2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcIfaceSig]{Type checking of type signatures in interface files}
7 module TcIfaceSig ( tcInterfaceSigs, tcVar, tcCoreExpr, tcCoreLamBndrs ) where
9 #include "HsVersions.h"
11 import HsSyn ( TyClDecl(..), HsTupCon(..) )
13 import TcMonoType ( tcIfaceType )
14 import TcEnv ( RecTcEnv, tcExtendTyVarEnv,
15 tcExtendGlobalValEnv, tcSetEnv, tcEnvIds,
16 tcLookupGlobal_maybe, tcLookupRecId_maybe
19 import RnHsSyn ( RenamedTyClDecl )
21 import Literal ( Literal(..) )
23 import CoreUtils ( exprType )
25 import CoreLint ( lintUnfolding )
26 import WorkWrap ( mkWrapper )
28 import Id ( Id, mkVanillaGlobal, mkLocalId, idName, isDataConWrapId_maybe )
29 import Module ( Module )
30 import MkId ( mkFCallId )
32 import TyCon ( tyConDataCons )
33 import DataCon ( DataCon, dataConId, dataConSig, dataConArgTys )
34 import Type ( mkTyVarTys, splitTyConApp )
35 import TysWiredIn ( tupleCon )
36 import Var ( mkTyVar, tyVarKind )
37 import Name ( Name, nameIsLocalOrFrom )
38 import ErrUtils ( pprBagOfErrors )
40 import Util ( zipWithEqual )
41 import HscTypes ( TyThing(..) )
44 Ultimately, type signatures in interfaces will have pragmatic
45 information attached, so it is a good idea to have separate code to
48 As always, we do not have to worry about user-pragmas in interface
52 tcInterfaceSigs :: RecTcEnv -- Envt to use when checking unfoldings
53 -> Module -- This module
54 -> [RenamedTyClDecl] -- Ignore non-sig-decls in these decls
58 tcInterfaceSigs unf_env mod decls
59 = listTc [ do_one name ty id_infos src_loc
60 | IfaceSig {tcdName = name, tcdType = ty, tcdIdInfo = id_infos, tcdLoc =src_loc} <- decls]
62 in_scope_vars = filter (nameIsLocalOrFrom mod . idName) (tcEnvIds unf_env)
63 -- Oops: using isLocalId instead can give a black hole
64 -- because it looks at the idinfo
66 -- When we have hi-boot files, an unfolding might refer to
67 -- something defined in this module, so we must build a
68 -- suitable in-scope set. This thunk will only be poked
69 -- if -dcore-lint is on.
71 do_one name ty id_infos src_loc
72 = tcAddSrcLoc src_loc $
73 tcAddErrCtxt (ifaceSigCtxt name) $
74 tcIfaceType ty `thenTc` \ sigma_ty ->
75 tcIdInfo unf_env in_scope_vars name
76 sigma_ty id_infos `thenTc` \ id_info ->
77 returnTc (mkVanillaGlobal name sigma_ty id_info)
81 tcIdInfo unf_env in_scope_vars name ty info_ins
82 = foldlTc tcPrag init_info info_ins
84 -- set the CgInfo to something sensible but uninformative before
85 -- we start, because the default CgInfo is a panic.
86 init_info = vanillaIdInfo `setCgInfo` vanillaCgInfo
88 tcPrag info (HsNoCafRefs) = returnTc (info `setCafInfo` NoCafRefs)
90 tcPrag info (HsArity arity) =
91 returnTc (info `setArityInfo` arity
94 tcPrag info (HsUnfold inline_prag expr)
95 = tcPragExpr unf_env name in_scope_vars expr `thenNF_Tc` \ maybe_expr' ->
97 -- maybe_expr doesn't get looked at if the unfolding
98 -- is never inspected; so the typecheck doesn't even happen
99 unfold_info = case maybe_expr' of
100 Nothing -> noUnfolding
101 Just expr' -> mkTopUnfolding expr'
102 info1 = info `setUnfoldingInfo` unfold_info
103 info2 = info1 `setInlinePragInfo` inline_prag
107 tcPrag info (HsStrictness strict_info)
108 = returnTc (info `setNewStrictnessInfo` Just strict_info)
110 tcPrag info (HsWorker nm arity)
111 = tcWorkerInfo unf_env ty info nm arity
115 tcWorkerInfo unf_env ty info worker_name arity
116 = uniqSMToTcM (mkWrapper ty strict_sig) `thenNF_Tc` \ wrap_fn ->
118 -- Watch out! We can't pull on unf_env too eagerly!
119 info' = case tcLookupRecId_maybe unf_env worker_name of
121 info `setUnfoldingInfo` mkTopUnfolding (wrap_fn worker_id)
122 `setWorkerInfo` HasWorker worker_id arity
124 Nothing -> pprTrace "tcWorkerInfo failed:"
125 (ppr worker_name) info
129 -- We are relying here on strictness info always appearing
130 -- before worker info, fingers crossed ....
