August 2016 - ghc-tickets

[GHC] #11736: Allow unsaturated uses of unlifted types in Core
by GHC 19 Jan '17

19 Jan '17

#11736: Allow unsaturated uses of unlifted types in Core -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: feature | Status: new request | Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 8.1 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: -------------------------------------+------------------------------------- Currently Core Lint checks for unsaturated uses of unlifted types in . These are easily produced in the new type-indexed `Typeable` scheme. For instance, consider solving for `Typeable # (Array# Int)`: * We decompose the application into wanteds `Typeable (* -> #) Array#` and `Typeable * Int` * We construct dictionaries for both, giving us a term `typeRepArray# :: TypeRep (* -> #) Array#` While nothing seems to blow up with this patch, {{{#!patch diff --git a/compiler/coreSyn/CoreLint.hs b/compiler/coreSyn/CoreLint.hs index 99625c9..2c401de 100644 --- a/compiler/coreSyn/CoreLint.hs +++ b/compiler/coreSyn/CoreLint.hs @@ -1040,7 +1040,7 @@ lintType ty@(TyConApp tc tys) = lintType ty' -- Expand type synonyms, so that we do not bogusly complain -- about un-saturated type synonyms - | isUnliftedTyCon tc || isTypeSynonymTyCon tc || isTypeFamilyTyCon tc + | isTypeSynonymTyCon tc || isTypeFamilyTyCon tc -- Also type synonyms and type families , length tys < tyConArity tc = failWithL (hang (text "Un-saturated type application") 2 (ppr ty)) }}} I otherwise have no reason to believe that this is safe. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11736> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11789: Flag suggestion does not always work
by GHC 18 Jan '17

18 Jan '17

#11789: Flag suggestion does not always work -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Driver | Version: 8.1 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: -------------------------------------+------------------------------------- Usually, GHC is very helpfully telling me about misspelled flags, but sometimes it fails. Did not yet look deeper, but when I wrote `-fppr- cols=1000` it did not suggest `-dppr-cols=1000`. I am not sure if this is due to the `=` or whether it branches on `-f` vs. `-d` earlier. This surely can be improved! Likely newcomer-friendly.. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11789> 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 16 Jan '17

16 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] #12090: Document Weverything/Wall/Wextra/Wdefault in user's guide
by GHC 13 Jan '17

13 Jan '17

#12090: Document Weverything/Wall/Wextra/Wdefault in user's guide -------------------------------------+------------------------------------- Reporter: hvr | Owner: hvr Type: task | Status: new Priority: normal | Milestone: 8.0.2 Component: Documentation | Version: 8.0.1 Keywords: warnings | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: Design/Warnings -------------------------------------+------------------------------------- The user's guide needs to be updated to reflect the feature implemented in phab:D1850 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12090> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11695: On GHCi prompt the arrow (movement) keys create strange character sequences
by GHC 12 Jan '17

12 Jan '17

#11695: On GHCi prompt the arrow (movement) keys create strange character sequences --------------------------------------+--------------------------------- Reporter: heisenbug | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 8.1 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+--------------------------------- Fire up `GHCi` and sit on the arrow down (or left) keys. This is what I get after constantly pressing for some time: {{{ $ ghci GHCi, version 8.1.20160202: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/ggreif/.ghci Prelude> OBOBOBBOBOBOBOBOBOBOBCOCCOCOCCOCCOC <interactive>:1:1: error: Data constructor not in scope: OBOBOBBOBOBOBOBOBOBOBCOCCOCOCCOCCOC }}} When such a strange letter appears, there is also a blinking of the terminal. It is not happening on Windows. I have seen it on RHEL5 and RHEL6. Pretty annoying, especially when you want to quickly navigate in the repl. This is probably a `haskeline` bug, but I am coming here to see whether others suffer from it too, i.e. is it reproducible for elseone? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11695> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11781: Improve common sub-expression
by GHC 12 Jan '17

12 Jan '17

#11781: Improve common sub-expression -------------------------------------+------------------------------------- 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): Phab:D2074 | Wiki Page: -------------------------------------+------------------------------------- I wrote a patch that refactors and improves the CSE pass. It's in `wip/cse-code-desmelling`, and Phab:D2074 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11781> 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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