{-# LANGUAGE CPP #-} {-# LANGUAGE ConstraintKinds #-} {-# LANGUAGE DataKinds #-} {-# LANGUAGE DeriveDataTypeable #-} {-# LANGUAGE ExistentialQuantification #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE LambdaCase #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE StandaloneDeriving #-} {-# LANGUAGE TypeApplications #-} {-# LANGUAGE TypeFamilyDependencies #-} {-# LANGUAGE UndecidableInstances #-} -- Wrinkle in Note [Trees That Grow] -- in module Language.Haskell.Syntax.Extension {-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-} {-# OPTIONS_GHC -Wno-orphans #-} -- Outputable {- (c) The University of Glasgow 2006 (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 -} -- | Abstract Haskell syntax for expressions. module GHC.Hs.Expr ( module Language.Haskell.Syntax.Expr , module GHC.Hs.Expr ) where import Language.Haskell.Syntax.Expr -- friends: import GHC.Prelude import GHC.Hs.Decls import GHC.Hs.Pat import GHC.Hs.Lit import Language.Haskell.Syntax.Extension import GHC.Hs.Extension import GHC.Hs.Type import GHC.Hs.Binds import GHC.Parser.Annotation -- others: import GHC.Tc.Types.Evidence import GHC.Core.DataCon (FieldLabelString) import GHC.Types.Name import GHC.Types.Name.Set import GHC.Types.Basic import GHC.Types.Fixity import GHC.Types.SourceText import GHC.Types.SrcLoc import GHC.Types.Tickish (CoreTickish) import GHC.Core.ConLike import GHC.Unit.Module (ModuleName) import GHC.Utils.Misc import GHC.Utils.Outputable import GHC.Utils.Panic import GHC.Utils.Panic.Plain import GHC.Data.FastString import GHC.Core.Type import GHC.Builtin.Types (mkTupleStr) import GHC.Tc.Utils.TcType (TcType, TcTyVar) import {-# SOURCE #-} GHC.Tc.Types (TcLclEnv) -- libraries: import Data.Data hiding (Fixity(..)) import qualified Data.Data as Data (Fixity(..)) import qualified Data.Kind import Data.Maybe (isJust) import Data.Foldable ( toList ) import Data.List (uncons) import Data.Bifunctor (first) {- ********************************************************************* * * Expressions proper * * ********************************************************************* -} -- | Post-Type checking Expression -- -- PostTcExpr is an evidence expression attached to the syntax tree by the -- type checker (c.f. postTcType). type PostTcExpr = HsExpr GhcTc -- | Post-Type checking Table -- -- We use a PostTcTable where there are a bunch of pieces of evidence, more -- than is convenient to keep individually. type PostTcTable = [(Name, PostTcExpr)] ------------------------- -- Defining SyntaxExpr in two stages allows for better type inference, because -- we can declare SyntaxExprGhc to be injective (and closed). Without injectivity, -- noSyntaxExpr would be ambiguous. type instance SyntaxExpr (GhcPass p) = SyntaxExprGhc p type family SyntaxExprGhc (p :: Pass) = (r :: Data.Kind.Type) | r -> p where SyntaxExprGhc 'Parsed = NoExtField SyntaxExprGhc 'Renamed = SyntaxExprRn SyntaxExprGhc 'Typechecked = SyntaxExprTc -- | The function to use in rebindable syntax. See Note [NoSyntaxExpr]. data SyntaxExprRn = SyntaxExprRn (HsExpr GhcRn) -- Why is the payload not just a Name? -- See Note [Monad fail : Rebindable syntax, overloaded strings] in "GHC.Rename.Expr" | NoSyntaxExprRn -- | An expression with wrappers, used for rebindable syntax -- -- This should desugar to -- -- > syn_res_wrap $ syn_expr (syn_arg_wraps[0] arg0) -- > (syn_arg_wraps[1] arg1) ... -- -- where the actual arguments come from elsewhere in the AST. data SyntaxExprTc = SyntaxExprTc { syn_expr :: HsExpr GhcTc , syn_arg_wraps :: [HsWrapper] , syn_res_wrap :: HsWrapper } | NoSyntaxExprTc -- See Note [NoSyntaxExpr] -- | This is used for rebindable-syntax pieces that are too polymorphic -- for tcSyntaxOp (trS_fmap and the mzip in ParStmt) noExpr :: HsExpr (GhcPass p) noExpr = HsLit noComments (HsString (SourceText "noExpr") (fsLit "noExpr")) noSyntaxExpr :: forall p. IsPass p => SyntaxExpr (GhcPass p) -- Before renaming, and sometimes after -- See Note [NoSyntaxExpr] noSyntaxExpr = case ghcPass @p of GhcPs -> noExtField GhcRn -> NoSyntaxExprRn GhcTc -> NoSyntaxExprTc -- | Make a 'SyntaxExpr GhcRn' from an expression -- Used only in getMonadFailOp. -- See Note [Monad fail : Rebindable syntax, overloaded strings] in "GHC.Rename.Expr" mkSyntaxExpr :: HsExpr GhcRn -> SyntaxExprRn mkSyntaxExpr = SyntaxExprRn -- | Make a 'SyntaxExpr' from a 'Name' (the "rn" is because this is used in the -- renamer). mkRnSyntaxExpr :: Name -> SyntaxExprRn mkRnSyntaxExpr name = SyntaxExprRn $ HsVar noExtField $ noLocA name instance Outputable SyntaxExprRn where ppr (SyntaxExprRn expr) = ppr expr ppr NoSyntaxExprRn = text "" instance Outputable SyntaxExprTc where ppr (SyntaxExprTc { syn_expr = expr , syn_arg_wraps = arg_wraps , syn_res_wrap = res_wrap }) = sdocOption sdocPrintExplicitCoercions $ \print_co -> getPprDebug $ \debug -> if debug || print_co then ppr expr <> braces (pprWithCommas ppr arg_wraps) <> braces (ppr res_wrap) else ppr expr ppr NoSyntaxExprTc = text "" -- | Extra data fields for a 'RecordUpd', added by the type checker data RecordUpdTc = RecordUpdTc { rupd_cons :: [ConLike] -- Filled in by the type checker to the -- _non-empty_ list of DataCons that have -- all the upd'd fields , rupd_in_tys :: [Type] -- Argument types of *input* record type , rupd_out_tys :: [Type] -- and *output* record type -- For a data family, these are the type args of the -- /representation/ type constructor , rupd_wrap :: HsWrapper -- See Note [Record Update HsWrapper] } -- | HsWrap appears only in typechecker output data HsWrap hs_syn = HsWrap HsWrapper -- the wrapper (hs_syn GhcTc) -- the thing that is wrapped deriving instance (Data (hs_syn GhcTc), Typeable hs_syn) => Data (HsWrap hs_syn) -- --------------------------------------------------------------------- {- Note [The life cycle of a TH quotation] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When desugaring a bracket (aka quotation), we want to produce Core code that, when run, will produce the TH syntax tree for the quotation. To that end, we want to desugar /renamed/ but not /typechecked/ code; the latter is cluttered with the typechecker's elaboration that should not appear in the TH syntax tree. So in (HsExpr GhcTc) tree, we must have a (HsExpr GhcRn) for the quotation itself. As such, when typechecking both typed and untyped brackets, we keep a /renamed/ bracket in the extension field. The HsBracketTc, the GhcTc ext field for both brackets, contains: - The renamed quote :: HsQuote GhcRn -- for the desugarer - [PendingTcSplice] - The type of the quote - Maybe QuoteWrapper Note that (HsBracketTc) stores the untyped (HsQuote GhcRn) for both typed and untyped brackets. They are treated uniformly by the desugarer, and we can easily construct untyped brackets from typed ones (with ExpBr). Typed quotes ~~~~~~~~~~~~ Here is the life cycle of a /typed/ quote [|| e ||], whose datacon is HsTypedBracket (XTypedBracket p) (LHsExpr p) In pass p (XTypedBracket p) (LHsExpr p) ------------------------------------------- GhcPs Annotations only LHsExpr GhcPs GhcRn Annotations only LHsExpr GhcRn GhcTc HsBracketTc LHsExpr GhcTc: unused! Note that in the GhcTc tree, the second field (HsExpr GhcTc) is entirely unused; the desugarer uses the (HsExpr GhcRn) from the first field. Untyped quotes ~~~~~~~~~~~~~~ Here is the life cycle of an /untyped/ quote, whose datacon is HsUntypedBracket (XUntypedBracket p) (HsQuote p) Here HsQuote is a sum-type of expressions [| e |], patterns [| p |], types [| t |] etc. In pass p (XUntypedBracket p) (HsQuote p) ------------------------------------------------------- GhcPs Annotations only HsQuote GhcPs GhcRn Annotations, [PendingRnSplice] HsQuote GhcRn GhcTc HsBracketTc HsQuote GhcTc: unused! The difficulty is: the typechecker does not typecheck the body of an untyped quote, so how do we make a (HsQuote GhcTc) to put in the second field? Answer: we use the extension constructor of HsQuote, XQuote, and make all the other constructors into DataConCantHappen. That is, the only non-bottom value of type (HsQuote GhcTc) is (XQuote noExtField). Hence the instances type instance XExpBr GhcTc = DataConCantHappen ...etc... See the related Note [How brackets and nested splices are handled] in GHC.Tc.Gen.Splice -} data HsBracketTc = HsBracketTc { brack_renamed_quote :: (HsQuote GhcRn) -- See Note [The life cycle of a TH quotation] , brack_ty :: Type , brack_quote_wrapper :: (Maybe QuoteWrapper) -- The wrapper to apply type and dictionary argument to the quote. , brack_pending_splices :: [PendingTcSplice] -- Output of the type checker is the *original* -- renamed expression, plus -- _typechecked_ splices to be -- pasted back in by the desugarer } type instance XTypedBracket GhcPs = EpAnn [AddEpAnn] type instance XTypedBracket GhcRn = NoExtField type instance XTypedBracket GhcTc = HsBracketTc type instance XUntypedBracket GhcPs = EpAnn [AddEpAnn] type instance XUntypedBracket GhcRn = [PendingRnSplice] -- See Note [Pending Splices] -- Output of the renamer is the *original* renamed expression, -- plus _renamed_ splices to be type checked type instance XUntypedBracket GhcTc = HsBracketTc -- --------------------------------------------------------------------- -- API Annotations types data EpAnnHsCase = EpAnnHsCase { hsCaseAnnCase :: EpaLocation , hsCaseAnnOf :: EpaLocation , hsCaseAnnsRest :: [AddEpAnn] } deriving Data data EpAnnUnboundVar = EpAnnUnboundVar { hsUnboundBackquotes :: (EpaLocation, EpaLocation) , hsUnboundHole :: EpaLocation } deriving Data type instance XVar (GhcPass _) = NoExtField -- Record selectors at parse time are HsVar; they convert to HsRecSel -- on renaming. type instance XRecSel GhcPs = DataConCantHappen type instance XRecSel GhcRn = NoExtField type instance XRecSel GhcTc = NoExtField type instance XLam (GhcPass _) = NoExtField -- OverLabel not present in GhcTc pass; see GHC.Rename.Expr -- Note [Handling overloaded and rebindable constructs] type instance XOverLabel GhcPs = EpAnnCO type instance XOverLabel GhcRn = EpAnnCO type instance XOverLabel GhcTc = DataConCantHappen -- --------------------------------------------------------------------- type instance XVar (GhcPass _) = NoExtField type instance XUnboundVar GhcPs = EpAnn EpAnnUnboundVar type instance XUnboundVar GhcRn = NoExtField type instance XUnboundVar GhcTc = HoleExprRef -- We really don't need the whole HoleExprRef; just the IORef EvTerm -- would be enough. But then deriving a Data instance becomes impossible. -- Much, much easier just to define HoleExprRef with a Data instance and -- store the whole structure. type instance XIPVar GhcPs = EpAnnCO type instance XIPVar GhcRn = EpAnnCO type instance XIPVar GhcTc = DataConCantHappen type instance XOverLitE (GhcPass _) = EpAnnCO type instance XLitE (GhcPass _) = EpAnnCO type instance XLam (GhcPass _) = NoExtField type instance XLamCase (GhcPass _) = EpAnn [AddEpAnn] type instance XApp (GhcPass _) = EpAnnCO type instance XAppTypeE GhcPs = SrcSpan -- Where the `@` lives type instance XAppTypeE GhcRn = NoExtField type instance XAppTypeE GhcTc = Type -- OpApp not present in GhcTc pass; see GHC.Rename.Expr -- Note [Handling overloaded and rebindable constructs] type instance XOpApp GhcPs = EpAnn [AddEpAnn] type instance XOpApp GhcRn = Fixity type instance XOpApp GhcTc = DataConCantHappen -- SectionL, SectionR not present in GhcTc pass; see GHC.Rename.Expr -- Note [Handling overloaded and rebindable constructs] type instance XSectionL GhcPs = EpAnnCO type instance XSectionR GhcPs = EpAnnCO type instance XSectionL GhcRn = EpAnnCO type instance XSectionR GhcRn = EpAnnCO type instance XSectionL GhcTc = DataConCantHappen type instance XSectionR GhcTc = DataConCantHappen type instance XNegApp GhcPs = EpAnn [AddEpAnn] type instance XNegApp GhcRn = NoExtField type instance XNegApp GhcTc = NoExtField type instance XPar (GhcPass _) = EpAnnCO type instance XExplicitTuple GhcPs = EpAnn [AddEpAnn] type instance XExplicitTuple GhcRn = NoExtField type instance XExplicitTuple GhcTc = NoExtField type instance XExplicitSum GhcPs = EpAnn AnnExplicitSum type instance XExplicitSum GhcRn = NoExtField type instance XExplicitSum GhcTc = [Type] type instance XCase GhcPs = EpAnn EpAnnHsCase type instance XCase GhcRn = NoExtField type instance XCase GhcTc = NoExtField type instance XIf GhcPs = EpAnn AnnsIf type instance XIf GhcRn = NoExtField type instance XIf GhcTc = NoExtField type instance XMultiIf GhcPs = EpAnn [AddEpAnn] type instance XMultiIf GhcRn = NoExtField type instance XMultiIf GhcTc = Type type instance XLet GhcPs = EpAnnCO type instance XLet GhcRn = NoExtField type instance XLet GhcTc = NoExtField type instance XDo GhcPs = EpAnn AnnList type instance XDo GhcRn = NoExtField type instance XDo GhcTc = Type type instance XExplicitList GhcPs = EpAnn AnnList type instance XExplicitList GhcRn = NoExtField type instance XExplicitList GhcTc = Type -- GhcPs: ExplicitList includes all source-level -- list literals, including overloaded ones -- GhcRn and GhcTc: ExplicitList used only for list literals -- that denote Haskell's built-in lists. Overloaded lists -- have been expanded away in the renamer -- See Note [Handling overloaded and rebindable constructs] -- in GHC.Rename.Expr type instance XRecordCon GhcPs = EpAnn [AddEpAnn] type instance XRecordCon GhcRn = NoExtField type instance XRecordCon GhcTc = PostTcExpr -- Instantiated constructor function type instance XRecordUpd GhcPs = EpAnn [AddEpAnn] type instance XRecordUpd GhcRn = NoExtField type instance XRecordUpd GhcTc = RecordUpdTc type instance XGetField GhcPs = EpAnnCO type instance XGetField GhcRn = NoExtField type instance XGetField GhcTc = DataConCantHappen -- HsGetField is eliminated by the renamer. See [Handling overloaded -- and rebindable constructs]. type instance XProjection GhcPs = EpAnn AnnProjection type instance XProjection GhcRn = NoExtField type instance XProjection GhcTc = DataConCantHappen -- HsProjection is eliminated by the renamer. See [Handling overloaded -- and rebindable constructs]. type instance XExprWithTySig GhcPs = EpAnn [AddEpAnn] type instance XExprWithTySig GhcRn = NoExtField type instance XExprWithTySig GhcTc = NoExtField type instance XArithSeq GhcPs = EpAnn [AddEpAnn] type instance XArithSeq GhcRn = NoExtField type instance XArithSeq GhcTc = PostTcExpr type instance XSpliceE (GhcPass _) = EpAnnCO type instance XProc (GhcPass _) = EpAnn [AddEpAnn] type instance XStatic GhcPs = EpAnn [AddEpAnn] type instance XStatic GhcRn = NameSet type instance XStatic GhcTc = (NameSet, Type) -- Free variables and type of expression, this is stored for convenience as wiring in -- StaticPtr is a bit tricky (see #20150) type instance XPragE (GhcPass _) = NoExtField type instance Anno [LocatedA ((StmtLR (GhcPass pl) (GhcPass pr) (LocatedA (body (GhcPass pr)))))] = SrcSpanAnnL type instance Anno (StmtLR GhcRn GhcRn (LocatedA (body GhcRn))) = SrcSpanAnnA data AnnExplicitSum = AnnExplicitSum { aesOpen :: EpaLocation, aesBarsBefore :: [EpaLocation], aesBarsAfter :: [EpaLocation], aesClose :: EpaLocation } deriving Data data AnnFieldLabel = AnnFieldLabel { afDot :: Maybe EpaLocation } deriving Data data AnnProjection = AnnProjection { apOpen :: EpaLocation, -- ^ '(' apClose :: EpaLocation -- ^ ')' } deriving Data data AnnsIf = AnnsIf { aiIf :: EpaLocation, aiThen :: EpaLocation, aiElse :: EpaLocation, aiThenSemi :: Maybe EpaLocation, aiElseSemi :: Maybe EpaLocation } deriving Data -- --------------------------------------------------------------------- type instance XSCC (GhcPass _) = EpAnn AnnPragma type instance XXPragE (GhcPass _) = DataConCantHappen type instance XCDotFieldOcc (GhcPass _) = EpAnn AnnFieldLabel type instance XXDotFieldOcc (GhcPass _) = DataConCantHappen type instance XPresent (GhcPass _) = EpAnn [AddEpAnn] type instance XMissing GhcPs = EpAnn EpaLocation type instance XMissing GhcRn = NoExtField type instance XMissing GhcTc = Scaled Type type instance XXTupArg (GhcPass _) = DataConCantHappen tupArgPresent :: HsTupArg (GhcPass p) -> Bool tupArgPresent (Present {}) = True tupArgPresent (Missing {}) = False {- ********************************************************************* * * XXExpr: the extension constructor of HsExpr * * ********************************************************************* -} type instance XXExpr GhcPs = DataConCantHappen type instance XXExpr GhcRn = HsExpansion (HsExpr GhcRn) (HsExpr GhcRn) type instance XXExpr GhcTc = XXExprGhcTc -- HsExpansion: see Note [Rebindable syntax and HsExpansion] below data XXExprGhcTc = WrapExpr -- Type and evidence application and abstractions {-# UNPACK #-} !(HsWrap HsExpr) | ExpansionExpr -- See Note [Rebindable syntax and HsExpansion] below {-# UNPACK #-} !