rust-disciplinelisted

# Rust Discipline ## Purpose Catch high-signal Rust mistakes before they land. Apply these rules to public (`pub`) and crate-public (`pub(crate)`) function signatures, struct definitions, and trait bounds. Use it when you author or change a signature, when you review a diff, and when you tighten code before a merge. Apply every rule to every changed signature, not only to the first one. Each rule carries a severity: | Severity | Meaning | |----------|---------| | CRITICAL | Blocks the merge. The defect is silent, or it breaks downstream code. | | WARNING | Fix it, or write a one-line justification in the diff. | Deep material lives in the reference files. Open one when the diff matches its row. | Reference | Read it when the diff adds | |-----------|----------------------------| | [`references/type-and-trait-traps.md`](references/type-and-trait-traps.md) | a trait impl, a `Drop` impl, a newtype, or a lifetime parameter | | [`references/trait-resolution.md`](references/trait-resolution.md) | a `Deref` impl, an extension trait, a `downcast_ref` chain, a pointer-forwarding impl, a blanket impl, or a second conversion impl on one type pair | | [`references/data-shape-traps.md`](references/data-shape-traps.md) | a hash key, a text reversal, or a large array | | [`references/argument-shapes.md`](references/argument-shapes.md) | a parameter or return shape on a `pub` signature | | [`references/drop-and-raii.md`](references/drop-and-raii.md) | a `Drop` impl, a guard type, or