{- (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 ---------------- ------------- RdrName parser/RdrHsSyn Name rename/RnHsSyn Id typecheck/TcHsSyn -} {-# LANGUAGE CPP #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE TypeFamilies #-} module HsUtils( -- Terms mkHsPar, mkHsApp, mkHsAppType, mkHsAppTypeOut, mkHsCaseAlt, mkSimpleMatch, unguardedGRHSs, unguardedRHS, mkMatchGroup, mkMatch, mkPrefixFunRhs, mkHsLam, mkHsIf, mkHsWrap, mkLHsWrap, mkHsWrapCo, mkHsWrapCoR, mkLHsWrapCo, mkHsDictLet, mkHsLams, mkHsOpApp, mkHsDo, mkHsComp, mkHsWrapPat, mkHsWrapPatCo, mkLHsPar, mkHsCmdWrap, mkLHsCmdWrap, 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, mk_easy_FunBind, mkTopFunBind, mkPatSynBind, isInfixFunBind, -- Literals mkHsIntegral, mkHsFractional, mkHsIsString, mkHsString, mkHsStringPrimLit, -- Patterns mkNPat, mkNPlusKPat, nlVarPat, nlLitPat, nlConVarPat, nlConVarPatName, nlConPat, nlConPatName, nlInfixConPat, nlNullaryConPat, nlWildConPat, nlWildPat, nlWildPatName, nlWildPatId, nlTuplePat, mkParPat, nlParPat, mkBigLHsVarTup, mkBigLHsTup, mkBigLHsVarPatTup, mkBigLHsPatTup, -- Types mkHsAppTy, mkHsAppTys, userHsTyVarBndrs, userHsLTyVarBndrs, mkLHsSigType, mkLHsSigWcType, mkClassOpSigs, mkHsSigEnv, nlHsAppTy, nlHsTyVar, nlHsFunTy, nlHsParTy, nlHsTyConApp, -- Stmts mkTransformStmt, mkTransformByStmt, mkBodyStmt, mkBindStmt, mkTcBindStmt, mkLastStmt, emptyTransStmt, mkGroupUsingStmt, mkGroupByUsingStmt, emptyRecStmt, emptyRecStmtName, emptyRecStmtId, mkRecStmt, -- Template Haskell mkHsSpliceTy, mkHsSpliceE, mkHsSpliceTE, mkUntypedSplice, mkHsQuasiQuote, unqualQuasiQuote, -- Flags noRebindableInfo, -- Collecting binders isUnliftedHsBind, isBangedBind, collectLocalBinders, collectHsValBinders, collectHsBindListBinders, collectHsIdBinders, collectHsBindsBinders, collectHsBindBinders, collectMethodBinders, collectPatBinders, collectPatsBinders, collectLStmtsBinders, collectStmtsBinders, collectLStmtBinders, collectStmtBinders, hsLTyClDeclBinders, hsTyClForeignBinders, hsPatSynSelectors, getPatSynBinds, hsForeignDeclsBinders, hsGroupBinders, hsDataFamInstBinders, hsDataDefnBinders, -- Collecting implicit binders lStmtsImplicits, hsValBindsImplicits, lPatImplicits ) where #include "HsVersions.h" import HsDecls import HsBinds import HsExpr import HsPat import HsTypes import HsLit import PlaceHolder import TcEvidence import RdrName import Var import TyCoRep import Type ( filterOutInvisibleTypes ) import TysWiredIn ( unitTy ) import TcType import DataCon import ConLike import Id import Name import NameSet 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. -} mkHsPar :: LHsExpr id -> LHsExpr id mkHsPar e = L (getLoc e) (HsPar e) mkSimpleMatch :: HsMatchContext (NameOrRdrName id) -> [LPat id] -> Located (body id) -> LMatch id (Located (body id)) mkSimpleMatch ctxt pats rhs = L loc $ Match ctxt pats Nothing (unguardedGRHSs rhs) where loc = case pats of [] -> getLoc rhs (pat:_) -> combineSrcSpans (getLoc pat) (getLoc rhs) unguardedGRHSs :: Located (body id) -> GRHSs id (Located (body id)) unguardedGRHSs rhs@(L loc _) = GRHSs (unguardedRHS loc rhs) (noLoc emptyLocalBinds) unguardedRHS :: SrcSpan -> Located (body id) -> [LGRHS id (Located (body id))] unguardedRHS loc rhs = [L loc (GRHS [] rhs)] mkMatchGroup :: (PostTc name Type ~ PlaceHolder) => Origin -> [LMatch name (Located (body name))] -> MatchGroup name (Located (body name)) mkMatchGroup origin matches = MG { mg_alts = mkLocatedList matches , mg_arg_tys = [] , mg_res_ty = placeHolderType , mg_origin = origin } mkLocatedList :: [Located a] -> Located [Located a] mkLocatedList [] = noLoc [] mkLocatedList ms = L (combineLocs (head ms) (last ms)) ms mkHsApp :: LHsExpr name -> LHsExpr name -> LHsExpr name mkHsApp e1 e2 = addCLoc e1 e2 (HsApp e1 e2) mkHsAppType :: LHsExpr name -> LHsWcType name -> LHsExpr name mkHsAppType e t = addCLoc e (hswc_body t) (HsAppType e t) mkHsAppTypeOut :: LHsExpr Id -> LHsWcType Name -> LHsExpr Id mkHsAppTypeOut e t = addCLoc e (hswc_body t) (HsAppTypeOut e t) mkHsLam :: [LPat