https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101287
--- Comment #3 from Eligor Kadaf <eligorkadaf at gmail dot com> --- I had found this example during the investigation of one another exmaple from real life, which was the bug in clang, and as fas as it is marked as error in standard I had decided it must be compile time error. However, during further investigation of current example I have found it is an ill-formed; no diagnostics required, so I will close this report.
