https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99331
--- Comment #3 from Nikita Kniazev <nok.raven at gmail dot com> ---
This one most likely has the same root problem:
template <int N> struct X {};
template <typename T>
struct foo { using t = X<sizeof(T)>; };
<source>:3:26: error: conversion from 'long unsigned int' to 'int' may change
value [-Werror=conversion]
3 | struct foo { using t = X<sizeof(T)>; };
| ^~~~~~~~~
