Switch to new Rust edition

[Furisto]

Now that a new rust edition has been released we should switch to the new edition, provided we do not see an increase in compile times.

[chenyukang]

I have a project which has the increase on link, it's much slower in generating final binary. 😂

The link stage cost 4 minutes to finish, but for 1.54.0, I only need 1 minute to compile the whole project from scratch.

[yihuaf]

@chenyukang The number you mentioned is not Youki right? Can we have some basic benchmark number for the difference in compilation time? Can you also post the CPU number and memory of the machine you use?

[chenyukang]

@chenyukang The number you mentioned is not Youki right? Can we have some basic benchmark number for the difference in compilation time? Can you also post the CPU number and memory of the machine you use?

It's not number of Youki, some others are reporting the same issue.
rust-lang/rust#90180

[yihuaf]

Looks like they recognize now that it is a regression in 1.56. We can either:

1. hold off the upgrade for 2 weeks or 1 month and check again. Or
2. upgrade now if the build performance is not that bad and just wait for the fix.

Either way is fine with me as long as for option (2) the compilation time doesn't become really terrible (I was hoping @chenyukang can provide us with some number for Youki). If we are not in a hurry, we can choose option (1).

[utam0k]

Since there is no reason to rush the upgrade to 1.56, I prefer option 1.

[chenyukang]

Looks like they recognize now that it is a regression in 1.56. We can either:

1. hold off the upgrade for 2 weeks or 1 month and check again. Or
2. upgrade now if the build performance is not that bad and just wait for the fix.

Either way is fine with me as long as for option (2) the compilation time doesn't become really terrible (I was hoping @chenyukang can provide us with some number for Youki). If we are not in a hurry, we can choose option (1).

I didn't experience link regression in Youki.
Prefer to option 1. I

[jcdyer]

Note, the 1.56 performance regression in rust-lang/rust#90180 (which I reported) is not a link time issue. perf reports all the time spent in librustcdriver, which is the actual compilation.

[tsturzl]

I'd also opt for option 1, as I don't really think there is much to be immediately gained.

[yihuaf]

Great. Let's revisit this issue in a month or so.

[YJDoc2]

Hey, now that #405 is merged, can we close this issue?