format: ignore println newline in foreign format hints by Dnreikronos · Pull Request #158222 · rust-lang/rust

Dnreikronos · 2026-06-21T17:56:57Z

println! adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing % look like % plus , so rustc printed a weird unsupported conversion specifier note.

imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

rustbot · 2026-06-21T17:57:01Z

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TaKO8Ki · 2026-06-22T19:07:48Z

@bors r+ rollup

rust-bors · 2026-06-22T19:07:52Z

📌 Commit 2a86b91 has been approved by TaKO8Ki

It is now in the queue for this repository.

🌲 The tree is currently closed for pull requests below priority 5. This pull request will be tested once the tree is reopened.

…_diagnostic, r=TaKO8Ki format: ignore println newline in foreign format hints fixes rust-lang#158216 `println!` adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing `%` look like `%` plus ` `, so rustc printed a weird unsupported conversion specifier note. imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

Rollup of 4 pull requests Successful merges: - #157960 (delegation: add support for infers in generics) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158222 (format: ignore println newline in foreign format hints) - #158252 (Use `cfg_select` in `std::os`)

…_diagnostic, r=TaKO8Ki format: ignore println newline in foreign format hints fixes rust-lang#158216 `println!` adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing `%` look like `%` plus ` `, so rustc printed a weird unsupported conversion specifier note. imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

Rollup of 6 pull requests Successful merges: - #157960 (delegation: add support for infers in generics) - #157983 (Lift the same-signature restriction for `extern "tail"`) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158222 (format: ignore println newline in foreign format hints) - #158252 (Use `cfg_select` in `std::os`)

…_diagnostic, r=TaKO8Ki format: ignore println newline in foreign format hints fixes rust-lang#158216 `println!` adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing `%` look like `%` plus ` `, so rustc printed a weird unsupported conversion specifier note. imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

Rollup of 6 pull requests Successful merges: - #157960 (delegation: add support for infers in generics) - #157983 (Lift the same-signature restriction for `extern "tail"`) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158222 (format: ignore println newline in foreign format hints) - #158274 (triagebot: Stop pinging myself)

…_diagnostic, r=TaKO8Ki format: ignore println newline in foreign format hints fixes rust-lang#158216 `println!` adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing `%` look like `%` plus ` `, so rustc printed a weird unsupported conversion specifier note. imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

Rollup of 6 pull requests Successful merges: - #157960 (delegation: add support for infers in generics) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158222 (format: ignore println newline in foreign format hints) - #158257 ( fix escaping placeholder check in next solver normalization folder) - #158274 (triagebot: Stop pinging myself)

…_diagnostic, r=TaKO8Ki format: ignore println newline in foreign format hints fixes rust-lang#158216 `println!` adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing `%` look like `%` plus ` `, so rustc printed a weird unsupported conversion specifier note. imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

Rollup of 8 pull requests Successful merges: - #157960 (delegation: add support for infers in generics) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158222 (format: ignore println newline in foreign format hints) - #158252 (Use `cfg_select` in `std::os`) - #158257 ( fix escaping placeholder check in next solver normalization folder) - #158274 (triagebot: Stop pinging myself) - #158282 (slice_split_once: bounds check optimization note)

…_diagnostic, r=TaKO8Ki format: ignore println newline in foreign format hints fixes rust-lang#158216 `println!` adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing `%` look like `%` plus ` `, so rustc printed a weird unsupported conversion specifier note. imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

…uwer Rollup of 16 pull requests Successful merges: - #156885 (Fix misattributed type inference error span for index expressions) - #157271 (simplify some `proc_macro` things) - #157883 (Remove strict invariant node_type on hir_type during ty privacy visit) - #157921 (trait solver: Resolve region vars in max universe) - #157960 (delegation: add support for infers in generics) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158279 (Follow goto and drop when linting unreachable code) - #157807 (don't ice on non-lifetime binders under `-Zassumptions-on-binders`) - #158020 (Update mingw-w64 C toolchain) - #158222 (format: ignore println newline in foreign format hints) - #158223 (Move target checking for #[lang] to the attribute parser) - #158252 (Use `cfg_select` in `std::os`) - #158257 ( fix escaping placeholder check in next solver normalization folder) - #158274 (triagebot: Stop pinging myself) - #158282 (slice_split_once: bounds check optimization note) Failed merges: - #158256 (Avoid parser panics bubbling out to proc macros)

