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, tcDelay, 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, dropList, equalLength )
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)
93 tcPrag info (HsUnfold inline_prag expr)
94 = tcPragExpr unf_env name in_scope_vars expr `thenNF_Tc` \ maybe_expr' ->
96 -- maybe_expr doesn't get looked at if the unfolding
97 -- is never inspected; so the typecheck doesn't even happen
98 unfold_info = case maybe_expr' of
99 Nothing -> noUnfolding
100 Just expr' -> mkTopUnfolding expr'
101 info1 = info `setUnfoldingInfo` unfold_info
102 info2 = info1 `setInlinePragInfo` inline_prag
106 tcPrag info (HsStrictness strict_info)
107 = returnTc (info `setAllStrictnessInfo` Just strict_info)
109 tcPrag info (HsWorker nm arity)
110 = tcWorkerInfo unf_env ty info nm arity
114 tcWorkerInfo unf_env ty info worker_name arity
115 = uniqSMToTcM (mkWrapper ty strict_sig) `thenNF_Tc` \ wrap_fn ->
117 -- Watch out! We can't pull on unf_env too eagerly!
118 info' = case tcLookupRecId_maybe unf_env worker_name of
120 info `setUnfoldingInfo` mkTopUnfolding (wrap_fn worker_id)
121 `setWorkerInfo` HasWorker worker_id arity
123 Nothing -> pprTrace "tcWorkerInfo failed:"
124 (ppr worker_name) info
128 -- We are relying here on strictness info always appearing
129 -- before worker info, fingers crossed ....
130 strict_sig = case newStrictnessInfo info of
132 Nothing -> pprPanic "Worker info but no strictness for" (ppr worker_name)
135 For unfoldings we try to do the job lazily, so that we never type check
136 an unfolding that isn't going to be looked at.
139 tcPragExpr unf_env name in_scope_vars expr
140 = tcDelay unf_env doc Nothing $
141 tcCoreExpr expr `thenTc` \ core_expr' ->
143 -- Check for type consistency in the unfolding
144 tcGetSrcLoc `thenNF_Tc` \ src_loc ->
145 getDOptsTc `thenNF_Tc` \ dflags ->
146 case lintUnfolding dflags src_loc in_scope_vars core_expr' of
147 (Nothing,_) -> returnTc (Just core_expr') -- ignore warnings
148 (Just fail_msg,_) -> failWithTc ((doc <+> text "failed Lint") $$ fail_msg)
150 doc = text "unfolding of" <+> ppr name
152 tcDelay :: RecTcEnv -> SDoc -> a -> TcM a -> NF_TcM a
153 tcDelay unf_env doc bad_ans thing_inside
155 recoverNF_Tc bad_value (
156 tcSetEnv unf_env thing_inside
159 -- The trace tells what wasn't available, for the benefit of
160 -- compiler hackers who want to improve it!
161 bad_value = getErrsTc `thenNF_Tc` \ (warns,errs) ->
162 returnNF_Tc (pprTrace "Failed:"
163 (hang doc 4 (pprBagOfErrors errs))
168 Variables in unfoldings
169 ~~~~~~~~~~~~~~~~~~~~~~~
170 ****** Inside here we use only the Global environment, even for locally bound variables.
171 ****** Why? Because we know all the types and want to bind them to real Ids.
174 tcVar :: Name -> TcM Id
176 = tcLookupGlobal_maybe name `thenNF_Tc` \ maybe_id ->
178 Just (AnId id) -> returnTc id ;
179 Nothing -> failWithTc (noDecl name)
182 noDecl name = hsep [ptext SLIT("Warning: no binding for"), ppr name]
188 tcCoreExpr :: UfExpr Name -> TcM CoreExpr
190 tcCoreExpr (UfType ty)
191 = tcIfaceType ty `thenTc` \ ty' ->
192 -- It might not be of kind type
195 tcCoreExpr (UfVar name)
196 = tcVar name `thenTc` \ id ->
199 tcCoreExpr (UfLit lit)
202 -- The dreaded lit-lits are also similar, except here the type
203 -- is read in explicitly rather than being implicit
204 tcCoreExpr (UfLitLit lit ty)
205 = tcIfaceType ty `thenTc` \ ty' ->
206 returnTc (Lit (MachLitLit lit ty'))
208 tcCoreExpr (UfFCall cc ty)
209 = tcIfaceType ty `thenTc` \ ty' ->
210 tcGetUnique `thenNF_Tc` \ u ->
211 returnTc (Var (mkFCallId u cc ty'))
213 tcCoreExpr (UfTuple (HsTupCon _ boxity arity) args)
214 = mapTc tcCoreExpr args `thenTc` \ args' ->
216 -- Put the missing type arguments back in
217 con_args = map (Type . exprType) args' ++ args'
219 returnTc (mkApps (Var con_id) con_args)
221 con_id = dataConId (tupleCon boxity arity)
224 tcCoreExpr (UfLam bndr body)
225 = tcCoreLamBndr bndr $ \ bndr' ->
226 tcCoreExpr body `thenTc` \ body' ->
227 returnTc (Lam bndr' body')
229 tcCoreExpr (UfApp fun arg)
230 = tcCoreExpr fun `thenTc` \ fun' ->
