Red Hat tend to hide bug reports on their commercial (free software) compilers in bugzilla, unfortunately; I don't know what Adacore, for instance, or other com

Red Hat tend to hide bug reports on their commercial (free software) compilers in bugzilla, unfortunately; I don't know what Adacore, for instance, or other commercial providers do, and such bug reports will be only a small part of it. You could obviously study the defects in released versions of GCC on which commercialized versions are based, though, to the extent they have PRs. A great benefit of GCC was always enabling learning and research, though there are more opportunities these days.