For the code below ```c++ union U { struct {} s; }; ``` [cppinsigths produces](https://cppinsights.io/lnk?code=dW5pb24gVSB7CiAgc3RydWN0IHt9IHM7Cn07&insightsOptions=cpp17&std=cpp17&rev=1.0) ```c++ struct U { struct { }; struct (anonymous) s; }; ```