(HsExpansion (HsExpr GhcRn) (HsExpr GhcTc)) | ConLikeTc -- Result of typechecking a data-con -- See Note [Typechecking data constructors] in -- GHC.Tc.Gen.Head -- The two arguments describe how to eta-expand -- the data constructor when desugaring ConLike [TcTyVar] [Scaled TcType] --------------------------------------- -- Haskell program coverage (Hpc) Support | HsTick CoreTickish (LHsExpr GhcTc) -- sub-expression | HsBinTick Int -- module-local tick number for True Int -- module-local tick number for False (LHsExpr GhcTc) -- sub-expression {- ********************************************************************* * * Pretty-printing expressions * * ********************************************************************* -} instance (OutputableBndrId p) => Outputable (HsExpr (GhcPass p)) where ppr expr = pprExpr expr ----------------------- -- pprExpr, pprLExpr, pprBinds call pprDeeper; -- the underscore versions do not pprLExpr :: (OutputableBndrId p) => LHsExpr (GhcPass p) -> SDoc pprLExpr (L _ e) = pprExpr e pprExpr :: (OutputableBndrId p) => HsExpr (GhcPass p) -> SDoc pprExpr e | isAtomicHsExpr e || isQuietHsExpr e = ppr_expr e | otherwise = pprDeeper (ppr_expr e) isQuietHsExpr :: HsExpr id -> Bool -- Parentheses do display something, but it gives little info and -- if we go deeper when we go inside them then we get ugly things -- like (...) isQuietHsExpr (HsPar {}) = True -- applications don't display anything themselves isQuietHsExpr (HsApp {}) = True isQuietHsExpr (HsAppType {}) = True isQuietHsExpr (OpApp {}) = True isQuietHsExpr _ = False pprBinds :: (OutputableBndrId idL, OutputableBndrId idR) => HsLocalBindsLR (GhcPass idL) (GhcPass idR) -> SDoc pprBinds b = pprDeeper (ppr b) ----------------------- ppr_lexpr :: (OutputableBndrId p) => LHsExpr (GhcPass p) -> SDoc ppr_lexpr e = ppr_expr (unLoc e) ppr_expr :: forall p. (OutputableBndrId p) => HsExpr (GhcPass p) -> SDoc ppr_expr (HsVar _ (L _ v)) = pprPrefixOcc v ppr_expr (HsUnboundVar _ uv) = pprPrefixOcc uv ppr_expr (HsRecSel _ f) = pprPrefixOcc f ppr_expr (HsIPVar _ v) = ppr v ppr_expr (HsOverLabel _ l) = char '#' <> ppr l ppr_expr (HsLit _ lit) = ppr lit ppr_expr (HsOverLit _ lit) = ppr lit ppr_expr (HsPar _ _ e _) = parens (ppr_lexpr e) ppr_expr (HsPragE _ prag e) = sep [ppr prag, ppr_lexpr e] ppr_expr e@(HsApp {}) = ppr_apps e [] ppr_expr e@(HsAppType {}) = ppr_apps e [] ppr_expr (OpApp _ e1 op e2) | Just pp_op <- ppr_infix_expr (unLoc op) = pp_infixly pp_op | otherwise = pp_prefixly where pp_e1 = pprDebugParendExpr opPrec e1 -- In debug mode, add parens pp_e2 = pprDebugParendExpr opPrec e2 -- to make precedence clear pp_prefixly = hang (ppr op) 2 (sep [pp_e1, pp_e2]) pp_infixly pp_op = hang pp_e1 2 (sep [pp_op, nest 2 pp_e2]) ppr_expr (NegApp _ e _) = char '-' <+> pprDebugParendExpr appPrec e ppr_expr (SectionL _ expr op) | Just pp_op <- ppr_infix_expr (unLoc op) = pp_infixly pp_op | otherwise = pp_prefixly where pp_expr = pprDebugParendExpr opPrec expr pp_prefixly = hang (hsep [text " \\ x_ ->", ppr op]) 4 (hsep [pp_expr, text "x_ )"]) pp_infixly v = (sep [pp_expr, v]) ppr_expr (SectionR _ op expr) | Just pp_op <- ppr_infix_expr (unLoc op) = pp_infixly pp_op | otherwise = pp_prefixly where pp_expr = pprDebugParendExpr opPrec expr pp_prefixly = hang (hsep [text "( \\ x_ ->", ppr op, text "x_"]) 4 (pp_expr <> rparen) pp_infixly v = sep [v, pp_expr] ppr_expr (ExplicitTuple _ exprs boxity) -- Special-case unary boxed tuples so that they are pretty-printed as -- `Solo x`, not `(x)` | [Present _ expr] <- exprs , Boxed <- boxity = hsep [text (mkTupleStr Boxed 1), ppr expr] | otherwise = tupleParens (boxityTupleSort boxity) (fcat (ppr_tup_args exprs)) where ppr_tup_args [] = [] ppr_tup_args (Present _ e : es) = (ppr_lexpr e <> punc es) : ppr_tup_args es ppr_tup_args (Missing _ : es) = punc es : ppr_tup_args es punc (Present {} : _) = comma <> space punc (Missing {} : _) = comma punc (XTupArg {} : _) = comma <> space punc [] = empty ppr_expr (ExplicitSum _ alt arity expr) = text "(#" <+> ppr_bars (alt - 1) <+> ppr expr <+> ppr_bars (arity - alt) <+> text "#)" where ppr_bars n = hsep (replicate n (char '|')) ppr_expr (HsLam _ matches) = pprMatches matches ppr_expr (HsLamCase _ lc_variant matches) = sep [ sep [lamCaseKeyword lc_variant], nest 2 (pprMatches matches) ] ppr_expr (HsCase _ expr matches@(MG { mg_alts = L _ alts })) = sep [ sep [text "case", nest 4 (ppr expr), text "of"], pp_alts ] where pp_alts | null alts = text "{}" | otherwise = nest 2 (pprMatches matches) ppr_expr (HsIf _ e1 e2 e3) = sep [hsep [text "if", nest 2 (ppr e1), text "then"], nest 4 (ppr e2), text "else", nest 4 (ppr e3)] ppr_expr (HsMultiIf _ alts) = hang (text "if") 3 (vcat (map ppr_alt alts)) where ppr_alt (L _ (GRHS _ guards expr)) = hang vbar 2 (ppr_one one_alt) where ppr_one [] = panic "ppr_exp HsMultiIf" ppr_one (h:t) = hang h 2 (sep t) one_alt = [ interpp'SP guards , text "->" <+> pprDeeper (ppr expr) ] ppr_alt (L _ (XGRHS x)) = ppr x -- special case: let ... in let ... ppr_expr (HsLet _ _ binds _ expr@(L _ (HsLet _ _ _ _ _))) = sep [hang (text "let") 2 (hsep [pprBinds binds, text "in"]), ppr_lexpr expr] ppr_expr (HsLet _ _ binds _ expr) = sep [hang (text "let") 2 (pprBinds binds), hang (text "in") 2 (ppr expr)] ppr_expr (HsDo _ do_or_list_comp (L _ stmts)) = pprDo do_or_list_comp stmts ppr_expr (ExplicitList _ exprs) = brackets (pprDeeperList fsep (punctuate comma (map ppr_lexpr exprs))) ppr_expr (RecordCon { rcon_con = con, rcon_flds = rbinds }) = hang pp_con 2 (ppr rbinds) where -- con :: ConLikeP (GhcPass p) -- so we need case analysis to know to print it pp_con = case ghcPass @p of GhcPs -> ppr con GhcRn -> ppr con GhcTc -> ppr con ppr_expr (RecordUpd { rupd_expr = L _ aexp, rupd_flds = flds }) = case flds of Left rbinds -> hang (ppr aexp) 2 (braces (fsep (punctuate comma (map ppr rbinds)))) Right pbinds -> hang (ppr aexp) 2 (braces (fsep (punctuate comma (map ppr pbinds)))) ppr_expr (HsGetField { gf_expr = L _ fexp, gf_field = field }) = ppr fexp <> dot <> ppr field ppr_expr (HsProjection { proj_flds = flds }) = parens (hcat (dot : (punctuate dot (map ppr $ toList flds)))) ppr_expr (ExprWithTySig _ expr sig) = hang (nest 2 (ppr_lexpr expr) <+> dcolon) 4 (ppr sig) ppr_expr (ArithSeq _ _ info) = brackets (ppr info) ppr_expr (HsSpliceE _ s) = pprSplice s ppr_expr (HsTypedBracket b e) = case ghcPass @p of GhcPs -> thTyBrackets (ppr e) GhcRn -> thTyBrackets (ppr e) GhcTc | HsBracketTc _ _ty _wrap ps <- b -> thTyBrackets (ppr e) `ppr_with_pending_tc_splices` ps ppr_expr (HsUntypedBracket b q) = case ghcPass @p of GhcPs -> ppr q GhcRn -> case b of [] -> ppr q ps -> ppr q $$ text "pending(rn)" <+> ppr ps GhcTc | HsBracketTc rnq _ty _wrap ps <- b -> ppr rnq `ppr_with_pending_tc_splices` ps ppr_expr (HsProc _ pat (L _ (HsCmdTop _ cmd))) = hsep [text "proc", ppr pat, text "->", ppr cmd] ppr_expr (HsStatic _ e) = hsep [text "static", ppr e] ppr_expr (XExpr x) = case ghcPass @p of #if __GLASGOW_HASKELL__ < 811 GhcPs -> ppr x #endif GhcRn -> ppr x GhcTc -> ppr x instance Outputable XXExprGhcTc where ppr (WrapExpr (HsWrap co_fn e)) = pprHsWrapper co_fn (\_parens -> pprExpr e) ppr (ExpansionExpr e) = ppr e -- e is an HsExpansion, we print the original -- expression (LHsExpr GhcPs), not the -- desugared one (LHsExpr GhcTc). ppr (ConLikeTc con _ _) = pprPrefixOcc con -- Used in error messages generated by -- the pattern match overlap checker ppr (HsTick tickish exp) = pprTicks (ppr exp) $ ppr tickish <+> ppr_lexpr exp ppr (HsBinTick tickIdTrue tickIdFalse exp) = pprTicks (ppr exp) $ hcat [text "bintick<", ppr tickIdTrue, text ",", ppr tickIdFalse, text ">(", ppr exp, text ")"] ppr_infix_expr :: forall p. (OutputableBndrId p) => HsExpr (GhcPass p) -> Maybe SDoc ppr_infix_expr (HsVar _ (L _ v)) = Just (pprInfixOcc v) ppr_infix_expr (HsRecSel _ f) = Just (pprInfixOcc f) ppr_infix_expr (HsUnboundVar _ occ) = Just (pprInfixOcc occ) ppr_infix_expr (XExpr x) = case ghcPass @p of #if __GLASGOW_HASKELL__ < 901 GhcPs -> Nothing #endif GhcRn -> ppr_infix_expr_rn x GhcTc -> ppr_infix_expr_tc x ppr_infix_expr _ = Nothing ppr_infix_expr_rn :: HsExpansion (HsExpr GhcRn) (HsExpr GhcRn) -> Maybe SDoc ppr_infix_expr_rn (HsExpanded a _) = ppr_infix_expr a ppr_infix_expr_tc :: XXExprGhcTc -> Maybe SDoc ppr_infix_expr_tc (WrapExpr (HsWrap _ e)) = ppr_infix_expr e ppr_infix_expr_tc (ExpansionExpr (HsExpanded a _)) = ppr_infix_expr a ppr_infix_expr_tc (ConLikeTc {}) = Nothing ppr_infix_expr_tc (HsTick {}) = Nothing ppr_infix_expr_tc (HsBinTick {}) = Nothing ppr_apps :: (OutputableBndrId p) => HsExpr (GhcPass p) -> [Either (LHsExpr (GhcPass p)) (LHsWcType (NoGhcTc (GhcPass p)))] -> SDoc ppr_apps (HsApp _ (L _ fun) arg) args = ppr_apps fun (Left arg : args) ppr_apps (HsAppType _ (L _ fun) arg) args = ppr_apps fun (Right arg : args) ppr_apps fun args = hang (ppr_expr fun) 2 (fsep (map pp args)) where pp (Left arg) = ppr arg -- pp (Right (LHsWcTypeX (HsWC { hswc_body = L _ arg }))) -- = char '@' <> pprHsType arg pp (Right arg) = text "@" <> ppr arg pprDebugParendExpr :: (OutputableBndrId p) => PprPrec -> LHsExpr (GhcPass p) -> SDoc pprDebugParendExpr p expr = getPprDebug $ \case True -> pprParendLExpr p expr False -> pprLExpr expr pprParendLExpr :: (OutputableBndrId p) => PprPrec -> LHsExpr (GhcPass p) -> SDoc pprParendLExpr p (L _ e) = pprParendExpr p e pprParendExpr :: (OutputableBndrId p) => PprPrec -> HsExpr (GhcPass p) -> SDoc pprParendExpr p expr | hsExprNeedsParens p expr = parens (pprExpr expr) | otherwise = pprExpr expr -- Using pprLExpr makes sure that we go 'deeper' -- I think that is usually (always?) right -- | @'hsExprNeedsParens' p e@ returns 'True' if the expression @e@ needs -- parentheses under precedence @p@. hsExprNeedsParens :: forall p. IsPass p => PprPrec -> HsExpr (GhcPass p) -> Bool hsExprNeedsParens prec = go where go :: HsExpr (GhcPass p) -> Bool go (HsVar{}) = False go (HsUnboundVar{}) = False go (HsIPVar{}) = False go (HsOverLabel{}) = False go (HsLit _ l) = hsLitNeedsParens prec l go (HsOverLit _ ol) = hsOverLitNeedsParens prec ol go (HsPar{}) = False go (HsApp{}) = prec >= appPrec go (HsAppType {}) = prec >= appPrec go (OpApp{}) = prec >= opPrec go (NegApp{}) = prec > topPrec go (SectionL{}) = True go (SectionR{}) = True -- Special-case unary boxed tuple applications so that they are -- parenthesized as `Identity (Solo x)`, not `Identity Solo x` (#18612) -- See Note [One-tuples] in GHC.Builtin.Types go (ExplicitTuple _ [Present{}] Boxed) = prec >= appPrec go (ExplicitTuple{}) = False go (ExplicitSum{}) = False go (HsLam{}) = prec > topPrec go (HsLamCase{}) = prec > topPrec go (HsCase{}) = prec > topPrec go (HsIf{}) = prec > topPrec go (HsMultiIf{}) = prec > topPrec go (HsLet{}) = prec > topPrec go (HsDo _ sc _) | isDoComprehensionContext sc = False | otherwise = prec > topPrec go (ExplicitList{}) = False go (RecordUpd{}) = False go (ExprWithTySig{}) = prec >= sigPrec go (ArithSeq{}) = False go (HsPragE{}) = prec >= appPrec go (HsSpliceE{}) = False go (HsTypedBracket{}) = False go (HsUntypedBracket{}) = False go (HsProc{}) = prec > topPrec go (HsStatic{}) = prec >= appPrec go (RecordCon{}) = False go (HsRecSel{}) = False go (HsProjection{}) = True go (HsGetField{}) = False go (XExpr x) = case ghcPass @p of GhcTc -> go_x_tc x GhcRn -> go_x_rn x #if __GLASGOW_HASKELL__ <= 900 GhcPs -> True #endif go_x_tc :: XXExprGhcTc -> Bool go_x_tc (WrapExpr (HsWrap _ e)) = hsExprNeedsParens prec e go_x_tc (ExpansionExpr (HsExpanded a _)) = hsExprNeedsParens prec a go_x_tc (ConLikeTc {}) = False go_x_tc (HsTick _ (L _ e)) = hsExprNeedsParens prec e go_x_tc (HsBinTick _ _ (L _ e)) = hsExprNeedsParens prec e go_x_rn :: HsExpansion (HsExpr GhcRn) (HsExpr GhcRn) -> Bool go_x_rn (HsExpanded a _) = hsExprNeedsParens prec a -- | Parenthesize an expression without token information gHsPar :: LHsExpr (GhcPass id) -> HsExpr (GhcPass id) gHsPar e = HsPar noAnn noHsTok e noHsTok -- | @'parenthesizeHsExpr' p e@ checks if @'hsExprNeedsParens' p e@ is true, -- and if so, surrounds @e@ with an 'HsPar'. Otherwise, it simply returns @e@. parenthesizeHsExpr :: IsPass p => PprPrec -> LHsExpr (GhcPass p) -> LHsExpr (GhcPass p) parenthesizeHsExpr p le@(L loc e) | hsExprNeedsParens p e = L loc (gHsPar le) | otherwise = le stripParensLHsExpr :: LHsExpr (GhcPass p) -> LHsExpr (GhcPass p) stripParensLHsExpr (L _ (HsPar _ _ e _)) = stripParensLHsExpr e stripParensLHsExpr e = e stripParensHsExpr :: HsExpr (GhcPass p) -> HsExpr (GhcPass p) stripParensHsExpr (HsPar _ _ (L _ e) _) = stripParensHsExpr e stripParensHsExpr e = e isAtomicHsExpr :: forall p. IsPass p => HsExpr (GhcPass p) -> Bool -- True of a single token isAtomicHsExpr (HsVar {}) = True isAtomicHsExpr (HsLit {}) = True isAtomicHsExpr (HsOverLit {}) = True isAtomicHsExpr (HsIPVar {}) = True isAtomicHsExpr (HsOverLabel {}) = True isAtomicHsExpr (HsUnboundVar {}) = True isAtomicHsExpr (HsRecSel{}) = True isAtomicHsExpr (XExpr x) | GhcTc <- ghcPass @p = go_x_tc x | GhcRn <- ghcPass @p = go_x_rn x where go_x_tc (WrapExpr (HsWrap _ e)) = isAtomicHsExpr e go_x_tc (ExpansionExpr (HsExpanded a _)) = isAtomicHsExpr a go_x_tc (ConLikeTc {}) = True go_x_tc (HsTick {}) = False go_x_tc (HsBinTick {}) = False go_x_rn (HsExpanded a _) = isAtomicHsExpr a isAtomicHsExpr _ = False instance Outputable (HsPragE (GhcPass p)) where ppr (HsPragSCC _ st (StringLiteral stl lbl _)) = pprWithSourceText st (text "{-# SCC") -- no doublequotes if stl empty, for the case where the SCC was written -- without quotes. <+> pprWithSourceText stl (ftext lbl) <+> text "#-}" {- ********************************************************************* * * HsExpansion and rebindable syntax * * ********************************************************************* -} {- Note [Rebindable syntax and HsExpansion] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We implement rebindable syntax (RS) support by performing a desugaring in the renamer. We transform GhcPs expressions and patterns affected by RS into the appropriate desugared form, but **annotated with the original expression/pattern**. Let us consider a piece of code like: {-# LANGUAGE RebindableSyntax #-} ifThenElse :: Char -> () -> () -> () ifThenElse _ _ _ = () x = if 'a' then () else True The parsed AST for the RHS of x would look something like (slightly simplified): L locif (HsIf (L loca 'a') (L loctrue ()) (L locfalse True)) Upon seeing such an AST with RS on, we could transform it into a mere function call, as per the RS rules, equivalent to the following function application: ifThenElse 'a' () True which doesn't typecheck. But GHC would report an error about not being able to match the third argument's type (Bool) with the expected type: (), in the expression _as desugared_, i.e in the aforementioned function application. But the user never wrote a function application! This would be pretty bad. To remedy this, instead of transforming the original HsIf node into mere applications of 'ifThenElse', we keep the original 'if' expression around too, using the TTG XExpr extension point to allow GHC to construct an 'HsExpansion' value that will keep track of the original expression in its first field, and the desugared one in the second field. The resulting renamed AST would look like: L locif (XExpr (HsExpanded (HsIf (L loca 'a') (L loctrue ()) (L locfalse True) ) (App (L generatedSrcSpan (App (L generatedSrcSpan (App (L generatedSrcSpan (Var ifThenElse)) (L loca 'a') ) ) (L loctrue ()) ) ) (L locfalse True) ) ) ) When comes the time to typecheck the program, we end up calling tcMonoExpr on the AST above. If this expression gives rise to a type error, then it will appear in a context line and GHC will pretty-print it using the 'Outputable (HsExpansion a b)' instance defined below, which *only prints the original expression*. This is the gist of the idea, but is not quite enough to recover the error messages that we had with the SyntaxExpr-based, typechecking/desugaring-to-core time implementation of rebindable syntax. The key idea is to decorate some elements of the desugared expression so as to be able to give them a special treatment when typechecking the desugared expression, to print a different context line or skip one altogether. Whenever we 'setSrcSpan' a 'generatedSrcSpan', we update a field in TcLclEnv called 'tcl_in_gen_code', setting it to True, which indicates that we entered generated code, i.e code fabricated by the compiler when rebinding some syntax. If someone tries to push some error context line while that field is set to True, the pushing won't actually happen and the context line is just dropped. Once we 'setSrcSpan' a real span (for an expression that was in the original source code), we set 'tcl_in_gen_code' back to False, indicating that we "emerged from the generated code tunnel", and that the expressions we will be processing are relevant to report in context lines again. You might wonder why TcLclEnv has both tcl_loc :: RealSrcSpan tcl_in_gen_code :: Bool Could we not store a Maybe RealSrcSpan? The problem is that we still generate constraints when processing generated code, and a CtLoc must contain a RealSrcSpan -- otherwise, error messages might appear without source locations. So tcl_loc keeps the RealSrcSpan of the last location spotted that wasn't generated; it's as good as we're going to get in generated code. Once we get to sub-trees that are not generated, then we update the RealSrcSpan appropriately, and set the tcl_in_gen_code Bool to False. --- An overview of the constructs that are desugared in this way is laid out in Note [Handling overloaded and rebindable constructs] in GHC.Rename.Expr. A general recipe to follow this approach for new constructs could go as follows: - Remove any GhcRn-time SyntaxExpr extensions to the relevant constructor for your construct, in HsExpr or related syntax data types. - At renaming-time: - take your original node of interest (HsIf above) - rename its subexpressions/subpatterns (condition and true/false branches above) - construct the suitable "rebound"-and-renamed result (ifThenElse call above), where the 'SrcSpan' attached to any _fabricated node_ (the HsVar/HsApp nodes, above) is set to 'generatedSrcSpan' - take both the original node and that rebound-and-renamed result and wrap them into an expansion construct: for expressions, XExpr (HsExpanded ) for patterns, XPat (HsPatExpanded ) - At typechecking-time: - remove any logic that was previously dealing with your rebindable construct, typically involving [tc]SyntaxOp, SyntaxExpr and friends. - the XExpr (HsExpanded ... ...) case in tcExpr already makes sure that we typecheck the desugared expression while reporting the original one in errors -} {- Note [Overview of record dot syntax] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This is the note that explains all the moving parts for record dot syntax. The language extensions @OverloadedRecordDot@ and @OverloadedRecordUpdate@ (providing "record dot syntax") are implemented using the techniques of Note [Rebindable syntax and HsExpansion]. When OverloadedRecordDot is enabled: - Field selection expressions - e.g. foo.bar.baz - Have abstract syntax HsGetField - After renaming are XExpr (HsExpanded (HsGetField ...) (getField @"..."