Why is this an issue?

An issue is raised when multiple clocks are used within the same process.

How to fix it

Code examples

Noncompliant code example

process (clk1, clk2) is -- Noncompliant: Two clocks
begin
  if rising_edge(clk1) then
    s <= not s;
  end if;
  if rising_edge(clk2) then
    s <= s;
  end if;
end process;

Compliant solution

process (clk) is -- Compliant: One single clock
begin
  if rising_edge(clk) then
    s <= not s;
  end if;
end process;