With the current c++20 standard the following code
#include <array>
struct S {
std::array<int, 4> arr;
void foo() {
static_assert(arr.size());
}
};
generate this error
main.cpp: In member function ‘void S::foo()’:
main.cpp:7:31: error: non-constant condition for static assertion
7 | static_assert(arr.size());
| ~~~~~~~~^~
main.cpp:7:31: error: use of ‘this’ in a constant expression
This would work if std::array::size would be static, also I don't think any old code would break for this change.
std::array::max_size and std::array::empty are similar and I think should be static.