Matthew Pickering

I think this ticket is now about documentation. It would be good to provide instructions about invocations you need to push all the build dependencies to cachix. Something like ```...

Can you try [this link](https://environment.data.gov.uk/UserDownloads/interactive/e737cfc219704e03b4f4d6973e9cf857189432/NLP/National-LIDAR-Programme-Point-Cloud-2021-SK18ne.zip)? I am not sure if it will expire or is unique to me.

You are right that the IO is happening in performEvent, but performEventAsync doesn't work for me because of #404. One issue I see with performEvent is that in a push...

@cgibbard I have built an abstraction which should prevent these kinds of updates and which reports a different number of updates to the number of times `traceDynWith` fires. https://github.com/mpickering/ghcide/blob/reflex/src/Development/IDE/Core/Reflex/Early.hs

Perhaps would also be good to be able to easily instrument calls to `performEvent` as they could block for a reasonable amount of time.

I found myself wanting this feature today fwiw.

I think the `emojis` package might have the same issue.

I would be careful enabling `-O0` just for specific modules as it will affect how other modules are optimised due to [#20056](https://gitlab.haskell.org/ghc/ghc/-/issues/20056)

I am almost always setting per-project wrapper scripts which pass additional options to hls. This change would be quite inconvenient for me as well.

I don't see that there is a realistic prospect of "fixing" this within HLS because of the fundamental issue that `setCurrentDirectory` is not thread local, this makes it impossible to...