Proposed resolution:

This wording is relative to N4606.

1. Change [global.functions] p4:

   Unless otherwise specified, calls made by functions in the standard library to non-operator, non-member functions in the standard library shalldo not use functions from another namespace which are found through argument-dependent name lookup (3.4.2). [Note: The phrase "unless otherwise specified" applies to cases such as the swappable with requirements ([swappable.requirements]). The exception for overloaded operators allowsis intended to allow argument-dependent lookup in cases like that of ostream_iterator::operator= (24.6.2.2):

   Effects:

   *out_stream << value;
   if (delim != 0)
     *out_stream << delim ;
   return *this;
   

   — end note]