X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FcoreSyn%2FCoreLint.lhs;h=a3ba3ae250afa9d3a7bc2ab58116b3609e5a10ae;hp=dda8290bf4c62702f009a1511ba40290edc46a22;hb=f96194794bf099020706c3816d1a5678b40addbb;hpb=0065d5ab628975892cea1ec7303f968c3338cbe1 diff --git a/compiler/coreSyn/CoreLint.lhs b/compiler/coreSyn/CoreLint.lhs index dda8290..a3ba3ae 100644 --- a/compiler/coreSyn/CoreLint.lhs +++ b/compiler/coreSyn/CoreLint.lhs @@ -1,53 +1,48 @@ + % +% (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1993-1998 % -\section[CoreLint]{A ``lint'' pass to check for Core correctness} + +A ``lint'' pass to check for Core correctness \begin{code} module CoreLint ( lintCoreBindings, lintUnfolding, - showPass, endPass + showPass, endPass, endPassIf, endIteration ) where #include "HsVersions.h" +import NewDemand import CoreSyn -import CoreFVs ( idFreeVars ) -import CoreUtils ( findDefault, exprOkForSpeculation, coreBindsSize ) -import Unify ( coreRefineTys ) +import CoreFVs +import CoreUtils import Bag -import Literal ( literalType ) -import DataCon ( dataConRepType, isVanillaDataCon, dataConTyCon, dataConWorkId ) -import TysWiredIn ( tupleCon ) -import Var ( Var, Id, TyVar, idType, tyVarKind, mustHaveLocalBinding ) +import Literal +import DataCon +import TysWiredIn +import Var +import VarEnv import VarSet -import Name ( getSrcLoc ) +import Name +import Id +import IdInfo import PprCore -import ErrUtils ( dumpIfSet_core, ghcExit, Message, showPass, - mkLocMessage, debugTraceMsg ) -import SrcLoc ( SrcLoc, noSrcLoc, mkSrcSpan ) -import Type ( Type, tyVarsOfType, coreEqType, - splitFunTy_maybe, mkTyVarTys, - splitForAllTy_maybe, splitTyConApp_maybe, - isUnLiftedType, typeKind, mkForAllTy, mkFunTy, - isUnboxedTupleType, isSubKind, - substTyWith, emptyTvSubst, extendTvInScope, - TvSubst, TvSubstEnv, mkTvSubst, setTvSubstEnv, substTy, - extendTvSubst, composeTvSubst, isInScope, - getTvSubstEnv, getTvInScope ) -import TyCon ( isPrimTyCon ) -import BasicTypes ( RecFlag(..), Boxity(..), isNonRec ) -import StaticFlags ( opt_PprStyle_Debug ) -import DynFlags ( DynFlags, DynFlag(..), dopt ) +import ErrUtils +import SrcLoc +import Type +import Coercion +import TyCon +import BasicTypes +import StaticFlags +import ListSetOps +import DynFlags import Outputable - -#ifdef DEBUG -import Util ( notNull ) -#endif - -import Maybe - +import FastString +import Util +import Data.Maybe \end{code} %************************************************************************ @@ -61,8 +56,18 @@ place for them. They print out stuff before and after core passes, and do Core Lint when necessary. \begin{code} -endPass :: DynFlags -> String -> DynFlag -> [CoreBind] -> IO [CoreBind] -endPass dflags pass_name dump_flag binds +endPass :: DynFlags -> String -> DynFlag -> [CoreBind] -> IO () +endPass = dumpAndLint dumpIfSet_core + +endPassIf :: Bool -> DynFlags -> String -> DynFlag -> [CoreBind] -> IO () +endPassIf cond = dumpAndLint (dumpIf_core cond) + +endIteration :: DynFlags -> String -> DynFlag -> [CoreBind] -> IO () +endIteration = dumpAndLint dumpIfSet_dyn + +dumpAndLint :: (DynFlags -> DynFlag -> String -> SDoc -> IO ()) + -> DynFlags -> String -> DynFlag -> [CoreBind] -> IO () +dumpAndLint dump dflags pass_name dump_flag binds = do -- Report result size if required -- This has the side effect of forcing the intermediate to be evaluated @@ -70,12 +75,10 @@ endPass dflags pass_name dump_flag binds (text " Result size =" <+> int (coreBindsSize binds)) -- Report verbosely, if required - dumpIfSet_core dflags dump_flag pass_name (pprCoreBindings binds) + dump dflags dump_flag pass_name (pprCoreBindings binds) -- Type check lintCoreBindings dflags pass_name binds - - return binds \end{code} @@ -109,10 +112,31 @@ Outstanding issues: -- * Oversaturated type app after specialisation (eta reduction -- may well be happening...); + +Note [Linting type lets] +~~~~~~~~~~~~~~~~~~~~~~~~ +In the desugarer, it's very very convenient to be able to say (in effect) + let a = Type Int in +That is, use a type let. See Note [Type let] in CoreSyn. + +However, when linting we need to remember that a=Int, else we might +reject a correct program. So we carry a type substitution (in this example +[a -> Int]) and apply this substitution before comparing types. The functin + lintTy :: Type -> LintM Type +returns a substituted type; that's the only reason it