Sorry, missed this yesterday. From the spec: “A new multidimensional array of the array type is allocated from the garbage-collected heap. If any count value i

Sorry, missed this yesterday. From the spec: “A new multidimensional array of the array type is allocated from the garbage-collected heap. If any count value is zero, no subsequent dimensions are allocated. The components of the array in the first dimension are initialized to subarrays of the type of the second dimension, and so on. The components of the last allocated dimension of the array are initialized to the default initial value (§2.3, §2.4) for the element type of the array type. A reference arrayref to the new array is pushed onto the operand stack.” It’s really a little utility method that happens to be pushed all the way to the byte code for historical reasons. The arrays it produces aren’t multidimensional in the ways you might hope, they are just arrays of arrays, which remain mutable and so can become ragged, or be reassigned in sneaky or horrible ways (e.g. with a subtyped array). There has been lots of talk over the years about how we could do better, often motivated by projects like Panama which are concerned with interfacing with other languages which do have firmer concepts of multidimensional arrays, but these are generally at a slightly higher level and try to avoid messing with lower level things the VM has to know about.