//@ run-pass #![allow(dead_code)] trait Range { const FIRST: u8; const LAST: u8; } struct OneDigit; impl Range for OneDigit { const FIRST: u8 = 0; const LAST: u8 = 9; } struct TwoDigits; impl Range for TwoDigits { const FIRST: u8 = 10; const LAST: u8 = 99; } struct ThreeDigits; impl Range for ThreeDigits { const FIRST: u8 = 100; const LAST: u8 = 255; } fn digits(x: u8) -> u32 { match x { OneDigit::FIRST..=OneDigit::LAST => 1, TwoDigits::FIRST..=TwoDigits::LAST => 2, ThreeDigits::FIRST..=ThreeDigits::LAST => 3, } } fn main() { assert_eq!(digits(100), 3); }