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[GHC] #16403: Add isBinDigit to Data.Char
by GHC 07 Mar '19

07 Mar '19

#16403: Add isBinDigit to Data.Char -------------------------------------+------------------------------------- Reporter: hesiod | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: | Version: 8.6.4 libraries/base | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The {{{Data.Char}}} module contains helper functions that determine whether a Char is a decimal, octal or hexadecimal digit ({{{isDigit}}}, {{{isOctDigit}}}, {{{isHexDigit}}}). A similar helper function for binary digits is not included for no apparent reason (maybe because the number parsers in the {{{Numeric}}} module also don't support binary digits?). The implementation for such a {{{isBinDigit}}} should be trivial, aside from performance considerations: {{{isDigit}}} and friends perform the test using only subtraction and an unsigned comparison, I'm not sure whether {{{isBinDigit}}} offers any different performant implementations. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16403> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11715: There's something fishy going on with Constraint
by GHC 07 Mar '19

07 Mar '19

#11715: There's something fishy going on with Constraint -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc1 (Type checker) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I first noticed something was a bit odd with `Constraint` when chasing #11334. Consider this testcase, {{{#!hs import Data.Typeable main = do print $ typeRep (Proxy :: Proxy Eq) print $ typeOf (Proxy :: Proxy Eq) }}} With `ghc-8.0` this will produce, {{{ Eq Proxy (* -> *) Eq }}} Notice the second line; GHC seems to be claiming that `Eq :: * -> *`, which is clearly nonsense. I believe this issue may be the cause of some of the testsuite failures that I'm seeing on #11011. Unfortunately I haven't the foggiest where this issue might originate. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11715> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15918: GHC panic from TypeApplications(?)
by GHC 07 Mar '19

07 Mar '19

#15918: GHC panic from TypeApplications(?) -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.3 Component: Compiler | Version: 8.6.2 Keywords: | Operating System: Unknown/Multiple TypeApplications | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Minimized from https://gist.github.com/Icelandjack/683bd4b79027695ffc31632645c9d58b, I don't expect `Build []` to kind check but ti shouldn't crash. {{{#!hs {-# Language PolyKinds #-} {-# Language TypeFamilies #-} {-# Language ConstraintKinds #-} {-# Language FlexibleContexts #-} {-# Language QuantifiedConstraints #-} {-# Language UndecidableInstances #-} import Data.Kind class Rev f where rev :: f a instance (forall xx. cls xx => Rev xx) => Rev (Build cls) where rev = undefined data Build :: ((k -> Type) -> Constraint) -> (k -> Type) uu = rev :: Build [] a }}} gives a panic {{{ $ ghc-stage2 --interactive -ignore-dot-ghci ~/hs/711_bug.hs GHCi, version 8.7.20181029: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( ~/hs/711_bug.hs, interpreted ) ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.7.20181029 for x86_64-unknown-linux): ASSERT failed! irred_a1zW :: [(xx_a1zV[sk:3] |> Sym {co_a1zu})] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1160:37 in ghc:Outputable pprPanic, called at compiler/utils/Outputable.hs:1219:5 in ghc:Outputable assertPprPanic, called at compiler/typecheck/TcType.hs:1826:53 in ghc:TcType Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug > }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15918> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15799: GHC panic (and warnings)
by GHC 07 Mar '19

