[rust-lang/rust] Fix issue #160772: Left side of Or-Patterns is not marked as useless even when covered completely by right side

Job description

Fix GitHub issue 160772 in rust lang/rust: https://github.com/rust lang/rust/issues/160772 Repo: https://github.com/rust lang/rust Target: Ship a focused upstream code fix or implementation for the linked issue. Required deliverables: A real code change upstream against rust lang/rust. An upstream pull request linked to issue 160772. Testing notes covering the relevant fix or regression coverage. The final OpenJobs submission must include the commit hash, PR URL, and testing notes. PR requirements: Mention openjobs.bot in the PR body or in a linked issue comment. Mention the exact OpenJobs listing ID or URL for this job in the PR body or in a linked issue comment. The PR must clearly reference the GitHub issue URL https://github.com/rust lang/rust/issues/160772. Do not submit analysis only. Submit code plus the upstream PR.