{-| Module : GHC.Hs.Utils Description : Generic helpers for the HsSyn type. Copyright : (c) The University of Glasgow, 1992-2006 Here we collect a variety of helper functions that construct or analyse HsSyn. All these functions deal with generic HsSyn; functions which deal with the instantiated versions are located elsewhere: Parameterised by Module ---------------- ------------- GhcPs/RdrName parser/RdrHsSyn GhcRn/Name rename/RnHsSyn GhcTc/Id typecheck/TcHsSyn The @mk*@ functions attempt to construct a not-completely-useless SrcSpan from their components, compared with the @nl*@ functions which just attach noSrcSpan to everything. -} {-# LANGUAGE CPP #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE ViewPatterns #-} module GHC.Hs.Utils( -- * Terms mkHsPar, mkHsApp, mkHsAppType, mkHsAppTypes, mkHsCaseAlt, mkSimpleMatch, unguardedGRHSs, unguardedRHS, mkMatchGroup, mkMatch, mkPrefixFunRhs, mkHsLam, mkHsIf, mkHsWrap, mkLHsWrap, mkHsWrapCo, mkHsWrapCoR, mkLHsWrapCo, mkHsDictLet, mkHsLams, mkHsOpApp, mkHsDo, mkHsComp, mkHsWrapPat, mkHsWrapPatCo, mkLHsPar, mkHsCmdWrap, mkLHsCmdWrap, mkHsCmdIf, nlHsTyApp, nlHsTyApps, nlHsVar, nlHsDataCon, nlHsLit, nlHsApp, nlHsApps, nlHsSyntaxApps, nlHsIntLit, nlHsVarApps, nlHsDo, nlHsOpApp, nlHsLam, nlHsPar, nlHsIf, nlHsCase, nlList, mkLHsTupleExpr, mkLHsVarTuple, missingTupArg, typeToLHsType, -- * Constructing general big tuples -- $big_tuples mkChunkified, chunkify, -- * Bindings mkFunBind, mkVarBind, mkHsVarBind, mkSimpleGeneratedFunBind, mkTopFunBind, mkPatSynBind, isInfixFunBind, -- * Literals mkHsIntegral, mkHsFractional, mkHsIsString, mkHsString, mkHsStringPrimLit, -- * Patterns mkNPat, mkNPlusKPat, nlVarPat, nlLitPat, nlConVarPat, nlConVarPatName, nlConPat, nlConPatName, nlInfixConPat, nlNullaryConPat, nlWildConPat, nlWildPat, nlWildPatName, nlTuplePat, mkParPat, nlParPat, mkBigLHsVarTup, mkBigLHsTup, mkBigLHsVarPatTup, mkBigLHsPatTup, -- * Types mkHsAppTy, mkHsAppKindTy, mkLHsSigType, mkLHsSigWcType, mkClassOpSigs, mkHsSigEnv, nlHsAppTy, nlHsAppKindTy, nlHsTyVar, nlHsFunTy, nlHsParTy, nlHsTyConApp, -- * Stmts mkTransformStmt, mkTransformByStmt, mkBodyStmt, mkBindStmt, mkTcBindStmt, mkLastStmt, emptyTransStmt, mkGroupUsingStmt, mkGroupByUsingStmt, emptyRecStmt, emptyRecStmtName, emptyRecStmtId, mkRecStmt, unitRecStmtTc, -- * Template Haskell mkUntypedSplice, mkTypedSplice, mkHsQuasiQuote, unqualQuasiQuote, -- * Collecting binders isUnliftedHsBind, isBangedHsBind, collectLocalBinders, collectHsValBinders, collectHsBindListBinders, collectHsIdBinders, collectHsBindsBinders, collectHsBindBinders, collectMethodBinders, collectPatBinders, collectPatsBinders, collectLStmtsBinders, collectStmtsBinders, collectLStmtBinders, collectStmtBinders, hsLTyClDeclBinders, hsTyClForeignBinders, hsPatSynSelectors, getPatSynBinds, hsForeignDeclsBinders, hsGroupBinders, hsDataFamInstBinders, -- * Collecting implicit binders lStmtsImplicits, hsValBindsImplicits, lPatImplicits ) where #include "HsVersions.h" import GhcPrelude import GHC.Hs.Decls import GHC.Hs.Binds import GHC.Hs.Expr import GHC.Hs.Pat import GHC.Hs.Types import GHC.Hs.Lit import GHC.Hs.PlaceHolder import GHC.Hs.Extension import TcEvidence import RdrName import Var import TyCoRep import Type ( appTyArgFlags, splitAppTys, tyConArgFlags, tyConAppNeedsKindSig ) import TysWiredIn ( unitTy ) import TcType import DataCon import ConLike import Id import Name import NameSet hiding ( unitFV ) import NameEnv import BasicTypes import SrcLoc import FastString import Util import Bag import Outputable import Constants import Data.Either import Data.Function import Data.List {- ************************************************************************ * * Some useful helpers for constructing syntax * * ************************************************************************ These functions attempt to construct a not-completely-useless 'SrcSpan' from their components, compared with the @nl*@ functions below which just attach 'noSrcSpan' to everything. -} -- | @e => (e)@ mkHsPar :: LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) mkHsPar e = L (getLoc e) (HsPar noExtField e) mkSimpleMatch :: HsMatchContext (NameOrRdrName (IdP (GhcPass p))) -> [LPat (GhcPass p)] -> Located (body (GhcPass p)) -> LMatch (GhcPass p) (Located (body (GhcPass p))) mkSimpleMatch ctxt pats rhs = L loc $ Match { m_ext = noExtField, m_ctxt = ctxt, m_pats = pats , m_grhss = unguardedGRHSs rhs } where loc = case pats of [] -> getLoc rhs (pat:_) -> combineSrcSpans (getLoc pat) (getLoc rhs) unguardedGRHSs :: Located (body (GhcPass p)) -> GRHSs (GhcPass p) (Located (body (GhcPass p))) unguardedGRHSs rhs@(L loc _) = GRHSs noExtField (unguardedRHS loc rhs) (noLoc emptyLocalBinds) unguardedRHS :: SrcSpan -> Located (body (GhcPass p)) -> [LGRHS (GhcPass p) (Located (body (GhcPass p)))] unguardedRHS loc rhs = [L loc (GRHS noExtField [] rhs)] mkMatchGroup :: (XMG name (Located (body name)) ~ NoExtField) => Origin -> [LMatch name (Located (body name))] -> MatchGroup name (Located (body name)) mkMatchGroup origin matches = MG { mg_ext = noExtField , mg_alts = mkLocatedList matches , mg_origin = origin } mkLocatedList :: [Located a] -> Located [Located a] mkLocatedList [] = noLoc [] mkLocatedList ms = L (combineLocs (head ms) (last ms)) ms mkHsApp :: LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) mkHsApp e1 e2 = addCLoc e1 e2 (HsApp noExtField e1 e2) mkHsAppType :: (NoGhcTc (GhcPass id) ~ GhcRn) => LHsExpr (GhcPass id) -> LHsWcType GhcRn -> LHsExpr (GhcPass id) mkHsAppType e t = addCLoc e t_body (HsAppType noExtField e paren_wct) where t_body = hswc_body t paren_wct = t { hswc_body = parenthesizeHsType appPrec t_body } mkHsAppTypes :: LHsExpr GhcRn -> [LHsWcType GhcRn] -> LHsExpr GhcRn mkHsAppTypes = foldl' mkHsAppType mkHsLam :: (XMG (GhcPass p) (LHsExpr (GhcPass p)) ~ NoExtField) => [LPat (GhcPass p)] -> LHsExpr (GhcPass p) -> LHsExpr (GhcPass p) mkHsLam pats body = mkHsPar (L (getLoc body) (HsLam noExtField matches)) where matches = mkMatchGroup Generated [mkSimpleMatch LambdaExpr pats' body] pats' = map (parenthesizePat appPrec) pats mkHsLams :: [TyVar] -> [EvVar] -> LHsExpr GhcTc -> LHsExpr GhcTc mkHsLams tyvars dicts expr = mkLHsWrap (mkWpTyLams tyvars <.