Enumerate lint expectations using AttrId

[cjgillot]

This PR implements the idea I outlined in #127884 (comment)

We can uniquely identify a lint expectation #[expect(lint0, lint1...)] using the AttrId and the index of the lint inside the attribute. This PR uses this property in check_expectations.

In addition, this PR stops stashing expected diagnostics to wait for the unstable -> stable LintExpectationId mapping: if the lint is emitted with an unstable attribute, it must have been emitted by an eval_always query (like inside the resolver), so won't be loaded from cache. Decoding an AttrId from the on-disk cache ICEs, so we have no risk of accidentally checking an expectation.

Fixes #127884

cc @xFrednet

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[cjgillot]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 94f8347 with merge f42cfbb...

[bors]

☀️ Try build successful - checks-actions
Build commit: f42cfbb (f42cfbbecfcb9306dd61e55c19101dfa87b5d3e8)

[rust-timer]

Finished benchmarking commit (f42cfbb): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

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

Instruction count

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

Max RSS (memory usage)

Results (secondary -2.5%)

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)	-	-	0
Improvements ✅ (secondary)	-2.5%	[-2.5%, -2.5%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 4.1%)

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)	4.1%	[4.1%, 4.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 756.217s -> 756.219s (0.00%)
Artifact size: 341.14 MiB -> 341.19 MiB (0.01%)

[fee1-dead]

LGTM, this is pretty much a clean up in my view.

[fee1-dead]

@bors r+

[bors]

📌 Commit 6dfc403 has been approved by fee1-dead

It is now in the queue for this repository.

[bors]

⌛ Testing commit 6dfc403 with merge 49bbdae...

[rust-log-analyzer]

The job x86_64-msvc-ext 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

[cjgillot]

@bors retry

[bors]

⌛ Testing commit 6dfc403 with merge 4c5fc2c...

[bors]

☀️ Test successful - checks-actions
Approved by: fee1-dead
Pushing 4c5fc2c to master...

[rust-timer]

Finished benchmarking commit (4c5fc2c): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

Results (secondary 2.1%)

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)	4.7%	[4.6%, 4.8%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.0%	[-3.0%, -3.0%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 21.1%)

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)	21.1%	[19.9%, 22.6%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 756.649s -> 755.32s (-0.18%)
Artifact size: 341.32 MiB -> 341.31 MiB (-0.00%)