Question w.r.t. `'class Foo' has virtual functions but non-virtualdestructor` warning.

[Chris Lattner]

Karel Gardas wrote:
> Yes, that's undefined, but I just define this class to be able to do:
> Foo* f = dynamic_cast<Foo*>(x);
> l = f->iiop_version();
> there is nothing like delete involved. Anyway, I agree with you that 
> emit warning about this is probably the right thing to do and so I will 
> fix my code.

I've run into this warning with C++ code as well, and it is quite 
annoying.  There are lots of possible reasons to want to do this sort of 
thing, and adding a virtual dtor increases the size of the vtable for the 
class.

It seems that the warning could be improved to be emitted when the 
*delete* is seen of a class without a virtual dtor (but that does have 
virtual methods).  If you never actually do the questionable behavior, 
you'd never get the warning.  It seems like a bug to emit it for the class 
definition.

-Chris

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