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Diffstat (limited to 'compiler/typecheck/TcHsSyn.lhs')
| -rw-r--r-- | compiler/typecheck/TcHsSyn.lhs | 961 |
1 files changed, 961 insertions, 0 deletions
diff --git a/compiler/typecheck/TcHsSyn.lhs b/compiler/typecheck/TcHsSyn.lhs new file mode 100644 index 0000000000..6389f34aef --- /dev/null +++ b/compiler/typecheck/TcHsSyn.lhs @@ -0,0 +1,961 @@ +% +% (c) The AQUA Project, Glasgow University, 1996-1998 +% +\section[TcHsSyn]{Specialisations of the @HsSyn@ syntax for the typechecker} + +This module is an extension of @HsSyn@ syntax, for use in the type +checker. + +\begin{code} +module TcHsSyn ( + mkHsTyApp, mkHsDictApp, mkHsConApp, + mkHsTyLam, mkHsDictLam, mkHsDictLet, mkHsApp, + hsLitType, hsPatType, mkHsAppTy, mkSimpleHsAlt, + nlHsIntLit, mkVanillaTuplePat, + + + -- re-exported from TcMonad + TcId, TcIdSet, TcDictBinds, + + zonkTopDecls, zonkTopExpr, zonkTopLExpr, + zonkId, zonkTopBndrs + ) where + +#include "HsVersions.h" + +-- friends: +import HsSyn -- oodles of it + +-- others: +import Id ( idType, setIdType, Id ) + +import TcRnMonad +import Type ( Type ) +import TcType ( TcType, TcTyVar, mkTyVarTy, mkTyConApp, isImmutableTyVar ) +import Kind ( isLiftedTypeKind, liftedTypeKind, isSubKind ) +import qualified Type +import TcMType ( zonkQuantifiedTyVar, zonkType, zonkTcType, writeMetaTyVar ) +import TysPrim ( charPrimTy, intPrimTy, floatPrimTy, + doublePrimTy, addrPrimTy + ) +import TysWiredIn ( charTy, stringTy, intTy, + mkListTy, mkPArrTy, mkTupleTy, unitTy, + voidTy, listTyCon, tupleTyCon ) +import TyCon ( mkPrimTyCon, tyConKind, PrimRep(..) ) +import Kind ( splitKindFunTys ) +import Name ( Name, getOccName, mkInternalName, mkDerivedTyConOcc ) +import Var ( Var, isId, isLocalVar, tyVarKind ) +import VarSet +import VarEnv +import BasicTypes ( Boxity(..), IPName(..), ipNameName, mapIPName ) +import Maybes ( orElse ) +import Unique ( Uniquable(..) ) +import SrcLoc ( noSrcLoc, noLoc, Located(..), unLoc ) +import Util ( mapSnd ) +import Bag +import Outputable +\end{code} + + +%************************************************************************ +%* * +\subsection[mkFailurePair]{Code for pattern-matching and other failures} +%* * +%************************************************************************ + +Note: If @hsPatType@ doesn't bear a strong resemblance to @exprType@, +then something is wrong. +\begin{code} +mkVanillaTuplePat :: [OutPat Id] -> Boxity -> Pat Id +-- A vanilla tuple pattern simply gets its type from its sub-patterns +mkVanillaTuplePat pats box + = TuplePat pats box (mkTupleTy box (length pats) (map hsPatType pats)) + +hsPatType :: OutPat Id -> Type +hsPatType (L _ pat) = pat_type pat + +pat_type (ParPat pat) = hsPatType pat +pat_type (WildPat ty) = ty +pat_type (VarPat var) = idType var +pat_type (VarPatOut var _) = idType var +pat_type (BangPat pat) = hsPatType pat +pat_type (LazyPat pat) = hsPatType pat +pat_type (LitPat lit) = hsLitType lit +pat_type (AsPat var pat) = idType (unLoc var) +pat_type (ListPat _ ty) = mkListTy ty +pat_type (PArrPat _ ty) = mkPArrTy ty +pat_type (TuplePat pats box ty) = ty +pat_type (ConPatOut _ _ _ _ _ ty) = ty +pat_type (SigPatOut pat ty) = ty +pat_type (NPat lit _ _ ty) = ty +pat_type (NPlusKPat id _ _ _) = idType (unLoc id) +pat_type (DictPat ds ms) = case (ds ++ ms) of + [] -> unitTy + [d] -> idType d + ds -> mkTupleTy Boxed (length ds) (map idType ds) + + +hsLitType :: HsLit -> TcType +hsLitType (HsChar c) = charTy +hsLitType (HsCharPrim c) = charPrimTy +hsLitType (HsString str) = stringTy +hsLitType (HsStringPrim s) = addrPrimTy +hsLitType (HsInt i) = intTy +hsLitType (HsIntPrim i) = intPrimTy +hsLitType (HsInteger i ty) = ty +hsLitType (HsRat _ ty) = ty +hsLitType (HsFloatPrim f) = floatPrimTy +hsLitType (HsDoublePrim d) = doublePrimTy +\end{code} + + +%************************************************************************ +%* * +\subsection[BackSubst-HsBinds]{Running a substitution over @HsBinds@} +%* * +%************************************************************************ + +\begin{code} +-- zonkId is used *during* typechecking just to zonk the Id's type +zonkId :: TcId -> TcM TcId +zonkId id + = zonkTcType (idType id) `thenM` \ ty' -> + returnM (setIdType id ty') +\end{code} + +The rest of the zonking