------- Additional Comments From gdr at cs dot tamu dot edu 2004-10-12 09:55 ------- Subject: Re: [3.4/4.0 regression] local classes as template argument
"mmitchel at gcc dot gnu dot org" <[EMAIL PROTECTED]> writes: | The bug here is that we are checking complain at all. | | SFINAE does not say that when given a set of overload candidates you perform | type deduction and then discard any candiates for which an any error occurs. | Instead, you perform type deduction and discard any candidates for which type | deduction fails, which is a defined term in [temp.deduct]. Type | deduction fails only under precise circumstances; using a local | class as a template argument is not a case in which type deduction fails. Absolutely. | It looks like people have been throwing around "complain & tf_error" | checks too freely in pt.c. Amen. | The question is then what happens after type deduction succeeds. | Should we emit an error before doing overload resolution, or only if | the invalid function is selected from the overload set? DR 415 is a | related issue and the proposed resolution suggests that errors about | invalid substitutions may be issued before overload resolution. My inclination is to emit the error only if the invalid function is selected from the overload set. I can see where DR 415 is heading, and I think its general concern will no doubt be discussed in Redmond or following as it affects large part of C++ evolution. In the mean time, I would recommend we emit the error only if the invalid function is selected. -- Gaby -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17413