returns anything. + +When we encounter a binder (like x::a) we must apply the substitution +to the type of the binding variable. lintBinders does this. + +For Ids, the type-substituted Id is added to the in_scope set (which +itself is part of the TvSubst we are carrying down), and when we +find an occurence of an Id, we fetch it from the in-scope set. + + \begin{code} lintCoreBindings :: DynFlags -> String -> [CoreBind] -> IO () -lintCoreBindings dflags whoDunnit binds +lintCoreBindings dflags _whoDunnit _binds | not (dopt Opt_DoCoreLinting dflags) = return () @@ -125,18 +149,19 @@ lintCoreBindings dflags whoDunnit binds -- Put all the top-level binders in scope at the start -- This is because transformation rules can bring something -- into use 'unexpectedly' - lint_binds binds = addInScopeVars (bindersOfBinds binds) $ + lint_binds binds = addLoc TopLevelBindings $ + addInScopeVars (bindersOfBinds binds) $ mapM lint_bind binds - lint_bind (Rec prs) = mapM_ (lintSingleBinding Recursive) prs - lint_bind (NonRec bndr rhs) = lintSingleBinding NonRecursive (bndr,rhs) + lint_bind (Rec prs) = mapM_ (lintSingleBinding TopLevel Recursive) prs + lint_bind (NonRec bndr rhs) = lintSingleBinding TopLevel NonRecursive (bndr,rhs) display bad_news = vcat [ text ("*** Core Lint Errors: in result of " ++ whoDunnit ++ " ***"), bad_news, - ptext SLIT("*** Offending Program ***"), + ptext (sLit "*** Offending Program ***"), pprCoreBindings binds, - ptext SLIT("*** End of Offense ***") + ptext (sLit "*** End of Offense ***") ] \end{code} @@ -170,7 +195,8 @@ lintUnfolding locn vars expr Check a core binding, returning the list of variables bound. \begin{code} -lintSingleBinding rec_flag (binder,rhs) +lintSingleBinding :: TopLevelFlag -> RecFlag -> (Id, CoreExpr) -> LintM () +lintSingleBinding top_lvl_flag rec_flag (binder,rhs) = addLoc (RhsOf binder) $ -- Check the rhs do { ty <- lintCoreExpr rhs @@ -181,14 +207,31 @@ lintSingleBinding rec_flag (binder,rhs) ; checkL (not (isUnLiftedType binder_ty) || (isNonRec rec_flag && exprOkForSpeculation rhs)) (mkRhsPrimMsg binder rhs) + -- Check that if the binder is top-level or recursive, it's not demanded + ; checkL (not (isStrictId binder) + || (isNonRec rec_flag && not (isTopLevel top_lvl_flag))) + (mkStrictMsg binder) -- Check whether binder's specialisations contain any out-of-scope variables - ; mapM_ (checkBndrIdInScope binder) bndr_vars } + ; mapM_ (checkBndrIdInScope binder) bndr_vars + + -- Check whether arity and demand type are consistent (only if demand analysis + -- already happened) + ; checkL (case maybeDmdTy of + Just (StrictSig dmd_ty) -> idArity binder >= dmdTypeDepth dmd_ty || exprIsTrivial rhs + Nothing -> True) + (mkArityMsg binder) } -- We should check the unfolding, if any, but this is tricky because - -- the unfolding is a SimplifiableCoreExpr. Give up for now. - where - binder_ty = idType binder - bndr_vars = varSetElems (idFreeVars binder) + -- the unfolding is a SimplifiableCoreExpr. Give up for now. + where + binder_ty = idType binder + maybeDmdTy = idNewStrictness_maybe binder + bndr_vars = varSetElems (idFreeVars binder `unionVarSet` wkr_vars) + wkr_vars | workerExists wkr_info = unitVarSet (workerId wkr_info) + | otherwise = emptyVarSet + wkr_info = idWorkerInfo binder + lintBinder var | isId var = lintIdBndr var $ \_ -> (return ()) + | otherwise = return () \end{code} %************************************************************************ @@ -205,79 +248,64 @@ lintCoreExpr :: CoreExpr -> LintM OutType -- The returned type has the substitution from the monad -- already applied to it: -- lintCoreExpr e subst = exprType (subst e) +-- +-- The returned "type" can be a kind, if the expression is (Type ty) lintCoreExpr (Var var) - = do { checkIdInScope var - ; applySubst (idType var) } + = do { checkL (not (var == oneTupleDataConId)) + (ptext (sLit "Illegal one-tuple")) + + ; checkDeadIdOcc var + ; var' <- lookupIdInScope var + ; return (idType var') + } lintCoreExpr (Lit lit) = return (literalType lit) -lintCoreExpr (Note (Coerce to_ty from_ty) expr) - = do { expr_ty <- lintCoreExpr expr - ; to_ty <- lintTy to_ty - ; from_ty <- lintTy from_ty - ; checkTys from_ty expr_ty (mkCoerceErr from_ty expr_ty) - ; return to_ty } - -lintCoreExpr (Note other_note expr) +--lintCoreExpr (Note (Coerce to_ty from_ty) expr) +-- = do { expr_ty <- lintCoreExpr