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From<NonZero*> impls for wider NonZero types #66277

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Merged
merged 5 commits into from
Dec 10, 2019
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Merged

From<NonZero*> impls for wider NonZero types #66277

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7bf66d9
From<NonZero*> impls for wider NonZero types
Nov 10, 2019
ae2b192
remove irrelevant Safety section
Nov 10, 2019
9f88273
add NonZeroU16 -> NonZeroUsize and NonZeroI16 -> NonZeroIsize
Nov 11, 2019
947772f
update version metadata
Nov 11, 2019
8f6a062
move from non zero impls to `libcore/convert/num.rs`
Dec 8, 2019
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70 changes: 70 additions & 0 deletions src/libcore/num/mod.rs
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Expand Up @@ -5250,3 +5250,73 @@ impl_from! { u32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0"

// Float -> Float
impl_from! { f32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }

// Conversion traits for non-zero integer types
macro_rules! nzint_impl_from {
($Small: ty, $Large: ty, #[$attr:meta], $doc: expr) => {
#[$attr]
#[doc = $doc]
impl From<$Small> for $Large {
/// Widens a non-zero integer without checking the value is zero.
///
/// # Safety
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Safety section here is irrelevant, because the input type already guarantees the value is non-zero.

///
/// The value is assumed to be non-zero.
#[inline]
fn from(small: $Small) -> $Large {
unsafe {
<$Large>::new_unchecked(small.get().into())
}
}
}
};
($Small: ty, $Large: ty, #[$attr:meta]) => {
nzint_impl_from!($Small,
$Large,
#[$attr],
concat!("Converts `",
stringify!($Small),
"` to `",
stringify!($Large),
"` losslessly."));
}
}

// Non-zero Unsigned -> Non-zero Unsigned
nzint_impl_from! { NonZeroU8, NonZeroU16, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU8, NonZeroU32, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU8, NonZeroU64, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU8, NonZeroU128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU8, NonZeroUsize, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU16, NonZeroU32, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU16, NonZeroU64, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU16, NonZeroU128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU32, NonZeroU64, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU32, NonZeroU128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU64, NonZeroU128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }

// Non-zero Signed -> Non-zero Signed
nzint_impl_from! { NonZeroI8, NonZeroI16, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI8, NonZeroI32, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI8, NonZeroI64, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI8, NonZeroI128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI8, NonZeroIsize, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI16, NonZeroI32, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI16, NonZeroI64, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI16, NonZeroI128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI32, NonZeroI64, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI32, NonZeroI128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroI64, NonZeroI128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }

// NonZero UnSigned -> Non-zero Signed
nzint_impl_from! { NonZeroU8, NonZeroI16, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU8, NonZeroI32, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU8, NonZeroI64, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU8, NonZeroI128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU8, NonZeroIsize, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU16, NonZeroI32, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU16, NonZeroI64, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU16, NonZeroI128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU32, NonZeroI64, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU32, NonZeroI128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }
nzint_impl_from! { NonZeroU64, NonZeroI128, #[unstable(feature = "lossless_non_zero_int_conv", issue = "66196")] }