[1] https://www.digitalmars.com/articles/C-biggest-mistake.html

float m[10][10];

it not a an array of pointers, but a 2D dimensional array with 2D memory layout.

    int[][] jagged; // an array of `int[]` (i.e. each element is a pointer to a `int[]`)
    int[,] multidimensional; // a "true" 2D array laid out in memory sequentially

    // allocate the jagged array; each `int[]` will be null until allocated separately
    jagged = new int[][10];
    Debug.Assert(jagged.All(elem => elem == null));
    for (int i = 0; i < 10; i++)
        jagged[i] = new double[10]; // allocate the internal arrays
    Debug.Assert(jagged[i][j] == 0);

    // allocate the multidimensional array; each `int` will be `default` which is 0
    // element [i,j] will be at offset `10*i + j`
    multiDimensional = new double[10, 10];
    Debug.Assert(multiDimensional[i, j] == 0);

  int N = 10;
  char buf[N] = { };
  auto x = &buf;

We simply can not name it without referring to N and we can also not use it in structs (ouch).

How is this not a quality of implementation issue? Any implementation is free to track all sizes as much as they want with the current standard.

Either a implementation is forced to issue an error at run time if there is an out of bounds read/write and in that case its a very different language than C, or its feature as-if lets any implementation ignore.

https://godbolt.org/z/qh7P93Tcd

And I agree that this is a misuse of auto. I only used it here to show that the type we miss already exists inside the C compiler, we simply can name it only by constructing it again:

char (buf)[N] = ...

but we could simply allow

char (buf)[:] =

and be done (as suggested by Dennis Richtie: https://www.bell-labs.com/usr/dmr/www/vararray.pdf)