`mut` in a default method parameter list doesn't parse

[huonw]

#[allow(default_methods)];

trait Foo {
    fn foo(mut v: int) {}
}

fn main() {}

trait-dm-mut.rs:4:10: 4:11 error: found `mut` in ident position
trait-dm-mut.rs:4     fn foo(mut v: int) {}
                            ^
trait-dm-mut.rs:4:15: 4:16 error: expected `,` but found `v`
trait-dm-mut.rs:4     fn foo(mut v: int) {}
                                 ^

This is presumably just a parser issue; the following works:

trait Foo {
    fn foo(v: int);
}
impl Foo for int { fn foo(mut v: int) {} }

fn main() {}