[Bug libstdc++/53339] unordered_map::iterator requires Value to be complete type

[eltoder at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53339

Eugene Toder <eltoder at gmail dot com> changed:

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--- Comment #12 from Eugene Toder <eltoder at gmail dot com> 2012-05-15 04:05:22 UTC ---
Created attachment 27408
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27408
Remove _Select1st hard-coding

This works for me. Although it's a bit annoying that _Select1st is hard coded
in quite a few places. What do you think of this change (on top of your latest
patch) to rely on std::pair instead of __detail::_Select1st in template
specialization? It seems it's closer to what the comment says:

   *  If the hashtable has a value type of the form pair<T1, T2> and a
   *  key extraction policy (_ExtractKey) that returns the first part
   *  of the pair, the hashtable gets a mapped_type typedef.