Vladislav Zavialov pushed to branch wip/int-index/no-multiline at Glasgow Haskell Compiler / GHC Commits: 2aeefaee by Vladislav Zavialov at 2026-01-31T15:56:45+03:00 Refactor: merge HsMultilineString into HsString (#26860) Before this patch, HsLit defined two separate constructors to represent single-line and multi-line strings: data HsLit x ... | HsString (XHsString x) FastString | HsMultilineString (XHsMultilineString x) FastString I found this to be an unnecessary complication and an obstacle to unifying HsLit with HsTyLit. Now we use HsString for both kinds of literals. One user-facing change here is `ppr (HsString st s)` behaving differently for single-line strings containing newlines: x = "first line \ \asdf\n\ \second line" Previously, the literal was fed to `ftext` with its newlines, producing an ill-formed SDoc. This issue is now addressed by using `split` for both single-line and multi-line strings: vcat $ map text $ split '\n' (unpackFS src) See the parser/should_fail/T26860ppr test. In addition (and unrelatedly to the main payload of this patch), drop the unused pmPprHsLit helper. - - - - - 14 changed files: - compiler/GHC/Hs/Lit.hs - compiler/GHC/Hs/Syn/Type.hs - compiler/GHC/HsToCore/Match/Literal.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/String.hs - compiler/GHC/Rename/Expr.hs - compiler/GHC/Tc/Gen/HsType.hs - compiler/Language/Haskell/Syntax/Extension.hs - compiler/Language/Haskell/Syntax/Lit.hs - + testsuite/tests/parser/should_fail/T26860ppr.hs - + testsuite/tests/parser/should_fail/T26860ppr.stderr - testsuite/tests/parser/should_fail/all.T - utils/check-exact/ExactPrint.hs Changes: ===================================== compiler/GHC/Hs/Lit.hs ===================================== @@ -45,7 +45,6 @@ import Language.Haskell.Syntax.Lit type instance XHsChar (GhcPass _) = SourceText type instance XHsCharPrim (GhcPass _) = SourceText type instance XHsString (GhcPass _) = SourceText -type instance XHsMultilineString (GhcPass _) = SourceText type instance XHsStringPrim (GhcPass _) = SourceText type instance XHsInt (GhcPass _) = NoExtField type instance XHsIntPrim (GhcPass _) = SourceText @@ -147,7 +146,6 @@ hsLitNeedsParens p = go go (HsChar {}) = False go (HsCharPrim {}) = False go (HsString {}) = False - go (HsMultilineString {}) = False go (HsStringPrim {}) = False go (HsInt _ x) = p > topPrec && il_neg x go (HsFloatPrim {}) = False @@ -177,7 +175,6 @@ convertLit :: XXLit (GhcPass p)~DataConCantHappen => HsLit (GhcPass p) -> HsLit convertLit (HsChar a x) = HsChar a x convertLit (HsCharPrim a x) = HsCharPrim a x convertLit (HsString a x) = HsString a x -convertLit (HsMultilineString a x) = HsMultilineString a x convertLit (HsStringPrim a x) = HsStringPrim a x convertLit (HsInt a x) = HsInt a x convertLit (HsIntPrim a x) = HsIntPrim a x @@ -212,8 +209,7 @@ Equivalently it's True if instance IsPass p => Outputable (HsLit (GhcPass p)) where ppr (HsChar st c) = pprWithSourceText st (pprHsChar c) ppr (HsCharPrim st c) = pprWithSourceText st (pprPrimChar c) - ppr (HsString st s) = pprWithSourceText st (pprHsString s) - ppr (HsMultilineString st s) = + ppr (HsString st s) = case st of NoSourceText -> pprHsString s SourceText src -> vcat $ map text $ split '\n' (unpackFS src) @@ -248,36 +244,6 @@ instance Outputable OverLitVal where ppr (HsFractional f) = ppr f ppr (HsIsString st s) = pprWithSourceText st (pprHsString s) --- | pmPprHsLit pretty prints literals and is used when pretty printing pattern --- match warnings. All are printed the same (i.e., without hashes if they are --- primitive and not wrapped in constructors if they are boxed). This happens --- mainly for too reasons: --- * We do not want to expose their internal representation --- * The warnings become too messy -pmPprHsLit :: forall p. IsPass p => HsLit (GhcPass p) -> SDoc -pmPprHsLit (HsChar _ c) = pprHsChar c -pmPprHsLit (HsCharPrim _ c) = pprHsChar c -pmPprHsLit (HsString st s) = pprWithSourceText st (pprHsString s) -pmPprHsLit (HsMultilineString st s) = pprWithSourceText st (pprHsString s) -pmPprHsLit (HsStringPrim _ s) = pprHsBytes s -pmPprHsLit (HsInt _ i) = integer (il_value i) -pmPprHsLit (HsIntPrim _ i) = integer i -pmPprHsLit (HsWordPrim _ w) = integer w -pmPprHsLit (HsInt8Prim _ i) = integer i -pmPprHsLit (HsInt16Prim _ i) = integer i -pmPprHsLit (HsInt32Prim _ i) = integer i -pmPprHsLit (HsInt64Prim _ i) = integer i -pmPprHsLit (HsWord8Prim _ w) = integer w -pmPprHsLit (HsWord16Prim _ w) = integer w -pmPprHsLit (HsWord32Prim _ w) = integer w -pmPprHsLit (HsWord64Prim _ w) = integer w -pmPprHsLit (HsFloatPrim _ f) = ppr f -pmPprHsLit (HsDoublePrim _ d) = ppr d -pmPprHsLit (XLit x) = case ghcPass @p of - GhcTc -> case x of - (HsInteger _ i _) -> integer i - (HsRat f _) -> ppr f - negateOverLitVal :: OverLitVal -> OverLitVal negateOverLitVal (HsIntegral i) = HsIntegral (negateIntegralLit i) negateOverLitVal (HsFractional f) = HsFractional (negateFractionalLit f) ===================================== compiler/GHC/Hs/Syn/Type.hs ===================================== @@ -75,7 +75,6 @@ hsLitType :: forall p. IsPass p => HsLit (GhcPass p) -> Type hsLitType (HsChar _ _) = charTy hsLitType (HsCharPrim _ _) = charPrimTy hsLitType (HsString _ _) = stringTy -hsLitType (HsMultilineString _ _) = stringTy hsLitType (HsStringPrim _ _) = addrPrimTy hsLitType (HsInt _ _) = intTy hsLitType (HsIntPrim _ _) = intPrimTy ===================================== compiler/GHC/HsToCore/Match/Literal.hs ===================================== @@ -117,7 +117,6 @@ dsLit l = do HsDoublePrim _ fl -> return (Lit (LitDouble (rationalFromFractionalLit fl))) HsChar _ c -> return (mkCharExpr c) HsString _ str -> mkStringExprFS str - HsMultilineString _ str -> mkStringExprFS str HsInt _ i -> return (mkIntExpr platform (il_value i)) XLit x -> case ghcPass @p of GhcTc -> case x of @@ -463,7 +462,6 @@ getSimpleIntegralLit (XLit (HsInteger _ i ty)) = Just (i, ty) getSimpleIntegralLit HsChar{} = Nothing getSimpleIntegralLit HsCharPrim{} = Nothing getSimpleIntegralLit HsString{} = Nothing -getSimpleIntegralLit HsMultilineString{} = Nothing getSimpleIntegralLit HsStringPrim{} = Nothing getSimpleIntegralLit (XLit (HsRat{})) = Nothing getSimpleIntegralLit HsFloatPrim{} = Nothing ===================================== compiler/GHC/HsToCore/Quote.hs ===================================== @@ -3077,7 +3077,6 @@ repLiteral lit HsChar _ _ -> Just charLName HsCharPrim _ _ -> Just charPrimLName HsString _ _ -> Just stringLName - HsMultilineString _ _ -> Just stringLName _ -> Nothing mk_integer :: Integer -> MetaM (HsLit GhcTc) ===================================== compiler/GHC/Parser.y ===================================== @@ -4130,7 +4130,7 @@ literal :: { Located (HsLit GhcPs) } : CHAR { sL1 $1 $ HsChar (getCHARs $1) $ getCHAR $1 } | STRING { sL1 $1 $ HsString (getSTRINGs $1) $ getSTRING $1 } - | STRING_MULTI { sL1 $1 $ HsMultilineString (getSTRINGMULTIs $1) + | STRING_MULTI { sL1 $1 $ HsString (getSTRINGMULTIs $1) $ getSTRINGMULTI $1 } | PRIMINTEGER { sL1 $1 $ HsIntPrim (getPRIMINTEGERs $1) $ getPRIMINTEGER $1 } ===================================== compiler/GHC/Parser/String.hs ===================================== @@ -392,9 +392,9 @@ proposal: https://github.com/ghc-proposals/ghc-proposals/pull/569 Multiline string literals are syntax sugar for normal string literals, with an extra post processing step. This all happens in the Lexer; that -is, HsMultilineString will contain the post-processed string. This matches -the same behavior as HsString, which contains the normalized string -(see Note [Literal source text]). +is, the multi-line HsString will contain the post-processed string. +This matches the behavior of the single-line HsString, which contains +the normalized string too (see Note [Literal source text]). The canonical steps