https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103039
--- Comment #1 from martin <mscfd at gmx dot net> --- The warning which is shown during compilation is: seltype.f90:16:59: 16 | !$omp parallel do default(shared) private(k) reduction(+:s) | ^ Warning: ‘__tmp_class_a’ is used uninitialized [-Wuninitialized] seltype.f90:15:12: 15 | class is (a) | ^ note: ‘__tmp_class_a’ declared here