%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcBinds]{TcBinds}
import {-# SOURCE #-} TcMatches ( tcGRHSsPat, tcMatchesFun )
import {-# SOURCE #-} TcExpr ( tcMonoExpr )
-import DynFlags ( dopt, DynFlags,
- DynFlag(Opt_MonomorphismRestriction, Opt_MonoPatBinds, Opt_GlasgowExts) )
-import HsSyn ( HsExpr(..), HsBind(..), LHsBinds, LHsBind, Sig(..),
- HsLocalBinds(..), HsValBinds(..), HsIPBinds(..),
- LSig, Match(..), IPBind(..), Prag(..),
- HsType(..), LHsType, HsExplicitForAll(..), hsLTyVarNames,
- isVanillaLSig, sigName, placeHolderNames, isPragLSig,
- LPat, GRHSs, MatchGroup(..), pprLHsBinds, mkHsCoerce,
- collectHsBindBinders, collectPatBinders, pprPatBind, isBangHsBind
- )
-import TcHsSyn ( zonkId )
+import DynFlags
+import HsSyn
+import TcHsSyn
import TcRnMonad
-import Inst ( newDictBndrs, newIPDict, instToId )
-import TcEnv ( tcExtendIdEnv, tcExtendIdEnv2, tcExtendTyVarEnv2,
- pprBinders, tcLookupId,
- tcGetGlobalTyVars )
-import TcUnify ( tcInfer, tcSubExp, unifyTheta,
- bleatEscapedTvs, sigCtxt )
-import TcSimplify ( tcSimplifyInfer, tcSimplifyInferCheck,
- tcSimplifyRestricted, tcSimplifyIPs )
-import TcHsType ( tcHsSigType, UserTypeCtxt(..) )
-import TcPat ( tcLetPat )
-import TcSimplify ( bindInstsOfLocalFuns )
-import TcMType ( newFlexiTyVarTy, zonkQuantifiedTyVar, zonkSigTyVar,
- tcInstSigTyVars, tcInstSkolTyVars, tcInstType,
- zonkTcType, zonkTcTypes, zonkTcTyVar )
-import TcType ( TcType, TcTyVar, TcThetaType,
- SkolemInfo(SigSkol), UserTypeCtxt(FunSigCtxt),
- TcTauType, TcSigmaType, isUnboxedTupleType,
- mkTyVarTy, mkForAllTys, mkFunTys, exactTyVarsOfType,
- mkForAllTy, isUnLiftedType, tcGetTyVar,
- mkTyVarTys, tidyOpenTyVar )
-import {- Kind parts of -} Type ( argTypeKind )
-import VarEnv ( TyVarEnv, emptyVarEnv, lookupVarEnv, extendVarEnv )
-import TysPrim ( alphaTyVar )
-import Id ( Id, mkLocalId, mkVanillaGlobal )
-import IdInfo ( vanillaIdInfo )
-import Var ( TyVar, idType, idName )
-import Name ( Name )
+import Inst
+import TcEnv
+import TcUnify
+import TcSimplify
+import TcHsType
+import TcPat
+import TcMType
+import TcType
+import {- Kind parts of -} Type
+import VarEnv
+import TysPrim
+import Id
+import IdInfo
+import Var ( TyVar )
+import Name
import NameSet
import NameEnv
import VarSet
-import SrcLoc ( Located(..), unLoc, getLoc )
+import SrcLoc
import Bag
-import ErrUtils ( Message )
-import Digraph ( SCC(..), stronglyConnComp )
-import Maybes ( expectJust, isJust, isNothing, orElse )
-import Util ( singleton )
-import BasicTypes ( TopLevelFlag(..), isTopLevel, isNotTopLevel,
- RecFlag(..), isNonRec, InlineSpec, defaultInlineSpec )
+import ErrUtils
+import Digraph
+import Maybes
+import List
+import Util
+import BasicTypes
import Outputable
\end{code}
-- Extend the envt right away with all
-- the Ids declared with type signatures
- ; gla_exts <- doptM Opt_GlasgowExts
+ ; poly_rec <- doptM Opt_RelaxedPolyRec
; (binds', thing) <- tcExtendIdEnv poly_ids $
- tc_val_binds gla_exts top_lvl sig_fn prag_fn
+ tc_val_binds poly_rec top_lvl sig_fn prag_fn
binds thing_inside
; return (ValBindsOut binds' sigs, thing) }
-- Typecheck a whole lot of value bindings,
-- one strongly-connected component at a time
-tc_val_binds gla_exts top_lvl sig_fn prag_fn [] thing_inside
