Remove lub_empty from lexical region resolve

[spastorino]

As of my understanding this method made sense when we had ReEmpty.
Removed lub_empty and made the calling site code equivalent.

r? @lcnr @compiler-errors

[lcnr]

r=me after nit

afaict this code uses VarValue::Empty for fully unconstrained regions? Does it make sense to change its name to VarValue::Unconstrained

[spastorino]

@bors r=lcnr

r=me after nit

afaict this code uses VarValue::Empty for fully unconstrained regions? Does it make sense to change its name to VarValue::Unconstrained

👍, going to address this in a follow-up.

[bors]

📌 Commit b92840a has been approved by lcnr

It is now in the queue for this repository.

[bors]

⌛ Testing commit b92840a with merge 56e35c600b91c901706dc2b7a899e3e05eb88fc9...

[rust-log-analyzer]

The job armhf-gnu failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

[bors]

💔 Test failed - checks-actions

[spastorino]

Failing test failed with Connection reset by peer (os error 104), completely unrelated to this PR.

@bors retry

[bors]

⌛ Testing commit b92840a with merge 69e97df...

[bors]

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing 69e97df to master...

[rust-timer]

Finished benchmarking commit (69e97df): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Warning ⚠: The following benchmark(s) failed to build:

• rustc

cc @rust-lang/wg-compiler-performance

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)	1.2%	[1.2%, 1.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

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

Binary size

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

Bootstrap: missing data
Artifact size: 316.03 MiB -> 316.12 MiB (0.03%)

[Kobzol]

This PR apparently broke the rustc bootstrap benchmark.

[lqd]

It looks maybe transient? It was a checksum error

downloading https://static.rust-lang.org/dist/2023-08-22/rustc-nightly-x86_64-unknown-linux-gnu.tar.xz
invalid checksum: 
found:    7fbe014d55dc04266d8d0b4c7d544e4450a036d5b2f302b1fd2fa96495f2774e
expected: bdd970bee618fc6299249ec162ab7e38efdf52c77cd431ad9268f327a6f0905d

and it's not shown on the status page: the PR after this one successfully gathered bootstrap timings, as did the others that followed.

Others have encountered similar checksum errors during bootstrap: in #115275 where the verification has the expected checksum that is in the error above:

invalid checksum: 
found:    bd65ba88eff2a212f87030efe2098bdd2ffdcc770fe3b52e0731c830739dd48a
expected: 95b36f95b1e697922b6dceeaceb74da030d436340cb4ba764101c218c3bcb786