RdrName] -> LHsExpr RdrName -> LHsExpr RdrName mkHsLam pats body = mkHsPar (L (getLoc body) (HsLam matches)) where matches = mkMatchGroup Generated [mkSimpleMatch LambdaExpr pats body] mkHsLams :: [TyVar] -> [EvVar] -> LHsExpr Id -> LHsExpr Id 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 id -> (Located (body id)) -> LMatch id (Located (body id)) mkHsCaseAlt pat expr = mkSimpleMatch CaseAlt [pat] expr nlHsTyApp :: name -> [Type] -> LHsExpr name nlHsTyApp fun_id tys = noLoc (HsWrap (mkWpTyApps tys) (HsVar (noLoc fun_id))) nlHsTyApps :: name -> [Type] -> [LHsExpr name] -> LHsExpr name nlHsTyApps fun_id tys xs = foldl nlHsApp (nlHsTyApp fun_id tys) xs --------- Adding parens --------- mkLHsPar :: LHsExpr name -> LHsExpr name -- Wrap in parens if hsExprNeedsParens says it needs them -- So 'f x' becomes '(f x)', but '3' stays as '3' mkLHsPar le@(L loc e) | hsExprNeedsParens e = L loc (HsPar le) | otherwise = le mkParPat :: LPat name -> LPat name mkParPat lp@(L loc p) | hsPatNeedsParens p = L loc (ParPat lp) | otherwise = lp nlParPat :: LPat name -> LPat name nlParPat p = noLoc (ParPat p) ------------------------------- -- These are the bits of syntax that contain rebindable names -- See RnEnv.lookupSyntaxName mkHsIntegral :: SourceText -> Integer -> PostTc RdrName Type -> HsOverLit RdrName mkHsFractional :: FractionalLit -> PostTc RdrName Type -> HsOverLit RdrName mkHsIsString :: SourceText -> FastString -> PostTc RdrName Type -> HsOverLit RdrName mkHsDo :: HsStmtContext Name -> [ExprLStmt RdrName] -> HsExpr RdrName mkHsComp :: HsStmtContext Name -> [ExprLStmt RdrName] -> LHsExpr RdrName -> HsExpr RdrName mkNPat :: Located (HsOverLit RdrName) -> Maybe (SyntaxExpr RdrName) -> Pat RdrName mkNPlusKPat :: Located RdrName -> Located (HsOverLit RdrName) -> Pat RdrName mkLastStmt :: Located (bodyR idR) -> StmtLR idL idR (Located (bodyR idR)) mkBodyStmt :: Located (bodyR RdrName) -> StmtLR idL RdrName (Located (bodyR RdrName)) mkBindStmt :: (PostTc idR Type ~ PlaceHolder) => LPat idL -> Located (bodyR idR) -> StmtLR idL idR (Located (bodyR idR)) mkTcBindStmt :: LPat Id -> Located (bodyR Id) -> StmtLR Id Id (Located (bodyR Id)) emptyRecStmt :: StmtLR idL RdrName bodyR emptyRecStmtName :: StmtLR Name Name bodyR emptyRecStmtId :: StmtLR Id Id bodyR mkRecStmt :: [LStmtLR idL RdrName bodyR] -> StmtLR idL RdrName bodyR mkHsIntegral src i = OverLit (HsIntegral src i) noRebindableInfo noExpr mkHsFractional f = OverLit (HsFractional f) noRebindableInfo noExpr mkHsIsString src s = OverLit (HsIsString src s) noRebindableInfo noExpr noRebindableInfo :: PlaceHolder noRebindableInfo = PlaceHolder -- Just another placeholder; mkHsDo ctxt stmts = HsDo ctxt (mkLocatedList stmts) placeHolderType mkHsComp ctxt stmts expr = mkHsDo ctxt (stmts ++ [last_stmt]) where last_stmt = L (getLoc expr) $ mkLastStmt expr mkHsIf :: LHsExpr id -> LHsExpr id -> LHsExpr id -> HsExpr id mkHsIf c a b = HsIf (Just noSyntaxExpr) c a b mkNPat lit neg = NPat lit neg noSyntaxExpr placeHolderType mkNPlusKPat id lit = NPlusKPat id lit (unLoc lit) noSyntaxExpr noSyntaxExpr placeHolderType mkTransformStmt :: (PostTc idR Type ~ PlaceHolder) => [ExprLStmt idL] -> LHsExpr idR -> StmtLR idL idR (LHsExpr idL) mkTransformByStmt :: (PostTc idR Type ~ PlaceHolder) => [ExprLStmt idL] -> LHsExpr idR -> LHsExpr idR -> StmtLR idL idR (LHsExpr idL) mkGroupUsingStmt :: (PostTc idR Type ~ PlaceHolder) => [ExprLStmt idL] -> LHsExpr idR -> StmtLR idL idR (LHsExpr idL) mkGroupByUsingStmt :: (PostTc idR Type ~ PlaceHolder) => [ExprLStmt idL] -> LHsExpr idR -> LHsExpr idR -> StmtLR idL idR (LHsExpr idL) emptyTransStmt :: (PostTc idR Type ~ PlaceHolder) => StmtLR idL idR (LHsExpr idR) emptyTransStmt = TransStmt { trS_form = panic "emptyTransStmt: form" , trS_stmts = [], trS_bndrs = [] , trS_by = Nothing, trS_using = noLoc noExpr , trS_ret = noSyntaxExpr, trS_bind = noSyntaxExpr , trS_bind_arg_ty = PlaceHolder , 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 body False noSyntaxExpr mkBodyStmt body = BodyStmt