Hello, > > > Jeffrey A Law wrote: > > > > Another possibility is to simply not allow conversions between a > > > > subtype and basetype. > > > > > > Such a patch also solves the problem. But I'm not sure to understand > > > the impact on other codes. Is this kind of conversion between a type > > > and its basetype specific to Ada? > > > > this still seems unnecessarily conservative to me. I would just check > > for types whose TYPE_MIN and TYPE_MAX do not match the natural values > > derived from the type precision (i.e., those returned by > > upper_bound_in_type (type, type) and lower_bound_in_type (type, type)). > I doubt it matters in any significant way -- your proposed solution > may allow optimization in a few more cases of Ada code, but at a > compile-time cost (probably not significant).
just forbidding cast to a subtype does not seem enough -- cast from any type to the type in that TYPE_MIN and MAX do not match TYPE_PRECISION may cause problems. I am not sure whether such casts really appear, but I do not see any principial reason why they should not. Zdenek
