Landing: ac6b87632681

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Project / Subsystem

gcc / gccrs

Date

2026-06-28

Author

Lucas Ly Ba

Commit

ac6b8763268139027c363dfe7c0eb51eedc82b6c

Source

github

Perf win

Breaking

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All attributes

project: gcc
subsystem: gccrs
patch_id: —
commit_hash: ac6b8763268139027c363dfe7c0eb51eedc82b6c
source_type: github
headline: gccrs: add repr_c_enums_larger_than_int lint
tldr: gccrs warns about non-portable #[repr(C)] enums larger than C int types.
author: Lucas Ly Ba
outcome: committed
performance_win: false
breaking_change: false
series_id: —
series_parts: []
tags: • gccrs
• rust
• compiler
• lint
• ABI
discussion_id_link: —
bugzilla_pr: —
url: https://github.com/gcc-mirror/gcc/commit/ac6b8763268139027c363dfe7c0eb51eedc82b6c
date: 2026-06-28T00:00:00.000Z

A new lint in gccrs warns about Rust enums marked with #[repr(C)] whose discriminants exceed the size of C’s int or unsigned int. Such enums are non-portable because C standards (since C23) restrict enum sizes, and Rust’s isize interpretation for repr(C) discriminants might not match the C ABI. The discriminant is evaluated at compile time for this check.