is done *after* typechecking. +The main zonking pass runs over the bindings + + a) to convert TcTyVars to TyVars etc, dereferencing any bindings etc + b) convert unbound TcTyVar to Void + c) convert each TcId to an Id by zonking its type + +The type variables are converted by binding mutable tyvars to immutable ones +and then zonking as normal. + +The Ids are converted by binding them in the normal Tc envt; that +way we maintain sharing; eg an Id is zonked at its binding site and they +all occurrences of that Id point to the common zonked copy + +It's all pretty boring stuff, because HsSyn is such a large type, and +the environment manipulation is tiresome. + +\begin{code} +data ZonkEnv = ZonkEnv (TcType -> TcM Type) -- How to zonk a type + (IdEnv Id) -- What variables are in scope + -- Maps an Id to its zonked version; both have the same Name + -- Is only consulted lazily; hence knot-tying + +emptyZonkEnv = ZonkEnv zonkTypeZapping emptyVarEnv + +extendZonkEnv :: ZonkEnv -> [Id] -> ZonkEnv +extendZonkEnv (ZonkEnv zonk_ty env) ids + = ZonkEnv zonk_ty (extendVarEnvList env [(id,id) | id <- ids]) + +extendZonkEnv1 :: ZonkEnv -> Id -> ZonkEnv +extendZonkEnv1 (ZonkEnv zonk_ty env) id + = ZonkEnv zonk_ty (extendVarEnv env id id) + +setZonkType :: ZonkEnv -> (TcType -> TcM Type) -> ZonkEnv +setZonkType (ZonkEnv _ env) zonk_ty = ZonkEnv zonk_ty env + +zonkEnvIds :: ZonkEnv -> [Id] +zonkEnvIds (ZonkEnv _ env) = varEnvElts env + +zonkIdOcc :: ZonkEnv -> TcId -> Id +-- Ids defined in this module should be in the envt; +-- ignore others. (Actually, data constructors are also +-- not LocalVars, even when locally defined, but that is fine.) +-- (Also foreign-imported things aren't currently in the ZonkEnv; +-- that's ok because they don't need zonking.) +-- +-- Actually, Template Haskell works in 'chunks' of declarations, and +-- an earlier chunk won't be in the 'env' that the zonking phase +-- carries around. Instead it'll be in the tcg_gbl_env, already fully +-- zonked. There's no point in looking it up there (except for error +-- checking), and it's not conveniently to hand; hence the simple +-- 'orElse' case in the LocalVar branch. +-- +-- Even without template splices, in module Main, the checking of +-- 'main' is done as a separate chunk. +zonkIdOcc (ZonkEnv zonk_ty env) id + | isLocalVar id = lookupVarEnv env id `orElse` id + | otherwise = id + +zonkIdOccs env ids = map (zonkIdOcc env) ids + +-- zonkIdBndr is used *after* typechecking to get the Id's type +-- to its final form. The TyVarEnv give +zonkIdBndr :: ZonkEnv -> TcId -> TcM Id +zonkIdBndr env id + = zonkTcTypeToType env (idType id) `thenM` \ ty' -> + returnM (setIdType id ty') + +zonkIdBndrs :: ZonkEnv -> [TcId] -> TcM [Id] +zonkIdBndrs env ids = mappM (zonkIdBndr env) ids + +zonkTopBndrs :: [TcId] -> TcM [Id] +zonkTopBndrs ids = zonkIdBndrs emptyZonkEnv ids +\end{code} + + +\begin{code} +zonkTopExpr :: HsExpr TcId -> TcM (HsExpr Id) +zonkTopExpr e = zonkExpr emptyZonkEnv e + +zonkTopLExpr :: LHsExpr TcId -> TcM (LHsExpr Id) +zonkTopLExpr e = zonkLExpr emptyZonkEnv e + +zonkTopDecls :: LHsBinds TcId -> [LRuleDecl TcId] -> [LForeignDecl TcId] + -> TcM ([Id], + Bag (LHsBind Id), + [LForeignDecl Id], + [LRuleDecl Id]) +zonkTopDecls binds rules fords + = do { (env, binds') <- zonkRecMonoBinds emptyZonkEnv binds + -- Top level is implicitly recursive + ; rules' <- zonkRules env rules + ; fords' <- zonkForeignExports env fords + ; return (zonkEnvIds env, binds', fords', rules') } + +--------------------------------------------- +zonkLocalBinds :: ZonkEnv -> HsLocalBinds TcId -> TcM (ZonkEnv, HsLocalBinds Id) +zonkLocalBinds env EmptyLocalBinds + = return (env, EmptyLocalBinds) + +zonkLocalBinds env (HsValBinds binds) + = do { (env1, new_binds) <- zonkValBinds env binds + ; return (env1, HsValBinds new_binds) } + +zonkLocalBinds env (HsIPBinds (IPBinds binds dict_binds)) + = mappM (wrapLocM zonk_ip_bind) binds `thenM` \ new_binds -> + let + env1 = extendZonkEnv env [ipNameName n | L _ (IPBind n _) <- new_binds] + in + zonkRecMonoBinds env1 dict_binds `thenM` \ (env2, new_dict_binds) -> + returnM (env2, HsIPBinds (IPBinds new_binds new_dict_binds)) + where + zonk_ip_bind (IPBind n e) + = mapIPNameTc (zonkIdBndr env) n `thenM` \ n' -> + zonkLExpr env e `thenM` \ e' -> + returnM (IPBind