rust-spec 0.5.1

Classification of types in accordance with the Rust specification
Documentation 
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//! Representation stability and trap/robustness classification.
//!
//! Stability describes whether Rust guarantees a type's layout whereas robustness describes
//! whether the represented value space has invalid bit patterns (i.e. trap values).
//!
//! This module provides the marker types used by [`crate::RustSpec::Layout`] and [`crate::RustSpec::Trap`].
use core::ops::Add;

use crate::{Stable, Unstable};

/// Closed family of representation-stability classifications.
#[sealed::sealed]
pub trait LayoutKind {}

/// Marker for a robust type that does not require validity conversion.
pub enum Robust {}

/// Marker for a non-robust type that is still transmuted by the ABI layer.
pub enum NonRobust {}

#[sealed::sealed]
impl LayoutKind for Stable {}

#[sealed::sealed]
impl LayoutKind for Unstable {}

impl<K> Add<K> for NonRobust {
    type Output = Self;

    fn add(self, _: K) -> Self::Output {
        unreachable!()
    }
}

impl<K> Add<K> for Robust {
    type Output = K;

    fn add(self, _: K) -> Self::Output {
        unreachable!()
    }
}

impl<K> Add<K> for Unstable {
    type Output = Self;

    fn add(self, _: K) -> Self::Output {
        unreachable!()
    }
}

impl Add<Unstable> for Stable {
    type Output = Unstable;

    fn add(self, _: Unstable) -> Self::Output {
        unreachable!()
    }
}

impl Add for Stable {
    type Output = Self;

    fn add(self, _: Self) -> Self::Output {
        unreachable!()
    }
}