%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcIfaceSig]{Type checking of type signatures in interface files}
\begin{code}
-#include "HsVersions.h"
-
-module TcIfaceSig ( tcInterfaceSigs ) where
+module TcIfaceSig ( tcInterfaceSigs, tcVar, tcCoreExpr, tcCoreLamBndrs ) where
-import Ubiq
+#include "HsVersions.h"
+import HsSyn ( HsDecl(..), IfaceSig(..), HsTupCon(..) )
import TcMonad
-import TcMonoType ( tcPolyType )
-
-import HsSyn ( Sig(..), PolyType )
-import RnHsSyn ( RenamedSig(..) )
+import TcMonoType ( tcHsType )
+ -- NB: all the tyars in interface files are kinded,
+ -- so tcHsType will do the Right Thing without
+ -- having to mess about with zonking
-import CmdLineOpts ( opt_CompilingPrelude )
-import Id ( mkImported )
-import Name ( Name(..) )
-import Pretty
-import Util ( panic )
+import TcEnv ( TcEnv, tcExtendTyVarEnv,
+ tcExtendGlobalValEnv, tcSetEnv,
+ tcLookupGlobal_maybe, explicitLookupId, tcEnvIds
+ )
+import RnHsSyn ( RenamedHsDecl )
+import HsCore
+import Literal ( Literal(..) )
+import CoreSyn
+import CoreUtils ( exprType )
+import CoreUnfold
+import CoreLint ( lintUnfolding )
+import WorkWrap ( mkWrapper )
---import TcPragmas ( tcGenPragmas )
-import IdInfo ( noIdInfo )
-tcGenPragmas ty id ps = returnNF_Tc noIdInfo
-
+import Id ( Id, mkId, mkVanillaId, isDataConWrapId_maybe )
+import MkId ( mkCCallOpId )
+import IdInfo
+import DataCon ( dataConSig, dataConArgTys )
+import Type ( mkTyVarTys, splitAlgTyConApp_maybe, unUsgTy )
+import Var ( mkTyVar, tyVarKind )
+import Name ( Name, isLocallyDefined )
+import Demand ( wwLazy )
+import ErrUtils ( pprBagOfErrors )
+import Outputable
+import Util ( zipWithEqual )
+import HscTypes ( TyThing(..) )
\end{code}
Ultimately, type signatures in interfaces will have pragmatic
signatures.
\begin{code}
-tcInterfaceSigs :: [RenamedSig] -> TcM s [Id]
-
-tcInterfaceSigs [] = returnTc []
-
-tcInterfaceSigs (Sig name@(ValName uniq full_name) ty pragmas src_loc : sigs)
- = tcAddSrcLoc src_loc (
- tcPolyType ty `thenTc` \ sigma_ty ->
- fixTc ( \ rec_id ->
- tcGenPragmas (Just sigma_ty) rec_id pragmas
- `thenNF_Tc` \ id_info ->
- returnTc (mkImported uniq full_name sigma_ty id_info)
- )) `thenTc` \ id ->
- tcInterfaceSigs sigs `thenTc` \ sigs' ->
- returnTc (id:sigs')
-
-
-tcInterfaceSigs (Sig odd_name _ _ src_loc : sigs)
- = case odd_name of
- WiredInVal _ | opt_CompilingPrelude
- -> tcInterfaceSigs sigs
- _ -> tcAddSrcLoc src_loc $
- failTc (ifaceSigNameErr odd_name)
-
-ifaceSigNameErr name sty
- = ppHang (ppStr "Bad name in an interface type signature (a Prelude name?)")
