https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92542
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- The ICE started with r277865 "Implement C++20 operator<=>." aka g:b7689b962dd6536bbb2567bfdec52e35109af7ab It was fixed with r278786 "Implement P1814R0, CTAD for alias templates." aka g:1a291106384cabc73da0bc0f457b1cd3a4015970