Hi *, time for another piece of the GHC weekly news!
- Joachim Breitner has gotten the new GHC 7.8.4 package to tentatively build on ARM quite easily for Debian. Austin also took the liberty of merging all the needed patches; they'll be part of the 7.8.4 release https://www.haskell.org/pipermail/ghc-devs/2014-December/007608.html
- Greg Weber announced he's taken the time to set up a Docker image for GHC development - if you're on Linux, Greg's image should help you get up to speed with a GHC development environment in minutes! https://www.haskell.org/pipermail/ghc-devs/2014-December/007606.html
- Lennart Kolmodin has spent time working on autocompletion for GHC, and 7.10 will ship with bash completion scripts - which package maintainers and distributions can now ship for their users. Thank you Lennart! https://www.haskell.org/pipermail/ghc-devs/2014-December/007614.html
- Adam Gundry has a question about the new type checker plugin infrastructure; in particular - how do we deal with the serialization of type checker evidence that plugins may want to create or pass around on their own? Richard, Simon and Iavor weigh in. https://www.haskell.org/pipermail/ghc-devs/2014-December/007626.html
- For the past few days, Richard Eisenberg has been hunting a performance regression in the compiler. After profiling, discussion on IRC and elsewhere, Richard has finally made some headway, and discovered one of the 'hot spots' in his patch. Unfortunately the battle isn't quite over just yet, and the hunt for a few more % increase remains. https://www.haskell.org/pipermail/ghc-devs/2014-December/007645.html
- David Spies has hit a very strange situation with GHC 7.8.3 running out of memory. But it turned out this was a change in 7.8, in relation to how stacks were managed. Phew! https://www.haskell.org/pipermail/ghc-devs/2014-December/007646.html
- Austin made a final call for 7.8.4 bugfixes. He plans on making the final release this week, if nobody has any other major complaints. https://www.haskell.org/pipermail/ghc-devs/2014-December/007684.html
Finally, in a slight change, we'll also be covering some notes from this week's meeting between GHC HQ (Austin, Simon PJ, SimonM, Herbert and Mikolaj), including...
- The 7.10 RC1 looks like it's scheduled to occur this week still; all of our libraries and submodules are up-to-date, and we've taken the time to alert all of our maintainers about this. Thanks to Herbert for taking control of this!
- We'll soon be implementing a new 'push hook' for the
ghc.gitrepository: no more trailing whitespace. Since we've recently detabbed, and de-lhs-ified the tree, a knock-on effect was deleting trailing whitespace. Now that we've done a lot of this, we should take the time to enforce it - so they can't slip back in.
- This week, Austin managed to secure two sponsors for GHC/Haskell.org. We've been given a wonderful set of ARM buildbots (running in the cloud!) and a new, incredibly powerful POWER8 machine to use (with over 170 hardware threads available, for scalability testing). Hooray for our friends at Online.net and RunAbove.com for helping us out!
Closed tickets this week include: #9871, #9808, #9870, #9605, #9874, #9872, #9090, #9404, #8240, #9567, #9566, #9583, #9117, #9882, #9884, #9372, #7942, #8951, #9817, #9620, #9336, #9523, #9552, #8988, #9390, #9415, #9371, #7143, #9563, #8778, #4428, #4896, #9393, #9169, #7015, #8943, #8621, #9132, #9857, #8024, #9831, and #9888.
Once more, it's time for some news about GHC! This week's regularly scheduled programming (get it?) has brought you...
