auto merge of #9464 : bmaxa/rust/master, r=cmr

I have tried this fix and it seems to work either with single or multiple trait inheritance.

trait Base:Base2 + Base3{
fn foo(&self);
}

trait Base2 {
fn baz(&self);
}

trait Base3{
fn root(&self);
}

trait Super: Base{
fn bar(&self);
}

struct X;

impl Base for X {
fn foo(&self) {
println("base foo");
}

}
impl Base2 for X {
fn baz(&self) {
println("base2 baz");
}

}
impl Base3 for X {
fn root(&self) {
println("base3 root");
}

}
impl Super for X {
fn bar(&self) {
println("super bar");
}
}

fn main() {
let n = X;
let s = &n as &Super;
s.bar();
s.foo(); // super bar
s.baz();
s.root();
}

bmaxa@maxa:~/examples/rust$ rustc error.rs
bmaxa@maxa:~/examples/rust$ ./error 
super bar
base foo
base2 baz
base3 root

src/test/run-pass/issue-9394-inherited-trait-calls.rs

@@ -0,0 +1,61 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+trait Base: Base2 + Base3{
+    fn foo(&self) -> ~str;
+}
+
+trait Base2: Base3{
+    fn baz(&self) -> ~str;
+}
+
+trait Base3{
+    fn root(&self) -> ~str;
+}
+
+trait Super: Base{
+    fn bar(&self) -> ~str;
+}
+
+struct X;
+
+impl Base for X {
+    fn foo(&self) -> ~str{
+        ~"base foo"
+    }
+
+}
+
+impl Base2 for X {
+    fn baz(&self) -> ~str{
+        ~"base2 baz"
+    }
+}
+
+impl Base3 for X {
+    fn root(&self) -> ~str{
+        ~"base3 root"
+    }
+}
+
+impl Super for X {
+    fn bar(&self) -> ~str{
+        ~"super bar"
+    }
+}
+
+pub fn main() {
+    let n = X;
+    let s = &n as &Super;
+    assert_eq!(s.bar(),~"super bar");
+    assert_eq!(s.foo(),~"base foo");
+    assert_eq!(s.baz(),~"base2 baz");
+    assert_eq!(s.root(),~"base3 root");
+}