It's not quite half the bugs on GCCs bug tracker, but it's very high: https://gcc.gnu.org/bugzilla/report.cgi?x_axis_field=&y_axis_field=resolution&z_axis_field

It's not quite half the bugs on GCCs bug tracker, but it's very high: https://gcc.gnu.org/bugzilla/report.cgi?x_axis_field=&y_axis_field=resolution&z_axis_field=&no_redirect=1&query_format=report-table&short_desc_type=allwordssubstr&short_desc=&bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=SUSPENDED&bug_status=WAITING&bug_status=REOPENED&bug_status=RESOLVED&bug_status=VERIFIED&bug_status=CLOSED&cf_known_to_fail_type=allwords&cf_known_to_work_type=allwords&longdesc_type=allwordssubstr&longdesc=&bug_file_loc_type=allwordssubstr&bug_file_loc=&keywords_type=allwords&keywords=&cf_gcchost_type=allwordssubstr&cf_gcchost=&cf_gcctarget_type=allwordssubstr&cf_gcctarget=&cf_gccbuild_type=allwordssubstr&cf_gccbuild=&bug_id=&bug_id_type=anyexact&emailassigned_to1=1&emailtype1=substring&email1=&emailassigned_to2=1&emailreporter2=1&emailcc2=1&emailtype2=substring&email2=&emailtype3=substring&email3=&chfieldvalue=&chfieldfrom=&chfieldto=Now&j_top=AND&f1=noop&o1=noop&v1=&format=table&action=wrap https://gcc.gnu.org/bugzilla/report.cgi?x_axis_field=&y_axis... It's around 10% invalid bugs and another 10% duplicates. A lot of them that I've seen, including one of mine, are a result of misinterpreting details of language standards.