> mkWpLams dicts) expr -- |A simple case alternative with a single pattern, no binds, no guards; -- pre-typechecking mkHsCaseAlt :: LPat (GhcPass p) -> (Located (body (GhcPass p))) -> LMatch (GhcPass p) (Located (body (GhcPass p))) mkHsCaseAlt pat expr = mkSimpleMatch CaseAlt [pat] expr nlHsTyApp :: IdP (GhcPass id) -> [Type] -> LHsExpr (GhcPass id) nlHsTyApp fun_id tys = noLoc (mkHsWrap (mkWpTyApps tys) (HsVar noExtField (noLoc fun_id))) nlHsTyApps :: IdP (GhcPass id) -> [Type] -> [LHsExpr (GhcPass id)] -> LHsExpr (GhcPass id) nlHsTyApps fun_id tys xs = foldl' nlHsApp (nlHsTyApp fun_id tys) xs --------- Adding parens --------- -- | Wrap in parens if @'hsExprNeedsParens' appPrec@ says it needs them -- So @f x@ becomes @(f x)@, but @3@ stays as @3@. mkLHsPar :: LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) mkLHsPar le@(L loc e) | hsExprNeedsParens appPrec e = L loc (HsPar noExtField le) | otherwise = le mkParPat :: LPat (GhcPass name) -> LPat (GhcPass name) mkParPat lp@(L loc p) | patNeedsParens appPrec p = L loc (ParPat noExtField lp) | otherwise = lp nlParPat :: LPat (GhcPass name) -> LPat (GhcPass name) nlParPat p = noLoc (ParPat noExtField p) ------------------------------- -- These are the bits of syntax that contain rebindable names -- See GHC.Rename.Env.lookupSyntaxName mkHsIntegral :: IntegralLit -> HsOverLit GhcPs mkHsFractional :: FractionalLit -> HsOverLit GhcPs mkHsIsString :: SourceText -> FastString -> HsOverLit GhcPs mkHsDo :: HsStmtContext Name -> [ExprLStmt GhcPs] -> HsExpr GhcPs mkHsComp :: HsStmtContext Name -> [ExprLStmt GhcPs] -> LHsExpr GhcPs -> HsExpr GhcPs mkNPat :: Located (HsOverLit GhcPs) -> Maybe (SyntaxExpr GhcPs) -> Pat GhcPs mkNPlusKPat :: Located RdrName -> Located (HsOverLit GhcPs) -> Pat GhcPs mkLastStmt :: Located (bodyR (GhcPass idR)) -> StmtLR (GhcPass idL) (GhcPass idR) (Located (bodyR (GhcPass idR))) mkBodyStmt :: Located (bodyR GhcPs) -> StmtLR (GhcPass idL) GhcPs (Located (bodyR GhcPs)) mkBindStmt :: (XBindStmt (GhcPass idL) (GhcPass idR) (Located (bodyR (GhcPass idR))) ~ NoExtField) => LPat (GhcPass idL) -> Located (bodyR (GhcPass idR)) -> StmtLR (GhcPass idL) (GhcPass idR) (Located (bodyR (GhcPass idR))) mkTcBindStmt :: LPat GhcTc -> Located (bodyR GhcTc) -> StmtLR GhcTc GhcTc (Located (bodyR GhcTc)) emptyRecStmt :: StmtLR (GhcPass idL) GhcPs bodyR emptyRecStmtName :: StmtLR GhcRn GhcRn bodyR emptyRecStmtId :: StmtLR GhcTc GhcTc bodyR mkRecStmt :: [LStmtLR (GhcPass idL) GhcPs bodyR] -> StmtLR (GhcPass idL) GhcPs bodyR mkHsIntegral i = OverLit noExtField (HsIntegral i) noExpr mkHsFractional f = OverLit noExtField (HsFractional f) noExpr mkHsIsString src s = OverLit noExtField (HsIsString src s) noExpr mkHsDo ctxt stmts = HsDo noExtField ctxt (mkLocatedList stmts) mkHsComp ctxt stmts expr = mkHsDo ctxt (stmts ++ [last_stmt]) where last_stmt = L (getLoc expr) $ mkLastStmt expr mkHsIf :: LHsExpr (GhcPass p) -> LHsExpr (GhcPass p) -> LHsExpr (GhcPass p) -> HsExpr (GhcPass p) mkHsIf c a b = HsIf noExtField (Just noSyntaxExpr) c a b mkHsCmdIf :: LHsExpr (GhcPass p) -> LHsCmd (GhcPass p) -> LHsCmd (GhcPass p) -> HsCmd (GhcPass p) mkHsCmdIf c a b = HsCmdIf noExtField (Just noSyntaxExpr) c a b mkNPat lit neg = NPat noExtField lit neg noSyntaxExpr mkNPlusKPat id lit = NPlusKPat noExtField id lit (unLoc lit) noSyntaxExpr noSyntaxExpr mkTransformStmt :: [ExprLStmt GhcPs] -> LHsExpr GhcPs -> StmtLR GhcPs GhcPs (LHsExpr GhcPs) mkTransformByStmt :: [ExprLStmt GhcPs] -> LHsExpr GhcPs -> LHsExpr GhcPs -> StmtLR GhcPs GhcPs (LHsExpr GhcPs) mkGroupUsingStmt :: [ExprLStmt GhcPs] -> LHsExpr GhcPs -> StmtLR GhcPs GhcPs (LHsExpr GhcPs) mkGroupByUsingStmt :: [ExprLStmt GhcPs] -> LHsExpr GhcPs -> LHsExpr GhcPs -> StmtLR GhcPs GhcPs (LHsExpr GhcPs) emptyTransStmt :: StmtLR GhcPs GhcPs (LHsExpr GhcPs) emptyTransStmt = TransStmt { trS_ext = noExtField , trS_form = panic "emptyTransStmt: form" , trS_stmts = [], trS_bndrs = [] , trS_by = Nothing, trS_using = noLoc noExpr , trS_ret = noSyntaxExpr, trS_bind = noSyntaxExpr , trS_fmap = noExpr } mkTransformStmt ss u = emptyTransStmt { trS_form = ThenForm, trS_stmts = ss, trS_using = u } mkTransformByStmt ss u b = emptyTransStmt { trS_form = ThenForm, trS_stmts = ss, trS_using = u, trS_by = Just b } mkGroupUsingStmt ss u = emptyTransStmt { trS_form = GroupForm, trS_stmts = ss, trS_using = u } mkGroupByUsingStmt ss b u = emptyTransStmt { trS_form = GroupForm, trS_stmts = ss, trS_using = u, trS_by = Just b } mkLastStmt body = LastStmt noExtField body False noSyntaxExpr mkBodyStmt body = BodyStmt noExtField body noSyntaxExpr noSyntaxExpr mkBindStmt pat body = BindStmt noExtField pat body noSyntaxExpr noSyntaxExpr mkTcBindStmt pat body = BindStmt unitTy pat body noSyntaxExpr noSyntaxExpr -- don't use placeHolderTypeTc above, because that panics during zonking emptyRecStmt' :: forall idL idR body. XRecStmt (GhcPass idL) (GhcPass idR) body -> StmtLR (GhcPass idL) (GhcPass idR) body emptyRecStmt' tyVal = RecStmt { recS_stmts = [], recS_later_ids = [] , recS_rec_ids = [] , recS_ret_fn = noSyntaxExpr , recS_mfix_fn = noSyntaxExpr , recS_bind_fn = noSyntaxExpr , recS_ext = tyVal } unitRecStmtTc :: RecStmtTc unitRecStmtTc = RecStmtTc { recS_bind_ty = unitTy , recS_later_rets = [] , recS_rec_rets = [] , recS_ret_ty = unitTy } emptyRecStmt = emptyRecStmt' noExtField emptyRecStmtName = emptyRecStmt' noExtField emptyRecStmtId = emptyRecStmt' unitRecStmtTc -- a panic might trigger during zonking mkRecStmt stmts = emptyRecStmt { recS_stmts = stmts } ------------------------------- -- | A useful function for building @OpApps@. The operator is always a -- variable, and we don't know the fixity yet. mkHsOpApp :: LHsExpr GhcPs -> IdP GhcPs -> LHsExpr GhcPs -> HsExpr GhcPs mkHsOpApp e1 op e2 = OpApp noExtField e1 (noLoc (HsVar noExtField (noLoc op))) e2 unqualSplice :: RdrName unqualSplice = mkRdrUnqual (mkVarOccFS (fsLit "splice")) mkUntypedSplice :: SpliceDecoration -> LHsExpr GhcPs -> HsSplice GhcPs mkUntypedSplice hasParen e = HsUntypedSplice noExtField hasParen unqualSplice e mkTypedSplice :: SpliceDecoration -> LHsExpr GhcPs -> HsSplice GhcPs mkTypedSplice hasParen e = HsTypedSplice noExtField hasParen unqualSplice e mkHsQuasiQuote :: RdrName -> SrcSpan -> FastString -> HsSplice GhcPs mkHsQuasiQuote quoter span quote = HsQuasiQuote noExtField unqualSplice quoter span quote unqualQuasiQuote :: RdrName unqualQuasiQuote = mkRdrUnqual (mkVarOccFS (fsLit "quasiquote")) -- A name (uniquified later) to -- identify the quasi-quote mkHsString :: String -> HsLit (GhcPass p) mkHsString s = HsString NoSourceText (mkFastString