Unify defined_lib_features and lib_features queries

[compiler-errors]

Extracts part of #115623 (comment)

I went with also introducing a FeatureStability enum, instead of using Some(span) to mean stable and None to mean unstable.

r? @cjgillot

[compiler-errors]

committed this and then got in bed, will fix tomorrow

@rustbot author

[bjorn3]

Maybe it could directly be serialized into the crate metadata in this format?

[compiler-errors]

Seems less beneficial to store a bunch of DUMMY_SP in the metadata. Code is simpler now that cjgillot's comment above is applied.

[bors]

☔ The latest upstream changes (presumably #116688) made this pull request unmergeable. Please resolve the merge conflicts.

[compiler-errors]

@rustbot ready

[cjgillot]

r=me with a few nits

[compiler-errors]

@bors r=cjgillot

[bors]

📌 Commit 2d187d5 has been approved by cjgillot

It is now in the queue for this repository.

[bors]

⌛ Testing commit 2d187d5 with merge 8534923...

[bors]

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing 8534923 to master...

[rust-timer]

Finished benchmarking commit (8534923): 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)	2.5%	[2.5%, 2.5%]	1
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
Regressions ❌ (secondary)	4.0%	[4.0%, 4.0%]	1
Improvements ✅ (primary)	-1.1%	[-1.1%, -1.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.1%	[-1.1%, -1.1%]	1

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: 677.57s -> 675.862s (-0.25%)
Artifact size: 313.75 MiB -> 313.73 MiB (-0.01%)