https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115285
--- Comment #16 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to frs.dumont from comment #15) > It's surprising that we need to handle this use case. The user wants K > is to be explicitly built from int but then insert ints, weird. How else would you insert a range of values constructed from the ints into the container? The user can insert them one-by-one like this: for (auto i : int_range) m.emplace(i); So there's no reason to prevent them from doing it using insert(first, last). > Are other Standard library handling this ? Yes, because the standard requires it. The requirement on insert(i, j) is "value_type is Cpp17EmplaceConstructible into X from *i", which means that allocator_traits<A>::construct(m, p, *i) must be valid. allocator_traits::construct always does explicit construction of a new object, there is no implicit conversion. This means that insert(i, j) must be equivalent to emplace(*i) in a loop. Which is what my patch does.