s) mkHsStringPrimLit :: FastString -> HsLit (GhcPass p) mkHsStringPrimLit fs = HsStringPrim NoSourceText (bytesFS fs) {- ************************************************************************ * * Constructing syntax with no location info * * ************************************************************************ -} nlHsVar :: IdP (GhcPass id) -> LHsExpr (GhcPass id) nlHsVar n = noLoc (HsVar noExtField (noLoc n)) -- | NB: Only for 'LHsExpr' 'Id'. nlHsDataCon :: DataCon -> LHsExpr GhcTc nlHsDataCon con = noLoc (HsConLikeOut noExtField (RealDataCon con)) nlHsLit :: HsLit (GhcPass p) -> LHsExpr (GhcPass p) nlHsLit n = noLoc (HsLit noExtField n) nlHsIntLit :: Integer -> LHsExpr (GhcPass p) nlHsIntLit n = noLoc (HsLit noExtField (HsInt noExtField (mkIntegralLit n))) nlVarPat :: IdP (GhcPass id) -> LPat (GhcPass id) nlVarPat n = noLoc (VarPat noExtField (noLoc n)) nlLitPat :: HsLit GhcPs -> LPat GhcPs nlLitPat l = noLoc (LitPat noExtField l) nlHsApp :: LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) nlHsApp f x = noLoc (HsApp noExtField f (mkLHsPar x)) nlHsSyntaxApps :: SyntaxExpr (GhcPass id) -> [LHsExpr (GhcPass id)] -> LHsExpr (GhcPass id) nlHsSyntaxApps (SyntaxExpr { syn_expr = fun , syn_arg_wraps = arg_wraps , syn_res_wrap = res_wrap }) args | [] <- arg_wraps -- in the noSyntaxExpr case = ASSERT( isIdHsWrapper res_wrap ) foldl' nlHsApp (noLoc fun) args | otherwise = mkLHsWrap res_wrap (foldl' nlHsApp (noLoc fun) (zipWithEqual "nlHsSyntaxApps" mkLHsWrap arg_wraps args)) nlHsApps :: IdP (GhcPass id) -> [LHsExpr (GhcPass id)] -> LHsExpr (GhcPass id) nlHsApps f xs = foldl' nlHsApp (nlHsVar f) xs nlHsVarApps :: IdP (GhcPass id) -> [IdP (GhcPass id)] -> LHsExpr (GhcPass id) nlHsVarApps f xs = noLoc (foldl' mk (HsVar noExtField (noLoc f)) (map ((HsVar noExtField) . noLoc) xs)) where mk f a = HsApp noExtField (noLoc f) (noLoc a) nlConVarPat :: RdrName -> [RdrName] -> LPat GhcPs nlConVarPat con vars = nlConPat con (map nlVarPat vars) nlConVarPatName :: Name -> [Name] -> LPat GhcRn nlConVarPatName con vars = nlConPatName con (map nlVarPat vars) nlInfixConPat :: RdrName -> LPat GhcPs -> LPat GhcPs -> LPat GhcPs nlInfixConPat con l r = noLoc (ConPatIn (noLoc con) (InfixCon (parenthesizePat opPrec l) (parenthesizePat opPrec r))) nlConPat :: RdrName -> [LPat GhcPs] -> LPat GhcPs nlConPat con pats = noLoc (ConPatIn (noLoc con) (PrefixCon (map (parenthesizePat appPrec) pats))) nlConPatName :: Name -> [LPat GhcRn] -> LPat GhcRn nlConPatName con pats = noLoc (ConPatIn (noLoc con) (PrefixCon (map (parenthesizePat appPrec) pats))) nlNullaryConPat :: IdP (GhcPass p) -> LPat (GhcPass p) nlNullaryConPat con = noLoc (ConPatIn (noLoc con) (PrefixCon [])) nlWildConPat :: DataCon -> LPat GhcPs nlWildConPat con = noLoc (ConPatIn (noLoc (getRdrName con)) (PrefixCon (replicate (dataConSourceArity con) nlWildPat))) -- | Wildcard pattern - after parsing nlWildPat :: LPat GhcPs nlWildPat = noLoc (WildPat noExtField ) -- | Wildcard pattern - after renaming nlWildPatName :: LPat GhcRn nlWildPatName = noLoc (WildPat noExtField ) nlHsDo :: HsStmtContext Name -> [LStmt GhcPs (LHsExpr GhcPs)] -> LHsExpr GhcPs nlHsDo ctxt stmts = noLoc (mkHsDo ctxt stmts) nlHsOpApp :: LHsExpr GhcPs -> IdP GhcPs -> LHsExpr GhcPs -> LHsExpr GhcPs nlHsOpApp e1 op e2 = noLoc (mkHsOpApp e1 op e2) nlHsLam :: LMatch GhcPs (LHsExpr GhcPs) -> LHsExpr GhcPs nlHsPar :: LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) nlHsIf :: LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) nlHsCase :: LHsExpr GhcPs -> [LMatch GhcPs (LHsExpr GhcPs)] -> LHsExpr GhcPs nlList :: [LHsExpr GhcPs] -> LHsExpr GhcPs nlHsLam match = noLoc (HsLam noExtField (mkMatchGroup Generated [match])) nlHsPar e = noLoc (HsPar noExtField e) -- | Note [Rebindable nlHsIf] -- nlHsIf should generate if-expressions which are NOT subject to -- RebindableSyntax, so the first field of HsIf is Nothing. (#12080) nlHsIf cond true false = noLoc (HsIf noExtField Nothing cond true false) nlHsCase expr matches = noLoc (HsCase noExtField expr (mkMatchGroup Generated matches)) nlList exprs = noLoc (ExplicitList noExtField Nothing exprs) nlHsAppTy :: LHsType (GhcPass p) -> LHsType (GhcPass p) -> LHsType (GhcPass p) nlHsTyVar :: IdP (GhcPass p) -> LHsType (GhcPass p) nlHsFunTy :: LHsType (GhcPass p) -> LHsType (GhcPass p) -> LHsType (GhcPass p) nlHsParTy :: LHsType (GhcPass p) -> LHsType (GhcPass p) nlHsAppTy f t = noLoc (HsAppTy noExtField f (parenthesizeHsType appPrec t)) nlHsTyVar x = noLoc (HsTyVar noExtField NotPromoted (noLoc x)) nlHsFunTy a b = noLoc (HsFunTy noExtField (parenthesizeHsType funPrec a) b) nlHsParTy t = noLoc (HsParTy noExtField t) nlHsTyConApp :: IdP (GhcPass p) -> [LHsType (GhcPass p)] -> LHsType (GhcPass p) nlHsTyConApp tycon tys = foldl' nlHsAppTy (nlHsTyVar tycon) tys nlHsAppKindTy :: LHsType (GhcPass p) -> LHsKind (GhcPass p) -> LHsType (GhcPass p) nlHsAppKindTy f k = noLoc (HsAppKindTy noSrcSpan f (parenthesizeHsType appPrec k)) {- Tuples. All these functions are *pre-typechecker* because they lack types on the tuple. -} mkLHsTupleExpr :: [LHsExpr (GhcPass a)] -> LHsExpr (GhcPass a) -- Makes a pre-typechecker boxed tuple, deals with 1 case mkLHsTupleExpr [e] = e mkLHsTupleExpr es = noLoc $ ExplicitTuple noExtField (map (noLoc . (Present noExtField)) es) Boxed mkLHsVarTuple :: [IdP (GhcPass a)] -> LHsExpr (GhcPass a) mkLHsVarTuple ids = mkLHsTupleExpr (map nlHsVar ids) nlTuplePat :: [LPat GhcPs] -> Boxity -> LPat GhcPs nlTuplePat pats box = noLoc (TuplePat noExtField pats box) missingTupArg :: HsTupArg GhcPs missingTupArg = Missing noExtField mkLHsPatTup :: [LPat GhcRn] -> LPat GhcRn mkLHsPatTup [] = noLoc $ TuplePat noExtField [] Boxed mkLHsPatTup [lpat] = lpat mkLHsPatTup lpats = L (getLoc (head lpats)) $ TuplePat noExtField lpats Boxed -- | The Big equivalents for the source tuple expressions mkBigLHsVarTup :: [IdP (GhcPass id)] -> LHsExpr (GhcPass id) mkBigLHsVarTup ids = mkBigLHsTup (map nlHsVar ids) mkBigLHsTup :: [LHsExpr (GhcPass id)] -> LHsExpr (GhcPass id) mkBigLHsTup = mkChunkified mkLHsTupleExpr -- | The Big equivalents for the source tuple patterns mkBigLHsVarPatTup :: [IdP GhcRn] -> LPat GhcRn mkBigLHsVarPatTup bs = mkBigLHsPatTup (map nlVarPat bs) mkBigLHsPatTup :: [LPat GhcRn] -> LPat GhcRn mkBigLHsPatTup = mkChunkified mkLHsPatTup -- $big_tuples -- #big_tuples# -- -- GHCs built in tuples can only go up to 'mAX_TUPLE_SIZE' in arity, but -- we