The each_char method on &str doesn't work because multiple applicable methods are in scope

[Thiez]

The following program

fn main() {
    do "somestr".each_char |_| { false }
}

Gives this error:

treegrep.rs:2:39: 2:40 error: multiple applicable methods in scope
treegrep.rs:2     do "somestr".each_char |_| { false }
                                                     ^
treegrep.rs:2:39: 2:40 note: candidate #1 is `core::io::__extensions__::each_char`
treegrep.rs:2     do "somestr".each_char |_| { false }
                                                     ^
treegrep.rs:2:39: 2:40 note: candidate #2 is `core::str::__extensions__::each_char`
treegrep.rs:2     do "somestr".each_char |_| { false }
                                                     ^
treegrep.rs:2:39: 2:40 error: failed to find an implementation of trait core::io::Reader for &'static str
treegrep.rs:2     do "somestr".each_char |_| { false }
                                                     ^

It seems this significantly reduces the utility of each_char. Interestingly the last error (failed to find an implementation...) only shows up about half the time.
I'm not entirely sure how &str implements ReaderUtil.

[Dretch]

This is the same bug as #5664.

[Thiez]

So it is.