n' e') + + +--------------------------------------------- +zonkValBinds :: ZonkEnv -> HsValBinds TcId -> TcM (ZonkEnv, HsValBinds Id) +zonkValBinds env bs@(ValBindsIn _ _) + = panic "zonkValBinds" -- Not in typechecker output +zonkValBinds env (ValBindsOut binds sigs) + = do { (env1, new_binds) <- go env binds + ; return (env1, ValBindsOut new_binds sigs) } + where + go env [] = return (env, []) + go env ((r,b):bs) = do { (env1, b') <- zonkRecMonoBinds env b + ; (env2, bs') <- go env1 bs + ; return (env2, (r,b'):bs') } + +--------------------------------------------- +zonkRecMonoBinds :: ZonkEnv -> LHsBinds TcId -> TcM (ZonkEnv, LHsBinds Id) +zonkRecMonoBinds env binds + = fixM (\ ~(_, new_binds) -> do + { let env1 = extendZonkEnv env (collectHsBindBinders new_binds) + ; binds' <- zonkMonoBinds env1 binds + ; return (env1, binds') }) + +--------------------------------------------- +zonkMonoBinds :: ZonkEnv -> LHsBinds TcId -> TcM (LHsBinds Id) +zonkMonoBinds env binds = mapBagM (wrapLocM (zonk_bind env)) binds + +zonk_bind :: ZonkEnv -> HsBind TcId -> TcM (HsBind Id) +zonk_bind env bind@(PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty}) + = do { (_env, new_pat) <- zonkPat env pat -- Env already extended + ; new_grhss <- zonkGRHSs env grhss + ; new_ty <- zonkTcTypeToType env ty + ; return (bind { pat_lhs = new_pat, pat_rhs = new_grhss, pat_rhs_ty = new_ty }) } + +zonk_bind env (VarBind { var_id = var, var_rhs = expr }) + = zonkIdBndr env var `thenM` \ new_var -> + zonkLExpr env expr `thenM` \ new_expr -> + returnM (VarBind { var_id = new_var, var_rhs = new_expr }) + +zonk_bind env bind@(FunBind { fun_id = var, fun_matches = ms, fun_co_fn = co_fn }) + = wrapLocM (zonkIdBndr env) var `thenM` \ new_var -> + zonkCoFn env co_fn `thenM` \ (env1, new_co_fn) -> + zonkMatchGroup env1 ms `thenM` \ new_ms -> + returnM (bind { fun_id = new_var, fun_matches = new_ms, fun_co_fn = new_co_fn }) + +zonk_bind env (AbsBinds { abs_tvs = tyvars, abs_dicts = dicts, + abs_exports = exports, abs_binds = val_binds }) + = ASSERT( all isImmutableTyVar tyvars ) + zonkIdBndrs env dicts `thenM` \ new_dicts -> + fixM (\ ~(new_val_binds, _) -> + let + env1 = extendZonkEnv env new_dicts + env2 = extendZonkEnv env1 (collectHsBindBinders new_val_binds) + in + zonkMonoBinds env2 val_binds `thenM` \ new_val_binds -> + mappM (zonkExport env2) exports `thenM` \ new_exports -> + returnM (new_val_binds, new_exports) + ) `thenM` \ (new_val_bind, new_exports) -> + returnM (AbsBinds { abs_tvs = tyvars, abs_dicts = new_dicts, + abs_exports = new_exports, abs_binds = new_val_bind }) + where + zonkExport env (tyvars, global, local, prags) + = zonkIdBndr env global `thenM` \ new_global -> + mapM zonk_prag prags `thenM` \ new_prags -> + returnM (tyvars, new_global, zonkIdOcc env local, new_prags) + zonk_prag prag@(InlinePrag {}) = return prag + zonk_prag (SpecPrag expr ty ds inl) = do { expr' <- zonkExpr env expr + ; ty' <- zonkTcTypeToType env ty + ; let ds' = zonkIdOccs env ds + ; return (SpecPrag expr' ty' ds' inl) } +\end{code} + +%************************************************************************ +%* * +\subsection[BackSubst-Match-GRHSs]{Match and GRHSs} +%* * +%************************************************************************ + +\begin{code} +zonkMatchGroup :: ZonkEnv -> MatchGroup TcId-> TcM (MatchGroup Id) +zonkMatchGroup env (MatchGroup ms ty) + = do { ms' <- mapM (zonkMatch env) ms + ; ty' <- zonkTcTypeToType env ty + ; return (MatchGroup ms' ty') } + +zonkMatch :: ZonkEnv -> LMatch TcId-> TcM (LMatch Id) +zonkMatch env (L loc (Match pats _ grhss)) + = do { (env1, new_pats) <- zonkPats env pats + ; new_grhss <- zonkGRHSs env1 grhss + ; return (L loc (Match new_pats Nothing new_grhss)) } + +------------------------------------------------------------------------- +zonkGRHSs :: ZonkEnv -> GRHSs TcId -> TcM (GRHSs Id) + +zonkGRHSs env (GRHSs grhss binds) + = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) -> + let + zonk_grhs (GRHS guarded rhs) + = zonkStmts new_env guarded `thenM` \ (env2, new_guarded) -> + zonkLExpr env2 rhs `thenM` \ new_rhs -> + returnM (GRHS new_guarded new_rhs) + in + mappM (wrapLocM zonk_grhs) grhss `thenM` \ new_grhss -> + returnM (GRHSs new_grhss new_binds) +\end{code} + +%************************************************************************ +%* * +\subsection[BackSubst-HsExpr]{Running a zonkitution over a TypeCheckedExpr} +%* * +%************************************************************************ + +\begin{code} +zonkLExprs :: ZonkEnv -> [LHsExpr TcId] -> TcM [LHsExpr Id] +zonkLExpr :: ZonkEnv -> LHsExpr TcId -> TcM (LHsExpr Id) +zonkExpr :: ZonkEnv -> HsExpr TcId -> TcM (HsExpr Id) + +zonkLExprs env exprs = mappM (zonkLExpr env) exprs +zonkLExpr env expr = wrapLocM (zonkExpr env) expr + +zonkExpr env (HsVar id) + = returnM (HsVar (zonkIdOcc env id)) + +zonkExpr env (HsIPVar id) + = returnM (HsIPVar (mapIPName (zonkIdOcc env) id)) + +zonkExpr env (HsLit (HsRat f ty)) + = zonkTcTypeToType env ty `thenM` \ new_ty -> + returnM (HsLit (HsRat f new_ty)) + +zonkExpr env (HsLit lit) + = returnM (HsLit lit) + +zonkExpr env (HsOverLit lit) + = do { lit' <- zonkOverLit env lit + ; return (HsOverLit lit') } + +zonkExpr env (HsLam matches) + = zonkMatchGroup env matches `thenM` \ new_matches -> + returnM (HsLam new_matches) + +zonkExpr env (HsApp e1 e2) + = zonkLExpr env e1 `thenM` \ new_e1 -> + zonkLExpr env e2 `thenM` \ new_e2 -> + returnM (HsApp new_e1 new_e2) + +zonkExpr env (HsBracketOut body bs) + = mappM zonk_b bs `thenM` \ bs' -> + returnM (HsBracketOut body bs') + where + zonk_b (n,e) = zonkLExpr env e `thenM` \ e' -> + returnM (n,e') + +zonkExpr env (HsSpliceE s) = WARN( True, ppr s ) -- Should not happen + returnM (HsSpliceE s) + +zonkExpr env (OpApp e1 op fixity e2) + = zonkLExpr env e1 `thenM` \ new_e1 -> + zonkLExpr env op `thenM` \ new_op -> + zonkLExpr env e2 `thenM` \ new_e2 -> + returnM (OpApp new_e1 new_op fixity new_e2) + +zonkExpr env (NegApp expr op) + = zonkLExpr env expr `thenM` \ new_expr -> + zonkExpr env op `thenM` \ new_op -> + returnM (NegApp new_expr new_op) + +zonkExpr env (HsPar e) + = zonkLExpr env e `thenM` \new_e -> + returnM (HsPar new_e) + +zonkExpr env (SectionL expr op) + = zonkLExpr env expr `thenM` \ new_expr -> + zonkLExpr env op `thenM` \ new_op -> + returnM (SectionL new_expr new_op) + +zonkExpr env (SectionR op expr) + = zonkLExpr env op `thenM` \ new_op -> + zonkLExpr env expr `thenM` \ new_expr -> + returnM (SectionR new_op new_expr) + +zonkExpr env (HsCase expr ms) + = zonkLExpr env expr `thenM` \ new_expr -> + zonkMatchGroup env ms `thenM` \ new_ms -> + returnM (HsCase new_expr new_ms) + +zonkExpr env (HsIf e1 e2 e3) + = zonkLExpr env e1 `thenM` \ new_e1 -> + zonkLExpr env e2 `thenM` \ new_e2 -> + zonkLExpr env e3 `thenM` \ new_e3 -> + returnM (HsIf new_e1 new_e2 new_e3) + +zonkExpr env (HsLet binds expr) + = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) -> + zonkLExpr new_env expr `thenM` \ new_expr -> + returnM (HsLet new_binds new_expr) + +zonkExpr env (HsDo do_or_lc stmts body ty) + = zonkStmts env stmts `thenM` \ (new_env, new_stmts) -> + zonkLExpr new_env body `thenM` \ new_body -> + zonkTcTypeToType env ty `thenM` \ new_ty -> + returnM (HsDo (zonkDo env do_or_lc) + new_stmts new_body new_ty) + +zonkExpr env (ExplicitList ty exprs) + = zonkTcTypeToType env ty `thenM` \ new_ty -> + zonkLExprs env exprs `thenM` \ new_exprs -> + returnM (ExplicitList new_ty new_exprs) + +zonkExpr env (ExplicitPArr ty exprs) + = zonkTcTypeToType env ty `thenM` \ new_ty -> + zonkLExprs env exprs `thenM` \ new_exprs -> + returnM (ExplicitPArr new_ty new_exprs) + +zonkExpr env (ExplicitTuple exprs boxed) + = zonkLExprs env exprs `thenM` \ new_exprs -> + returnM (ExplicitTuple new_exprs boxed) + +zonkExpr env (RecordCon data_con con_expr rbinds) + = zonkExpr env con_expr `thenM` \ new_con_expr -> + zonkRbinds env rbinds `thenM` \ new_rbinds -> + returnM (RecordCon data_con new_con_expr new_rbinds) + +zonkExpr env (RecordUpd expr rbinds in_ty out_ty) + = zonkLExpr env expr `thenM` \ new_expr -> + zonkTcTypeToType env in_ty `thenM` \ new_in_ty -> + zonkTcTypeToType env out_ty `thenM` \ new_out_ty -> + zonkRbinds env rbinds `thenM` \ new_rbinds -> + returnM (RecordUpd new_expr new_rbinds new_in_ty new_out_ty) + +zonkExpr env (ExprWithTySigOut e ty) + = do { e' <- zonkLExpr env e + ; return (ExprWithTySigOut e' ty) } + +zonkExpr env (ExprWithTySig _ _) = panic "zonkExpr env:ExprWithTySig" + +zonkExpr env (ArithSeq expr info) + = zonkExpr env expr `thenM` \ new_expr -> + zonkArithSeq env info `thenM` \ new_info -> + returnM (ArithSeq new_expr new_info) + +zonkExpr env (PArrSeq expr info) + = zonkExpr env expr `thenM` \ new_expr -> + zonkArithSeq env info `thenM` \ new_info -> + returnM (PArrSeq new_expr new_info) + +zonkExpr env (HsSCC lbl expr) + = zonkLExpr env expr `thenM` \ new_expr -> + returnM (HsSCC lbl new_expr) + +-- hdaume: core annotations +zonkExpr env (HsCoreAnn lbl expr) + = zonkLExpr env expr `thenM` \ new_expr -> + returnM (HsCoreAnn lbl new_expr) + +zonkExpr env (TyLam tyvars expr) + = ASSERT( all isImmutableTyVar tyvars ) + zonkLExpr env expr `thenM` \ new_expr -> + returnM (TyLam tyvars new_expr) + +zonkExpr env (TyApp expr tys) + = zonkLExpr env expr `thenM` \ new_expr -> + zonkTcTypeToTypes env tys `thenM` \ new_tys -> + returnM (TyApp new_expr new_tys) + +zonkExpr env (DictLam dicts expr) + = zonkIdBndrs env dicts `thenM` \ new_dicts -> + let + env1 = extendZonkEnv env new_dicts + in + zonkLExpr env1 expr `thenM` \ new_expr -> + returnM (DictLam new_dicts new_expr) + +zonkExpr env (DictApp expr dicts) + = zonkLExpr env expr `thenM` \ new_expr -> + returnM (DictApp new_expr (zonkIdOccs env dicts)) + +-- arrow notation extensions +zonkExpr env (HsProc pat body) + = do { (env1, new_pat) <- zonkPat env pat + ; new_body <- zonkCmdTop env1 body + ; return (HsProc new_pat new_body) } + +zonkExpr env (HsArrApp e1 e2 ty ho rl) + = zonkLExpr env e1 `thenM` \ new_e1 -> + zonkLExpr env e2 `thenM` \ new_e2 -> + zonkTcTypeToType env ty `thenM` \ new_ty -> + returnM (HsArrApp new_e1 new_e2 new_ty ho rl) + +zonkExpr env (HsArrForm op fixity args) + = zonkLExpr env op `thenM` \ new_op -> + mappM (zonkCmdTop env) args `thenM` \ new_args -> + returnM (HsArrForm new_op fixity new_args) + +zonkExpr env (HsCoerce co_fn expr) + = zonkCoFn env co_fn `thenM` \ (env1, new_co_fn) -> + zonkExpr env1 expr `thenM` \ new_expr -> + return (HsCoerce new_co_fn new_expr) + +zonkExpr env other = pprPanic "zonkExpr" (ppr other) + +zonkCmdTop :: ZonkEnv -> LHsCmdTop TcId -> TcM (LHsCmdTop Id) +zonkCmdTop env cmd = wrapLocM (zonk_cmd_top env) cmd + +zonk_cmd_top env (HsCmdTop cmd stack_tys ty ids) + = zonkLExpr env cmd `thenM` \ new_cmd -> + zonkTcTypeToTypes env stack_tys `thenM` \ new_stack_tys -> + zonkTcTypeToType env ty `thenM` \ new_ty -> + mapSndM (zonkExpr env) ids `thenM` \ new_ids -> + returnM (HsCmdTop new_cmd new_stack_tys new_ty new_ids) + +------------------------------------------------------------------------- +zonkCoFn :: ZonkEnv -> ExprCoFn -> TcM (ZonkEnv, ExprCoFn) +zonkCoFn env CoHole = return (env, CoHole) +zonkCoFn env (CoCompose c1 c2) = do { (env1, c1') <- zonkCoFn env c1 + ; (env2, c2') <- zonkCoFn env1 c2 + ; return (env2, CoCompose c1' c2') } +zonkCoFn env (CoLams ids c) = do { ids' <- zonkIdBndrs env ids + ; let env1 = extendZonkEnv env ids' + ; (env2, c') <- zonkCoFn env1 c + ; return (env2, CoLams ids' c') } +zonkCoFn env (CoTyLams tvs c) = ASSERT( all isImmutableTyVar tvs ) + do { (env1, c') <- zonkCoFn env c + ; return (env1, CoTyLams tvs c') } +zonkCoFn env (CoApps c ids) = do { (env1, c') <- zonkCoFn env c + ; return (env1, CoApps c' (zonkIdOccs env ids)) } +zonkCoFn env (CoTyApps c tys) = do { tys' <- zonkTcTypeToTypes env tys + ; (env1, c') <- zonkCoFn env c + ; return (env1, CoTyApps c' tys') } +zonkCoFn env (CoLet bs c) = do { (env1, bs') <- zonkRecMonoBinds env bs + ; (env2, c') <- zonkCoFn env1 c + ; return (env2, CoLet bs' c') } + + +------------------------------------------------------------------------- +zonkDo :: ZonkEnv -> HsStmtContext Name -> HsStmtContext Name +-- Only used for 'do', so the only Ids are in a MDoExpr table +zonkDo env (MDoExpr tbl) = MDoExpr (mapSnd (zonkIdOcc env) tbl) +zonkDo env do_or_lc = do_or_lc + +------------------------------------------------------------------------- +zonkOverLit :: ZonkEnv -> HsOverLit TcId -> TcM (HsOverLit Id) +zonkOverLit env (HsIntegral i e) + = do { e' <- zonkExpr env e; return (HsIntegral i e') } +zonkOverLit env (HsFractional r e) + = do { e' <- zonkExpr env e; return (HsFractional r e') } + +------------------------------------------------------------------------- +zonkArithSeq :: ZonkEnv -> ArithSeqInfo TcId -> TcM (ArithSeqInfo Id) + +zonkArithSeq env (From e) + = zonkLExpr env e `thenM` \ new_e -> + returnM (From new_e) + +zonkArithSeq env (FromThen e1 e2) + = zonkLExpr env e1 `thenM` \ new_e1 -> + zonkLExpr env e2 `thenM` \ new_e2 -> + returnM (FromThen new_e1 new_e2) + +zonkArithSeq env (FromTo e1 e2) + = zonkLExpr env e1 `thenM` \ new_e1 -> + zonkLExpr env e2 `thenM` \ new_e2 -> + returnM (FromTo new_e1 new_e2) + +zonkArithSeq env (FromThenTo e1 e2 e3) + = zonkLExpr env e1 `thenM` \ new_e1 -> + zonkLExpr env e2 `thenM` \ new_e2 -> + zonkLExpr env e3 `thenM` \ new_e3 -> + returnM (FromThenTo new_e1 new_e2 new_e3) + + +------------------------------------------------------------------------- +zonkStmts :: ZonkEnv -> [LStmt TcId] -> TcM (ZonkEnv, [LStmt Id]) +zonkStmts env [] = return (env, []) +zonkStmts env (s:ss) = do { (env1, s') <- wrapLocSndM (zonkStmt env) s + ; (env2, ss') <- zonkStmts env1 ss + ; return (env2, s' : ss') } + +zonkStmt :: ZonkEnv -> Stmt TcId -> TcM (ZonkEnv, Stmt Id) +zonkStmt env (ParStmt stmts_w_bndrs) + = mappM zonk_branch stmts_w_bndrs `thenM` \ new_stmts_w_bndrs -> + let + new_binders = concat (map snd new_stmts_w_bndrs) + env1 = extendZonkEnv env new_binders + in + return (env1, ParStmt new_stmts_w_bndrs) + where + zonk_branch (stmts, bndrs) = zonkStmts env stmts `thenM` \ (env1, new_stmts) -> + returnM (new_stmts, zonkIdOccs env1 bndrs) + +zonkStmt env (RecStmt segStmts lvs rvs rets binds) + = zonkIdBndrs env rvs `thenM` \ new_rvs -> + let + env1 = extendZonkEnv env new_rvs + in + zonkStmts env1 segStmts `thenM` \ (env2, new_segStmts) -> + -- Zonk the ret-expressions in an envt that + -- has the polymorphic bindings in the envt + mapM (zonkExpr env2) rets `thenM` \ new_rets -> + let + new_lvs = zonkIdOccs env2 lvs + env3 = extendZonkEnv env new_lvs -- Only the lvs are needed + in + zonkRecMonoBinds env3 binds `thenM` \ (env4, new_binds) -> + returnM (env4, RecStmt new_segStmts new_lvs new_rvs new_rets new_binds) + +zonkStmt env (ExprStmt expr then_op ty) + = zonkLExpr env expr `thenM` \ new_expr -> + zonkExpr env then_op `thenM` \ new_then -> + zonkTcTypeToType env ty `thenM` \ new_ty -> + returnM (env, ExprStmt new_expr new_then new_ty) + +zonkStmt env (LetStmt binds) + = zonkLocalBinds env binds `thenM` \ (env1, new_binds) -> + returnM (env1, LetStmt new_binds) + +zonkStmt env (BindStmt pat expr bind_op fail_op) + = do { new_expr <- zonkLExpr env expr + ; (env1, new_pat) <- zonkPat env pat + ; new_bind <- zonkExpr env bind_op + ; new_fail <- zonkExpr env fail_op + ; return (env1, BindStmt new_pat new_expr new_bind new_fail) } + + +------------------------------------------------------------------------- +zonkRbinds :: ZonkEnv -> HsRecordBinds TcId -> TcM (HsRecordBinds Id) + +zonkRbinds env rbinds + = mappM zonk_rbind rbinds + where + zonk_rbind (field, expr) + = zonkLExpr env expr `thenM` \ new_expr -> + returnM (fmap (zonkIdOcc env) field, new_expr) + +------------------------------------------------------------------------- +mapIPNameTc :: (a -> TcM b) -> IPName a -> TcM (IPName b) +mapIPNameTc f (Dupable n) = f n `thenM` \ r -> returnM (Dupable r) +mapIPNameTc f (Linear n) = f n `thenM` \ r -> returnM (Linear r) +\end{code} + + +%************************************************************************ +%* * +\subsection[BackSubst-Pats]{Patterns} +%* * +%************************************************************************ + +\begin{code} +zonkPat :: ZonkEnv -> OutPat TcId -> TcM (ZonkEnv, OutPat Id) +-- Extend the environment as we go, because it's possible for one +-- pattern to bind something that is used in another (inside or +-- to the right) +zonkPat env pat = wrapLocSndM (zonk_pat env) pat + +zonk_pat env (ParPat p) + = do { (env', p') <- zonkPat env p + ; return (env', ParPat p') } + +zonk_pat env (WildPat ty) + = do { ty' <- zonkTcTypeToType env ty + ; return (env, WildPat ty') } + +zonk_pat env (VarPat v) + = do { v' <- zonkIdBndr env v + ; return (extendZonkEnv1 env v', VarPat v') } + +zonk_pat env (VarPatOut v binds) + = do { v' <- zonkIdBndr env v + ; (env', binds') <- zonkRecMonoBinds (extendZonkEnv1 env v') binds + ; returnM (env', VarPatOut v' binds') } + +zonk_pat env (LazyPat pat) + = do { (env', pat') <- zonkPat env pat + ; return (env', LazyPat pat') } + +zonk_pat env (BangPat pat) + = do { (env', pat') <- zonkPat env pat + ; return (env', BangPat pat') } + +zonk_pat env (AsPat (L loc v) pat) + = do { v' <- zonkIdBndr env v + ; (env', pat') <- zonkPat (extendZonkEnv1 env v') pat + ; return (env', AsPat (L loc v') pat') } + +zonk_pat env (ListPat pats ty) + = do { ty' <- zonkTcTypeToType env ty + ; (env', pats') <- zonkPats env pats + ; return (env', ListPat pats' ty') } + +zonk_pat env (PArrPat pats ty) + = do { ty' <- zonkTcTypeToType env ty + ; (env', pats') <- zonkPats env pats + ; return (env', PArrPat pats' ty') } + +zonk_pat env (TuplePat pats boxed ty) + = do { ty' <- zonkTcTypeToType env ty + ; (env', pats') <- zonkPats env pats + ; return (env', TuplePat pats' boxed ty') } + +zonk_pat env (ConPatOut n tvs dicts binds stuff ty) + = ASSERT( all isImmutableTyVar tvs ) + do { new_ty <- zonkTcTypeToType env ty + ; new_dicts <- zonkIdBndrs env dicts + ; let env1 = extendZonkEnv env new_dicts + ; (env2, new_binds) <- zonkRecMonoBinds env1 binds + ; (env', new_stuff) <- zonkConStuff env2 stuff + ; returnM (env', ConPatOut n tvs new_dicts new_binds new_stuff new_ty) } + +zonk_pat env (LitPat lit) = return (env, LitPat lit) + +zonk_pat env (SigPatOut pat ty) + = do { ty' <- zonkTcTypeToType env ty + ; (env', pat') <- zonkPat env pat + ; return (env', SigPatOut pat' ty') } + +zonk_pat env (NPat lit mb_neg eq_expr ty) + = do { lit' <- zonkOverLit env lit + ; mb_neg' <- case mb_neg of + Nothing -> return Nothing + Just neg -> do { neg' <- zonkExpr env neg + ; return (Just neg') } + ; eq_expr' <- zonkExpr env eq_expr + ; ty' <- zonkTcTypeToType env ty + ; return (env, NPat lit' mb_neg' eq_expr' ty') } + +zonk_pat env (NPlusKPat (L loc n) lit e1 e2) + = do { n' <- zonkIdBndr env n + ; lit' <- zonkOverLit env lit + ; e1' <- zonkExpr env e1 + ; e2' <- zonkExpr env e2 + ; return (extendZonkEnv1 env n', NPlusKPat (L loc n') lit' e1' e2') } + +zonk_pat env (DictPat ds ms) + = do { ds' <- zonkIdBndrs env ds + ; ms' <- zonkIdBndrs env ms + ; return (extendZonkEnv env (ds' ++ ms'), DictPat ds' ms') } + +--------------------------- +zonkConStuff env (PrefixCon pats) + = do { (env', pats') <- zonkPats env pats + ; return (env', PrefixCon pats') } + +zonkConStuff env (InfixCon p1 p2) + = do { (env1, p1') <- zonkPat env p1 + ; (env', p2') <- zonkPat env1 p2 + ; return (env', InfixCon p1' p2') } + +zonkConStuff env (RecCon rpats) + = do { (env', pats') <- zonkPats env pats + ; returnM (env', RecCon (fields `zip` pats')) } + where + (fields, pats) = unzip rpats + +--------------------------- +zonkPats env [] = return (env, []) +zonkPats env (pat:pats) = do { (env1, pat') <- zonkPat env pat + ; (env', pats') <- zonkPats env1 pats + ; return (env', pat':pats') } +\end{code} + +%************************************************************************ +%* * +\subsection[BackSubst-Foreign]{Foreign exports} +%* * +%************************************************************************ + + +\begin{code} +zonkForeignExports :: ZonkEnv -> [LForeignDecl TcId] -> TcM [LForeignDecl Id] +zonkForeignExports env ls = mappM (wrapLocM (zonkForeignExport env)) ls + +zonkForeignExport :: ZonkEnv -> ForeignDecl TcId -> TcM (ForeignDecl Id) +zonkForeignExport env (ForeignExport i hs_ty spec isDeprec) = + returnM (ForeignExport (fmap (zonkIdOcc env) i) undefined spec isDeprec) +zonkForeignExport env for_imp + = returnM for_imp -- Foreign imports don't need zonking +\end{code} + +\begin{code} +zonkRules :: ZonkEnv -> [LRuleDecl TcId] -> TcM [LRuleDecl Id] +zonkRules env rs = mappM (wrapLocM (zonkRule env)) rs + +zonkRule :: ZonkEnv -> RuleDecl TcId -> TcM (RuleDecl Id) +zonkRule env (HsRule name act (vars::[RuleBndr TcId]) lhs fv_lhs rhs fv_rhs) + = mappM zonk_bndr vars `thenM` \ new_bndrs -> + newMutVar emptyVarSet `thenM` \ unbound_tv_set -> + let + env_rhs = extendZonkEnv env [id | b <- new_bndrs, let id = unLoc b, isId id] + -- Type variables don't need an envt + -- They are bound through the mutable mechanism + + env_lhs = setZonkType env_rhs (zonkTypeCollecting unbound_tv_set) + -- We need to gather the type variables mentioned on the LHS so we can + -- quantify over them. Example: + -- data T a = C + -- + -- foo :: T a -> Int + -- foo C = 1 + -- + -- {-# RULES "myrule" foo C = 1 #-} + -- + -- After type checking the LHS becomes (foo a (C a)) + -- and we do not want to zap the unbound tyvar 'a' to (), because + -- that limits the applicability of the rule. Instead, we + -- want to quantify over it! + -- + -- It's easiest to find the free tyvars here. Attempts to do so earlier + -- are tiresome, because (a) the data type is big and (b) finding the + -- free type vars of an expression is necessarily monadic operation. + -- (consider /\a -> f @ b, where b is side-effected to a) + in + zonkLExpr env_lhs lhs `thenM` \ new_lhs -> + zonkLExpr env_rhs rhs `thenM` \ new_rhs -> + + readMutVar unbound_tv_set `thenM` \ unbound_tvs -> + let + final_bndrs :: [Located Var] + final_bndrs = map noLoc (varSetElems unbound_tvs) ++ new_bndrs + in + returnM (HsRule name act (map RuleBndr final_bndrs) new_lhs fv_lhs new_rhs fv_rhs) + -- I hate this map RuleBndr stuff + where + zonk_bndr (RuleBndr v) + | isId (unLoc v) = wrapLocM (zonkIdBndr env) v + | otherwise = ASSERT( isImmutableTyVar (unLoc v) ) + return v +\end{code} + + +%************************************************************************ +%* * +\subsection[BackSubst-Foreign]{Foreign exports} +%* * +%************************************************************************ + +\begin{code} +zonkTcTypeToType :: ZonkEnv -> TcType -> TcM Type +zonkTcTypeToType (ZonkEnv zonk_ty _) ty = zonk_ty ty + +zonkTcTypeToTypes :: ZonkEnv -> [TcType] -> TcM [Type] +zonkTcTypeToTypes env tys = mapM (zonkTcTypeToType env) tys + +zonkTypeCollecting :: TcRef TyVarSet -> TcType -> TcM Type +-- This variant collects unbound type variables in a mutable variable +zonkTypeCollecting unbound_tv_set + = zonkType zonk_unbound_tyvar + where + zonk_unbound_tyvar tv + = zonkQuantifiedTyVar tv `thenM` \ tv' -> + readMutVar unbound_tv_set `thenM` \ tv_set -> + writeMutVar unbound_tv_set (extendVarSet tv_set tv') `thenM_` + return (mkTyVarTy tv') + +zonkTypeZapping :: TcType -> TcM Type +-- This variant is used for everything except the LHS of rules +-- It zaps unbound type variables to (), or some other arbitrary type +zonkTypeZapping ty + = zonkType zonk_unbound_tyvar ty + where + -- Zonk a mutable but unbound type variable to an arbitrary type + -- We know it's unbound even though we don't carry an environment, + -- because at the binding site for a type variable we bind the + -- mutable tyvar to a fresh immutable one. So the mutable store + -- plays the role of an environment. If we come across a mutable + -- type variable that isn't so bound, it must be completely free. + zonk_unbound_tyvar tv = do { writeMetaTyVar tv ty; return ty } + where + ty = mkArbitraryType tv + + +-- When the type checker finds a type variable with no binding, +-- which means it can be instantiated with an arbitrary type, it +-- usually instantiates it to Void. Eg. +-- +-- length [] +-- ===> +-- length Void (Nil Void) +-- +-- But in really obscure programs, the type variable might have +-- a kind other than *, so we need to invent a suitably-kinded type. +-- +-- This commit uses +-- Void for kind * +-- List for kind *->* +-- Tuple for kind *->...*->* +-- +-- which deals with most cases. (Previously, it only dealt with +-- kind *.) +-- +-- In the other cases, it just makes up a TyCon with a suitable +-- kind. If this gets into an interface file, anyone reading that +-- file won't understand it. This is fixable (by making the client +-- of the interface file make up a TyCon too) but it is tiresome and +-- never happens, so I am leaving it + +mkArbitraryType :: TcTyVar -> Type +-- Make up an arbitrary type whose kind is the same as the tyvar. +-- We'll use this to instantiate the (unbound) tyvar. +mkArbitraryType tv + | liftedTypeKind `isSubKind` kind = voidTy -- The vastly common case + | otherwise = mkTyConApp tycon [] + where + kind = tyVarKind tv + (args,res) = splitKindFunTys kind + + tycon | kind == tyConKind listTyCon -- *->* + = listTyCon -- No tuples this size + + | all isLiftedTypeKind args && isLiftedTypeKind res + = tupleTyCon Boxed (length args) -- *-> ... ->*->* + + | otherwise + = pprTrace "Urk! Inventing strangely-kinded void TyCon:" (ppr tc_name $$ ppr kind) $ + mkPrimTyCon tc_name kind 0 [] VoidRep + -- Same name as the tyvar, apart from making it start with a colon (sigh) + -- I dread to think what will happen if this gets out into an + -- interface file. Catastrophe likely. Major sigh. + + tc_name = mkInternalName (getUnique tv) (mkDerivedTyConOcc (getOccName tv)) noSrcLoc +\end{code} |