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/*! Tracking mutability through the trait system.

This module enables the pointer structure system to enforce
!*/

/// A marker trait for distinguishing `*const` vs `*mut` when working with
/// structs, rather than raw pointers.
pub trait Mutability: 'static + seal::Sealed {}

/// An immutable pointer.
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub struct Const;

impl Mutability for Const {
}

impl seal::Sealed for Const {
}

/// A mutable pointer. Contexts with a `Mutable` may lower to `Immutable`, then
/// re-raise to `Mutable`; contexts with `Immutable` may not raise to `Mutable`
/// on their own.
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub struct Mut;

impl Mutability for Mut {
}

impl seal::Sealed for Mut {
}

#[doc(hidden)]
mod seal {
	#[doc(hidden)]
	pub trait Sealed {}
}