231 tcCoreExpr arg `thenTc` \ arg' ->
232 returnTc (App fun' arg')
234 tcCoreExpr (UfCase scrut case_bndr alts)
235 = tcCoreExpr scrut `thenTc` \ scrut' ->
237 scrut_ty = exprType scrut'
238 case_bndr' = mkLocalId case_bndr scrut_ty
240 tcExtendGlobalValEnv [case_bndr'] $
241 mapTc (tcCoreAlt scrut_ty) alts `thenTc` \ alts' ->
242 returnTc (Case scrut' case_bndr' alts')
244 tcCoreExpr (UfLet (UfNonRec bndr rhs) body)
245 = tcCoreExpr rhs `thenTc` \ rhs' ->
246 tcCoreValBndr bndr $ \ bndr' ->
247 tcCoreExpr body `thenTc` \ body' ->
248 returnTc (Let (NonRec bndr' rhs') body')
250 tcCoreExpr (UfLet (UfRec pairs) body)
251 = tcCoreValBndrs bndrs $ \ bndrs' ->
252 mapTc tcCoreExpr rhss `thenTc` \ rhss' ->
253 tcCoreExpr body `thenTc` \ body' ->
254 returnTc (Let (Rec (bndrs' `zip` rhss')) body')
256 (bndrs, rhss) = unzip pairs
258 tcCoreExpr (UfNote note expr)
259 = tcCoreExpr expr `thenTc` \ expr' ->
261 UfCoerce to_ty -> tcIfaceType to_ty `thenTc` \ to_ty' ->
262 returnTc (Note (Coerce to_ty'
263 (exprType expr')) expr')
264 UfInlineCall -> returnTc (Note InlineCall expr')
265 UfInlineMe -> returnTc (Note InlineMe expr')
266 UfSCC cc -> returnTc (Note (SCC cc) expr')
270 tcCoreLamBndr (UfValBinder name ty) thing_inside
271 = tcIfaceType ty `thenTc` \ ty' ->
273 id = mkLocalId name ty'
275 tcExtendGlobalValEnv [id] $
278 tcCoreLamBndr (UfTyBinder name kind) thing_inside
280 tyvar = mkTyVar name kind
282 tcExtendTyVarEnv [tyvar] (thing_inside tyvar)
284 tcCoreLamBndrs [] thing_inside = thing_inside []
285 tcCoreLamBndrs (b:bs) thing_inside
286 = tcCoreLamBndr b $ \ b' ->
287 tcCoreLamBndrs bs $ \ bs' ->
288 thing_inside (b':bs')
290 tcCoreValBndr (UfValBinder name ty) thing_inside
291 = tcIfaceType ty `thenTc` \ ty' ->
293 id = mkLocalId name ty'
295 tcExtendGlobalValEnv [id] $
298 tcCoreValBndrs bndrs thing_inside -- Expect them all to be ValBinders
299 = mapTc tcIfaceType tys `thenTc` \ tys' ->
301 ids = zipWithEqual "tcCoreValBndr" mkLocalId names tys'
303 tcExtendGlobalValEnv ids $
306 names = [name | UfValBinder name _ <- bndrs]
307 tys = [ty | UfValBinder _ ty <- bndrs]
311 tcCoreAlt scrut_ty (UfDefault, names, rhs)
312 = ASSERT( null names )
313 tcCoreExpr rhs `thenTc` \ rhs' ->
314 returnTc (DEFAULT, [], rhs')
316 tcCoreAlt scrut_ty (UfLitAlt lit, names, rhs)
317 = ASSERT( null names )
318 tcCoreExpr rhs `thenTc` \ rhs' ->
319 returnTc (LitAlt lit, [], rhs')
321 tcCoreAlt scrut_ty (UfLitLitAlt str ty, names, rhs)
322 = ASSERT( null names )
323 tcCoreExpr rhs `thenTc` \ rhs' ->
324 tcIfaceType ty `thenTc` \ ty' ->
325 returnTc (LitAlt (MachLitLit str ty'), [], rhs')
327 -- A case alternative is made quite a bit more complicated
328 -- by the fact that we omit type annotations because we can
329 -- work them out. True enough, but its not that easy!
330 tcCoreAlt scrut_ty alt@(con, names, rhs)
331 = tcConAlt con `thenTc` \ con ->
333 (main_tyvars, _, ex_tyvars, _, _, _) = dataConSig con
335 (tycon, inst_tys) = splitTyConApp scrut_ty -- NB: not tcSplitTyConApp
336 -- We are looking at Core here
337 ex_tyvars' = [mkTyVar name (tyVarKind tv) | (name,tv) <- names `zip` ex_tyvars]
338 ex_tys' = mkTyVarTys ex_tyvars'
339 arg_tys = dataConArgTys con (inst_tys ++ ex_tys')
340 id_names = dropList ex_tyvars names
343 | not (equalLength id_names arg_tys)
344 = pprPanic "tcCoreAlts" (ppr (con, names, rhs) $$
345 (ppr main_tyvars <+> ppr ex_tyvars) $$
349 = zipWithEqual "tcCoreAlts" mkLocalId id_names arg_tys
351 ASSERT( con `elem` tyConDataCons tycon && equalLength inst_tys main_tyvars )
352 tcExtendTyVarEnv ex_tyvars' $
353 tcExtendGlobalValEnv arg_ids $
354 tcCoreExpr rhs `thenTc` \ rhs' ->
355 returnTc (DataAlt con, ex_tyvars' ++ arg_ids, rhs')
358 tcConAlt :: UfConAlt Name -> TcM DataCon
359 tcConAlt (UfTupleAlt (HsTupCon _ boxity arity))
360 = returnTc (tupleCon boxity arity)
362 tcConAlt (UfDataAlt con_name)
363 = tcVar con_name `thenTc` \ con_id ->
364 returnTc (case isDataConWrapId_maybe con_id of
366 Nothing -> pprPanic "tcCoreAlt" (ppr con_id))
370 ifaceSigCtxt sig_name
371 = hsep [ptext SLIT("In an interface-file signature for"), ppr sig_name]