April 2014 - ghc-tickets

Re: [GHC] #3927: Incomplete/overlapped pattern warnings + GADTs = inadequate
by GHC 16 Apr '14

16 Apr '14

#3927: Incomplete/overlapped pattern warnings + GADTs = inadequate -------------------------------------+------------------------------------ Reporter: simonpj | Owner: simonpj Type: bug | Status: new Priority: high | Milestone: 7.8.3 Component: Compiler | Version: 6.12.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: #4139 -------------------------------------+------------------------------------ Changes (by cactus): * cc: gergo@… (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3927#comment:32> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9006: Ship default bash completion file with ghc
by GHC 16 Apr '14

16 Apr '14

#9006: Ship default bash completion file with ghc ------------------------------------+------------------------------------- Reporter: td123 | Owner: Type: feature request | Status: new Priority: lowest | Milestone: Component: None | 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: | ------------------------------------+------------------------------------- Now that ticket #7843 has been closed, it would be great to ship a default implementation of a bash completion file for ghc. Since there isn't a standard location to install completion files across distros, it might be good to have an optional flag during configure to specify a location and if one is specified, install the bash completion file into that location. The following links provide implementations that have worked for me: http://www.reddit.com/r/haskell/comments/236qkb/autocomplete_command_line_o… https://ghc.haskell.org/trac/ghc/wiki/AutocompleteGHCFlags -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9006> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #3927: Incomplete/overlapped pattern warnings + GADTs = inadequate
by GHC 16 Apr '14

16 Apr '14

#3927: Incomplete/overlapped pattern warnings + GADTs = inadequate -------------------------------------+------------------------------------ Reporter: simonpj | Owner: simonpj Type: bug | Status: new Priority: high | Milestone: 7.8.3 Component: Compiler | Version: 6.12.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: #4139 -------------------------------------+------------------------------------ Comment (by cactus): I was asked about the following program failing to compile. Do you think this is also caused by the same underlying problem? {{{ {-# OPTIONS_GHC -fwarn-incomplete-patterns -Werror #-} {-# LANGUAGE GADTs, TypeFamilies #-} type family F a type instance F a = () data Foo a where FooA :: Foo () FooB :: Foo Int f :: a -> Foo (F a) -> () f _ FooA = () }}} The error/warning is, of course: {{{ gadt-incomplete.hs:12:1: Warning: Pattern match(es) are non-exhaustive In an equation for `f': Patterns not matched: _ FooB }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3927#comment:31> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4114: Add a flag to remove/delete intermediate files generated by GHC
by GHC 16 Apr '14

16 Apr '14

#4114: Add a flag to remove/delete intermediate files generated by GHC -------------------------------------+------------------------------------ Reporter: guest | Owner: iduhetonas Type: feature request | Status: new Priority: low | Milestone: 7.6.2 Component: Compiler | Version: 6.10.4 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: #2258 -------------------------------------+------------------------------------ Changes (by simonmic): * cc: simon@… (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4114#comment:13> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7730: :info and polykinds
by GHC 16 Apr '14

16 Apr '14

#7730: :info and polykinds --------------------------------------------+------------------------------ Reporter: monoidal | Owner: archblob Type: bug | Status: new Priority: normal | Milestone: 7.8.3 Component: Compiler (Type checker) | Version: 7.6.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: #8776 --------------------------------------------+------------------------------ Comment (by archblob): Regarding (2), currently ifAxiom just gets the name of the axiom, so as you say we could also get the name from the ``` TyCon ``` and other info we need, that's what I was working on now but it just doesn't feel right to add all that redundant information in there.```pprTyThing``` gets called on a family instance tycon because when we request info about a data constructor of a family instance we call ```tyThingParent_maybe``` that will return the immediate parent and in this case it is the family instance tycon. We could bypass this and instead return a ``` FamInst ``` in the appropriate case, like this we don't need to add any extra info to ``` IfaceData ```. ```tyThingParent_maybe``` is only used for pretty printing so if you think this is a good idea it will not complicate things ? Regarding the context printing properly I thought that needs no mentioning because you suggested how it should be fixed in another comment here and in #8876, I just wanted to get these other things right first. Andrei -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7730#comment:22> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7730: :info and polykinds
by GHC 16 Apr '14

