Younes Akhouayri 7dd6343fc1 rust: num: restrict bool conversion to unsigned Bounded ...

From<bool> turns true into 1. A signed Bounded with N = 1 can hold
only -1 and 0. The current implementation can therefore create a value
that breaks Bounded's invariant. Deref relies on that invariant and
calls unreachable_unchecked() when it is broken, so safe Rust can reach
undefined behavior.

The other primitive conversions require the source and destination to
have the same signedness. Treat bool as an unsigned one-bit value and
allow conversions between bool and Bounded only when the backing integer
type is unsigned.

Fixes: 01e345e82e ("rust: num: add Bounded integer wrapping type")
Closes: https://lore.kernel.org/rust-for-linux/[email protected]/
Cc: [email protected]
Suggested-by: Alexandre Courbot <[email protected]>
Assisted-by: Codex:gpt-5.6-sol
Signed-off-by: Younes Akhouayri <[email protected]>
Reviewed-by: Alexandre Courbot <[email protected]>
Link: https://patch.msgid.link/20260822-fix-rust-bounded-from-bool-submit-v4-1-aa780bfe7f30@younes.io
Signed-off-by: Miguel Ojeda <[email protected]>

2026-08-24 13:21:12 +02:00

..

bounded.rs

rust: num: restrict bool conversion to unsigned Bounded

2026-08-24 13:21:12 +02:00

casts.rs

rust: add functions and traits for lossless integer conversions

2026-08-13 13:41:28 +02:00