Trying to populate 2d array with struct. builds fine, error on run

[Sze]

You can instead allocate the 2d array on the heap:

Creating a big 2D array

I think the best solution would be to allocate the entire 2d array in one piece on the heap, instead of allocating them in parts. This is much simpler and should give you a better memory layout: const A: *[n][n]u64 = try allocator.create([n][n]u64); defer allocator.destroy(A);