Re: [patch][C++] Enhancements to -Wconversion-null

[Jason Merrill <jason at redhat dot com>]

On 06/25/2010 07:29 PM, Le-Chun Wu wrote:
> +      if (arg == null_node
> +          && DECL_TEMPLATE_INFO (fn)
> +          && cand->template_decl
> +          && !(flags & LOOKUP_EXPLICIT_TMPL_ARGS))
> +        conversion_warning = false;

1) You don't need a new flag, you can just test cand->explicit_targs.

2) Testing for any explicit template arguments isn't really the right 
test: consider

template <class T> void f(T, int);

int main()
{
  f(1.0, NULL);
}

This call has no explicit template arguments, but it still passes NULL 
to a parameter that was not deduced from NULL.

3) Why do you want to suppress the warning in the deduced case, anyway? 
 Passing NULL to f(T) will still mean that we're calling f(uintptr_t) 
rather than f(some pointer), and is probably still wrong.

Jason