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impl Deref instead of Index

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This commit is contained in:
F001 2018-05-28 07:52:39 +08:00
parent 4d99957ce3
commit bdf86300b4
2 changed files with 9 additions and 10 deletions
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18
src/libcore/cell.rs
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@ -200,9 +200,8 @@ use cmp::Ordering;
use fmt::{self, Debug, Display};
use marker::Unsize;
use mem;
use ops::{Deref, DerefMut, CoerceUnsized, Index};
use ops::{Deref, DerefMut, CoerceUnsized};
use ptr;
use slice::SliceIndex;
/// A mutable memory location.
///
@ -510,8 +509,9 @@ impl<T: ?Sized> Cell<T> {
/// use std::cell::Cell;
/// let slice: &mut [i32] = &mut [1,2,3];
/// let cell_slice: &Cell<[i32]> = Cell::from_mut(slice);
/// assert_eq!(cell_slice.len(), 3);
/// let slice_cell : &[Cell<i32>] = &cell_slice[..];
/// assert_eq!(slice_cell.len(), 3)
/// assert_eq!(slice_cell.len(), 3);
/// ```
#[inline]
#[unstable(feature = "as_cell", issue="43038")]
@ -546,15 +546,13 @@ impl<T: Default> Cell<T> {
impl<T: CoerceUnsized<U>, U> CoerceUnsized<Cell<U>> for Cell<T> {}
#[unstable(feature = "as_cell", issue="43038")]
impl<T, I> Index<I> for Cell<[T]>
where
I: SliceIndex<[Cell<T>]>
{
type Output = I::Output;
impl<T> Deref for Cell<[T]> {
type Target = [Cell<T>];
fn index(&self, index: I) -> &Self::Output {
#[inline]
fn deref(&self) -> &[Cell<T>] {
unsafe {
Index::index(&*(self as *const Cell<[T]> as *const [Cell<T>]), index)
&*(self as *const Cell<[T]> as *const [Cell<T>])
}
}
}

1
src/test/run-pass/rfc-1789-as-cell/from-mut.rs
View file

@ -15,6 +15,7 @@ use std::cell::Cell;
fn main() {
let slice: &mut [i32] = &mut [1,2,3];
let cell_slice: &Cell<[i32]> = Cell::from_mut(slice);
assert_eq!(cell_slice.len(), 3);
let sub_slice : &[Cell<i32>] = &cell_slice[1..];
assert_eq!(sub_slice.len(), 2);
}