[Bug libstdc++/94033] [10 Regression] is_trivially_copy_constructible<> fails with compiler error on complicated object with private default constructor

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94033

--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I have a fix for master, I'm just trying to figure out why we aren't seeing
this on the gcc-9 branch too.