Recover missing `turbofish` for `lifetime` arguments in expression position by raushan728 · Pull Request #162749 · rust-lang/rust

raushan728 · 2026-09-14T05:56:25Z

Struct<'a> { .. } and f<'_>() were parsed as a < comparison whose RHS is a label, producing a cascade of unrelated errors. parse_path_segment now accepts < followed by a lifetime and >/, in expression paths, emits one "use ::<...>" suggestion, and parses the args normally.Since the recovery is inside the path parser, path.span and chained forms (::new(), .method(), ?) work without AST fix-ups or new Parser state; it is guarded by may_recover().

cc @estebank

rustbot · 2026-09-14T05:56:28Z

The parser was modified, potentially altering the grammar of (stable) Rust
which would be a breaking change.

cc @fmease

rustbot · 2026-09-14T05:56:31Z

r? @chenyukang

rustbot has assigned @chenyukang.
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estebank

I need to do a more in-depth review, as I have some mild concerns about increasing the size of the parser, but the results look reasonable so far. I'll look at this again later this week if the assigned reviewer doesn't manage to get the time before then.

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rustbot · 2026-09-14T15:48:38Z

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

raushan728 · 2026-09-15T14:37:12Z

@rustbot ready

chenyukang · 2026-09-19T12:30:54Z

r? @estebank since you already take review :)

nnethercote

This is looking much better! A couple of remaining nits.

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…uct expr

rustbot · 2026-10-13T12:43:39Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

nnethercote · 2026-10-13T19:44:31Z

Thanks for your patience on this one. I think the final version ended up much better than the first version :)

@bors r+

rust-bors · 2026-10-13T19:44:35Z

📌 Commit ebca075 has been approved by nnethercote

It is now in the queue for this repository.

@estebank

…rcote Recover missing `turbofish` for `lifetime` arguments in expression position Fixes rust-lang#162656. `Struct<'a> { .. }` and `f<'_>()` were parsed as a `<` comparison whose RHS is a label, producing a cascade of unrelated errors. `parse_path_segment` now accepts `<` followed by a lifetime and `>`/`,` in expression paths, emits one "use `::<...>`" suggestion, and parses the args normally.Since the recovery is inside the path parser, `path.span` and chained forms (`::new()`, `.method()`, `?`) work without AST fix-ups or new `Parser` state; it is guarded by `may_recover()`. cc @estebank

Rollup of 9 pull requests Successful merges: - #162749 (Recover missing `turbofish` for `lifetime` arguments in expression position) - #164170 (Prefer WriteConsoleW for stdout on Windows) - #164255 (test DSL eagerly handle false constraints) - #163230 (Document zero-sized allocations properly for `Box` and `Vec`) - #163940 (Parse move exprs as a bottom expr instead of a prefix expr) - #164219 (Windows FileExt trait doesn't need to handle ErrorKind::Interrupted; test improvements for same) - #164220 (Test the interaction between `--remap-path-prefix` and doctests) - #164266 (rustdoc: Improvements for `rustc_must_implement_one_of`) - #164278 (Output remapped paths in rustdoc JSON with the `documentation` scope)

@estebank

…rcote Recover missing `turbofish` for `lifetime` arguments in expression position Fixes rust-lang#162656. `Struct<'a> { .. }` and `f<'_>()` were parsed as a `<` comparison whose RHS is a label, producing a cascade of unrelated errors. `parse_path_segment` now accepts `<` followed by a lifetime and `>`/`,` in expression paths, emits one "use `::<...>`" suggestion, and parses the args normally.Since the recovery is inside the path parser, `path.span` and chained forms (`::new()`, `.method()`, `?`) work without AST fix-ups or new `Parser` state; it is guarded by `may_recover()`. cc @estebank

