This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 112e. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
It would be useful to be able to deduce the type of a function template argument from a corresponding default function argument expression, for example:
template <class T> int f(T = 0); int x = f();
A more realistic use case would be
template <class T, class U> int f(T x, U y = pair<T, T>());
Ideally one would also like
template <class T, class U> int f(T x, U y = g(x));
These capabilities are part of the Boost parameter library, so there should not be issues of implementability.
Rationale (February, 2014):
EWG determined that no action should be taken on this issue.