Use `std::array` or `stack_array` for arrays on the stack

Reason

They are readable and don't implicitly convert to pointers. They are not confused with non-standard extensions of built-in arrays.

Example, bad

const int n = 7;
int m = 9;

void f()
{
    int a1[n];
    int a2[m];   // error: not ISO C++
    // ...
}

Note

The definition of a1 is legal C++ and has always been. There is a lot of such code. It is error-prone, though, especially when the bound is non-local. Also, it is a "popular" source of errors (buffer overflow, pointers from array decay, etc.). The definition of a2 is C but not C++ and is considered a security risk.

Example

const int n = 7;
int m = 9;

void f()
{
    array<int, n> a1;
    stack_array<int> a2(m);
    // ...
}

Enforcement

• Flag arrays with non-constant bounds (C-style VLAs)
• Flag arrays with non-local constant bounds