Check that the closure platform can reach the defect

What the check reads

The verify-stage error check examines KnownIssues with nonempty platforms declarations. With none declared, it reports skip. It distinguishes an unreachable-platform non-reproduction, a closure row with no platform, a reproduction outside the declared set and a malformed platform alternative. Tokens use axis:value notation, such as os:linux. The check evaluates recorded evidence; it does not discover all platform guards in source.

proof audit --check known_issue_closure_platform_bound

An illustrative case

Illustrative case: an issue concerns a Linux-only file-descriptor path, but its only non-reproduction came from macOS. The subject might simply have been skipped. The declaration platforms: [os:linux] lets the check reject that closure basis. Conversely, a successful reproduction outside the declaration challenges the declared scope and needs investigation.

Resolve the finding

1. Inspect the implementation guard and the platform constraints that actually make the path reachable.
2. Correct malformed or unsupported declarations rather than using them to exclude inconvenient evidence.
3. Run the reproducer on a relevant platform and retain its platform-stamped result. Reassess closure using all current observations.

What a clear result means

A reachable platform is necessary context, not proof that the test exercised the defect. This check prevents particular unsupported closure states; it does not establish a fix, cover all configurations or infer a complete support matrix. A known issue may remain open even after this check clears.

Continue with one real issue

Known issue platform coverage · Build matrix complete

Bring one finding, its requirement and the current evidence to scope a walkthrough of what your reviewer can establish and what still needs work.