[Bug c++/90885] GCC should warn about 2^16 and 2^32 and 2^64

[yann at droneaud dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90885

--- Comment #7 from Yann Droneaud <yann at droneaud dot fr> ---
The issue was noted on twitter by John Regehr, in
https://twitter.com/johnregehr/status/1139295920997068800 and following
messages.

The warning was suggest again by John Regehr in
https://twitter.com/johnregehr/status/1139302389612077056