Thanks for bringing this up. I've merged the PR and uploaded Happy 1.19.10 to Hackage. Can someone else look at steps 3-5?
Cheers Simon On Wed, 8 May 2019 at 09:51, Vladislav Zavialov <[email protected]> wrote: > Hello ghc-devs, > > This February I did some changes to the parser that require higher rank > types support in ‘happy’. Unfortunately, as I discovered, happy’s --coerce > option is severely broken in the presence of higher rank types, so I had to > disable it. My benchmarks have shown a 10% slowdown from disabling --coerce > (https://gist.github.com/int-index/38af0c5dd801088dc1de59eca4e55df4). > > Alongside my changes I submitted a pull request to happy which fixes the > issue (https://github.com/simonmar/happy/pull/134), in the hope that it > would get merged, released, and I could re-enable --coerce in GHC ‘happy' > configuration. > > Unfortunately, my patch has been ignored to this day (for 3 months now), > and the performance regression reached 8.8-alpha. We need to act swiftly if > we want to avoid a performance regression in the actual release. Here’s > what needs to be done: > > 1. Merge https://github.com/simonmar/happy/pull/134 > 2. Release a new ‘happy’ > 3. (Optional) Specify in GHC’s build system that it builds only with the > latest 'happy' release > 4. Restore the --coerce option in GHC’s build system ‘happy’ configuration > 5. Backport it to the ghc-8.8 branch > > I have no access to do 1 & 2, I believe Simon Marlow does. I’d appreciate > if someone took care of 3, currently the build system does not install > ‘happy’ and assumes a system-wide installation without checking its > version. This means that users of all but the newly released version will > encounter obscure error messages. We need a version check. Then I will do > 4, as planned, and create a merge request for 5. > > All the best, > - Vladislav > _______________________________________________ > ghc-devs mailing list > [email protected] > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs >
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