Error code E0054

It is not allowed to cast to a bool.

Erroneous code example:

#![allow(unused)]
fn main() {
let x = 5;

// Not allowed, won't compile
let x_is_nonzero = x as bool;
}
ⓘ

If you are trying to cast a numeric type to a bool, you can compare it with zero instead:

#![allow(unused)]
fn main() {
let x = 5;

// Ok
let x_is_nonzero = x != 0;
}