Fix missing syntax context in lifetime hygiene debug output by aytey · Pull Request #151817 · rust-lang/rust

aytey · 2026-01-29T12:05:55Z

-Zunpretty=expanded,hygiene was not printing the syntax context for lifetimes. For example, two macro-generated lifetimes 'a with different hygiene would both print as /* 2538 */ instead of /* 2538#0 */ and /* 2538#1 */, making it impossible to distinguish them.

This was fixed by changing print_lifetime to call ann_post() with the full Ident, matching how regular identifiers are handled in print_ident.

Closes: #151797

rustbot · 2026-01-29T12:06:00Z

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`-Zunpretty=expanded,hygiene` was not printing the syntax context for lifetimes. For example, two macro-generated lifetimes `'a` with different hygiene would both print as `/* 2538 */` instead of `/* 2538#0 */` and `/* 2538#1 */`, making it impossible to distinguish them. This was fixed by changing `print_lifetime` to call `ann_post()` with the full `Ident`, matching how regular identifiers are handled in `print_ident`.

jdonszelmann · 2026-01-29T12:32:22Z

@bors r+ rollup

rust-bors · 2026-01-29T12:32:25Z

📌 Commit a333f6f has been approved by jdonszelmann

It is now in the queue for this repository.

…e, r=jdonszelmann Fix missing syntax context in lifetime hygiene debug output `-Zunpretty=expanded,hygiene` was not printing the syntax context for lifetimes. For example, two macro-generated lifetimes `'a` with different hygiene would both print as `/* 2538 */` instead of `/* 2538#0 */` and `/* 2538#1 */`, making it impossible to distinguish them. This was fixed by changing `print_lifetime` to call `ann_post()` with the full `Ident`, matching how regular identifiers are handled in `print_ident`. Closes: rust-lang#151797

…uwer Rollup of 3 pull requests Successful merges: - #151808 (Document a safety condition for `TypedArena::alloc_raw_slice`) - #151811 (Fix false positive in unused_parens caused by break) - #151817 (Fix missing syntax context in lifetime hygiene debug output)

…e, r=jdonszelmann Fix missing syntax context in lifetime hygiene debug output `-Zunpretty=expanded,hygiene` was not printing the syntax context for lifetimes. For example, two macro-generated lifetimes `'a` with different hygiene would both print as `/* 2538 */` instead of `/* 2538#0 */` and `/* 2538#1 */`, making it impossible to distinguish them. This was fixed by changing `print_lifetime` to call `ann_post()` with the full `Ident`, matching how regular identifiers are handled in `print_ident`. Closes: rust-lang#151797

…uwer Rollup of 4 pull requests Successful merges: - #151808 (Document a safety condition for `TypedArena::alloc_raw_slice`) - #151811 (Fix false positive in unused_parens caused by break) - #151817 (Fix missing syntax context in lifetime hygiene debug output) - #151836 (Fix flakyness issue with `tests/rustdoc-gui/globals.goml` test)

…e, r=jdonszelmann Fix missing syntax context in lifetime hygiene debug output `-Zunpretty=expanded,hygiene` was not printing the syntax context for lifetimes. For example, two macro-generated lifetimes `'a` with different hygiene would both print as `/* 2538 */` instead of `/* 2538#0 */` and `/* 2538#1 */`, making it impossible to distinguish them. This was fixed by changing `print_lifetime` to call `ann_post()` with the full `Ident`, matching how regular identifiers are handled in `print_ident`. Closes: rust-lang#151797

Rollup of 6 pull requests Successful merges: - #151777 ( Reduce generics use in the query system.) - #151808 (Document a safety condition for `TypedArena::alloc_raw_slice`) - #151811 (Fix false positive in unused_parens caused by break) - #151817 (Fix missing syntax context in lifetime hygiene debug output) - #151836 (Fix flakyness issue with `tests/rustdoc-gui/globals.goml` test) - #151844 (rustc-dev-guide subtree update)

