February 2016 - ghc-tickets

[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] #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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[GHC] #10073: Idris REPL is pretty and we can too
by GHC 14 Jan '17

14 Jan '17

#10073: Idris REPL is pretty and we can too -------------------------------------+------------------------------------- Reporter: bitemyapp | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.8.4 Component: GHCi | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Manual for configuring colors in the Idris REPL: https://github.com/idris- lang/Idris-dev/wiki/Manual#colours Screenshot: http://i.imgur.com/rYHCI4T.png Particularly, I'd like to make type errors and warnings more visually distinct. I think little touches like this can go a long way to making it nice to work with Haskell code. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10073> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10083: ghc: panic! (the 'impossible' happened)
by GHC 12 Jan '17

12 Jan '17

#10083: ghc: panic! (the 'impossible' happened) -------------------------------------+------------------------------------- Reporter: hedayaty | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.4 Keywords: | Operating System: MacOS X Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- I used hprotoc to generate some code for Google protocol buffers. The QueryValue.proto file is attached. You can install hprotoc tool using cabal. then use ''hprotoc QueryValue.proto'' to generate code. Then create a minimal cabal file. ''cabal init -m --is-library -n'' Then if you build it with '''optimization enabled''', the build will fail ghc: panic! (the 'impossible' happened) (GHC version 7.8.3 for x86_64-apple-darwin): Simplifier ticks exhausted When trying UnfoldingDone $j_sEMq{v} [lid] To increase the limit, use -fsimpl-tick-factor=N (default 100) If you need to do this, let GHC HQ know, and what factor you needed To see detailed counts use -ddump-simpl-stats Total ticks: 59242 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10083> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10262: Improve documentation of module signatures
by GHC 11 Jan '17

11 Jan '17

#10262: Improve documentation of module signatures -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: | Version: 7.11 Documentation | Operating System: Unknown/Multiple Keywords: backpack | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Out of curiosity, I read the bit in the user manual about the new module signatures, and I find the text a little confusing. Could those in the know clarify the points below in the manual? Thanks! * (typo) The first example refers to `String.hs`. I think you mean `Text.hs`. * Is there a way to use module signatures to deal with mutually recursive modules? The example with `TextSig` seems to require that both `Text` and `TextSig` are compiled before `A`. * Could you provide an example of specifying multiple signature/implementation pairs with `--make`? * The manual says that the dialect of Haskell used in signature files is "essentially" the same as with hs-boot files. Are there any differences? * The most recent paragraph addition doesn't make sense to me, starting with "Signatures can be installed like ordinary modules". What do you mean by "installed"? What does it mean to bring multiple signatures into scope by the same name? Can two signatures have the same name? Wouldn't their filenames also need to be the same? * Is there currently any facility available to have multiple implementations of one signature? Of course, this is all work in progress, and I don't necessarily expect an immediate fix. But, when it's nearing completion, it may be worth revisiting this stretch of text. Thanks! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10262> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11592: Self-kinded type varialbe accepted
by GHC 10 Jan '17

10 Jan '17

#11592: Self-kinded type varialbe accepted -------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 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: -------------------------------------+------------------------------------- Found when chasing #11407 {{{ data T (a::a) = Blah -- Accepted data S (b :: a) a = ... -- Rejected with: variable ‘a’ used as a kind variable before being bound -- as a type variable. Perhaps reorder your variables? }}} But `T` should be rejected too, for the same reason as `S` -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11592> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11040: Split SRT tables on Mac OS
by GHC 10 Jan '17

10 Jan '17

#11040: Split SRT tables on Mac OS ----------------------------------------+--------------------------------- Reporter: olsner | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: MacOS X Architecture: Unknown/Multiple | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+--------------------------------- Split off from https://phabricator.haskell.org/D1242#inline-11490 Mac uses subsections via symbols to allow dead code stripping, but doesn't seem to do anything special with the SRT tables (in `HscMain.doCodeGen`), so either I'm missing something or Mac doesn't actually get much useful dead code stripping at all from the subsections feature because the SRT tables would keep everything alive. Perhaps Mac should just always do SRT splitting. Looks like you need to manually add `-optl-Wl,-dead_strip` to test this, since that's not enabled by default. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11040> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11551: Get doctests into testsuite
by GHC 10 Jan '17

10 Jan '17

#11551: Get doctests into testsuite -------------------------------------+------------------------------------- Reporter: lwm | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Core | Version: 7.10.3 Libraries | Keywords: | Operating System: Unknown/Multiple documentation, doctest | Architecture: | Type of failure: Documentation Unknown/Multiple | bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- It seems like a bit of a shame not to have Mr.Orlitzky's lovely doctests not running with the testsuite. Or perhaps to at least have some sort of `make doctest`. If there is some interest to get this working, I'd like to take a look at submitting a patch. Here are the previous documentation patches I can find: https://phabricator.haskell.org/p/mjo/ I can see the following files that have doctests: {{{ ruby-2.2.1 ~/work/contributing/ghc (master) [12:35:44] lwm$ grep -R "=== __Examples__" libraries/base/ | uniq grep: libraries/base/Data/Maybe.hs:-- ==== __Examples__ libraries/base/Data/Either.hs:-- ==== __Examples__ libraries/base/Data/List.hs:-- ==== __Examples__ libraries/base/Data/Functor.hs:-- ==== __Examples__ libraries/base/Data/Bool.hs:-- ==== __Examples__ libraries/base/Data/Char.hs:-- ==== __Examples__ libraries/base/GHC/Unicode.hs:-- ==== __Examples__ libraries/base/Text/Printf.hs:-- ==== __Examples__ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11551> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8761: Make pattern synonyms work with Template Haskell
by GHC 10 Jan '17

10 Jan '17

#8761: Make pattern synonyms work with Template Haskell ------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 7.8.1-rc1 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Template Haskell has no support for pattern synonyms. This should be added. Specifically: * Create syntax in `Language.Haskell.TH.Syntax` and corresponding functions in `Language.Haskell.TH.Lib` * Support in !DsMeta for desugaring pattern synonym quotations. See `rep_bind`. * Support in Convert for splicing in pattern synonyms. * Support in !TcSplice for reifying pattern synonyms. See `reifyThing`. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8761> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9748: Disambiguate IO actions in GHCi with :set +t
by GHC 06 Jan '17

06 Jan '17

#9748: Disambiguate IO actions in GHCi with :set +t -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: low | Milestone: Component: GHCi | Version: 7.8.2 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Easy (less than 1 | Type of failure: hour) | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Currently GHCi's `:set +t` displays the same type for the following: {{{#!hs % ghci -ignore-dot-ghci GHCi, version 7.8.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Prelude> :set +t Prelude> 'a' 'a' it :: Char Prelude> return 'a' 'a' it :: Char Prelude> return 'a' :: IO Char 'a' it :: Char }}} A user at `#haskell-beginners` ran into a problem where they mistook an expression that defaulted to IO for a pure expression (`Id . even <$> pure 5`), `:set +t` was suggested but ended up showing the incorrect type: {{{#!hs ghci> Id . even <$> pure 5 Id False it :: Id Bool }}} This is bad for pedagogical reasons, it would be an improvement to display the following: {{{#!hs Prelude> :set +t Prelude> 'a' 'a' it :: Char Prelude> return 'a' 'a' it :: Char <- return 'a' :: IO Char Prelude> return 'a' :: IO Char 'a' it :: Char <- return 'a' :: IO Char }}} mirroring existing syntax: {{{#!hs Prelude> :set -XScopedTypeVariables Prelude> a :: Char <- return 'a' :: IO Char a :: Char }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9748> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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