}
impl dyn Any {
- /// Returns `true` if the boxed type is the same as `T`.
+ /// Returns `true` if the inner type is the same as `T`.
///
/// # Examples
///
t == concrete
}
- /// Returns some reference to the boxed value if it is of type `T`, or
+ /// Returns some reference to the inner value if it is of type `T`, or
/// `None` if it isn't.
///
/// # Examples
// SAFETY: just checked whether we are pointing to the correct type, and we can rely on
// that check for memory safety because we have implemented Any for all types; no other
// impls can exist as they would conflict with our impl.
- unsafe { Some(&*(self as *const dyn Any as *const T)) }
+ unsafe { Some(self.downcast_ref_unchecked()) }
} else {
None
}
}
- /// Returns some mutable reference to the boxed value if it is of type `T`, or
+ /// Returns some mutable reference to the inner value if it is of type `T`, or
/// `None` if it isn't.
///
/// # Examples
// SAFETY: just checked whether we are pointing to the correct type, and we can rely on
// that check for memory safety because we have implemented Any for all types; no other
// impls can exist as they would conflict with our impl.
- unsafe { Some(&mut *(self as *mut dyn Any as *mut T)) }
+ unsafe { Some(self.downcast_mut_unchecked()) }
} else {
None
}
}
+
+ /// Returns a reference to the inner value as type `dyn T`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(downcast_unchecked)]
+ ///
+ /// use std::any::Any;
+ ///
+ /// let x: Box<dyn Any> = Box::new(1_usize);
+ ///
+ /// unsafe {
+ /// assert_eq!(*x.downcast_ref_unchecked::<usize>(), 1);
+ /// }
+ /// ```
+ ///
+ /// # Safety
+ ///
+ /// The contained value must be of type `T`. Calling this method
+ /// with the incorrect type is *undefined behavior*.
+ #[unstable(feature = "downcast_unchecked", issue = "90850")]
+ #[inline]
+ pub unsafe fn downcast_ref_unchecked<T: Any>(&self) -> &T {
+ debug_assert!(self.is::<T>());
+ // SAFETY: caller guarantees that T is the correct type
+ unsafe { &*(self as *const dyn Any as *const T) }
+ }
+
+ /// Returns a mutable reference to the inner value as type `dyn T`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(downcast_unchecked)]
+ ///
+ /// use std::any::Any;
+ ///
+ /// let mut x: Box<dyn Any> = Box::new(1_usize);
+ ///
+ /// unsafe {
+ /// *x.downcast_mut_unchecked::<usize>() += 1;
+ /// }
+ ///
+ /// assert_eq!(*x.downcast_ref::<usize>().unwrap(), 2);
+ /// ```
+ ///
+ /// # Safety
+ ///
+ /// The contained value must be of type `T`. Calling this method
+ /// with the incorrect type is *undefined behavior*.
+ #[unstable(feature = "downcast_unchecked", issue = "90850")]
+ #[inline]
+ pub unsafe fn downcast_mut_unchecked<T: Any>(&mut self) -> &mut T {
+ debug_assert!(self.is::<T>());
+ // SAFETY: caller guarantees that T is the correct type
+ unsafe { &mut *(self as *mut dyn Any as *mut T) }
+ }
}
impl dyn Any + Send {
- /// Forwards to the method defined on the type `Any`.
+ /// Forwards to the method defined on the type `dyn Any`.
///
/// # Examples
///
<dyn Any>::is::<T>(self)
}
- /// Forwards to the method defined on the type `Any`.
+ /// Forwards to the method defined on the type `dyn Any`.
///
/// # Examples
///
<dyn Any>::downcast_ref::<T>(self)
}
- /// Forwards to the method defined on the type `Any`.
+ /// Forwards to the method defined on the type `dyn Any`.
///
/// # Examples
///
pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
<dyn Any>::downcast_mut::<T>(self)
}
+
+ /// Forwards to the method defined on the type `dyn Any`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(downcast_unchecked)]
+ ///
+ /// use std::any::Any;
+ ///
+ /// let x: Box<dyn Any> = Box::new(1_usize);
+ ///
+ /// unsafe {
+ /// assert_eq!(*x.downcast_ref_unchecked::<usize>(), 1);
+ /// }
+ /// ```
+ ///
+ /// # Safety
+ ///
+ /// Same as the method on the type `dyn Any`.
+ #[unstable(feature = "downcast_unchecked", issue = "90850")]
+ #[inline]
+ pub unsafe fn downcast_ref_unchecked<T: Any>(&self) -> &T {
+ // SAFETY: guaranteed by caller
+ unsafe { <dyn Any>::downcast_ref_unchecked::<T>(self) }
+ }
+
+ /// Forwards to the method defined on the type `dyn Any`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(downcast_unchecked)]
+ ///
+ /// use std::any::Any;
+ ///
+ /// let mut x: Box<dyn Any> = Box::new(1_usize);
+ ///
+ /// unsafe {
+ /// *x.downcast_mut_unchecked::<usize>() += 1;
+ /// }
+ ///
+ /// assert_eq!(*x.downcast_ref::<usize>().unwrap(), 2);
+ /// ```
+ ///
+ /// # Safety
+ ///
+ /// Same as the method on the type `dyn Any`.
+ #[unstable(feature = "downcast_unchecked", issue = "90850")]
+ #[inline]
+ pub unsafe fn downcast_mut_unchecked<T: Any>(&mut self) -> &mut T {
+ // SAFETY: guaranteed by caller
+ unsafe { <dyn Any>::downcast_mut_unchecked::<T>(self) }
+ }
}
impl dyn Any + Send + Sync {
pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
<dyn Any>::downcast_mut::<T>(self)
}
+
+ /// Forwards to the method defined on the type `Any`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(downcast_unchecked)]
+ ///
+ /// use std::any::Any;
+ ///
+ /// let x: Box<dyn Any> = Box::new(1_usize);
+ ///
+ /// unsafe {
+ /// assert_eq!(*x.downcast_ref_unchecked::<usize>(), 1);
+ /// }
+ /// ```
+ #[unstable(feature = "downcast_unchecked", issue = "90850")]
+ #[inline]
+ pub unsafe fn downcast_ref_unchecked<T: Any>(&self) -> &T {
+ // SAFETY: guaranteed by caller
+ unsafe { <dyn Any>::downcast_ref_unchecked::<T>(self) }
+ }
+
+ /// Forwards to the method defined on the type `Any`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(downcast_unchecked)]
+ ///
+ /// use std::any::Any;
+ ///
+ /// let mut x: Box<dyn Any> = Box::new(1_usize);
+ ///
+ /// unsafe {
+ /// *x.downcast_mut_unchecked::<usize>() += 1;
+ /// }
+ ///
+ /// assert_eq!(*x.downcast_ref::<usize>().unwrap(), 2);
+ /// ```
+ #[unstable(feature = "downcast_unchecked", issue = "90850")]
+ #[inline]
+ pub unsafe fn downcast_mut_unchecked<T: Any>(&mut self) -> &mut T {
+ // SAFETY: guaranteed by caller
+ unsafe { <dyn Any>::downcast_mut_unchecked::<T>(self) }
+ }
}
///////////////////////////////////////////////////////////////////////////////