https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87822
--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> --- Author: redi Date: Wed Oct 31 13:03:25 2018 New Revision: 265681 URL: https://gcc.gnu.org/viewcvs?rev=265681&root=gcc&view=rev Log: PR libstdc++/87822 fix layout change for nested std::pair The introduction of the empty __pair_base base class for PR 86751 changed the layout of std::pair<std::pair<...>, ...>. The outer pair and its first member both have a base class of the same type, which cannot exist at the same address. This causes the first member to be at a non-zero offset. The solution is to make the base class depend on the template parameters, so that each pair type has a different base class type, which allows the base classes of the outer pair and its first member to have the same address. PR libstdc++/87822 * include/bits/stl_pair.h (__pair_base): Change to class template. (pair): Make base class type depend on template parameters. * testsuite/20_util/pair/87822.cc: New test. Added: branches/gcc-8-branch/libstdc++-v3/testsuite/20_util/pair/87822.cc Modified: branches/gcc-8-branch/libstdc++-v3/ChangeLog branches/gcc-8-branch/libstdc++-v3/include/bits/stl_pair.h
