Macro konst

macro_rules! konst {
    ($type:ty, $expr:expr $(,)*) => { ... };
}

Emulates the inline const feature(const{ ... }) in pre-1.79 versions.

As opposed to inline const, you must pass the type that the expression evaluates to.

Limitations

This can’t be used with expressions that reference generic parameters.

Example

use konst::{konst, eq_str};

const FOO: &str = "hello";

// By using `konst` here, the function is unconditionally evaluated at compile-time.
if konst!{bool, eq_str(FOO, "hi")} {
    panic!("The constants are equal, this wasn't supposed to happen!!");
}