[Bug libstdc++/51365] cannot use final empty class in std::tuple

marc.glisse at normalesup dot org gcc-bugzilla@gcc.gnu.org
Sun Dec 11 13:56:00 GMT 2011


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51365

--- Comment #11 from Marc Glisse <marc.glisse at normalesup dot org> 2011-12-11 13:51:20 UTC ---
(In reply to comment #10)
> I haven't really thought about it either, but one advantage of depending on
> is_empty is that it prevents using the EBO for polymorphic classes, where
> derivation could have undesirable effects.

Ah, right, the set of types that can safely be derived from is rather
restricted: non-builtin, non-final, non-virtual (and possibly more
constraints). And to benefit from additional packing: non-C++03-POD. Probably
not worth the trouble...



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