+tc_val_binds poly_rec top_lvl sig_fn prag_fn [] thing_inside
= do { thing <- thing_inside
; return ([], thing) }
-tc_val_binds gla_exts top_lvl sig_fn prag_fn (group : groups) thing_inside
+tc_val_binds poly_rec top_lvl sig_fn prag_fn (group : groups) thing_inside
= do { (group', (groups', thing))
- <- tc_group gla_exts top_lvl sig_fn prag_fn group $
- tc_val_binds gla_exts top_lvl sig_fn prag_fn groups thing_inside
+ <- tc_group poly_rec top_lvl sig_fn prag_fn group $
+ tc_val_binds poly_rec top_lvl sig_fn prag_fn groups thing_inside
; return (group' ++ groups', thing) }
------------------------
-- We get a list of groups back, because there may
-- be specialisations etc as well
-tc_group gla_exts top_lvl sig_fn prag_fn (NonRecursive, binds) thing_inside
+tc_group poly_rec top_lvl sig_fn prag_fn (NonRecursive, binds) thing_inside
-- A single non-recursive binding
-- We want to keep non-recursive things non-recursive
-- so that we desugar unlifted bindings correctly
= do { (binds, thing) <- tc_haskell98 top_lvl sig_fn prag_fn NonRecursive binds thing_inside
; return ([(NonRecursive, b) | b <- binds], thing) }
-tc_group gla_exts top_lvl sig_fn prag_fn (Recursive, binds) thing_inside
- | not gla_exts -- Recursive group, normal Haskell 98 route
+tc_group poly_rec top_lvl sig_fn prag_fn (Recursive, binds) thing_inside
+ | not poly_rec -- Recursive group, normal Haskell 98 route
= do { (binds1, thing) <- tc_haskell98 top_lvl sig_fn prag_fn Recursive binds thing_inside
; return ([(Recursive, unionManyBags binds1)], thing) }
-- TYPECHECK THE BINDINGS
; ((binds', mono_bind_infos), lie_req)
<- getLIE (tcMonoBinds bind_list sig_fn rec_tc)
+ ; traceTc (text "temp" <+> (ppr binds' $$ ppr lie_req))
-- CHECK FOR UNLIFTED BINDINGS
-- These must be non-recursive etc, and are not generalised
else do -- The normal lifted case: GENERALISE
{ dflags <- getDOpts
- ; (tyvars_to_gen, dict_binds, dict_ids)
+ ; (tyvars_to_gen, dicts, dict_binds)
<- addErrCtxt (genCtxt (bndrNames mono_bind_infos)) $
generalise dflags top_lvl bind_list sig_fn mono_bind_infos lie_req
- -- FINALISE THE QUANTIFIED TYPE VARIABLES
- -- The quantified type variables often include meta type variables
- -- we want to freeze them into ordinary type variables, and
- -- default their kind (e.g. from OpenTypeKind to TypeKind)
- ; tyvars_to_gen' <- mappM zonkQuantifiedTyVar tyvars_to_gen
-
-- BUILD THE POLYMORPHIC RESULT IDs
- ; exports <- mapM (mkExport prag_fn tyvars_to_gen' (map idType dict_ids))
+ ; let dict_ids = map instToId dicts
+ ; exports <- mapM (mkExport top_lvl prag_fn tyvars_to_gen (map idType dict_ids))
mono_bind_infos
; let poly_ids = [poly_id | (_, poly_id, _, _) <- exports]
; traceTc (text "binding:" <+> ppr (poly_ids `zip` map idType poly_ids))
- ; let abs_bind = L loc $ AbsBinds tyvars_to_gen'
+ ; let abs_bind = L loc $ AbsBinds tyvars_to_gen
dict_ids exports
(dict_binds `unionBags` binds')
--------------
-mkExport :: TcPragFun -> [TyVar] -> [TcType] -> MonoBindInfo
- -> TcM ([TyVar], Id, Id, [Prag])
+mkExport :: TopLevelFlag -> TcPragFun -> [TyVar] -> [TcType]
+ -> MonoBindInfo
+ -> TcM ([TyVar], Id, Id, [LPrag])
-- mkExport generates exports with
-- zonked type variables,
-- zonked poly_ids
-- Pre-condition: the inferred_tvs are already zonked