expr +-- ; to_ty <- lintTy to_ty +-- ; from_ty <- lintTy from_ty +-- ; checkTys from_ty expr_ty (mkCoerceErr from_ty expr_ty) +-- ; return to_ty } + +lintCoreExpr (Cast expr co) + = do { expr_ty <- lintCoreExpr expr + ; co' <- lintTy co + ; let (from_ty, to_ty) = coercionKind co' + ; checkTys from_ty expr_ty (mkCastErr from_ty expr_ty) + ; return to_ty } + +lintCoreExpr (Note _ expr) = lintCoreExpr expr +lintCoreExpr (Let (NonRec tv (Type ty)) body) + = -- See Note [Type let] in CoreSyn + do { checkL (isTyVar tv) (mkKindErrMsg tv ty) -- Not quite accurate + ; ty' <- lintTy ty + ; kind' <- lintTy (tyVarKind tv) + ; let tv' = setTyVarKind tv kind' + ; checkKinds tv' ty' + -- Now extend the substitution so we + -- take advantage of it in the body + ; addLoc (BodyOfLetRec [tv]) $ + addInScopeVars [tv'] $ + extendSubstL tv' ty' $ + lintCoreExpr body } + lintCoreExpr (Let (NonRec bndr rhs) body) - = do { lintSingleBinding NonRecursive (bndr,rhs) + = do { lintSingleBinding NotTopLevel NonRecursive (bndr,rhs) ; addLoc (BodyOfLetRec [bndr]) - (addInScopeVars [bndr] (lintCoreExpr body)) } + (lintAndScopeId bndr $ \_ -> (lintCoreExpr body)) } lintCoreExpr (Let (Rec pairs) body) - = addInScopeVars bndrs $ - do { mapM (lintSingleBinding Recursive) pairs + = lintAndScopeIds bndrs $ \_ -> + do { mapM_ (lintSingleBinding NotTopLevel Recursive) pairs ; addLoc (BodyOfLetRec bndrs) (lintCoreExpr body) } where bndrs = map fst pairs -lintCoreExpr e@(App fun (Type ty)) --- This is like 'let' for types --- It's needed when dealing with desugarer output for GADTs. Consider --- data T = forall a. T a (a->Int) Bool --- f :: T -> ... -> --- f (T x f True) = --- f (T y g False) = --- After desugaring we get --- f t b = case t of --- T a (x::a) (f::a->Int) (b:Bool) -> --- case b of --- True -> --- False -> (/\b. let y=x; g=f in ) a --- And for a reason I now forget, the ...... can mention a; so --- we want Lint to know that b=a. Ugh. --- --- I tried quite hard to make the necessity for this go away, by changing the --- desugarer, but the fundamental problem is this: --- --- T a (x::a) (y::Int) -> let fail::a = ... --- in (/\b. ...(case ... of --- True -> x::b --- False -> fail) --- ) a --- Now the inner case look as though it has incompatible branches. - = addLoc (AnExpr e) $ - go fun [ty] - where - go (App fun (Type ty)) tys - = do { go fun (ty:tys) } - go (Lam tv body) (ty:tys) - = do { checkL (isTyVar tv) (mkKindErrMsg tv ty) -- Not quite accurate - ; ty' <- lintTy ty; - ; checkKinds tv ty' - -- Now extend the substitution so we - -- take advantage of it in the body - ; addInScopeVars [tv] $ - extendSubstL tv ty' $ - go body tys } - go fun tys - = do { fun_ty <- lintCoreExpr fun - ; lintCoreArgs fun_ty (map Type tys) } - lintCoreExpr e@(App fun arg) = do { fun_ty <- lintCoreExpr fun ; addLoc (AnExpr e) $ @@ -285,14 +313,13 @@ lintCoreExpr e@(App fun arg) lintCoreExpr (Lam var expr) = addLoc (LambdaBodyOf var) $ - do { body_ty <- addInScopeVars [var] $ - lintCoreExpr expr - ; if isId var then do - { var_ty <- lintId var - ; return (mkFunTy var_ty body_ty) } - else - return (mkForAllTy var body_ty) - } + lintBinders [var] $ \[var'] -> + do { body_ty <- lintCoreExpr expr + ; if isId var' then + return (mkFunTy (idType var') body_ty) + else + return (mkForAllTy var' body_ty) + } -- The applySubst is needed to apply the subst to var lintCoreExpr e@(Case scrut var alt_ty alts) = @@ -300,20 +327,39 @@ lintCoreExpr e@(Case scrut var alt_ty alts) = do { scrut_ty <- lintCoreExpr scrut ; alt_ty <- lintTy alt_ty ; var_ty <- lintTy (idType var) - -- Don't use lintId on var, because unboxed tuple is legitimate - ; checkTys var_ty scrut_ty (mkScrutMsg var scrut_ty) + ; let mb_tc_app = splitTyConApp_maybe (idType var) + ; case mb_tc_app of + Just (tycon, _) + | debugIsOn && + isAlgTyCon tycon && + not (isOpenTyCon tycon) && + null (tyConDataCons tycon) -> + pprTrace "Lint warning: case binder's type has no constructors" (ppr var <+> ppr (idType var)) + -- This can legitimately happen for type families + $ return () + _otherwise -> return () + + -- Don't use lintIdBndr on var, because unboxed tuple is legitimate + + ; subst <- getTvSubst + ; checkTys var_ty scrut_ty (mkScrutMsg var var_ty scrut_ty subst) -- If the binder is an unboxed tuple type, don't put it in scope - ; let vars = if (isUnboxedTupleType (idType var)) then [] else [var] - ; addInScopeVars vars $ + ; let scope = if (isUnboxedTupleType (idType var)) then + pass_var + else lintAndScopeId var + ; scope $ \_ -> do { -- Check the alternatives - checkCaseAlts e scrut_ty alts - ; mapM (lintCoreAlt scrut_ty alt_ty) alts + mapM_ (lintCoreAlt scrut_ty alt_ty) alts + ; checkCaseAlts e scrut_ty alts ; return alt_ty } } + where + pass_var f = f var -lintCoreExpr e@(Type ty) - = addErrL (mkStrangeTyMsg e) +lintCoreExpr (Type ty) + = do { ty' <- lintTy ty + ; return (typeKind ty') } \end{code} %************************************************************************ @@ -326,8 +372,8 @@ The basic version of these functions checks that the argument is a subtype of the required type, as one would expect. \begin{code} -lintCoreArgs :: Type -> [CoreArg] -> LintM Type -lintCoreArg :: Type -> CoreArg -> LintM Type +lintCoreArgs :: OutType -> [CoreArg] -> LintM OutType +lintCoreArg :: OutType -> CoreArg -> LintM OutType -- First argument has already had substitution applied to it \end{code} @@ -337,23 +383,25 @@ lintCoreArgs ty (a : args) = do { res <- lintCoreArg ty a ; lintCoreArgs res args } -lintCoreArg fun_ty a@(Type arg_ty) = +lintCoreArg fun_ty (Type arg_ty) = do { arg_ty <- lintTy arg_ty ; lintTyApp fun_ty arg_ty } lintCoreArg fun_ty arg = -- Make sure function type matches argument do { arg_ty <- lintCoreExpr arg - ; let err = mkAppMsg fun_ty arg_ty arg + ; let err1 = mkAppMsg fun_ty arg_ty arg + err2 = mkNonFunAppMsg fun_ty arg_ty arg ; case splitFunTy_maybe fun_ty of Just (arg,res) -> - do { checkTys arg arg_ty err + do { checkTys arg arg_ty err1 ; return res } - _ -> addErrL err } + _ -> addErrL err2 } \end{code} \begin{code} -- Both args have had substitution applied +lintTyApp :: OutType -> OutType -> LintM OutType lintTyApp ty arg_ty = case splitForAllTy_maybe ty of Nothing -> addErrL (mkTyAppMsg ty arg_ty) @@ -363,22 +411,29 @@ lintTyApp ty arg_ty ; checkKinds tyvar arg_ty ; return (substTyWith [tyvar] [arg_ty] body) } -lintTyApps fun_ty [] = return fun_ty - -lintTyApps fun_ty (arg_ty : arg_tys) = - do { fun_ty' <- lintTyApp fun_ty arg_ty - ; lintTyApps fun_ty' arg_tys } - +checkKinds :: Var -> Type -> LintM () checkKinds tyvar arg_ty -- Arg type might be boxed for a function with an uncommitted -- tyvar; notably this is used so that we can give -- error :: forall a:*. String -> a -- and then apply it to both boxed and unboxed types. - = checkL (argty_kind `isSubKind` tyvar_kind) + = checkL (arg_kind `isSubKind` tyvar_kind) (mkKindErrMsg tyvar arg_ty) where tyvar_kind = tyVarKind tyvar - argty_kind = typeKind arg_ty + arg_kind | isCoVar tyvar = coercionKindPredTy arg_ty + | otherwise = typeKind arg_ty + +checkDeadIdOcc :: Id -> LintM () +-- Occurrences of an Id should never be dead.... +-- except when we are checking a case pattern +checkDeadIdOcc id + | isDeadOcc (idOccInfo id) + = do { in_case <- inCasePat + ; checkL in_case + (ptext (sLit "Occurrence of a dead Id") <+> ppr id) } + | otherwise + = return () \end{code} @@ -398,7 +453,7 @@ checkCaseAlts :: CoreExpr -> OutType -> [CoreAlt] -> LintM () -- the simplifer correctly eliminates case that can't -- possibly match. -checkCaseAlts e ty [] +checkCaseAlts e _ [] = addErrL (mkNullAltsMsg e) checkCaseAlts e ty alts = @@ -411,14 +466,14 @@ checkCaseAlts e ty alts = -- Check that successive alternatives have increasing tags increasing_tag (alt1 : rest@( alt2 : _)) = alt1 `ltAlt` alt2 && increasing_tag rest - increasing_tag other = True + increasing_tag _ = True non_deflt (DEFAULT, _, _) = False - non_deflt alt = True + non_deflt _ = True is_infinite_ty = case splitTyConApp_maybe ty of - Nothing -> False - Just (tycon, tycon_arg_tys) -> isPrimTyCon tycon + Nothing -> False + Just (tycon, _) -> isPrimTyCon tycon \end{code} \begin{code} @@ -432,11 +487,11 @@ lintCoreAlt :: OutType -- Type of scrutinee -> CoreAlt -> LintM () -lintCoreAlt scrut_ty alt_ty alt@(DEFAULT, args, rhs) = +lintCoreAlt _ alt_ty (DEFAULT, args, rhs) = do { checkL (null args) (mkDefaultArgsMsg args) ; checkAltExpr rhs alt_ty } -lintCoreAlt scrut_ty alt_ty alt@(LitAlt lit, args, rhs) = +lintCoreAlt scrut_ty alt_ty (LitAlt lit, args, rhs) = do { checkL (null args) (mkDefaultArgsMsg args) ; checkTys lit_ty scrut_ty (mkBadPatMsg lit_ty scrut_ty) ; checkAltExpr rhs alt_ty } @@ -444,50 +499,30 @@ lintCoreAlt scrut_ty alt_ty alt@(LitAlt