for post processing a multiline string are: 1. Collapse string gaps ===================================== compiler/GHC/Rename/Expr.hs ===================================== @@ -352,18 +352,13 @@ rnExpr (HsOverLabel src v) hs_ty_arg = mkEmptyWildCardBndrs $ wrapGenSpan $ HsTyLit noExtField (HsStrTy NoSourceText v) -rnExpr (HsLit x lit) | Just (src, s) <- stringLike lit +rnExpr (HsLit x lit) | HsString src s <- lit = do { opt_OverloadedStrings <- xoptM LangExt.OverloadedStrings ; if opt_OverloadedStrings then rnExpr (HsOverLit x (mkHsIsString src s)) else do { ; rnLit lit ; return (HsLit x (convertLit lit), emptyFVs) } } - where - stringLike = \case - HsString src s -> Just (src, s) - HsMultilineString src s -> Just (src, s) - _ -> Nothing rnExpr (HsLit x lit) = do { rnLit lit ===================================== compiler/GHC/Tc/Gen/HsType.hs ===================================== @@ -4786,7 +4786,6 @@ promotionErr name err tyLitFromLit :: HsLit GhcRn -> Maybe (HsTyLit GhcRn) tyLitFromLit (HsString x str) = Just (HsStrTy x str) -tyLitFromLit (HsMultilineString x str) = Just (HsStrTy x str) tyLitFromLit (HsChar x char) = Just (HsCharTy x char) tyLitFromLit _ = Nothing ===================================== compiler/Language/Haskell/Syntax/Extension.hs ===================================== @@ -604,7 +604,6 @@ type family XXParStmtBlock x x' type family XHsChar x type family XHsCharPrim x type family XHsString x -type family XHsMultilineString x type family XHsStringPrim x type family XHsInt x type family XHsIntPrim x ===================================== compiler/Language/Haskell/Syntax/Lit.hs ===================================== @@ -47,8 +47,6 @@ data HsLit x -- ^ Unboxed character | HsString (XHsString x) {- SourceText -} FastString -- ^ String - | HsMultilineString (XHsMultilineString x) {- SourceText -} FastString - -- ^ String | HsStringPrim (XHsStringPrim x) {- SourceText -} !ByteString -- ^ Packed bytes | HsInt (XHsInt x) IntegralLit ===================================== testsuite/tests/parser/should_fail/T26860ppr.hs ===================================== @@ -0,0 +1,11 @@ +{-# LANGUAGE NoOverloadedStrings #-} + +module T26860ppr where + +-- Test that the error message containing the string literal is well-formatted. +-- See also: parser/should_fail/MultilineStringsError +x :: Int +x = "first line \ + \asdf\n\ + \second line" + ===================================== testsuite/tests/parser/should_fail/T26860ppr.stderr ===================================== @@ -0,0 +1,13 @@ +T26860ppr.hs:8:5: error: [GHC-83865] + • Couldn't match type ‘[Char]’ with ‘Int’ + Expected: Int + Actual: String + • In the expression: + "first line \ + \asdf\n\ + \second line" + In an equation for ‘x’: + x = "first line \ + \asdf\n\ + \second line" + ===================================== testsuite/tests/parser/should_fail/all.T ===================================== @@ -244,3 +244,4 @@ test('T25530', normal, compile_fail, ['']) test('T26418', normal, compile_fail, ['']) test('T12488c', normal, compile_fail, ['']) test('T12488d', normal, compile_fail, ['']) +test('T26860ppr', normal, compile_fail, ['']) ===================================== utils/check-exact/ExactPrint.hs ===================================== @@ -4794,7 +4794,6 @@ hsLit2String lit = HsChar src v -> toSourceTextWithSuffix src v "" HsCharPrim src p -> toSourceTextWithSuffix src p "" HsString src v -> toSourceTextWithSuffix src v "" - HsMultilineString src v -> toSourceTextWithSuffix src v "" HsStringPrim src v -> toSourceTextWithSuffix src v "" HsInt _ (IL src _ v) -> toSourceTextWithSuffix src v "" HsIntPrim src v -> toSourceTextWithSuffix src v "" View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2aeefaee539e7cba900d1722d559c289... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2aeefaee539e7cba900d1722d559c289... You're receiving this email because of your account on gitlab.haskell.org.