More templated type argument inference

[bearophile]

Timon Gehr:

> I think we want to support things like:
>
> [1,2,3].map(a=>2*a);

This was one of my original use cases.


> It may be argued that this is too complex. :o)

Even if they are trying to speed up Scala compilation, it's much 
slower than Java/D compilation, because the Scala type system is 
very complex and refined and the compiler has to work a lot.
If the D type system gets refined as we are discussing here, 
maybe the compilation speed of templates will be reduced a 
little. I have no idea if this is true, and how much.

Bye,
bearophile