-mkExport prag_fn inferred_tvs dict_tys (poly_name, mb_sig, mono_id)
- = do { (tvs, poly_id) <- mk_poly_id mb_sig
+mkExport top_lvl prag_fn inferred_tvs dict_tys (poly_name, mb_sig, mono_id)
+ = do { warn_missing_sigs <- doptM Opt_WarnMissingSigs
+ ; let warn = isTopLevel top_lvl && warn_missing_sigs
+ ; (tvs, poly_id) <- mk_poly_id warn mb_sig
; poly_id' <- zonkId poly_id
; prags <- tcPrags poly_id' (prag_fn poly_name)
where
poly_ty = mkForAllTys inferred_tvs (mkFunTys dict_tys (idType mono_id))
- mk_poly_id Nothing = return (inferred_tvs, mkLocalId poly_name poly_ty)
- mk_poly_id (Just sig) = do { tvs <- mapM zonk_tv (sig_tvs sig)
- ; return (tvs, sig_id sig) }
+ mk_poly_id warn Nothing = do { missingSigWarn warn poly_name poly_ty
+ ; return (inferred_tvs, mkLocalId poly_name poly_ty) }
+ mk_poly_id warn (Just sig) = do { tvs <- mapM zonk_tv (sig_tvs sig)
+ ; return (tvs, sig_id sig) }
zonk_tv tv = do { ty <- zonkTcTyVar tv; return (tcGetTyVar "mkExport" ty) }
env = foldl add emptyNameEnv prs
add env (n,p) = extendNameEnv_Acc (:) singleton env n p
-tcPrags :: Id -> [LSig Name] -> TcM [Prag]
-tcPrags poly_id prags = mapM tc_prag prags
+tcPrags :: Id -> [LSig Name] -> TcM [LPrag]
+tcPrags poly_id prags = mapM (wrapLocM tc_prag) prags
where
- tc_prag (L loc prag) = setSrcSpan loc $
- addErrCtxt (pragSigCtxt prag) $
- tcPrag poly_id prag
+ tc_prag prag = addErrCtxt (pragSigCtxt prag) $
+ tcPrag poly_id prag
pragSigCtxt prag = hang (ptext SLIT("In the pragma")) 2 (ppr prag)
; (co_fn, lie) <- getLIE (tcSubExp (idType poly_id) spec_ty)
; extendLIEs lie
; let const_dicts = map instToId lie
- ; return (SpecPrag (mkHsCoerce co_fn (HsVar poly_id)) spec_ty const_dicts inl) }
+ ; return (SpecPrag (mkHsWrap co_fn (HsVar poly_id)) spec_ty const_dicts inl) }
-- Most of the work of specialisation is done by
-- the desugarer, guided by the SpecPrag
-- e.g. f = \(x::forall a. a->a) -> <body>
-- We want to infer a higher-rank type for f
setSrcSpan b_loc $
- do { ((co_fn, matches'), rhs_ty) <- tcInfer (tcMatchesFun name matches)
+ do { ((co_fn, matches'), rhs_ty) <- tcInfer (tcMatchesFun name inf matches)
-- Check for an unboxed tuple type
-- f = (# True, False #)
; let mono_id = mkLocalId mono_name zonked_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_co_fn = co_fn, fun_tick = Nothing })),
[(name, Nothing, mono_id)]) }
tcMonoBinds [L b_loc (FunBind { fun_id = L nm_loc name, fun_infix = inf,
| (name, tv) <- sig_scoped tc_sig `zip` sig_tvs tc_sig ]
; (co_fn, matches') <- tcExtendTyVarEnv2 rhs_tvs $
- tcMatchesFun mono_name matches mono_ty
+ tcMatchesFun mono_name inf matches mono_ty
; let fun_bind' = FunBind { fun_id = L nm_loc mono_id,
fun_infix = inf, fun_matches = matches',
- bind_fvs = placeHolderNames, fun_co_fn = co_fn }
+ bind_fvs = placeHolderNames, fun_co_fn = co_fn,
+ fun_tick = Nothing }
; return (unitBag (L b_loc fun_bind'),
[(name, Just tc_sig, mono_id)]) }
-------------------
tcRhs :: TcMonoBind -> TcM (HsBind TcId)
tcRhs (TcFunBind info fun'@(L _ mono_id) inf matches)
- = do { (co_fn, matches') <- tcMatchesFun (idName mono_id) matches
- (idType mono_id)
+ = do { (co_fn, matches') <- tcMatchesFun (idName mono_id) inf
+ matches (idType mono_id)
