Rustc does not like this code.

1. The rust code

struct MyStruct {}

impl MyStruct {

    fn takes_mut_self(&mut self, _x:int) {}
    
    fn takes_self(&self) -> int { 42 }
    
    fn also_takes_mut_self(&mut self) {
        self.takes_mut_self(self.takes_self());
    }

}

fn main() {}

2. The error message from rustc

mut-self-issues.rs:12:28: 12:32 error: loan of dereference of mutable & pointer as immutable conflicts with prior loan
mut-self-issues.rs:12         self.takes_mut_self(self.takes_self());
                                                  ^~~~
mut-self-issues.rs:12:8: 12:12 note: prior loan as mutable granted here
mut-self-issues.rs:12         self.takes_mut_self(self.takes_self());
                                  ^~~~
error: aborting due to previous error