D should disallow forward references

[Robert Fraser]

grauzone wrote:
> I agree; but: I'm just saying that disallowing it would actually be 
> better for the programmer, than leaving it half-broken.

I strongly disagree. Dealing with header files, forward feference 
issues, etc. is the #1 reason I don't use C/C++ (really, I could live 
with the rest). D's forward reference errors are basically nonexistent 
within a single module, with the exception of templates, so it's not 
"half-broken" in any way.