lit, args, rhs) = lit_ty = literalType lit lintCoreAlt scrut_ty alt_ty alt@(DataAlt con, args, rhs) - | Just (tycon, tycon_arg_tys) <- splitTyConApp_maybe scrut_ty, - tycon == dataConTyCon con - = addLoc (CaseAlt alt) $ - addInScopeVars args $ -- Put the args in scope before lintBinder, - -- because the Ids mention the type variables - if isVanillaDataCon con then - do { addLoc (CasePat alt) $ do - { mapM lintBinder args - -- FIX! Add check that all args are Ids. - -- Check the pattern + | isNewTyCon (dataConTyCon con) = addErrL (mkNewTyDataConAltMsg scrut_ty alt) + | Just (tycon, tycon_arg_tys) <- splitTyConApp_maybe scrut_ty + = addLoc (CaseAlt alt) $ do + { -- First instantiate the universally quantified + -- type variables of the data constructor + -- We've already check + checkL (tycon == dataConTyCon con) (mkBadConMsg tycon con) + ; let con_payload_ty = applyTys (dataConRepType con) tycon_arg_tys + + -- And now bring the new binders into scope + ; lintBinders args $ \ args -> do + { addLoc (CasePat alt) $ do + { -- Check the pattern -- Scrutinee type must be a tycon applicn; checked by caller -- This code is remarkably compact considering what it does! - -- NB: args must be in scope here so that the lintCoreArgs line works. - -- NB: relies on existential type args coming *after* ordinary type args - - ; con_type <- lintTyApps (dataConRepType con) tycon_arg_tys - -- Can just map Var as we know that this is a vanilla datacon - ; con_result_ty <- lintCoreArgs con_type (map Var args) + -- NB: args must be in scope here so that the lintCoreArgs + -- line works. + -- NB: relies on existential type args coming *after* + -- ordinary type args + ; con_result_ty <- lintCoreArgs con_payload_ty (varsToCoreExprs args) ; checkTys con_result_ty scrut_ty (mkBadPatMsg con_result_ty scrut_ty) } -- Check the RHS - ; checkAltExpr rhs alt_ty } - - else -- GADT - do { let (tvs,ids) = span isTyVar args - ; subst <- getTvSubst - ; let in_scope = getTvInScope subst - subst_env = getTvSubstEnv subst - ; case coreRefineTys con tvs scrut_ty of { - Nothing -> return () ; -- Alternative is dead code - Just (refine, _) -> updateTvSubstEnv (composeTvSubst in_scope refine subst_env) $ - do { addLoc (CasePat alt) $ do - { tvs' <- mapM lintTy (mkTyVarTys tvs) - ; con_type <- lintTyApps (dataConRepType con) tvs' - ; mapM lintBinder ids -- Lint Ids in the refined world - ; lintCoreArgs con_type (map Var ids) - } - - ; let refined_alt_ty = substTy (mkTvSubst in_scope refine) alt_ty - -- alt_ty is already an OutType, so don't re-apply - -- the current substitution. But we must apply the - -- refinement so that the check in checkAltExpr is ok - ; checkAltExpr rhs refined_alt_ty - } } } + ; checkAltExpr rhs alt_ty } } | otherwise -- Scrut-ty is wrong shape = addErrL (mkBadAltMsg scrut_ty alt) @@ -500,24 +535,60 @@ lintCoreAlt scrut_ty alt_ty alt@(DataAlt con, args, rhs) %************************************************************************ \begin{code} -lintBinder :: Var -> LintM () -lintBinder var | isId var = lintId var >> return () - | otherwise = return () - -lintId :: Var -> LintM OutType +-- When we lint binders, we (one at a time and in order): +-- 1. Lint var types or kinds (possibly substituting) +-- 2. Add the binder to the in scope set, and if its a coercion var, +-- we may extend the substitution to reflect its (possibly) new kind +lintBinders :: [Var] -> ([Var] -> LintM a) -> LintM a +lintBinders [] linterF = linterF [] +lintBinders (var:vars) linterF = lintBinder var $ \var' -> + lintBinders vars $ \ vars' -> + linterF (var':vars') + +lintBinder :: Var -> (Var -> LintM a) -> LintM a +lintBinder var linterF + | isTyVar var = lint_ty_bndr + | otherwise = lintIdBndr var linterF + where + lint_ty_bndr = do { _ <- lintTy (tyVarKind var) + ; subst <- getTvSubst + ; let (subst', tv') = substTyVarBndr subst var + ; updateTvSubst subst' (linterF tv') } + +lintIdBndr :: Var -> (Var -> LintM a) -> LintM a +-- Do substitution on the type of a binder and add the var with this +-- new type to the in-scope set of the second argument -- ToDo: lint its rules -lintId id +lintIdBndr id linterF = do { checkL (not (isUnboxedTupleType (idType id))) (mkUnboxedTupleMsg id) -- No variable can be bound to an unboxed tuple. - ; lintTy (idType id) } + ; lintAndScopeId id $ \id' -> linterF id' + } + +lintAndScopeIds :: [Var] -> ([Var] -> LintM