- 4 (ppr sty name)
+tcInterfaceSigs :: TcEnv -- Envt to use when checking unfoldings
+ -> [RenamedHsDecl] -- Ignore non-sig-decls in these decls
+ -> TcM [Id]
+
+
+tcInterfaceSigs unf_env decls
+ = listTc [ do_one name ty id_infos src_loc
+ | SigD (IfaceSig name ty id_infos src_loc) <- decls]
+ where
+ in_scope_vars = filter isLocallyDefined (tcEnvIds unf_env)
+
+ do_one name ty id_infos src_loc
+ = tcAddSrcLoc src_loc $
+ tcAddErrCtxt (ifaceSigCtxt name) $
+ tcHsType ty `thenTc` \ sigma_ty ->
+ tcIdInfo unf_env in_scope_vars name
+ sigma_ty vanillaIdInfo id_infos `thenTc` \ id_info ->
+ returnTc (mkId name sigma_ty id_info)
+\end{code}
+
+\begin{code}
+tcIdInfo unf_env in_scope_vars name ty info info_ins
+ = foldlTc tcPrag vanillaIdInfo info_ins
+ where
+ tcPrag info (HsArity arity) = returnTc (info `setArityInfo` arity)
+ tcPrag info (HsNoCafRefs) = returnTc (info `setCafInfo` NoCafRefs)
+ tcPrag info HsCprInfo = returnTc (info `setCprInfo` ReturnsCPR)
+
+ tcPrag info (HsUnfold inline_prag expr)
+ = tcPragExpr unf_env name in_scope_vars expr `thenNF_Tc` \ maybe_expr' ->
+ let
+ -- maybe_expr doesn't get looked at if the unfolding
+ -- is never inspected; so the typecheck doesn't even happen
+ unfold_info = case maybe_expr' of
+ Nothing -> noUnfolding
+ Just expr' -> mkTopUnfolding expr'
+ info1 = info `setUnfoldingInfo` unfold_info
+ info2 = info1 `setInlinePragInfo` inline_prag
+ in
+ returnTc info2
+
+ tcPrag info (HsStrictness strict_info)
+ = returnTc (info `setStrictnessInfo` strict_info)
+
+ tcPrag info (HsWorker nm)
+ = tcWorkerInfo unf_env ty info nm
+\end{code}
+
+\begin{code}
+tcWorkerInfo unf_env ty info worker_name
+ | not (hasArity arity_info)
+ = pprPanic "Worker with no arity info" (ppr worker_name)
+
+ | otherwise
+ = uniqSMToTcM (mkWrapper ty arity demands res_bot cpr_info) `thenNF_Tc` \ wrap_fn ->
+ let
+ -- Watch out! We can't pull on unf_env too eagerly!
+ info' = case explicitLookupId unf_env worker_name of
+ Just worker_id -> info `setUnfoldingInfo` mkTopUnfolding (wrap_fn worker_id)
+ `setWorkerInfo` HasWorker worker_id arity
+
+ Nothing -> pprTrace "tcWorkerInfo failed:" (ppr worker_name) info
+ in
+ returnTc info'
+ where
+ -- We are relying here on arity, cpr and strictness info always appearing
+ -- before worker info, fingers crossed ....
+ arity_info = arityInfo info
+ arity = arityLowerBound arity_info
+ cpr_info = cprInfo info
+ (demands, res_bot) = case strictnessInfo info of
+ StrictnessInfo d r -> (d,r)
+ _ -> (take arity (repeat wwLazy),False) -- Noncommittal
+\end{code}
+
+For unfoldings we try to do the job lazily, so that we never type check
+an unfolding that isn't going to be looked at.
+
+\begin{code}
+tcPragExpr unf_env name in_scope_vars expr
+ = tcDelay unf_env doc $
+ tcCoreExpr expr `thenTc` \ core_expr' ->
+
+ -- Check for type consistency in the unfolding
+ tcGetSrcLoc `thenNF_Tc` \ src_loc ->
+ getDOptsTc `thenTc` \ dflags ->
+ case lintUnfolding dflags src_loc in_scope_vars core_expr' of
+ (Nothing,_) -> returnTc core_expr' -- ignore warnings
+ (Just fail_msg,_) -> failWithTc ((doc <+> text "failed Lint") $$ fail_msg)
+ where
+ doc = text "unfolding of" <+> ppr name
+
+tcDelay :: TcEnv -> SDoc -> TcM a -> NF_TcM (Maybe a)
+tcDelay unf_env doc thing_inside
+ = forkNF_Tc (
+ recoverNF_Tc bad_value (
+ tcSetEnv unf_env thing_inside `thenTc` \ r ->
+ returnTc (Just r)
+ ))
+ where
+ -- The trace tells what wasn't available, for the benefit of
+ -- compiler hackers who want to improve it!
+ bad_value = getErrsTc `thenNF_Tc` \ (warns,errs) ->
+ returnNF_Tc (pprTrace "Failed:"
+ (hang doc 4 (pprBagOfErrors errs))
+ Nothing)
\end{code}
+
+
+Variables in unfoldings
+~~~~~~~~~~~~~~~~~~~~~~~
+****** Inside here we use only the Global environment, even for locally bound variables.
