Sneaky use of sequence points in c++

i've found a very interesting corner case where fiddly knowledge of
sequence points and STL are used.
apparently it's not possible to use remove_if on associate arrays but
this didn't stop me trying for a good 30 mins before i discovered this
workaround:

for(; iter != endIter; )
{
           if(Some Condition)
           {
                       // is it safe ?
                   aMap.erase(iter++);
           }
           else
           {
                   ++iter;
           }
}

There's no evidence in the answer, but it's apparent after digging
through the numerous overloads and associated nastiness that its
apparently excusable simplicity comes down to sneaky use of sequence
points.

http://www.cplusplus.com/reference/algorithm/remove_if/
http://stackoverflow.com/questions/800955/remove-if-equivalent-for-stdmap/800984#800984