As Ben’s example shows, the payload elements are randomized as well as the size of the array. There is no need to use the post_randomize() function.
Here is the relevant LRM section 18.4:
— Arrays can be declared rand or randc, in which case all of their member elements are treated as rand or randc.
— Individual array elements can be constrained, in which case the index expression may include iterative constraint loop variables, constants, and state variables.
— Dynamic arrays, associative arrays and queues can be declared rand or randc. All of the elements in the array are randomized, overwriting any previous data.