Why is this an issue?

All declared parameters should be used in the corresponding function/procedure. Useless parameters should be removed.

How to fix it

Code examples

Noncompliant code example

function f(
  arg1 : std_logic,
  arg2 : std_logic -- Noncompliant: "arg2" is not used
) return std_logic is
begin
  return arg1;
end;

Compliant solution

function f(
  arg1 : std_logic,
  arg2 : std_logic
) return std_logic is
begin
  return arg1 or arg2;
end;