Change extensions traits to blanket impls

src/librustc/middle/typeck/check/method.rs

@@ -619,14 +619,15 @@ impl<'a, 'tcx> LookupContext<'a, 'tcx> {
 
         let tcx = self.tcx();
 
-        // It is illegal to invoke a method on a trait instance that
-        // refers to the `Self` type. An error will be reported by
-        // `enforce_object_limitations()` if the method refers to the
-        // `Self` type anywhere other than the receiver. Here, we use
-        // a substitution that replaces `Self` with the object type
-        // itself. Hence, a `&self` method will wind up with an
-        // argument type like `&Trait`.
-        let rcvr_substs = substs.with_self_ty(self_ty);
+        // It is illegal to create a trait object with methods which includes
+        // the Self type. An error will be reported when we coerce to a trait
+        // object if the method refers to the `Self` type. Substituting ty_err
+        // here allows compiler to soldier on.
+        //
+        // `confirm_candidate()` also relies upon this substitution
+        // for Self. (fix)
+        let rcvr_substs = substs.with_self_ty(ty::mk_err());
+
         let trait_ref = Rc::new(TraitRef {
             def_id: did,
             substs: rcvr_substs.clone()

src/libstd/io/buffered.rs

@@ -14,7 +14,7 @@
 
 use cmp;
 use collections::Collection;
-use io::{Reader, Writer, Stream, Buffer, DEFAULT_BUF_SIZE, IoResult, AsRefReader};
+use io::{Reader, Writer, Stream, Buffer, DEFAULT_BUF_SIZE, IoResult};
 use iter::ExactSize;
 use ops::Drop;
 use option::{Some, None, Option};
@@ -118,8 +118,6 @@ impl<R: Reader> Reader for BufferedReader<R> {
     }
 }
 
-impl<R: Reader> AsRefReader for BufferedReader<R> {}
-
 /// Wraps a Writer and buffers output to it
 ///
 /// It can be excessively inefficient to work directly with a `Writer`. For

src/libstd/io/extensions.rs

@@ -189,7 +189,6 @@ mod test {
             }
         }
     }
-    impl BytesReader for InitialZeroByteReader {}
 
     struct EofReader;
 
@@ -198,7 +197,6 @@ mod test {
             Err(io::standard_error(io::EndOfFile))
         }
     }
-    impl BytesReader for EofReader {}
 
     struct ErroringReader;
 
@@ -207,7 +205,6 @@ mod test {
             Err(io::standard_error(io::InvalidInput))
         }
     }
-    impl BytesReader for ErroringReader {}
 
     struct PartialReader {
         count: int,

src/libstd/io/mem.rs

@@ -17,7 +17,7 @@ use collections::Collection;
 use option::None;
 use result::{Err, Ok};
 use io;
-use io::{Reader, Writer, Seek, Buffer, IoError, SeekStyle, IoResult, AsRefReader, AsRefWriter};
+use io::{Reader, Writer, Seek, Buffer, IoError, SeekStyle, IoResult};
 use slice;
 use slice::AsSlice;
 use vec::Vec;
@@ -97,8 +97,6 @@ impl Writer for MemWriter {
     }
 }
 
-impl AsRefWriter for MemWriter {}
-
 /// Reads from an owned byte vector
 ///
 /// # Example
@@ -165,8 +163,6 @@ impl Reader for MemReader {
     }
 }
 
-impl AsRefReader for MemReader {}
-
 impl Seek for MemReader {
     #[inline]
     fn tell(&self) -> IoResult<u64> { Ok(self.pos as u64) }
@@ -313,8 +309,6 @@ impl<'a> Reader for BufReader<'a> {
      }
 }
 
-impl<'a> AsRefReader for BufReader<'a> {}
-
 impl<'a> Seek for BufReader<'a> {
     #[inline]
     fn tell(&self) -> IoResult<u64> { Ok(self.pos as u64) }

src/libstd/io/mod.rs

@@ -929,21 +929,29 @@ pub trait AsRefReader {
     ///
     /// This is useful to allow applying adaptors while still
     /// retaining ownership of the original value.
-    fn by_ref<'a>(&'a mut self) -> RefReader<'a, Self> {
+    fn by_ref<'a>(&'a mut self) -> RefReader<'a, Self>;
+}
+
+impl<T: Reader> AsRefReader for T {
+    fn by_ref<'a>(&'a mut self) -> RefReader<'a, T> {
         RefReader { inner: self }
     }
 }
 
 /// A reader which can be converted to bytes.
-pub trait BytesReader: Reader {
+pub trait BytesReader {
     /// Create an iterator that reads a single byte on
     /// each iteration, until EOF.
     ///
     /// # Error
     ///
     /// Any error other than `EndOfFile` that is produced by the underlying Reader
     /// is returned by the iterator and should be handled by the caller.
-    fn bytes<'r>(&'r mut self) -> extensions::Bytes<'r, Self> {
+    fn bytes<'r>(&'r mut self) -> extensions::Bytes<'r, Self>;
+}
+
+impl<T: Reader> BytesReader for T {
+    fn bytes<'r>(&'r mut self) -> extensions::Bytes<'r, T> {
         extensions::Bytes::new(self)
     }
 }
@@ -1284,7 +1292,11 @@ pub trait AsRefWriter {
     /// This is useful to allow applying wrappers while still
     /// retaining ownership of the original value.
     #[inline]
-    fn by_ref<'a>(&'a mut self) -> RefWriter<'a, Self> {
+    fn by_ref<'a>(&'a mut self) -> RefWriter<'a, Self>;
+}
+
+impl<T: Writer> AsRefWriter for T {
+    fn by_ref<'a>(&'a mut self) -> RefWriter<'a, T> {
         RefWriter { inner: self }
     }
 }