https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100823
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:56c999860bbbb2fd5091ba0985e2e5eaa90c6478 commit r13-1770-g56c999860bbbb2fd5091ba0985e2e5eaa90c6478 Author: Jonathan Wakely <jwak...@redhat.com> Date: Wed Jul 20 16:51:44 2022 +0100 libstdc++: Fix std::common_iterator assignment [PR100823] This fixes the following conformance problems reported in the PR: - Move constructor and move assignment should be defined. - Copy assignment from a valueless object should be allowed. Assignment is completely rewritten by this patch, as the previous version had a number of problems. The converting assignment failed to handle the case of assigning a new value to a valueless object, which should work. It only accepted lvalue arguments, so wasn't usable to implement the move assignment operator. Finally, it enforced the precondition that the argument is not valueless, which is correct for the converting assignment but not for the copy assignment. A new _M_assign member is added to handle all cases of assignment (copying from an lvalue, moving from an rvalue, and converting from a different type). The not valueless precondition is checked in the converting assignment before calling _M_assign, so isn't enforced for copy and move assignment. The new function no longer uses a switch, so handles valueless objects as the LHS or RHS of the assignment. libstdc++-v3/ChangeLog: PR libstdc++/100823 * include/bits/stl_iterator.h (common_iterator): Define move constructor and move assignment operator. (common_iterator::_M_assign): New function implementing assignment. (common_iterator::operator=): Use _M_assign. (common_iterator::_S_valueless): New constant. * testsuite/24_iterators/common_iterator/100823.cc: New test.
