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Subject: Re: [boost] [type_traits] has_equal_to< std::vector<T> > alwaystrue_
From: John Maddock (boost.regex_at_[hidden])
Date: 2011-10-22 04:25:54


>Thanks for highlighting this major issue. I understand that there is
>nothing to do apart from specializing the traits for those particular
>std classes. This would however not work with user classes. As the
>beta is due on Monday, I believe it is too short to submit a working
>and tested patch. Maybe once the beta is out, you can start to work on
>a proposed contribution?
>Meanwhile, as suggested I will add a warning in the doc.

It's a tricky one, because strictly speaking vector<T> always does have an
equality operator - it's just that depending upon T it may not compile :-(

There's no general solution to this, because there's no way in the language
to test whether something does or does not compile - we can only test
whether it's declared or not.

John.


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