Array as an argument, ambiguous behaviour.

[Cooler]

> It's not unpredictable, at least not more unpredictable then 
> fun2.
>
> Should we dissallow this two?
>
> int[] a = [1,2,3,4];
> b = a;
> b ~= [5, 6, 7, 8];

You don't understand me. You consider that I am author of the 
fun() and the caller side.
Read two post above 
http://forum.dlang.org/post/dxqxlhyhmdfuashhmtrz@forum.dlang.org

I consider that author of fun() and author of caller side are 
different persons. They must agree between them how to provide 
some functionality.
If I fun()'s author why do I need to provide fun3() if I already 
provided fun1() and fun2()?
I I caller's author - why may I require fun3() variant, if I 
already have fun1() and fun2()?