if m := errRE.FindStringSubmatch(line); m != nil {
			all := m[1]
			mm := errQuotesRE.FindAllStringSubmatch(all, -1)
			if len(mm) != 1 {
				t.Errorf("%s: invalid errorcheck line:\n%s", fileline, line)
			} else if err := errors[fileline]; err == "" {
				t.Errorf("%s: missing error, want %s", fileline, all)
			} else if !strings.Contains(err, mm[0][1]) {
				t.Errorf("%s: wrong error for %s:\n%s", fileline, all, err)
			}