Why is this an issue?

A case statement contains more than one item with the same value. Case items are evaluated and selected in order and so the second one will never be matched.

How to fix it

Code examples

Noncompliant code example

module fly;
  int i;
  initial begin
    case (i)
      1, 2:;
      3, 1:;
      default;
    endcase
  end
endmodule

Compliant solution

module fly;
  int i;
  initial begin
    case (i)
      1, 2:;
      3:;
      default;
    endcase
  end
endmodule