Macro moore_svlog::assert_span

macro_rules! assert_span {
    ($cond:expr, $span:expr, $emitter:expr) => { ... };
    ($cond:expr, $span:expr, $emitter:expr,) => { ... };
    ($cond:expr, $span:expr, $emitter:expr, $($arg:tt)+) => { ... };
    (@IMPL $cond:expr, $span:expr, $emitter:expr, $($arg:tt)*) => { ... };
}

Assert that a condition holds, or emit a bug diagnostic and panic.