January 2019 - ghc-tickets

[GHC] #14069: RTS linker maps code as writable
by GHC 02 Mar '19

02 Mar '19

#14069: RTS linker maps code as writable -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Runtime | Version: 8.0.1 System (Linker) | 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: -------------------------------------+------------------------------------- GHC's RTS linker maps executable code in writable pages, representing a significant potential exploit point for arbitrary code execution. OpenBSD disallows running program that do this by default. Fix this. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14069> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11503: TypeError woes (incl. pattern match checker)
by GHC 01 Mar '19

01 Mar '19

#11503: TypeError woes (incl. pattern match checker) -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 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: -------------------------------------+------------------------------------- When I say {{{ {-# LANGUAGE DataKinds, GADTs, KindSignatures, TypeFamilies, UndecidableInstances #-} {-# OPTIONS_GHC -fwarn-incomplete-patterns #-} module Bug where import GHC.TypeLits import GHC.Exts ( Constraint ) type family NotInt a where NotInt Int = TypeError (Text "That's Int, silly.") NotInt _ = (() :: Constraint) data T a where MkT1 :: a -> T a MkT2 :: NotInt a => T a foo :: T Int -> Int foo (MkT1 x) = x }}} I get {{{ Bug.hs:19:1: warning: Pattern match(es) are non-exhaustive In an equation for ‘foo’: Patterns not matched: MkT2 }}} But I shouldn't. Even worse, perhaps, GHC accepts my pattern-match against `MkT2` if I add it. If I change the `TypeError` to `False ~ True`, I get the correct behavior. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11503> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16199: GHC 8.6's bundled version of transformers doesn't correspond to a Hackage release
by GHC 01 Mar '19

01 Mar '19

#16199: GHC 8.6's bundled version of transformers doesn't correspond to a Hackage release -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: Component: libraries | Version: 8.6.3 (other) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #14678 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- GHC 8.6 claims to be bundled with `transformers-0.5.5.0`, but this isn't true. That's because it's using transformers commit https://gitlab.haskell.org/ghc/packages/transformers/tree/80557845cdc0e72bc05cec19cf7a1bf5495e9e69, which happened //after// the commit corresponding to the Hackage release of 0.5.5.0 (https://gitlab.haskell.org/ghc/packages/transformers/commit/33b3c8a71778ae3…) This is not the first time this has happened: see #14678. While we were able to catch #14678 before a major release was shipped, but unfortunately, that didn't happen this time. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16199> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15641: Git repositories have several problems
by GHC 01 Mar '19

01 Mar '19

#15641: Git repositories have several problems -------------------------------------+------------------------------------- Reporter: flip101 | Owner: hvr Type: bug | Status: new Priority: high | Milestone: Component: Trac & Git | Version: 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 have some problems with the repositories. When i try to clone from the official repo: {{{ » git clone --single-branch --branch master --depth=1 --recursive git://git.haskell.org/ghc.git ghc-head Cloning into 'ghc-head'... fatal: The remote end hung up unexpectedly fatal: early EOF fatal: index-pack failed }}} Maybe it's because the git server version is old (1.9.1). Without `--depth=1` it works, but anyway it's an issue. With the github mirror i have another problem: {{{ Cloning into 'libraries/Cabal'... fatal: remote error: ghc/packages/Cabal is not a valid repository name Email support(a)github.com for help fatal: clone of 'git://github.com/ghc/packages/Cabal.git' into submodule path 'libraries/Cabal' failed }}} With the phabricator repo the following issue: command: {{{ git clone --depth=1 --single-branch --branch ghc-8.6 --recursive https://phabricator.haskell.org/diffusion/GHC/glasgow-haskell-compiler.git ghc-8.6-head }}} error: {{{ Cloning into '.arc-linters/arcanist-external-json-linter'... error: RPC failed; HTTP 503 curl 22 The requested URL returned error: 503 first byte timeout fatal: The remote end hung up unexpectedly fatal: clone of 'https://phabricator.haskell.org/diffusion/GHC/arcanist- external-json-linter.git' into submodule path '.arc-linters/arcanist- external-json-linter' failed }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15641> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16015: git notes logic breaks CircleCI validation of pull requests
by GHC 01 Mar '19

