[Bug c++/122269] Error on constexpr structured binding using tuple protocol

[tkaminsk at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122269

--- Comment #1 from Tomasz Kamiński <tkaminsk at gcc dot gnu.org> ---
Adding static to structured binding declarations make the code compile. 

However, I believe that with contexpr references to unknown,  each
call`<unnamed>.get<I>()` should be constant expression, as `get<I>()` is
static, so `<unnamed>` is not used.