...)) expressions - Field selector expressions e.g. (.x.y) - Have abstract syntax HsProjection - After renaming are XExpr (HsExpanded (HsProjection ...) ((getField @"...") . (getField @"...") . ...) expressions When OverloadedRecordUpdate is enabled: - Record update expressions - e.g. a{foo.bar=1, quux="corge", baz} - Have abstract syntax RecordUpd - With rupd_flds containting a Right - See Note [RecordDotSyntax field updates] (in Language.Haskell.Syntax.Expr) - After renaming are XExpr (HsExpanded (RecordUpd ...) (setField@"..." ...) expressions - Note that this is true for all record updates even for those that do not involve '.' When OverloadedRecordDot is enabled and RebindableSyntax is not enabled the name 'getField' is resolved to GHC.Records.getField. When OverloadedRecordDot is enabled and RebindableSyntax is enabled the name 'getField' is whatever in-scope name that is. When OverloadedRecordUpd is enabled and RebindableSyntax is not enabled it is an error for now (temporary while we wait on native setField support; see https://gitlab.haskell.org/ghc/ghc/-/issues/16232). When OverloadedRecordUpd is enabled and RebindableSyntax is enabled the names 'getField' and 'setField' are whatever in-scope names they are. -} -- See Note [Rebindable syntax and HsExpansion] just above. data HsExpansion orig expanded = HsExpanded orig expanded deriving Data -- | Just print the original expression (the @a@). instance (Outputable a, Outputable b) => Outputable (HsExpansion a b) where ppr (HsExpanded orig expanded) = ifPprDebug (vcat [ppr orig, braces (text "Expansion:" <+> ppr expanded)]) (ppr orig) {- ************************************************************************ * * \subsection{Commands (in arrow abstractions)} * * ************************************************************************ -} type instance XCmdArrApp GhcPs = EpAnn AddEpAnn type instance XCmdArrApp GhcRn = NoExtField type instance XCmdArrApp GhcTc = Type type instance XCmdArrForm GhcPs = EpAnn AnnList type instance XCmdArrForm GhcRn = NoExtField type instance XCmdArrForm GhcTc = NoExtField type instance XCmdApp (GhcPass _) = EpAnnCO type instance XCmdLam (GhcPass _) = NoExtField type instance XCmdPar (GhcPass _) = EpAnnCO type instance XCmdCase GhcPs = EpAnn EpAnnHsCase type instance XCmdCase GhcRn = NoExtField type instance XCmdCase GhcTc = NoExtField type instance XCmdLamCase (GhcPass _) = EpAnn [AddEpAnn] type instance XCmdIf GhcPs = EpAnn AnnsIf type instance XCmdIf GhcRn = NoExtField type instance XCmdIf GhcTc = NoExtField type instance XCmdLet GhcPs = EpAnnCO type instance XCmdLet GhcRn = NoExtField type instance XCmdLet GhcTc = NoExtField type instance XCmdDo GhcPs = EpAnn AnnList type instance XCmdDo GhcRn = NoExtField type instance XCmdDo GhcTc = Type type instance XCmdWrap (GhcPass _) = NoExtField type instance XXCmd GhcPs = DataConCantHappen type instance XXCmd GhcRn = DataConCantHappen type instance XXCmd GhcTc = HsWrap HsCmd type instance Anno [LocatedA (StmtLR (GhcPass pl) (GhcPass pr) (LocatedA (HsCmd (GhcPass pr))))] = SrcSpanAnnL -- If cmd :: arg1 --> res -- wrap :: arg1 "->" arg2 -- Then (XCmd (HsWrap wrap cmd)) :: arg2 --> res data CmdTopTc = CmdTopTc Type -- Nested tuple of inputs on the command's stack Type -- return type of the command (CmdSyntaxTable GhcTc) -- See Note [CmdSyntaxTable] type instance XCmdTop GhcPs = NoExtField type instance XCmdTop GhcRn = CmdSyntaxTable GhcRn -- See Note [CmdSyntaxTable] type instance XCmdTop GhcTc = CmdTopTc type instance XXCmdTop (GhcPass _) = DataConCantHappen instance (OutputableBndrId p) => Outputable (HsCmd (GhcPass p)) where ppr cmd = pprCmd cmd ----------------------- -- pprCmd and pprLCmd call pprDeeper; -- the underscore versions do not pprLCmd :: (OutputableBndrId p) => LHsCmd (GhcPass p) -> SDoc pprLCmd (L _ c) = pprCmd c pprCmd :: (OutputableBndrId p) => HsCmd (GhcPass p) -> SDoc pprCmd c | isQuietHsCmd c = ppr_cmd c | otherwise = pprDeeper (ppr_cmd c) isQuietHsCmd :: HsCmd id -> Bool -- Parentheses do display something, but it gives little info and -- if we go deeper when we go inside them then we get ugly things -- like (...) isQuietHsCmd (HsCmdPar {}) = True -- applications don't display anything themselves isQuietHsCmd (HsCmdApp {}) = True isQuietHsCmd _ = False ----------------------- ppr_lcmd :: (OutputableBndrId p) => LHsCmd (GhcPass p) -> SDoc ppr_lcmd c = ppr_cmd (unLoc c) ppr_cmd :: forall p. (OutputableBndrId p ) => HsCmd (GhcPass p) -> SDoc ppr_cmd (HsCmdPar _ _ c _) = parens (ppr_lcmd c) ppr_cmd (HsCmdApp _ c e) = let (fun, args) = collect_args c [e] in hang (ppr_lcmd fun) 2 (sep (map ppr args)) where collect_args (L _ (HsCmdApp _ fun arg)) args = collect_args fun (arg:args) collect_args fun args = (fun, args) ppr_cmd (HsCmdLam _ matches) = pprMatches matches ppr_cmd (HsCmdCase _ expr matches) = sep [ sep [text "case", nest 4 (ppr expr), text "of"], nest 2 (pprMatches matches) ] ppr_cmd (HsCmdLamCase _ lc_variant matches) = sep [ lamCaseKeyword lc_variant, nest 2 (pprMatches matches) ] ppr_cmd (HsCmdIf _ _ e ct ce) = sep [hsep [text "if", nest 2 (ppr e), text "then"], nest 4 (ppr ct), text "else", nest 4 (ppr ce)] -- special case: let ... in let ... ppr_cmd (HsCmdLet _ _ binds _ cmd@(L _ (HsCmdLet {}))) = sep [hang (text "let") 2 (hsep [pprBinds binds, text "in"]), ppr_lcmd cmd] ppr_cmd (HsCmdLet _ _ binds _ cmd) = sep [hang (text "let") 2 (pprBinds binds), hang (text "in") 2 (ppr cmd)] ppr_cmd (HsCmdDo _ (L _ stmts)) = pprArrowExpr stmts ppr_cmd (HsCmdArrApp _ arrow arg HsFirstOrderApp True) = hsep [ppr_lexpr arrow, larrowt, ppr_lexpr arg] ppr_cmd (HsCmdArrApp _ arrow arg HsFirstOrderApp False) = hsep [ppr_lexpr arg, arrowt, ppr_lexpr arrow] ppr_cmd (HsCmdArrApp _ arrow arg HsHigherOrderApp True) = hsep [ppr_lexpr arrow, larrowtt, ppr_lexpr arg] ppr_cmd (HsCmdArrApp _ arrow arg HsHigherOrderApp False) = hsep [ppr_lexpr arg, arrowtt, ppr_lexpr arrow] ppr_cmd (HsCmdArrForm _ (L _ op) ps_fix rn_fix args) | HsVar _ (L _ v) <- op = ppr_cmd_infix v | GhcTc <- ghcPass @p , XExpr (ConLikeTc c _ _) <- op = ppr_cmd_infix (conLikeName c) | otherwise = fall_through where fall_through = hang (text "(|" <+> ppr_expr op) 4 (sep (map (pprCmdArg.unLoc) args) <+> text "|)") ppr_cmd_infix :: OutputableBndr v => v -> SDoc ppr_cmd_infix v | [arg1, arg2] <- args , isJust rn_fix || ps_fix == Infix = hang (pprCmdArg (unLoc arg1)) 4 (sep [ pprInfixOcc v, pprCmdArg (unLoc arg2)]) | otherwise = fall_through ppr_cmd (XCmd x) = case ghcPass @p of #if __GLASGOW_HASKELL__ < 811 GhcPs -> ppr x GhcRn -> ppr x #endif GhcTc -> case x of HsWrap w cmd -> pprHsWrapper w (\_ -> parens (ppr_cmd cmd)) pprCmdArg :: (OutputableBndrId p) => HsCmdTop (GhcPass p) -> SDoc pprCmdArg (HsCmdTop _ cmd) = ppr_lcmd cmd instance (OutputableBndrId p) => Outputable (HsCmdTop (GhcPass p)) where ppr = pprCmdArg {- ************************************************************************ * * \subsection{@Match@, @GRHSs@, and @GRHS@ datatypes} * * ************************************************************************ -} type instance XMG GhcPs b = NoExtField type instance XMG GhcRn b = NoExtField type instance XMG GhcTc b = MatchGroupTc type instance XXMatchGroup (GhcPass _) b = DataConCantHappen type instance XCMatch (GhcPass _) b = EpAnn [AddEpAnn] type instance XXMatch (GhcPass _) b = DataConCantHappen instance (OutputableBndrId pr, Outputable body) => Outputable (Match (GhcPass pr) body) where ppr = pprMatch isEmptyMatchGroup :: MatchGroup (GhcPass p) body -> Bool isEmptyMatchGroup (MG { mg_alts = ms }) = null $ unLoc ms -- | Is there only one RHS in this list of matches? isSingletonMatchGroup :: [LMatch (GhcPass p) body] -> Bool isSingletonMatchGroup matches | [L _ match] <- matches , Match { m_grhss = GRHSs { grhssGRHSs = [_] } } <- match = True | otherwise = False matchGroupArity :: MatchGroup (GhcPass id) body -> Arity -- Precondition: MatchGroup is non-empty -- This is called before type checking, when mg_arg_tys is not set matchGroupArity (MG { mg_alts = alts }) | L _ (alt1:_) <- alts = length (hsLMatchPats alt1) | otherwise = panic "matchGroupArity" hsLMatchPats :: LMatch (GhcPass id) body -> [LPat (GhcPass id)] hsLMatchPats (L _ (Match { m_pats = pats })) = pats -- We keep the type checker happy by providing EpAnnComments. They -- can only be used if they follow a `where` keyword with no binds, -- but in that case the comment is attached to the following parsed -- item. So this can never be used in practice. type instance XCGRHSs (GhcPass _) _ = EpAnnComments type instance XXGRHSs (GhcPass _) _ = DataConCantHappen data GrhsAnn = GrhsAnn { ga_vbar :: Maybe EpaLocation, -- TODO:AZ do we need this? ga_sep :: AddEpAnn -- ^ Match separator