rust-spec 0.2.0

Classification of types in accordance with the Rust specification
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65

//! Representation stability and trap/robustness classification.
//!
//! This module provides the marker types used by [`crate::RustSpec::Layout`].
//! Stability describes whether Rust guarantees the representation shape.
//! Robustness describes whether the represented value space has trap values that
//! require validity care.
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!()
    }
}