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Re: [GHC] #4479: Implement TDNR
by GHC 10 Jun '16

10 Jun '16

#4479: Implement TDNR -------------------------------------+------------------------------------- Reporter: gidyn | Owner: Type: feature request | Status: new Priority: low | Milestone: Component: Compiler (Type | Version: 7.5 checker) | Resolution: | Keywords: ORF Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by adamgundry): * keywords: => ORF Comment: gidyn, thanks for starting a new proposal. Your effort to push this along is appreciated! I think your idea for doing TDNR without any syntax can indeed be seen as a proper generalization of `DuplicateRecordFields`, which permits syntaxless TDNR in the special case of record field names. Unfortunately I tend to agree with AntC that the proposal needs more precision. We want to avoid the situation that the programs GHC accepts depend on implementation details of the type-checker. This means that we need a (possibly hypothetical) declarative specification of what the typing rules should be for ambiguous names. Moreover, it's probably best if introducing or removing an ambiguity doesn't lead to different valid types for the same program. This implies that disambiguation should use information gleaned from the existing bidirectional typing rules, but not do additional inference. This requirement is why approaches based on deferring name resolution to the constraint solver, like ORF's magic classes, use a syntactic cue to indicate that the identifier should be treated specially. These are tough goals to meet, and explain why the current `DuplicateRecordFields` is quite conservative in what it will accept (see #11343). No doubt it is possible to do something more general, but it's hard to specify, let alone implement. I think that is part of the reason that TDNR has languished over the years. [AntC already mentioned this on the wiki page, but for future reference, this mailing list thread is very relevant: https://mail.haskell.org/pipermail/glasgow-haskell- users/2016-May/026225.html] -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4479#comment:32> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12003: Improve error message about closed variables
by GHC 10 Jun '16

10 Jun '16

#12003: Improve error message about closed variables -------------------------------------+------------------------------------- Reporter: | Owner: facundo.dominguez | Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple StaticPointers | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #11656 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- After allowing local bindings in static definitions the following program {{{ {-# LANGUAGE StaticPointers #-} module M where f x = static g where g = h h = x }}} yields the error {{{ ../tmp/M.hs:4:7: error: • ‘g’ is used in a static form but it is not closed. • In the expression: static g In an equation for ‘f’: f x = static g where g = h h = x }}} Where it would be more helpful to get a message like {{{ ../tmp/M.hs:4:7: error: • ‘g’ is used in a static form but it is not closed because it uses ‘h’ which uses ‘x’ which is not let-bound. • In the expression: static g In an equation for ‘f’: f x = static g where g = h h = x }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12003> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 09 Jun '16

09 Jun '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"77b8c29b8baf9b84df6c8352d7f785c75522eff4/ghc" 77b8c29/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="77b8c29b8baf9b84df6c8352d7f785c75522eff4" Remove Ord AltCon It uses Ord DataCon which uses Ord Unique which is nondeterministic GHC Trac: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:207> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12014: Make it possible to deprecate a method instantiation of a typeclass instance
by GHC 09 Jun '16

09 Jun '16

#12014: Make it possible to deprecate a method instantiation of a typeclass instance -------------------------------------+------------------------------------- Reporter: niteria | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 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: {{{ module A where data Foo = Foo instance Eq Foo where -- {-# DEPRECATED (==) "Deprecated for no reason as well" #-} _a == _b = True {-# DEPRECATED (==.) "Deprecated for no reason" #-} (==.) :: Foo -> Foo -> Bool (==.) _a _b = True }}} Deprecating `(==.)` is possible, but it's not possible to deprecate `(==)` of the `Eq Foo` instance. I'd be useful for my use-case of finding out where `Ord Unique` is used, as these would be a potential sources of non-determinism. Currently the best I can do is to remove the instance, get a compile error, suppress it by fixing up the code and repeat for every affected file. I imagine it would also be useful if a method turned out to be a bad idea for a particular type and the library author tried to phase it out. It could be that one method is implementable, but has terrible performance. For my use-case I would be happy with instance level granularity. Related (but not quite the same): * https://ghc.haskell.org/trac/ghc/wiki/Design/DeprecationMechanisms#Classmet… * https://ghc.haskell.org/trac/ghc/wiki/Design/DeprecationMechanisms/TypeClas… -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12014> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 09 Jun '16

09 Jun '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by niteria): Replying to [comment:198 nomeata]: > You are doing such great work that I regret having commented on this bug before, as now I get spanned by mails about this ticket! > > Keep up the good work :-) Yeah, sorry about the spam. I have lots of small changes that it wouldn't make sense to bundle together. I also want them attached to this ticket, so I can track the needed patches. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:206> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 09 Jun '16

09 Jun '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"b2624ee3efe847d553a9a8b822f88ff5bb056377/ghc" b2624ee3/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="b2624ee3efe847d553a9a8b822f88ff5bb056377" Remove Ord PatSyn It's implemented in terms of Unique which is nondeterministic GHC Trac: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:205> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 09 Jun '16

09 Jun '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"70e0a5644b8c20f70d6349cb4e0a0f0f1c06f5a0/ghc" 70e0a56/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="70e0a5644b8c20f70d6349cb4e0a0f0f1c06f5a0" Remove Ord Class It was implemented in terms of Unique which is nondeterministic GHC Trac: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:204> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 09 Jun '16

09 Jun '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"68c1c29d9c43a22a5cbd34fd67b7c543ede17eac/ghc" 68c1c29d/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="68c1c29d9c43a22a5cbd34fd67b7c543ede17eac" Remove Ord (CoAxiom br) It was implemented in terms of Uniques, but fortunately it's unused so we can remove it. GHC Trac: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:203> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 09 Jun '16

09 Jun '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"ceaf7f10865cd27eaa16a5e1fd308799c00e0607/ghc" ceaf7f10/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="ceaf7f10865cd27eaa16a5e1fd308799c00e0607" Implement Eq TyCon directly Eq TyCon is defined in terms of Ord TyCon, but we want to remove Ord TyCon, because it's implemented in terms of unique comparison, which is nondeterministic. GHC Trac: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:202> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5642: Deriving Generic of a big type takes a long time and lots of space
by GHC 09 Jun '16

09 Jun '16

#5642: Deriving Generic of a big type takes a long time and lots of space -------------------------------------+------------------------------------- Reporter: basvandijk | Owner: bgamari Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.3 Resolution: | Keywords: deriving- | perf, Generics Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: T5642 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2304 Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * cc: bgamari (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5642#comment:40> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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