[Bug c++/51336] [C++11] is_abstract and sfinae

[marc.glisse at normalesup dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51336

--- Comment #2 from Marc Glisse <marc.glisse at normalesup dot org> 2011-11-28 21:17:30 UTC ---
(In reply to comment #1)
> IMO you need one further indirection, e.g.

Ah, yes, makes sense (although clang accepts both versions).

> Btw.: Neither of these forms can ever prevent the "real" copy constructor to be
> declared, defined, and used by the compiler.

I was experimenting with it because I don't understand why this code (your
fixed version) is valid if that declaration has no effect... (well, it does
remove the implicit A(), but that doesn't count)

Maybe I should ask for a warning?