-- -- (c) The University of Glasgow 2002-2006 -- -- Functions over HsSyn specialised to RdrName. {-# LANGUAGE CPP #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE MagicHash #-} {-# LANGUAGE ViewPatterns #-} module RdrHsSyn ( mkHsOpApp, mkHsIntegral, mkHsFractional, mkHsIsString, mkHsDo, mkSpliceDecl, mkRoleAnnotDecl, mkClassDecl, mkTyData, mkDataFamInst, mkTySynonym, mkTyFamInstEqn, mkTyFamInst, mkFamDecl, mkLHsSigType, mkInlinePragma, mkPatSynMatchGroup, mkRecConstrOrUpdate, -- HsExp -> [HsFieldUpdate] -> P HsExp mkTyClD, mkInstD, mkRdrRecordCon, mkRdrRecordUpd, setRdrNameSpace, filterCTuple, cvBindGroup, cvBindsAndSigs, cvTopDecls, placeHolderPunRhs, -- Stuff to do with Foreign declarations mkImport, parseCImport, mkExport, mkExtName, -- RdrName -> CLabelString mkGadtDecl, -- [Located RdrName] -> LHsType RdrName -> ConDecl RdrName mkConDeclH98, mkATDefault, -- Bunch of functions in the parser monad for -- checking and constructing values checkBlockArguments, checkPrecP, -- Int -> P Int checkContext, -- HsType -> P HsContext checkPattern, -- HsExp -> P HsPat bang_RDR, checkPatterns, -- SrcLoc -> [HsExp] -> P [HsPat] checkMonadComp, -- P (HsStmtContext RdrName) checkCommand, -- LHsExpr RdrName -> P (LHsCmd RdrName) checkValDef, -- (SrcLoc, HsExp, HsRhs, [HsDecl]) -> P HsDecl checkValSigLhs, checkDoAndIfThenElse, LRuleTyTmVar, RuleTyTmVar(..), mkRuleBndrs, mkRuleTyVarBndrs, checkRuleTyVarBndrNames, checkRecordSyntax, checkEmptyGADTs, parseErrorSDoc, hintBangPat, TyEl(..), mergeOps, mergeDataCon, -- Help with processing exports ImpExpSubSpec(..), ImpExpQcSpec(..), mkModuleImpExp, mkTypeImpExp, mkImpExpSubSpec, checkImportSpec, -- Warnings and errors warnStarIsType, failOpFewArgs, SumOrTuple (..), mkSumOrTuple ) where import GhcPrelude import HsSyn -- Lots of it import TyCon ( TyCon, isTupleTyCon, tyConSingleDataCon_maybe ) import DataCon ( DataCon, dataConTyCon ) import ConLike ( ConLike(..) ) import CoAxiom ( Role, fsFromRole ) import RdrName import Name import BasicTypes import TcEvidence ( idHsWrapper ) import Lexer import Lexeme ( isLexCon ) import Type ( TyThing(..), funTyCon ) import TysWiredIn ( cTupleTyConName, tupleTyCon, tupleDataCon, nilDataConName, nilDataConKey, listTyConName, listTyConKey, eqTyCon_RDR, tupleTyConName, cTupleTyConNameArity_maybe ) import ForeignCall import PrelNames ( forall_tv_RDR, allNameStrings ) import SrcLoc import Unique ( hasKey ) import OrdList ( OrdList, fromOL ) import Bag ( emptyBag, consBag ) import Outputable import FastString import Maybes import Util import ApiAnnotation import Data.List import DynFlags ( WarningFlag(..) ) import Control.Monad import Text.ParserCombinators.ReadP as ReadP import Data.Char import qualified Data.Monoid as Monoid import Data.Data ( dataTypeOf, fromConstr, dataTypeConstrs ) #include "HsVersions.h" {- ********************************************************************** Construction functions for Rdr stuff ********************************************************************* -} -- | mkClassDecl builds a RdrClassDecl, filling in the names for tycon and -- datacon by deriving them from the name of the class. We fill in the names -- for the tycon and datacon corresponding to the class, by deriving them -- from the name of the class itself. This saves recording the names in the -- interface file (which would be equally good). -- Similarly for mkConDecl, mkClassOpSig and default-method names. -- *** See Note [The Naming story] in HsDecls **** mkTyClD :: LTyClDecl (GhcPass p) -> LHsDecl (GhcPass p) mkTyClD (dL->L loc d) = cL loc (TyClD noExt d) mkInstD :: LInstDecl (GhcPass p) -> LHsDecl (GhcPass p) mkInstD (dL->L loc d) = cL loc (InstD noExt d) mkClassDecl :: SrcSpan -> Located (Maybe (LHsContext GhcPs), LHsType GhcPs) -> Located (a,[LHsFunDep GhcPs]) -> OrdList (LHsDecl GhcPs) -> P (LTyClDecl GhcPs) mkClassDecl loc (dL->L _ (mcxt, tycl_hdr)) fds where_cls = do { (binds, sigs, ats, at_insts, _, docs) <- cvBindsAndSigs where_cls ; let cxt = fromMaybe (noLoc []) mcxt ; (cls, tparams, fixity, ann) <- checkTyClHdr True tycl_hdr ; mapM_ (\a -> a loc) ann -- Add any API Annotations to the top SrcSpan ; tyvars <- checkTyVarsP (text "class") whereDots cls tparams ; (at_defs, anns) <- fmap unzip $ mapM (eitherToP . mkATDefault) at_insts ; sequence_ anns ; return (cL loc (ClassDecl { tcdCExt = noExt, tcdCtxt = cxt , tcdLName = cls, tcdTyVars = tyvars , tcdFixity = fixity , tcdFDs = snd (unLoc fds) , tcdSigs = mkClassOpSigs sigs , tcdMeths = binds , tcdATs = ats, tcdATDefs = at_defs , tcdDocs = docs })) } mkATDefault :: LTyFamInstDecl GhcPs -> Either (SrcSpan, SDoc) (LTyFamDefltEqn GhcPs, P ()) -- ^ Take a type-family instance declaration and turn it into -- a type-family default equation for a class declaration. -- We parse things as the former and use this function to convert to the latter -- -- We use the Either monad because this also called from "Convert". -- -- The @P ()@ we return corresponds represents an action which will add -- some necessary paren annotations to the parsing context. Naturally, this -- is not something that the "Convert" use cares about. mkATDefault (dL->L loc (TyFamInstDecl { tfid_eqn = HsIB { hsib_body = e }})) | FamEqn { feqn_tycon = tc, feqn_bndrs = bndrs, feqn_pats = pats , feqn_fixity = fixity, feqn_rhs = rhs } <- e = do { (tvs, anns) <- checkTyVars (text "default") equalsDots tc pats ; let f = cL loc (FamEqn { feqn_ext = noExt , feqn_tycon = tc , feqn_bndrs = ASSERT( isNothing bndrs ) Nothing , feqn_pats = tvs , feqn_fixity = fixity , feqn_rhs = rhs }) ; pure (f, anns) } mkATDefault (dL->L _ (TyFamInstDecl (HsIB _ (XFamEqn _)))) = panic "mkATDefault" mkATDefault (dL->L _ (TyFamInstDecl (XHsImplicitBndrs _))) = panic "mkATDefault" mkATDefault _ = panic "mkATDefault: Impossible Match" -- due to #15884 mkTyData :: SrcSpan -> NewOrData -> Maybe (Located CType) -> Located (Maybe (LHsContext GhcPs), LHsType GhcPs) -> Maybe (LHsKind GhcPs) -> [LConDecl GhcPs] -> HsDeriving GhcPs -> P (LTyClDecl GhcPs) mkTyData loc new_or_data cType (dL->L _ (mcxt, tycl_hdr)) ksig data_cons maybe_deriv = do { (tc, tparams, fixity, ann) <- checkTyClHdr False tycl_hdr ; mapM_ (\a -> a loc) ann -- Add any API Annotations to the top SrcSpan ; tyvars <- checkTyVarsP (ppr new_or_data) equalsDots tc tparams ; defn <- mkDataDefn new_or_data cType mcxt ksig data_cons maybe_deriv ; return (cL loc (DataDecl { tcdDExt = noExt, tcdLName = tc, tcdTyVars = tyvars, tcdFixity = fixity, tcdDataDefn = defn })) } mkDataDefn :: NewOrData -> Maybe (Located CType) -> Maybe (LHsContext GhcPs) -> Maybe (LHsKind GhcPs) -> [LConDecl GhcPs] -> HsDeriving GhcPs -> P (HsDataDefn GhcPs) mkDataDefn new_or_data cType mcxt ksig data_cons maybe_deriv = do { checkDatatypeContext mcxt ; let cxt = fromMaybe (noLoc []) mcxt ; return (HsDataDefn { dd_ext = noExt , dd_ND = new_or_data, dd_cType = cType , dd_ctxt = cxt , dd_cons = data_cons , dd_kindSig = ksig , dd_derivs = maybe_deriv }) } mkTySynonym :: SrcSpan -> LHsType GhcPs -- LHS -> LHsType GhcPs -- RHS -> P (LTyClDecl GhcPs) mkTySynonym loc lhs rhs = do { (tc, tparams, fixity, ann) <- checkTyClHdr False lhs ; mapM_ (\a -> a loc) ann -- Add any API Annotations to the top SrcSpan ; tyvars <- checkTyVarsP (text "type") equalsDots tc tparams ; return (cL loc (SynDecl { tcdSExt = noExt , tcdLName = tc, tcdTyVars = tyvars , tcdFixity = fixity , tcdRhs = rhs })) } mkTyFamInstEqn :: Maybe [LHsTyVarBndr GhcPs] -> LHsType GhcPs -> LHsType GhcPs -> P (TyFamInstEqn GhcPs,[AddAnn]) mkTyFamInstEqn bndrs lhs rhs = do { (tc, tparams, fixity, ann) <- checkTyClHdr False lhs ; return (mkHsImplicitBndrs (FamEqn { feqn_ext = noExt , feqn_tycon = tc , feqn_bndrs = bndrs , feqn_pats = tparams , feqn_fixity = fixity , feqn_rhs = rhs }), ann) } mkDataFamInst :: SrcSpan -> NewOrData -> Maybe (Located CType) -> Located ( Maybe (LHsContext GhcPs), Maybe [LHsTyVarBndr GhcPs] , LHsType GhcPs) -> Maybe (LHsKind GhcPs) -> [LConDecl GhcPs] -> HsDeriving GhcPs -> P (LInstDecl GhcPs) mkDataFamInst loc new_or_data cType (dL->L _ (mcxt, bndrs, tycl_hdr)) ksig data_cons maybe_deriv = do { (tc, tparams, fixity, ann) <- checkTyClHdr False tycl_hdr ; mapM_ (\a -> a loc) ann -- Add any API Annotations to the top SrcSpan ; defn <- mkDataDefn new_or_data cType mcxt ksig data_cons maybe_deriv ; return (cL loc (DataFamInstD noExt (DataFamInstDecl (mkHsImplicitBndrs (FamEqn { feqn_ext = noExt , feqn_tycon = tc , feqn_bndrs = bndrs , feqn_pats = tparams , feqn_fixity = fixity , feqn_rhs = defn }))))) } mkTyFamInst :: SrcSpan -> TyFamInstEqn GhcPs -> P (LInstDecl GhcPs) mkTyFamInst loc eqn = return (cL loc (TyFamInstD noExt (TyFamInstDecl eqn))) mkFamDecl :: SrcSpan -> FamilyInfo GhcPs -> LHsType GhcPs -- LHS -> Located (FamilyResultSig GhcPs) -- Optional result signature -> Maybe (LInjectivityAnn GhcPs) -- Injectivity annotation -> P (LTyClDecl GhcPs) mkFamDecl loc info lhs ksig injAnn = do { (tc, tparams, fixity, ann) <- checkTyClHdr False lhs ; mapM_ (\a -> a loc) ann -- Add any API Annotations to the top SrcSpan ; tyvars <- checkTyVarsP (ppr info) equals_or_where tc tparams ; return (cL loc (FamDecl noExt (FamilyDecl { fdExt = noExt , fdInfo = info, fdLName = tc , fdTyVars = tyvars , fdFixity = fixity , fdResultSig = ksig , fdInjectivityAnn = injAnn }))) } where equals_or_where = case info of DataFamily -> empty OpenTypeFamily -> empty ClosedTypeFamily {} -> whereDots mkSpliceDecl :: LHsExpr GhcPs -> HsDecl GhcPs -- If the user wrote -- [pads| ... ] then return a QuasiQuoteD -- $(e) then return a SpliceD -- but if she wrote, say, -- f x then behave as if she'd written $(f x) -- ie a SpliceD -- -- Typed splices are not allowed at the top level, thus we do not represent them -- as spliced declaration. See #10945 mkSpliceDecl lexpr@(dL->L loc expr) | HsSpliceE _ splice@(HsUntypedSplice {}) <- expr = SpliceD noExt (SpliceDecl noExt (cL loc splice) ExplicitSplice) | HsSpliceE _ splice@(HsQuasiQuote {}) <- expr = SpliceD noExt (SpliceDecl noExt (cL loc splice) ExplicitSplice) | otherwise = SpliceD noExt (SpliceDecl noExt (cL loc (mkUntypedSplice NoParens lexpr)) ImplicitSplice) mkRoleAnnotDecl :: SrcSpan -> Located RdrName -- type being annotated -> [Located (Maybe FastString)] -- roles -> P (LRoleAnnotDecl GhcPs) mkRoleAnnotDecl loc tycon roles = do { roles' <- mapM parse_role roles ; return $ cL loc $ RoleAnnotDecl noExt tycon roles' } where role_data_type = dataTypeOf (undefined :: Role) all_roles = map fromConstr $ dataTypeConstrs role_data_type possible_roles = [(fsFromRole role, role) | role <- all_roles] parse_role (dL->L loc_role Nothing) = return $ cL loc_role Nothing parse_role (dL->L loc_role (Just role)) = case lookup role possible_roles of Just found_role -> return $ cL loc_role $ Just found_role Nothing -> let nearby = fuzzyLookup (unpackFS role) (mapFst unpackFS possible_roles) in parseErrorSDoc loc_role (text "Illegal role name" <+> quotes (ppr role) $$ suggestions nearby) parse_role _ = panic "parse_role: Impossible Match" -- due to #15884 suggestions [] = empty suggestions [r] = text "Perhaps you meant" <+> quotes (ppr r) -- will this last case ever happen?? suggestions list = hang (text "Perhaps you meant one of these:") 2 (pprWithCommas (quotes . ppr) list) {- ********************************************************************** #cvBinds-etc# Converting to @HsBinds@, etc. ********************************************************************* -} -- | Function definitions are restructured here. Each is assumed to be recursive -- initially, and non recursive definitions are discovered by the dependency -- analyser. -- | Groups together bindings for a single function cvTopDecls :: OrdList (LHsDecl GhcPs) -> [LHsDecl GhcPs] cvTopDecls decls = go (fromOL decls) where go :: [LHsDecl GhcPs] -> [LHsDecl GhcPs] go [] = [] go ((dL->L l (ValD x b)) : ds) = cL l' (ValD x b') : go ds' where (dL->L l' b', ds') = getMonoBind (cL l b) ds go (d : ds) = d : go ds -- Declaration list may only contain value bindings and signatures. cvBindGroup :: OrdList (LHsDecl GhcPs) -> P (HsValBinds GhcPs) cvBindGroup binding = do { (mbs, sigs, fam_ds, tfam_insts , dfam_insts, _) <- cvBindsAndSigs binding ; ASSERT( null fam_ds && null tfam_insts && null dfam_insts) return $ ValBinds noExt mbs sigs } cvBindsAndSigs :: OrdList (LHsDecl GhcPs) -> P (LHsBinds GhcPs, [LSig GhcPs], [LFamilyDecl GhcPs] , [LTyFamInstDecl GhcPs], [LDataFamInstDecl GhcPs], [LDocDecl]) -- Input decls contain just value bindings and signatures -- and in case of class or instance declarations also -- associated type declarations. They might also contain Haddock comments. cvBindsAndSigs fb = go (fromOL fb) where go [] = return (emptyBag, [], [], [], [], []) go ((dL->L l (ValD _ b)) : ds) = do { (bs, ss, ts, tfis, dfis, docs) <- go ds' ; return (b' `consBag` bs, ss, ts, tfis, dfis, docs) } where (b', ds') = getMonoBind (cL l b) ds go ((dL->L l decl) : ds) = do { (bs, ss, ts, tfis, dfis, docs) <- go ds ; case decl of SigD _ s -> return (bs, cL l s : ss, ts, tfis, dfis, docs) TyClD _ (FamDecl _ t) -> return (bs, ss, cL l t : ts, tfis, dfis, docs) InstD _ (TyFamInstD { tfid_inst = tfi }) -> return (bs, ss, ts, cL l tfi : tfis, dfis, docs) InstD _ (DataFamInstD { dfid_inst = dfi }) -> return (bs, ss, ts, tfis, cL l dfi : dfis, docs) DocD _ d -> return (bs, ss, ts, tfis, dfis, cL l d : docs) SpliceD _ d -> parseErrorSDoc l $ hang (text "Declaration splices are allowed only" <+> text "at the top level:") 2 (ppr d) _ -> pprPanic "cvBindsAndSigs" (ppr decl) } ----------------------------------------------------------------------------- -- Group function bindings into equation groups getMonoBind :: LHsBind GhcPs -> [LHsDecl GhcPs] -> (LHsBind GhcPs, [LHsDecl GhcPs]) -- Suppose (b',ds') = getMonoBind b ds -- ds is a list of parsed bindings -- b is a MonoBinds that has just been read off the front -- Then b' is the result of grouping more equations from ds that -- belong with b into a single MonoBinds, and ds' is the depleted -- list of parsed bindings. -- -- All Haddock comments between equations inside the group are -- discarded. -- -- No AndMonoBinds or EmptyMonoBinds here; just single equations getMonoBind (dL->L loc1 (FunBind { fun_id = fun_id1@(dL->L _ f1) , fun_matches = MG { mg_alts = (dL->L _ mtchs1) } })) binds | has_args mtchs1 = go mtchs1 loc1 binds [] where go mtchs loc ((dL->L loc2 (ValD _ (FunBind { fun_id = (dL->L _ f2) , fun_matches = MG { mg_alts = (dL->L _ mtchs2) } }))) : binds) _ | f1 == f2 = go (mtchs2 ++ mtchs) (combineSrcSpans loc loc2) binds [] go mtchs loc (doc_decl@(dL->L loc2 (DocD {})) : binds) doc_decls = let doc_decls' = doc_decl : doc_decls in go mtchs (combineSrcSpans loc loc2) binds doc_decls' go mtchs loc binds doc_decls = ( cL loc (makeFunBind fun_id1 (reverse mtchs)) , (reverse doc_decls) ++ binds) -- Reverse the final matches, to get it back in the right order -- Do the same thing with the trailing doc comments getMonoBind bind binds = (bind, binds) has_args :: [LMatch GhcPs (LHsExpr GhcPs)] -> Bool has_args [] = panic "RdrHsSyn:has_args" has_args ((dL->L _ (Match { m_pats = args })) : _) = not (null args) -- Don't group together FunBinds if they have -- no arguments. This is necessary now that variable bindings -- with no arguments are now treated as FunBinds rather -- than pattern bindings (tests/rename/should_fail/rnfail002). has_args ((dL->L _ (XMatch _)) : _) = panic "has_args" has_args (_ : _) = panic "has_args:Impossible Match" -- due to #15884 {- ********************************************************************** #PrefixToHS-utils# Utilities for conversion ********************************************************************* -} {- Note [Parsing data constructors is hard] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The problem with parsing data constructors is that they look a lot like types. Compare: (s1) data T = C t1 t2 (s2) type T = C t1 t2 Syntactically, there's little difference between these declarations, except in (s1) 'C' is a data constructor, but in (s2) 'C' is a type constructor. This similarity would pose no problem if we knew ahead of time if we are parsing a type or a constructor declaration. Looking at (s1) and (s2), a simple (but wrong!) rule comes to mind: in 'data' declarations assume we are parsing data constructors, and in other contexts (e.g. 'type' declarations) assume we are parsing type constructors. This simple rule does not work because of two problematic cases: (p1) data T = C t1 t2 :+ t3 (p2) data T = C t1 t2 => t3 In (p1) we encounter (:+) and it turns out we are parsing an infix data declaration, so (C t1 t2) is a type and 'C' is a type constructor. In (p2) we encounter (=>) and it turns out we are parsing an existential context, so (C t1 t2) is a constraint and 'C' is a type constructor. As the result, in order to determine whether (C t1 t2) declares a data constructor, a type, or a context, we would need unlimited lookahead which 'happy' is not so happy with. To further complicate matters, the interpretation of (!) and (~) is different in constructors and types: (b1) type T = C ! D (b2) data T = C ! D (b3) data T = C ! D => E In (b1) and (b3), (!) is a type operator with two arguments: 'C' and 'D'. At the same time, in (b2) it is a strictness annotation: 'C' is a data constructor with a single strict argument 'D'. For the programmer, these cases are usually easy to tell apart due to whitespace conventions: (b2) data T = C !D -- no space after the bang hints that -- it is a strictness annotation For the parser, on the other hand, this whitespace does not matter. We cannot tell apart (b2) from (b3) until we encounter (=>), so it requires unlimited lookahead. The solution that accounts for all of these issues is to initially parse data declarations and types as a reversed list of TyEl: data TyEl = TyElOpr RdrName | TyElOpd (HsType GhcPs) | TyElBang | TyElTilde | ... For example, both occurences of (C ! D) in the following example are parsed into equal lists of TyEl: data T = C ! D => C ! D results in [ TyElOpd (HsTyVar "D") , TyElBang , TyElOpd (HsTyVar "C") ] Note that elements are in reverse order. Also, 'C' is parsed as a type constructor (HsTyVar) even when it is a data constructor. We fix this in `tyConToDataCon`. By the time the list of TyEl is assembled, we have looked ahead enough to decide whether to reduce using `mergeOps` (for types) or `mergeDataCon` (for data constructors). These functions are where the actual job of parsing is done. -} -- | Reinterpret a type constructor, including type operators, as a data -- constructor. -- See Note [Parsing data constructors is hard] tyConToDataCon :: SrcSpan -> RdrName -> Either (SrcSpan, SDoc) (Located RdrName) tyConToDataCon loc tc | isTcOcc occ || isDataOcc occ , isLexCon (occNameFS occ) = return (cL loc (setRdrNameSpace tc srcDataName)) | otherwise = Left (loc, msg $$ extra) where occ = rdrNameOcc tc msg = text "Not a data constructor:" <+> quotes (ppr tc) extra | tc == forall_tv_RDR = text "Perhaps you intended to use ExistentialQuantification" | otherwise = empty mkPatSynMatchGroup :: Located RdrName -> Located (OrdList (LHsDecl GhcPs)) -> P (MatchGroup GhcPs (LHsExpr GhcPs)) mkPatSynMatchGroup (dL->L loc patsyn_name) (dL->L _ decls) = do { matches <- mapM fromDecl (fromOL decls) ; when (null matches) (wrongNumberErr loc) ; return $ mkMatchGroup FromSource matches } where fromDecl (dL->L loc decl@(ValD _ (PatBind _ pat@(dL->L _ (ConPatIn ln@(dL->L _ name) details)) rhs _))) = do { unless (name == patsyn_name) $ wrongNameBindingErr loc decl ; match <- case details of PrefixCon pats -> return $ Match { m_ext = noExt , m_ctxt = ctxt, m_pats = pats , m_grhss = rhs } where ctxt = FunRhs { mc_fun = ln , mc_fixity = Prefix , mc_strictness = NoSrcStrict } InfixCon p1 p2 -> return $ Match { m_ext = noExt , m_ctxt = ctxt , m_pats = [p1, p2] , m_grhss = rhs } where ctxt = FunRhs { mc_fun = ln , mc_fixity = Infix , mc_strictness = NoSrcStrict } RecCon{} -> recordPatSynErr loc pat ; return $ cL loc match } fromDecl (dL->L loc decl) = extraDeclErr loc decl extraDeclErr loc decl = parseErrorSDoc loc $ text "pattern synonym 'where' clause must contain a single binding:" $$ ppr decl wrongNameBindingErr loc decl = parseErrorSDoc loc $ text "pattern synonym 'where' clause must bind the pattern synonym's name" <+> quotes (ppr patsyn_name) $$ ppr decl wrongNumberErr loc = parseErrorSDoc loc $ text "pattern synonym 'where' clause cannot be empty" $$ text "In the pattern synonym declaration for: " <+> ppr (patsyn_name) recordPatSynErr :: SrcSpan -> LPat GhcPs -> P a recordPatSynErr loc pat = parseErrorSDoc loc $ text "record syntax not supported for pattern synonym declarations:" $$ ppr pat mkConDeclH98 :: Located RdrName -> Maybe [LHsTyVarBndr GhcPs] -> Maybe (LHsContext GhcPs) -> HsConDeclDetails GhcPs -> ConDecl GhcPs mkConDeclH98 name mb_forall mb_cxt args = ConDeclH98 { con_ext = noExt , con_name = name , con_forall = noLoc $ isJust mb_forall , con_ex_tvs = mb_forall `orElse` [] , con_mb_cxt = mb_cxt , con_args = args' , con_doc = Nothing } where args' = nudgeHsSrcBangs args mkGadtDecl :: [Located RdrName] -> LHsType GhcPs -- Always a HsForAllTy -> (ConDecl GhcPs, [AddAnn]) mkGadtDecl names ty = (ConDeclGADT { con_g_ext = noExt , con_names = names , con_forall = cL l $ isLHsForAllTy ty' , con_qvars = mkHsQTvs tvs , con_mb_cxt = mcxt , con_args = args' , con_res_ty = res_ty , con_doc = Nothing } , anns1 ++ anns2) where (ty'@(dL->L l _),anns1) = peel_parens ty [] (tvs, rho) = splitLHsForAllTy ty' (mcxt, tau, anns2) = split_rho rho [] split_rho (dL->L _ (HsQualTy { hst_ctxt = cxt, hst_body = tau })) ann = (Just cxt, tau, ann) split_rho (dL->L l (HsParTy _ ty)) ann = split_rho ty (ann++mkParensApiAnn l) split_rho tau ann = (Nothing, tau, ann) (args, res_ty) = split_tau tau args' = nudgeHsSrcBangs args -- See Note [GADT abstract syntax] in HsDecls split_tau (dL->L _ (HsFunTy _ (dL->L loc (HsRecTy _ rf)) res_ty)) = (RecCon (cL loc rf), res_ty) split_tau tau = (PrefixCon [], tau) peel_parens (dL->L l (HsParTy _ ty)) ann = peel_parens ty (ann++mkParensApiAnn l) peel_parens ty ann = (ty, ann) nudgeHsSrcBangs :: HsConDeclDetails GhcPs -> HsConDeclDetails GhcPs -- ^ This function ensures that fields with strictness or packedness -- annotations put these annotations on an outer 'HsBangTy'. -- -- The problem is that in the parser, strictness and packedness annotations -- bind more tightly that docstrings. However, the expectation downstream of -- the parser (by functions such as 'getBangType' and 'getBangStrictness') -- is that docstrings bind more tightly so that 'HsBangTy' may end up as the -- top-level type. -- -- See #15206 nudgeHsSrcBangs details = case details of PrefixCon as -> PrefixCon (map go as) RecCon r -> RecCon r InfixCon a1 a2 -> InfixCon (go a1) (go a2) where go (dL->L l (HsDocTy _ (dL->L _ (HsBangTy _ s lty)) lds)) = cL l (HsBangTy noExt s (addCLoc lty lds (HsDocTy noExt lty lds))) go lty = lty setRdrNameSpace :: RdrName -> NameSpace -> RdrName -- ^ This rather gruesome function is used mainly by the parser. -- When parsing: -- -- > data T a = T | T1 Int -- -- we parse the data constructors as /types/ because of parser ambiguities, -- so then we need to change the /type constr/ to a /data constr/ -- -- The exact-name case /can/ occur when parsing: -- -- > data [] a = [] | a : [a] -- -- For the exact-name case we return an original name. setRdrNameSpace (Unqual occ) ns = Unqual (setOccNameSpace ns occ) setRdrNameSpace (Qual m occ) ns = Qual m (setOccNameSpace ns occ) setRdrNameSpace (Orig m occ) ns = Orig m (setOccNameSpace ns occ) setRdrNameSpace (Exact n) ns | Just thing <- wiredInNameTyThing_maybe n = setWiredInNameSpace thing ns -- Preserve Exact Names for wired-in things, -- notably tuples and lists | isExternalName n = Orig (nameModule n) occ | otherwise -- This can happen when quoting and then -- splicing a fixity declaration for a type = Exact (mkSystemNameAt (nameUnique n) occ (nameSrcSpan n)) where occ = setOccNameSpace ns (nameOccName n) setWiredInNameSpace :: TyThing -> NameSpace -> RdrName setWiredInNameSpace (ATyCon tc) ns | isDataConNameSpace ns = ty_con_data_con tc | isTcClsNameSpace ns = Exact (getName tc) -- No-op setWiredInNameSpace (AConLike (RealDataCon dc)) ns | isTcClsNameSpace ns = data_con_ty_con dc | isDataConNameSpace ns = Exact (getName dc) -- No-op setWiredInNameSpace thing ns = pprPanic "setWiredinNameSpace" (pprNameSpace ns <+> ppr thing) ty_con_data_con :: TyCon -> RdrName ty_con_data_con tc | isTupleTyCon tc , Just dc <- tyConSingleDataCon_maybe tc = Exact (getName dc) | tc `hasKey` listTyConKey = Exact nilDataConName | otherwise -- See Note [setRdrNameSpace for wired-in names] = Unqual (setOccNameSpace srcDataName (getOccName tc)) data_con_ty_con :: DataCon -> RdrName data_con_ty_con dc | let tc = dataConTyCon dc , isTupleTyCon tc = Exact (getName tc) | dc `hasKey` nilDataConKey = Exact listTyConName | otherwise -- See Note [setRdrNameSpace for wired-in names] = Unqual (setOccNameSpace tcClsName (getOccName dc)) -- | Replaces constraint tuple names with corresponding boxed ones. filterCTuple :: RdrName -> RdrName filterCTuple (Exact n) | Just arity <- cTupleTyConNameArity_maybe n = Exact $ tupleTyConName BoxedTuple arity filterCTuple rdr = rdr {- Note [setRdrNameSpace for wired-in names] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In GHC.Types, which declares (:), we have infixr 5 : The ambiguity about which ":" is meant is resolved by parsing it as a data constructor, but then using dataTcOccs to try the type constructor too; and that in turn calls setRdrNameSpace to change the name-space of ":" to tcClsName. There isn't a corresponding ":" type constructor, but it's painful to make setRdrNameSpace partial, so we just make an Unqual name instead. It really doesn't matter! -} checkTyVarsP :: SDoc -> SDoc -> Located RdrName -> [LHsTypeArg GhcPs] -> P (LHsQTyVars GhcPs) -- Same as checkTyVars, but in the P monad checkTyVarsP pp_what equals_or_where tc tparms = do { let checkedTvs = checkTyVars pp_what equals_or_where tc tparms ; (tvs, anns) <- eitherToP checkedTvs ; anns ; pure tvs } eitherToP :: Either (SrcSpan, SDoc) a -> P a -- Adapts the Either monad to the P monad eitherToP (Left (loc, doc)) = parseErrorSDoc loc doc eitherToP (Right thing) = return thing checkTyVars :: SDoc -> SDoc -> Located RdrName -> [LHsTypeArg GhcPs] -> Either (SrcSpan, SDoc) ( LHsQTyVars GhcPs -- the synthesized type variables , P () ) -- action which adds annotations -- ^ Check whether the given list of type parameters are all type variables -- (possibly with a kind signature). -- We use the Either monad because it's also called (via 'mkATDefault') from -- "Convert". checkTyVars pp_what equals_or_where tc tparms = do { (tvs, anns) <- fmap unzip $ mapM check tparms ; return (mkHsQTvs tvs, sequence_ anns) } where check (HsTypeArg ki@(L loc _)) = Left (loc, vcat [ text "Unexpected type application" <+> text "@" <> ppr ki , text "In the" <+> pp_what <+> ptext (sLit "declaration for") <+> quotes (ppr tc)]) check (HsValArg ty) = chkParens [] ty check (HsArgPar sp) = Left (sp, vcat [text "Malformed" <+> pp_what <+> text "declaration for" <+> quotes (ppr tc)]) -- Keep around an action for adjusting the annotations of extra parens chkParens :: [AddAnn] -> LHsType GhcPs -> Either (SrcSpan, SDoc) (LHsTyVarBndr GhcPs, P ()) chkParens acc (dL->L l (HsParTy _ ty)) = chkParens (mkParensApiAnn l ++ acc) ty chkParens acc ty = case chk ty of Left err -> Left err Right tv@(dL->L l _) -> Right (tv, addAnnsAt l (reverse acc)) -- Check that the name space is correct! chk (dL->L l (HsKindSig _ (dL->L lv (HsTyVar _ _ (dL->L _ tv))) k)) | isRdrTyVar tv = return (cL l (KindedTyVar noExt (cL lv tv) k)) chk (dL->L l (HsTyVar _ _ (dL->L ltv tv))) | isRdrTyVar tv = return (cL l (UserTyVar noExt (cL ltv tv))) chk t@(dL->L loc _) = Left (loc, vcat [ text "Unexpected type" <+> quotes (ppr t) , text "In the" <+> pp_what <+> ptext (sLit "declaration for") <+> quotes tc' , vcat[ (text "A" <+> pp_what <+> ptext (sLit "declaration should have form")) , nest 2 (pp_what <+> tc' <+> hsep (map text (takeList tparms allNameStrings)) <+> equals_or_where) ] ]) -- Avoid printing a constraint tuple in the error message. Print -- a plain old tuple instead (since that's what the user probably -- wrote). See #14907 tc' = ppr $ fmap filterCTuple tc whereDots, equalsDots :: SDoc -- Second argument to checkTyVars whereDots = text "where ..." equalsDots = text "= ..." checkDatatypeContext :: Maybe (LHsContext GhcPs) -> P () checkDatatypeContext Nothing = return () checkDatatypeContext (Just c) = do allowed <- getBit DatatypeContextsBit unless allowed $ parseErrorSDoc (getLoc c) (text "Illegal datatype context (use DatatypeContexts):" <+> pprLHsContext c) type LRuleTyTmVar = Located RuleTyTmVar data RuleTyTmVar = RuleTyTmVar (Located RdrName) (Maybe (LHsType GhcPs)) -- ^ Essentially a wrapper for a @RuleBndr GhcPs@ -- turns RuleTyTmVars into RuleBnrs - this is straightforward mkRuleBndrs :: [LRuleTyTmVar] -> [LRuleBndr GhcPs] mkRuleBndrs = fmap (fmap cvt_one) where cvt_one (RuleTyTmVar v Nothing) = RuleBndr noExt v cvt_one (RuleTyTmVar v (Just sig)) = RuleBndrSig noExt v (mkLHsSigWcType sig) -- turns RuleTyTmVars into HsTyVarBndrs - this is more interesting mkRuleTyVarBndrs :: [LRuleTyTmVar] -> [LHsTyVarBndr GhcPs] mkRuleTyVarBndrs = fmap (fmap cvt_one) where cvt_one (RuleTyTmVar v Nothing) = UserTyVar noExt (fmap tm_to_ty v) cvt_one (RuleTyTmVar v (Just sig)) = KindedTyVar noExt (fmap tm_to_ty v) sig -- takes something in namespace 'varName' to something in namespace 'tvName' tm_to_ty (Unqual occ) = Unqual (setOccNameSpace tvName occ) tm_to_ty _ = panic "mkRuleTyVarBndrs" -- See note [Parsing explicit foralls