might concievably want to build such a massive tuple as part of the -- output of a desugaring stage (notably that for list comprehensions). -- -- We call tuples above this size \"big tuples\", and emulate them by -- creating and pattern matching on >nested< tuples that are expressible -- by GHC. -- -- Nesting policy: it's better to have a 2-tuple of 10-tuples (3 objects) -- than a 10-tuple of 2-tuples (11 objects), so we want the leaves of any -- construction to be big. -- -- If you just use the 'mkBigCoreTup', 'mkBigCoreVarTupTy', 'mkTupleSelector' -- and 'mkTupleCase' functions to do all your work with tuples you should be -- fine, and not have to worry about the arity limitation at all. -- | Lifts a \"small\" constructor into a \"big\" constructor by recursive decompositon mkChunkified :: ([a] -> a) -- ^ \"Small\" constructor function, of maximum input arity 'mAX_TUPLE_SIZE' -> [a] -- ^ Possible \"big\" list of things to construct from -> a -- ^ Constructed thing made possible by recursive decomposition mkChunkified small_tuple as = mk_big_tuple (chunkify as) where -- Each sub-list is short enough to fit in a tuple mk_big_tuple [as] = small_tuple as mk_big_tuple as_s = mk_big_tuple (chunkify (map small_tuple as_s)) chunkify :: [a] -> [[a]] -- ^ Split a list into lists that are small enough to have a corresponding -- tuple arity. The sub-lists of the result all have length <= 'mAX_TUPLE_SIZE' -- But there may be more than 'mAX_TUPLE_SIZE' sub-lists chunkify xs | n_xs <= mAX_TUPLE_SIZE = [xs] | otherwise = split xs where n_xs = length xs split [] = [] split xs = take mAX_TUPLE_SIZE xs : split (drop mAX_TUPLE_SIZE xs) {- ************************************************************************ * * LHsSigType and LHsSigWcType * * ********************************************************************* -} mkLHsSigType :: LHsType GhcPs -> LHsSigType GhcPs mkLHsSigType ty = mkHsImplicitBndrs ty mkLHsSigWcType :: LHsType GhcPs -> LHsSigWcType GhcPs mkLHsSigWcType ty = mkHsWildCardBndrs (mkHsImplicitBndrs ty) mkHsSigEnv :: forall a. (LSig GhcRn -> Maybe ([Located Name], a)) -> [LSig GhcRn] -> NameEnv a mkHsSigEnv get_info sigs = mkNameEnv (mk_pairs ordinary_sigs) `extendNameEnvList` (mk_pairs gen_dm_sigs) -- The subtlety is this: in a class decl with a -- default-method signature as well as a method signature -- we want the latter to win (#12533) -- class C x where -- op :: forall a . x a -> x a -- default op :: forall b . x b -> x b -- op x = ...(e :: b -> b)... -- The scoped type variables of the 'default op', namely 'b', -- scope over the code for op. The 'forall a' does not! -- This applies both in the renamer and typechecker, both -- of which use this function where (gen_dm_sigs, ordinary_sigs) = partition is_gen_dm_sig sigs is_gen_dm_sig (L _ (ClassOpSig _ True _ _)) = True is_gen_dm_sig _ = False mk_pairs :: [LSig GhcRn] -> [(Name, a)] mk_pairs sigs = [ (n,a) | Just (ns,a) <- map get_info sigs , L _ n <- ns ] mkClassOpSigs :: [LSig GhcPs] -> [LSig GhcPs] -- ^ Convert 'TypeSig' to 'ClassOpSig'. -- The former is what is parsed, but the latter is -- what we need in class/instance declarations mkClassOpSigs sigs = map fiddle sigs where fiddle (L loc (TypeSig _ nms ty)) = L loc (ClassOpSig noExtField False nms (dropWildCards ty)) fiddle sig = sig typeToLHsType :: Type -> LHsType GhcPs -- ^ Converting a Type to an HsType RdrName -- This is needed to implement GeneralizedNewtypeDeriving. -- -- Note that we use 'getRdrName' extensively, which -- generates Exact RdrNames rather than strings. typeToLHsType ty = go ty where go :: Type -> LHsType GhcPs go ty@(FunTy { ft_af = af, ft_arg = arg, ft_res = res }) = case af of VisArg -> nlHsFunTy (go arg) (go res) InvisArg | (theta, tau) <- tcSplitPhiTy ty -> noLoc (HsQualTy { hst_ctxt = noLoc (map go theta) , hst_xqual = noExtField , hst_body = go tau }) go ty@(ForAllTy (Bndr _ argf) _) | (tvs, tau) <- tcSplitForAllTysSameVis argf ty = noLoc (HsForAllTy { hst_fvf = argToForallVisFlag argf , hst_bndrs = map go_tv tvs , hst_xforall = noExtField , hst_body = go tau }) go (TyVarTy tv) = nlHsTyVar (getRdrName tv) go (LitTy (NumTyLit n)) = noLoc $ HsTyLit noExtField (HsNumTy NoSourceText n) go (LitTy (StrTyLit s)) = noLoc $ HsTyLit noExtField (HsStrTy NoSourceText s) go ty@(TyConApp tc args) | tyConAppNeedsKindSig True tc (length args) -- We must produce an explicit kind signature here to make certain -- programs kind-check. See Note [Kind signatures in typeToLHsType]. = nlHsParTy $ noLoc $ HsKindSig noExtField ty' (go (tcTypeKind ty)) | otherwise = ty' where ty' :: LHsType GhcPs ty' = go_app (nlHsTyVar (getRdrName tc)) args (tyConArgFlags tc args) go ty@(AppTy {}) = go_app (go head) args (appTyArgFlags head args) where head :: Type args :: [Type] (head, args) = splitAppTys ty go (CastTy ty _) = go ty go (CoercionTy co) = pprPanic "toLHsSigWcType" (ppr co) -- Source-language types have _invisible_ kind arguments, -- so we must remove them here (#8563) go_app :: LHsType GhcPs -- The type being applied -> [Type] -- The argument types -> [ArgFlag] -- The argument types' visibilities -> LHsType GhcPs go_app head args arg_flags = foldl' (\f (arg, flag) -> let arg' = go arg in case flag of Inferred -> f Specified -> f `nlHsAppKindTy` arg' Required -> f `nlHsAppTy` arg') head (zip args arg_flags) go_tv :: TyVar -> LHsTyVarBndr GhcPs go_tv tv = noLoc $ KindedTyVar noExtField (noLoc (getRdrName tv)) (go (tyVarKind tv)) {- Note [Kind signatures in typeToLHsType] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There are types that typeToLHsType can produce which require explicit kind signatures in order to kind-check. Here is an example from #14579: -- type P :: forall {k} {t :: k}. Proxy t type P = 'Proxy -- type Wat :: forall a. Proxy a -> * newtype Wat (x :: Proxy (a :: Type)) = MkWat (Maybe a) deriving Eq -- type Wat2 :: forall {a}. Proxy a -> * type Wat2 = Wat -- type Glurp :: * -> * newtype Glurp a = MkGlurp (Wat2 (P :: Proxy a)) deriving Eq The derived Eq instance for Glurp (without any kind signatures) would be: instance Eq a => Eq (Glurp a) where (==) = coerce @(Wat2 P -> Wat2 P -> Bool) @(Glurp a -> Glurp a -> Bool) (==) :: Glurp a -> Glurp a -> Bool (Where the visible type applications use types produced by typeToLHsType.) The type P (in Wat2 P) has an underspecified kind, so we must ensure that typeToLHsType ascribes it with its kind: Wat2 (P :: Proxy a). To