What potential issue arises from using the assignment operator instead of the comparison operator in PHP?

Using the assignment operator (=) instead of the comparison operator (== or ===) in PHP can lead to unintended consequences, as it assigns a value to a variable rather than checking for equality. This can result in logical errors in your code. To solve this issue, always use the comparison operator when you want to check for equality between two values.

// Incorrect usage of assignment operator
$var = 10;

if($var = 5) {
    echo "This will always be executed";
}

// Correct usage of comparison operator
$var = 10;

if($var == 5) {
    echo "This will not be executed";
}