January 2017 - ghc-tickets

[GHC] #13148: Adding weak pointers to non-mutable unboxed values segfaults
by GHC 18 Jan '17

18 Jan '17

#13148: Adding weak pointers to non-mutable unboxed values segfaults -------------------------------------+------------------------------------- Reporter: mboes | 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: -------------------------------------+------------------------------------- Consider the following program: {{{#!hs {-# LANGUAGE MagicHash #-} {-# LANGUAGE UnboxedTuples #-} module Main where import Foreign import GHC.Base import GHC.IORef import GHC.Ptr import GHC.STRef import System.Mem main = do p@(Ptr p#) <- mallocBytes 10 r@(IORef (STRef r#)) <- newIORef True IO $ \s -> case mkWeakNoFinalizer# r# () s of (# s1, w #) -> (# s1, () #) performGC }}} This program works fine. But if I `mkWeakNoFinalizer#` to `#p` instead of `#r` then it '''segfaults'''. That is, I can attach a weak pointer to a `MutVar#`, as well as to a `MVar#`, but not any other unboxed type, including pointer addresses. The documentation says "Finalizers ''can'' be used reliably for types that are created explicitly and have identity, such as IORef and MVar". But a) I don't know that "types that have identity" is defined anywhere, b) this doesn't say that weak pointers ''cannot'' be used for anything else. Should I be able to create weak pointers to any unboxed value? If not, I guess this is mostly a documentation bug. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13148> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13107: Negative literal equal to minBound gives a spurious warning
by GHC 18 Jan '17

18 Jan '17

#13107: Negative literal equal to minBound gives a spurious warning -------------------------------------+------------------------------------- Reporter: erikd | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect Unknown/Multiple | error/warning at compile-time Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- In GHCi: {{{ λ > import GHC.Int λ > -128 :: Int8 <interactive>:25:2: warning: [-Woverflowed-literals] Literal 128 is out of the Int8 range -128..127 If you are trying to write a large negative literal, use NegativeLiterals -128 λ > minBound :: Int8 -128 }}} Since `-128 :: Int8` is equal to `minBound :: Int8` this warning is not correct. Similar issues exist for `Int16`, `Int32` etc. Suspect this is related to the fix for #8542. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13107> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13120: Can't compile HEAD with ghc-7.10.1
by GHC 17 Jan '17

17 Jan '17

#13120: Can't compile HEAD with ghc-7.10.1 -------------------------------------+------------------------------------- Reporter: Yuras | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Building GHC Unknown/Multiple | failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- (Yes, I'm still using `ghc-7.10.1` :) ) `compiler/util/Util.hs` exports `GHC.Stack.CallStack`, which is available since `7.10.2`. We can 1) drop older versions; 2) protect the export using `CPP`; 3) remove the export completely because it doesn't seem to be used anywhere. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13120> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7450: Regression in optimisation time of functions with many patterns (6.12 to 7.4)?
by GHC 17 Jan '17

17 Jan '17

#7450: Regression in optimisation time of functions with many patterns (6.12 to 7.4)? -------------------------------------+------------------------------------- Reporter: iustin | Owner: bgamari Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1012 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"b1726c1194f1ed35dffc83304260b3b29abd0c53/ghc" b1726c11/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="b1726c1194f1ed35dffc83304260b3b29abd0c53" Bitmap: Use foldl' instead of foldr These are producing StgWords so foldl' is the natural choice. I'm not sure how I didn't notice this when I wrote D1041. Test Plan: Validate Reviewers: austin, simonmar Reviewed By: simonmar Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2955 GHC Trac Issues: #7450 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7450#comment:34> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13111: maintainer-clean should clean build.mk
by GHC 17 Jan '17

17 Jan '17

#13111: maintainer-clean should clean build.mk -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: task | Status: new Priority: highest | Milestone: 8.2.1 Component: Build System | 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: -------------------------------------+------------------------------------- Unfortunately `maintainer-clean` doesn't clean `mk/build.mk`, which lead to bad binary distributions being distributed for 8.0.2. This needs to be fixed. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13111> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9137: A way to match RULES only for literals
by GHC 17 Jan '17

17 Jan '17

#9137: A way to match RULES only for literals ------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | 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: | ------------------------------------+------------------------------------- In `GHC/Enum` we have {{{ {-# RULES "enumDeltaToInteger1" [0] forall c n x . enumDeltaToIntegerFB c n x 1 = up_fb c n x 1 #-} -- This rule ensures that in the common case (delta = 1), we do not do the check here, -- and also that we have the chance to inline up_fb, which would allow the constructor to be -- inlined and good things to happen. -- We do not do it for Int this way because hand-tuned code already exists, and -- the special case varies more from the general case, due to the issue of overflows. }}} This rule would be useful for all literals, not just for `1`. I remember a discussion that such a rule would be more useful if we had a way to specify that, for example (random syntax). {-# RULES "enumDeltaToInteger1" [0] forall c n x d . isLiteral d => enumDeltaToIntegerFB c n x d = up_fb c n x d #-} I’m reporting this now to be able to link to it from #9136, where this feature might also help. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9137> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13139: Documents not updating correctly?
by GHC 16 Jan '17

16 Jan '17

#13139: Documents not updating correctly? -------------------------------------+------------------------------------- Reporter: lerkok | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Documentation | 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: -------------------------------------+------------------------------------- I noticed a few broken links in the user-guide. The papers linked in the recursive-do section here: http://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts… #the-mdo-notation are unfortunately outdated. (They moved elsewhere!) I was going to submit a git-hub patch to fix the links. After some digging, however, I found that someone else noticed the same about 8 months ago and fixed it already in this commit: http://github.com/ghc/ghc/commit/961ed26b69292f6bfb75cd2209ea0c67e77abf7b So, I'm wondering why the latest document doesn't seem to render the correct links, given this was fixed last May? Something off with the document builder? Did that commit somehow not make it into the rendered user-guide? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13139> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11140: add command-line option to GHC to dump raw parse trees of Haskell programs
by GHC 16 Jan '17

16 Jan '17

#11140: add command-line option to GHC to dump raw parse trees of Haskell programs -------------------------------------+------------------------------------- Reporter: bollu | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.10.2 Keywords: newcomer | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- As of now, GHC has no option to dump the parse tree of a given Haskell source file. `-ddump-parsed` only displays the pretty-printed AST structure, and cannot be used to inspect parse trees. An existing implementation of such a feature is present in apply- refact(https://github.com/mpickering/apply-refact) by invoking the tool as `refactor --debug`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11140> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #393: functions without implementations
by GHC 16 Jan '17

16 Jan '17

#393: functions without implementations -------------------------------------+------------------------------------- Reporter: c_maeder | Owner: Iceland_jack Type: feature request | Status: new Priority: normal | Milestone: ⊥ Component: Compiler (Type | Version: None checker) | Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): Used in [https://ghc.haskell.org/trac/ghc/attachment/ticket/13133/PrettyStub.hs code] attacked to tickets, module of stubs -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/393#comment:38> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13133: Real World Haskell SimpleJSON (initTc: unsolved constraints)
by GHC 16 Jan '17

16 Jan '17

#13133: Real World Haskell SimpleJSON (initTc: unsolved constraints) -------------------------------------+------------------------------------- Reporter: jboydt | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: MacOS X Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-apple-darwin): initTc: unsolved constraints WC {wc_insol = [W] hexEscape_a2tI :: t_a2tH[tau:1] (CHoleCan: hexEscape)} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13133> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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