On 8/13/2012 12:46 AM, John Maddock wrote:
Right. It can be easily turned into a compile-time error by static_assert'ing that the function's return type is not sfinae_error, but the compiler error wouldn't be informative. You'd have to run to code to see the error.
I was hoping to have a way to transport the error to an API boundary and reporting it there, instead of presenting users with an imposing template instantiation backtrace, but that might not be possible.
I haven't followed this discussion, but you can move static_assert's up the call stack by moving the condition into an enable/disable_if, then the compiler simply doesn't find the function and you get the error "sooner".
But you've probably considered all this already yours, John.
John, what you're describing is precisely what we're trying to avoid: a mysterious "cannot find function" error because the function has been SFINAE'd out ... but where and why? The programmer needs better feedback than that. -- Eric Niebler BoostPro Computing http://www.boostpro.com