How to speed up the Rust compiler some more in 2020
> Each Tuesday I have been looking at the performance results of all the PRs merged in the past weekI really appreciate the work described here, but it seems to me that the performance tests are in exactly the wrong place. The correct time to benchmark a PR is before it is merged; not after. It's the same for any other kind of test; your tests should pass before you merge, not after.Sure, there will be exceptions where a performance regression is appropriate. But that should be known and agreed on before merging it.I don't see a strong reason that the performance tests have to be done afterwards. I presume that it's okay to have a delay between creating the pull request and its merge, since humans will typically want to be able to review it!