// *** before: ***
// compile time arithmetic needed a named constant of its own
const BUF: usize = 16 * 4;
let buffer = [0u8; BUF];
// *** in version 1.79: ***
let buffer = [0u8; const { 16 * 4 }];
// in patterns as well
match len {
const { usize::MAX } => println!("the limit"),
_ => println!("an ordinary length"),
}