[sv-bc] Struct/array assignment pattern

Hi,
In IEEE 1800 LRM, sec 8.13.1 specifies syntax/semantics of array assignment
patterns. Does it apply only on unpacked array, or packed unpacked both? All the
e.g. specified there used unpacked array. So I am bit confused. Is the following
e.g. valid?
typedef bit [2:0] bit_array;

                   module sample;
                   bit_array [3:0] a;

                   initial
                   a = { bit_array: {1, 1, 1}};

                   endmodule


Regards
Surya.