…uwer Rollup of 11 pull requests Successful merges: - #162749 (Recover missing `turbofish` for `lifetime` arguments in expression position) - #164170 (Prefer WriteConsoleW for stdout on Windows) - #164255 (test DSL eagerly handle false constraints) - #163230 (Document zero-sized allocations properly for `Box` and `Vec`) - #163940 (Parse move exprs as a bottom expr instead of a prefix expr) - #164219 (Windows FileExt trait doesn't need to handle ErrorKind::Interrupted; test improvements for same) - #164220 (Test the interaction between `--remap-path-prefix` and doctests) - #164266 (rustdoc: Improvements for `rustc_must_implement_one_of`) - #164272 (Add regression test for #155977) - #164287 (Add regression test for hang in overlap check with GAT alias) - #164301 (fix issue number for feature(unsized_const_params))

@estebank

…rcote Recover missing `turbofish` for `lifetime` arguments in expression position Fixes rust-lang#162656. `Struct<'a> { .. }` and `f<'_>()` were parsed as a `<` comparison whose RHS is a label, producing a cascade of unrelated errors. `parse_path_segment` now accepts `<` followed by a lifetime and `>`/`,` in expression paths, emits one "use `::<...>`" suggestion, and parses the args normally.Since the recovery is inside the path parser, `path.span` and chained forms (`::new()`, `.method()`, `?`) work without AST fix-ups or new `Parser` state; it is guarded by `may_recover()`. cc @estebank

@estebank

…rcote Recover missing `turbofish` for `lifetime` arguments in expression position Fixes rust-lang#162656. `Struct<'a> { .. }` and `f<'_>()` were parsed as a `<` comparison whose RHS is a label, producing a cascade of unrelated errors. `parse_path_segment` now accepts `<` followed by a lifetime and `>`/`,` in expression paths, emits one "use `::<...>`" suggestion, and parses the args normally.Since the recovery is inside the path parser, `path.span` and chained forms (`::new()`, `.method()`, `?`) work without AST fix-ups or new `Parser` state; it is guarded by `may_recover()`. cc @estebank

…uwer Rollup of 17 pull requests Successful merges: - #162749 (Recover missing `turbofish` for `lifetime` arguments in expression position) - #164165 (Add a new `rustc_show_spans` internal attribute) - #164170 (Prefer WriteConsoleW for stdout on Windows) - #164208 (Implement better resolution for delegation `Self` mapping field) - #164255 (test DSL eagerly handle false constraints) - #163230 (Document zero-sized allocations properly for `Box` and `Vec`) - #163442 (Fix fudging) - #163940 (Parse move exprs as a bottom expr instead of a prefix expr) - #164079 (document some quirks around directory symlinks on Windows) - #164178 (Fix `diagnostic::on_unknown` format placeholder for paths in expressions and type paths) - #164219 (Windows FileExt trait doesn't need to handle ErrorKind::Interrupted; test improvements for same) - #164266 (rustdoc: Improvements for `rustc_must_implement_one_of`) - #164272 (Add regression test for #155977) - #164287 (Add regression test for hang in overlap check with GAT alias) - #164292 (Remove the `span_use_eq_ctxt` lint) - #164301 (fix issue number for feature(unsized_const_params)) - #164309 (point at the opaque when its hidden type cannot be inferred)

@estebank

Rollup merge of #162749 - raushan728:issues/162656, r=nnethercote Recover missing `turbofish` for `lifetime` arguments in expression position Fixes #162656. `Struct<'a> { .. }` and `f<'_>()` were parsed as a `<` comparison whose RHS is a label, producing a cascade of unrelated errors. `parse_path_segment` now accepts `<` followed by a lifetime and `>`/`,` in expression paths, emits one "use `::<...>`" suggestion, and parses the args normally.Since the recovery is inside the path parser, `path.span` and chained forms (`::new()`, `.method()`, `?`) work without AST fix-ups or new `Parser` state; it is guarded by `may_recover()`. cc @estebank

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 Sep 14, 2026

rustbot assigned chenyukang Sep 14, 2026

estebank requested changes Sep 14, 2026

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Comment thread compiler/rustc_parse/src/parser/expr.rs Outdated

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 Sep 14, 2026

raushan728 force-pushed the issues/162656 branch from acf53ca to ce2a12a Compare September 15, 2026 14:20