Remove Symbol from Named variant of BoundRegionKind/LateParamRegionKind

[compiler-errors]

The Symbol is redundant, since we already store a DefId in the region variant. Instead, load the name via item_name when needed (which is almost always on the diagnostic path).

This introduces a BoundRegionKind::NamedAnon which is used for giving anonymous bound regions names, but which should only be used during pretty printing and error reporting.

[compiler-errors]

@bors try @rust-timer queue

[bors]

⌛ Trying commit dba712a with merge 098a24f...

[bors]

☀️ Try build successful - checks-actions
Build commit: 098a24f (098a24f333aac968a2fcbf1e3d152550224ea44d)

[rust-timer]

Finished benchmarking commit (098a24f): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.1%, 0.3%]	4
Regressions ❌ (secondary)	0.3%	[0.2%, 0.4%]	12
Improvements ✅ (primary)	-0.2%	[-0.5%, -0.1%]	54
Improvements ✅ (secondary)	-0.3%	[-0.6%, -0.1%]	37
All ❌✅ (primary)	-0.2%	[-0.5%, 0.3%]	58

Max RSS (memory usage)

Results (primary -0.4%, secondary -0.4%)

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)	2.2%	[0.9%, 3.5%]	2
Regressions ❌ (secondary)	3.4%	[1.8%, 4.6%]	3
Improvements ✅ (primary)	-2.1%	[-2.6%, -1.5%]	3
Improvements ✅ (secondary)	-3.3%	[-3.9%, -2.1%]	4
All ❌✅ (primary)	-0.4%	[-2.6%, 3.5%]	5

Cycles

Results (primary 0.6%, secondary 1.4%)

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)	1.3%	[1.0%, 1.6%]	3
Regressions ❌ (secondary)	1.4%	[1.4%, 1.4%]	1
Improvements ✅ (primary)	-1.4%	[-1.4%, -1.4%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.6%	[-1.4%, 1.6%]	4

Binary size

Results (primary -0.1%, secondary -0.2%)

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)	-0.1%	[-0.3%, -0.0%]	118
Improvements ✅ (secondary)	-0.2%	[-0.8%, -0.0%]	33
All ❌✅ (primary)	-0.1%	[-0.3%, -0.0%]	118

Bootstrap: 780.203s -> 780.55s (0.04%)
Artifact size: 366.14 MiB -> 366.17 MiB (0.01%)

[bors]

☔ The latest upstream changes (presumably #140682) made this pull request unmergeable. Please resolve the merge conflicts.

[compiler-errors]

This is ready to review I think.

[rustbot]

r? @WaffleLapkin

rustbot has assigned @WaffleLapkin.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[rustbot]

HIR ty lowering was modified

cc @fmease

[compiler-errors]

@rustbot author