auto merge of #8820 : alexcrichton/rust/no-io-writer, r=brson

At the same time, this updates the TyVisitor to use a mutable self because it's
probably going to be mutating state as it goes along anyway.

src/librustc/middle/ty.rs

@@ -4572,7 +4572,7 @@ pub fn visitor_object_ty(tcx: ctxt,
                  trait_ref.def_id,
                  trait_ref.substs.clone(),
                  RegionTraitStore(region),
-                 ast::m_imm,
+                 ast::m_mutbl,
                  EmptyBuiltinBounds())))
 }
 

src/libstd/logging.rs

@@ -41,16 +41,10 @@ pub fn console_off() {
 #[lang="log_type"]
 #[allow(missing_doc)]
 pub fn log_type<T>(_level: u32, object: &T) {
-    use io;
-    use repr;
-    use str;
-
-    let bytes = do io::with_bytes_writer |writer| {
-        repr::write_repr(writer, object);
-    };
+    use sys;
 
     // XXX: Bad allocation
-    let msg = str::from_bytes(bytes);
+    let msg = sys::log_str(object);
     newsched_log_str(msg);
 }