The use of operators pairs ( =+, =- or =! ) where the reversed, single operator was meant (+=,
-= or !=) will compile and run, but not produce the expected results.
This rule raises an issue when =+, =-, or =! is used without any spacing between the two operators and when
there is at least one whitespace character after.
Noncompliant Code Example
$target = -5;
$num = 3;
$target =- $num; // Noncompliant; target = -3. Is that really what's meant?
$target =+ $num; // Noncompliant; target = 3
Compliant Solution
$target = -5;
$num = 3;
$target = -$num; // Compliant; intent to assign inverse value of num is clear
$target += $num;
