https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94623
--- Comment #4 from David Binderman <dcb314 at hotmail dot com> --- Configure flags: ../trunk.git/configure --prefix=/home/dcb/gcc/results.20200416 \ --disable-bootstrap \ --disable-multilib \ --disable-werror \ --enable-checking=df,extra,fold,rtl,yes \ --enable-languages=ada,c,c++,d,fortran,go sed 's/-O2/-O3 -march=native/' < Makefile > Makefile.tmp mv Makefile.tmp Makefile Host gcc version is 9.3.1 and glibc version is 2.30 on fedora x86_64. The line that ices is the following: assert((*collateral->value->elements)[5]->type->ty == Tclass); Hopefully that is enough information to be able to attempt to reproduce the problem.