PHP’s "variable variables" feature (dynamically-named variables) is temptingly powerful, but can lead to unmaintainable code.
Noncompliant Code Example
$var = 'foo';
$$var = 'bar'; //Noncompliant
$$$var = 'hello'; //Noncompliant
echo $foo; //will display 'bar'
echo $bar; //will display 'hello'