accomplish this, whenever we see an application of a tycon to some arguments, we use the tyConAppNeedsKindSig function to determine if it requires an explicit kind signature to resolve some ambiguity. (See Note Note [When does a tycon application need an explicit kind signature?] for a more detailed explanation of how this works.) Note that we pass True to tyConAppNeedsKindSig since we are generated code with visible kind applications, so even specified arguments count towards injective positions in the kind of the tycon. -} {- ********************************************************************* * * --------- HsWrappers: type args, dict args, casts --------- * * ********************************************************************* -} mkLHsWrap :: HsWrapper -> LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) mkLHsWrap co_fn (L loc e) = L loc (mkHsWrap co_fn e) -- | Avoid @'HsWrap' co1 ('HsWrap' co2 _)@. -- See Note [Detecting forced eta expansion] in "DsExpr" mkHsWrap :: HsWrapper -> HsExpr (GhcPass id) -> HsExpr (GhcPass id) mkHsWrap co_fn e | isIdHsWrapper co_fn = e mkHsWrap co_fn (HsWrap _ co_fn' e) = mkHsWrap (co_fn <.> co_fn') e mkHsWrap co_fn e = HsWrap noExtField co_fn e mkHsWrapCo :: TcCoercionN -- A Nominal coercion a ~N b -> HsExpr (GhcPass id) -> HsExpr (GhcPass id) mkHsWrapCo co e = mkHsWrap (mkWpCastN co) e mkHsWrapCoR :: TcCoercionR -- A Representational coercion a ~R b -> HsExpr (GhcPass id) -> HsExpr (GhcPass id) mkHsWrapCoR co e = mkHsWrap (mkWpCastR co) e mkLHsWrapCo :: TcCoercionN -> LHsExpr (GhcPass id) -> LHsExpr (GhcPass id) mkLHsWrapCo co (L loc e) = L loc (mkHsWrapCo co e) mkHsCmdWrap :: HsWrapper -> HsCmd (GhcPass p) -> HsCmd (GhcPass p) mkHsCmdWrap w cmd | isIdHsWrapper w = cmd | otherwise = HsCmdWrap noExtField w cmd mkLHsCmdWrap :: HsWrapper -> LHsCmd (GhcPass p) -> LHsCmd (GhcPass p) mkLHsCmdWrap w (L loc c) = L loc (mkHsCmdWrap w c) mkHsWrapPat :: HsWrapper -> Pat (GhcPass id) -> Type -> Pat (GhcPass id) mkHsWrapPat co_fn p ty | isIdHsWrapper co_fn = p | otherwise = CoPat noExtField co_fn p ty mkHsWrapPatCo :: TcCoercionN -> Pat (GhcPass id) -> Type -> Pat (GhcPass id) mkHsWrapPatCo co pat ty | isTcReflCo co = pat | otherwise = CoPat noExtField (mkWpCastN co) pat ty mkHsDictLet :: TcEvBinds -> LHsExpr GhcTc -> LHsExpr GhcTc mkHsDictLet ev_binds expr = mkLHsWrap (mkWpLet ev_binds) expr {- l ************************************************************************ * * Bindings; with a location at the top * * ************************************************************************ -} mkFunBind :: Origin -> Located RdrName -> [LMatch GhcPs (LHsExpr GhcPs)] -> HsBind GhcPs -- ^ Not infix, with place holders for coercion and free vars mkFunBind origin fn ms = FunBind { fun_id = fn , fun_matches = mkMatchGroup origin ms , fun_co_fn = idHsWrapper , fun_ext = noExtField , fun_tick = [] } mkTopFunBind :: Origin -> Located Name -> [LMatch GhcRn (LHsExpr GhcRn)] -> HsBind GhcRn -- ^ In Name-land, with empty bind_fvs mkTopFunBind origin fn ms = FunBind { fun_id = fn , fun_matches = mkMatchGroup origin ms , fun_co_fn = idHsWrapper , fun_ext = emptyNameSet -- NB: closed -- binding , fun_tick = [] } mkHsVarBind :: SrcSpan -> RdrName -> LHsExpr GhcPs -> LHsBind GhcPs mkHsVarBind loc var rhs = mkSimpleGeneratedFunBind loc var [] rhs mkVarBind :: IdP (GhcPass p) -> LHsExpr (GhcPass p) -> LHsBind (GhcPass p) mkVarBind var rhs = L (getLoc rhs) $ VarBind { var_ext = noExtField, var_id = var, var_rhs = rhs, var_inline = False } mkPatSynBind :: Located RdrName -> HsPatSynDetails (Located RdrName) -> LPat GhcPs -> HsPatSynDir GhcPs -> HsBind GhcPs mkPatSynBind name details lpat dir = PatSynBind noExtField psb where psb = PSB{ psb_ext = noExtField , psb_id = name , psb_args = details , psb_def = lpat , psb_dir = dir } -- |If any of the matches in the 'FunBind' are infix, the 'FunBind' is -- considered infix. isInfixFunBind :: HsBindLR id1 id2 -> Bool isInfixFunBind (FunBind _ _ (MG _ matches _) _ _) = any (isInfixMatch . unLoc) (unLoc matches) isInfixFunBind _ = False ------------ -- | Convenience function using 'mkFunBind'. -- This is for generated bindings only, do not use for user-written code. mkSimpleGeneratedFunBind :: SrcSpan -> RdrName -> [LPat GhcPs] -> LHsExpr GhcPs -> LHsBind GhcPs mkSimpleGeneratedFunBind loc fun pats expr = L loc $ mkFunBind Generated (L loc fun) [mkMatch (mkPrefixFunRhs (L loc fun)) pats expr (noLoc emptyLocalBinds)] -- | Make a prefix, non-strict function 'HsMatchContext' mkPrefixFunRhs :: Located id -> HsMatchContext id mkPrefixFunRhs n = FunRhs { mc_fun = n , mc_fixity = Prefix , mc_strictness = NoSrcStrict } ------------ mkMatch :: HsMatchContext (NameOrRdrName (IdP (GhcPass p))) -> [LPat (GhcPass p)] -> LHsExpr (GhcPass p) -> Located (HsLocalBinds (GhcPass p)) -> LMatch (GhcPass p) (LHsExpr (GhcPass p)) mkMatch ctxt pats expr lbinds = noLoc (Match { m_ext = noExtField , m_ctxt = ctxt , m_pats = map paren pats , m_grhss = GRHSs noExtField (unguardedRHS noSrcSpan expr) lbinds }) where paren lp@(L l p) | patNeedsParens appPrec p = L l (ParPat noExtField lp) | otherwise = lp {- ************************************************************************ * * Collecting binders * * ************************************************************************ Get all the binders in some HsBindGroups, IN THE ORDER OF APPEARANCE. eg. ... where (x, y) = ... f i j = ... [a, b] = ... it should return [x, y, f, a, b] (remember, order important). Note [Collect binders only after renaming] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ These functions should only be used on HsSyn *after* the renamer, to return a [Name] or [Id]. Before renaming the record punning and wild-card mechanism makes it hard to know what is bound. So these functions should not be applied to (HsSyn RdrName) Note [Unlifted id check in isUnliftedHsBind] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The function isUnliftedHsBind is used to complain if we make a top-level binding for a variable of unlifted type. Such a binding is illegal if the top-level binding would be unlifted; but also if the local letrec generated by desugaring AbsBinds would be. E.g. f :: Num a => (# a, a #) g :: Num a => a -> a f = ...g... g = ...g... The top-level bindings for f,g are not unlifted (because of the Num a =>), but the local, recursive, monomorphic bindings are: t = /\a \(d:Num a). letrec fm :: (# a, a #) = ...g... gm :: a -> a = ...f... in (fm, gm) Here the binding for 'fm' is illegal. So generally we check the abe_mono types. BUT we have a special case when abs_sig is true; see Note [The abs_sig field of AbsBinds] in GHC.Hs.Binds -} ----------------- Bindings -------------------------- -- | Should we treat this as an unlifted bind? This will be true for any -- bind that binds an unlifted variable, but we must be careful around -- AbsBinds. See Note [Unlifted id check in isUnliftedHsBind]. For usage -- information, see Note [Strict binds check] is DsBinds. isUnliftedHsBind :: HsBind GhcTc -> Bool -- works only over typechecked binds isUnliftedHsBind bind | AbsBinds { abs_exports = exports, abs_sig = has_sig } <- bind = if has_sig then any (is_unlifted_id . abe_poly) exports else any (is_unlifted_id . abe_mono) exports -- If has_sig is True we wil never generate a binding for abe_mono, -- so we don't need to worry about it being unlifted. The abe_poly -- binding might not be: e.g. forall a. Num a => (# a, a #) | otherwise = any is_unlifted_id (collectHsBindBinders bind) where is_unlifted_id id = isUnliftedType (idType id) -- | Is a binding a strict variable or pattern bind (e.g. @!x = ...@)? isBangedHsBind :: HsBind GhcTc -> Bool isBangedHsBind (AbsBinds { abs_binds = binds }) = anyBag (isBangedHsBind . unLoc) binds isBangedHsBind (FunBind {fun_matches = matches}) | [L _ match] <- unLoc $ mg_alts matches , FunRhs{mc_strictness = SrcStrict} <- m_ctxt match = True isBangedHsBind (PatBind {pat_lhs = pat}) = isBangedLPat pat isBangedHsBind _ = False collectLocalBinders :: HsLocalBindsLR (GhcPass idL) (GhcPass idR) -> [IdP (GhcPass idL)] collectLocalBinders (HsValBinds _ binds) = collectHsIdBinders binds -- No pattern synonyms here collectLocalBinders (HsIPBinds {}) = [] collectLocalBinders (EmptyLocalBinds _) = [] collectLocalBinders (XHsLocalBindsLR _) = [] collectHsIdBinders, collectHsValBinders :: HsValBindsLR (GhcPass idL) (GhcPass idR) -> [IdP (GhcPass idL)] -- ^ Collect 'Id' binders only, or 'Id's + pattern synonyms, respectively collectHsIdBinders = collect_hs_val_binders True collectHsValBinders = collect_hs_val_binders False collectHsBindBinders :: XRec pass Pat ~ Located (Pat pass) => HsBindLR pass idR -> [IdP pass] -- ^ Collect both 'Id's and pattern-synonym binders collectHsBindBinders b = collect_bind False b [] collectHsBindsBinders :: LHsBindsLR (GhcPass p) idR -> [IdP (GhcPass p)] collectHsBindsBinders binds = collect_binds False binds [] collectHsBindListBinders :: [LHsBindLR (GhcPass p) idR] -> [IdP (GhcPass p)] -- ^ Same as 'collectHsBindsBinders', but works over a list of bindings collectHsBindListBinders = foldr (collect_bind False . unLoc) [] collect_hs_val_binders :: Bool -> HsValBindsLR (GhcPass idL) (GhcPass idR) -> [IdP (GhcPass idL)] collect_hs_val_binders ps (ValBinds _ binds _) = collect_binds ps binds [] collect_hs_val_binders ps (XValBindsLR (NValBinds binds _)) = collect_out_binds ps binds collect_out_binds :: Bool -> [(RecFlag, LHsBinds (GhcPass p))] -> [IdP (GhcPass p)] collect_out_binds ps = foldr (collect_binds ps . snd) [] collect_binds :: Bool -> LHsBindsLR (GhcPass p) idR -> [IdP (GhcPass p)] -> [IdP (GhcPass p)] -- ^ Collect 'Id's, or 'Id's + pattern synonyms, depending on boolean flag collect_binds ps binds acc = foldr (collect_bind ps . unLoc) acc binds collect_bind :: XRec pass Pat ~ Located (Pat pass) => Bool -> HsBindLR pass idR -> [IdP pass] -> [IdP pass] collect_bind _ (PatBind { pat_lhs = p }) acc = collect_lpat p acc collect_bind _ (FunBind { fun_id = L _ f }) acc = f : acc collect_bind _ (VarBind { var_id = f }) acc = f : acc collect_bind _ (AbsBinds { abs_exports = dbinds }) acc = map abe_poly dbinds ++ acc -- I don't think we want the binders from the abe_binds -- binding (hence see AbsBinds) is in zonking in TcHsSyn collect_bind omitPatSyn (PatSynBind _ (PSB { psb_id = L _ ps })) acc | omitPatSyn = acc | otherwise = ps : acc collect_bind _ (PatSynBind _ (XPatSynBind _)) acc = acc collect_bind _ (XHsBindsLR _) acc = acc collectMethodBinders :: LHsBindsLR idL idR -> [Located (IdP idL)] -- ^ Used exclusively for the bindings of an instance decl which are all -- 'FunBinds' collectMethodBinders binds = foldr (get . unLoc) [] binds where get (FunBind { fun_id = f }) fs = f : fs get _ fs = fs -- Someone else complains about non-FunBinds ----------------- Statements -------------------------- collectLStmtsBinders :: [LStmtLR (GhcPass idL) (GhcPass idR) body] -> [IdP (GhcPass idL)] collectLStmtsBinders = concatMap collectLStmtBinders collectStmtsBinders :: [StmtLR (GhcPass idL) (GhcPass idR) body] -> [IdP (GhcPass idL)] collectStmtsBinders = concatMap collectStmtBinders collectLStmtBinders :: LStmtLR (GhcPass idL) (GhcPass idR) body -> [IdP (GhcPass idL)] collectLStmtBinders = collectStmtBinders . unLoc collectStmtBinders :: StmtLR (GhcPass idL) (GhcPass idR) body -> [IdP (GhcPass idL)] -- Id Binders for a Stmt... [but what about pattern-sig type vars]? collectStmtBinders (BindStmt _ pat _ _ _) = collectPatBinders pat collectStmtBinders (LetStmt _ binds) = collectLocalBinders (unLoc binds) collectStmtBinders (BodyStmt {}) = [] collectStmtBinders (LastStmt {}) = [] collectStmtBinders (ParStmt _ xs _ _) = collectLStmtsBinders $ [s | ParStmtBlock _ ss _ _ <- xs, s <- ss] collectStmtBinders (TransStmt { trS_stmts = stmts }) = collectLStmtsBinders stmts collectStmtBinders (RecStmt { recS_stmts = ss }) = collectLStmtsBinders ss collectStmtBinders (ApplicativeStmt _ args _) = concatMap collectArgBinders args where collectArgBinders (_, ApplicativeArgOne { app_arg_pattern = pat }) = collectPatBinders pat collectArgBinders (_, ApplicativeArgMany { bv_pattern = pat }) = collectPatBinders pat collectArgBinders _ = [] collectStmtBinders (XStmtLR nec) = noExtCon nec ----------------- Patterns -------------------------- collectPatBinders :: LPat (GhcPass p) -> [IdP (GhcPass p)] collectPatBinders pat = collect_lpat pat [] collectPatsBinders :: [LPat (GhcPass p)] -> [IdP (GhcPass p)] collectPatsBinders pats = foldr collect_lpat [] pats ------------- collect_lpat :: XRec pass Pat ~ Located (Pat pass) => LPat pass -> [IdP pass] -> [IdP pass] collect_lpat p bndrs = go (unLoc p) where go (VarPat _ var) = unLoc var : bndrs go (WildPat _) = bndrs go (LazyPat _ pat) = collect_lpat pat bndrs go (BangPat _ pat) = collect_lpat pat bndrs go (AsPat _ a pat) = unLoc