1 //! Checked arithmetic helpers. 2 3 /// `const fn`-friendly checked addition helper. 4 macro_rules! checked_add { 5 ($a:expr, $b:expr) => { 6 match $a.checked_add($b) { 7 Some(n) => n, 8 None => return Err(Error::Length), 9 } 10 }; 11 } 12