Improve path segment joining #143922

nnethercote · 2025-07-14T09:51:44Z

Currently paths are joined with :: in many places, in a variety of ways. This PR unifies things.

r? @petrochenkov

nnethercote · 2025-07-14T10:51:38Z

@bors try @rust-timer queue

Improve path segment joining r? `@ghost`

bors · 2025-07-14T10:52:48Z

⌛ Trying commit f0a57ad with merge c0eee71...

bors · 2025-07-14T13:10:01Z

☀️ Try build successful - checks-actions
Build commit: c0eee71 (c0eee7172cfb3e789622d2a94af20e4345fcc338)

rust-timer · 2025-07-14T14:38:53Z

Finished benchmarking commit (c0eee71): comparison URL.

Overall result: ❌ regressions - no action needed

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.

@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
Regressions ❌ (secondary)	0.1%	[0.1%, 0.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary -1.6%)

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

	mean	range	count
Regressions ❌ (primary)	8.9%	[8.9%, 8.9%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-6.8%	[-7.0%, -6.6%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.6%	[-7.0%, 8.9%]	3

Cycles

Results (secondary -2.5%)

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

Binary size

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

Bootstrap: 465.735s -> 464.956s (-0.17%)
Artifact size: 374.64 MiB -> 374.59 MiB (-0.01%)

nnethercote · 2025-07-14T22:45:03Z

@jdonszelmann: you were talking about this a while back.

@camelid: this touches rustdoc in a lot of places, you might be interested.

nnethercote · 2025-07-14T22:45:56Z

Performance is neutral, which is what I was aiming for, given that this code is hot in some cases, especially doc builds.

@bors rollup=maybe

rustbot · 2025-07-14T22:46:06Z

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

samueltardieu

On the Clippy side, nice improvements by using interned symbols in more places, this is what we've been aiming at.

jdonszelmann · 2025-07-15T04:19:43Z

Lovely

compiler/rustc_resolve/src/diagnostics.rs

petrochenkov · 2025-07-15T13:54:02Z

r=me with #143922 (comment) addressed.
@rustbot author

rustbot · 2025-07-15T13:54:07Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

nnethercote · 2025-07-16T03:08:39Z

I addressed the comment.

@bors r=petrochenkov

bors · 2025-07-16T03:08:43Z

📌 Commit 6f427b3 has been approved by petrochenkov

It is now in the queue for this repository.

bors · 2025-07-16T03:08:43Z

🌲 The tree is currently closed for pull requests below priority 100. This pull request will be tested once the tree is reopened.

Improve path segment joining Currently paths are joined with `::` in many places, in a variety of ways. This PR unifies things. r? `@petrochenkov`

Improve path segment joining Currently paths are joined with `::` in many places, in a variety of ways. This PR unifies things. r? ``@petrochenkov``

Improve path segment joining Currently paths are joined with `::` in many places, in a variety of ways. This PR unifies things. r? ```@petrochenkov```

Rollup of 11 pull requests Successful merges: - #143595 (add `const_make_global`; err for `const_allocate` ptrs if didn't call) - #143678 (Added error for invalid char cast) - #143793 (Opaque type collection: Guard against endlessly recursing free alias types) - #143820 (Fixed a core crate compilation failure when enabling the `optimize_for_size` feature on some targets) - #143829 (Trim `BorrowedCursor` API) - #143856 (Linting public reexport of private dependencies) - #143891 (Port `#[coverage]` to the new attribute system) - #143914 (Reword mismatched-lifetime-syntaxes text based on feedback) - #143922 (Improve path segment joining) - #143926 (Remove deprecated fields in bootstrap) - #143975 (type_id_eq: check that the hash fully matches the type) r? `@ghost` `@rustbot` modify labels: rollup

fmease · 2025-07-16T21:56:30Z

#144038 (comment)
@bors r-

There are many places that join path segments with `::` to produce a string. A lot of these use `join("::")`. Many in rustdoc use `join_with_double_colon`, and a few use `.joined("..")`. One in Clippy uses `itertools::join`. A couple of them look for `kw::PathRoot` in the first segment, which can be important. This commit introduces `rustc_ast::join_path_{syms,ident}` to do the joining for everyone. `rustc_ast` is as good a location for these as any, being the earliest-running of the several crates with a `Path` type. Two functions are needed because `Ident` printing is more complex than simple `Symbol` printing. The commit also removes `join_with_double_colon`, and `estimate_item_path_byte_length` with it. There are still a handful of places that join strings with "::" that are unchanged. They are not that important: some of them are in tests, and some of them first split a path around "::" and then rejoin with "::". This fixes one test case where `{{root}}` shows up in an error message.

