// check-pass // Verify that variant count intrinsic can still evaluate for types like `Option<T>`. #![feature(variant_count)] pub struct GetVariantCount<T>(T); impl<T> GetVariantCount<T> { pub const VALUE: usize = std::mem::variant_count::<T>(); } const fn check_variant_count<T>() -> bool { matches!(GetVariantCount::<Option<T>>::VALUE, GetVariantCount::<Option<()>>::VALUE) } fn main() { assert!(check_variant_count::<()>()); }