June 2016 - ghc-tickets

Re: [GHC] #5642: Deriving Generic of a big type takes a long time and lots of space
by GHC 18 Jun '16

18 Jun '16

#5642: Deriving Generic of a big type takes a long time and lots of space -------------------------------------+------------------------------------- Reporter: basvandijk | Owner: bgamari Type: bug | Status: merge 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): * status: new => merge Comment: We might consider merging this for 8.0.2. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5642#comment:42> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9682: Implement "Add bifunctor related classes to base"-Proposal
by GHC 18 Jun '16

18 Jun '16

#9682: Implement "Add bifunctor related classes to base"-Proposal -------------------------------------+------------------------------------- Reporter: hvr | Owner: ekmett Type: task | Status: new Priority: normal | Milestone: 7.10.1 Component: Core Libraries | Version: Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Moderate (less | Type of failure: than a day) | None/Unknown Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- See [http://www.haskell.org/pipermail/libraries/2014-April/022844.html original libraries@ proposal] for more details -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9682> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10448: Implement rest of "Add bifunctor related classes to base"-Proposal
by GHC 18 Jun '16

18 Jun '16

#10448: Implement rest of "Add bifunctor related classes to base"-Proposal -------------------------------------+------------------------------------- Reporter: hvr | Owner: ekmett Type: task | Status: new Priority: normal | Milestone: 7.12.1 Component: | Version: libraries/base | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: #9682 Test Case: | Blocking: | Differential Revisions: Phab:D336 | -------------------------------------+------------------------------------- Cloned from #9682: ---- See [http://www.haskell.org/pipermail/libraries/2014-April/022844.html original libraries@ proposal] for more details -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10448> 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 18 Jun '16

18 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: | -------------------------------------+------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"9649fc0ae45e006c2ed54cc5ea2414158949fadb/ghc" 9649fc0a/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="9649fc0ae45e006c2ed54cc5ea2414158949fadb" Refactor derived Generic instances to reduce allocations Previously, derived implementations of `to`/`from` in `Generic` instances were wastefully putting extra `M1`s in every case, which led to an O(n) increase in the number of coercions, resulting in a slowdown during the typechecker phase. This factors out the common `M1` in every case of a `to`/`from` definition so that the typechecker has far fewer coercions to deal with. For a datatype with 300 constructors, this change has been observed to save almost 3 seconds of compilation time. This is one step towards coming up with a solution for #5642. Test Plan: ./validate Reviewers: hvr, austin, simonpj, bgamari Reviewed By: bgamari Subscribers: basvandijk, carter, thomie, osa1 Differential Revision: https://phabricator.haskell.org/D2304 GHC Trac Issues: #5642 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5642#comment:41> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12204: Weird import cycle when using plugins
by GHC 18 Jun '16

18 Jun '16

#12204: Weird import cycle when using plugins -------------------------------------+------------------------------------- Reporter: osa1 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 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: -------------------------------------+------------------------------------- Here's a demo: {{{ $ ghc Plugin.hs [1 of 1] Compiling Plugin ( Plugin.hs, Plugin.o ) $ ghc Main.hs [1 of 1] Compiling Main ( Main.hs, Main.o ) Linking Main ... $ rm Main.hi Main.o $ ghc Main.hs -fplugin=Plugin Module imports form a cycle: module ‘Plugin’ (./Plugin.hs) imports itself $ cat Plugin.hs module Plugin (plugin) where plugin = undefined $ cat Main.hs module Main (main) where main :: IO () main = return () }}} Tried with 8.0.1, HEAD. I don't know why installing plugins using Cabal works but this doesn't. I can't add plugin tests because of this. I can try fixing this myself if someone points me to the right direction -- I have no idea which part of the compiler could be doing this. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12204> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12197: test suite: implement a way to run tests with stage1 compiler
by GHC 18 Jun '16

18 Jun '16

#12197: test suite: implement a way to run tests with stage1 compiler -------------------------------------+------------------------------------- Reporter: osa1 | Owner: Type: task | Status: new 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: -------------------------------------+------------------------------------- In Phab:D2334, #10382 and probably other tickets/patches, we want to run some tests on compiler compiled with `GhcWithInterpreter=NO`. One way to do that is to run those tests with stage1 compiler, but current test runner doesn't give us a way to do that. We should add tests for Phab:D2334 (and probably for #10382) once this is implemented. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12197> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12192: ghc ../Test (without file extension) should work
by GHC 18 Jun '16

