Implement DerefImm for Rc and DerefImm/DerefMut for RefCell's Ref/RefMut.

Author: eddyb

src/libstd/cell.rs

@@ -15,7 +15,7 @@ use clone::{Clone, DeepClone};
 use cmp::Eq;
 use fmt;
 use kinds::{marker, Pod};
-use ops::Drop;
+use ops::{Deref, DerefMut, Drop};
 use option::{None, Option, Some};
 
 /// A mutable memory location that admits only `Pod` data.
@@ -258,6 +258,13 @@ impl<'b, T> Ref<'b, T> {
     }
 }
 
+impl<'b, T> Deref<T> for Ref<'b, T> {
+    #[inline]
+    fn deref<'a>(&'a self) -> &'a T {
+        &self.parent.value
+    }
+}
+
 /// Wraps a mutable borrowed reference to a value in a `RefCell` box.
 pub struct RefMut<'b, T> {
     priv parent: &'b mut RefCell<T>
@@ -279,6 +286,20 @@ impl<'b, T> RefMut<'b, T> {
     }
 }
 
+impl<'b, T> Deref<T> for RefMut<'b, T> {
+    #[inline]
+    fn deref<'a>(&'a self) -> &'a T {
+        &self.parent.value
+    }
+}
+
+impl<'b, T> DerefMut<T> for RefMut<'b, T> {
+    #[inline]
+    fn deref_mut<'a>(&'a mut self) -> &'a mut T {
+        &mut self.parent.value
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;

src/libstd/rc.rs

@@ -27,7 +27,7 @@ use cast::transmute;
 use clone::{Clone, DeepClone};
 use cmp::{Eq, Ord};
 use kinds::marker;
-use ops::Drop;
+use ops::{Deref, Drop};
 use option::{Option, Some, None};
 use ptr;
 use rt::global_heap::exchange_free;
@@ -78,6 +78,14 @@ impl<T> Rc<T> {
     }
 }
 
+impl<T> Deref<T> for Rc<T> {
+    /// Borrow the value contained in the reference-counted box
+    #[inline(always)]
+    fn deref<'a>(&'a self) -> &'a T {
+        unsafe { &(*self.ptr).value }
+    }
+}
+
 #[unsafe_destructor]
 impl<T> Drop for Rc<T> {
     fn drop(&mut self) {