Disappointing inflexibility of argument passing in D

[Andrea Fontana]

On Tuesday, 11 February 2014 at 15:10:57 UTC, Carl Sturtivant 
wrote:
>
> D has opAssign, making defining implicit conversions from any 
> type to a new type possible on assignment, so where is the 
> analogue (say opPass) for passing an argument to a function?
>
> void f( Data d, Data2 d2) { ..... }
>
> void main() {
>        //conversions from string part of the definitions of 
> Data, Data2
>     f( "hello", "bonjour"); //no way to do this --- 
> disappointing
> }
>
> See
> http://forum.dlang.org/thread/agstjpezerwlgdhphclk@forum.dlang.org

In the meanwhile maybe you can try a workaround with templates? 
Something like:

void f(D1, D2)(D1 d, D2 d2) if (is(D1:Data) && is(D2 : Data2))
{
    // Temp vars and assignment
    ...
    ...
    f(tmpD1, tmpD2);
}