Remove NtPat, NtMeta, and NtPath

[nnethercote]

Another part of #124141.

r? @petrochenkov

[nnethercote]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 96229ed with merge e6d1e42...

[nnethercote]

The recursion_limit overflow occurs in x doc compiler. Interestingly, it doesn't happen in #124141 which does the full nonterminal removal. I tried the individual commits:

ok    Remove `NtPat`.
bad   Remove `NtItem` and `NtStmt`.
bad   More denesting of invisibly-delimited groups.
bad   Remove `NtMeta`.
bad   Remove `NtPath`.
bad   Remove `NtExpr` and `NtLiteral`.
bad   Fix a problem with metavars and inner attributes.
ok    Remove `NtBlock`, `Nonterminal`, and `TokenKind::Interpolated`.
ok    Impl `Copy` for `Token` and `TokenKind`.
ok    Remove `TokenStream::flattened` and `InvisibleOrigin::FlattenToken`.

Somehow removing Nonterminal is enough to fix the problem. I was planning to merge these commits gradually, over multiple PRs, but maybe I'll just do NtPat in this PR and then the following seven commits in the next PR, because I don't know how else to work around this problem. (Increasing the recursion_limit to 256 looks like it would be necessary in lots of crates.)

[bors]

☀️ Try build successful - checks-actions
Build commit: e6d1e42 (e6d1e424e800c1e2505485e040f748a545171e70)

[rust-timer]

Finished benchmarking commit (e6d1e42): comparison URL.

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

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.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

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

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	2.2%	[0.2%, 3.1%]	14
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.7%	[-1.7%, -1.7%]	1
All ❌✅ (primary)	2.2%	[0.2%, 3.1%]	14

Max RSS (memory usage)

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

Cycles

Results (primary 2.6%, secondary -2.4%)

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)	2.6%	[1.6%, 3.1%]	12
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.4%	[-2.8%, -2.1%]	2
All ❌✅ (primary)	2.6%	[1.6%, 3.1%]	12

Binary size

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

Bootstrap: 770.178s -> 769.585s (-0.08%)
Artifact size: 359.64 MiB -> 359.66 MiB (0.01%)

[nnethercote]

I will restrict this to just the NtPat removal to avoid the doc problems. Let's try perf again.

@bors try @rust-timer queue

[bors]

⌛ Trying commit 372af98 with merge 2c86f0c...

[bors]

☀️ Try build successful - checks-actions
Build commit: 2c86f0c (2c86f0c5832c30bbbfcb2fc9fd9de4eefacf8303)

[nnethercote]

I want to cancel that perf run. Let's see if closing the PR will do that.

[nnethercote]

@bors try @rust-timer queue

[bors]

💔 Test failed - checks-actions

[rust-log-analyzer]

The job x86_64-apple-1 failed! Check out the build log: (web) (plain)

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

downloading https://ci-artifacts.rust-lang.org/rustc-builds/cb08599451226d780b2490f1aa9b414fe9e36657/rust-dev-nightly-x86_64-apple-darwin.tar.xz
extracting /Users/runner/work/rust/rust/build/cache/llvm-cb08599451226d780b2490f1aa9b414fe9e36657-false/rust-dev-nightly-x86_64-apple-darwin.tar.xz to /Users/runner/work/rust/rust/build/x86_64-apple-darwin/ci-llvm

thread 'main' panicked at src/bootstrap/src/core/download.rs:346:17:
member.unpack_in(dst) failed with failed to unpack `/Users/runner/work/rust/rust/build/x86_64-apple-darwin/ci-llvm/rust-dev-nightly-x86_64-apple-darwin/rust-dev/bin/llvm-split`
Build completed unsuccessfully in 0:00:45
  local time: Fri Feb 28 09:51:55 UTC 2025
  network time: Fri, 28 Feb 2025 09:51:55 GMT
##[error]Process completed with exit code 1.

[nnethercote]

@bors retry

[jieyouxu]

@bors p=5 (rollup scheduling; contains a fix for a P-critical issue)

[bors]

⌛ Testing commit 50076cd with merge aa3c2d7...

[bors]

☀️ Test successful - checks-actions
Approved by: petrochenkov
Pushing aa3c2d7 to master...

[rust-timer]

Finished benchmarking commit (aa3c2d7): comparison URL.

Overall result: ❌ regressions - please read the text below

Our benchmarks found a performance regression caused by this PR.
This might be an actual regression, but it can also be just noise.

Next Steps:

• If the regression was expected or you think it can be justified,
  please write a comment with sufficient written justification, and add
  @rustbot label: +perf-regression-triaged to it, to mark the regression as triaged.
• If you think that you know of a way to resolve the regression, try to create
  a new PR with a fix for the regression.
• If you do not understand the regression or you think that it is just noise,
  you can ask the @rust-lang/wg-compiler-performance working group for help (members of this group
  were already notified of this PR).

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	0.3%	[0.2%, 0.4%]	16
Regressions ❌ (secondary)	0.4%	[0.3%, 0.6%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.2%, 0.4%]	16

Max RSS (memory usage)

Results (primary -3.1%)

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)	-	-	0
Improvements ✅ (primary)	-3.1%	[-3.1%, -3.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-3.1%	[-3.1%, -3.1%]	1

Cycles

Results (secondary -0.0%)

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)	2.5%	[2.1%, 2.9%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-9.9%	[-9.9%, -9.9%]	1
All ❌✅ (primary)	-	-	0

Binary size

Results (primary 0.0%)

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)	0.0%	[0.0%, 0.0%]	8
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[0.0%, 0.0%]	8

Bootstrap: 771.31s -> 770.727s (-0.08%)
Artifact size: 361.99 MiB -> 361.98 MiB (-0.00%)

[nnethercote]

The perf regressions are expected and unavoidable, alas.

@rustbot label: +perf-regression-triaged