On Fri, Jul 6, 2012 at 1:23 PM, Eric Niebler <eric@boostpro.com> wrote:
On 7/6/2012 12:54 PM, Marc Glisse wrote:
On Fri, 6 Jul 2012, Eric Niebler wrote:
The end result is that the user is presented with an error like: "no viable function A, template substitution failed." The user is given no information about which function in the chain failed to compile, or why. This is a serious usability problem!
... in your compiler.
All suggestions welcome,
Use g++. <snip informative backtrace>
Ah! Thanks. I'm using clang. I agree, it's a compiler QoI issue. I'll follow up with them.
FWIW, top-of-tree Clang produces: t.cpp:12:3: error: no matching function for call to 'f' f(0); ^ t.cpp:8:8: note: candidate template ignored: substitution failure [with T = int]: no matching function for call to 'g' auto f(T x) -> decltype(g(x)) { return g(x); }; ^ ~ Which could probably still be improved, although I can't convince myself that GCC 4.8 is doing us favors by producing the complete SFINAE backtrace. - Doug