Why is this an issue?

Signals and variables should not be assigned in multiple processes or equivalent concurrent assignments.

How to fix it

Code examples

Noncompliant code example

architecture a of e is
begin
  f <= not ((a and b) or c);
  with a select f <= '0' when '0', '1' when others;
end;

Compliant solution

architecture a of e is
begin
  f <= not ((a and b) or c);
  with a select g <= '0' when '0', '1' when others;
end;