Remove literal boolean values from conditional expressions to improve readability. Anything that can be tested for equality with a boolean value must itself be a boolean value, and boolean values can be tested atomically.

Noncompliant Code Example

if ($booleanVariable == true) { /* ... */ }
if ($booleanVariable != true) { /* ... */ }
if ($booleanVariable || false) { /* ... */ }
doSomething(!false);

$booleanVariable = condition ? true : exp;
$booleanVariable = condition ? false : exp;
$booleanVariable = condition ?  exp : true;
$booleanVariable = condition ?  exp : false;

Compliant Solution

if ($booleanVariable) { /* ... */ }
if (!$booleanVariable) { /* ... */ }
if ($booleanVariable) { /* ... */ }
doSomething(true);

$booleanVariable = condition || exp;
$booleanVariable = !condition && exp;
$booleanVariable = !condition ||  exp;
$booleanVariable = condition && exp;

Exceptions

The use of literal booleans in comparisons which use identity operators (=== and !==) are ignored.