a) -> LintM a +lintAndScopeIds ids linterF + = go ids + where + go [] = linterF [] + go (id:ids) = do { lintAndScopeId id $ \id -> + lintAndScopeIds ids $ \ids -> + linterF (id:ids) } + +lintAndScopeId :: Var -> (Var -> LintM a) -> LintM a +lintAndScopeId id linterF + = do { ty <- lintTy (idType id) + ; let id' = setIdType id ty + ; addInScopeVars [id'] $ (linterF id') + } lintTy :: InType -> LintM OutType -- Check the type, and apply the substitution to it +-- See Note [Linting type lets] -- ToDo: check the kind structure of the type lintTy ty = do { ty' <- applySubst ty - ; mapM_ checkIdInScope (varSetElems (tyVarsOfType ty')) + ; mapM_ checkTyVarInScope (varSetElems (tyVarsOfType ty')) ; return ty' } \end{code} @@ -538,8 +609,23 @@ newtype LintM a = Bag Message -> -- Error messages so far (Maybe a, Bag Message) } -- Result and error messages (if any) +{- Note [Type substitution] + ~~~~~~~~~~~~~~~~~~~~~~~~ +Why do we need a type substitution? Consider + /\(a:*). \(x:a). /\(a:*). id a x +This is ill typed, because (renaming variables) it is really + /\(a:*). \(x:a). /\(b:*). id b x +Hence, when checking an application, we can't naively compare x's type +(at its binding site) with its expected type (at a use site). So we +rename type binders as we go, maintaining a substitution. + +The same substitution also supports let-type, current expressed as + (/\(a:*). body) ty +Here we substitute 'ty' for 'a' in 'body', on the fly. +-} + instance Monad LintM where - return x = LintM (\ loc subst errs -> (Just x, errs)) + return x = LintM (\ _ _ errs -> (Just x, errs)) fail err = LintM (\ loc subst errs -> (Nothing, addErr subst errs (text err) loc)) m >>= k = LintM (\ loc subst errs -> let (res, errs') = unLintM m loc subst errs in @@ -552,9 +638,10 @@ data LintLocInfo | LambdaBodyOf Id -- The lambda-binder | BodyOfLetRec [Id] -- One of the binders | CaseAlt CoreAlt -- Case alternative - | CasePat CoreAlt -- *Pattern* of the case alternative + | CasePat CoreAlt -- The *pattern* of the case alternative | AnExpr CoreExpr -- Some expression | ImportedUnfolding SrcLoc -- Some imported unfolding (ToDo: say which) + | TopLevelBindings \end{code} @@ -563,12 +650,12 @@ initL :: LintM a -> Maybe Message {- errors -} initL m = case unLintM m [] emptyTvSubst emptyBag of (_, errs) | isEmptyBag errs -> Nothing - | otherwise -> Just (vcat (punctuate (text "") (bagToList errs))) + | otherwise -> Just (vcat (punctuate blankLine (bagToList errs))) \end{code} \begin{code} checkL :: Bool -> Message -> LintM () -checkL True msg = return () +checkL True _ = return () checkL False msg = addErrL msg addErrL :: Message -> LintM a @@ -582,7 +669,7 @@ addErr subst errs_so_far msg locs (loc, cxt1) = dumpLoc (head locs) cxts = [snd (dumpLoc loc) | loc <- locs] context | opt_PprStyle_Debug = vcat (reverse cxts) $$ cxt1 $$ - ptext SLIT("Substitution:") <+> ppr subst + ptext (sLit "Substitution:") <+> ppr subst | otherwise = cxt1 mk_msg msg = mkLocMessage (mkSrcSpan loc loc) (context $$ msg) @@ -591,16 +678,27 @@ addLoc :: LintLocInfo -> LintM a -> LintM a addLoc extra_loc m = LintM (\ loc subst errs -> unLintM m (extra_loc:loc) subst errs) +inCasePat :: LintM Bool -- A slight hack; see the unique call site +inCasePat = LintM $ \ loc _ errs -> (Just (is_case_pat loc), errs) + where + is_case_pat (CasePat {} : _) = True + is_case_pat _other = False + addInScopeVars :: [Var] -> LintM a -> LintM a -addInScopeVars vars m = - LintM (\ loc subst errs -> unLintM m loc (extendTvInScope subst vars) errs) +addInScopeVars vars m + | null dups + = LintM (\ loc subst errs -> unLintM m loc (extendTvInScope subst vars) errs) + | otherwise + = addErrL (dupVars dups) + where + (_, dups) = removeDups compare vars -updateTvSubstEnv :: TvSubstEnv -> LintM a -> LintM a -updateTvSubstEnv substenv m = - LintM (\ loc subst errs -> unLintM m loc (setTvSubstEnv subst substenv) errs) +updateTvSubst :: TvSubst -> LintM a -> LintM a +updateTvSubst subst' m = + LintM (\ loc _ errs -> unLintM m loc subst' errs) getTvSubst :: LintM TvSubst -getTvSubst = LintM (\ loc subst errs -> (Just subst, errs)) +getTvSubst = LintM (\ _ subst errs -> (Just subst, errs)) applySubst :: Type -> LintM Type applySubst ty = do { subst <- getTvSubst; return (substTy subst ty) } @@ -611,11 +709,19 @@ extendSubstL tv ty m \end{code} \begin{code} -checkIdInScope :: Var -> LintM () -checkIdInScope id - = do { checkL (not (id == oneTupleDataConId)) - (ptext SLIT("Illegal one-tuple")) - ; checkInScope (ptext SLIT("is out of scope")) id } +lookupIdInScope :: Id -> LintM Id +lookupIdInScope id + | not (mustHaveLocalBinding id) + = return id -- An imported Id + | otherwise + = do { subst <- getTvSubst + ; case lookupInScope (getTvInScope subst) id of + Just v -> return v + Nothing -> do { _ <- addErrL out_of_scope + ; return id } } + where + out_of_scope = ppr id <+> ptext (sLit "is out of scope") + oneTupleDataConId :: Id -- Should not happen oneTupleDataConId = dataConWorkId (tupleCon Boxed 1) @@ -624,9 +730,12 @@ checkBndrIdInScope :: Var -> Var -> LintM () checkBndrIdInScope binder id = checkInScope msg id where - msg = ptext SLIT("is out of scope inside info for") <+> + msg = ptext (sLit "is out of scope inside info for") <+> ppr binder +checkTyVarInScope :: TyVar -> LintM () +checkTyVarInScope tv = checkInScope (ptext (sLit "is out of scope")) tv + checkInScope :: SDoc -> Var -> LintM () checkInScope loc_msg var = do { subst <- getTvSubst @@ -647,36 +756,40 @@ checkTys ty1 ty2 msg = checkL (ty1 `coreEqType` ty2) msg %************************************************************************ \begin{code} +dumpLoc :: LintLocInfo -> (SrcLoc, SDoc) + dumpLoc (RhsOf v) - = (getSrcLoc v, brackets (ptext SLIT("RHS of") <+> pp_binders [v])) + = (getSrcLoc v, brackets (ptext (sLit "RHS of") <+> pp_binders [v])) dumpLoc (LambdaBodyOf b) - = (getSrcLoc b, brackets (ptext SLIT("in body of lambda with binder") <+> pp_binder b)) + = (getSrcLoc b, brackets (ptext (sLit "in body of lambda with binder") <+> pp_binder b)) dumpLoc (BodyOfLetRec []) - = (noSrcLoc, brackets (ptext SLIT("In body of a letrec with no binders"))) + = (noSrcLoc, brackets (ptext (sLit "In body of a letrec with no binders"))) dumpLoc (BodyOfLetRec bs@(_:_)) - = ( getSrcLoc (head bs), brackets (ptext SLIT("in body of letrec with binders") <+> pp_binders bs)) + = ( getSrcLoc (head bs), brackets (ptext (sLit "in body of letrec with binders") <+> pp_binders bs)) dumpLoc (AnExpr e) = (noSrcLoc, text "In the expression:" <+> ppr e) -dumpLoc (CaseAlt (con, args, rhs)) +dumpLoc (CaseAlt (con, args, _)) = (noSrcLoc, text "In a case alternative:" <+> parens (ppr con <+> pp_binders args)) -dumpLoc (CasePat (con, args, rhs)) +dumpLoc (CasePat (con, args, _)) = (noSrcLoc, text "In the pattern of a case alternative:" <+> parens (ppr con <+> pp_binders args)) dumpLoc (ImportedUnfolding locn) - = (locn, brackets (ptext SLIT("in an imported unfolding"))) + = (locn, brackets (ptext (sLit "in an imported unfolding"))) +dumpLoc TopLevelBindings + = (noSrcLoc, empty) pp_binders :: [Var] -> SDoc pp_binders bs = sep (punctuate comma (map pp_binder bs)) pp_binder :: Var -> SDoc pp_binder b | isId b = hsep [ppr b, dcolon, ppr (idType b)] - | isTyVar b = hsep [ppr b, dcolon, ppr (tyVarKind b)] + | otherwise = hsep [ppr b, dcolon, ppr (tyVarKind b)] \end{code} \begin{code} @@ -698,13 +811,14 @@ mkCaseAltMsg e ty1 ty2 = hang (text "Type of case alternatives not the same as the annotation on case:") 4 (vcat [ppr ty1, ppr ty2, ppr e]) -mkScrutMsg :: Id -> Type -> Message -mkScrutMsg var scrut_ty +mkScrutMsg :: Id -> Type -> Type -> TvSubst -> Message +mkScrutMsg var var_ty scrut_ty subst = vcat [text "Result binder in case doesn't match scrutinee:" <+> ppr var, - text "Result binder type:" <+> ppr (idType var), - text "Scrutinee type:" <+> ppr scrut_ty] - + text "Result binder type:" <+> ppr var_ty,--(idType var), + text "Scrutinee type:" <+> ppr scrut_ty, + hsep [ptext (sLit "Current TV subst"), ppr subst]] +mkNonDefltMsg, mkNonIncreasingAltsMsg :: CoreExpr -> Message mkNonDefltMsg e = hang (text "Case expression with DEFAULT not at the beginnning") 4 (ppr e) mkNonIncreasingAltsMsg e @@ -714,6 +828,14 @@ nonExhaustiveAltsMsg :: CoreExpr -> Message nonExhaustiveAltsMsg e = hang (text "Case expression with non-exhaustive alternatives") 4 (ppr e) +mkBadConMsg :: TyCon -> DataCon -> Message +mkBadConMsg tycon datacon + = vcat [ + text "In a case alternative, data constructor isn't in scrutinee type:", + text "Scrutinee type constructor:" <+> ppr tycon, + text "Data con:" <+> ppr datacon + ] + mkBadPatMsg :: Type -> Type -> Message mkBadPatMsg con_result_ty scrut_ty = vcat [ @@ -728,58 +850,95 @@ mkBadAltMsg scrut_ty alt text "Scrutinee type:" <+> ppr