add array from_ref
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@ -19,6 +19,20 @@ mod iter;
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#[unstable(feature = "array_value_iter", issue = "65798")]
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pub use iter::IntoIter;
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/// Converts a reference to `T` into a reference to an array of length 1 (without copying).
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#[unstable(feature = "array_from_ref", issue = "none")]
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pub fn from_ref<T>(s: &T) -> &[T; 1] {
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// SAFETY: Converting `&T` to `&[T; 1]` is sound.
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unsafe { &*(s as *const T).cast::<[T; 1]>() }
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}
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/// Converts a mutable reference to `T` into a mutable reference to an array of length 1 (without copying).
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#[unstable(feature = "array_from_ref", issue = "none")]
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pub fn from_mut<T>(s: &mut T) -> &mut [T; 1] {
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// SAFETY: Converting `&mut T` to `&mut [T; 1]` is sound.
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unsafe { &mut *(s as *mut T).cast::<[T; 1]>() }
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}
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/// Utility trait implemented only on arrays of fixed size
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///
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/// This trait can be used to implement other traits on fixed-size arrays
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@ -1,4 +1,4 @@
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use core::array::{FixedSizeArray, IntoIter};
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use core::array::{self, FixedSizeArray, IntoIter};
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use core::convert::TryFrom;
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#[test]
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@ -19,6 +19,21 @@ fn fixed_size_array() {
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assert_eq!(FixedSizeArray::as_mut_slice(&mut empty_zero_sized).len(), 0);
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}
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#[test]
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fn array_from_ref() {
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let value: String = "Hello World!".into();
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let arr: &[String; 1] = array::from_ref(&value);
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assert_eq!(&[value.clone()], arr);
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}
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#[test]
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fn array_from_mut() {
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let mut value: String = "Hello World".into();
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let arr: &mut [String; 1] = array::from_mut(&mut value);
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arr[0].push_str("!");
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assert_eq!(&value, "Hello World!");
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}
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#[test]
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fn array_try_from() {
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macro_rules! test {
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@ -1,5 +1,6 @@
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#![feature(alloc_layout_extra)]
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#![feature(array_chunks)]
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#![feature(array_from_ref)]
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#![feature(array_methods)]
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#![feature(array_map)]
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#![feature(array_windows)]
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