…_diagnostic, r=TaKO8Ki format: ignore println newline in foreign format hints fixes rust-lang#158216 `println!` adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing `%` look like `%` plus ` `, so rustc printed a weird unsupported conversion specifier note. imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

…uwer Rollup of 23 pull requests Successful merges: - #158315 (`rust-analyzer` subtree update) - #155739 (Add temporary scope to assert_eq and assert_ne) - #156885 (Fix misattributed type inference error span for index expressions) - #157271 (simplify some `proc_macro` things) - #157883 (Remove strict invariant node_type on hir_type during ty privacy visit) - #157921 (trait solver: Resolve region vars in max universe) - #157960 (delegation: add support for infers in generics) - #157983 (Lift the same-signature restriction for `extern "tail"`) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158279 (Follow goto and drop when linting unreachable code) - #157527 (Move derive tests into their dedicated folder) - #157807 (don't ice on non-lifetime binders under `-Zassumptions-on-binders`) - #158020 (Update mingw-w64 C toolchain) - #158222 (format: ignore println newline in foreign format hints) - #158223 (Move target checking for #[lang] to the attribute parser) - #158252 (Use `cfg_select` in `std::os`) - #158257 ( fix escaping placeholder check in next solver normalization folder) - #158263 (Only load the feature list once in the entire resolver) - #158274 (triagebot: Stop pinging myself) - #158282 (slice_split_once: bounds check optimization note) - #158300 (Improve unknown crate_type diagnostic suggestions) - #158304 (mailmap: update mu001999) Failed merges: - #158256 (Avoid parser panics bubbling out to proc macros)

…_diagnostic, r=TaKO8Ki format: ignore println newline in foreign format hints fixes rust-lang#158216 `println!` adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing `%` look like `%` plus ` `, so rustc printed a weird unsupported conversion specifier note. imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

Rollup of 27 pull requests Successful merges: - #158315 (`rust-analyzer` subtree update) - #155739 (Add temporary scope to assert_eq and assert_ne) - #156885 (Fix misattributed type inference error span for index expressions) - #157271 (simplify some `proc_macro` things) - #157883 (Remove strict invariant node_type on hir_type during ty privacy visit) - #157921 (trait solver: Resolve region vars in max universe) - #157960 (delegation: add support for infers in generics) - #157983 (Lift the same-signature restriction for `extern "tail"`) - #158053 (Optimize network address parser) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158279 (Follow goto and drop when linting unreachable code) - #157527 (Move derive tests into their dedicated folder) - #157807 (don't ice on non-lifetime binders under `-Zassumptions-on-binders`) - #158020 (Update mingw-w64 C toolchain) - #158039 (c-variadic: test that we use equality up to free lifetimes) - #158222 (format: ignore println newline in foreign format hints) - #158223 (Move target checking for #[lang] to the attribute parser) - #158252 (Use `cfg_select` in `std::os`) - #158257 ( fix escaping placeholder check in next solver normalization folder) - #158263 (Only load the feature list once in the entire resolver) - #158267 (FromUtf8Error::into_utf8_lossy better example and suggest use) - #158274 (triagebot: Stop pinging myself) - #158282 (slice_split_once: bounds check optimization note) - #158300 (Improve unknown crate_type diagnostic suggestions) - #158304 (mailmap: update mu001999) - #158309 (Update `rustc-literal-escaper` version to `0.0.8`) Failed merges: - #158256 (Avoid parser panics bubbling out to proc macros)

…_diagnostic, r=TaKO8Ki format: ignore println newline in foreign format hints fixes rust-lang#158216 `println!` adds a newline before the unused-arg diagnostic checks for printf-style formats. that made a trailing `%` look like `%` plus ` `, so rustc printed a weird unsupported conversion specifier note. imo the least risky fix is to leave normal format parsing alone and only strip that synthetic newline for the foreign-format hint scan. idk if there is much more to do here, the ui tests cover the reported case plus the older trailing-percent baselines. lgtm to me, ltm this keeps the behavior narrow.

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 Jun 21, 2026

rustbot assigned TaKO8Ki Jun 21, 2026

Dnreikronos changed the title ~~format: Ignore println newline in foreign format hints~~ format: ignore println newline in foreign format hints Jun 21, 2026