enable test_join test in Miri

[RalfJung]

Miri for quite a while now has a hack to support self-referential generators: non-Unique mutable references are exempt from aliasing conditions. So we can run this test now. (It passes.)

Also extend a comment in a Vec test, while I am at it.

[rustbot]

r? @m-ou-se

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[JohnTitor]

Neat! @bors r+ r? @JohnTitor

[bors]

📌 Commit e1338cc has been approved by JohnTitor

It is now in the queue for this repository.

[bors]

⌛ Testing commit e1338cc with merge d9c13cd...

[bors]

☀️ Test successful - checks-actions
Approved by: JohnTitor
Pushing d9c13cd to master...

[bors]

☀️ Test successful - checks-actions
Approved by: JohnTitor
Pushing d9c13cd to master...

[rust-timer]

Finished benchmarking commit (d9c13cd): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

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)	-	-	0
Regressions ❌ (secondary)	2.9%	[2.9%, 2.9%]	1
Improvements ✅ (primary)	-4.0%	[-4.0%, -4.0%]	1
Improvements ✅ (secondary)	-2.4%	[-2.4%, -2.4%]	1
All ❌✅ (primary)	-4.0%	[-4.0%, -4.0%]	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)	3.6%	[3.6%, 3.6%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 658.838s -> 658.504s (-0.05%)