01 Mar '19

#16015: git notes logic breaks CircleCI validation of pull requests -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.6.3 Component: Compiler | Version: 8.6.2 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: -------------------------------------+------------------------------------- Due to missing credentials. David, can you have a look? https://circleci.com/gh/ghc/ghc/12493 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16015> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15800: Overlapping instances error with single instance
by GHC 01 Mar '19

01 Mar '19

#15800: Overlapping instances error with single instance -------------------------------------+------------------------------------- Reporter: roland | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{ {-# LANGUAGE MultiParamTypeClasses, FlexibleContexts, FlexibleInstances #-} module Bug where class C a b instance C a Int x :: () x = undefined :: C a Int => () }}} {{{ ghc -c Bug.hs Bug.hs:10:18: error: • Overlapping instances for C a0 Int Matching givens (or their superclasses): C a Int bound by an expression type signature: forall a. C a Int => () at Bug.hs:10:18-30 Matching instances: instance C a Int -- Defined at Bug.hs:7:10 (The choice depends on the instantiation of ‘a0’) • In the ambiguity check for an expression type signature To defer the ambiguity check to use sites, enable AllowAmbiguousTypes In an expression type signature: C a Int => () In the expression: undefined :: C a Int => () | 10 | x = undefined :: C a Int => () | ^^^^^^^^^^^^^ }}} The "matching instances" bit of the error messages only lists a single instance. Doesn't it take at least two instances for something to overlap? Also, following the algorithm laid out in the user guide (section "Overlapping Instances"), it appears this program should be accepted. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15800> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #16020: Hadrian: correctly Install libffi shared object files
by GHC 01 Mar '19

01 Mar '19

#16020: Hadrian: correctly Install libffi shared object files -------------------------------------+------------------------------------- Reporter: davide | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.6.3 Component: Build System | Version: 8.6.2 (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: -------------------------------------+------------------------------------- In Phab:D5423 a hack to correctly install the libffi .so files is implemented. This is a quick and dirty solution to fix the hadrian build. Note [Hadrian: install libffi hack] from that patch and also issue #15837 have more details, but ultimately hadrian should not have a special case for libffi. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16020> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14109: GHC matches -- as a varsym when lexing a qvarsym
by GHC 28 Feb '19

28 Feb '19

#14109: GHC matches -- as a varsym when lexing a qvarsym -------------------------------------+------------------------------------- Reporter: glguy | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 (Parser) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Other Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- GHC seems only to exclude the line comment marker `--` when lexing a varsym and not a qvarsym. This can be observed in the following code {{{ module Demo where x Demo.-- y = (x,y) }}} Generating this surprising error message {{{ /Users/emertens/Desktop/Demo.hs:3:3: error: Qualified name in binding position: Demo.-- }}} and excludes this definition perhaps? {{{ example f = Just.-- comment f }}} Which might either have lexed as `Just` `.` `-- comment`, or it might have lexed as `Just.-` `-`, but it probably shouldn't be the case that it's a qvarsym. At a minimum, the Haskell Report specifically excludes `--` from the varsym rule, so it can't support the qvarsym rule match that it is now. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14109> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9121: Presence of dyn_o files not checked? upon recompilation
by GHC 28 Feb '19