131 strict_sig = case newStrictnessInfo info of
133 Nothing -> pprPanic "Worker info but no strictness for" (ppr worker_name)
136 For unfoldings we try to do the job lazily, so that we never type check
137 an unfolding that isn't going to be looked at.
140 tcPragExpr unf_env name in_scope_vars expr
141 = tcDelay unf_env doc $
142 tcCoreExpr expr `thenTc` \ core_expr' ->
144 -- Check for type consistency in the unfolding
145 tcGetSrcLoc `thenNF_Tc` \ src_loc ->
146 getDOptsTc `thenTc` \ dflags ->
147 case lintUnfolding dflags src_loc in_scope_vars core_expr' of
148 (Nothing,_) -> returnTc core_expr' -- ignore warnings
149 (Just fail_msg,_) -> failWithTc ((doc <+> text "failed Lint") $$ fail_msg)
151 doc = text "unfolding of" <+> ppr name
153 tcDelay :: RecTcEnv -> SDoc -> TcM a -> NF_TcM (Maybe a)
154 tcDelay unf_env doc thing_inside
156 recoverNF_Tc bad_value (
157 tcSetEnv unf_env thing_inside `thenTc` \ r ->
161 -- The trace tells what wasn't available, for the benefit of
162 -- compiler hackers who want to improve it!
163 bad_value = getErrsTc `thenNF_Tc` \ (warns,errs) ->
164 returnNF_Tc (pprTrace "Failed:"
165 (hang doc 4 (pprBagOfErrors errs))
170 Variables in unfoldings
171 ~~~~~~~~~~~~~~~~~~~~~~~
172 ****** Inside here we use only the Global environment, even for locally bound variables.
173 ****** Why? Because we know all the types and want to bind them to real Ids.
176 tcVar :: Name -> TcM Id
178 = tcLookupGlobal_maybe name `thenNF_Tc` \ maybe_id ->
180 Just (AnId id) -> returnTc id ;
181 Nothing -> failWithTc (noDecl name)
184 noDecl name = hsep [ptext SLIT("Warning: no binding for"), ppr name]
190 tcCoreExpr :: UfExpr Name -> TcM CoreExpr
192 tcCoreExpr (UfType ty)
193 = tcIfaceType ty `thenTc` \ ty' ->
194 -- It might not be of kind type
197 tcCoreExpr (UfVar name)
198 = tcVar name `thenTc` \ id ->
201 tcCoreExpr (UfLit lit)
204 -- The dreaded lit-lits are also similar, except here the type
205 -- is read in explicitly rather than being implicit
206 tcCoreExpr (UfLitLit lit ty)
207 = tcIfaceType ty `thenTc` \ ty' ->
208 returnTc (Lit (MachLitLit lit ty'))
210 tcCoreExpr (UfFCall cc ty)
211 = tcIfaceType ty `thenTc` \ ty' ->
212 tcGetUnique `thenNF_Tc` \ u ->
213 returnTc (Var (mkFCallId u cc ty'))
215 tcCoreExpr (UfTuple (HsTupCon _ boxity arity) args)
216 = mapTc tcCoreExpr args `thenTc` \ args' ->
218 -- Put the missing type arguments back in
219 con_args = map (Type . exprType) args' ++ args'
221 returnTc (mkApps (Var con_id) con_args)
223 con_id = dataConId (tupleCon boxity arity)
226 tcCoreExpr (UfLam bndr body)
227 = tcCoreLamBndr bndr $ \ bndr' ->
228 tcCoreExpr body `thenTc` \ body' ->
229 returnTc (Lam bndr' body')
231 tcCoreExpr (UfApp fun arg)
232 = tcCoreExpr fun `thenTc` \ fun' ->
233 tcCoreExpr arg `thenTc` \ arg' ->
234 returnTc (App fun' arg')
236 tcCoreExpr (UfCase scrut case_bndr alts)
237 = tcCoreExpr scrut `thenTc` \ scrut' ->
239 scrut_ty = exprType scrut'
240 case_bndr' = mkLocalId case_bndr scrut_ty
242 tcExtendGlobalValEnv [case_bndr'] $
243 mapTc (tcCoreAlt scrut_ty) alts `thenTc` \ alts' ->
244 returnTc (Case scrut' case_bndr' alts')
246 tcCoreExpr (UfLet (UfNonRec bndr rhs) body)
247 = tcCoreExpr rhs `thenTc` \ rhs' ->
248 tcCoreValBndr bndr $ \ bndr' ->
249 tcCoreExpr body `thenTc` \ body' ->
250 returnTc (Let (NonRec bndr' rhs') body')
252 tcCoreExpr (UfLet (UfRec pairs) body)
253 = tcCoreValBndrs bndrs $ \ bndrs' ->