in Rules] in Parser.y checkRuleTyVarBndrNames :: [LHsTyVarBndr GhcPs] -> P () checkRuleTyVarBndrNames = mapM_ (check . fmap hsTyVarName) where check (dL->L loc (Unqual occ)) = do when ((occNameString occ ==) `any` ["forall","family","role"]) (parseErrorSDoc loc (text $ "parse error on input " ++ occNameString occ)) check _ = panic "checkRuleTyVarBndrNames" checkRecordSyntax :: Outputable a => Located a -> P (Located a) checkRecordSyntax lr@(dL->L loc r) = do allowed <- getBit TraditionalRecordSyntaxBit if allowed then return lr else parseErrorSDoc loc (text "Illegal record syntax (use TraditionalRecordSyntax):" <+> ppr r) -- | Check if the gadt_constrlist is empty. Only raise parse error for -- `data T where` to avoid affecting existing error message, see #8258. checkEmptyGADTs :: Located ([AddAnn], [LConDecl GhcPs]) -> P (Located ([AddAnn], [LConDecl GhcPs])) checkEmptyGADTs gadts@(dL->L span (_, [])) -- Empty GADT declaration. = do gadtSyntax <- getBit GadtSyntaxBit -- GADTs implies GADTSyntax if gadtSyntax then return gadts else parseErrorSDoc span $ vcat [ text "Illegal keyword 'where' in data declaration" , text "Perhaps you intended to use GADTs or a similar language" , text "extension to enable syntax: data T where" ] checkEmptyGADTs gadts = return gadts -- Ordinary GADT declaration. checkTyClHdr :: Bool -- True <=> class header -- False <=> type header -> LHsType GhcPs -> P (Located RdrName, -- the head symbol (type or class name) [LHsTypeArg GhcPs], -- parameters of head symbol LexicalFixity, -- the declaration is in infix format [AddAnn]) -- API Annotation for HsParTy when stripping parens -- Well-formedness check and decomposition of type and class heads. -- Decomposes T ty1 .. tyn into (T, [ty1, ..., tyn]) -- Int :*: Bool into (:*:, [Int, Bool]) -- returning the pieces checkTyClHdr is_cls ty = goL ty [] [] Prefix where goL (dL->L l ty) acc ann fix = go l ty acc ann fix -- workaround to define '*' despite StarIsType go _ (HsParTy _ (dL->L l (HsStarTy _ isUni))) acc ann fix = do { warnStarBndr l ; let name = mkOccName tcClsName (if isUni then "★" else "*") ; return (cL l (Unqual name), acc, fix, ann) } go l (HsTyVar _ _ (dL->L _ tc)) acc ann fix | isRdrTc tc = return (cL l tc, acc, fix, ann) go _ (HsOpTy _ t1 ltc@(dL->L _ tc) t2) acc ann _fix | isRdrTc tc = return (ltc, HsValArg t1:HsValArg t2:acc, Infix, ann) go l (HsParTy _ ty) acc ann fix = goL ty acc (ann ++mkParensApiAnn l) fix go _ (HsAppTy _ t1 t2) acc ann fix = goL t1 (HsValArg t2:acc) ann fix go _ (HsAppKindTy _ ty ki) acc ann fix = goL ty (HsTypeArg ki:acc) ann fix go l (HsTupleTy _ HsBoxedOrConstraintTuple ts) [] ann fix = return (cL l (nameRdrName tup_name), map HsValArg ts, fix, ann) where arity = length ts tup_name | is_cls = cTupleTyConName arity | otherwise = getName (tupleTyCon Boxed arity) -- See Note [Unit tuples] in HsTypes (TODO: is this still relevant?) go l _ _ _ _ = parseErrorSDoc l (text "Malformed head of type or class declaration:" <+> ppr ty) -- | Yield a parse error if we have a function applied directly to a do block -- etc. and BlockArguments is not enabled. checkBlockArguments :: LHsExpr GhcPs -> P () checkBlockArguments expr = case unLoc expr of HsDo _ DoExpr _ -> check "do block" HsDo _ MDoExpr _ -> check "mdo block" HsLam {} -> check "lambda expression" HsCase {} -> check "case expression" HsLamCase {} -> check "lambda-case expression" HsLet {} -> check "let expression" HsIf {} -> check "if expression" HsProc {} -> check "proc expression" _ -> return () where check element = do blockArguments <- getBit BlockArgumentsBit unless blockArguments $ parseErrorSDoc (getLoc expr) $ text "Unexpected " <> text element <> text " in function application:" $$ nest 4 (ppr expr) $$ text "You could write it with parentheses" $$ text "Or perhaps you meant to enable BlockArguments?" -- | Validate the context constraints and break up a context into a list -- of predicates. -- -- @ -- (Eq a, Ord b) --> [Eq a, Ord b] -- Eq a --> [Eq a] -- (Eq a) --> [Eq a] -- (((Eq a))) --> [Eq a] -- @ checkContext :: LHsType GhcPs -> P ([AddAnn],LHsContext GhcPs) checkContext (dL->L l orig_t) = check [] (cL l orig_t) where check anns (dL->L lp (HsTupleTy _ HsBoxedOrConstraintTuple ts)) -- (Eq a, Ord b) shows up as a tuple type. Only boxed tuples can -- be used as context constraints. = return (anns ++ mkParensApiAnn lp,cL l ts) -- Ditto () check anns (dL->L lp1 (HsParTy _ ty)) -- to be sure HsParTy doesn't get into the way = check anns' ty where anns' = if l == lp1 then anns else (anns ++ mkParensApiAnn lp1) -- no need for anns, returning original check _anns t = checkNoDocs msg t *> return ([],cL l [cL l orig_t]) msg = text "data constructor context" -- | Check recursively if there are any 'HsDocTy's in the given type. -- This only works on a subset of types produced by 'btype_no_ops' checkNoDocs :: SDoc -> LHsType GhcPs -> P () checkNoDocs msg ty = go ty where go (dL->L _ (HsAppKindTy _ ty ki)) = go ty *> go ki go (dL->L _ (HsAppTy _ t1 t2)) = go t1 *> go t2 go (dL->L l (HsDocTy _ t ds)) = parseErrorSDoc l $ hsep [ text "Unexpected haddock", quotes (ppr ds) , text "on", msg, quotes (ppr t) ] go _ = pure () -- ------------------------------------------------------------------------- -- Checking Patterns. -- We parse patterns as expressions and check for valid patterns below, -- converting the expression into a pattern at the same time. checkPattern :: SDoc -> LHsExpr GhcPs -> P (LPat GhcPs) checkPattern msg e = checkLPat msg e checkPatterns :: SDoc -> [LHsExpr GhcPs] -> P [LPat GhcPs] checkPatterns msg es = mapM (checkPattern msg) es checkLPat :: SDoc -> LHsExpr GhcPs -> P (LPat GhcPs) checkLPat msg e@(dL->L l _) = checkPat msg l e [] checkPat :: SDoc -> SrcSpan -> LHsExpr GhcPs -> [LPat GhcPs] -> P (LPat GhcPs) checkPat _ loc (dL->L l e@(HsVar _ (dL->L _ c))) args | isRdrDataCon c = return (cL loc (ConPatIn (cL l c) (PrefixCon args))) | not (null args) && patIsRec c = patFail (text "Perhaps you intended to use RecursiveDo") l e checkPat msg loc e args -- OK to let this happen even if bang-patterns -- are not enabled, because there is no valid -- non-bang-pattern parse of (C ! e) | Just (e', args') <- splitBang e = do { args'' <- checkPatterns msg args' ; checkPat msg loc e' (args'' ++ args) } checkPat msg loc (dL->L _ (HsApp _ f e)) args = do p <- checkLPat msg e checkPat msg loc f (p : args) checkPat msg loc (dL->L _ e) [] = do p <- checkAPat msg loc e return (cL loc p) checkPat msg loc e _ = patFail msg loc (unLoc e) checkAPat :: SDoc -> SrcSpan -> HsExpr GhcPs -> P (Pat GhcPs) checkAPat msg loc e0 = do nPlusKPatterns <- getBit NPlusKPatternsBit case e0 of EWildPat _ -> return (WildPat noExt) HsVar _ x -> return (VarPat noExt x) HsLit _ (HsStringPrim _ _) -- (#13260) -> parseErrorSDoc loc (text "Illegal unboxed string literal in pattern:" $$ ppr e0) HsLit _ l -> return (LitPat noExt l) -- Overloaded numeric patterns (e.g. f 0 x = x) -- Negation is recorded separately, so that the literal is zero or +ve -- NB. Negative *primitive* literals are already handled by the lexer HsOverLit _ pos_lit -> return (mkNPat (cL loc pos_lit) Nothing) NegApp _ (dL->L l (HsOverLit _ pos_lit)) _ -> return (mkNPat (cL l pos_lit) (Just noSyntaxExpr)) SectionR _ (dL->L lb (HsVar _ (dL->L _ bang))) e -- (! x) | bang == bang_RDR -> do { hintBangPat loc e0 ; e' <- checkLPat msg e ; addAnnotation loc AnnBang lb ; return (BangPat noExt e') } ELazyPat _ e -> checkLPat msg e >>= (return . (LazyPat noExt)) EAsPat _ n e -> checkLPat msg e >>= (return . (AsPat noExt) n) -- view pattern is well-formed if the pattern is EViewPat _ expr patE -> checkLPat msg patE >>= (return . (\p -> ViewPat noExt expr p)) ExprWithTySig _ e t -> do e <- checkLPat msg e return (SigPat noExt e t) -- n+k patterns OpApp _ (dL->L nloc (HsVar _ (dL->L _ n))) (dL->L _ (HsVar _ (dL->L _ plus))) (dL->L lloc (HsOverLit _ lit@(OverLit {ol_val = HsIntegral {}}))) | nPlusKPatterns && (plus == plus_RDR) -> return (mkNPlusKPat (cL nloc n) (cL lloc lit)) OpApp _ l (dL->L cl (HsVar _ (dL->L _ c))) r | isDataOcc (rdrNameOcc c) -> do l <- checkLPat msg l r <- checkLPat msg r return (ConPatIn (cL cl c) (InfixCon l r)) OpApp {} -> patFail msg loc e0 ExplicitList _ _ es -> do ps <- mapM (checkLPat msg) es return (ListPat noExt ps) HsPar _ e -> checkLPat msg e >>= (return . (ParPat noExt)) ExplicitTuple _ es b | all tupArgPresent es -> do ps <- mapM (checkLPat msg) [e | (dL->L _ (Present _ e)) <- es] return (TuplePat noExt ps b) | otherwise -> parseErrorSDoc loc (text "Illegal tuple section in pattern:" $$ ppr e0) ExplicitSum _ alt arity expr -> do p <- checkLPat msg expr return (SumPat noExt p alt arity) RecordCon { rcon_con_name = c, rcon_flds = HsRecFields fs dd } -> do fs <- mapM (checkPatField msg) fs return (ConPatIn c (RecCon (HsRecFields fs dd))) HsSpliceE _ s | not (isTypedSplice s) -> return (SplicePat noExt s) _ -> patFail msg loc e0 placeHolderPunRhs :: LHsExpr GhcPs -- The RHS of a punned record field will be filled in by the renamer -- It's better not to make it an error, in case we want to print it when -- debugging placeHolderPunRhs = noLoc (HsVar noExt (noLoc pun_RDR)) plus_RDR, bang_RDR, pun_RDR :: RdrName plus_RDR = mkUnqual varName (fsLit "+") -- Hack bang_RDR = mkUnqual varName (fsLit "!") -- Hack pun_RDR = mkUnqual varName (fsLit "pun-right-hand-side") checkPatField :: SDoc -> LHsRecField GhcPs (LHsExpr GhcPs) -> P (LHsRecField GhcPs (LPat GhcPs)) checkPatField msg (dL->L l fld) = do p <- checkLPat msg (hsRecFieldArg fld) return (cL l (fld { hsRecFieldArg = p })) patFail :: SDoc -> SrcSpan -> HsExpr GhcPs -> P a patFail msg loc e = parseErrorSDoc loc err where err = text "Parse error in pattern:" <+> ppr e $$ msg patIsRec :: RdrName -> Bool patIsRec e = e == mkUnqual varName (fsLit "rec") --------------------------------------------------------------------------- -- Check Equation Syntax checkValDef :: SDoc -> SrcStrictness -> LHsExpr GhcPs -> Maybe (LHsType GhcPs) -> Located (a,GRHSs GhcPs (LHsExpr GhcPs)) -> P ([AddAnn],HsBind GhcPs) checkValDef msg _strictness lhs (Just sig) grhss -- x :: ty = rhs parses as a *pattern* binding = checkPatBind msg (cL (combineLocs lhs sig) (ExprWithTySig noExt lhs (mkLHsSigWcType sig))) grhss checkValDef msg strictness lhs Nothing g@(dL->L l (_,grhss)) = do { mb_fun <- isFunLhs lhs ; case mb_fun of Just (fun, is_infix, pats, ann) -> checkFunBind msg strictness ann (getLoc lhs) fun is_infix pats (cL l grhss) Nothing -> checkPatBind msg lhs g } checkFunBind :: SDoc -> SrcStrictness -> [AddAnn] -> SrcSpan -> Located RdrName -> LexicalFixity -> [LHsExpr GhcPs] -> Located (GRHSs GhcPs (LHsExpr GhcPs)) -> P ([AddAnn],HsBind GhcPs) checkFunBind msg strictness ann lhs_loc fun is_infix pats (dL->L rhs_span grhss) = do ps <- checkPatterns msg pats let match_span = combineSrcSpans lhs_loc rhs_span -- Add back the annotations stripped from any HsPar values in the lhs -- mapM_ (\a -> a match_span) ann return (ann, makeFunBind fun [cL match_span (Match { m_ext = noExt , m_ctxt = FunRhs { mc_fun = fun , mc_fixity = is_infix , mc_strictness = strictness } , m_pats = ps , m_grhss = grhss })]) -- The span of the match covers the entire equation. -- That isn't quite right, but it'll do for now. makeFunBind :: Located RdrName -> [LMatch GhcPs (LHsExpr GhcPs)] -> HsBind GhcPs -- Like HsUtils.mkFunBind, but we need to be able to set the fixity too makeFunBind fn ms = FunBind { fun_ext = noExt, fun_id = fn, fun_matches = mkMatchGroup FromSource ms, fun_co_fn = idHsWrapper, fun_tick = [] } checkPatBind :: SDoc -> LHsExpr GhcPs -> Located (a,GRHSs GhcPs (LHsExpr GhcPs)) -> P ([AddAnn],HsBind GhcPs) checkPatBind msg lhs (dL->L _ (_,grhss)) = do { lhs <- checkPattern msg lhs ; return ([],PatBind noExt lhs grhss ([],[])) } checkValSigLhs :: LHsExpr GhcPs -> P (Located RdrName) checkValSigLhs (dL->L _ (HsVar _ lrdr@(dL->L _ v))) | isUnqual v , not (isDataOcc (rdrNameOcc v)) = return lrdr checkValSigLhs lhs@(dL->L l _) = parseErrorSDoc l ((text "Invalid type signature:" <+> ppr lhs <+> text ":: ...") $$ text hint) where hint | foreign_RDR `looks_like` lhs = "Perhaps you meant to use ForeignFunctionInterface?" | default_RDR `looks_like` lhs = "Perhaps you meant to use DefaultSignatures?" | pattern_RDR `looks_like` lhs = "Perhaps you meant to use PatternSynonyms?" | otherwise = "Should be of form :: " -- A common error is to forget the ForeignFunctionInterface flag -- so check for that, and suggest. cf Trac #3805 -- Sadly 'foreign import' still barfs 'parse error' because -- 'import' is a keyword looks_like s (dL->L _ (HsVar _ (dL->L _ v))) = v == s looks_like s (dL->L _ (HsApp _ lhs _)) = looks_like s lhs looks_like _ _ = False foreign_RDR = mkUnqual varName (fsLit "foreign") default_RDR = mkUnqual varName (fsLit "default") pattern_RDR = mkUnqual varName (fsLit "pattern") checkDoAndIfThenElse :: LHsExpr GhcPs -> Bool -> LHsExpr GhcPs -> Bool -> LHsExpr GhcPs -> P () checkDoAndIfThenElse guardExpr semiThen thenExpr semiElse elseExpr | semiThen || semiElse = do doAndIfThenElse <- getBit DoAndIfThenElseBit unless doAndIfThenElse $ do parseErrorSDoc (combineLocs guardExpr elseExpr) (text "Unexpected semi-colons in conditional:" $$ nest 4 expr $$ text "Perhaps you meant to use DoAndIfThenElse?") | otherwise = return () where pprOptSemi True = semi pprOptSemi False = empty expr = text "if" <+> ppr guardExpr <> pprOptSemi semiThen <+> text "then" <+> ppr thenExpr <> pprOptSemi semiElse <+> text "else" <+> ppr elseExpr -- The parser left-associates, so there should -- not be any OpApps inside the e's splitBang :: LHsExpr GhcPs -> Maybe (LHsExpr GhcPs, [LHsExpr GhcPs]) -- Splits (f ! g a b) into (f, [(! g), a, b]) splitBang (dL->L _ (OpApp _ l_arg bang@(dL->L _ (HsVar _ (dL->L _ op))) r_arg)) | op == bang_RDR = Just (l_arg, cL l' (SectionR noExt bang arg1) : argns) where l' = combineLocs bang arg1 (arg1,argns) = split_bang r_arg [] split_bang (dL->L _ (HsApp _ f e)) es = split_bang f (e:es) split_bang e es = (e,es) splitBang _ = Nothing -- See Note [isFunLhs vs mergeDataCon] isFunLhs :: LHsExpr GhcPs -> P (Maybe (Located RdrName, LexicalFixity, [LHsExpr GhcPs],[AddAnn])) -- A variable binding is parsed as a FunBind. -- Just (fun, is_infix, arg_pats) if e is a function LHS -- -- The whole LHS is parsed as a single expression. -- Any infix operators on the LHS will parse left-associatively -- E.g. f !x y !z -- will parse (rather strangely) as -- (f ! x y) ! z -- It's up to isFunLhs to sort out the mess -- -- a .!. !b isFunLhs e = go e [] [] where go (dL->L loc (HsVar _ (dL->L _ f))) es ann | not (isRdrDataCon f) = return (Just (cL loc f, Prefix, es, ann)) go (dL->L _ (HsApp _ f e)) es ann = go f (e:es) ann go (dL->L l (HsPar _ e)) es@(_:_) ann = go e es (ann ++ mkParensApiAnn l) -- Things of the form `!x` are also FunBinds -- See Note [FunBind vs PatBind] go (dL->L _ (SectionR _ (dL->L _ (HsVar _ (dL->L _ bang))) (dL->L l (HsVar _ (L _ var))))) [] ann | bang == bang_RDR , not (isRdrDataCon var) = return (Just (cL l var, Prefix, [], ann)) -- For infix function defns, there should be only one infix *function* -- (though there may be infix *datacons* involved too). So we don't -- need fixity info to figure out which function is being defined. -- a `K1` b `op` c `K2` d -- must parse as -- (a `K1` b) `op` (c `K2` d) -- The renamer checks later that the precedences would yield such a parse. -- -- There is a complication to deal with bang patterns. -- -- ToDo: what about this? -- x + 1 `op` y = ... go e@(L loc (OpApp _ l (dL->L loc' (HsVar _ (dL->L _ op))) r)) es ann | Just (e',es') <- splitBang e = do { bang_on <- getBit BangPatBit ; if bang_on then go e' (es' ++ es) ann else return (Just (cL loc' op, Infix, (l:r:es), ann)) } -- No bangs; behave just like the next case | not (isRdrDataCon op) -- We have found the function! = return (Just (cL loc' op, Infix, (l:r:es), ann)) | otherwise -- Infix data con; keep going = do { mb_l <- go l es ann ; case mb_l of Just (op', Infix, j : k : es', ann') -> return (Just (op', Infix, j : op_app : es', ann')) where op_app = cL loc (OpApp noExt k (cL loc' (HsVar noExt (cL loc' op))) r) _ -> return Nothing } go _ _ _ = return Nothing -- | Either an operator or an operand. data TyEl = TyElOpr RdrName | TyElOpd (HsType GhcPs) | TyElKindApp SrcSpan (LHsType GhcPs) | TyElTilde | TyElBang | TyElUnpackedness ([AddAnn], SourceText, SrcUnpackedness) | TyElDocPrev HsDocString instance Outputable TyEl where ppr (TyElOpr name) = ppr name ppr (TyElOpd ty) = ppr ty ppr (TyElKindApp _ ki) = text "@" <> ppr ki ppr TyElTilde = text "~" ppr TyElBang = text "!" ppr (TyElUnpackedness (_, _, unpk)) = ppr unpk ppr (TyElDocPrev doc) = ppr doc tyElStrictness :: TyEl -> Maybe (AnnKeywordId, SrcStrictness) tyElStrictness TyElTilde = Just (AnnTilde, SrcLazy) tyElStrictness TyElBang = Just (AnnBang, SrcStrict) tyElStrictness _ = Nothing -- | Extract a strictness/unpackedness annotation from the front of a reversed -- 'TyEl' list. pStrictMark :: [Located TyEl] -- reversed TyEl -> Maybe ( Located HsSrcBang {- a strictness/upnackedness marker -} , [AddAnn] , [Located TyEl] {- remaining TyEl -}) pStrictMark ((dL->L l1 x1) : (dL->L l2 x2) : xs) | Just (strAnnId, str) <- tyElStrictness x1 , TyElUnpackedness (unpkAnns, prag, unpk) <- x2 = Just ( cL (combineSrcSpans l1 l2) (HsSrcBang prag unpk str) , unpkAnns ++ [\s -> addAnnotation s strAnnId l1] , xs ) pStrictMark ((dL->L l x1) : xs) | Just (strAnnId, str) <- tyElStrictness x1 = Just ( cL l (HsSrcBang NoSourceText NoSrcUnpack str) , [\s -> addAnnotation s strAnnId l] , xs ) pStrictMark ((dL->L l x1) : xs) | TyElUnpackedness (anns, prag, unpk) <- x1 = Just ( cL l (HsSrcBang prag unpk NoSrcStrict) , anns , xs ) pStrictMark _ = Nothing pBangTy :: LHsType GhcPs -- a type to be wrapped inside HsBangTy -> [Located TyEl] -- reversed TyEl -> ( Bool {- has a strict mark been consumed? -} , LHsType GhcPs {- the resulting BangTy -} , P () {- add annotations -} , [Located TyEl] {- remaining TyEl -}) pBangTy lt@(dL->L l1 _) xs = case pStrictMark xs of Nothing -> (False, lt, pure (), xs) Just (dL->L l2 strictMark, anns, xs') -> let bl = combineSrcSpans l1 l2 bt = HsBangTy noExt strictMark lt in (True, cL bl bt, addAnnsAt bl anns, xs') -- | Merge a /reversed/ and /non-empty/ soup of operators and operands -- into a type. -- -- User input: @F x y + G a b * X@ -- Input to 'mergeOps': [X, *, b, a, G, +, y, x, F] -- Output corresponds to what the user wrote assuming all operators are of the -- same fixity and right-associative. -- -- It's a bit silly that we're doing it at all, as the renamer will have to -- rearrange this, and it'd be easier to keep things separate. -- -- See Note [Parsing data constructors is hard] mergeOps :: [Located TyEl] -> P (LHsType GhcPs) mergeOps ((dL->L l1 (TyElOpd t)) : xs) | (_, t', addAnns, xs') <- pBangTy (cL l1 t) xs , null xs' -- We accept a BangTy only when there are no preceding TyEl. = addAnns >> return t' mergeOps all_xs = go (0 :: Int) [] id all_xs where -- NB. When modifying clauses in 'go', make sure that the reasoning in -- Note [Non-empty 'acc' in mergeOps clause [end]] is still correct. -- clause [unpk]: -- handle (NO)UNPACK pragmas go k acc ops_acc ((dL->L l (TyElUnpackedness (anns, unpkSrc, unpk))):xs) = if not (null acc) && null xs then do { (addAccAnns, acc') <- eitherToP $ mergeOpsAcc acc ; let a = ops_acc acc' strictMark = HsSrcBang unpkSrc unpk NoSrcStrict bl = combineSrcSpans l (getLoc a) bt = HsBangTy noExt strictMark a ; addAccAnns ; addAnnsAt bl anns ; return (cL bl bt) } else parseErrorSDoc l unpkError where unpkSDoc = case unpkSrc of NoSourceText -> ppr unpk SourceText str -> text str <> text " #-}" unpkError | not (null xs) = unpkSDoc <+> text "cannot appear inside a type." | null acc && k == 0 = unpkSDoc <+> text "must be applied to a type." | otherwise = -- See Note [Impossible case in mergeOps clause [unpk]] panic "mergeOps.UNPACK: impossible position" -- clause [doc]: -- we do not expect to encounter any docs go _ _ _ ((dL->L l (TyElDocPrev _)):_) = failOpDocPrev l -- to improve error messages, we do a bit of guesswork to determine if the -- user intended a '!' or a '~' as a strictness annotation go k acc ops_acc ((dL->L l x) : xs) | Just (_, str) <- tyElStrictness x , let guess [] = True guess ((dL->L _ (TyElOpd _)):_) = False guess ((dL->L _ (TyElOpr _)):_) = True guess ((dL->L _ (TyElKindApp _ _)):_) = False guess ((dL->L _ (TyElTilde)):_) = True guess ((dL->L _ (TyElBang)):_) = True guess ((dL->L _ (TyElUnpackedness _)):_) = True guess ((dL->L _ (TyElDocPrev _)):xs') = guess xs' guess _ = panic "mergeOps.go.guess: Impossible Match" -- due to #15884 in guess xs = if not (null acc) && (k > 1 || length acc > 1) then do { (_, a) <- eitherToP (mergeOpsAcc acc) -- no need to add annotations since it fails anyways! ; failOpStrictnessCompound (cL l str) (ops_acc a) } else failOpStrictnessPosition (cL l str) -- clause [opr]: -- when we encounter an operator, we must have accumulated -- something for its rhs, and there must be something left -- to build its lhs. go k acc ops_acc ((dL->L l (TyElOpr op)):xs) = if null acc || null (filter isTyElOpd xs) then failOpFewArgs (cL l op) else do { (addAccAnns, acc') <- eitherToP (mergeOpsAcc acc) ; addAccAnns ; go (k + 1) [] (\c -> mkLHsOpTy c (cL l op) (ops_acc acc')) xs } where isTyElOpd (dL->L _ (TyElOpd _)) = True isTyElOpd _ = False -- clause [opr.1]: interpret 'TyElTilde' as an operator go k acc ops_acc ((dL->L l TyElTilde):xs) = let op = eqTyCon_RDR in go k acc ops_acc (cL l (TyElOpr op):xs) -- clause [opr.2]: interpret 'TyElBang' as an operator go k acc ops_acc ((dL->L l TyElBang):xs) = let op = mkUnqual tcClsName (fsLit "!") in go k acc ops_acc (cL l (TyElOpr op):xs) -- clause [opd]: -- whenever an operand is encountered, it is added to the accumulator go k acc ops_acc ((dL->L l (TyElOpd a)):xs) = go k (HsValArg (cL l a):acc) ops_acc xs -- clause [tyapp]: -- whenever a type application is encountered, it is added to the accumulator go k acc ops_acc ((dL->L _ (TyElKindApp l a)):xs) = go k (HsTypeArg (l, a):acc) ops_acc xs -- clause [end] -- See Note [Non-empty 'acc' in mergeOps clause [end]] go _ acc ops_acc [] = do { (addAccAnns, acc') <- eitherToP (mergeOpsAcc acc) ; addAccAnns ; return (ops_acc acc') } go _ _ _ _ = panic "mergeOps.go: Impossible Match" -- due to #15884 mergeOpsAcc :: [HsArg (LHsType GhcPs) (SrcSpan, LHsKind GhcPs)] -> Either (SrcSpan, SDoc) (P (), LHsType GhcPs) mergeOpsAcc [] = panic "mergeOpsAcc: empty input" mergeOpsAcc (HsTypeArg (_, L loc ki):_) = Left (loc, text "Unexpected type application:" <+> ppr ki) mergeOpsAcc (HsValArg ty : xs) = go1 (pure ()) ty xs where go1 :: P () -> LHsType GhcPs -> [HsArg (LHsType GhcPs) (SrcSpan, LHsKind GhcPs)] -> Either (SrcSpan, SDoc) (P (), LHsType GhcPs) go1 anns lhs [] = Right (anns, lhs) go1 anns lhs (x:xs) = case x of HsValArg ty -> go1 anns (mkHsAppTy lhs ty) xs HsTypeArg (loc, ki) -> let ty = mkHsAppKindTy lhs ki in go1 (addAnnotation (getLoc ty) AnnAt loc >> anns) ty xs HsArgPar _ -> go1 anns lhs xs mergeOpsAcc (HsArgPar _: xs) = mergeOpsAcc xs {- Note [Impossible case in mergeOps clause [unpk]] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This case should never occur. Let us consider all possible variations of 'acc', 'xs', and 'k': acc xs k ============================== null | null 0 -- "must be applied to a type" null | not null 0 -- "must be applied to a type" not null | null 0 -- successful parse not null | not null 0 -- "cannot appear inside a type" null | null >0 -- handled in clause [opr] null | not null >0 -- "cannot appear inside a type" not null | null >0 -- successful parse not null | not null >0 -- "cannot appear inside a type" The (null acc && null xs && k>0) case is handled in clause [opr] by the following check: if ... || null (filter isTyElOpd xs) then failOpFewArgs (L l op) We know that this check has been performed because k>0, and by the time we reach the end of the list (null xs), the only way for (null acc) to hold is that there was not a single TyElOpd between the operator and the end of the list. But this case is caught by the check and reported as 'failOpFewArgs'. -} {- Note [Non-empty 'acc' in mergeOps clause [end]] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In clause [end] we need to know that 'acc' is non-empty to call 'mergeAcc' without a check. Running 'mergeOps' with an empty input list is forbidden, so we do not consider this possibility. This means we'll hit at least one other clause before we reach clause [end]. * Clauses [unpk] and [doc] do not call 'go' recursively, so we cannot hit clause [end] from there. * Clause [opd] makes 'acc' non-empty, so if we hit clause [end] after it, 'acc' will be non-empty. * Clause [opr] checks that (filter isTyElOpd xs) is not null - so we are going to hit clause [opd] at least once before we reach clause [end], making 'acc' non-empty. * There are no other clauses. Therefore, it is safe to omit a check for non-emptiness of 'acc' in clause [end]. -} pInfixSide :: [Located TyEl] -> Maybe (LHsType GhcPs, P (), [Located TyEl]) pInfixSide ((dL->L l (TyElOpd t)):xs) | (True, t', addAnns, xs') <- pBangTy (cL l t) xs = Just (t', addAnns, xs') pInfixSide (el:xs1) | Just t1 <- pLHsTypeArg el = go [t1] xs1 where go :: [HsArg (LHsType GhcPs) (SrcSpan, LHsKind GhcPs)] -> [Located TyEl] -> Maybe (LHsType GhcPs, P (), [Located TyEl]) go acc (el:xs) | Just t <- pLHsTypeArg el = go (t:acc) xs go acc xs = case mergeOpsAcc acc of Left _ -> Nothing Right (addAnns, acc') -> Just (acc', addAnns, xs) pInfixSide _ = Nothing pLHsTypeArg :: Located TyEl -> Maybe (HsArg (LHsType GhcPs) (SrcSpan, LHsKind GhcPs)) pLHsTypeArg (dL->L l (TyElOpd a)) = Just (HsValArg (L l a)) pLHsTypeArg (dL->L _ (TyElKindApp l a)) = Just (HsTypeArg (l,a)) pLHsTypeArg _ = Nothing pDocPrev :: [Located TyEl] -> (Maybe LHsDocString, [Located TyEl]) pDocPrev = go Nothing where go mTrailingDoc ((dL->L l (TyElDocPrev doc)):xs) = go (mTrailingDoc `mplus` Just (cL l doc)) xs go mTrailingDoc xs = (mTrailingDoc, xs) orErr :: Maybe a -> b -> Either b a orErr (Just a) _ = Right a orErr Nothing b = Left b {- Note [isFunLhs vs mergeDataCon] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When parsing a function LHS, we do not know whether to treat (!) as a strictness annotation or an infix operator: f ! a = ... Without -XBangPatterns, this parses as (!) f a = ... with -XBangPatterns, this parses as f (!a) = ... So in function declarations we opted to always parse as if -XBangPatterns were off, and then rejig in 'isFunLhs'. There are two downsides to this approach: 1. It is not particularly elegant, as there's a point in our pipeline where the representation is awfully incorrect. For instance, f !a b !c = ... will be first parsed as (f ! a b) ! c = ... 2. There are cases that it fails to cover, for instance infix declarations: !a + !b = ... will trigger an error. Unfortunately, we cannot define different productions in the 'happy' grammar depending on whether -XBangPatterns are enabled. When parsing data constructors, we face a similar issue: (a) data T1 = C ! D (b) data T2 = C ! D => ... In (a) the first bang is a strictness annotation, but in (b) it is a type operator. A 'happy'-based parser does not have unlimited lookahead to check for =>, so we must first parse (C ! D) into a common representation. If we tried to mirror the approach used in functions, we would parse both sides of => as types, and then rejig. However, we take a different route and use an intermediate data structure, a reversed list of 'TyEl'. See Note [Parsing data constructors is hard] for details. This approach does not suffer from the issues of 'isFunLhs': 1. A sequence of 'TyEl' is a dedicated intermediate representation, not an incorrectly parsed type. Therefore, we do not have confusing states in our pipeline. (Except for representing data constructors as type variables). 2. We can handle infix data constructors with strictness annotations: data T a b = !a :+ !b -} -- | Merge a /reversed/ and /non-empty/ soup of operators and operands -- into a data constructor. -- -- User input: @C !A B -- ^ doc@ -- Input to 'mergeDataCon': ["doc", B, !, A, C] -- Output: (C, PrefixCon [!A, B], "doc") -- -- See Note [Parsing data constructors is hard] -- See Note [isFunLhs vs mergeDataCon] mergeDataCon :: [Located TyEl] -> P ( Located RdrName -- constructor name , HsConDeclDetails GhcPs -- constructor field information , Maybe LHsDocString -- docstring to go on the constructor ) mergeDataCon all_xs = do { (addAnns, a) <- eitherToP res ; addAnns ; return a } where -- We start by splitting off the trailing documentation comment, -- if any exists. (mTrailingDoc, all_xs') = pDocPrev all_xs -- Determine whether the trailing documentation comment exists and is the -- only docstring in this constructor declaration. -- -- When true, it means that it applies to the constructor itself: -- data T = C -- A -- B -- ^ Comment on C (singleDoc == True) -- -- When false, it means that it applies to the last field: -- data T = C -- ^ Comment on C -- A -- ^ Comment on A -- B -- ^ Comment on B (singleDoc == False) singleDoc = isJust mTrailingDoc && null [ () | (dL->L _ (TyElDocPrev _)) <- all_xs' ] -- The result of merging the list of reversed TyEl into a -- data constructor, along with [AddAnn]. res = goFirst all_xs' -- Take the trailing docstring into account when interpreting -- the docstring near the constructor. -- -- data T = C -- ^ docstring right after C -- A -- B -- ^ trailing docstring -- -- 'mkConDoc' must be applied to the docstring right after C, so that it -- falls back to the trailing docstring when appropriate (see singleDoc). mkConDoc mDoc | singleDoc = mDoc `mplus` mTrailingDoc | otherwise = mDoc -- The docstring for the last field of a data constructor. trailingFieldDoc | singleDoc = Nothing | otherwise = mTrailingDoc goFirst [ dL->L l (TyElOpd (HsTyVar _ _ (dL->L _ tc))) ] = do { data_con <- tyConToDataCon l tc ; return (pure (), (data_con, PrefixCon [], mTrailingDoc)) } goFirst ((dL->L l (TyElOpd (HsRecTy _ fields))):xs) | (mConDoc, xs') <- pDocPrev xs , [ dL->L l' (TyElOpd (HsTyVar _ _ (dL->L _ tc))) ] <- xs' = do { data_con <- tyConToDataCon l' tc ; let mDoc = mTrailingDoc `mplus` mConDoc ; return (pure (), (data_con, RecCon (cL l fields), mDoc)) } goFirst [dL->L l (TyElOpd (HsTupleTy _ HsBoxedOrConstraintTuple ts))] = return ( pure () , ( cL l (getRdrName (tupleDataCon Boxed (length ts))) , PrefixCon ts , mTrailingDoc ) ) goFirst ((dL->L l (TyElOpd t)):xs) | (_, t', addAnns, xs') <- pBangTy (cL l t) xs = go addAnns Nothing [mkLHsDocTyMaybe t' trailingFieldDoc] xs' goFirst (L l (TyElKindApp _ _):_) = goInfix Monoid.