/**
* @param string[] $variableTypes indexed by variable name
*
* @return bool
*/
public function canCauseSideEffects(array $variableTypes) : bool
{
if (self::GLOBAL_VAR === $this->variable->name) {
return true;
}
$lastOperation = $this->getLastOperation();
// @todo any of the following operations on array sub-keys is also to be banished, so we need to consider
// any operation on any array key as on "mixed" and re-run this check.
if (null === $lastOperation) {
return false;
}
$isScalar = $this->isScalarType($variableTypes);
if ($lastOperation instanceof Node\Expr\Cast\String_ && !$isScalar) {
return true;
}
if ($lastOperation instanceof Node\Expr\Cast) {
return false;
}
if ($lastOperation instanceof Node\Expr\Cast\String_ && $isScalar) {
return false;
}
if ($lastOperation instanceof Node\Expr\ArrayDimFetch && $isScalar) {
// checking parent operation, since we can't have any assumptions on any of the types
// of the array keys, we have to check the operations applied to that array key for side-effects
$parentCheck = new self(new Variable(uniqid('surrogateVariableNameForTheArrayDimFetch', true)), array_slice($this->parentOperations, 0, count($this->parentOperations) - 1));
return $parentCheck->canCauseSideEffects($variableTypes);
}
if (($lastOperation instanceof Node\Expr\BinaryOp\Concat || $lastOperation instanceof Node\Expr\AssignOp\Concat) && !$isScalar) {
return true;
}
if ($lastOperation instanceof Node\Expr\BinaryOp || $lastOperation instanceof Node\Expr\AssignOp) {
return false;
}
return !($lastOperation instanceof Return_ || $lastOperation instanceof Node\Expr\Assign);
}