254 mapTc tcCoreExpr rhss `thenTc` \ rhss' ->
255 tcCoreExpr body `thenTc` \ body' ->
256 returnTc (Let (Rec (bndrs' `zip` rhss')) body')
258 (bndrs, rhss) = unzip pairs
260 tcCoreExpr (UfNote note expr)
261 = tcCoreExpr expr `thenTc` \ expr' ->
263 UfCoerce to_ty -> tcIfaceType to_ty `thenTc` \ to_ty' ->
264 returnTc (Note (Coerce to_ty'
265 (exprType expr')) expr')
266 UfInlineCall -> returnTc (Note InlineCall expr')
267 UfInlineMe -> returnTc (Note InlineMe expr')
268 UfSCC cc -> returnTc (Note (SCC cc) expr')
272 tcCoreLamBndr (UfValBinder name ty) thing_inside
273 = tcIfaceType ty `thenTc` \ ty' ->
275 id = mkLocalId name ty'
277 tcExtendGlobalValEnv [id] $
280 tcCoreLamBndr (UfTyBinder name kind) thing_inside
282 tyvar = mkTyVar name kind
284 tcExtendTyVarEnv [tyvar] (thing_inside tyvar)
286 tcCoreLamBndrs [] thing_inside = thing_inside []
287 tcCoreLamBndrs (b:bs) thing_inside
288 = tcCoreLamBndr b $ \ b' ->
289 tcCoreLamBndrs bs $ \ bs' ->
290 thing_inside (b':bs')
292 tcCoreValBndr (UfValBinder name ty) thing_inside
293 = tcIfaceType ty `thenTc` \ ty' ->
295 id = mkLocalId name ty'
297 tcExtendGlobalValEnv [id] $
300 tcCoreValBndrs bndrs thing_inside -- Expect them all to be ValBinders
301 = mapTc tcIfaceType tys `thenTc` \ tys' ->
303 ids = zipWithEqual "tcCoreValBndr" mkLocalId names tys'
305 tcExtendGlobalValEnv ids $
308 names = [name | UfValBinder name _ <- bndrs]
309 tys = [ty | UfValBinder _ ty <- bndrs]
313 tcCoreAlt scrut_ty (UfDefault, names, rhs)
314 = ASSERT( null names )
315 tcCoreExpr rhs `thenTc` \ rhs' ->
316 returnTc (DEFAULT, [], rhs')
318 tcCoreAlt scrut_ty (UfLitAlt lit, names, rhs)
319 = ASSERT( null names )
320 tcCoreExpr rhs `thenTc` \ rhs' ->
321 returnTc (LitAlt lit, [], rhs')
323 tcCoreAlt scrut_ty (UfLitLitAlt str ty, names, rhs)
324 = ASSERT( null names )
325 tcCoreExpr rhs `thenTc` \ rhs' ->
326 tcIfaceType ty `thenTc` \ ty' ->
327 returnTc (LitAlt (MachLitLit str ty'), [], rhs')
329 -- A case alternative is made quite a bit more complicated
330 -- by the fact that we omit type annotations because we can
331 -- work them out. True enough, but its not that easy!
332 tcCoreAlt scrut_ty alt@(con, names, rhs)
333 = tcConAlt con `thenTc` \ con ->
335 (main_tyvars, _, ex_tyvars, _, _, _) = dataConSig con
337 (tycon, inst_tys) = splitTyConApp scrut_ty -- NB: not tcSplitTyConApp
338 -- We are looking at Core here
339 ex_tyvars' = [mkTyVar name (tyVarKind tv) | (name,tv) <- names `zip` ex_tyvars]
340 ex_tys' = mkTyVarTys ex_tyvars'
341 arg_tys = dataConArgTys con (inst_tys ++ ex_tys')
342 id_names = drop (length ex_tyvars) names
345 | length id_names /= length arg_tys
346 = pprPanic "tcCoreAlts" (ppr (con, names, rhs) $$
347 (ppr main_tyvars <+> ppr ex_tyvars) $$
351 = zipWithEqual "tcCoreAlts" mkLocalId id_names arg_tys
353 ASSERT( con `elem` tyConDataCons tycon && length inst_tys == length main_tyvars )
354 tcExtendTyVarEnv ex_tyvars' $
355 tcExtendGlobalValEnv arg_ids $
356 tcCoreExpr rhs `thenTc` \ rhs' ->
357 returnTc (DataAlt con, ex_tyvars' ++ arg_ids, rhs')
360 tcConAlt :: UfConAlt Name -> TcM DataCon
361 tcConAlt (UfTupleAlt (HsTupCon _ boxity arity))
362 = returnTc (tupleCon boxity arity)
364 tcConAlt (UfDataAlt con_name)
365 = tcVar con_name `thenTc` \ con_id ->
366 returnTc (case isDataConWrapId_maybe con_id of
368 Nothing -> pprPanic "tcCoreAlt" (ppr con_id))
372 ifaceSigCtxt sig_name
373 = hsep [ptext SLIT("In an interface-file signature for"), ppr sig_name]