28 Feb '19

#9121: Presence of dyn_o files not checked? upon recompilation ------------------------------------+------------------------------------- Reporter: andreas.abel | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Build System | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- When I interrupt a compilation (initiated with cabal), and then recompile (with cabal), it can happen that gcc fails with missing .dyn_o file. I have "shared:True" in my .cabal/config file. [I can of course do cabal clean to work around, but since a full recompilation is about 10 min, I try to avoid this.] time cabal install --disable-library-profiling --disable-documentation Resolving dependencies... In order, the following will be installed: Agda-2.3.3 (latest: 2.3.2.2) (reinstall) Warning: Note that reinstalls are always dangerous. Continuing anyway... Configuring Agda-2.3.3... Building Agda-2.3.3... Preprocessing library Agda-2.3.3... [116 of 273] Compiling Agda.TypeChecking.Monad.Base[boot] ( src/full/Agda/TypeChecking/Monad/Base.hs-boot, dist/build/Agda/TypeChecking/Monad/Base.o-boot ) ... [239 of 273] Compiling Agda.TypeChecking.Conversion ( src/full/Agda/TypeChecking/Conversion.hs, dist/build/Agda/TypeChecking/Conversion.o ) [Agda.Syntax.Translation.InternalToAbstract changed] ^Cmake: *** [install-bin] Interrupt time cabal install --disable-library-profiling --disable-documentation Resolving dependencies... In order, the following will be installed: Agda-2.3.3 (latest: 2.3.2.2) (reinstall) Warning: Note that reinstalls are always dangerous. Continuing anyway... Configuring Agda-2.3.3... Building Agda-2.3.3... Preprocessing library Agda-2.3.3... [116 of 273] Compiling Agda.TypeChecking.Monad.Base[boot] ( src/full/Agda/TypeChecking/Monad/Base.hs-boot, dist/build/Agda/TypeChecking/Monad/Base.o-boot ) ... [273 of 273] Compiling Agda.Main ( src/full/Agda/Main.hs, dist/build/Agda/Main.o ) [Agda.Compiler.Epic.Compiler changed] gcc: error: dist/build/Agda/TypeChecking/Conversion.dyn_o: No such file or directory Failed to install Agda-2.3.3 cabal: Error: some packages failed to install: Agda-2.3.3 failed during the building phase. The exception was: ExitFailure 1 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9121> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15869: Discrepancy between seemingly equivalent type synonym and type family
by GHC 27 Feb '19

27 Feb '19

#15869: Discrepancy between seemingly equivalent type synonym and type family -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.6.2 (Type checker) | Keywords: TypeFamilies | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Consider the following code: {{{#!hs {-# LANGUAGE DataKinds #-} {-# LANGUAGE ImpredicativeTypes #-} {-# LANGUAGE PolyKinds #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE TypeInType #-} module Bug where import Data.Kind type KindOf1 (a :: k) = k type family KindOf2 (a :: k) :: Type where KindOf2 (a :: k) = k data A (a :: Type) :: a -> Type type family Apply1 (f :: KindOf1 A) (a :: Type) (x :: a) :: Type where Apply1 f a x = f a x }}} `Apply1` kind-checks, which is just peachy. Note that `Apply1` uses `KindOf1`, which is a type synonym. Suppose I wanted to swap out `KindOf1` for `KindOf2`, which is (seemingly) an equivalent type family. I can define this: {{{#!hs type family Apply2 (f :: KindOf2 A) -- (f :: forall a -> a -> Type) (a :: Type) (x :: a) :: Type where Apply2 f a x = f a x }}} However, GHC rejects this! {{{ $ /opt/ghc/8.6.2/bin/ghc Bug.hs [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) Bug.hs:25:10: error: • Expecting two more arguments to ‘f’ Expected kind ‘KindOf2 A’, but ‘f’ has kind ‘* -> a -> *’ • In the first argument of ‘Apply2’, namely ‘f’ In the type family declaration for ‘Apply2’ | 25 | Apply2 f a x = f a x | ^ }}} I find this quite surprising, since I would have expected `KindOf1` and `KindOf2` to be functionally equivalent. Even providing explicit `forall`s does not make it kind-check: {{{#!hs type family Apply2 (f :: KindOf2 A) -- (f :: forall a -> a -> Type) (a :: Type) (x :: a) :: Type where forall (f :: KindOf2 A) (a :: Type) (x :: a). Apply2 f a x = f a x }}} Although the error message does change a bit: {{{ $ ~/Software/ghc3/inplace/bin/ghc-stage2 Bug.hs [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) Bug.hs:26:20: error: • Expected kind ‘* -> a -> *’, but ‘f’ has kind ‘KindOf2 A’ • In the type ‘f a x’ In the type family declaration for ‘Apply2’ | 26 | Apply2 f a x = f a x | ^^^^^ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15869> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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