Any statement (other than a null statement, which means a statement containing only a semicolon ;) which has no side effect and does not result in a change of control flow will normally indicate a programming error, and therefore should be refactored.

Noncompliant Code Example

$a == 1; // Noncompliant; was assignment intended?
$a < $b; // Noncompliant; have we forgotten to assign the result to a variable?
{code}

See