Arbitrary discriminants with `map = "compact"`

[ronnodas]

The Mapping Options section in the documentation for the derive macro says:

#[enumset(map = "compact")] maps each enum variant to an unspecified bit in the set. This allows the library to use less memory than it may otherwise and allows any discrminator [sic] values to be used without issue.

But I tried

#[derive(EnumSetType)]
#[enumset(map = "compact")]
#[repr(u8)]
pub enum Cased {
    CapitalA = b'A',
    ...
}

And got the error "Expression not supported by enumset.", even though this satisfies the Limitations section in the same docs. It seems negative discriminants aren't possible either (with a more cryptic error "expected Expr" when the #[enumset(map = "compact")] line is included), but at least this is called out in the limitations.

Is it possible to completely ignore the discriminants with the map = "compact" option? If not, the documentation should be updated.