auto merge of #18467 : japaric/rust/eq, r=alexcrichton

`eq`, `ne`, `cmp`, etc methods now require one less level of indirection when dealing with `&str`/`&[T]`

``` rust
"foo".ne(&"bar") -> "foo".ne("bar")
slice.cmp(&another_slice) -> slice.cmp(another_slice)
// slice and another_slice have type `&[T]`
```

[breaking-change]

1 files changed, 40 insertions, 0 deletions

diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index de98bc63183..d1fc921ffda 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -61,12 +61,16 @@ impl<T: Clone> Clone for Box<T> {
     }
 }
 
+// NOTE(stage0): remove impl after a snapshot
+#[cfg(stage0)]
 impl<T:PartialEq> PartialEq for Box<T> {
     #[inline]
     fn eq(&self, other: &Box<T>) -> bool { *(*self) == *(*other) }
     #[inline]
     fn ne(&self, other: &Box<T>) -> bool { *(*self) != *(*other) }
 }
+// NOTE(stage0): remove impl after a snapshot
+#[cfg(stage0)]
 impl<T:PartialOrd> PartialOrd for Box<T> {
     #[inline]
     fn partial_cmp(&self, other: &Box<T>) -> Option<Ordering> {
@@ -81,14 +85,50 @@ impl<T:PartialOrd> PartialOrd for Box<T> {
     #[inline]
     fn gt(&self, other: &Box<T>) -> bool { *(*self) > *(*other) }
 }
+// NOTE(stage0): remove impl after a snapshot
+#[cfg(stage0)]
 impl<T: Ord> Ord for Box<T> {
     #[inline]
     fn cmp(&self, other: &Box<T>) -> Ordering {
         (**self).cmp(&**other)
     }
 }
+// NOTE(stage0): remove impl after a snapshot
+#[cfg(stage0)]
 impl<T: Eq> Eq for Box<T> {}
 
+#[cfg(not(stage0))]  // NOTE(stage0): remove cfg after a snapshot
+impl<Sized? T: PartialEq> PartialEq for Box<T> {
+    #[inline]
+    fn eq(&self, other: &Box<T>) -> bool { PartialEq::eq(&**self, &**other) }
+    #[inline]
+    fn ne(&self, other: &Box<T>) -> bool { PartialEq::ne(&**self, &**other) }
+}
+#[cfg(not(stage0))]  // NOTE(stage0): remove cfg after a snapshot
+impl<Sized? T: PartialOrd> PartialOrd for Box<T> {
+    #[inline]
+    fn partial_cmp(&self, other: &Box<T>) -> Option<Ordering> {
+        PartialOrd::partial_cmp(&**self, &**other)
+    }
+    #[inline]
+    fn lt(&self, other: &Box<T>) -> bool { PartialOrd::lt(&**self, &**other) }
+    #[inline]
+    fn le(&self, other: &Box<T>) -> bool { PartialOrd::le(&**self, &**other) }
+    #[inline]
+    fn ge(&self, other: &Box<T>) -> bool { PartialOrd::ge(&**self, &**other) }
+    #[inline]
+    fn gt(&self, other: &Box<T>) -> bool { PartialOrd::gt(&**self, &**other) }
+}
+#[cfg(not(stage0))]  // NOTE(stage0): remove cfg after a snapshot
+impl<Sized? T: Ord> Ord for Box<T> {
+    #[inline]
+    fn cmp(&self, other: &Box<T>) -> Ordering {
+        Ord::cmp(&**self, &**other)
+    }
+}
+#[cfg(not(stage0))]  // NOTE(stage0): remove cfg after a snapshot
+impl<Sized? T: Eq> Eq for Box<T> {}
+
 /// Extension methods for an owning `Any` trait object.
 #[unstable = "post-DST and coherence changes, this will not be a trait but \
               rather a direct `impl` on `Box<Any>`"]