Macro const_assert

macro_rules! const_assert {
    ($cond:expr $(,)?) => { ... };
    ($cond:expr, $($arg:tt)+) => { ... };
}

Asserts that a boolean expression is true at compile-time.

Rust provides const blocks, which can be used flexibly within methods, but cannot be used directly at the top level. This macro serves as a helper to perform compile-time assertions outside of methods.