https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90998
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-8 branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:f52ec6bc163af837cd13e234b7c2eab6bc456e12 commit r8-10081-gf52ec6bc163af837cd13e234b7c2eab6bc456e12 Author: Marek Polacek <pola...@redhat.com> Date: Wed Feb 26 00:33:52 2020 -0500 PR c++/90998 - ICE with copy elision in init by ctor and -Wconversion. After r269667 which introduced joust_maybe_elide_copy, in C++17 we can elide a constructor if it uses a conversion function that returns a prvalue, and use the conversion function in its stead. This eliding means that if we have a candidate that previously didn't have ->second_conv, it can have it after the elision. This confused the -Wconversion warning because it was assuming that if cand1->second_conv is non-null, so is cand2->second_conv. Here cand1->second_conv was non-null but cand2->second_conv remained null, so it crashed in compare_ics. I checked with clang that both compilers call A::operator B() in C++17 and B::B(A const &) otherwise. gcc/cp/ChangeLog 2020-02-26 Marek Polacek <pola...@redhat.com> PR c++/90998 - ICE with copy elision in init by ctor and -Wconversion. * call.c (joust): Don't attempt to warn if ->second_conv is null. gcc/testsuite/ChangeLog 2020-02-26 Marek Polacek <pola...@redhat.com> PR c++/90998 - ICE with copy elision in init by ctor and -Wconversion. * g++.dg/cpp0x/overload-conv-4.C: New test.
