Issues with unordered_map and unordered_multimap

[Pavel P]

Hi,

I noticed that unordered_map with g++ (4.7 or 5.2) cannot be used with
forward declared types:

#include <unordered_map>

class test;
typedef std::unordered_map<int, test> test_map;
typedef test_map::iterator test_map_iterator;  // <== error

here's error output: https://ideone.com/sy05RG

This same code works with std::map: https://ideone.com/poufNk
As far as I understand standard doesn't require that it would work,
still I think it would be nice that it worked similar to std::map. It
works ok with MSVC by the way.


The other issue is with unordered_multimap. Not sure what's going on
behind the scenes, but it was exceptionally slow in my case, and
unorderedmap::operator[] was taking like 80% of CPU in my app. I ended
up replacing it with unordered_map<lkey, list<value> > to solve it.

Any ideas?.

Thanks,
Pavel