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Re: [GHC] #7867: Allow template-haskell to communicate with itself between compilation units through the interface file
by GHC 04 Oct '13

04 Oct '13

#7867: Allow template-haskell to communicate with itself between compilation units through the interface file --------------------------+------------------------------------------------ Reporter: errge | Owner: Type: | Status: patch feature request | Milestone: 7.8.1 Priority: | Version: 7.6.3 normal | Keywords: Component: | Architecture: Unknown/Multiple Template Haskell | Difficulty: Easy (less than 1 hour) Resolution: | Blocked By: 3725, 8337, 8340, 8397, 8398 Operating System: | Related Tickets: Unknown/Multiple | Type of failure: | None/Unknown | Test Case: | Blocking: | --------------------------+------------------------------------------------ Comment (by simonpj): errge, I've been talking to Austin It's very late in the day for 7.8, and we are still discussing the ''design''. So I don't think we can put this in 7.8, otherwise we'll mess it up and/or commit to a design that we subsequently regret. Can you start a GHC Trac wiki page to describe clearly * The use-case you have in mind. Along the lines you have given recently in #8337, but can you give a small concrete example? I still don't get it; for example, is `tcp_connect_timeout` exported, and if not what good is it? * The programmer's-eye view of the design (eg the TH API changes). For example, I'm very dubious about `qReifyModules` because the notion of the "list of modules that are known to the compiler" is such an ill-defined one. Imagine if you were writing a new Haskell compiler: how would you implement that API? What is its actual semantics? * A sketch of the implementation changes needed (and links to tickets) That would help more people participate in the conversation. At the moment you are implementing solutions to problems that we don't understand! Thanks Simon -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7867#comment:12> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7730: :info and polykinds
by GHC 04 Oct '13

04 Oct '13

#7730: :info and polykinds --------------------------------------------+------------------------------ Reporter: monoidal | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.8.1 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: --------------------------------------------+------------------------------ Comment (by simonpj): By default I'm now suppressing the kind arguments. But the problem is still there, as you'll see if you use `-fprint-explicit-kinds`. The trouble is that it's hard to build the `TyCon`s with pretty kind varaibles. When converting to `IfaceSyn` we do pretty-ify them (because interface files work on `OccNames`). So a viable approach would be, in the `info` command, to convert to `IfaceSyn` (using the existing code in `MkIface`) and then print that. I think this would be quite straightforward, but the printing stuff used by GHCi would need to be adapted to use `IfaceSyn` instead. Would anyone care to try this? Simple but a bit fiddly. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7730#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #6084: Add stg_ap_pnnv and related call patterns
by GHC 04 Oct '13

04 Oct '13

#6084: Add stg_ap_pnnv and related call patterns -------------------------------------+------------------------------------ Reporter: SimonMeier | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.8.1 Component: Runtime System | Version: 7.4.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: 8313 | Related Tickets: -------------------------------------+------------------------------------ Changes (by simonpj): * cc: simonmar (added) Comment: Simon M and I have agreed to commit this patch. However, there are times when we KNOW that the runtime fast-patch check will fail: {{{ f x y = e foo = ...map (f 3).... }}} In `foo` we'll generate a `SlowCall` to `f`, and there is no point in doing a runtime evaluated-ness and arity check on `f` because we can see statically that it's under-saturated. (Indeed ideally we'd have a RTS entry for known-under-saturated calls.) Or maybe we never ''have'' under- saturated known functions, because core-to-STG eta-expands it. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/6084#comment:15> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #2184: if findExecutable finds a file that matchs the argument, check if it is an executable
by GHC 04 Oct '13

04 Oct '13

#2184: if findExecutable finds a file that matchs the argument, check if it is an executable -------------------------------------+------------------------------------- Reporter: iago | Owner: leroux Type: bug | Status: patch Priority: high | Milestone: 7.8.1 Component: | Version: 6.8.2 libraries/directory | Keywords: findExecutable Resolution: | check executable Operating System: Linux | Architecture: x86 Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------- Changes (by simonpj): * priority: normal => high * milestone: 7.6.2 => 7.8.1 Comment: I know nothing about this, but I'll milestone it for 7.8.1 so that Austin is sure to review it. Austin: I'm not expressing an opinion, but could you look at this since we have a patch offered? Simon -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2184#comment:17> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8133: T7881 fails with hpc
by GHC 03 Oct '13

03 Oct '13

#8133: T7881 fails with hpc ----------------------------------+-------------------------- Reporter: jstolarek | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Code Coverage | Version: 7.7 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: Other Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+-------------------------- I noticed that T7881 fails with `hpc` way. I investigated a bit and I noticed that if I compile the program without hpc it emits 3 warnings (which is intended): {{{ [t-jastol@cam-05-unx : /5playpen/t-jastol/ghc- validate2/testsuite/tests/numeric/should_compile] '/5playpen/t-jastol/ghc- validate2/inplace/bin/ghc-stage2' -fforce-recomp -c T7881.hs -O T7881.hs:7:6: Warning: Enumeration is empty T7881.hs:25:6: Warning: Enumeration is empty T7881.hs:31:6: Warning: Enumeration is empty }}} But if I add `-fhpc` on the command line the warnings disappear: {{{ [t-jastol@cam-05-unx : /5playpen/t-jastol/ghc- validate2/testsuite/tests/numeric/should_compile] '/5playpen/t-jastol/ghc- validate2/inplace/bin/ghc-stage2' -fforce-recomp -c T7881.hs -O -fhpc [t-jastol@cam-05-unx : /5playpen/t-jastol/ghc- validate2/testsuite/tests/numeric/should_compile] }}} That's the reason why this test fails (mismatch of stderr). I don't know whether this is expected behaviour of hpc or not. If the former, then test configuration should be fixed, if the latter then hpc itself should be fixed. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8133> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7602: Threaded RTS performing badly on recent OS X (10.8?)
by GHC 03 Oct '13