18 Jun '16

#12192: ghc ../Test (without file extension) should work -------------------------------------+------------------------------------- Reporter: thomie | Owner: thomie Type: bug | Status: new Priority: normal | Milestone: Component: Driver | 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: -------------------------------------+------------------------------------- This works: {{{ ghc Test ghc foo/Test }}} This doesn't work: {{{ ghc ../Test }}} With file `Test.hs` just containing `module Test where`. I have a fix. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12192> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10382: Template Haskell quotes should work with stage 1 compiler
by GHC 18 Jun '16

18 Jun '16

#10382: Template Haskell quotes should work with stage 1 compiler -------------------------------------+------------------------------------- Reporter: ezyang | Owner: ezyang Type: feature | Status: new request | Milestone: 7.12.1 Priority: normal | Version: 7.11 Component: Template | Operating System: Unknown/Multiple Haskell | Type of failure: None/Unknown Keywords: | Blocked By: Architecture: | Related Tickets: Unknown/Multiple | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Right now, you must enable the `TemplateHaskell` extension to use quotes, and `TemplateHaskell` is not supported by the stage 1 compiler. But there actually is no good reason why this should be the case: quoting doesn't require any user-written code to be loaded up and run, so it should be doable by the stage 1 compiler. I propose adding a new extension, `Quotation`, which turns on JUST quotation and works with the stage 1 compiler. This will solve len's problem https://github.com/ekmett/lens/issues/496 where they want to rename some syntax using quotation, but don't want break compilation on a stage 1 compiler. See also #10279. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10382> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5218: Add unpackCStringLen# to create Strings from string literals
by GHC 17 Jun '16

17 Jun '16

#5218: Add unpackCStringLen# to create Strings from string literals -------------------------------------+------------------------------------- Reporter: tibbe | Owner: thoughtpolice Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.0.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #5877 #10064 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonmar): Hmm, this seems a bit dodgy. The RULE is not semantics-preserving (deliberately, I know), so if you use `viewCString#` you get a non- deterministic result that depends on whether optimisation is turned on and whether the RULE fired. I suppose the idea is that you hide the non- determinism behind a layer of library code, but still, I'm not keen on having non-deterministic primitives. What's wrong with the approach in #10064 to have string literals of type `(# Int#, Addr# #)`? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5218#comment:38> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12202: GHC 7.10.3 throws away callstack frames for outer
by GHC 17 Jun '16

17 Jun '16

#12202: GHC 7.10.3 throws away callstack frames for outer -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 (Type checker) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Incorrect result Unknown/Multiple | at runtime Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- It was noticed that GHC 7.10.3 sometimes drops outer callers from IP callstacks. For instance, {{{#!hs {-# LANGUAGE ImplicitParams #-} import GHC.Stack import Control.Monad.Catch newtype MyError = MyError CallStack instance Exception MyError instance Show MyError where show (MyError e) = show e fromEvents :: (MonadThrow m, ?loc :: CallStack) => m (Maybe Int) fromEvents = do Just <$> require 42 where -- require :: (MonadThrow m, ?loc :: CallStack) => Int -> m Int require n -- line 17 | even n = throwM $ MyError ?loc | otherwise = return n main = do putStrLn "Hello world" fromEvents -- line 24 }}} GHC 8.0.1 produces the correct output, {{{ $ ./Hi Hello world Hi: [("fromEvents",SrcLoc {srcLocPackage = "main", srcLocModule = "Main", srcLocFile = "Hi.hs", srcLocStartLine = 24, srcLocStartCol = 5, srcLocEndLine = 24, srcLocEndCol = 15})] }}} GHC 7.10.3 produces only one {{{#!hs $ ./Hi Hello world Hi: CallStack {getCallStack = [("?loc",SrcLoc {srcLocPackage = "main", srcLocModule = "Main", srcLocFile = "Hi.hs", srcLocStartLine = 17, srcLocStartCol = 35, srcLocEndLine = 17, srcLocEndCol = 39})]} }}} Uncommenting the type signature for `require` however results in more-or- less the expected callstack with 7.10.3, {{{#!hs $ ./Hi Hello world Hi: CallStack {getCallStack = [("?loc",SrcLoc {srcLocPackage = "main", srcLocModule = "Main", srcLocFile = "Hi.hs", srcLocStartLine = 18, srcLocStartCol = 35, srcLocEndLine = 18, srcLocEndCol = 39}),("require",SrcLoc {srcLocPackage = "main", srcLocModule = "Main", srcLocFile = "Hi.hs", srcLocStartLine = 14, srcLocStartCol = 14, srcLocEndLine = 14, srcLocEndCol = 21}),("fromEvents",SrcLoc {srcLocPackage = "main", srcLocModule = "Main", srcLocFile = "Hi.hs", srcLocStartLine = 24, srcLocStartCol = 5, srcLocEndLine = 24, srcLocEndCol = 15})]} }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12202> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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