+****** Why? Because we know all the types and want to bind them to real Ids.
+
+\begin{code}
+tcVar :: Name -> TcM Id
+tcVar name
+ = tcLookupGlobal_maybe name `thenNF_Tc` \ maybe_id ->
+ case maybe_id of {
+ Just (AnId id) -> returnTc id;
+ Nothing -> failWithTc (noDecl name)
+ }
+
+noDecl name = hsep [ptext SLIT("Warning: no binding for"), ppr name]
+\end{code}
+
+UfCore expressions.
+
+\begin{code}
+tcCoreExpr :: UfExpr Name -> TcM CoreExpr
+
+tcCoreExpr (UfType ty)
+ = tcHsType ty `thenTc` \ ty' ->
+ -- It might not be of kind type
+ returnTc (Type ty')
+
+tcCoreExpr (UfVar name)
+ = tcVar name `thenTc` \ id ->
+ returnTc (Var id)
+
+tcCoreExpr (UfLit lit)
+ = returnTc (Lit lit)
+
+-- The dreaded lit-lits are also similar, except here the type
+-- is read in explicitly rather than being implicit
+tcCoreExpr (UfLitLit lit ty)
+ = tcHsType ty `thenTc` \ ty' ->
+ returnTc (Lit (MachLitLit lit ty'))
+
+tcCoreExpr (UfCCall cc ty)
+ = tcHsType ty `thenTc` \ ty' ->
+ tcGetUnique `thenNF_Tc` \ u ->
+ returnTc (Var (mkCCallOpId u cc ty'))
+
+tcCoreExpr (UfTuple (HsTupCon name _) args)
+ = tcVar name `thenTc` \ con_id ->
+ mapTc tcCoreExpr args `thenTc` \ args' ->
+ let
+ -- Put the missing type arguments back in
+ con_args = map (Type . unUsgTy . exprType) args' ++ args'
+ in
+ returnTc (mkApps (Var con_id) con_args)
+
+tcCoreExpr (UfLam bndr body)
+ = tcCoreLamBndr bndr $ \ bndr' ->
+ tcCoreExpr body `thenTc` \ body' ->
+ returnTc (Lam bndr' body')
+
+tcCoreExpr (UfApp fun arg)
+ = tcCoreExpr fun `thenTc` \ fun' ->
+ tcCoreExpr arg `thenTc` \ arg' ->
+ returnTc (App fun' arg')
+
+tcCoreExpr (UfCase scrut case_bndr alts)
+ = tcCoreExpr scrut `thenTc` \ scrut' ->
+ let
+ scrut_ty = exprType scrut'
+ case_bndr' = mkVanillaId case_bndr scrut_ty
+ in
+ tcExtendGlobalValEnv [case_bndr'] $
+ mapTc (tcCoreAlt scrut_ty) alts `thenTc` \ alts' ->
+ returnTc (Case scrut' case_bndr' alts')
+
+tcCoreExpr (UfLet (UfNonRec bndr rhs) body)
+ = tcCoreExpr rhs `thenTc` \ rhs' ->
+ tcCoreValBndr bndr $ \ bndr' ->
+ tcCoreExpr body `thenTc` \ body' ->
+ returnTc (Let (NonRec bndr' rhs') body')
+
+tcCoreExpr (UfLet (UfRec pairs) body)
+ = tcCoreValBndrs bndrs $ \ bndrs' ->
+ mapTc tcCoreExpr rhss `thenTc` \ rhss' ->
+ tcCoreExpr body `thenTc` \ body' ->
+ returnTc (Let (Rec (bndrs' `zip` rhss')) body')
+ where
+ (bndrs, rhss) = unzip pairs
+
+tcCoreExpr (UfNote note expr)
+ = tcCoreExpr expr `thenTc` \ expr' ->
+ case note of
+ UfCoerce to_ty -> tcHsType to_ty `thenTc` \ to_ty' ->
+ returnTc (Note (Coerce (unUsgTy to_ty')
+ (unUsgTy (exprType expr'))) expr')
+ UfInlineCall -> returnTc (Note InlineCall expr')
+ UfInlineMe -> returnTc (Note InlineMe expr')
+ UfSCC cc -> returnTc (Note (SCC cc) expr')
+\end{code}
+
+\begin{code}
+tcCoreLamBndr (UfValBinder name ty) thing_inside
+ = tcHsType ty `thenTc` \ ty' ->
+ let
+ id = mkVanillaId name ty'