07 Mar '19

#15799: GHC panic (and warnings) -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- On the [https://phabricator.haskell.org/D5229 visible kind application] differential, {{{#!hs {-# Language CPP #-} {-# Language DataKinds #-} {-# Language RankNTypes #-} {-# Language PatternSynonyms #-} {-# Language TypeOperators #-} {-# Language PolyKinds #-} {-# Language GADTs #-} {-# Language TypeFamilies #-} {-# Language TypeApplications #-} {-# Language FlexibleContexts #-} {-# Language FlexibleInstances #-} {-# Language InstanceSigs #-} import qualified GHC.TypeLits as TypeLits import GHC.TypeLits (Nat, KnownNat) import Data.Kind data Op obj = Op obj type family UnOp (op_a :: Op obj) :: obj where UnOp ('Op obj) = obj class Ríki (obj :: Type) where type (-->) :: Op obj -> obj -> Type type (<--) :: obj -> Op obj -> Type unop :: forall (a :: obj) (b :: obj). (a <-- 'Op b) -> ('Op b --> a) data (<=) :: Op Nat -> Nat -> Type where LessThan :: (KnownNat (UnOp op_a), KnownNat b, UnOp op_a TypeLits.<= b) => (op_a <= b) newtype (>=) :: Nat -> Op Nat -> Type where Y :: (a <= b) -> (b >= a) instance Ríki Nat where type (-->) = (<=) type (<--) = (>=) unop :: (a >= b) -> (b <= a) unop GreaterThan = LessThan pattern GreaterThan :: () => (KnownNat (UnOp b), KnownNat a, UnOp b <= a) => a >= b pattern GreaterThan = Y LessThan }}} {{{ $ ghci -ignore-dot-ghci 573_bug.hs GHCi, version 8.7.20181017: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( 573_bug.hs, interpreted ) WARNING: file compiler/types/TyCoRep.hs, line 2567 in_scope InScope {b_a1Em a_a1En} tenv [a1Em :-> b_a1Em[sk:0], a1En :-> a_a1En[sk:0]] cenv [] tys [KnownNat (UnOp b_a1Em[sk:1]), KnownNat a_a1En[sk:1], (UnOp b_a1Em[sk:1] |> {co_a1HN}) <= a_a1En[sk:1]] cos [] needInScope [a1HN :-> co_a1HN] WARNING: file compiler/types/TyCoRep.hs, line 2567 in_scope InScope {b_a1Jo a_a1Jp} tenv [a1Em :-> b_a1Jo[tau:3], a1En :-> a_a1Jp[tau:3]] cenv [] tys [KnownNat (UnOp b_a1Em), KnownNat a_a1En, (UnOp b_a1Em |> {co_a1HN}) <= a_a1En] cos [] needInScope [a1HN :-> co_a1HN] ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.7.20181017 for x86_64-unknown-linux): tcEvVarPred irred_a1Js (UnOp b_a1Jo[tau:3] |> {co_a1HN}) <= a_a1Jp[tau:3] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1160:37 in ghc:Outputable pprPanic, called at compiler/typecheck/TcType.hs:1998:20 in ghc:TcType Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug > }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15799> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16402: GHC doesnt' notice that (narrowWordFOO (x .&. FOO)) is just `x`.
by GHC 06 Mar '19

06 Mar '19

#16402: GHC doesnt' notice that (narrowWordFOO (x .&. FOO)) is just `x`. -------------------------------------+------------------------------------- Reporter: Fuuzetsu | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# OPTIONS_GHC -ddump-simpl -ddump-to-file -dhex-word-literals -O2 #-} {-# LANGUAGE TypeApplications #-} module NarrowWord where import Data.Word import Data.Bits smallWord_foo :: Word64 -> Word64 smallWord_foo x = fromIntegral @Word16 $ fromIntegral (x .&. 0xFFFF) smallWord_bar :: Word64 -> Word64 smallWord_bar x = fromIntegral @Word16 $ fromIntegral x test :: Bool test = let w = 72430412501 in smallWord_foo w == smallWord_bar w }}} {{{#!hs -- RHS size: {terms: 7, types: 3, coercions: 0, joins: 0/0} smallWord_bar :: Word64 -> Word64 [GblId, Arity=1, Caf=NoCafRefs, Str=<S(S),1*U(U)>m, Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=False) Tmpl= \ (x_a1so [Occ=Once!] :: Word64) -> case x_a1so of { GHC.Word.W64# x#_a2Mw [Occ=Once] -> GHC.Word.W64# (GHC.Prim.narrow16Word# x#_a2Mw) }}] smallWord_bar = \ (x_a1so :: Word64) -> case x_a1so of { GHC.Word.W64# x#_a2Mw -> GHC.Word.W64# (GHC.Prim.narrow16Word# x#_a2Mw) } -- RHS size: {terms: 9, types: 3, coercions: 0, joins: 0/0} smallWord_foo :: Word64 -> Word64 [GblId, Arity=1, Caf=NoCafRefs, Str=<S(S),1*U(U)>m, Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=False) Tmpl= \ (x_a1hU [Occ=Once!] :: Word64) -> case x_a1hU of { GHC.Word.W64# x#_a30a [Occ=Once] -> GHC.Word.W64# (GHC.Prim.narrow16Word# (GHC.Prim.and# x#_a30a 0xffff##)) }}] smallWord_foo = \ (x_a1hU :: Word64) -> case x_a1hU of { GHC.Word.W64# x#_a30a -> GHC.Word.W64# (GHC.Prim.narrow16Word# (GHC.Prim.and# x#_a30a 0xffff##)) } -- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0} test :: Bool [GblId, Caf=NoCafRefs, Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=0,unsat_ok=True,boring_ok=True) Tmpl= GHC.Types.True}] test = GHC.Types.True }}} For Word8, Word16, Word32, Word64 and Int8, Int16, Int32, Int64, I would expect GHC to never produce the {{{and}}}. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16402> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16401: Bad error message if we use TypeApplications with an identifier that doesn't exist
by GHC 06 Mar '19

