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From: cleanup

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Marijn Schouten 2025-10-06 12:19:50 +00:00
parent 4d38622e8b
commit 163a4b4caf
1 changed files with 38 additions and 49 deletions
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87
library/core/src/convert/num.rs
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@ -39,62 +39,51 @@ impl_float_to_int!(f32 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i12
impl_float_to_int!(f64 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
impl_float_to_int!(f128 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
// Conversion traits for primitive integer and float types
// Conversions T -> T are covered by a blanket impl and therefore excluded
// Some conversions from and to usize/isize are not implemented due to portability concerns
macro_rules! impl_from {
(bool => $Int:ty $(,)?) => {
impl_from!(
bool => $Int,
#[stable(feature = "from_bool", since = "1.28.0")],
concat!(
"Converts a [`bool`] to [`", stringify!($Int), "`] losslessly.\n",
"The resulting value is `0` for `false` and `1` for `true` values.\n",
"\n",
"# Examples\n",
"\n",
"```\n",
"assert_eq!(", stringify!($Int), "::from(true), 1);\n",
"assert_eq!(", stringify!($Int), "::from(false), 0);\n",
"```\n",
),
);
};
($Small:ty => $Large:ty, #[$attr:meta] $(,)?) => {
impl_from!(
$Small => $Large,
#[$attr],
concat!("Converts [`", stringify!($Small), "`] to [`", stringify!($Large), "`] losslessly."),
);
};
($Small:ty => $Large:ty, #[$attr:meta], $doc:expr $(,)?) => {
#[$attr]
/// Implement `From<bool>` for integers
macro_rules! impl_from_bool {
($($int:ty)*) => {$(
#[stable(feature = "from_bool", since = "1.28.0")]
#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
impl const From<$Small> for $Large {
// Rustdocs on the impl block show a "[+] show undocumented items" toggle.
// Rustdocs on functions do not.
#[doc = $doc]
impl const From<bool> for $int {
/// Converts from [`bool`] to
#[doc = concat!("[`", stringify!($int), "`]")]
/// , by turning `false` into `0` and `true` into `1`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($int), "::from(false), 0);")]
///
#[doc = concat!("assert_eq!(", stringify!($int), "::from(true), 1);")]
/// ```
#[inline(always)]
fn from(small: $Small) -> Self {
small as Self
fn from(b: bool) -> Self {
b as Self
}
}
};
)*}
}
// boolean -> integer
impl_from!(bool => u8);
impl_from!(bool => u16);
impl_from!(bool => u32);
impl_from!(bool => u64);
impl_from!(bool => u128);
impl_from!(bool => usize);
impl_from!(bool => i8);
impl_from!(bool => i16);
impl_from!(bool => i32);
impl_from!(bool => i64);
impl_from!(bool => i128);
impl_from!(bool => isize);
impl_from_bool!(u8 u16 u32 u64 u128 usize);
impl_from_bool!(i8 i16 i32 i64 i128 isize);
/// Implement `From<$small>` for `$large`
macro_rules! impl_from {
($small:ty => $large:ty, #[$attr:meta]) => {
#[$attr]
#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
impl const From<$small> for $large {
#[doc = concat!("Converts from [`", stringify!($small), "`] to [`", stringify!($large), "`] losslessly.")]
#[inline(always)]
fn from(small: $small) -> Self {
debug_assert!(<$large>::MIN as i128 <= <$small>::MIN as i128);
debug_assert!(<$small>::MAX as u128 <= <$large>::MAX as u128);
small as Self
}
}
}
}
// unsigned integer -> unsigned integer
impl_from!(u8 => u16, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);