[Bug c++/92399] Rejects valid: reading of an inactive union member that shares common initial sequence with the active on

[nok.raven at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92399

Nikita Kniazev <nok.raven at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Nikita Kniazev <nok.raven at gmail dot com> ---
This has to be disallowed by [expr.const]/4.9​:

> An expression e is a core constant expression unless the evaluation of e, 
> following the rules of the abstract machine ([intro.execution]), would 
> evaluate one of the following:
> — ...
> — an lvalue-to-rvalue conversion that is applied to a glvalue that refers to 
> a non-active member of a union or a subobject thereof;
> — ...