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Move Result::as_deref_mut

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David Tolnay 2021-12-30 10:24:23 -08:00
parent eda61d8d8a
commit 5aa8f91ff0
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1 changed files with 26 additions and 25 deletions
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51
library/core/src/result.rs
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@ -925,6 +925,32 @@ impl<T, E> Result<T, E> {
self.as_ref().map(|t| t.deref())
}
/// Converts from `Result<T, E>` (or `&mut Result<T, E>`) to `Result<&mut <T as DerefMut>::Target, &mut E>`.
///
/// Coerces the [`Ok`] variant of the original [`Result`] via [`DerefMut`](crate::ops::DerefMut)
/// and returns the new [`Result`].
///
/// # Examples
///
/// ```
/// let mut s = "HELLO".to_string();
/// let mut x: Result<String, u32> = Ok("hello".to_string());
/// let y: Result<&mut str, &mut u32> = Ok(&mut s);
/// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
///
/// let mut i = 42;
/// let mut x: Result<String, u32> = Err(42);
/// let y: Result<&mut str, &mut u32> = Err(&mut i);
/// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
/// ```
#[stable(feature = "inner_deref", since = "1.47.0")]
pub fn as_deref_mut(&mut self) -> Result<&mut T::Target, &mut E>
where
T: DerefMut,
{
self.as_mut().map(|t| t.deref_mut())
}
/////////////////////////////////////////////////////////////////////////
// Iterator constructors
/////////////////////////////////////////////////////////////////////////
@ -1532,31 +1558,6 @@ impl<T: Into<!>, E> Result<T, E> {
}
}
impl<T: DerefMut, E> Result<T, E> {
/// Converts from `Result<T, E>` (or `&mut Result<T, E>`) to `Result<&mut <T as DerefMut>::Target, &mut E>`.
///
/// Coerces the [`Ok`] variant of the original [`Result`] via [`DerefMut`](crate::ops::DerefMut)
/// and returns the new [`Result`].
///
/// # Examples
///
/// ```
/// let mut s = "HELLO".to_string();
/// let mut x: Result<String, u32> = Ok("hello".to_string());
/// let y: Result<&mut str, &mut u32> = Ok(&mut s);
/// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
///
/// let mut i = 42;
/// let mut x: Result<String, u32> = Err(42);
/// let y: Result<&mut str, &mut u32> = Err(&mut i);
/// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
/// ```
#[stable(feature = "inner_deref", since = "1.47.0")]
pub fn as_deref_mut(&mut self) -> Result<&mut T::Target, &mut E> {
self.as_mut().map(|t| t.deref_mut())
}
}
impl<T, E> Result<Option<T>, E> {
/// Transposes a `Result` of an `Option` into an `Option` of a `Result`.
///