Why is this an issue?

To improve readability, useless true and false keywords should be removed.

How to fix it

Code examples

Noncompliant code example

if a = true then -- Noncompliant
  ...
end if;

if b = false then -- Noncompliant
  ...
end if;

if c /= true then -- Noncompliant
  ...
end if;

if d and true then -- Noncompliant
  ...
end if;

Compliant solution

With custom forbidden attribute list: val

if a then
  ...
end if;

if not b then
  ...
end if;

if not c then
  ...
end if;

if d then
  ...
end if;