16 Apr '14

#7730: :info and polykinds --------------------------------------------+------------------------------ Reporter: monoidal | Owner: archblob Type: bug | Status: new Priority: normal | Milestone: 7.8.3 Component: Compiler (Type checker) | Version: 7.6.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: #8776 --------------------------------------------+------------------------------ Comment (by simonpj): Re recursive flags, promotable, etc, the usual convention is to print that kind of stuff when `-dppr-debug` is enabled. Let's just do that for now. I was expecting you to say that a type like `Ord a => a -> Bool` is printing as `Ord a -> a -> Bool`, which isn't what the user of GHCi expects. Isn't that happening? To solvet hat I propose that we add a new constructor `IfaceDFunTy` to `IfaceType`, that behaves exactly like `IfaceFunTy` except that it prints differently. Re (2) that's an example of a bump in the road, and one I was expecting. I think it amounts to saying that the `ifAxiom` field of the `IfaceData` constructor doesn't have enough information to print nicely. One possibility is to add that information; it's kind of redundant (in the same way as `IfaceDFunTy`, but helps printing. But first, why are we calling `pprTyThing` on a family instance tycon? Does this case show up in practice? If so, how? I'd expect it to be more common to print a `IfaceFamInst`. Simon -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7730#comment:21> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7730: :info and polykinds
by GHC 16 Apr '14

16 Apr '14

#7730: :info and polykinds --------------------------------------------+------------------------------ Reporter: monoidal | Owner: archblob Type: bug | Status: new Priority: normal | Milestone: 7.8.3 Component: Compiler (Type checker) | Version: 7.6.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: #8776 --------------------------------------------+------------------------------ Comment (by archblob): Yeah, so regarding 1* from comment19, that was just me being very silly, I'll upload a patch that fixes that soon. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7730#comment:20> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9000: Kind checking fails when using PolyKinds
by GHC 15 Apr '14

15 Apr '14

#9000: Kind checking fails when using PolyKinds -------------------------------------+------------------------------------- Reporter: facundo.dominguez | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.8.2 checker) | Operating System: Linux Keywords: | Type of failure: GHC rejects Architecture: x86_64 (amd64) | valid program Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- GHC HEAD and earlier versions are failing on the following program: {{{ {-# LANGUAGE PolyKinds #-} import GHC.Exts(Any) f = (undefined :: a -> m a) :: Any -> Any Any }}} {{{ ../tmp/test-polykinds.hs:3:6: Couldn't match kind ‘k1’ with ‘*’ ‘k1’ is a rigid type variable bound by an expression type signature: Any -> Any Any at ../tmp/test-polykinds.hs:3:5 Expected type: Any -> Any Any Actual type: Any -> m0 Any In the expression: (undefined :: a -> m a) :: Any -> Any Any In an equation for ‘f’: f = (undefined :: a -> m a) :: Any -> Any Any }}} Rewriting the program as follows has compilation succeed. {{{ f = (undefined :: a -> m a) `asTypeOf` (undefined :: Any -> Any Any) }}} And removing the {{{PolyKinds}}} extension also has compilation succeed. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9000> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8882: internal error (deriving generic / cyclical imports?)
by GHC 15 Apr '14

15 Apr '14

#8882: internal error (deriving generic / cyclical imports?) ----------------------------------+------------------------------- Reporter: mf825 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: panic | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: GHCi crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+------------------------------- Hi everybody, I often get compiler crashes in my larger and less well-maintained projects of this sort: ghc: panic! (the 'impossible' happened) (GHC version 7.6.3 for x86_64-unknown-linux): tcIfaceGlobal (local): not found: <<details unavailable>> This happened on earlier 7.* ghc versions (debian 64bit), and from the counter-example I have condensed today my vague guess is that it has something to do with cyclical imports and -XDerivingGeneric or some other type system related language extension. I witnessed this in both ghc and ghci, but the counter-example is in ghci. I want to investigate this further later, but in the hope that somebody can immediately see what's wrong, I decided to open this ticket with my preliminary findings. Just unpack and run ./crash.sh. (Possibly you don't need to populate the sandbox and can crash it manually in your environment right away.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8882> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7744: Can't install conduit via cabal-install
by GHC 15 Apr '14

15 Apr '14

#7744: Can't install conduit via cabal-install ---------------------------------------+---------------------------------- Reporter: guest | Owner: Type: bug | Status: closed Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.6.3 Resolution: invalid | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: Compile-time crash | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------------+---------------------------------- Changes (by yezariaely): * status: new => closed * resolution: => invalid Comment: Just saw that this is of course not a ghc bug. Sorry. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7744#comment:4> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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