Macro assert_lt 

macro_rules! assert_lt {
    ($left:expr, $right:expr $(,)?) => { ... };
    ($left:expr, $right:expr, $($arg:tt)+) => { ... };
}

Asserts that the left hand side expression is lesser than the right hand side expression

Examples

let a = 100; let b = 100;
#[cfg(should_panic)]
assert_lt!(a, b); // This would panic