[Bug libstdc++/53734] std::is_constructible fails to compile if copy constructor is private

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53734

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-06-20 
19:04:17 UTC ---
G++ doesn't yet implement access-checking during template deduction.