Consider captured regions for opaque type region liveness.

[jackh726]

Fixes #153215

For opaques, when we're calculating liveness for opaques, we want to consider any captured lifetimes that can outlive the opaque type, which is more than just the outlives bounds.

r? lqd

[lqd]

Until I can look at this next week, @bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 97f0332 (97f0332b563f5fd8ae70b57a13a7b23b27db3012, parent: 0469a92a76c327df972cb6c1356934b7a0c6b86d)

[rust-timer]

Finished benchmarking commit (97f0332): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

This perf run didn't have relevant results for this metric.

Max RSS (memory usage)

Results (primary -2.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	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

Cycles

Results (secondary 2.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	4.1%	[3.3%, 4.9%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.1%	[-2.1%, -2.1%]	1
All ❌✅ (primary)	-	-	0

Binary size

Results (primary 0.2%, secondary 0.2%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.1%, 0.4%]	33
Regressions ❌ (secondary)	0.2%	[0.0%, 0.4%]	24
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[0.1%, 0.4%]	33

Bootstrap: 481.713s -> 483.106s (0.29%)
Artifact size: 390.96 MiB -> 390.99 MiB (0.01%)

[lqd]

I also started down this direction so some of this makes sense to me. We stopped because it felt fragile and test coverage was, and still is, weak. So with that caveat this generally feels fine to me, but again, I don't know enough about this area to say what problems there could be.

This direction felt less nice than what lcnr described in the t-types meeting where we described the issue, so I'll defer to them.

View changes since this review

[lqd]

I was also a bit worried, and we should expand test coverage here. I'm not confident enough in any of this to trust the two tests we have.

[lqd]

This is also unfortunate, combined with the fact that it's being called a quadratic number of times (thankfully the N should be small in most cases).