Refactor SyntaxContext::ctxt logic.

[cjgillot]

I'm still trying to make a test from the issue.

cc @deepink-mas does this solve the issue?

Fixes #110230

[rustbot]

r? @b-naber

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[b-naber]

The change looks good to me.

I tried to check whether this fixes the example in the issue, but I cannot even reproduce the issue.

@cjgillot Do you want this to be merged now or wait until you come up with a test?

[cjgillot]

The issue is very hard to reproduce, as it relies on the exact number of characters. I think merging without a test is fine: the old code was wrong.

[b-naber]

@bors r+ rollup

[bors]

📌 Commit 99962a8 has been approved by b-naber

It is now in the queue for this repository.

[bors]

⌛ Testing commit 99962a8 with merge f12a7fa...

[bors]

☀️ Test successful - checks-actions
Approved by: b-naber
Pushing f12a7fa to master...

[rust-timer]

Finished benchmarking commit (f12a7fa): comparison URL.

Overall result: ❌ regressions - 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)	0.4%	[0.4%, 0.5%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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)	0.8%	[0.8%, 0.8%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.3%	[-1.3%, -1.3%]	1
All ❌✅ (primary)	0.8%	[0.8%, 0.8%]	1

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)	11.7%	[7.5%, 16.6%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.7%	[-1.7%, -1.7%]	1
All ❌✅ (primary)	-	-	0