In reply to Reuben:
Don’t put
this. in front of the function when using it as a return value.
virtual function data_error chk_data_error (bit [8:0] data_bit_err[]);
chk_data_error = new[data_bit_err.size];
foreach(data_bit_err[i])
chk_data_error[i] = |data_bit_err[i];
endfunction : chk_data_error