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Rollup merge of rust-lang#120160 - reitermarkus:nonzero-traits, r=dto…
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…lnay

Manually implement derived `NonZero` traits.

Step 3 as mentioned in rust-lang#100428 (review).

Manually implement the traits that would cause “borrow of layout constrained field with interior mutability” errors when switching to `NonZero<T>`.

r? `@dtolnay`
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matthiaskrgr authored Jan 22, 2024
2 parents 4512fa4 + 0e3035b commit c2db514
Showing 1 changed file with 101 additions and 8 deletions.
109 changes: 101 additions & 8 deletions library/core/src/num/nonzero.rs
Original file line number Diff line number Diff line change
@@ -1,6 +1,9 @@
//! Definitions of integer that is known not to equal zero.

use crate::cmp::Ordering;
use crate::fmt;
use crate::hash::{Hash, Hasher};
use crate::marker::StructuralPartialEq;
use crate::ops::{BitOr, BitOrAssign, Div, Neg, Rem};
use crate::str::FromStr;

Expand Down Expand Up @@ -31,13 +34,6 @@ pub trait ZeroablePrimitive: Sized + Copy + private::Sealed {
type NonZero;
}

#[unstable(
feature = "nonzero_internals",
reason = "implementation detail which may disappear or be replaced at any time",
issue = "none"
)]
pub(crate) type NonZero<T> = <T as ZeroablePrimitive>::NonZero;

macro_rules! impl_zeroable_primitive {
($NonZero:ident ( $primitive:ty )) => {
#[unstable(
Expand Down Expand Up @@ -71,6 +67,13 @@ impl_zeroable_primitive!(NonZeroI64(i64));
impl_zeroable_primitive!(NonZeroI128(i128));
impl_zeroable_primitive!(NonZeroIsize(isize));

#[unstable(
feature = "nonzero_internals",
reason = "implementation detail which may disappear or be replaced at any time",
issue = "none"
)]
pub(crate) type NonZero<T> = <T as ZeroablePrimitive>::NonZero;

macro_rules! impl_nonzero_fmt {
( #[$stability: meta] ( $( $Trait: ident ),+ ) for $Ty: ident ) => {
$(
Expand Down Expand Up @@ -128,7 +131,7 @@ macro_rules! nonzero_integer {
///
/// [null pointer optimization]: crate::option#representation
#[$stability]
#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
#[derive(Copy, Eq)]
#[repr(transparent)]
#[rustc_layout_scalar_valid_range_start(1)]
#[rustc_nonnull_optimization_guaranteed]
Expand Down Expand Up @@ -494,6 +497,96 @@ macro_rules! nonzero_integer {
}
}

#[$stability]
impl Clone for $Ty {
#[inline]
fn clone(&self) -> Self {
// SAFETY: The contained value is non-zero.
unsafe { Self(self.0) }
}
}

#[$stability]
impl PartialEq for $Ty {
#[inline]
fn eq(&self, other: &Self) -> bool {
self.0 == other.0
}

#[inline]
fn ne(&self, other: &Self) -> bool {
self.0 != other.0
}
}

#[unstable(feature = "structural_match", issue = "31434")]
impl StructuralPartialEq for $Ty {}

#[$stability]
impl PartialOrd for $Ty {
#[inline]
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
self.0.partial_cmp(&other.0)
}

#[inline]
fn lt(&self, other: &Self) -> bool {
self.0 < other.0
}

#[inline]
fn le(&self, other: &Self) -> bool {
self.0 <= other.0
}

#[inline]
fn gt(&self, other: &Self) -> bool {
self.0 > other.0
}

#[inline]
fn ge(&self, other: &Self) -> bool {
self.0 >= other.0
}
}

#[$stability]
impl Ord for $Ty {
#[inline]
fn cmp(&self, other: &Self) -> Ordering {
self.0.cmp(&other.0)
}

#[inline]
fn max(self, other: Self) -> Self {
// SAFETY: The maximum of two non-zero values is still non-zero.
unsafe { Self(self.0.max(other.0)) }
}

#[inline]
fn min(self, other: Self) -> Self {
// SAFETY: The minimum of two non-zero values is still non-zero.
unsafe { Self(self.0.min(other.0)) }
}

#[inline]
fn clamp(self, min: Self, max: Self) -> Self {
// SAFETY: A non-zero value clamped between two non-zero values is still non-zero.
unsafe { Self(self.0.clamp(min.0, max.0)) }
}
}

#[$stability]
impl Hash for $Ty {
#[inline]
fn hash<H>(&self, state: &mut H)
where
H: Hasher,
{
self.0.hash(state)
}
}

#[stable(feature = "from_nonzero", since = "1.31.0")]
impl From<$Ty> for $Int {
#[doc = concat!("Converts a `", stringify!($Ty), "` into an `", stringify!($Int), "`")]
Expand Down

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