[MISRA C] Assess Clippy coverage for R.22.18

[PLeVasseur]

Task

Assess Clippy lint coverage for this mapping. If a suitable lint already exists, document it and link it from the related Safety Critical Rust guideline; otherwise, create the needed lint and then link that lint from the guideline.

Source mapping

• Standard: MISRA C
• Rule: R.22.18
• Title: TBD
• Mapping table: Table 1
• Applicability label: all-rust
• Source category: unspecified
• Existing Rust rule cell: empty
• Source file/object: src/appendices/standards-matrices/misra-c-2025-mapping.rst
• Source URL: none

Current table comment

No current comment provided.

Acceptance criteria

• Search rust-lang/rust-clippy for an existing lint covering the mapped Rust hazard.
• If a suitable lint exists, document it and link it from the related Safety Critical Rust guideline.
• If no suitable lint exists, create the needed lint, including examples and expected diagnostics.
• Link the Clippy tracking issue or PR if one is opened.
• Update or cross-link the related Safety Critical Rust guideline issue so the guideline can reference the lint once available.