body noSyntaxExpr noSyntaxExpr placeHolderType mkBindStmt pat body = BindStmt pat body noSyntaxExpr noSyntaxExpr PlaceHolder mkTcBindStmt pat body = BindStmt pat body noSyntaxExpr noSyntaxExpr unitTy -- don't use placeHolderTypeTc above, because that panics during zonking emptyRecStmt' :: forall idL idR body. PostTc idR Type -> StmtLR idL 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_bind_ty = tyVal , recS_later_rets = [] , recS_rec_rets = [], recS_ret_ty = tyVal } emptyRecStmt = emptyRecStmt' placeHolderType emptyRecStmtName = emptyRecStmt' placeHolderType emptyRecStmtId = emptyRecStmt' unitTy -- 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 id -> id -> LHsExpr id -> HsExpr id mkHsOpApp e1 op e2 = OpApp e1 (noLoc (HsVar (noLoc op))) (error "mkOpApp:fixity") e2 unqualSplice :: RdrName unqualSplice = mkRdrUnqual (mkVarOccFS (fsLit "splice")) mkUntypedSplice :: SpliceDecoration -> LHsExpr RdrName -> HsSplice RdrName mkUntypedSplice hasParen e = HsUntypedSplice hasParen unqualSplice e mkHsSpliceE :: SpliceDecoration -> LHsExpr RdrName -> HsExpr RdrName mkHsSpliceE hasParen e = HsSpliceE (mkUntypedSplice hasParen e) mkHsSpliceTE :: SpliceDecoration -> LHsExpr RdrName -> HsExpr RdrName mkHsSpliceTE hasParen e = HsSpliceE (HsTypedSplice hasParen unqualSplice e) mkHsSpliceTy :: SpliceDecoration -> LHsExpr RdrName -> HsType RdrName mkHsSpliceTy hasParen e = HsSpliceTy (HsUntypedSplice hasParen unqualSplice e) placeHolderKind mkHsQuasiQuote :: RdrName -> SrcSpan -> FastString -> HsSplice RdrName mkHsQuasiQuote quoter span quote = HsQuasiQuote unqualSplice quoter span quote unqualQuasiQuote :: RdrName unqualQuasiQuote = mkRdrUnqual (mkVarOccFS (fsLit "quasiquote")) -- A name (uniquified later) to -- identify the quasi-quote mkHsString :: String -> HsLit mkHsString s = HsString NoSourceText (mkFastString s) mkHsStringPrimLit :: FastString -> HsLit mkHsStringPrimLit fs = HsStringPrim NoSourceText (fastStringToByteString fs) ------------- userHsLTyVarBndrs :: SrcSpan -> [Located name] -> [LHsTyVarBndr name] -- Caller sets location userHsLTyVarBndrs loc bndrs = [ L loc (UserTyVar v) | v <- bndrs ] userHsTyVarBndrs :: SrcSpan -> [name] -> [LHsTyVarBndr name] -- Caller sets location userHsTyVarBndrs loc bndrs = [ L loc (UserTyVar (L loc v)) | v <- bndrs ] {- ************************************************************************ * * Constructing syntax with no location info * * ************************************************************************ -} nlHsVar :: id -> LHsExpr id nlHsVar n = noLoc (HsVar (noLoc n)) -- NB: Only for LHsExpr **Id** nlHsDataCon :: DataCon -> LHsExpr Id nlHsDataCon con = noLoc (HsConLikeOut (RealDataCon con)) nlHsLit :: HsLit -> LHsExpr id nlHsLit n = noLoc (HsLit n) nlVarPat :: id -> LPat id nlVarPat n = noLoc (VarPat (noLoc n)) nlLitPat :: HsLit -> LPat id nlLitPat l = noLoc (LitPat l) nlHsApp :: LHsExpr id -> LHsExpr id -> LHsExpr id nlHsApp f x = noLoc (HsApp f (mkLHsPar x)) nlHsSyntaxApps :: SyntaxExpr id -> [LHsExpr id] -> LHsExpr 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)) nlHsIntLit :: Integer -> LHsExpr id nlHsIntLit n = noLoc (HsLit (HsInt NoSourceText n)) nlHsApps :: id -> [LHsExpr id] -> LHsExpr id nlHsApps f xs = foldl nlHsApp (nlHsVar f) xs nlHsVarApps :: id -> [id] -> LHsExpr id nlHsVarApps f xs = noLoc (foldl mk (HsVar (noLoc f)) (map (HsVar . noLoc) xs)) where mk f a = HsApp (noLoc f) (noLoc a) nlConVarPat :: RdrName -> [RdrName] -> LPat RdrName nlConVarPat con vars = nlConPat con (map nlVarPat vars) nlConVarPatName :: Name -> [Name] -> LPat Name nlConVarPatName con vars = nlConPatName con (map nlVarPat vars) nlInfixConPat :: id -> LPat id -> LPat id -> LPat id nlInfixConPat con l r = noLoc (ConPatIn (noLoc con) (InfixCon l r)) nlConPat :: RdrName -> [LPat RdrName] -> LPat RdrName nlConPat con pats = noLoc (ConPatIn (noLoc con) (PrefixCon pats)) nlConPatName :: Name -> [LPat Name] -> LPat Name nlConPatName con pats = noLoc (ConPatIn (noLoc con) (PrefixCon pats)) nlNullaryConPat :: id -> LPat