Suggest Upgrading Compiler for Gated Features

[George-lewis]

This PR addresses #117318

I have a few questions:

1. Do we want to specify the current version and release date of the compiler? I have added this in via environment variables, which I found in the code for the rustc cli where it handles the --version flag
   a. How can I handle the changing message in the tests?
2. Do we want to only show this message when the compiler is old?
   a. How can we determine when the compiler is old?

I'll wait until we figure out the message to bless the tests

[rustbot]

r? @compiler-errors

(rustbot has picked a reviewer for you, use r? to override)

[bjorn3]

Do we want to only show this message when the compiler is old?

It would introduce a source of non-determinism which as I understand it would make rustc tests fail if CI stalls just a bit too long or if someone tries to recompile an older nightly version and then run it's test suite for reproducibility reasons.

[George-lewis]

@bjorn3 That's a very good point about non-determinism. I think from a ui perspective it would be nice to show the message selectively, so perhaps if there's a way to make this deterministic for the tests, we can move forwards with it? Otherwise I'm ok with making this message static.

I'll wait for @compiler-errors to follow up

[Rajveer100]

@George-lewis
I have closed my PR since you have found the right place to debug, feel free to progress, meanwhile I will grind other ones.

[George-lewis]

Thank you, @Rajveer100, I appreciate that, and good luck to you

[compiler-errors]

r? nilstrieb

kinda too busy to continue to review this

[rustbot]

There are merge commits (commits with multiple parents) in your changes. We have a no merge policy so these commits will need to be removed for this pull request to be merged.

You can start a rebase with the following commands:

$ # rebase
$ git rebase -i master
$ # delete any merge commits in the editor that appears
$ git push --force-with-lease

The following commits are merge commits:

• 818f136

[George-lewis]

@rustbot label -S-waiting-on-author

[George-lewis]

@rustbot label -has-merge-commits

[rustbot]

Error: Label has-merge-commits can only be set by Rust team members

Please file an issue on GitHub at triagebot if there's a problem with this bot, or reach out on #t-infra on Zulip.

[bors]

☔ The latest upstream changes (presumably #119421) made this pull request unmergeable. Please resolve the merge conflicts.

[George-lewis]

@Nilstrieb Rebased and re-blessed the tests

[Noratrieb]

@bors r+ rollup=iffy

[bors]

📌 Commit d56cdd4 has been approved by Nilstrieb

It is now in the queue for this repository.

[bors]

⌛ Testing commit d56cdd4 with merge d78329b...

[bors]

☀️ Test successful - checks-actions
Approved by: Nilstrieb
Pushing d78329b to master...

[rust-timer]

Finished benchmarking commit (d78329b): comparison URL.

Overall result: ❌✅ regressions and improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.3%	[0.3%, 0.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.7%	[-0.7%, -0.7%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	3.4%	[3.4%, 3.4%]	1
Regressions ❌ (secondary)	4.1%	[3.0%, 5.3%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.3%	[-3.3%, -3.3%]	1
All ❌✅ (primary)	3.4%	[3.4%, 3.4%]	1

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.3%	[-2.3%, -2.3%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.3%	[-2.3%, -2.3%]	1

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 667.979s -> 668.17s (0.03%)
Artifact size: 308.20 MiB -> 308.19 MiB (-0.00%)

[Noratrieb]

🎉 thanks!

[George-lewis]

Great to finally get this in, thanks for your help @Nilstrieb 🎉