06 Mar '19

#16401: Bad error message if we use TypeApplications with an identifier that doesn't exist -------------------------------------+------------------------------------- Reporter: Fuuzetsu | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE TypeApplications #-} {-# LANGUAGE DataKinds #-} module BadError where foo :: Int foo = doesNotExist @123 {- [1 of 1] Compiling BadError ( BadError.hs, BadError.o ) BadError.hs:6:7: error: • Cannot apply expression of type ‘t1’ to a visible type argument ‘123’ • In the expression: doesNotExist @123 In an equation for ‘foo’: foo = doesNotExist @123 | 6 | foo = doesNotExist @123 -} }}} What I would expect is for it to say that {{{doesNotExist}}} is not bound as one might reasonably expect. This is very, very confusing and easy to hit in real life. If you are exposing a function {{{f}}}, using it somewhere with {{{f @123}}} but then later decide to remove or rename {{{f}}}, the error message doesn't suggest at all that {{{f}}} has disappeared and leaves the user scratching their head. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16401> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16385: Lousy error message for `instance forall c. c`
by GHC 06 Mar '19

06 Mar '19

#16385: Lousy error message for `instance forall c. c` -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Poor/confusing Unknown/Multiple | error message Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This erroneous program is rejected with a rather strange error message: {{{#!hs {-# LANGUAGE ScopedTypeVariables #-} module Bug where instance forall c. c }}} {{{ $ /opt/ghc/8.6.3/bin/ghc Bug.hs [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) Bug.hs:4:20: error: Not in scope: type variable ‘c’ | 4 | instance forall c. c | ^ }}} This error message is hogwash, since `c` is absolutely in scope. The reason GHC believes that `c` is out of scope is because before GHC renamed the type signature in the instance, it performs a pass over all top-level binders in `RnNames.getLocalNonValBinders` to obtain their `Name`s. In particular, [https://gitlab.haskell.org/ghc/ghc/blob/473632d7671619ee08a2a0025aa22bd4f79… this] is the culprit: {{{#!hs new_assoc overload_ok (L _ (ClsInstD _ (ClsInstDecl { cid_poly_ty = inst_ty , cid_datafam_insts = adts }))) | Just (L loc cls_rdr) <- getLHsInstDeclClass_maybe inst_ty = do { cls_nm <- setSrcSpan loc $ lookupGlobalOccRn cls_rdr ; (avails, fldss) <- mapAndUnzipM (new_loc_di overload_ok (Just cls_nm)) adts ; return (avails, concat fldss) } | otherwise = return ([], []) -- Do not crash on ill-formed instances -- Eg instance !Show Int Trac #3811c }}} Notice the use of `lookupGlobalOccRn` there. Since this code just tunnels into the instance type signature (using `getLHsInstDeclClass_maybe`) without binding any type variables, this calls `lookupGlobalOcc` on an unbound type variable `c`. Eek. I believe the fix would be to use `lookupGlobalOccRn_maybe` instead and simply default to `return ([], [])` in the event that `lookupGlobalOccRn_maybe` returns Nothing. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16385> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16187: Hadrian: Build fails when using absolute path for build root
by GHC 06 Mar '19

06 Mar '19

#16187: Hadrian: Build fails when using absolute path for build root -------------------------------------+------------------------------------- Reporter: davide | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 8.6.3 (Hadrian) | Keywords: hadrian build | Operating System: Linux root relative absolute path | Architecture: | Type of failure: Building GHC Unknown/Multiple | failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This fails: {{{ $ git clean -xdf $ ./boot && ./configure && ./hadrian/build.sh -o/tmp/build ... Error when running Shake build system: at src/Main.hs:58:30-42: * Depends on: test at src/Hadrian/Builder.hs:70:5-23: * Depends on: /tmp/build01/stage2/lib/platformConstants at src/Hadrian/Utilities.hs:292:5-18: * Depends on: /tmp/build01/generated/platformConstants at src/Hadrian/Builder.hs:70:5-23: * Depends on: /tmp/build01/stage0/bin/deriveConstants at src/Development/Shake/Internal/Rules/Oracle.hs:157:43-68: * Depends on: OracleQ (ContextDataKey (Context {stage = Stage0, package = Package {pkgType = Program, pkgName = "deriveConstants", pkgPath = "utils/deriveConstants"}, way = v})) at src/Hadrian/Haskell/Cabal/Parse.hs:214:5-36: * Depends on: /tmp/build01/stage0/utils/deriveConstants/setup-config * Raised the exception: Error, rule finished running but did not produce file: /tmp/build01/stage0/utils/deriveConstants/setup-config CallStack (from HasCallStack): error, called at src/Development/Shake/Internal/Rules/File.hs:180:58 in shake-0.17.4-5aa097213b9663d13b00fb582ca77bb18e6d60c3b0376f0fc60fdbf22a73c6f4:Development.Shake.Internal.Rules.File }}} but changing `/tmp/build` to the relative path succeeds (something like `-o../../../../tmp/build`). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16187> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12509: ghci -XSafe fails in an inscrutable way
by GHC 06 Mar '19

