Error message suggests illegal syntax for method receiver

[Havvy]

// Playpen Link: http://is.gd/2baYh8
struct Struct;

impl Struct {
    fn foo(&mut self) {
        (&mut self).bar();
    }

    fn bar(&mut self) {}
}

fn main () {}

Output:

<anon>:5:15: 5:19 error: cannot borrow immutable argument `self` as mutable
<anon>:5         (&mut self).bar();
                       ^~~~
<anon>:4:17: 4:21 help: to make the argument mutable, use `mut` as shown:
<anon>:      fn foo(&mut mut self) {
error: aborting due to previous error
playpen: application terminated with error code 101

[durka]

The argument self is of type &mut Self but it is, itself, immutable. You can't redefine self to point at somebody else. The rest of the message is nonsensical because it fails to realize that self is the specialest of special cases in terms of method signature parsing.