auto merge of #17464 : pcwalton/rust/inherent-methods-on-equal-footing, r=nikomatsakis

over inherent methods accessible via more autoderefs.

This simplifies the trait matching algorithm. It breaks code like:

    impl Foo {
        fn foo(self) {
            // before this change, this will be called
        }
    }

    impl<'a,'b,'c> Trait for &'a &'b &'c Foo {
        fn foo(self) {
            // after this change, this will be called
        }
    }

    fn main() {
        let x = &(&(&Foo));
        x.foo();
    }

To explicitly indicate that you wish to call the inherent method, perform
explicit dereferences. For example:

    fn main() {
        let x = &(&(&Foo));
        (***x).foo();
    }

Part of #17282.

[breaking-change]

r? @nikomatsakis

1 files changed, 11 insertions, 4 deletions

diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index ff508c802d8..81e05648567 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -946,11 +946,14 @@ pub trait Reader {
 }
 
 impl<'a> Reader for Box<Reader+'a> {
-    fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> { self.read(buf) }
+    fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> {
+        let reader: &mut Reader = &mut **self;
+        reader.read(buf)
+    }
 }
 
 impl<'a> Reader for &'a mut Reader+'a {
-    fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> { self.read(buf) }
+    fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> { (*self).read(buf) }
 }
 
 /// Returns a slice of `v` between `start` and `end`.
@@ -1281,10 +1284,14 @@ pub trait Writer {
 
 impl<'a> Writer for Box<Writer+'a> {
     #[inline]
-    fn write(&mut self, buf: &[u8]) -> IoResult<()> { self.write(buf) }
+    fn write(&mut self, buf: &[u8]) -> IoResult<()> {
+        (&mut **self).write(buf)
+    }
 
     #[inline]
-    fn flush(&mut self) -> IoResult<()> { self.flush() }
+    fn flush(&mut self) -> IoResult<()> {
+        (&mut **self).flush()
+    }
 }
 
 impl<'a> Writer for &'a mut Writer+'a {