Remove Cased Unicode table

[Kmeakin]

Split off from #145219

Cased is a derived property - it is the union of the Lowercase property, the Uppercase property, and the Titlecase_Letter general categories. We already have lookup tables for Lowercase and Uppercase, and Titlecase_Letter is very small. So instead of duplicating a lookup table for Cased, just test each of those properties in turn.

This probably will be slower than the old approach, but it is not a public API: it is only used in string::to_lower when deciding when a Greek "sigma" should be mapped to ς or to σ. This is a very rare case, so should not be performance sensitive.

[rustbot]

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[rustbot]

library/core/src/unicode/unicode_data.rs is generated by the src/tools/unicode-table-generator tool.

If you want to modify unicode_data.rs, please modify the tool then regenerate the library source file via ./x run src/tools/unicode-table-generator instead of editing unicode_data.rs manually.

[Kobzol]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: abd6680 (abd6680cc4021a02ca80a20bb45c967f5cb9f056, parent: 033c0a4742794f5608b19eb78458726596f8ec18)

[rust-timer]

Finished benchmarking commit (abd6680): comparison URL.

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

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.2%]	1
Regressions ❌ (secondary)	0.4%	[0.4%, 0.4%]	1
Improvements ✅ (primary)	-0.3%	[-0.5%, -0.2%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.1%	[-0.5%, 0.2%]	3

Max RSS (memory usage)

Results (primary 0.4%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	4.3%	[4.3%, 4.3%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.6%	[-2.0%, -1.2%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.4%	[-2.0%, 4.3%]	3

Cycles

Results (secondary 2.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.0%	[2.0%, 2.0%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

Results (primary 0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.1%, 0.1%]	7
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.1%	[0.1%, 0.1%]	7

Bootstrap: 466.287s -> 464.864s (-0.31%)
Artifact size: 388.39 MiB -> 388.39 MiB (0.00%)

[bors]

☔ The latest upstream changes (presumably #146173) made this pull request unmergeable. Please resolve the merge conflicts.

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.