06 Mar '19

#12509: ghci -XSafe fails in an inscrutable way -------------------------------------+------------------------------------- Reporter: int-e | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Trying to run `ghci -XSafe` produces the following output: {{{ GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help <interactive>:1:6: error: Not in scope: ‘System.IO.hSetBuffering’ No module named ‘System.IO’ is imported. <interactive>:1:30: error: Not in scope: ‘System.IO.stdin’ No module named ‘System.IO’ is imported. <interactive>:1:46: error: Not in scope: data constructor ‘System.IO.NoBuffering’ No module named ‘System.IO’ is imported. <interactive>:1:70: error: Not in scope: ‘System.IO.hSetBuffering’ No module named ‘System.IO’ is imported. <interactive>:1:94: error: Not in scope: ‘System.IO.stdout’ No module named ‘System.IO’ is imported. <interactive>:1:111: error: Not in scope: data constructor ‘System.IO.NoBuffering’ No module named ‘System.IO’ is imported. <interactive>:1:135: error: Not in scope: ‘System.IO.hSetBuffering’ No module named ‘System.IO’ is imported. <interactive>:1:159: error: Not in scope: ‘System.IO.stderr’ No module named ‘System.IO’ is imported. <interactive>:1:176: error: Not in scope: data constructor ‘System.IO.NoBuffering’ No module named ‘System.IO’ is imported. }}} I'm not sure whether this should work, but in any case the error message is horrible. I tried adding `-trust base` to no avail. For comparison, ghc-7.10.3 starts with no trouble: {{{ > ghci -XSafe GHCi, version 7.10.2: http://www.haskell.org/ghc/ :? for help Prelude> }}} (Motivation: I'm using ghci in Safe mode to track down import problems with SafeHaskell. As a workaround, I can use `:set -XSafe` after ghci's startup is done.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12509> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16399: Error when running --share
by GHC 06 Mar '19

06 Mar '19

#16399: Error when running --share -------------------------------------+------------------------------------- Reporter: phadej | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: (Hadrian) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- On a fresh checkout, db039a4a10fc8fa9e03e6781d1c0dc33151beda6 {{{ # succeeds ./hadrian/build.sh --progress-colour=Never --share=_share -j3 ... # fails ./hadrian/build.sh --progress-colour=Never --share=_share -j3 --build- root=_build-experiment ... # this succeeds ok ./hadrian/build.sh --progress-colour=Never --share=_share -j3 ... Build completed in 6.97s # Trying without share: still fails with the same error ./hadrian/build.sh --progress-colour=Never -j3 --build-root=_build- experiment ... | Run Ghc CompileHs Stage1: libraries/ghc-prim/GHC/Classes.hs => _build- baseline/stage1/libraries/ghc-prim/build/GHC/Classes.p_o Error when running Shake build system: at action, called at src/Rules.hs:35:19 in main:Rules at need, called at src/Rules.hs:52:5 in main:Rules * Depends on: _build-baseline/stage1/bin/ghc-pkg at need, called at src/Utilities.hs:71:18 in main:Utilities * Depends on: _build-baseline/stage1/libraries/integer-gmp/build /libHSinteger-gmp-1.0.2.0-ghc8.9.20190306.so at need, called at src/Rules/Gmp.hs:14:5 in main:Rules.Gmp * Depends on: _build-baseline/stage1/gmp/include/ghc-gmp.h at need, called at src/Development/Shake/Internal/Derived.hs:118:15 in shake-0.17.6-ef5d6f7a92b6a347b5077f2591e0d47990d974d264275e5e4048829d4b393706:Development.Shake.Internal.Derived * Depends on: _build-baseline/stage1/libraries/integer-gmp/build/config.mk at error, called at src/Development/Shake/Internal/Rules/File.hs:180:58 in shake-0.17.6-ef5d6f7a92b6a347b5077f2591e0d47990d974d264275e5e4048829d4b393706:Development.Shake.Internal.Rules.File * Raised the exception: Error, file does not exist and no rule available: _build-baseline/stage1/libraries/integer-gmp/build/config.mk }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16399> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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