GHC Weekly News - 2015/01/27

[Austin Seipp]

Hi *,

It's time for the weekly GHC news. Over at GHC HQ, we discussed some
things this week including:

  - Austin took the time the past week to check `./validate
    --slow` failures, and is planning on filing bugs and fixes for the
    remaining failures soon. Afterwords, we'll immediately begin
    enabling `--slow` on Phabricator, so developers get their patches
    tested more thoroughly.

  - The 7.10 release looks like it will likely not have a 3rd Release
    Candidate, and will be released in late Feburary of 2015, as we
    originally expected.

  - The 7.10 branch currently has two showstopping bugs we plan on
    hitting before the final release. And we'd really like for users
    to test so we can catch more!

  - Austin Seipp will likely be gone for the coming week in a trip to
    New York City from the 28th to the 4th, meaning (much to the
    dismay of cheering crowds) you'd better catch him beforehand if
    you need him! (Alternatively Austin will be held back due to an
    intense snowstorm developing in NYC. So, we'll see!)

  - Austin is planning on helping the LLVM support in
    HEAD soon; after coordinating with Ben Gamari, we're hoping to
    ship GHC 7.12 with (at least) LLVM 3.6 as an officially supported
    backend, based on the documentation described in
    https://ghc.haskell.org/trac/ghc/wiki/ImprovedLLVMBackend - lots
    of thanks to Ben for working with upstream to file bugs and
    improve things!

And in other news, through chatter on the mailing list and Phabricator, we have:

  - Austin Seipp announced GHC 7.10.1 RC2:
https://www.haskell.org/pipermail/ghc-devs/2015-January/008140.html

  - Peter Trommler posted his first version of a native Linux/PowerPC
    64bit code generator! There's still a lot more work to do, but
    this is a significantly improved situation over the unregisterised
    C backend. Curious developers can see the patch at Phab:D629.

  - A long, ongoing thread started by Richard Eisenberg about the
    long-term plans for the vectorisation code have been posted. The
    worry is that the vectoriser as well as DPH have stagnated in
    development, which costs other developers any time they need to
    build GHC, make larger changes, or keep code clean. There have
    been a lot of varied proposals in the thread from removing the
    code to commenting it out, to keeping it. It's unclear what the
    future holds, but the discussion still rages on.
https://www.haskell.org/pipermail/ghc-devs/2015-January/007986.html

  - Karel Gardas is working on reviving the SPARC native code
    generator, but has hit a snag where double float load instructions
    were broken.
https://www.haskell.org/pipermail/ghc-devs/2015-January/008123.html

  - Alexander Vershilov made a proposal to the GHC team: can we remove
    the `transformers` dependency? It turns out to be a rather painful
    dependency for users of the GHC API and of packages depending on
    `transformers`, as you cannot link against any version other than
    the one GHC ships, causing pain. The alternative proposal involves
    splitting off the `transformers` dependency into a package of
    Orphan instances. The final decision isn't yet clear, nor is a
    winner in clear sight yet!
https://www.haskell.org/pipermail/ghc-devs/2015-January/008058.html

  - Konstantine Rybnikov has a simple question about GHC's error
    messages: can they say `Error:` before anything else, to be more
    consistent with warnings? It seems like a positive change - and it
    looks like Konstantine is on the job to fix it, too.
https://www.haskell.org/pipermail/ghc-devs/2015-January/008105.html

  - Simon Marlow has started a long thread about the fate of records
    in future GHC versions. Previously, Adam Gundry had worked on
    `OverloadedRecordFields`. And now Nikita Volkov has introduced his
    `records` library which sits in a slightly different spot in the
    design space. But now the question is - how do we proceed? Despite
    all prior historical precedent, it looks like there's finally some
    convergence on a reasonable design that can hit GHC in the future.
https://www.haskell.org/pipermail/ghc-devs/2015-January/008049.html

Closed tickets the past two weeks include: #9889, #9384, #8624, #9922,
#9878, #9999, #9957, #7298, #9836, #10008, #9856, #9975, #10013,
#9949, #9953, #9856, #9955, #9867, #10015, #9961, #5364, #9928, and
#10028.

-- 
Regards,

Austin Seipp, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com/