id nlNullaryConPat con = noLoc (ConPatIn (noLoc con) (PrefixCon [])) nlWildConPat :: DataCon -> LPat RdrName nlWildConPat con = noLoc (ConPatIn (noLoc (getRdrName con)) (PrefixCon (nOfThem (dataConSourceArity con) nlWildPat))) nlWildPat :: LPat RdrName nlWildPat = noLoc (WildPat placeHolderType ) -- Pre-typechecking nlWildPatName :: LPat Name nlWildPatName = noLoc (WildPat placeHolderType ) -- Pre-typechecking nlWildPatId :: LPat Id nlWildPatId = noLoc (WildPat placeHolderTypeTc ) -- Post-typechecking nlHsDo :: HsStmtContext Name -> [LStmt RdrName (LHsExpr RdrName)] -> LHsExpr RdrName nlHsDo ctxt stmts = noLoc (mkHsDo ctxt stmts) nlHsOpApp :: LHsExpr id -> id -> LHsExpr id -> LHsExpr id nlHsOpApp e1 op e2 = noLoc (mkHsOpApp e1 op e2) nlHsLam :: LMatch RdrName (LHsExpr RdrName) -> LHsExpr RdrName nlHsPar :: LHsExpr id -> LHsExpr id nlHsIf :: LHsExpr id -> LHsExpr id -> LHsExpr id -> LHsExpr id nlHsCase :: LHsExpr RdrName -> [LMatch RdrName (LHsExpr RdrName)] -> LHsExpr RdrName nlList :: [LHsExpr RdrName] -> LHsExpr RdrName nlHsLam match = noLoc (HsLam (mkMatchGroup Generated [match])) nlHsPar e = noLoc (HsPar 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 Nothing cond true false) nlHsCase expr matches = noLoc (HsCase expr (mkMatchGroup Generated matches)) nlList exprs = noLoc (ExplicitList placeHolderType Nothing exprs) nlHsAppTy :: LHsType name -> LHsType name -> LHsType name nlHsTyVar :: name -> LHsType name nlHsFunTy :: LHsType name -> LHsType name -> LHsType name nlHsParTy :: LHsType name -> LHsType name nlHsAppTy f t = noLoc (HsAppTy f t) nlHsTyVar x = noLoc (HsTyVar NotPromoted (noLoc x)) nlHsFunTy a b = noLoc (HsFunTy a b) nlHsParTy t = noLoc (HsParTy t) nlHsTyConApp :: name -> [LHsType name] -> LHsType name nlHsTyConApp tycon tys = foldl nlHsAppTy (nlHsTyVar tycon) tys {- Tuples. All these functions are *pre-typechecker* because they lack types on the tuple. -} mkLHsTupleExpr :: [LHsExpr a] -> LHsExpr a -- Makes a pre-typechecker boxed tuple, deals with 1 case mkLHsTupleExpr [e] = e mkLHsTupleExpr es = noLoc $ ExplicitTuple (map (noLoc . Present) es) Boxed mkLHsVarTuple :: [a] -> LHsExpr a mkLHsVarTuple ids = mkLHsTupleExpr (map nlHsVar ids) nlTuplePat :: [LPat id] -> Boxity -> LPat id nlTuplePat pats box = noLoc (TuplePat pats box []) missingTupArg :: HsTupArg RdrName missingTupArg = Missing placeHolderType mkLHsPatTup :: [LPat id] -> LPat id mkLHsPatTup [] = noLoc $ TuplePat [] Boxed [] mkLHsPatTup [lpat] = lpat mkLHsPatTup lpats = L (getLoc (head lpats)) $ TuplePat lpats Boxed [] -- The Big equivalents for the source tuple expressions mkBigLHsVarTup :: [id] -> LHsExpr id mkBigLHsVarTup ids = mkBigLHsTup (map nlHsVar ids) mkBigLHsTup :: [LHsExpr id] -> LHsExpr id mkBigLHsTup = mkChunkified mkLHsTupleExpr -- The Big equivalents for the source tuple patterns mkBigLHsVarPatTup :: [id] -> LPat id mkBigLHsVarPatTup bs = mkBigLHsPatTup (map nlVarPat bs) mkBigLHsPatTup :: [LPat id] -> LPat id 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 RdrName -> LHsSigType RdrName mkLHsSigType ty = mkHsImplicitBndrs ty mkLHsSigWcType :: LHsType RdrName -> LHsSigWcType RdrName mkLHsSigWcType ty = mkHsWildCardBndrs (mkHsImplicitBndrs ty) mkHsSigEnv :: forall a. (LSig Name -> Maybe ([Located Name], a)) -> [LSig Name] -> 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 (Trac #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 Name] -> [(Name, a)] mk_pairs sigs = [ (n,a) | Just (ns,a) <- map get_info sigs , L _ n <- ns ] mkClassOpSigs :: [LSig RdrName] -> [LSig RdrName] -- 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 False nms (dropWildCards ty)) fiddle sig = sig typeToLHsType :: Type -> LHsType RdrName -- ^ 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 RdrName go ty@(FunTy arg _) | isPredTy arg , (theta, tau) <- tcSplitPhiTy ty = noLoc (HsQualTy { hst_ctxt = noLoc (map go theta) , hst_body = go tau }) go (FunTy arg res) = nlHsFunTy (go arg) (go res) go ty@(ForAllTy {}) | (tvs, tau) <- tcSplitForAllTys ty = noLoc (HsForAllTy { hst_bndrs = map go_tv tvs , hst_body = go tau }) go (TyVarTy tv) = nlHsTyVar (getRdrName tv) go (AppTy t1 t2) = nlHsAppTy (go t1) (go t2) go (LitTy (NumTyLit n)) = noLoc $ HsTyLit (HsNumTy NoSourceText n) go (LitTy (StrTyLit s)) = noLoc $ HsTyLit (HsStrTy NoSourceText s) go (TyConApp tc args) = nlHsTyConApp (getRdrName tc) (map go args') where args' = filterOutInvisibleTypes tc args 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 (Trac #8563) go_tv :: TyVar -> LHsTyVarBndr RdrName go_tv tv = noLoc $ KindedTyVar (noLoc (getRdrName tv)) (go (tyVarKind tv)) {- ********************************************************************* * * --------- HsWrappers: type args, dict args, casts --------- * * ********************************************************************* -} mkLHsWrap :: HsWrapper -> LHsExpr id -> LHsExpr id mkLHsWrap co_fn (L loc e) = L loc (mkHsWrap co_fn e) mkHsWrap :: HsWrapper -> HsExpr id -> HsExpr id mkHsWrap co_fn e | isIdHsWrapper co_fn = e | otherwise = HsWrap co_fn e mkHsWrapCo :: TcCoercionN -- A Nominal coercion a ~N b -> HsExpr id -> HsExpr id mkHsWrapCo co e = mkHsWrap (mkWpCastN co) e mkHsWrapCoR :: TcCoercionR -- A Representational coercion a ~R b -> HsExpr id -> HsExpr id mkHsWrapCoR co e = mkHsWrap (mkWpCastR co) e mkLHsWrapCo :: TcCoercionN -> LHsExpr id -> LHsExpr id mkLHsWrapCo co (L loc e) = L loc (mkHsWrapCo co e) mkHsCmdWrap :: HsWrapper -> HsCmd id -> HsCmd id mkHsCmdWrap w cmd | isIdHsWrapper w = cmd | otherwise = HsCmdWrap w cmd mkLHsCmdWrap :: HsWrapper -> LHsCmd id -> LHsCmd id mkLHsCmdWrap w (L loc c) = L loc (mkHsCmdWrap w c) mkHsWrapPat :: HsWrapper -> Pat id -> Type -> Pat id mkHsWrapPat co_fn p ty | isIdHsWrapper co_fn = p | otherwise = CoPat co_fn p ty mkHsWrapPatCo :: TcCoercionN -> Pat id -> Type -> Pat id mkHsWrapPatCo co pat ty | isTcReflCo co = pat | otherwise = CoPat (mkWpCastN co) pat ty mkHsDictLet :: TcEvBinds -> LHsExpr Id -> LHsExpr Id mkHsDictLet ev_binds expr = mkLHsWrap (mkWpLet ev_binds) expr {- l ************************************************************************ * * Bindings; with a location at the top * * ************************************************************************ -} mkFunBind :: Located RdrName -> [LMatch RdrName (LHsExpr RdrName)] -> HsBind RdrName -- Not infix, with place holders for coercion and free vars mkFunBind fn ms = FunBind { fun_id = fn , fun_matches = mkMatchGroup Generated ms , fun_co_fn = idHsWrapper , bind_fvs = placeHolderNames , fun_tick = [] } mkTopFunBind :: Origin -> Located Name -> [LMatch Name (LHsExpr Name)] -> HsBind Name -- In Name-land, with empty bind_fvs mkTopFunBind origin fn ms = FunBind { fun_id = fn , fun_matches = mkMatchGroup origin ms , fun_co_fn = idHsWrapper , bind_fvs = emptyNameSet -- NB: closed -- binding , fun_tick = [] } mkHsVarBind :: SrcSpan -> RdrName -> LHsExpr RdrName -> LHsBind RdrName mkHsVarBind loc var rhs = mk_easy_FunBind loc var [] rhs mkVarBind :: id -> LHsExpr id -> LHsBind id mkVarBind var rhs = L (getLoc rhs) $ VarBind { var_id = var, var_rhs = rhs, var_inline = False } mkPatSynBind :: Located RdrName -> HsPatSynDetails (Located RdrName) -> LPat RdrName -> HsPatSynDir RdrName -> HsBind RdrName mkPatSynBind name details lpat dir = PatSynBind psb where psb = PSB{ psb_id = name , psb_args = details , psb_def = lpat , psb_dir = dir , psb_fvs = placeHolderNames } -- |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 ------------ mk_easy_FunBind :: SrcSpan -> RdrName -> [LPat RdrName] -> LHsExpr RdrName -> LHsBind RdrName mk_easy_FunBind loc fun pats expr = L loc $ mkFunBind (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 n Prefix NoSrcStrict ------------ mkMatch :: HsMatchContext (NameOrRdrName id) -> [LPat id] -> LHsExpr id -> Located (HsLocalBinds id) -> LMatch id (LHsExpr id) mkMatch ctxt pats expr lbinds = noLoc (Match ctxt (map paren pats) Nothing (GRHSs (unguardedRHS noSrcSpan expr) lbinds)) where paren lp@(L l p) | hsPatNeedsParens p = L l (ParPat 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 