is_all() vs. from_bits_unchecked()

[niklasf]

unsafe from_bits_unchecked() allows creating instances with extra bits. The caller of the bitflags! macro can decide if this is allowed for their type. Let's assume it is for Example. I checked the provided methods for surprising interactions with extra bits, and found (only) this:

is_all() returns false when there are more than "all" flags. This does not match the documentation:

Returns true if all flags are currently set.

Should we update the documentation or the implementation?

---

use bitflags::bitflags;

bitflags! {
    struct Example: u32 {
        const A = 1;
    }
}

fn main() {
    unsafe {
        assert!(Example::from_bits_unchecked(1).is_all()); // true
        assert!(Example::from_bits_unchecked(3).is_all()); // false
    }
}

https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=cda2672387dd0ff4ba629b1317a9c57c