[phobos] Exception chaining

[Jonathan M Davis]

On Wednesday 12 January 2011 00:10:59 Don Clugston wrote:
> * It is still possible to throw an Object which isn't derived from
> Throwable. Can we disallow this?

I don't understand why it was ever allowed. Permitting you to throw something 
not derived from a common exception class seems incredibly stupid. I hate the 
fact that C++ does it, and I was surprised when I learned that D propagated the 
mistake. And especially since we pretty much seem to act like everything which 
is thrown is derived from Throwable, I don't see why it isn't actually the case. 
The Throwable, Exception, Error hierarchy makes sense. Allowing someone to throw 
ints or strings or whatnot doesn't.

- Jonathan M Davis