Description

Category: Bug

A variable appears in the code only once. In many cases it may be the result of a mistake or a typo.

Example

$variable = 1;

for ($i=0; $i<10; $i++) {
    $variable += $i;
    if ($variale > 10) { // typo - should be $variable
        echo "impossible!";
    } else if ($var == 5) { // wrong variable name here - should be $variable
        echo "in the middle";
    }
}