This one is a bit marginal, because the segments are a mix of symbols and strings.

nnethercote · 2025-07-16T22:38:14Z

I fixed the rustdoc error.

@bors r=petrochenkov

bors · 2025-07-16T22:38:16Z

📌 Commit 6414352 has been approved by petrochenkov

It is now in the queue for this repository.

Improve path segment joining Currently paths are joined with `::` in many places, in a variety of ways. This PR unifies things. r? `@petrochenkov`

Rollup of 15 pull requests Successful merges: - #142304 (tests: Add `RUST_BACKTRACE` and `-Cpanic` revisions to `panic-main.rs` test) - #143388 (Various refactors to the LTO handling code) - #143409 (Enable xgot feature for mips64 musl targets) - #143592 (UWP: link ntdll functions using raw-dylib) - #143595 (add `const_make_global`; err for `const_allocate` ptrs if didn't call) - #143678 (Added error for invalid char cast) - #143820 (Fixed a core crate compilation failure when enabling the `optimize_for_size` feature on some targets) - #143829 (Trim `BorrowedCursor` API) - #143846 (pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests) - #143851 (ci cleanup: rustdoc-gui-test now installs browser-ui-test) - #143856 (Linting public reexport of private dependencies) - #143895 (Dont collect assoc ty item bounds from trait where clause for host effect predicates) - #143922 (Improve path segment joining) - #143964 (Fix handling of SCRIPT_ARG in docker images) - #144016 (trait_sel: `MetaSized` always holds temporarily) r? `@ghost` `@rustbot` modify labels: rollup

Improve path segment joining Currently paths are joined with `::` in many places, in a variety of ways. This PR unifies things. r? ``@petrochenkov``

Rollup of 15 pull requests Successful merges: - #142304 (tests: Add `RUST_BACKTRACE` and `-Cpanic` revisions to `panic-main.rs` test) - #143388 (Various refactors to the LTO handling code) - #143409 (Enable xgot feature for mips64 musl targets) - #143592 (UWP: link ntdll functions using raw-dylib) - #143595 (add `const_make_global`; err for `const_allocate` ptrs if didn't call) - #143678 (Added error for invalid char cast) - #143820 (Fixed a core crate compilation failure when enabling the `optimize_for_size` feature on some targets) - #143829 (Trim `BorrowedCursor` API) - #143851 (ci cleanup: rustdoc-gui-test now installs browser-ui-test) - #143856 (Linting public reexport of private dependencies) - #143895 (Dont collect assoc ty item bounds from trait where clause for host effect predicates) - #143922 (Improve path segment joining) - #143964 (Fix handling of SCRIPT_ARG in docker images) - #144002 (Update poison.rs) - #144016 (trait_sel: `MetaSized` always holds temporarily) r? `@ghost` `@rustbot` modify labels: rollup

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 14, 2025

bors added a commit that referenced this pull request Jul 14, 2025

Auto merge of #143922 - nnethercote:join_path, r=<try>

c0eee71

Improve path segment joining r? `@ghost`

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 14, 2025

rustbot assigned petrochenkov Jul 14, 2025

nnethercote marked this pull request as ready for review July 14, 2025 22:46

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 14, 2025

samueltardieu approved these changes Jul 14, 2025

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petrochenkov reviewed Jul 15, 2025

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compiler/rustc_resolve/src/diagnostics.rs Outdated Show resolved Hide resolved

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 15, 2025

nnethercote force-pushed the join_path branch from f0a57ad to 6f427b3 Compare July 16, 2025 03:08

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 16, 2025

matthiaskrgr mentioned this pull request Jul 16, 2025

Rollup of 12 pull requests #144035

Closed

matthiaskrgr mentioned this pull request Jul 16, 2025

Rollup of 12 pull requests #144036

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matthiaskrgr mentioned this pull request Jul 16, 2025

Rollup of 11 pull requests #144038

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bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jul 16, 2025

nnethercote added 2 commits July 17, 2025 08:37

Use join_path_syms in one more place.

6414352

This one is a bit marginal, because the segments are a mix of symbols and strings.

nnethercote force-pushed the join_path branch from 6f427b3 to 6414352 Compare July 16, 2025 22:37

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 16, 2025

fmease mentioned this pull request Jul 16, 2025

Rollup of 15 pull requests #144041

Closed

fmease mentioned this pull request Jul 17, 2025

Rollup of 15 pull requests #144044

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Improve path segment joining #143922

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Improve path segment joining #143922

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rust-timer commented Jul 14, 2025

Overall result: ❌ regressions - no action needed

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