In reply to suresh M:
Hi Suresh,
Here casez_option 3’b00? can match value of either 3’b000 or 3’b001.
While casez_option 3’b0?? can match values 3’b000,3’b001,3’b010,3’b011.
While priority keyword gives priority to first match.
i.e values 'b000 and 'b001 can be matched from either 3’b00? or 3’b0?? but because of priority first matched case_statement gets executed.
Values 4,5,6,7 are not getting satisfied with any of the provided casez_options so warning is generated !!