tcRhs :: TcMonoBind -> TcM (HsBind TcId)
-- When we are doing pattern bindings, or multiple function bindings at a time
-- we *don't* bring any scoped type variables into scope
-- Wny not? They are not completely rigid.
-- That's why we have the special case for a single FunBind in tcMonoBinds
-tcRhs (TcFunBind (_,_,mono_id) fun' inf matches)
+tcRhs (TcFunBind (_,_,mono_id) loc inf matches)
= do { (co_fn, matches') <- tcMatchesFun (idName mono_id) inf
matches (idType mono_id)
- ; return (FunBind { fun_id = fun', fun_infix = inf, fun_matches = matches'
+ ; return (FunBind { fun_id = L loc mono_id, fun_infix = inf
+ , fun_matches = matches'
, fun_co_fn = co_fn
, bind_fvs = placeHolderNames, fun_tick = Nothing }) }
in
fm
-
-
%************************************************************************
%* *
Signatures
| Just sig <- one_funbind_with_sig binds = if null (sig_tvs sig) && null (sig_theta sig)
then NoGen -- Optimise common case
else CheckGen sig
- | (dopt Opt_MonoLocalBinds dflags
+ | (xopt Opt_MonoLocalBinds dflags
&& isNotTopLevel top_lvl) = NoGen
| otherwise = InferGen mono_restriction
--- | all no_sig bndrs = InferGen mono_restriction
--- | otherwise = NoGen -- A mixture of function
--- -- and pattern bindings
where
- mono_pat_binds = dopt Opt_MonoPatBinds dflags
+ mono_pat_binds = xopt Opt_MonoPatBinds dflags
&& any (is_pat_bind . unLoc) binds
- mono_restriction = dopt Opt_MonomorphismRestriction dflags
+ mono_restriction = xopt Opt_MonomorphismRestriction dflags
&& any (restricted . unLoc) binds
no_sig n = isNothing (sig_fn n)
where
id1 = sig_id sig1
id2 = sig_id sig2
-
------------------------------------------------
-{-
-badStrictSig :: Bool -> TcSigInfo -> SDoc
-badStrictSig unlifted sig
- = hang (ptext (sLit "Illegal polymorphic signature in") <+> msg)
- 2 (ppr sig)
- where
- msg | unlifted = ptext (sLit "an unlifted binding")
- | otherwise = ptext (sLit "a bang-pattern binding")
-
-restrictedBindSigErr :: [Name] -> SDoc
-restrictedBindSigErr binder_names
- = hang (ptext (sLit "Illegal type signature(s)"))
- 2 (vcat [ptext (sLit "in a binding group for") <+> pprBinders binder_names,
- ptext (sLit "that falls under the monomorphism restriction")])
-
-genCtxt :: [Name] -> SDoc
-genCtxt binder_names
- = ptext (sLit "When generalising the type(s) for") <+> pprBinders binder_names
--}
-
-missingSigWarn :: TcId -> TcM ()
-missingSigWarn id
- = do { env0 <- tcInitTidyEnv
- ; let (env1, tidy_ty) = tidyOpenType env0 (idType id)
- ; addWarnTcM (env1, mk_msg tidy_ty) }
- where
- name = idName id
- mk_msg ty = vcat [ptext (sLit "Definition but no type signature for") <+> quotes (ppr name),
- sep [ptext (sLit "Inferred type:") <+> pprHsVar name <+> dcolon <+> ppr ty]]
\end{code}
projects / ghc-hetmet.git / blobdiff