Get rid of 'tcx lifetime on ConstVid, EffectVid

[compiler-errors]

These are simply newtyped numbers, so don't really have a reason (per se) to have a lifetime -- TyVid and RegionVid do not, for example.

The only consequence of this is that we need to use a new key type for UnifyKey that mentions 'tcx. This is already done for RegionVid, with RegionVidKey<'tcx>, but this UnifyKey trait implementation may have been the original reason to give ConstVid a lifetime. See the changes to compiler/rustc_middle/src/infer/unify_key.rs specifically.

I consider the code cleaner this way, though -- we removed quite a few unnecessary 'tcx in the process. This also makes it easier to uplift these two ids to rustc_type_ir, which I plan on doing in a follow-up PR.

r? @BoxyUwU

[BoxyUwU]

@bors r+ rollup=never

[bors]

📌 Commit a986ab4 has been approved by BoxyUwU

It is now in the queue for this repository.

[bors]

⌛ Testing commit a986ab4 with merge 2e4e2a8...

[bors]

☀️ Test successful - checks-actions
Approved by: BoxyUwU
Pushing 2e4e2a8 to master...

[rust-timer]

Finished benchmarking commit (2e4e2a8): comparison URL.

Overall result: ✅ 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
Improvements ✅ (primary)	-3.9%	[-3.9%, -3.9%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-3.9%	[-3.9%, -3.9%]	1

Max RSS (memory usage)

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

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)	-3.7%	[-3.7%, -3.7%]	1
Improvements ✅ (secondary)	-4.8%	[-6.7%, -2.7%]	4
All ❌✅ (primary)	-3.7%	[-3.7%, -3.7%]	1

Binary size

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

Bootstrap: missing data
Artifact size: 304.40 MiB -> 304.40 MiB (-0.00%)