Missing pow implementation for integers

[flaper87]

$ cat test.rs                                                                                                                                                                                   101 ↵  
fn main() {
    2.pow(3);
}
$ rustc test.rs                                                                                                                                                                                        
test.rs:2:5: 2:14 error: type `<VI0>` does not implement any method in scope named `pow`
test.rs:2     2.pow(3);
              ^~~~~~~~~
error: aborting due to previous error
task 'rustc' failed at 'explicit failure', /home/flaper87/workspace/personal/rust/src/libsyntax/diagnostic.rs:75
task '<main>' failed at 'explicit failure', /home/flaper87/workspace/personal/rust/src/librustc/lib.rs:453

[adrientetar]

Upon investigation, this is the relevant method:
http://static.rust-lang.org/doc/master/std/num/trait.Real.html#tymethod.pow

Real numbers must implement Signed + Orderable + Round + Div, yet ints aren't considered real numbers because they don't implement Round (only float types do as of now).
http://static.rust-lang.org/doc/master/std/num/trait.Round.html

[flaper87]

Yeah, @bjz is doing some work on cleaning the num package. As for this bug, we can either wait for that work to be complete or implement pow as part of the Integer trait.

There are some methods in the Real trait that we can't implement for Int or at least are not worth it. For example: http://static.rust-lang.org/doc/master/std/num/trait.Real.html#tymethod.pi

I'm already working on an implementation of pow for the Integer trait. This covers Int, Uint, BigInt and BigUint

[adrientetar]

So, Real trait is designed as to exclude subsets it seems.