Constant whose value would panic

Built from the repository at commit a8614dc.

Computing a constant's value follows the rules of run time. An operation that would panic at run time is an error at compile time, with the same message: "integer overflow" or "division by zero".

Why

A constant's value is computed before the program runs, so a panic in it would happen on every run. Only what run time would compute is checked: && and || skip their right side as at run time, and a comparison chain stops at its first false pair. Change the value so that it fits in its type, or does not divide by zero.

Broken

const MASK: u8 = 16 * 16

fn main() {
    print(MASK)
}

What sisu says

error[E0088]: integer overflow
 --> E0088.sisu:1:18
  |
1 | const MASK: u8 = 16 * 16
  |                  ^^^^^^^

sisu: 1 error
sisu: for more on a code, run `sisu explain <code>`: E0088

Fixed

const MASK: u8 = 16 * 15

fn main() {
    print(MASK)
}

Related

• E0040: integer literal too large for u8.