<> Left (l, kindAppErr) goFirst xs = go (pure ()) mTrailingDoc [] xs go addAnns mLastDoc ts [ dL->L l (TyElOpd (HsTyVar _ _ (dL->L _ tc))) ] = do { data_con <- tyConToDataCon l tc ; return (addAnns, (data_con, PrefixCon ts, mkConDoc mLastDoc)) } go addAnns mLastDoc ts ((dL->L l (TyElDocPrev doc)):xs) = go addAnns (mLastDoc `mplus` Just (cL l doc)) ts xs go addAnns mLastDoc ts ((dL->L l (TyElOpd t)):xs) | (_, t', addAnns', xs') <- pBangTy (cL l t) xs , t'' <- mkLHsDocTyMaybe t' mLastDoc = go (addAnns >> addAnns') Nothing (t'':ts) xs' go _ _ _ ((dL->L _ (TyElOpr _)):_) = -- Encountered an operator: backtrack to the beginning and attempt -- to parse as an infix definition. goInfix go _ _ _ (L l (TyElKindApp _ _):_) = goInfix Monoid.<> Left (l, kindAppErr) go _ _ _ _ = Left malformedErr where malformedErr = ( foldr combineSrcSpans noSrcSpan (map getLoc all_xs') , text "Cannot parse data constructor" <+> text "in a data/newtype declaration:" $$ nest 2 (hsep . reverse $ map ppr all_xs')) goInfix = do { let xs0 = all_xs' ; (rhs_t, rhs_addAnns, xs1) <- pInfixSide xs0 `orErr` malformedErr ; let (mOpDoc, xs2) = pDocPrev xs1 ; (op, xs3) <- case xs2 of (dL->L l (TyElOpr op)) : xs3 -> do { data_con <- tyConToDataCon l op ; return (data_con, xs3) } _ -> Left malformedErr ; let (mLhsDoc, xs4) = pDocPrev xs3 ; (lhs_t, lhs_addAnns, xs5) <- pInfixSide xs4 `orErr` malformedErr ; unless (null xs5) (Left malformedErr) ; let rhs = mkLHsDocTyMaybe rhs_t trailingFieldDoc lhs = mkLHsDocTyMaybe lhs_t mLhsDoc addAnns = lhs_addAnns >> rhs_addAnns ; return (addAnns, (op, InfixCon lhs rhs, mkConDoc mOpDoc)) } where malformedErr = ( foldr combineSrcSpans noSrcSpan (map getLoc all_xs') , text "Cannot parse an infix data constructor" <+> text "in a data/newtype declaration:" $$ nest 2 (hsep . reverse $ map ppr all_xs')) kindAppErr = text "Unexpected kind application" <+> text "in a data/newtype declaration:" $$ nest 2 (hsep . reverse $ map ppr all_xs') --------------------------------------------------------------------------- -- | Check for monad comprehensions -- -- If the flag MonadComprehensions is set, return a 'MonadComp' context, -- otherwise use the usual 'ListComp' context checkMonadComp :: P (HsStmtContext Name) checkMonadComp = do monadComprehensions <- getBit MonadComprehensionsBit return $ if monadComprehensions then MonadComp else ListComp -- ------------------------------------------------------------------------- -- Checking arrow syntax. -- We parse arrow syntax as expressions and check for valid syntax below, -- converting the expression into a pattern at the same time. checkCommand :: LHsExpr GhcPs -> P (LHsCmd GhcPs) checkCommand lc = locMap checkCmd lc locMap :: (SrcSpan -> a -> P b) -> Located a -> P (Located b) locMap f (dL->L l a) = f l a >>= (\b -> return $ cL l b) checkCmd :: SrcSpan -> HsExpr GhcPs -> P (HsCmd GhcPs) checkCmd _ (HsArrApp _ e1 e2 haat b) = return $ HsCmdArrApp noExt e1 e2 haat b checkCmd _ (HsArrForm _ e mf args) = return $ HsCmdArrForm noExt e Prefix mf args checkCmd _ (HsApp _ e1 e2) = checkCommand e1 >>= (\c -> return $ HsCmdApp noExt c e2) checkCmd _ (HsLam _ mg) = checkCmdMatchGroup mg >>= (\mg' -> return $ HsCmdLam noExt mg') checkCmd _ (HsPar _ e) = checkCommand e >>= (\c -> return $ HsCmdPar noExt c) checkCmd _ (HsCase _ e mg) = checkCmdMatchGroup mg >>= (\mg' -> return $ HsCmdCase noExt e mg') checkCmd _ (HsIf _ cf ep et ee) = do pt <- checkCommand et pe <- checkCommand ee return $ HsCmdIf noExt cf ep pt pe checkCmd _ (HsLet _ lb e) = checkCommand e >>= (\c -> return $ HsCmdLet noExt lb c) checkCmd _ (HsDo _ DoExpr (dL->L l stmts)) = mapM checkCmdLStmt stmts >>= (\ss -> return $ HsCmdDo noExt (cL l ss) ) checkCmd _ (OpApp _ eLeft op eRight) = do -- OpApp becomes a HsCmdArrForm with a (Just fixity) in it c1 <- checkCommand eLeft c2 <- checkCommand eRight let arg1 = cL (getLoc c1) $ HsCmdTop noExt c1 arg2 = cL (getLoc c2) $ HsCmdTop noExt c2 return $ HsCmdArrForm noExt op Infix Nothing [arg1, arg2] checkCmd l e = cmdFail l e checkCmdLStmt :: ExprLStmt GhcPs -> P (CmdLStmt GhcPs) checkCmdLStmt = locMap checkCmdStmt checkCmdStmt :: SrcSpan -> ExprStmt GhcPs -> P (CmdStmt GhcPs) checkCmdStmt _ (LastStmt x e s r) = checkCommand e >>= (\c -> return $ LastStmt x c s r) checkCmdStmt _ (BindStmt x pat e b f) = checkCommand e >>= (\c -> return $ BindStmt x pat c b f) checkCmdStmt _ (BodyStmt x e t g) = checkCommand e >>= (\c -> return $ BodyStmt x c t g) checkCmdStmt _ (LetStmt x bnds) = return $ LetStmt x bnds checkCmdStmt _ stmt@(RecStmt { recS_stmts = stmts }) = do ss <- mapM checkCmdLStmt stmts return $ stmt { recS_ext = noExt, recS_stmts = ss } checkCmdStmt _ (XStmtLR _) = panic "checkCmdStmt" checkCmdStmt l stmt = cmdStmtFail l stmt checkCmdMatchGroup :: MatchGroup GhcPs (LHsExpr GhcPs) -> P (MatchGroup GhcPs (LHsCmd GhcPs)) checkCmdMatchGroup mg@(MG { mg_alts = (dL->L l ms) }) = do ms' <- mapM (locMap $ const convert) ms return $ mg { mg_ext = noExt , mg_alts = cL l ms' } where convert match@(Match { m_grhss = grhss }) = do grhss' <- checkCmdGRHSs grhss return $ match { m_ext = noExt, m_grhss = grhss'} convert (XMatch _) = panic "checkCmdMatchGroup.XMatch" checkCmdMatchGroup (XMatchGroup {}) = panic "checkCmdMatchGroup" checkCmdGRHSs :: GRHSs GhcPs (LHsExpr GhcPs) -> P (GRHSs GhcPs (LHsCmd GhcPs)) checkCmdGRHSs (GRHSs x grhss binds) = do grhss' <- mapM checkCmdGRHS grhss return $ GRHSs x grhss' binds checkCmdGRHSs (XGRHSs _) = panic "checkCmdGRHSs" checkCmdGRHS :: LGRHS GhcPs (LHsExpr GhcPs) -> P (LGRHS GhcPs (LHsCmd GhcPs)) checkCmdGRHS = locMap $ const convert where convert (GRHS x stmts e) = do c <- checkCommand e -- cmdStmts <- mapM checkCmdLStmt stmts return $ GRHS x {- cmdStmts -} stmts c convert (XGRHS _) = panic "checkCmdGRHS" cmdFail :: SrcSpan -> HsExpr GhcPs -> P a cmdFail loc e = parseErrorSDoc loc (text "Parse error in command:" <+> ppr e) cmdStmtFail :: SrcSpan -> Stmt GhcPs (LHsExpr GhcPs) -> P a cmdStmtFail loc e = parseErrorSDoc loc (text "Parse error in command statement:" <+> ppr e) --------------------------------------------------------------------------- -- Miscellaneous utilities -- | Check if a fixity is valid. We support bypassing the usual bound checks -- for some special operators. checkPrecP :: Located (SourceText,Int) -- ^ precedence -> Located (OrdList (Located RdrName)) -- ^ operators -> P () checkPrecP (dL->L l (_,i)) (dL->L _ ol) | 0 <= i, i <= maxPrecedence = pure () | all specialOp ol = pure () | otherwise = parseErrorSDoc l (text ("Precedence out of range: " ++ show i)) where specialOp op = unLoc op `elem` [ eqTyCon_RDR , getRdrName funTyCon ] mkRecConstrOrUpdate :: LHsExpr GhcPs -> SrcSpan -> ([LHsRecField GhcPs (LHsExpr GhcPs)], Bool) -> P (HsExpr GhcPs) mkRecConstrOrUpdate (dL->L l (HsVar _ (dL->L _ c))) _ (fs,dd) | isRdrDataCon c = return (mkRdrRecordCon (cL l c) (mk_rec_fields fs dd)) mkRecConstrOrUpdate exp@(dL->L l _) _ (fs,dd) | dd = parseErrorSDoc l (text "You cannot use `..' in a record update") | otherwise = return (mkRdrRecordUpd exp (map (fmap mk_rec_upd_field) fs)) mkRdrRecordUpd :: LHsExpr GhcPs -> [LHsRecUpdField GhcPs] -> HsExpr GhcPs mkRdrRecordUpd exp flds = RecordUpd { rupd_ext = noExt , rupd_expr = exp , rupd_flds = flds } mkRdrRecordCon :: Located RdrName -> HsRecordBinds GhcPs -> HsExpr GhcPs mkRdrRecordCon con flds = RecordCon { rcon_ext = noExt, rcon_con_name = con, rcon_flds = flds } mk_rec_fields :: [LHsRecField id arg] -> Bool -> HsRecFields id arg mk_rec_fields fs False = HsRecFields { rec_flds = fs, rec_dotdot = Nothing } mk_rec_fields fs True = HsRecFields { rec_flds = fs , rec_dotdot = Just (length fs) } mk_rec_upd_field :: HsRecField GhcPs (LHsExpr GhcPs) -> HsRecUpdField GhcPs mk_rec_upd_field (HsRecField (dL->L loc (FieldOcc _ rdr)) arg pun) = HsRecField (L loc (Unambiguous noExt rdr)) arg pun mk_rec_upd_field (HsRecField (dL->L _ (XFieldOcc _)) _ _) = panic "mk_rec_upd_field" mk_rec_upd_field (HsRecField _ _ _) = panic "mk_rec_upd_field: Impossible Match" -- due to #15884 mkInlinePragma :: SourceText -> (InlineSpec, RuleMatchInfo) -> Maybe Activation -> InlinePragma -- The (Maybe Activation) is because the user can omit -- the activation spec (and usually does) mkInlinePragma src (inl, match_info) mb_act = InlinePragma { inl_src = src -- Note [Pragma source text] in BasicTypes , inl_inline = inl , inl_sat = Nothing , inl_act = act , inl_rule = match_info } where act = case mb_act of Just act -> act Nothing -> -- No phase specified case inl of NoInline -> NeverActive _other -> AlwaysActive ----------------------------------------------------------------------------- -- utilities for foreign declarations -- construct a foreign import declaration -- mkImport :: Located CCallConv -> Located Safety -> (Located StringLiteral, Located RdrName, LHsSigType GhcPs) -> P (HsDecl GhcPs) mkImport cconv safety (L loc (StringLiteral esrc entity), v, ty) = case unLoc cconv of CCallConv -> mkCImport CApiConv -> mkCImport StdCallConv -> mkCImport