Error code E0589

The value of N that was specified for repr(align(N)) was not a power of two, or was greater than 2^29.

Erroneous code example:

#![allow(unused)]
fn main() {
#[repr(align(15))] // error: invalid `repr(align)` attribute: not a power of two
enum Foo {
    Bar(u64),
}
}