Add support implicit conversion between types

[ilya-stromberg]

On Friday, 6 September 2013 at 13:39:20 UTC, deadalnix wrote:
> You don't want a keyword for that. Something obscure and ugly 
> is required.

C# have operator overloading for this.

We can use, for example, "opImplicitRightCast"

struct Foo
{
    Foo opImplicitRightCast(T)(T from);
}