Error code E0647

The start function was defined with a where clause.

Erroneous code example:

#![allow(unused)]
#![feature(start)]

fn main() {
#[start]
fn start(_: isize, _: *const *const u8) -> isize where (): Copy {
    //^ error: `#[start]` function is not allowed to have a where clause
    0
}
}