Hello

I have some difficulties to implement a trait.

I have define a trait Tensor and I do not manage to implement the Add trait. I get the error E0207.

Does somebody has any idea how to solve this problem?

```
use std::collections::*;
use std::hash::*;
use std::ops::Add;
type Int = i32;
type Real = f64;
type Size = usize;
trait Tensor<K, V> {
fn size(&self) -> Size;
fn apply(&self, k :K) -> V;
fn update(&mut self, k :K, v :V);
}
impl <V2, V1 :Add<V2>, C :Tensor<Size, V1>> Add<V2> for C {
type Output = C;
fn add(self, rhs: V2) -> C {
self.apply(0) + rhs;
println!("add");
self
}
}
```

The error message is

Thanks

Sebastien