[Bug c++/102799] decltype with lambda without body error cause ICE

[nickhuang99 at hotmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102799

--- Comment #1 from qingzhe huang <nickhuang99 at hotmail dot com> ---
Forget to mention that obviously this only happens with "-std=c++20" because of
lambda in unevaluated context support.