[Bug c++/110836] [C++20] g++ should report when there is no way to create structure or class

[andris at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110836

--- Comment #2 from Andris Pavenis <andris at gcc dot gnu.org> ---
Warning would allow to detected problem earlier.

Otherwise it could only be detected later in case when affected structure or
class is part of an library and its objects are not created directly inside the
library. In this case the inability to create objects may only be detected
later when building other packages which uses this library

In our case the problem appeared when replacing deriving from
boost::noncopyable with added deleted copy constructor and deleted assignment
operators.