; return (FunBind { fun_id = fun', fun_infix = inf, fun_matches = matches',
- bind_fvs = placeHolderNames, fun_co_fn = co_fn }) }
+ bind_fvs = placeHolderNames, fun_co_fn = co_fn,
+ fun_tick = Nothing }) }
tcRhs bind@(TcPatBind _ pat' grhss pat_ty)
= do { grhss' <- addErrCtxt (patMonoBindsCtxt pat' grhss) $
generalise :: DynFlags -> TopLevelFlag
-> [LHsBind Name] -> TcSigFun
-> [MonoBindInfo] -> [Inst]
- -> TcM ([TcTyVar], TcDictBinds, [TcId])
+ -> TcM ([TyVar], [Inst], TcDictBinds)
+-- The returned [TyVar] are all ready to quantify
+
generalise dflags top_lvl bind_list sig_fn mono_infos lie_req
| isMonoGroup dflags bind_list
- = do { extendLIEs lie_req; return ([], emptyBag, []) }
+ = do { extendLIEs lie_req
+ ; return ([], [], emptyBag) }
| isRestrictedGroup dflags bind_list sig_fn -- RESTRICTED CASE
= -- Check signature contexts are empty
-- Check that signature type variables are OK
; final_qtvs <- checkSigsTyVars qtvs sigs
- ; return (final_qtvs, binds, []) }
+ ; return (final_qtvs, [], binds) }
| null sigs -- UNRESTRICTED CASE, NO TYPE SIGS
= tcSimplifyInfer doc tau_tvs lie_req
| otherwise -- UNRESTRICTED CASE, WITH TYPE SIGS
- = do { sig_lie <- unifyCtxts sigs -- sigs is non-empty
+ = do { sig_lie <- unifyCtxts sigs -- sigs is non-empty; sig_lie is zonked
; let -- The "sig_avails" is the stuff available. We get that from
-- the context of the type signature, BUT ALSO the lie_avail
-- so that polymorphic recursion works right (see Note [Polymorphic recursion])
local_meths = [mkMethInst sig mono_id | (_, Just sig, mono_id) <- mono_infos]
sig_avails = sig_lie ++ local_meths
+ loc = sig_loc (head sigs)
-- Check that the needed dicts can be
-- expressed in terms of the signature ones
- ; (forall_tvs, dict_binds) <- tcSimplifyInferCheck doc tau_tvs sig_avails lie_req
+ ; (qtvs, binds) <- tcSimplifyInferCheck loc tau_tvs sig_avails lie_req
-- Check that signature type variables are OK
- ; final_qtvs <- checkSigsTyVars forall_tvs sigs
+ ; final_qtvs <- checkSigsTyVars qtvs sigs
- ; returnM (final_qtvs, dict_binds, map instToId sig_lie) }
+ ; returnM (final_qtvs, sig_lie, binds) }
where
bndrs = bndrNames mono_infos
sigs = [sig | (_, Just sig, _) <- mono_infos]
mkMethInst (TcSigInfo { sig_id = poly_id, sig_tvs = tvs,
sig_theta = theta, sig_loc = loc }) mono_id
- = Method mono_id poly_id (mkTyVarTys tvs) theta loc
+ = Method {tci_id = mono_id, tci_oid = poly_id, tci_tys = mkTyVarTys tvs,
+ tci_theta = theta, tci_loc = loc}
\end{code}
unifyCtxts checks that all the signature contexts are the same
\begin{code}
unifyCtxts :: [TcSigInfo] -> TcM [Inst]
+-- Post-condition: the returned Insts are full zonked
unifyCtxts (sig1 : sigs) -- Argument is always non-empty
= do { mapM unify_ctxt sigs
- ; newDictBndrs (sig_loc sig1) (sig_theta sig1) }
+ ; theta <- zonkTcThetaType (sig_theta sig1)
+ ; newDictBndrs (sig_loc sig1) theta }
where
theta1 = sig_theta sig1
unify_ctxt :: TcSigInfo -> TcM ()
unify_ctxt sig@(TcSigInfo { sig_theta = theta })
- = setSrcSpan (instLocSrcSpan (sig_loc sig)) $
+ = setSrcSpan (instLocSpan (sig_loc sig)) $
addErrCtxt (sigContextsCtxt sig1 sig) $
unifyTheta theta1 theta
<+> quotes (ppr tidy_tv2)
; failWithTcM (env2, msg) }
where
-\end{code}
+\end{code}
@getTyVarsToGen@ decides what type variables to generalise over.
