[Bug c++/126643] [contracts] ICE on implicit conversion inside template function precondition

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126643

--- Comment #1 from keng <kengusername at proton dot me> ---
The ICE also happens when accessing a struct member

```
struct num {
    signed x;
};
template<auto = 0> constexpr auto foo(num x) pre(x.x > 1) {}
static_assert((foo({123}), 0));
```

https://godbolt.org/z/d7eabfe59