Using operator pairs (=+, =-, or =!) that look like reversed single operators (+=,
-= or !=) is confusing. They compile and run but do not produce the same result as their mirrored counterpart.
$target = -5;
$num = 3;
$target =- $num; // Noncompliant: target = -3. Is that the expected behavior?
$target =+ $num; // Noncompliant: target = 3
This rule raises an issue when =+, =-, or =! are used without any space between the operators and when there
is at least one whitespace after.
Replace the operators with a single one if that is the intention
$target = -5;
$num = 3;
$target -= $num; // target = -8
Or fix the spacing to avoid confusion
$target = -5;
$num = 3;
$target = -$num; // target = -3
