Ah, so you installed the `cabal-install-3.0` package? Yes I attached your repo and then said apt install cabal-install and lo! cabal 3.0 appeared in /opt/cabal/bin I did this because the vanilla Ubuntu distro only had cabal 1.24. And I could not update by saying “cabal install cabal-install” because cabal 1.24 fell over with that “futex error”. In the meantime you can just keep using your current cabal 3.0 exe; does `cabal --version` currently have any noticeable startup latency for you on WSL? No, no noticeable startup latency. I’ll do the reinstall thing in a few hrs, after you’d done your update. Thanks! SImon From: Herbert Valerio Riedel <hvriedel@gmail.com> Sent: 04 April 2019 13:45 To: Simon Peyton Jones <simonpj@microsoft.com> Subject: Re: Help with cabal On Thu, Apr 4, 2019 at 2:25 PM Simon Peyton Jones <simonpj@microsoft.com<mailto:simonpj@microsoft.com>> wrote: But how do I "recompile your cabal 3.0 executable with the new GHC"? The cabal-3.0 I have is (I believe) installed by apt install cabal-install and so I suppose if I "upgrade", the new 'cabal' binary will WSL'd, no? Ah, so you installed the `cabal-install-3.0` package? If so, yes, it *will* be updated to the WSL version.... in about one hour... because it turns out I forgot to push the 3.0 packages to the WSL ppa... and I've just triggered a new build of cabal 3.0 packages which will take about one hour to show up there... :-) In the meantime you can just keep using your current cabal 3.0 exe; does `cabal --version` currently have any noticeable startup latency for you on WSL?