03 Oct '13

#7602: Threaded RTS performing badly on recent OS X (10.8?) -----------------------------------+---------------------------------- Reporter: simonmar | Owner: thoughtpolice Type: bug | Status: new Priority: highest | Milestone: 7.8.1 Component: Runtime System | Version: 7.7 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: 7678 Blocking: | Related Tickets: -----------------------------------+---------------------------------- Changes (by george.colpitts): * cc: george.colpitts@…, simonmar (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7602#comment:28> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8368: Panic in rejigConRes
by GHC 03 Oct '13

03 Oct '13

#8368: Panic in rejigConRes ------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.7 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- When I compile the following erroneous code {{{ {-# LANGUAGE DataKinds, TypeFamilies, GADTs #-} import GHC.TypeLits data Foo = Bar data instance Sing (n :: Foo) where SBar :: Sing Foo }}} I get {{{ *** Exception: compiler/typecheck/TcTyClsDecls.lhs:1266:5-62: Irrefutable pattern failed for pattern Data.Maybe.Just subst }}} I think this is my fault. I will fix. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8368> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8390: regression in handling of type variables in constraints on instances which do not appear in the instance head
by GHC 03 Oct '13

03 Oct '13

#8390: regression in handling of type variables in constraints on instances which do not appear in the instance head ----------------------------+---------------------------------------------- Reporter: aavogt | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.7 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: GHC rejects valid program Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | ----------------------------+---------------------------------------------- ghc-7.7.20130720 (from here http://darcs.haskell.org/ghcBuilder/uploads/igloo-m/) rejects instances which work with ghc-7.6.2. {{{ {-# LANGUAGE FlexibleInstances, ImplicitParams, MultiParamTypeClasses, ScopedTypeVariables, TypeFamilies, UndecidableInstances #-} class Fun f a b where fun :: f -> a -> b instance (b ~ Int, a ~ Int) => Fun F a b where fun _ = (+1) data F = F data Compose a b = Compose a b -- ghc-7.6 version instance (Fun f b c, Fun g a b) => Fun (Compose f g) a c where fun (Compose f g) a = fun f (fun g a :: b) {- | ghc >= 7.7 accepts this second instance, which is an ugly workaround >>> fun (Compose F F) 2 4 unsatisfactory ghc-77 workaround: >>> let ?b = undefined in fun (Compose F F) 2 4 -} instance (Fun f b c, Fun g a b, ?b :: b) => Fun (Compose f g) a c where fun (Compose f g) a = fun f (fun g a `asTypeOf` ?b) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8390> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8357: Pretty printing of kind-involving inferred types
by GHC 03 Oct '13

03 Oct '13

#8357: Pretty printing of kind-involving inferred types ------------------------------------+------------------------------------- Reporter: ksf | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.7 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- An example of inferred types (foo, bar, both), for brevity's sake omitting value-level details: {{{ {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE DataKinds #-} {-# LANGUAGE KindSignatures #-} {-# LANGUAGE TypeOperators #-} import GHC.TypeLits data (:::) (sy :: Symbol) ty data Key (sy :: Symbol) data Rec (rs :: [*]) (*=) :: Key sy -> ty -> Rec '[sy ::: ty] (*=) = undefined (.*.) :: (Union xs ys ~ rs) => Rec xs -> Rec ys -> Rec rs (.*.) = undefined type family Union (xs :: [*]) (ys :: [*]) :: [*] where Union ((sy ::: t) ': xs) ys = (sy ::: t) ': Union xs ys Union '[] ys = ys fFoo :: Key "foo" fFoo = undefined fBar :: Key "bar" fBar = undefined foo :: Rec ((':) * ("foo" ::: [Char]) ('[] *)) foo = fFoo *= "foo" bar :: Rec ((':) * ("bar" ::: [Char]) ('[] *)) bar = fBar *= "bar" both :: Rec ((':) * ("foo" ::: [Char]) ((':) * ("bar" ::: [Char]) ('[] *))) both = foo .*. bar }}} There's actually two issues, here: First, the most serious one, GHC prints kind annotations (*) that it can't even parse back, and then [*] types are pretty printed with ': constructors instead of nicely with [,] syntax. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8357> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8384: -fwarn-empty-enumerations doesn't work with -fhpc
by GHC 03 Oct '13

03 Oct '13

#8384: -fwarn-empty-enumerations doesn't work with -fhpc ------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.7 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- It appears that tick insertion occurs before arithmetic sequences are desugared, so `warnAboutEmptyEnumerations` can't see the calls to `fromInteger`, because they have been wrapped in ticks already. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8384> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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