Because I use a lot of self:: for constants, change phpmd code to accept self:: and parent::.
In the program PHP/PMD/Rule/CleanCode/StaticAccess.php at line 36, change to:
if ($this->isReferenceInParameter($reference)
|| $reference->getImage() === 'self'
|| $reference->getImage() === 'parent'
) {
continue;
}