Rollup of 5 pull requests Successful merges: - #151777 ( Reduce generics use in the query system.) - #151808 (Document a safety condition for `TypedArena::alloc_raw_slice`) - #151811 (Fix false positive in unused_parens caused by break) - #151817 (Fix missing syntax context in lifetime hygiene debug output) - #151844 (rustc-dev-guide subtree update)

Rollup merge of #151817 - aytey:fix_lifetime_unpretty_hygiene, r=jdonszelmann Fix missing syntax context in lifetime hygiene debug output `-Zunpretty=expanded,hygiene` was not printing the syntax context for lifetimes. For example, two macro-generated lifetimes `'a` with different hygiene would both print as `/* 2538 */` instead of `/* 2538#0 */` and `/* 2538#1 */`, making it impossible to distinguish them. This was fixed by changing `print_lifetime` to call `ann_post()` with the full `Ident`, matching how regular identifiers are handled in `print_ident`. Closes: #151797

Rollup of 5 pull requests Successful merges: - rust-lang/rust#151777 ( Reduce generics use in the query system.) - rust-lang/rust#151808 (Document a safety condition for `TypedArena::alloc_raw_slice`) - rust-lang/rust#151811 (Fix false positive in unused_parens caused by break) - rust-lang/rust#151817 (Fix missing syntax context in lifetime hygiene debug output) - rust-lang/rust#151844 (rustc-dev-guide subtree update)

RalfJung · 2026-09-10T16:35:40Z

The test you added here has very strange behavior. Just look at its git history:
https://github.com/rust-lang/rust/commits/676862daf62785e9aa0a614f91ce5683c66ccd25/tests/ui/hygiene/unpretty-debug-lifetimes.stdout
Every now and then we have to add or remove a newline.

I think it's because this normalization

// Don't break whenever Symbol numbering changes
//@ normalize-stdout: "\d+#" -> "0#"

doesn't normalize away newline differences.
So, the test still does sometimes break when symbol numbering changes... any way this could be avoided? It is causing confusion and CI failures.^^

aytey · 2026-09-10T18:58:48Z

The test you added here has very strange behavior. Just look at its git history: https://github.com/rust-lang/rust/commits/676862daf62785e9aa0a614f91ce5683c66ccd25/tests/ui/hygiene/unpretty-debug-lifetimes.stdout Every now and then we have to add or remove a newline.

I think it's because this normalization
// Don't break whenever Symbol numbering changes
//@ normalize-stdout: "\d+#" -> "0#"
doesn't normalize away newline differences. So, the test still does sometimes break when symbol numbering changes... any way this could be avoided? It is causing confusion and CI failures.^^

@RalfJung: I attempted to fix this here: #162608

rustbot assigned jdonszelmann Jan 29, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jan 29, 2026

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aytey force-pushed the fix_lifetime_unpretty_hygiene branch from 6bc4b5f to a333f6f Compare January 29, 2026 12:07

rust-bors Bot 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-review Status: Awaiting review from the assignee but also interested parties. labels Jan 29, 2026

JonathanBrouwer mentioned this pull request Jan 29, 2026

Rollup of 3 pull requests #151819

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JonathanBrouwer mentioned this pull request Jan 29, 2026

Rollup of 4 pull requests #151837

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Zalathar mentioned this pull request Jan 30, 2026

Rollup of 6 pull requests #151847

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Zalathar mentioned this pull request Jan 30, 2026

Rollup of 5 pull requests #151852

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rust-bors Bot merged commit dcc74dd into rust-lang:main Jan 30, 2026
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rustbot added this to the 1.95.0 milestone Jan 30, 2026

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Fix missing syntax context in lifetime hygiene debug output - #151817

Fix missing syntax context in lifetime hygiene debug output#151817
rust-bors[bot] merged 1 commit into
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aytey commented Jan 29, 2026 •

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