scrut_ty, text "Alternative:" <+> pprCoreAlt alt ] +mkNewTyDataConAltMsg :: Type -> CoreAlt -> Message +mkNewTyDataConAltMsg scrut_ty alt + = vcat [ text "Data alternative for newtype datacon", + text "Scrutinee type:" <+> ppr scrut_ty, + text "Alternative:" <+> pprCoreAlt alt ] + + ------------------------------------------------------ -- Other error messages mkAppMsg :: Type -> Type -> CoreExpr -> Message mkAppMsg fun_ty arg_ty arg - = vcat [ptext SLIT("Argument value doesn't match argument type:"), - hang (ptext SLIT("Fun type:")) 4 (ppr fun_ty), - hang (ptext SLIT("Arg type:")) 4 (ppr arg_ty), - hang (ptext SLIT("Arg:")) 4 (ppr arg)] + = vcat [ptext (sLit "Argument value doesn't match argument type:"), + hang (ptext (sLit "Fun type:")) 4 (ppr fun_ty), + hang (ptext (sLit "Arg type:")) 4 (ppr arg_ty), + hang (ptext (sLit "Arg:")) 4 (ppr arg)] + +mkNonFunAppMsg :: Type -> Type -> CoreExpr -> Message +mkNonFunAppMsg fun_ty arg_ty arg + = vcat [ptext (sLit "Non-function type in function position"), + hang (ptext (sLit "Fun type:")) 4 (ppr fun_ty), + hang (ptext (sLit "Arg type:")) 4 (ppr arg_ty), + hang (ptext (sLit "Arg:")) 4 (ppr arg)] mkKindErrMsg :: TyVar -> Type -> Message mkKindErrMsg tyvar arg_ty - = vcat [ptext SLIT("Kinds don't match in type application:"), - hang (ptext SLIT("Type variable:")) + = vcat [ptext (sLit "Kinds don't match in type application:"), + hang (ptext (sLit "Type variable:")) 4 (ppr tyvar <+> dcolon <+> ppr (tyVarKind tyvar)), - hang (ptext SLIT("Arg type:")) + hang (ptext (sLit "Arg type:")) 4 (ppr arg_ty <+> dcolon <+> ppr (typeKind arg_ty))] mkTyAppMsg :: Type -> Type -> Message mkTyAppMsg ty arg_ty = vcat [text "Illegal type application:", - hang (ptext SLIT("Exp type:")) + hang (ptext (sLit "Exp type:")) 4 (ppr ty <+> dcolon <+> ppr (typeKind ty)), - hang (ptext SLIT("Arg type:")) + hang (ptext (sLit "Arg type:")) 4 (ppr arg_ty <+> dcolon <+> ppr (typeKind arg_ty))] mkRhsMsg :: Id -> Type -> Message mkRhsMsg binder ty = vcat - [hsep [ptext SLIT("The type of this binder doesn't match the type of its RHS:"), + [hsep [ptext (sLit "The type of this binder doesn't match the type of its RHS:"), ppr binder], - hsep [ptext SLIT("Binder's type:"), ppr (idType binder)], - hsep [ptext SLIT("Rhs type:"), ppr ty]] + hsep [ptext (sLit "Binder's type:"), ppr (idType binder)], + hsep [ptext (sLit "Rhs type:"), ppr ty]] mkRhsPrimMsg :: Id -> CoreExpr -> Message -mkRhsPrimMsg binder rhs - = vcat [hsep [ptext SLIT("The type of this binder is primitive:"), +mkRhsPrimMsg binder _rhs + = vcat [hsep [ptext (sLit "The type of this binder is primitive:"), ppr binder], - hsep [ptext SLIT("Binder's type:"), ppr (idType binder)] + hsep [ptext (sLit "Binder's type:"), ppr (idType binder)] ] +mkStrictMsg :: Id -> Message +mkStrictMsg binder + = vcat [hsep [ptext (sLit "Recursive or top-level binder has strict demand info:"), + ppr binder], + hsep [ptext (sLit "Binder's demand info:"), ppr (idNewDemandInfo binder)] + ] + +mkArityMsg :: Id -> Message +mkArityMsg binder + = vcat [hsep [ptext (sLit "Demand type has "), + ppr (dmdTypeDepth dmd_ty), + ptext (sLit " arguments, rhs has "), + ppr (idArity binder), + ptext (sLit "arguments, "), + ppr binder], + hsep [ptext (sLit "Binder's strictness signature:"), ppr dmd_ty] + + ] + where (StrictSig dmd_ty) = idNewStrictness binder + mkUnboxedTupleMsg :: Id -> Message mkUnboxedTupleMsg binder - = vcat [hsep [ptext SLIT("A variable has unboxed tuple type:"), ppr binder], - hsep [ptext SLIT("Binder's type:"), ppr (idType binder)]] - -mkCoerceErr from_ty expr_ty - = vcat [ptext SLIT("From-type of Coerce differs from type of enclosed expression"), - ptext SLIT("From-type:") <+> ppr from_ty, - ptext SLIT("Type of enclosed expr:") <+> ppr expr_ty + = vcat [hsep [ptext (sLit "A variable has unboxed tuple type:"), ppr binder], + hsep [ptext (sLit "Binder's type:"), ppr (idType binder)]] + +mkCastErr :: Type -> Type -> Message +mkCastErr from_ty expr_ty + = vcat [ptext (sLit "From-type of Cast differs from type of enclosed expression"), + ptext (sLit "From-type:") <+> ppr from_ty, + ptext (sLit "Type of enclosed expr:") <+> ppr expr_ty ] -mkStrangeTyMsg e - = ptext SLIT("Type where expression expected:") <+> ppr e +dupVars :: [[Var]] -> Message +dupVars vars + = hang (ptext (sLit "Duplicate variables brought into scope")) + 2 (ppr vars) \end{code}