[Bug c++/86429] [8/9 Regression] lambda capture breaks constexpr-ness

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86429

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The diagnostic should not mention the __closure name, as that's an
implementation details (see also PR 82643)