to!() conversion between objects

[Piotr Szturmaj]

I have written a simple conversion template for tuples, structs and classes:

https://gist.github.com/1299046

The problem is that it may conflict with to!Class1(Class2) template. 
This template does dynamic cast and throw exception when the target is 
null and source is non null. Why implement that in std.conv? Why not 
enforce(cast(Class1)Class2_object) or maybe create something like 
DynamicCast!T?

Currently, in my private repo I added a constraint so dynamic cast 
template is chosen only if tupleof lengths are different. If they are 
the same then conversion is performed on each field, but I think it may 
be sometimes ambiguous.

Is that field-by-field conversion welcome in Phobos at all?

Thanks