-- Precondition: no duplicates
mkTcSigFun sigs = lookupNameEnv env
where
- env = mkNameEnv [(name, scoped_tyvars hs_ty)
- | L span (TypeSig (L _ name) (L _ hs_ty)) <- sigs]
- scoped_tyvars (HsForAllTy Explicit tvs _ _) = hsLTyVarNames tvs
- scoped_tyvars other = []
+ env = mkNameEnv [(name, hsExplicitTvs lhs_ty)
+ | L span (TypeSig (L _ name) lhs_ty) <- sigs]
-- The scoped names are the ones explicitly mentioned
-- in the HsForAll. (There may be more in sigma_ty, because
-- of nested type synonyms. See Note [Scoped] with TcSigInfo.)
+ -- See Note [Only scoped tyvars are in the TyVarEnv]
---------------
data TcSigInfo
sig_loc :: InstLoc -- The location of the signature
}
+
+-- Note [Only scoped tyvars are in the TyVarEnv]
+-- We are careful to keep only the *lexically scoped* type variables in
+-- the type environment. Why? After all, the renamer has ensured
+-- that only legal occurrences occur, so we could put all type variables
+-- into the type env.
+--
+-- But we want to check that two distinct lexically scoped type variables
+-- do not map to the same internal type variable. So we need to know which
+-- the lexically-scoped ones are... and at the moment we do that by putting
+-- only the lexically scoped ones into the environment.
+
+
-- Note [Scoped]
-- There may be more instantiated type variables than scoped
-- ones. For example:
-- and remember the names from the original HsForAllTy in sig_scoped
-- Note [Instantiate sig]
--- It's vital to instantiate a type signature with fresh variable.
+-- It's vital to instantiate a type signature with fresh variables.
-- For example:
-- type S = forall a. a->a
-- f,g :: S
-- Instantiate the signature, with either skolems or meta-type variables
-- depending on the use_skols boolean. This variable is set True
-- when we are typechecking a single function binding; and False for
--- pattern bindigs and a group of several function bindings.
+-- pattern bindings and a group of several function bindings.
-- Reason: in the latter cases, the "skolems" can be unified together,
-- so they aren't properly rigid in the type-refinement sense.
-- NB: unless we are doing H98, each function with a sig will be done
= do { poly_id <- tcLookupId name -- Cannot fail; the poly ids are put into
-- scope when starting the binding group
; let skol_info = SigSkol (FunSigCtxt name)
- inst_tyvars | use_skols = tcInstSkolTyVars skol_info
- | otherwise = tcInstSigTyVars skol_info
+ inst_tyvars = tcInstSigTyVars use_skols skol_info
; (tvs, theta, tau) <- tcInstType inst_tyvars (idType poly_id)
; loc <- getInstLoc (SigOrigin skol_info)
; return (TcSigInfo { sig_id = poly_id,
genCtxt binder_names
= ptext SLIT("When generalising the type(s) for") <+> pprBinders binder_names
+
+missingSigWarn False name ty = return ()
+missingSigWarn True name ty
+ = do { env0 <- tcInitTidyEnv
+ ; let (env1, tidy_ty) = tidyOpenType env0 ty
+ ; addWarnTcM (env1, mk_msg tidy_ty) }
+ where
+ mk_msg ty = vcat [ptext SLIT("Definition but no type signature for") <+> quotes (ppr name),
+ sep [ptext SLIT("Inferred type:") <+> ppr name <+> dcolon <+> ppr ty]]
\end{code}
projects / ghc-hetmet.git / blobdiff