PrimCallConv -> mkOtherImport JavaScriptCallConv -> mkOtherImport where -- Parse a C-like entity string of the following form: -- "[static] [chname] [&] [cid]" | "dynamic" | "wrapper" -- If 'cid' is missing, the function name 'v' is used instead as symbol -- name (cf section 8.5.1 in Haskell 2010 report). mkCImport = do let e = unpackFS entity case parseCImport cconv safety (mkExtName (unLoc v)) e (cL loc esrc) of Nothing -> parseErrorSDoc loc (text "Malformed entity string") Just importSpec -> returnSpec importSpec -- currently, all the other import conventions only support a symbol name in -- the entity string. If it is missing, we use the function name instead. mkOtherImport = returnSpec importSpec where entity' = if nullFS entity then mkExtName (unLoc v) else entity funcTarget = CFunction (StaticTarget esrc entity' Nothing True) importSpec = CImport cconv safety Nothing funcTarget (cL loc esrc) returnSpec spec = return $ ForD noExt $ ForeignImport { fd_i_ext = noExt , fd_name = v , fd_sig_ty = ty , fd_fi = spec } -- the string "foo" is ambiguous: either a header or a C identifier. The -- C identifier case comes first in the alternatives below, so we pick -- that one. parseCImport :: Located CCallConv -> Located Safety -> FastString -> String -> Located SourceText -> Maybe ForeignImport parseCImport cconv safety nm str sourceText = listToMaybe $ map fst $ filter (null.snd) $ readP_to_S parse str where parse = do skipSpaces r <- choice [ string "dynamic" >> return (mk Nothing (CFunction DynamicTarget)), string "wrapper" >> return (mk Nothing CWrapper), do optional (token "static" >> skipSpaces) ((mk Nothing <$> cimp nm) +++ (do h <- munch1 hdr_char skipSpaces mk (Just (Header (SourceText h) (mkFastString h))) <$> cimp nm)) ] skipSpaces return r token str = do _ <- string str toks <- look case toks of c : _ | id_char c -> pfail _ -> return () mk h n = CImport cconv safety h n sourceText hdr_char c = not (isSpace c) -- header files are filenames, which can contain -- pretty much any char (depending on the platform), -- so just accept any non-space character id_first_char c = isAlpha c || c == '_' id_char c = isAlphaNum c || c == '_' cimp nm = (ReadP.char '&' >> skipSpaces >> CLabel <$> cid) +++ (do isFun <- case unLoc cconv of CApiConv -> option True (do token "value" skipSpaces return False) _ -> return True cid' <- cid return (CFunction (StaticTarget NoSourceText cid' Nothing isFun))) where cid = return nm +++ (do c <- satisfy id_first_char cs <- many (satisfy id_char) return (mkFastString (c:cs))) -- construct a foreign export declaration -- mkExport :: Located CCallConv -> (Located StringLiteral, Located RdrName, LHsSigType GhcPs) -> P (HsDecl GhcPs) mkExport (dL->L lc cconv) (dL->L le (StringLiteral esrc entity), v, ty) = return $ ForD noExt $ ForeignExport { fd_e_ext = noExt, fd_name = v, fd_sig_ty = ty , fd_fe = CExport (cL lc (CExportStatic esrc entity' cconv)) (cL le esrc) } where entity' | nullFS entity = mkExtName (unLoc v) | otherwise = entity -- Supplying the ext_name in a foreign decl is optional; if it -- isn't there, the Haskell name is assumed. Note that no transformation -- of the Haskell name is then performed, so if you foreign export (++), -- it's external name will be "++". Too bad; it's important because we don't -- want z-encoding (e.g. names with z's in them shouldn't be doubled) -- mkExtName :: RdrName -> CLabelString mkExtName rdrNm = mkFastString (occNameString (rdrNameOcc rdrNm)) -------------------------------------------------------------------------------- -- Help with module system imports/exports data ImpExpSubSpec = ImpExpAbs | ImpExpAll | ImpExpList [Located ImpExpQcSpec] | ImpExpAllWith [Located ImpExpQcSpec] data ImpExpQcSpec = ImpExpQcName (Located RdrName) | ImpExpQcType (Located RdrName) | ImpExpQcWildcard mkModuleImpExp :: Located ImpExpQcSpec -> ImpExpSubSpec -> P (IE GhcPs) mkModuleImpExp (dL->L l specname) subs = case subs of ImpExpAbs | isVarNameSpace (rdrNameSpace name) -> return $ IEVar noExt (cL l (ieNameFromSpec specname)) | otherwise -> IEThingAbs noExt . cL l <$> nameT ImpExpAll -> IEThingAll noExt . cL l <$> nameT ImpExpList xs -> (\newName -> IEThingWith noExt (cL l newName) NoIEWildcard (wrapped xs) []) <$> nameT ImpExpAllWith xs -> do allowed <- getBit PatternSynonymsBit if allowed then let withs = map unLoc xs pos = maybe NoIEWildcard IEWildcard (findIndex isImpExpQcWildcard withs) ies = wrapped $ filter (not . isImpExpQcWildcard . unLoc) xs in (\newName -> IEThingWith noExt (cL l newName) pos ies []) <$> nameT else parseErrorSDoc l (text "Illegal export form (use PatternSynonyms to enable)") where name = ieNameVal specname nameT = if isVarNameSpace (rdrNameSpace name) then parseErrorSDoc l (text "Expecting a type constructor but found a variable," <+> quotes (ppr name) <> text "." $$ if isSymOcc $ rdrNameOcc name then text "If" <+> quotes (ppr name) <+> text "is a type constructor" <+> text "then enable ExplicitNamespaces and use the 'type' keyword." else empty) else return $ ieNameFromSpec specname ieNameVal (ImpExpQcName ln) = unLoc ln ieNameVal (ImpExpQcType ln) = unLoc ln ieNameVal (ImpExpQcWildcard) = panic "ieNameVal got wildcard" ieNameFromSpec (ImpExpQcName ln) = IEName ln ieNameFromSpec (ImpExpQcType ln) = IEType ln ieNameFromSpec (ImpExpQcWildcard) = panic "ieName got wildcard" wrapped = map (onHasSrcSpan ieNameFromSpec) mkTypeImpExp :: Located RdrName -- TcCls or Var name space -> P (Located RdrName) mkTypeImpExp name = do allowed <- getBit ExplicitNamespacesBit if allowed then return (fmap (`setRdrNameSpace` tcClsName) name) else parseErrorSDoc (getLoc name) (text "Illegal keyword 'type' (use ExplicitNamespaces to enable)") checkImportSpec :: Located [LIE GhcPs] -> P (Located [LIE GhcPs]) checkImportSpec ie@(dL->L _ specs) = case [l | (dL->L l (IEThingWith _ _ (IEWildcard _) _ _)) <- specs] of [] -> return ie (l:_) -> importSpecError l where importSpecError l = parseErrorSDoc l (text "Illegal import form, this syntax can only be used to bundle" $+$ text "pattern synonyms with types in module exports.") -- In the correct order mkImpExpSubSpec :: [Located ImpExpQcSpec] -> P ([AddAnn], ImpExpSubSpec) mkImpExpSubSpec [] = return ([], ImpExpList []) mkImpExpSubSpec [dL->L _ ImpExpQcWildcard] = return ([], ImpExpAll) mkImpExpSubSpec xs = if (any (isImpExpQcWildcard . unLoc) xs) then return $ ([], ImpExpAllWith xs) else return $ ([], ImpExpList xs) isImpExpQcWildcard :: ImpExpQcSpec -> Bool isImpExpQcWildcard ImpExpQcWildcard = True isImpExpQcWildcard _ = False ----------------------------------------------------------------------------- -- Warnings and failures warnStarIsType :: SrcSpan -> P () warnStarIsType span = addWarning Opt_WarnStarIsType span msg where msg = text "Using" <+> quotes (text "*") <+> text "(or its Unicode variant) to mean" <+> quotes (text "Data.Kind.Type") $$ text "relies on the StarIsType extension, which will become" $$ text "deprecated in the future." $$ text "Suggested fix: use" <+> quotes (text "Type") <+> text "from" <+> quotes (text "Data.Kind") <+> text "instead." warnStarBndr :: SrcSpan -> P () warnStarBndr span = addWarning Opt_WarnStarBinder span msg where msg = text "Found binding occurrence of" <+> quotes (text "*") <+> text "yet StarIsType is enabled." $$ text "NB. To use (or export) this operator in" <+> text "modules with StarIsType," $$ text " including the definition module, you must qualify it." failOpFewArgs :: Located RdrName -> P a failOpFewArgs (dL->L loc op) = do { star_is_type <- getBit StarIsTypeBit ; let msg = too_few $$ starInfo star_is_type op ; parseErrorSDoc loc msg } where too_few = text "Operator applied to too few arguments:" <+> ppr op failOpDocPrev :: SrcSpan -> P a failOpDocPrev loc = parseErrorSDoc loc msg where msg = text "Unexpected documentation comment." failOpStrictnessCompound :: Located SrcStrictness -> LHsType GhcPs -> P a failOpStrictnessCompound (dL->L _ str) (dL->L loc ty) = parseErrorSDoc loc msg where msg = text "Strictness annotation applied to a compound type." $$ text "Did you mean to add parentheses?" $$ nest 2 (ppr str <> parens (ppr ty)) failOpStrictnessPosition :: Located SrcStrictness -> P a failOpStrictnessPosition (dL->L loc _) = parseErrorSDoc loc msg where msg = text "Strictness annotation cannot appear in this position." ----------------------------------------------------------------------------- -- Misc utils parseErrorSDoc :: SrcSpan -> SDoc -> P a parseErrorSDoc span s = failSpanMsgP span s -- | Hint about bang patterns, assuming @BangPatterns@ is off. hintBangPat :: SrcSpan -> HsExpr GhcPs -> P () hintBangPat span e = do bang_on <- getBit BangPatBit unless bang_on $ parseErrorSDoc span (text "Illegal bang-pattern (use BangPatterns):" $$ ppr e) data SumOrTuple = Sum ConTag Arity (LHsExpr GhcPs) | Tuple [LHsTupArg GhcPs] mkSumOrTuple :: Boxity -> SrcSpan -> SumOrTuple -> P (HsExpr GhcPs) -- Tuple mkSumOrTuple boxity _ (Tuple es) = return (ExplicitTuple noExt es boxity) -- Sum mkSumOrTuple Unboxed _ (Sum alt arity e) = return (ExplicitSum noExt alt arity e) mkSumOrTuple Boxed l (Sum alt arity (dL->L _ e)) = parseErrorSDoc l (hang (text "Boxed sums not supported:") 2 (ppr_boxed_sum alt arity e)) where ppr_boxed_sum :: ConTag -> Arity -> HsExpr GhcPs -> SDoc ppr_boxed_sum alt arity e = text "(" <+> ppr_bars (alt - 1) <+> ppr e <+> ppr_bars (arity - alt) <+> text ")" ppr_bars n = hsep (replicate n (Outputable.char '|')) mkLHsOpTy :: LHsType GhcPs -> Located RdrName -> LHsType GhcPs -> LHsType GhcPs mkLHsOpTy x op y = let loc = getLoc x `combineSrcSpans` getLoc op `combineSrcSpans` getLoc y in cL loc (mkHsOpTy x op y) mkLHsDocTy :: LHsType GhcPs -> LHsDocString -> LHsType GhcPs mkLHsDocTy t doc = let loc = getLoc t `combineSrcSpans` getLoc doc in cL loc (HsDocTy noExt t doc) mkLHsDocTyMaybe :: LHsType GhcPs -> Maybe LHsDocString -> LHsType GhcPs mkLHsDocTyMaybe t = maybe t (mkLHsDocTy t)