isHsUnliftedBind] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Suppose there is a binding with the type (Num a => (# a, a #)). Is this a strict binding that should be disallowed at the top level? At first glance, no, because it's a function. But consider how this is desugared via AbsBinds: -- x :: Num a => (# a, a #) x = (# 3, 4 #) becomes x = \ $dictNum -> let x_mono = (# fromInteger $dictNum 3, fromInteger $dictNum 4 #) in x_mono Note that the inner let is strict. And thus if we have a bunch of mutually recursive bindings of this form, we could end up in trouble. This was shown up in #9140. But if there is a type signature on x, everything changes because of the desugaring used by AbsBindsSig: x :: Num a => (# a, a #) x = (# 3, 4 #) becomes x = \ $dictNum -> (# fromInteger $dictNum 3, fromInteger $dictNum 4 #) No strictness anymore! The bottom line here is that, for inferred types, we care about the strictness of the type after the =>. For checked types (AbsBindsSig), we care about the overall strictness. This matters. If we don't separate out the AbsBindsSig case, then GHC runs into a problem when compiling undefined :: forall (r :: RuntimeRep) (a :: TYPE r). HasCallStack => a Looking only after the =>, we cannot tell if this is strict or not. (GHC panics if you try.) Looking at the whole type, on the other hand, tells you that this is a lifted function type, with no trouble at all. -} ----------------- 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 Id -> Bool -- works only over typechecked binds isUnliftedHsBind (AbsBindsSig { abs_sig_export = id }) = isUnliftedType (idType id) isUnliftedHsBind bind = any is_unlifted_id (collectHsBindBinders bind) where is_unlifted_id id = case tcSplitSigmaTy (idType id) of (_, _, tau) -> isUnliftedType tau -- For the is_unlifted check, we need to look inside polymorphism -- and overloading. E.g. x = (# 1, True #) -- would get type forall a. Num a => (# a, Bool #) -- and we want to reject that. See Trac #9140 -- | Is a binding a strict variable bind (e.g. @!x = ...@)? isBangedBind :: HsBind Id -> Bool isBangedBind b | isBangedPatBind b = True isBangedBind (FunBind {fun_matches = matches}) | [L _ match] <- unLoc $ mg_alts matches , FunRhs{mc_strictness = SrcStrict} <- m_ctxt match = True isBangedBind _ = False collectLocalBinders :: HsLocalBindsLR idL idR -> [idL] collectLocalBinders (HsValBinds binds) = collectHsIdBinders binds -- No pattern synonyms here collectLocalBinders (HsIPBinds _) = [] collectLocalBinders EmptyLocalBinds = [] collectHsIdBinders, collectHsValBinders :: HsValBindsLR idL idR -> [idL] -- Collect Id binders only, or Ids + pattern synonyms, respectively collectHsIdBinders = collect_hs_val_binders True collectHsValBinders = collect_hs_val_binders False collectHsBindBinders :: HsBindLR idL idR -> [idL] -- Collect both Ids and pattern-synonym binders collectHsBindBinders b = collect_bind False b [] collectHsBindsBinders :: LHsBindsLR idL idR -> [idL] collectHsBindsBinders binds = collect_binds False binds [] collectHsBindListBinders :: [LHsBindLR idL idR] -> [idL] -- Same as collectHsBindsBinders, but works over a list of bindings collectHsBindListBinders = foldr (collect_bind False . unLoc) [] collect_hs_val_binders :: Bool -> HsValBindsLR idL idR -> [idL] collect_hs_val_binders ps (ValBindsIn binds _) = collect_binds ps binds [] collect_hs_val_binders ps (ValBindsOut binds _) = collect_out_binds ps binds collect_out_binds :: Bool -> [(RecFlag, LHsBinds id)] -> [id] collect_out_binds ps = foldr (collect_binds ps . snd) [] collect_binds :: Bool -> LHsBindsLR idL idR -> [idL] -> [idL] -- Collect Ids, or Ids + pattern synonyms, depending on boolean flag collect_binds ps binds acc = foldrBag (collect_bind ps . unLoc) acc binds collect_bind :: Bool -> HsBindLR idL idR -> [idL] -> [idL] 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 -- The only time we collect binders from a typechecked -- binding (hence see AbsBinds) is in zonking in TcHsSyn collect_bind _ (AbsBindsSig { abs_sig_export = poly }) acc = poly : acc collect_bind omitPatSyn (PatSynBind (PSB { psb_id = L _ ps })) acc | omitPatSyn = acc | otherwise = ps : acc collectMethodBinders :: LHsBindsLR RdrName idR -> [Located RdrName] -- Used exclusively for the bindings of an instance decl which are all FunBinds collectMethodBinders binds = foldrBag (get . unLoc) [] binds where get (FunBind { fun_id = f }) fs = f : fs get _ fs = fs -- Someone else complains about non-FunBinds ----------------- Statements -------------------------- collectLStmtsBinders :: [LStmtLR idL idR body] -> [idL] collectLStmtsBinders = concatMap collectLStmtBinders collectStmtsBinders :: [StmtLR idL idR body] -> [idL] collectStmtsBinders = concatMap collectStmtBinders collectLStmtBinders :: LStmtLR idL idR body -> [idL] collectLStmtBinders = collectStmtBinders . unLoc collectStmtBinders :: StmtLR idL idR body -> [idL] -- Id Binders for a Stmt... [but what about pattern-sig type vars]? collectStmtBinders (BindStmt pat _ _ _ _)= collectPatBinders pat collectStmtBinders (LetStmt (L _ binds)) = collectLocalBinders 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{} = [] ----------------- Patterns -------------------------- collectPatBinders :: LPat a -> [a] collectPatBinders pat = collect_lpat pat [] collectPatsBinders :: [LPat a] -> [a] collectPatsBinders pats = foldr collect_lpat [] pats ------------- collect_lpat :: LPat name -> [name] -> [name] collect_lpat (L _ pat) bndrs = go pat where go (VarPat (L _ var)) = var : bndrs go (WildPat _) = bndrs go (LazyPat pat) = collect_lpat pat bndrs go (BangPat pat) = collect_lpat pat bndrs go (AsPat (L _ a) pat) = 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 (PArrPat 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 (L _ n) _ _ _ _ _)= n : bndrs go (SigPatIn pat _) = collect_lpat pat bndrs go (SigPatOut pat _) = collect_lpat pat bndrs go (SplicePat (HsSpliced _ (HsSplicedPat pat))) = go pat go (SplicePat _) = bndrs go (CoPat _ pat _) = go pat {- 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 Name -> [Name] hsGroupBinders (HsGroup { hs_valds = val_decls, hs_tyclds = tycl_decls, hs_fords = foreign_decls }) = collectHsValBinders val_decls ++ hsTyClForeignBinders tycl_decls foreign_decls hsTyClForeignBinders :: [TyClGroup Name] -> [LForeignDecl Name] -> [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 Name]) -> [Name] getSelectorNames (ns, fs) = map unLoc ns ++ map (selectorFieldOcc.unLoc) fs ------------------- hsLTyClDeclBinders :: Located (TyClDecl name) -> ([Located name], [LFieldOcc name]) -- ^ 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 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 ------------------- hsForeignDeclsBinders :: [LForeignDecl name] -> [Located name] -- See Note [SrcSpan for binders] hsForeignDeclsBinders foreign_decls = [ L decl_loc n | L decl_loc (ForeignImport { fd_name = L _ n }) <- foreign_decls] ------------------- hsPatSynSelectors :: HsValBinds id -> [id] -- Collects record pattern-synonym selectors only; the pattern synonym -- names are collected by collectHsValBinders. hsPatSynSelectors (ValBindsIn _ _) = panic "hsPatSynSelectors" hsPatSynSelectors (ValBindsOut binds _) = foldrBag addPatSynSelector [] . unionManyBags $ map snd binds addPatSynSelector:: LHsBind id -> [id] -> [id] addPatSynSelector bind sels | L _ (PatSynBind (PSB { psb_args = RecordPatSyn as })) <- 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 name -> ([Located name], [LFieldOcc name]) 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 ------------------- -- the SrcLoc returned are for the whole declarations, not just the names hsDataFamInstBinders :: DataFamInstDecl name -> ([Located name], [LFieldOcc name]) hsDataFamInstBinders (DataFamInstDecl { dfid_defn = defn }) = hsDataDefnBinders defn -- There can't be repeated symbols because only data instances have binders ------------------- -- the SrcLoc returned are for the whole declarations, not just the names hsDataDefnBinders :: HsDataDefn name -> ([Located