+ in
+ tcExtendGlobalValEnv [id] $
+ thing_inside id
+
+tcCoreLamBndr (UfTyBinder name kind) thing_inside
+ = let
+ tyvar = mkTyVar name kind
+ in
+ tcExtendTyVarEnv [tyvar] (thing_inside tyvar)
+
+tcCoreLamBndrs [] thing_inside = thing_inside []
+tcCoreLamBndrs (b:bs) thing_inside
+ = tcCoreLamBndr b $ \ b' ->
+ tcCoreLamBndrs bs $ \ bs' ->
+ thing_inside (b':bs')
+
+tcCoreValBndr (UfValBinder name ty) thing_inside
+ = tcHsType ty `thenTc` \ ty' ->
+ let
+ id = mkVanillaId name ty'
+ in
+ tcExtendGlobalValEnv [id] $
+ thing_inside id
+
+tcCoreValBndrs bndrs thing_inside -- Expect them all to be ValBinders
+ = mapTc tcHsType tys `thenTc` \ tys' ->
+ let
+ ids = zipWithEqual "tcCoreValBndr" mkVanillaId names tys'
+ in
+ tcExtendGlobalValEnv ids $
+ thing_inside ids
+ where
+ names = [name | UfValBinder name _ <- bndrs]
+ tys = [ty | UfValBinder _ ty <- bndrs]
+\end{code}
+
+\begin{code}
+tcCoreAlt scrut_ty (UfDefault, names, rhs)
+ = ASSERT( null names )
+ tcCoreExpr rhs `thenTc` \ rhs' ->
+ returnTc (DEFAULT, [], rhs')
+
+tcCoreAlt scrut_ty (UfLitAlt lit, names, rhs)
+ = ASSERT( null names )
+ tcCoreExpr rhs `thenTc` \ rhs' ->
+ returnTc (LitAlt lit, [], rhs')
+
+tcCoreAlt scrut_ty (UfLitLitAlt str ty, names, rhs)
+ = ASSERT( null names )
+ tcCoreExpr rhs `thenTc` \ rhs' ->
+ tcHsType ty `thenTc` \ ty' ->
+ returnTc (LitAlt (MachLitLit str ty'), [], rhs')
+
+-- A case alternative is made quite a bit more complicated
+-- by the fact that we omit type annotations because we can
+-- work them out. True enough, but its not that easy!
+tcCoreAlt scrut_ty alt@(UfDataAlt con_name, names, rhs)
+ = tcVar con_name `thenTc` \ con_id ->
+ let
+ con = case isDataConWrapId_maybe con_id of
+ Just con -> con
+ Nothing -> pprPanic "tcCoreAlt" (ppr con_id)
+
+ (main_tyvars, _, ex_tyvars, _, _, _) = dataConSig con
+
+ (_, inst_tys, cons) = case splitAlgTyConApp_maybe scrut_ty of
+ Just stuff -> stuff
+ Nothing -> pprPanic "tcCoreAlt" (ppr alt)
+ ex_tyvars' = [mkTyVar name (tyVarKind tv) | (name,tv) <- names `zip` ex_tyvars]
+ ex_tys' = mkTyVarTys ex_tyvars'
+ arg_tys = dataConArgTys con (inst_tys ++ ex_tys')
+ id_names = drop (length ex_tyvars) names
+ arg_ids
+#ifdef DEBUG
+ | length id_names /= length arg_tys
+ = pprPanic "tcCoreAlts" (ppr (con_name, names, rhs) $$
+ (ppr main_tyvars <+> ppr ex_tyvars) $$
+ ppr arg_tys)
+ | otherwise
+#endif
+ = zipWithEqual "tcCoreAlts" mkVanillaId id_names arg_tys
+ in
+ ASSERT( con `elem` cons && length inst_tys == length main_tyvars )
+ tcExtendTyVarEnv ex_tyvars' $
+ tcExtendGlobalValEnv arg_ids $
+ tcCoreExpr rhs `thenTc` \ rhs' ->
+ returnTc (DataAlt con, ex_tyvars' ++ arg_ids, rhs')
+\end{code}
+
+\begin{code}
+ifaceSigCtxt sig_name
+ = hsep [ptext SLIT("In an interface-file signature for"), ppr sig_name]
+\end{code}
+
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