Operator dispatch: T op 1.0 works, but 1.0 op T doesn't

[japaric]

STR

Given the proper (commutative) Add/Mul implementations. (See this playpen link)

const I: Complex<f32> = Complex { re: 0., im: 1. };

let z = I * 3.;  // OK
let z = I + 3.;  // OK
let z = 3. * I;  // Err
let z = 3. + I;  // Err

Output

error: mismatched types: expected `_`, found `Complex<f32>` (expected floating-point variable, found struct Complex)

@nikomatsakis Could this work in the future? It would be great if could type 3. + 4. * I instead of I * 4. + 3., the former feels more natural.

[nikomatsakis]

Hmm. Yeah, I think we can make this work without too much difficulty, I kind of didn't realize it wouldn't work already, but I can see why it doesn't. It's (I believe) specific to the builtin types like int/float/etc.

[japaric]

@nikomatsakis awesome!