name], [LFieldOcc name]) hsDataDefnBinders (HsDataDefn { dd_cons = cons }) = hsConDeclsBinders cons -- See Note [Binders in family instances] ------------------- hsConDeclsBinders :: [LConDecl name] -> ([Located name], [LFieldOcc name]) -- 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 :: ([LFieldOcc name] -> [LFieldOcc name]) -> [LConDecl name] -> ([Located name], [LFieldOcc name]) 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 case r of -- remove only the first occurrence of any seen field in order to -- avoid circumventing detection of duplicate fields (#9156) L loc (ConDeclGADT { con_names = names , con_type = HsIB { hsib_body = res_ty}}) -> case tau of L _ (HsFunTy (L _ (HsAppsTy [L _ (HsAppPrefix (L _ (HsRecTy flds)))])) _res_ty) -> record_gadt flds L _ (HsFunTy (L _ (HsRecTy flds)) _res_ty) -> record_gadt flds _other -> (map (L loc . unLoc) names ++ ns, fs) where (ns, fs) = go remSeen rs where (_tvs, _cxt, tau) = splitLHsSigmaTy res_ty record_gadt flds = (map (L loc . unLoc) names ++ ns, r' ++ fs) where r' = remSeen (concatMap (cd_fld_names . unLoc) flds) remSeen' = foldr (.) remSeen [deleteBy ((==) `on` unLoc . rdrNameFieldOcc . unLoc) v | v <- r'] (ns, fs) = go remSeen' rs L loc (ConDeclH98 { con_name = name , con_details = RecCon flds }) -> ([L loc (unLoc name)] ++ ns, r' ++ fs) where r' = remSeen (concatMap (cd_fld_names . unLoc) (unLoc flds)) remSeen' = foldr (.) remSeen [deleteBy ((==) `on` unLoc . rdrNameFieldOcc . unLoc) v | v <- r'] (ns, fs) = go remSeen' rs L loc (ConDeclH98 { con_name = name }) -> ([L loc (unLoc name)] ++ ns, fs) where (ns, fs) = go remSeen rs {- 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 Trac #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) -} lStmtsImplicits :: [LStmtLR Name idR (Located (body idR))] -> NameSet lStmtsImplicits = hs_lstmts where hs_lstmts :: [LStmtLR Name idR (Located (body idR))] -> NameSet hs_lstmts = foldr (\stmt rest -> unionNameSet (hs_stmt (unLoc stmt)) rest) emptyNameSet hs_stmt :: StmtLR Name idR (Located (body idR)) -> NameSet hs_stmt (BindStmt pat _ _ _ _) = lPatImplicits pat hs_stmt (ApplicativeStmt args _ _) = unionNameSets (map do_arg args) where do_arg (_, ApplicativeArgOne pat _) = lPatImplicits pat do_arg (_, ApplicativeArgMany stmts _ _) = hs_lstmts stmts hs_stmt (LetStmt binds) = hs_local_binds (unLoc binds) hs_stmt (BodyStmt {}) = emptyNameSet hs_stmt (LastStmt {}) = emptyNameSet 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_local_binds (HsValBinds val_binds) = hsValBindsImplicits val_binds hs_local_binds (HsIPBinds _) = emptyNameSet hs_local_binds EmptyLocalBinds = emptyNameSet hsValBindsImplicits :: HsValBindsLR Name idR -> NameSet hsValBindsImplicits (ValBindsOut binds _) = foldr (unionNameSet . lhsBindsImplicits . snd) emptyNameSet binds hsValBindsImplicits (ValBindsIn binds _) = lhsBindsImplicits binds lhsBindsImplicits :: LHsBindsLR Name idR -> NameSet lhsBindsImplicits = foldBag unionNameSet (lhs_bind . unLoc) emptyNameSet where lhs_bind (PatBind { pat_lhs = lpat }) = lPatImplicits lpat lhs_bind _ = emptyNameSet lPatImplicits :: LPat Name -> NameSet lPatImplicits = hs_lpat where hs_lpat (L _ pat) = hs_pat pat hs_lpats = foldr (\pat rest -> hs_lpat pat `unionNameSet` rest) emptyNameSet 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 (PArrPat pats _) = hs_lpats pats hs_pat (TuplePat pats _ _) = hs_lpats pats hs_pat (SigPatIn pat _) = hs_lpat pat hs_pat (SigPatOut pat _) = hs_lpat pat hs_pat (CoPat _ pat _) = hs_pat pat hs_pat (ConPatIn _ ps) = details ps hs_pat (ConPatOut {pat_args=ps}) = details ps hs_pat _ = emptyNameSet details (PrefixCon ps) = hs_lpats ps details (RecCon fs) = hs_lpats explicit `unionNameSet` mkNameSet (collectPatsBinders implicit) where (explicit, implicit) = partitionEithers [if pat_explicit then Left pat else Right pat | (i, fld) <- [0..] `zip` rec_flds fs , let pat = hsRecFieldArg (unLoc fld) pat_explicit = maybe True (i<) (rec_dotdot fs)] details (InfixCon p1 p2) = hs_lpat p1 `unionNameSet` hs_lpat p2