[Bug c++/78890] [5/6/7 Regression] ICE on invalid reference type in union

[rs2740 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78890

TC <rs2740 at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |rs2740 at gmail dot com

--- Comment #3 from TC <rs2740 at gmail dot com> ---
[class.union]/3 in the current WP (/2 in N3337/N4140) says (among other
things):

If a union contains a non-static data member of reference type the program is
ill-formed.