location } deriving (Data) type instance XCGRHS (GhcPass _) _ = EpAnn GrhsAnn -- Location of matchSeparator -- TODO:AZ does this belong on the GRHS, or GRHSs? type instance XXGRHS (GhcPass _) b = DataConCantHappen pprMatches :: (OutputableBndrId idR, Outputable body) => MatchGroup (GhcPass idR) body -> SDoc pprMatches MG { mg_alts = matches } = vcat (map pprMatch (map unLoc (unLoc matches))) -- Don't print the type; it's only a place-holder before typechecking -- Exported to GHC.Hs.Binds, which can't see the defn of HsMatchContext pprFunBind :: (OutputableBndrId idR) => MatchGroup (GhcPass idR) (LHsExpr (GhcPass idR)) -> SDoc pprFunBind matches = pprMatches matches -- Exported to GHC.Hs.Binds, which can't see the defn of HsMatchContext pprPatBind :: forall bndr p . (OutputableBndrId bndr, OutputableBndrId p) => LPat (GhcPass bndr) -> GRHSs (GhcPass p) (LHsExpr (GhcPass p)) -> SDoc pprPatBind pat grhss = sep [ppr pat, nest 2 (pprGRHSs (PatBindRhs :: HsMatchContext (GhcPass p)) grhss)] pprMatch :: (OutputableBndrId idR, Outputable body) => Match (GhcPass idR) body -> SDoc pprMatch (Match { m_pats = pats, m_ctxt = ctxt, m_grhss = grhss }) = sep [ sep (herald : map (nest 2 . pprParendLPat appPrec) other_pats) , nest 2 (pprGRHSs ctxt grhss) ] where (herald, other_pats) = case ctxt of FunRhs {mc_fun=L _ fun, mc_fixity=fixity, mc_strictness=strictness} | SrcStrict <- strictness -> assert (null pats) -- A strict variable binding (char '!'<>pprPrefixOcc fun, pats) | Prefix <- fixity -> (pprPrefixOcc fun, pats) -- f x y z = e -- Not pprBndr; the AbsBinds will -- have printed the signature | otherwise -> case pats of (p1:p2:rest) | null rest -> (pp_infix, []) -- x &&& y = e | otherwise -> (parens pp_infix, rest) -- (x &&& y) z = e where pp_infix = pprParendLPat opPrec p1 <+> pprInfixOcc fun <+> pprParendLPat opPrec p2 _ -> pprPanic "pprMatch" (ppr ctxt $$ ppr pats) LambdaExpr -> (char '\\', pats) -- We don't simply return (empty, pats) to avoid introducing an -- additional `nest 2` via the empty herald LamCaseAlt LamCases -> maybe (empty, []) (first $ pprParendLPat appPrec) (uncons pats) ArrowMatchCtxt (ArrowLamCaseAlt LamCases) -> maybe (empty, []) (first $ pprParendLPat appPrec) (uncons pats) ArrowMatchCtxt KappaExpr -> (char '\\', pats) ArrowMatchCtxt ProcExpr -> (text "proc", pats) _ -> case pats of [] -> (empty, []) [pat] -> (ppr pat, []) -- No parens around the single pat in a case _ -> pprPanic "pprMatch" (ppr ctxt $$ ppr pats) pprGRHSs :: (OutputableBndrId idR, Outputable body) => HsMatchContext passL -> GRHSs (GhcPass idR) body -> SDoc pprGRHSs ctxt (GRHSs _ grhss binds) = vcat (map (pprGRHS ctxt . unLoc) grhss) -- Print the "where" even if the contents of the binds is empty. Only -- EmptyLocalBinds means no "where" keyword $$ ppUnless (eqEmptyLocalBinds binds) (text "where" $$ nest 4 (pprBinds binds)) pprGRHS :: (OutputableBndrId idR, Outputable body) => HsMatchContext passL -> GRHS (GhcPass idR) body -> SDoc pprGRHS ctxt (GRHS _ [] body) = pp_rhs ctxt body pprGRHS ctxt (GRHS _ guards body) = sep [vbar <+> interpp'SP guards, pp_rhs ctxt body] pp_rhs :: Outputable body => HsMatchContext passL -> body -> SDoc pp_rhs ctxt rhs = matchSeparator ctxt <+> pprDeeper (ppr rhs) instance Outputable GrhsAnn where ppr (GrhsAnn v s) = text "GrhsAnn" <+> ppr v <+> ppr s {- ************************************************************************ * * \subsection{Do stmts and list comprehensions} * * ************************************************************************ -} -- Extra fields available post typechecking for RecStmt. data RecStmtTc = RecStmtTc { recS_bind_ty :: Type -- S in (>>=) :: Q -> (R -> S) -> T , recS_later_rets :: [PostTcExpr] -- (only used in the arrow version) , recS_rec_rets :: [PostTcExpr] -- These expressions correspond 1-to-1 -- with recS_later_ids and recS_rec_ids, -- and are the expressions that should be -- returned by the recursion. -- They may not quite be the Ids themselves, -- because the Id may be *polymorphic*, but -- the returned thing has to be *monomorphic*, -- so they may be type applications , recS_ret_ty :: Type -- The type of -- do { stmts; return (a,b,c) } -- With rebindable syntax the type might not -- be quite as simple as (m (tya, tyb, tyc)). } type instance XLastStmt (GhcPass _) (GhcPass _) b = NoExtField type instance XBindStmt (GhcPass _) GhcPs b = EpAnn [AddEpAnn] type instance XBindStmt (GhcPass _) GhcRn b = XBindStmtRn type instance XBindStmt (GhcPass _) GhcTc b = XBindStmtTc data XBindStmtRn = XBindStmtRn { xbsrn_bindOp :: SyntaxExpr GhcRn , xbsrn_failOp :: FailOperator GhcRn } data XBindStmtTc = XBindStmtTc { xbstc_bindOp :: SyntaxExpr GhcTc , xbstc_boundResultType :: Type -- If (>>=) :: Q -> (R -> S) -> T, this is S , xbstc_boundResultMult :: Mult -- If (>>=) :: Q -> (R -> S) -> T, this is S , xbstc_failOp :: FailOperator GhcTc } type instance XApplicativeStmt (GhcPass _) GhcPs b = NoExtField type instance XApplicativeStmt (GhcPass _) GhcRn b = NoExtField type instance XApplicativeStmt (GhcPass _) GhcTc b = Type type instance XBodyStmt (GhcPass _) GhcPs b = NoExtField type instance XBodyStmt (GhcPass _) GhcRn b = NoExtField type instance XBodyStmt (GhcPass _) GhcTc b = Type type instance XLetStmt (GhcPass _) (GhcPass _) b = EpAnn [AddEpAnn] type instance XParStmt (GhcPass _) GhcPs b = NoExtField type instance XParStmt (GhcPass _) GhcRn b = NoExtField type instance XParStmt (GhcPass _) GhcTc b = Type type instance XTransStmt (GhcPass _) GhcPs b = EpAnn [AddEpAnn] type instance XTransStmt (GhcPass _) GhcRn b = NoExtField type instance XTransStmt (GhcPass _) GhcTc b = Type type instance XRecStmt (GhcPass _) GhcPs b = EpAnn AnnList type instance XRecStmt (GhcPass _) GhcRn b = NoExtField type instance XRecStmt (GhcPass _) GhcTc b = RecStmtTc type instance XXStmtLR (GhcPass _) (GhcPass _) b = DataConCantHappen type instance XParStmtBlock (GhcPass pL) (GhcPass pR) = NoExtField type instance XXParStmtBlock (GhcPass pL) (GhcPass pR) = DataConCantHappen type instance XApplicativeArgOne GhcPs = NoExtField type instance XApplicativeArgOne GhcRn = FailOperator GhcRn type instance XApplicativeArgOne GhcTc = FailOperator GhcTc type instance XApplicativeArgMany (GhcPass _) = NoExtField type instance XXApplicativeArg (GhcPass _) = DataConCantHappen instance (Outputable (StmtLR (GhcPass idL) (GhcPass idL) (LHsExpr (GhcPass idL))), Outputable (XXParStmtBlock (GhcPass idL) (GhcPass idR))) => Outputable (ParStmtBlock (GhcPass idL) (GhcPass idR)) where ppr (ParStmtBlock _ stmts _ _) = interpp'SP stmts instance (OutputableBndrId pl, OutputableBndrId pr, Anno (StmtLR (GhcPass pl) (GhcPass pr) body) ~ SrcSpanAnnA, Outputable body) => Outputable (StmtLR (GhcPass pl) (GhcPass pr) body) where ppr stmt = pprStmt stmt pprStmt :: forall idL idR body . (OutputableBndrId idL, OutputableBndrId idR, Anno (StmtLR (GhcPass idL) (GhcPass idR) body) ~ SrcSpanAnnA, Outputable body) => (StmtLR (GhcPass idL) (GhcPass idR) body) -> SDoc pprStmt (LastStmt _ expr m_dollar_stripped _) = whenPprDebug (text "[last]") <+> (case m_dollar_stripped of Just True -> text "return $" Just False -> text "return" Nothing -> empty) <+> ppr expr pprStmt (BindStmt _ pat expr) = pprBindStmt pat expr pprStmt (LetStmt _ binds) = hsep [text "let", pprBinds binds] pprStmt (BodyStmt _ expr _ _) = ppr expr pprStmt (ParStmt _ stmtss _ _) = sep (punctuate (text " | ") (map ppr stmtss)) pprStmt (TransStmt { trS_stmts = stmts, trS_by = by , trS_using = using, trS_form = form }) = sep $ punctuate comma (map ppr stmts ++ [pprTransStmt by using form]) pprStmt (RecStmt { recS_stmts = segment, recS_rec_ids = rec_ids , recS_later_ids = later_ids }) = text "rec" <+> vcat [ ppr_do_stmts (unLoc segment) , whenPprDebug (vcat [ text "rec_ids=" <> ppr rec_ids , text "later_ids=" <> ppr later_ids])] pprStmt (ApplicativeStmt _ args mb_join) = getPprStyle $ \style -> if userStyle style then pp_for_user else pp_debug where -- make all the Applicative stuff invisible in error messages by -- flattening the whole ApplicativeStmt nest back to a sequence -- of statements. pp_for_user = vcat $ concatMap flattenArg args -- ppr directly rather than transforming here, because we need to -- inject a "return" which is hard when we're polymorphic in the id -- type. flattenStmt :: ExprLStmt (GhcPass idL) -> [SDoc] flattenStmt (L _ (ApplicativeStmt _ args _)) = concatMap flattenArg args flattenStmt stmt = [ppr stmt] flattenArg :: forall a . (a, ApplicativeArg (GhcPass idL)) -> [SDoc] flattenArg (_, ApplicativeArgOne _ pat expr isBody) | isBody = [ppr expr] -- See Note [Applicative BodyStmt] | otherwise = [pprBindStmt pat expr] flattenArg (_, ApplicativeArgMany _ stmts _ _ _) = concatMap flattenStmt stmts pp_debug = let ap_expr = sep (punctuate (text " |") (map pp_arg args)) in whenPprDebug (if isJust mb_join then text "[join]" else empty) <+> (if lengthAtLeast args 2 then parens else id) ap_expr pp_arg :: (a, ApplicativeArg (GhcPass idL)) -> SDoc pp_arg (_, applicativeArg) = ppr applicativeArg pprBindStmt :: (Outputable pat, Outputable expr) => pat -> expr -> SDoc pprBindStmt pat expr = hsep [ppr pat, larrow, ppr expr] instance (OutputableBndrId idL) => Outputable (ApplicativeArg (GhcPass idL)) where ppr = pprArg pprArg :: forall idL . (OutputableBndrId idL) => ApplicativeArg (GhcPass idL) -> SDoc pprArg (ApplicativeArgOne _ pat expr isBody) | isBody = ppr expr -- See Note [Applicative BodyStmt] | otherwise = pprBindStmt pat expr pprArg (ApplicativeArgMany _ stmts return pat ctxt) = ppr pat <+> text "<-" <+> pprDo ctxt (stmts ++ [noLocA (LastStmt noExtField (noLocA return) Nothing noSyntaxExpr)]) pprTransformStmt :: (OutputableBndrId p) => [IdP (GhcPass p)] -> LHsExpr (GhcPass p) -> Maybe (LHsExpr (GhcPass p)) -> SDoc pprTransformStmt bndrs using by = sep [ text "then" <+> whenPprDebug (braces (ppr bndrs)) , nest 2 (ppr using) , nest 2 (pprBy by)] pprTransStmt :: Outputable body => Maybe body -> body -> TransForm -> SDoc pprTransStmt by using ThenForm = sep [ text "then", nest 2 (ppr using), nest 2 (pprBy by)] pprTransStmt by using GroupForm = sep [ text "then group", nest 2 (pprBy by), nest 2 (text "using" <+> ppr using)] pprBy :: Outputable body => Maybe body -> SDoc pprBy Nothing = empty pprBy (Just e) = text "by" <+> ppr e pprDo :: (OutputableBndrId p, Outputable body, Anno (StmtLR (GhcPass p) (GhcPass p) body) ~ SrcSpanAnnA ) => HsDoFlavour -> [LStmt (GhcPass p) body] -> SDoc pprDo (DoExpr m) stmts = ppr_module_name_prefix m <> text "do" <+> ppr_do_stmts stmts pprDo GhciStmtCtxt stmts = text "do" <+> ppr_do_stmts stmts pprDo (MDoExpr m) stmts = ppr_module_name_prefix m <> text "mdo" <+> ppr_do_stmts stmts pprDo ListComp stmts = brackets $ pprComp stmts pprDo MonadComp stmts = brackets $ pprComp stmts pprArrowExpr :: (OutputableBndrId p, Outputable body, Anno (StmtLR (GhcPass p) (GhcPass p) body) ~ SrcSpanAnnA ) => [LStmt (GhcPass p) body] -> SDoc pprArrowExpr stmts = text "do" <+> ppr_do_stmts stmts ppr_module_name_prefix :: Maybe ModuleName -> SDoc ppr_module_name_prefix = \case Nothing -> empty Just module_name -> ppr module_name <> char '.' ppr_do_stmts :: (OutputableBndrId idL, OutputableBndrId idR, Anno (StmtLR (GhcPass idL) (GhcPass idR) body) ~ SrcSpanAnnA, Outputable body) => [LStmtLR (GhcPass idL) (GhcPass idR) body] -> SDoc -- Print a bunch of do stmts ppr_do_stmts stmts = pprDeeperList vcat (map ppr stmts) pprComp :: (OutputableBndrId p, Outputable body, Anno (StmtLR (GhcPass p) (GhcPass p) body) ~ SrcSpanAnnA) => [LStmt (GhcPass p) body] -> SDoc pprComp quals -- Prints: body | qual1, ..., qualn | Just (initStmts, L _ (LastStmt _ body _ _)) <- snocView quals = if null initStmts -- If there are no statements in a list comprehension besides the last -- one, we simply treat it like a normal list. This does arise -- occasionally in code that GHC generates, e.g., in implementations of -- 'range' for derived 'Ix' instances for product datatypes with exactly -- one constructor (e.g., see #12583). then ppr body else hang (ppr body <+> vbar) 2 (pprQuals initStmts) | otherwise = pprPanic "pprComp" (pprQuals quals) pprQuals :: (OutputableBndrId p, Outputable body, Anno (StmtLR (GhcPass p) (GhcPass p) body) ~ SrcSpanAnnA) => [LStmt (GhcPass p) body] -> SDoc -- Show list comprehension qualifiers separated by commas pprQuals quals = interpp'SP quals {- ************************************************************************ * * Template Haskell quotation brackets * * ************************************************************************ -} newtype HsSplicedT = HsSplicedT DelayedSplice deriving (Data) type instance XTypedSplice (GhcPass _) = EpAnn [AddEpAnn] type instance XUntypedSplice (GhcPass _) = EpAnn [AddEpAnn] type instance XQuasiQuote (GhcPass _) = NoExtField type instance XSpliced (GhcPass _) = NoExtField type instance XXSplice GhcPs = DataConCantHappen type instance XXSplice GhcRn = DataConCantHappen type instance XXSplice GhcTc = HsSplicedT -- See Note [Running typed splices in the zonker] -- These are the arguments that are passed to `GHC.Tc.Gen.Splice.runTopSplice` data DelayedSplice = DelayedSplice TcLclEnv -- The local environment to run the splice in (LHsExpr GhcRn) -- The original renamed expression TcType -- The result type of running the splice, unzonked (LHsExpr GhcTc) -- The typechecked expression to run and splice in the result -- A Data instance which ignores the argument of 'DelayedSplice'. instance Data DelayedSplice where gunfold _ _ _ = panic "DelayedSplice" toConstr a = mkConstr (dataTypeOf a) "DelayedSplice" [] Data.Prefix dataTypeOf a = mkDataType "HsExpr.DelayedSplice" [toConstr a] -- See Note [Pending Splices] type SplicePointName = Name -- | Pending Renamer Splice data PendingRnSplice = PendingRnSplice UntypedSpliceFlavour SplicePointName (LHsExpr GhcRn) -- | Pending Type-checker Splice data PendingTcSplice = PendingTcSplice SplicePointName (LHsExpr GhcTc) {- Note [Pending Splices] ~~~~~~~~~~~~~~~~~~~~~~ When we rename an untyped bracket, we name and lift out all the nested splices, so that when the typechecker hits the bracket, it can typecheck those nested splices without having to walk over the untyped bracket code. So for example [| f $(g x) |] looks like HsUntypedBracket _ (HsApp (HsVar "f") (HsSpliceE _ (HsUntypedSplice sn (g x))) which the renamer rewrites to HsUntypedBracket [PendingRnSplice UntypedExpSplice sn (g x)] (HsApp (HsVar f) (HsSpliceE _ (HsUntypedSplice sn (g x))) * The 'sn' is the Name of the splice point, the SplicePointName * The PendingRnExpSplice gives the splice that splice-point name maps to; and the typechecker can now conveniently find these sub-expressions * Note that a nested splice, such as the `$(g x)` now appears twice: - In the PendingRnSplice: this is the version that will later be typechecked - In the HsSpliceE in the body of the bracket. This copy is used only for pretty printing. There are four varieties of pending splices generated by the renamer, distinguished by their UntypedSpliceFlavour * Pending expression splices (UntypedExpSplice), e.g., [|$(f x) + 2|] UntypedExpSplice is also used for * quasi-quotes, where the pending expression expands to $(quoter "...blah...") (see GHC.Rename.Splice.makePending, HsQuasiQuote case) * cross-stage lifting, where the pending expression expands to $(lift x) (see GHC.Rename.Splice.checkCrossStageLifting) * Pending pattern splices (UntypedPatSplice), e.g., [| \$(f x) -> x |] * Pending type splices (UntypedTypeSplice), e.g., [| f :: $(g x) |] * Pending declaration (UntypedDeclSplice), e.g., [| let $(f x) in ... |] There is a fifth variety of pending splice, which is generated by the type checker: * Pending *typed* expression splices, (PendingTcSplice), e.g., [||1 + $$(f 2)||] -} instance OutputableBndrId p => Outputable (HsSplicedThing (GhcPass p)) where ppr (HsSplicedExpr e) = ppr_expr e ppr (HsSplicedTy t) = ppr t ppr (HsSplicedPat p) = ppr p instance (OutputableBndrId p) => Outputable (HsSplice (GhcPass p)) where ppr s = pprSplice s pprPendingSplice :: (OutputableBndrId p) => SplicePointName -> LHsExpr (GhcPass p) -> SDoc pprPendingSplice n e = angleBrackets (ppr n <> comma <+> ppr (stripParensLHsExpr e)) pprSpliceDecl :: (OutputableBndrId p) => HsSplice (GhcPass p) -> SpliceExplicitFlag -> SDoc pprSpliceDecl e@HsQuasiQuote{} _ = pprSplice e pprSpliceDecl e ExplicitSplice = text "$" <> ppr_splice_decl e pprSpliceDecl e ImplicitSplice = ppr_splice_decl e ppr_splice_decl :: (OutputableBndrId p) => HsSplice (GhcPass p) -> SDoc ppr_splice_decl (HsUntypedSplice _ _ n e) = ppr_splice empty n e empty ppr_splice_decl e = pprSplice e pprSplice :: forall p. (OutputableBndrId p) => HsSplice (GhcPass p) -> SDoc pprSplice (HsTypedSplice _ DollarSplice n e) = ppr_splice (text "$$") n e empty pprSplice (HsTypedSplice _ BareSplice _ _ ) = panic "Bare typed splice" -- impossible pprSplice (HsUntypedSplice _ DollarSplice n e) = ppr_splice (text "$") n e empty pprSplice (HsUntypedSplice _ BareSplice n e) = ppr_splice empty n e empty pprSplice (HsQuasiQuote _ n q _ s) = ppr_quasi n q s pprSplice (HsSpliced _ _ thing) = ppr thing pprSplice (XSplice x) = case ghcPass @p of #if __GLASGOW_HASKELL__ < 811 GhcPs -> dataConCantHappen x GhcRn -> dataConCantHappen x #endif GhcTc -> case x of HsSplicedT _ -> text "Unevaluated typed splice" ppr_quasi :: OutputableBndr p => p -> p -> FastString -> SDoc ppr_quasi n quoter quote = whenPprDebug (brackets (ppr n)) <> char '[' <> ppr quoter <> vbar <> ppr quote <> text "|]" ppr_splice :: (OutputableBndrId p) => SDoc -> (IdP (GhcPass p)) -> LHsExpr (GhcPass p) -> SDoc -> SDoc ppr_splice herald n e trail = herald <> whenPprDebug (brackets (ppr n)) <> ppr e <> trail type instance XExpBr GhcPs = NoExtField type instance XPatBr GhcPs = NoExtField type instance XDecBrL GhcPs = NoExtField type instance XDecBrG GhcPs = NoExtField type instance XTypBr GhcPs = NoExtField type instance XVarBr GhcPs = NoExtField type instance XXQuote GhcPs = DataConCantHappen type instance XExpBr GhcRn = NoExtField type instance XPatBr GhcRn = NoExtField type instance XDecBrL GhcRn = NoExtField type instance XDecBrG GhcRn = NoExtField type instance XTypBr GhcRn = NoExtField type instance XVarBr GhcRn = NoExtField type instance XXQuote GhcRn = DataConCantHappen -- See Note [The life cycle of a TH quotation] type instance XExpBr GhcTc = DataConCantHappen type instance XPatBr GhcTc = DataConCantHappen type instance XDecBrL GhcTc = DataConCantHappen type instance XDecBrG GhcTc = DataConCantHappen type instance XTypBr GhcTc = DataConCantHappen type instance XVarBr GhcTc = DataConCantHappen type instance XXQuote GhcTc = NoExtField instance OutputableBndrId p => Outputable (HsQuote (GhcPass p)) where ppr = pprHsQuote where pprHsQuote :: forall p. (OutputableBndrId p) => HsQuote (GhcPass p) -> SDoc pprHsQuote (ExpBr _ e) = thBrackets empty (ppr e) pprHsQuote (PatBr _ p) = thBrackets (char 'p') (ppr p) pprHsQuote (DecBrG _ gp) = thBrackets (char 'd') (ppr gp) pprHsQuote (DecBrL _ ds) = thBrackets (char 'd') (vcat (map ppr ds)) pprHsQuote (TypBr _ t) = thBrackets (char 't') (ppr t) pprHsQuote (VarBr _ True n) = char '\'' <> pprPrefixOcc (unLoc n) pprHsQuote (VarBr _ False n) = text "''" <> pprPrefixOcc (unLoc n) pprHsQuote (XQuote b) = case ghcPass @p of #if __GLASGOW_HASKELL__ <= 900 GhcPs -> dataConCantHappen b GhcRn -> dataConCantHappen b #endif GhcTc -> pprPanic "pprHsQuote: `HsQuote GhcTc` shouldn't exist" (ppr b) -- See Note [The life cycle of a TH quotation] thBrackets :: SDoc -> SDoc -> SDoc thBrackets pp_kind pp_body = char '[' <> pp_kind <> vbar <+> pp_body <+> text "|]" thTyBrackets :: SDoc -> SDoc thTyBrackets pp_body = text "[||" <+> pp_body <+> text "||]" instance Outputable PendingRnSplice where ppr (PendingRnSplice _ n e) = pprPendingSplice n e instance Outputable PendingTcSplice where ppr (PendingTcSplice n e) = pprPendingSplice n e ppr_with_pending_tc_splices :: SDoc -> [PendingTcSplice] -> SDoc ppr_with_pending_tc_splices x [] = x ppr_with_pending_tc_splices x ps = x $$ text "pending(tc)" <+> ppr ps {- ************************************************************************ * * \subsection{Enumerations and list comprehensions} * * ************************************************************************ -} instance OutputableBndrId p => Outputable (ArithSeqInfo (GhcPass p)) where ppr (From e1) = hcat [ppr e1, pp_dotdot] ppr (FromThen e1 e2) = hcat [ppr e1, comma, space, ppr e2, pp_dotdot] ppr (FromTo e1 e3) = hcat [ppr e1, pp_dotdot, ppr e3] ppr (FromThenTo e1 e2 e3) = hcat [ppr e1, comma, space, ppr e2, pp_dotdot, ppr e3] pp_dotdot :: SDoc pp_dotdot = text " .. " {- ************************************************************************ * * \subsection{HsMatchCtxt} * * ************************************************************************ -} instance OutputableBndrId p => Outputable (HsMatchContext (GhcPass p)) where ppr m@(FunRhs{}) = text "FunRhs" <+> ppr (mc_fun m) <+> ppr (mc_fixity m) ppr LambdaExpr = text "LambdaExpr" ppr CaseAlt = text "CaseAlt" ppr (LamCaseAlt lc_variant) = text "LamCaseAlt" <+> ppr lc_variant ppr IfAlt = text "IfAlt" ppr (ArrowMatchCtxt c) = text "ArrowMatchCtxt" <+> ppr c ppr PatBindRhs = text "PatBindRhs" ppr PatBindGuards = text "PatBindGuards" ppr RecUpd = text "RecUpd" ppr (StmtCtxt _) = text "StmtCtxt _" ppr ThPatSplice = text "ThPatSplice" ppr ThPatQuote = text "ThPatQuote" ppr PatSyn = text "PatSyn" instance Outputable LamCaseVariant where ppr = text . \case LamCase -> "LamCase" LamCases -> "LamCases" instance Outputable HsArrowMatchContext where ppr ProcExpr = text "ProcExpr" ppr ArrowCaseAlt = text "ArrowCaseAlt" ppr (ArrowLamCaseAlt lc_variant) = parens $ text "ArrowLamCaseAlt" <+> ppr lc_variant ppr KappaExpr = text "KappaExpr" ----------------- instance OutputableBndrId p => Outputable (HsStmtContext (GhcPass p)) where ppr = pprStmtContext -- Used to generate the string for a *runtime* error message matchContextErrString :: OutputableBndrId p => HsMatchContext (GhcPass p) -> SDoc matchContextErrString (FunRhs{mc_fun=L _ fun}) = text "function" <+> ppr fun matchContextErrString CaseAlt = text "case" matchContextErrString (LamCaseAlt lc_variant) = lamCaseKeyword lc_variant matchContextErrString IfAlt = text "multi-way if" matchContextErrString PatBindRhs = text "pattern binding" matchContextErrString PatBindGuards = text "pattern binding guards" matchContextErrString RecUpd = text "record update" matchContextErrString LambdaExpr = text "lambda" matchContextErrString (ArrowMatchCtxt c) = matchArrowContextErrString c matchContextErrString ThPatSplice = panic "matchContextErrString" -- Not used at runtime matchContextErrString ThPatQuote = panic "matchContextErrString" -- Not used at runtime matchContextErrString PatSyn = panic "matchContextErrString" -- Not used at runtime matchContextErrString (StmtCtxt (ParStmtCtxt c)) = matchContextErrString (StmtCtxt c) matchContextErrString (StmtCtxt (TransStmtCtxt c)) = matchContextErrString (StmtCtxt c) matchContextErrString (StmtCtxt (PatGuard _)) = text "pattern guard" matchContextErrString (StmtCtxt (ArrowExpr)) = text "'do' block" matchContextErrString (StmtCtxt (HsDoStmt flavour)) = matchDoContextErrString flavour matchArrowContextErrString :: HsArrowMatchContext -> SDoc matchArrowContextErrString ProcExpr = text "proc" matchArrowContextErrString ArrowCaseAlt = text "case" matchArrowContextErrString (ArrowLamCaseAlt lc_variant) = lamCaseKeyword lc_variant matchArrowContextErrString KappaExpr = text "kappa" matchDoContextErrString :: HsDoFlavour -> SDoc matchDoContextErrString GhciStmtCtxt = text "interactive GHCi command" matchDoContextErrString (DoExpr m) = prependQualified m (text "'do' block") matchDoContextErrString (MDoExpr m) = prependQualified m (text "'mdo' block") matchDoContextErrString ListComp = text "list comprehension" matchDoContextErrString MonadComp = text "monad comprehension" pprMatchInCtxt :: (OutputableBndrId idR, Outputable body) => Match (GhcPass idR) body -> SDoc pprMatchInCtxt match = hang (text "In" <+> pprMatchContext (m_ctxt match) <> colon) 4 (pprMatch match) pprStmtInCtxt :: (OutputableBndrId idL, OutputableBndrId idR, OutputableBndrId ctx, Outputable body, Anno (StmtLR (GhcPass idL) (GhcPass idR) body) ~ SrcSpanAnnA) => HsStmtContext (GhcPass ctx) -> StmtLR (GhcPass idL) (GhcPass idR) body -> SDoc pprStmtInCtxt ctxt (LastStmt _ e _ _) | isComprehensionContext ctxt -- For [ e | .. ], do not mutter about "stmts" = hang (text "In the expression:") 2 (ppr e) pprStmtInCtxt ctxt stmt = hang (text "In a stmt of" <+> pprAStmtContext ctxt <> colon) 2 (ppr_stmt stmt) where -- For Group and Transform Stmts, don't print the nested stmts! ppr_stmt (TransStmt { trS_by = by, trS_using = using , trS_form = form }) = pprTransStmt by using form ppr_stmt stmt = pprStmt stmt {- ************************************************************************ * * \subsection{Anno instances} * * ************************************************************************ -} type instance Anno (HsExpr (GhcPass p)) = SrcSpanAnnA type instance Anno [LocatedA ((StmtLR (GhcPass pl) (GhcPass pr) (LocatedA (HsExpr (GhcPass pr)))))] = SrcSpanAnnL type instance Anno [LocatedA ((StmtLR (GhcPass pl) (GhcPass pr) (LocatedA (HsCmd (GhcPass pr)))))] = SrcSpanAnnL type instance Anno (HsCmd (GhcPass p)) = SrcSpanAnnA type instance Anno [LocatedA (StmtLR (GhcPass pl) (GhcPass pr) (LocatedA (HsCmd (GhcPass pr))))] = SrcSpanAnnL type instance Anno (HsCmdTop (GhcPass p)) = SrcAnn NoEpAnns type instance Anno [LocatedA (Match (GhcPass p) (LocatedA (HsExpr (GhcPass p))))] = SrcSpanAnnL type instance Anno [LocatedA (Match (GhcPass p) (LocatedA (HsCmd (GhcPass p))))] = SrcSpanAnnL type instance Anno (Match (GhcPass p) (LocatedA (HsExpr (GhcPass p)))) = SrcSpanAnnA type instance Anno (Match (GhcPass p) (LocatedA (HsCmd (GhcPass p)))) = SrcSpanAnnA type instance Anno (GRHS (GhcPass p) (LocatedA (HsExpr (GhcPass p)))) = SrcAnn NoEpAnns type instance Anno (GRHS (GhcPass p) (LocatedA (HsCmd (GhcPass p)))) = SrcAnn NoEpAnns type instance Anno (StmtLR (GhcPass pl) (GhcPass pr) (LocatedA (HsExpr (GhcPass pr)))) = SrcSpanAnnA type instance Anno (StmtLR (GhcPass pl) (GhcPass pr) (LocatedA (HsCmd (GhcPass pr)))) = SrcSpanAnnA type instance Anno (HsSplice (GhcPass p)) = SrcSpanAnnA type instance Anno [LocatedA (StmtLR (GhcPass pl) (GhcPass pr) (LocatedA (HsExpr (GhcPass pr))))] = SrcSpanAnnL type instance Anno [LocatedA (StmtLR (GhcPass pl) (GhcPass pr) (LocatedA (HsCmd (GhcPass pr))))] = SrcSpanAnnL type instance Anno (FieldLabelStrings (GhcPass p)) = SrcAnn NoEpAnns type instance Anno (FieldLabelString) = SrcAnn NoEpAnns type instance Anno (DotFieldOcc (GhcPass p)) = SrcAnn NoEpAnns instance (Anno a ~ SrcSpanAnn' (EpAnn an)) => WrapXRec (GhcPass p) a where wrapXRec = noLocA