This crate provides VariantCount derive macro for enum which adds to it the VARIANT_COUNT constant, containing count of enum variants.

The VariantCount usage example:

#[derive(VariantCount)]
enum Test {
    First(i32),
    Second(Option<String>),
    Third,
}

assert_eq!(Test::VARIANT_COUNT, 3);

If you're using Cargo, just add it to your Cargo.toml:

[dependencies]
variant_count = "1.2"

MIT