[MISRA C] Write Safety Critical Rust guideline for R.19.2

[PLeVasseur]

Task

Write a Safety Critical Rust coding guideline covering this source rule.

Source mapping

• Standard: MISRA C
• Rule: R.19.2
• Title: TBD
• Mapping table: Table 1
• Applicability label: all-rust
• Source category: Required
• Existing Rust rule cell: :need:gui_0cuTYG8RVYjg
• Source file/object: src/appendices/standards-matrices/misra-c-2025-mapping.rst
• Source URL: none

Current table comment

No current comment provided.

Acceptance criteria

• Use the coding guideline issue form as the field checklist: https://github.com/rustfoundation/safety-critical-rust-coding-guidelines/issues/new?template=CODING-GUIDELINE.yml
• Decide the Rust guideline title, chapter, category, decidability, scope, FLS linkage, examples, rationale, and bibliography.
• Reuse or cite any existing Safety Critical Rust guideline if this mapping is already covered.
• Update the source mapping table with the resulting guideline reference.
• If this rule should be merged with another source rule, document the merge rationale and update both mapping rows.