- As of last week, GHC officially has no more
.lhsfiles in its source repository; instead, all files have been converted to
.hsand are now much more consistent with each other: https://www.haskell.org/pipermail/ghc-devs/2014-December/007552.html
- Joachim Breitner has reported that the
linker_unloadtest in GHC has been failing, but it's been surprisingly hard to reproduce reliably on our build machines! https://www.haskell.org/pipermail/ghc-devs/2014-December/007528.html
- Moritz Angermann posted a proposal about the "Out of Process Template Haskell" project, started by the GHCJS developers. In short, they want to work out how to get Template Haskell working in a stage2 GHC for things like iOS or Browser devices: https://www.haskell.org/pipermail/ghc-devs/2014-December/007555.html
- Lennart Augustsson has an inquiry about his program: why is it running out of memory? But the stranger thing: why does it only run out if heap profiling is not enabled? Nobody has quite figured out, but if you're a guru, it may be a good chance to help out: https://www.haskell.org/pipermail/ghc-devs/2014-December/007582.html
- Yuras Shumovich tracked down some nasty bugs in the typechecker's linter, causing several programs to fail to work when compiled by GHC. A quick diagnosis, but no fix has been merged quite yet: https://www.haskell.org/pipermail/ghc-devs/2014-December/007580.html
- Richard Eisenberg wants feedback on a what he thinks is a design wart in the use of
-XStandaloneDeriving, and he's not only proposed a solution, but wants to know what people think; typechecking fans are surely puzzling away already: https://www.haskell.org/pipermail/ghc-devs/2014-December/007589.html
- David Spies has run into an interesting situation: why does -O make his program slower instead of faster? Well, nobody has quite figured out why yet, but it's an interesting question - maybe on a lazy monday developer can help figure out: https://www.haskell.org/pipermail/ghc-devs/2014-December/thread.html
- Richard E. has another thread on the list, this time about development work flows: what do we do about painful merges? https://www.haskell.org/pipermail/ghc-devs/2014-December/007586.html
Closed tickets this week include: #9850, #9005, #9828, #9833, #9582, #8935, #9186, #9480, #9497, #7908, #4347, #3977, #3859, #3844, #3814, #3771, #3739, #2182, #9812, #4921, #7947, #9240, #5401, #3625, #3517, #9444, #9142, #3447, #8894, #3065, #3191, #2697, #2836, #5443, #7736, #2489, #2456, #2204, #9777, #9859, #9869, #9808
It's that time again for some good ol' fashion GHC news, this time just after the holidays. Some of the things happening in the past week include:
- Partial Type Signatures has been merged into HEAD. Many thanks to Thomas Winant, who worked on this feature for several months!
- As mentioned last week, GHC 7.10 will no longer ship
- Neil Mitchell asked a very good question on
ghc-devs: what's the process for getting your library synced for the GHC 7.10 release? As the maintainer of
filepathhe'd like to know, and Herbert responded quickly: https://www.haskell.org/pipermail/ghc-devs/2014-November/007394.html
- Yuras Shumovich has more questions about exception handling, primarily: why is
waitQSem? Simon Marlow responds: https://www.haskell.org/pipermail/ghc-devs/2014-November/007394.html
- Carter Schonwald reports that GHC is having problems building on OS X with XCode 6, but Kazu Yamamoto replied he had no problem - perhaps some OS X wizards can help figure out the discrepancy: https://www.haskell.org/pipermail/ghc-devs/2014-November/007394.html
- Austin Seipp announced GHC 7.8.4 Release Candidate 1, with about a dozen bugfixes for major features: https://www.haskell.org/pipermail/ghc-devs/2014-November/007438.html
- Gergo Erdi asked about backporting pattern synonym type signatures to 7.8.4. The conclusion? Probably won't happen - it's a bit too late! https://www.haskell.org/pipermail/ghc-devs/2014-November/007440.html
- Carter Schonwald had some questions about the let-app invariant and primop code, which he was puzzling about to help with some code generation work. There are also some nice discussions of caches and prefetching in pure programs later on, too: https://www.haskell.org/pipermail/ghc-devs/2014-November/007440.html & https://www.haskell.org/pipermail/ghc-devs/2014-November/007410.html
- Ben Gamari talked about the current status of GHC and LLVM, GHC on ARM, and the future of our LLVM support on both the mailing lists, and his blog. A good read overall for those interested in the war-stories of GHC-on-ARM: https://www.haskell.org/pipermail/ghc-devs/2014-November/007469.html
Closed tickets this week include: #9827, #7475, #9826, #7460, #7643, #8044, #8031, #7072, #3654, #7033, #9834, #6098, #6022, #5859, #5763, #9838, #9830, #7243, #9736, #9574, #5158, #9844, #9281, #9818, #4429, #8815, #2182, #4290, #9005, #9828, #9833, #9582, and #9850.
Another huge thanks to Thomas Miedema who closed an extraordinary amount of tickets for us - the above list is still not even complete, and he's made a huge impact on the amount of open tickets in the past month or so.