Concrete regions can show up in mir borrowck if the originated from there

[oli-obk]

We used to not encounter them here, because we took regions from typeck's opaque type resolution by renumbering them. We don't do that anymore. Instead mir borrock does all the logic, and it can handle concrete regions just fine, as long as it created them itself.

fixes#83190 which was introduced by #87287

r? @spastorino

[spastorino]

It would be nice to add a regression test for this particular thing. We could reduce the code from #83190, the bioyino-metric create, see #83190 (comment).

@rustbot ping cleanup-crew

To try to reduce that example and come up with a regression test.

Anyway, we're in a rush to merge this and backport to beta so ...

@bors r+ rollup=never

[bors]

📌 Commit 43738c6 has been approved by spastorino

[rustbot]

Hey Cleanup Crew ICE-breakers! This bug has been identified as a good
"Cleanup ICE-breaking candidate". In case it's useful, here are some
instructions for tackling these sorts of bugs. Maybe take a look?
Thanks! <3

cc @AminArria@camelid@chrissimpkins@contrun@DutchGhost@elshize@h-michael@HallerPatrick@hdhoang@hellow554@henryboisdequin@imtsuki@JamesPatrickGill@kanru@KarlK90@MAdrianMattocks@matheus-consoli@mental32@nmccarty@Noah-Kennedy@pard68@PeytonT@pierreN@Redblueflame@RobbieClarken@RobertoSnap@robjtede@SarthakSingh31@shekohex@sinato@smmalis37@steffahn@Stupremee@tamuhey@turboladen@woshilapin@yerke

[spastorino]

This fixes bioyino-metric and warp already works on nightly.
cc @Mark-Simulacrum

[jackh726]

@bors p=1
Want to make sure this gets in soon for backport

[bors]

⌛ Testing commit 43738c6 with merge a395610...

[bors]

☀️ Test successful - checks-actions
Approved by: spastorino
Pushing a395610 to master...

[pnkfelix]

During weekly performance triage, this was identified as causing a very small regression in instruction counts (up to 1.0% on incr-patched: add static arr item builds of coercions). As I noted in the triage report, this is a small regression to coercions and that may be noise. However, there are many others that are over 0.4% regression to instruction counts. The combination of those two factors led me to think that we may want to take a second look at the effects of this PR.

[oli-obk]

Since these examples compiled before this PR, and this PR solely removes a delay_span_bug, the only way perf can be affected is by llvm optimizing rustc differently. There can be no change in behaviour for existing code that successfully compiled

[Mark-Simulacrum]

The new significance algorithm essentially concurs that this was not after all a performance regression. If we do include very small changes, then there's a couple regressions, but those are pretty likely to be unrelated to this PR -- it looks like the majority of the new instructions come from llvm::PMTopLevelManager::findAnalysisPass and llvm::AAResultsWrapperPass::runOnFunction, which seem obviously irrelevant for this change.