Add implementations for Any + Send + Sync

Implement `is`, `downcast_ref`, `downcast_mut` and `Debug` for
`Any + Send + Sync`.

Author: jsgf

src/libcore/any.rs

@@ -136,6 +136,13 @@ impl fmt::Debug for Any + Send {
     }
 }
 
+#[stable(feature = "any_send_sync_methods", since = "1.28.0")]
+impl fmt::Debug for Any + Send + Sync {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad("Any")
+    }
+}
+
 impl Any {
     /// Returns `true` if the boxed type is the same as `T`.
     ///
@@ -325,6 +332,89 @@ impl Any+Send {
     }
 }
 
+impl Any+Send+Sync {
+    /// Forwards to the method defined on the type `Any`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn is_string(s: &(Any + Send + Sync)) {
+    ///     if s.is::<String>() {
+    ///         println!("It's a string!");
+    ///     } else {
+    ///         println!("Not a string...");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     is_string(&0);
+    ///     is_string(&"cookie monster".to_string());
+    /// }
+    /// ```
+    #[stable(feature = "any_send_sync_methods", since = "1.28.0")]
+    #[inline]
+    pub fn is<T: Any>(&self) -> bool {
+        Any::is::<T>(self)
+    }
+
+    /// Forwards to the method defined on the type `Any`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn print_if_string(s: &(Any + Send)) {
+    ///     if let Some(string) = s.downcast_ref::<String>() {
+    ///         println!("It's a string({}): '{}'", string.len(), string);
+    ///     } else {
+    ///         println!("Not a string...");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     print_if_string(&0);
+    ///     print_if_string(&"cookie monster".to_string());
+    /// }
+    /// ```
+    #[stable(feature = "any_send_sync_methods", since = "1.28.0")]
+    #[inline]
+    pub fn downcast_ref<T: Any>(&self) -> Option<&T> {
+        Any::downcast_ref::<T>(self)
+    }
+
+    /// Forwards to the method defined on the type `Any`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn modify_if_u32(s: &mut (Any+ Send)) {
+    ///     if let Some(num) = s.downcast_mut::<u32>() {
+    ///         *num = 42;
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     let mut x = 10u32;
+    ///     let mut s = "starlord".to_string();
+    ///
+    ///     modify_if_u32(&mut x);
+    ///     modify_if_u32(&mut s);
+    ///
+    ///     assert_eq!(x, 42);
+    ///     assert_eq!(&s, "starlord");
+    /// }
+    /// ```
+    #[stable(feature = "any_send_sync_methods", since = "1.28.0")]
+    #[inline]
+    pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
+        Any::downcast_mut::<T>(self)
+    }
+}
 
 ///////////////////////////////////////////////////////////////////////////////
 // TypeID and its methods