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

[Mark Mitchell <mark at codesourcery dot com>]

Chris Lattner wrote:
> > Age-old debate: better to warn early about possibly broken interfaces, 
> > or late about definitely broken usage?  I think that warning early, 
> > together with what DJ is calling fine-grained warning control is the 
> > best solution.
>
>
> I don't agree at all on this.  It's not a matter of warning vs not 
> warning: it's a matter of emitting bogus warnings *sometimes* when you 
> can emit the proper warning *all of the time*.  Given a choice of an 
> accurate warning vs an warning that fires on a superset of the cases, 
> I'd prefer the former.  Warning "late" may just be a synonym for warning 
> only where there is a problem, as opposed to in every translation unit 
> that includes the header. :)

I understand where you're coming from.  The reason I said age-old debate 
is that we spent *weeks* worrying about this stuff for our 
error-checking tools at CenterLine, and talking to customers, and so 
forth and so on, and there was lots of passion on both sides.  There 
really isn't a right answer.

You're not looking at this from the perspective of a library developer 
who wants to check header files as they're being developed.

People actually make the same argument sometimes about things like:

void f() {
  int *p = 0;
  *p = 3;
}

saying "but I never call f, so I don't want a warning for it".

Languages like Python or LISP are the (extreme) logical extension of 
your point of view: just start running the program and if anything goes 
wrong, tell me about when it happens!

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304