[Bug c++/50545] [C++0x] SFINAE does not handle an explicit type conversion (functional notation) with a braced-init-list well if target type is not dependent

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50545

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |SUSPENDED
   Last reconfirmed|                            |2011-10-13
                 CC|                            |jason at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #1 from Jason Merrill <jason at gcc dot gnu.org> 2011-10-13 22:02:12 UTC ---
int{ declval<T>() } is an example of an "instantiation-dependent" expression
that is neither type-dependent (its type is int) nor value-dependent (because
it's not a constant-expression), so G++ just resolves its decltype to int. 
This isn't what we want, but what exactly we do want is an open issue:

http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1172