False positive in cast_sign_loss

[dtolnay]

I have some code like this in serde_yaml:

error: casting i64 to u64 may lose the sign of the value
   --> src/number.rs:172:37
    |
172 |                             if n <= i64::max_value() as u64 {
    |                                     ^^^^^^^^^^^^^^^^^^^^^^^

It would be nice to suppress cast_sign_loss in cases where Clippy can determine that the value is nonnegative, for example i64::MAX and i64::max_value().