#[lang = "discriminant_kind"]pub trait DiscriminantKind {
    type Discriminant: Clone + PartialEq<Self::Discriminant> + Eq + Send + Copy + Sync + Unpin + Debug + Hash;
}
Compiler-internal trait used to indicate the type of enum discriminants.
This trait is automatically implemented for every type and does not add any guarantees to mem::Discriminant. It is undefined behavior to transmute between DiscriminantKind::Discriminant and mem::Discriminant.
type Discriminant: Clone + PartialEq<Self::Discriminant> + Eq + Send + Copy + Sync + Unpin + Debug + HashThe type of the discriminant, which must satisfy the trait bounds required by mem::Discriminant.
    © 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
    https://doc.rust-lang.org/std/marker/trait.DiscriminantKind.html