Why is this an issue?

An empty port in a non-ANSI module/program/interface declaration is likely not intended and should be removed.

How to fix it

Code examples

Noncompliant code example

module fly(a,,b);
  input a;
  output b;
  ...
endmodule

Compliant solution

module fly(a, b);
  input a;
  output b;
  ...
endmodule