a : collect_lpat pat bndrs go (ViewPat _ _ pat) = collect_lpat pat bndrs go (ParPat _ pat) = collect_lpat pat bndrs go (ListPat _ pats) = foldr collect_lpat bndrs pats go (TuplePat _ pats _) = foldr collect_lpat bndrs pats go (SumPat _ pat _ _) = collect_lpat pat bndrs go (ConPatIn _ ps) = foldr collect_lpat bndrs (hsConPatArgs ps) go (ConPatOut {pat_args=ps}) = foldr collect_lpat bndrs (hsConPatArgs ps) -- See Note [Dictionary binders in ConPatOut] go (LitPat _ _) = bndrs go (NPat {}) = bndrs go (NPlusKPat _ n _ _ _ _) = unLoc n : bndrs go (SigPat _ pat _) = collect_lpat pat bndrs go (SplicePat _ (HsSpliced _ _ (HsSplicedPat pat))) = go pat go (SplicePat _ _) = bndrs go (CoPat _ _ pat _) = go pat go (XPat {}) = bndrs {- Note [Dictionary binders in ConPatOut] See also same Note in DsArrows ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Do *not* gather (a) dictionary and (b) dictionary bindings as binders of a ConPatOut pattern. For most calls it doesn't matter, because it's pre-typechecker and there are no ConPatOuts. But it does matter more in the desugarer; for example, DsUtils.mkSelectorBinds uses collectPatBinders. In a lazy pattern, for example f ~(C x y) = ..., we want to generate bindings for x,y but not for dictionaries bound by C. (The type checker ensures they would not be used.) Desugaring of arrow case expressions needs these bindings (see DsArrows and arrowcase1), but SPJ (Jan 2007) says it's safer for it to use its own pat-binder-collector: Here's the problem. Consider data T a where C :: Num a => a -> Int -> T a f ~(C (n+1) m) = (n,m) Here, the pattern (C (n+1)) binds a hidden dictionary (d::Num a), and *also* uses that dictionary to match the (n+1) pattern. Yet, the variables bound by the lazy pattern are n,m, *not* the dictionary d. So in mkSelectorBinds in DsUtils, we want just m,n as the variables bound. -} hsGroupBinders :: HsGroup GhcRn -> [Name] hsGroupBinders (HsGroup { hs_valds = val_decls, hs_tyclds = tycl_decls, hs_fords = foreign_decls }) = collectHsValBinders val_decls ++ hsTyClForeignBinders tycl_decls foreign_decls hsGroupBinders (XHsGroup nec) = noExtCon nec hsTyClForeignBinders :: [TyClGroup GhcRn] -> [LForeignDecl GhcRn] -> [Name] -- We need to look at instance declarations too, -- because their associated types may bind data constructors hsTyClForeignBinders tycl_decls foreign_decls = map unLoc (hsForeignDeclsBinders foreign_decls) ++ getSelectorNames (foldMap (foldMap hsLTyClDeclBinders . group_tyclds) tycl_decls `mappend` foldMap (foldMap hsLInstDeclBinders . group_instds) tycl_decls) where getSelectorNames :: ([Located Name], [LFieldOcc GhcRn]) -> [Name] getSelectorNames (ns, fs) = map unLoc ns ++ map (extFieldOcc . unLoc) fs ------------------- hsLTyClDeclBinders :: Located (TyClDecl (GhcPass p)) -> ([Located (IdP (GhcPass p))], [LFieldOcc (GhcPass p)]) -- ^ Returns all the /binding/ names of the decl. The first one is -- guaranteed to be the name of the decl. The first component -- represents all binding names except record fields; the second -- represents field occurrences. For record fields mentioned in -- multiple constructors, the SrcLoc will be from the first occurrence. -- -- Each returned (Located name) has a SrcSpan for the /whole/ declaration. -- See Note [SrcSpan for binders] hsLTyClDeclBinders (L loc (FamDecl { tcdFam = FamilyDecl { fdLName = (L _ name) } })) = ([L loc name], []) hsLTyClDeclBinders (L _ (FamDecl { tcdFam = XFamilyDecl nec })) = noExtCon nec hsLTyClDeclBinders (L loc (SynDecl { tcdLName = (L _ name) })) = ([L loc name], []) hsLTyClDeclBinders (L loc (ClassDecl { tcdLName = (L _ cls_name) , tcdSigs = sigs , tcdATs = ats })) = (L loc cls_name : [ L fam_loc fam_name | (L fam_loc (FamilyDecl { fdLName = L _ fam_name })) <- ats ] ++ [ L mem_loc mem_name | (L mem_loc (ClassOpSig _ False ns _)) <- sigs , (L _ mem_name) <- ns ] , []) hsLTyClDeclBinders (L loc (DataDecl { tcdLName = (L _ name) , tcdDataDefn = defn })) = (\ (xs, ys) -> (L loc name : xs, ys)) $ hsDataDefnBinders defn hsLTyClDeclBinders (L _ (XTyClDecl nec)) = noExtCon nec ------------------- hsForeignDeclsBinders :: [LForeignDecl pass] -> [Located (IdP pass)] -- ^ See Note [SrcSpan for binders] hsForeignDeclsBinders foreign_decls = [ L decl_loc n | L decl_loc (ForeignImport { fd_name = L _ n }) <- foreign_decls] ------------------- hsPatSynSelectors :: HsValBinds (GhcPass p) -> [IdP (GhcPass p)] -- ^ Collects record pattern-synonym selectors only; the pattern synonym -- names are collected by 'collectHsValBinders'. hsPatSynSelectors (ValBinds _ _ _) = panic "hsPatSynSelectors" hsPatSynSelectors (XValBindsLR (NValBinds binds _)) = foldr addPatSynSelector [] . unionManyBags $ map snd binds addPatSynSelector:: LHsBind p -> [IdP p] -> [IdP p] addPatSynSelector bind sels | PatSynBind _ (PSB { psb_args = RecCon as }) <- unLoc bind = map (unLoc . recordPatSynSelectorId) as ++ sels | otherwise = sels getPatSynBinds :: [(RecFlag, LHsBinds id)] -> [PatSynBind id id] getPatSynBinds binds = [ psb | (_, lbinds) <- binds , L _ (PatSynBind _ psb) <- bagToList lbinds ] ------------------- hsLInstDeclBinders :: LInstDecl (GhcPass p) -> ([Located (IdP (GhcPass p))], [LFieldOcc (GhcPass p)]) hsLInstDeclBinders (L _ (ClsInstD { cid_inst = ClsInstDecl { cid_datafam_insts = dfis }})) = foldMap (hsDataFamInstBinders . unLoc) dfis hsLInstDeclBinders (L _ (DataFamInstD { dfid_inst = fi })) = hsDataFamInstBinders fi hsLInstDeclBinders (L _ (TyFamInstD {})) = mempty hsLInstDeclBinders (L _ (ClsInstD _ (XClsInstDecl nec))) = noExtCon nec hsLInstDeclBinders (L _ (XInstDecl nec)) = noExtCon nec ------------------- -- | the 'SrcLoc' returned are for the whole declarations, not just the names hsDataFamInstBinders :: DataFamInstDecl (GhcPass p) -> ([Located (IdP (GhcPass p))], [LFieldOcc (GhcPass p)]) hsDataFamInstBinders (DataFamInstDecl { dfid_eqn = HsIB { hsib_body = FamEqn { feqn_rhs = defn }}}) = hsDataDefnBinders defn -- There can't be repeated symbols because only data instances have binders hsDataFamInstBinders (DataFamInstDecl { dfid_eqn = HsIB { hsib_body = XFamEqn nec}}) = noExtCon nec hsDataFamInstBinders (DataFamInstDecl (XHsImplicitBndrs nec)) = noExtCon nec ------------------- -- | the 'SrcLoc' returned are for the whole declarations, not just the names hsDataDefnBinders :: HsDataDefn (GhcPass p) -> ([Located (IdP (GhcPass p))], [LFieldOcc (GhcPass p)]) hsDataDefnBinders (HsDataDefn { dd_cons = cons }) = hsConDeclsBinders cons -- See Note [Binders in family instances] hsDataDefnBinders (XHsDataDefn nec) = noExtCon nec ------------------- type Seen p = [LFieldOcc (GhcPass p)] -> [LFieldOcc (GhcPass p)] -- Filters out ones that have already been seen hsConDeclsBinders :: [LConDecl (GhcPass p)] -> ([Located (IdP (GhcPass p))], [LFieldOcc (GhcPass p)]) -- See hsLTyClDeclBinders for what this does -- The function is boringly complicated because of the records -- And since we only have equality, we have to be a little careful hsConDeclsBinders cons = go id cons where go :: Seen p -> [LConDecl (GhcPass p)] -> ([Located (IdP (GhcPass p))], [LFieldOcc (GhcPass p)]) go _ [] = ([], []) go remSeen (r:rs) -- Don't re-mangle the location of field names, because we don't -- have a record of the full location of the field declaration anyway = let loc = getLoc r in case unLoc r of -- remove only the first occurrence of any seen field in order to -- avoid circumventing detection of duplicate fields (#9156) ConDeclGADT { con_names = names, con_args = args } -> (map (L loc . unLoc) names ++ ns, flds ++ fs) where (remSeen', flds) = get_flds remSeen args (ns, fs) = go remSeen' rs ConDeclH98 { con_name = name, con_args = args } -> ([L loc (unLoc name)] ++ ns, flds ++ fs) where (remSeen', flds) = get_flds remSeen args (ns, fs) = go remSeen' rs XConDecl nec -> noExtCon nec get_flds :: Seen p -> HsConDeclDetails (GhcPass p) -> (Seen p, [LFieldOcc (GhcPass p)]) get_flds remSeen (RecCon flds) = (remSeen', fld_names) where fld_names = remSeen (concatMap (cd_fld_names . unLoc) (unLoc flds)) remSeen' = foldr (.) remSeen [deleteBy ((==) `on` unLoc . rdrNameFieldOcc . unLoc) v | v <- fld_names] get_flds remSeen _ = (remSeen, []) {- Note [SrcSpan for binders] ~~~~~~~~~~~~~~~~~~~~~~~~~~ When extracting the (Located RdrNme) for a binder, at least for the main name (the TyCon of a type declaration etc), we want to give it the @SrcSpan@ of the whole /declaration/, not just the name itself (which is how it appears in the syntax tree). This SrcSpan (for the entire declaration) is used as the SrcSpan for the Name that is finally produced, and hence for error messages. (See #8607.) Note [Binders in family instances] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In a type or data family instance declaration, the type constructor is an *occurrence* not a binding site type instance T Int = Int -> Int -- No binders data instance S Bool = S1 | S2 -- Binders are S1,S2 ************************************************************************ * * Collecting binders the user did not write * * ************************************************************************ The job of this family of functions is to run through binding sites and find the set of all Names that were defined "implicitly", without being explicitly written by the user. The main purpose is to find names introduced by record wildcards so that we can avoid warning the user when they don't use those names (#4404) Since the addition of -Wunused-record-wildcards, this function returns a pair of [(SrcSpan, [Name])]. Each element of the list is one set of implicit binders, the first component of the tuple is the document describes the possible fix to the problem (by removing the ..). This means there is some unfortunate coupling between this function and where it is used but it's only used for one specific purpose in one place so it seemed easier. -} lStmtsImplicits :: [LStmtLR GhcRn (GhcPass idR) (Located (body (GhcPass idR)))] -> [(SrcSpan, [Name])] lStmtsImplicits = hs_lstmts where hs_lstmts :: [LStmtLR GhcRn (GhcPass idR) (Located (body (GhcPass idR)))] -> [(SrcSpan, [Name])] hs_lstmts = concatMap (hs_stmt . unLoc) hs_stmt :: StmtLR GhcRn (GhcPass idR) (Located (body (GhcPass idR))) -> [(SrcSpan, [Name])] hs_stmt (BindStmt _ pat _ _ _) = lPatImplicits pat hs_stmt (ApplicativeStmt _ args _) = concatMap do_arg args where do_arg (_, ApplicativeArgOne { app_arg_pattern = pat }) = lPatImplicits pat do_arg (_, ApplicativeArgMany { app_stmts = stmts }) = hs_lstmts stmts do_arg (_, XApplicativeArg nec) = noExtCon nec hs_stmt (LetStmt _ binds) = hs_local_binds (unLoc binds) hs_stmt (BodyStmt {}) = [] hs_stmt (LastStmt {}) = [] hs_stmt (ParStmt _ xs _ _) = hs_lstmts [s | ParStmtBlock _ ss _ _ <- xs , s <- ss] hs_stmt (TransStmt { trS_stmts = stmts }) = hs_lstmts stmts hs_stmt (RecStmt { recS_stmts = ss }) = hs_lstmts ss hs_stmt (XStmtLR nec) = noExtCon nec hs_local_binds (HsValBinds _ val_binds) = hsValBindsImplicits val_binds hs_local_binds (HsIPBinds {}) = [] hs_local_binds (EmptyLocalBinds _) = [] hs_local_binds (XHsLocalBindsLR _) = [] hsValBindsImplicits :: HsValBindsLR GhcRn (GhcPass idR) -> [(SrcSpan, [Name])] hsValBindsImplicits (XValBindsLR (NValBinds binds _)) = concatMap (lhsBindsImplicits . snd) binds hsValBindsImplicits (ValBinds _ binds _) = lhsBindsImplicits binds lhsBindsImplicits :: LHsBindsLR GhcRn idR -> [(SrcSpan, [Name])] lhsBindsImplicits = foldBag (++) (lhs_bind . unLoc) [] where lhs_bind (PatBind { pat_lhs = lpat }) = lPatImplicits lpat lhs_bind _ = [] lPatImplicits :: LPat GhcRn -> [(SrcSpan, [Name])] lPatImplicits = hs_lpat where hs_lpat lpat = hs_pat (unLoc lpat) hs_lpats = foldr (\pat rest -> hs_lpat pat ++ rest) [] hs_pat (LazyPat _ pat) = hs_lpat pat hs_pat (BangPat _ pat) = hs_lpat pat hs_pat (AsPat _ _ pat) = hs_lpat pat hs_pat (ViewPat _ _ pat) = hs_lpat pat hs_pat (ParPat _ pat) = hs_lpat pat hs_pat (ListPat _ pats) = hs_lpats pats hs_pat (TuplePat _ pats _) = hs_lpats pats hs_pat (SigPat _ pat _) = hs_lpat pat hs_pat (CoPat _ _ pat _) = hs_pat pat hs_pat (ConPatIn n ps) = details n ps hs_pat (ConPatOut {pat_con=con, pat_args=ps}) = details (fmap conLikeName con) ps hs_pat _ = [] details :: Located Name -> HsConPatDetails GhcRn -> [(SrcSpan, [Name])] details _ (PrefixCon ps) = hs_lpats ps details n (RecCon fs) = [(err_loc, collectPatsBinders implicit_pats) | Just{} <- [rec_dotdot fs] ] ++ hs_lpats explicit_pats where implicit_pats = map (hsRecFieldArg . unLoc) implicit explicit_pats = map (hsRecFieldArg . unLoc) explicit (explicit, implicit) = partitionEithers [if pat_explicit then Left fld else Right fld | (i, fld) <- [0..] `zip` rec_flds fs , let pat_explicit = maybe True ((i<) . unLoc) (rec_dotdot fs)] err_loc = maybe (getLoc n) getLoc (rec_dotdot fs) details _ (InfixCon p1 p2) = hs_lpat p1 ++ hs_lpat p2