Escaped Mutant for Mutator "PublicVisibility": --- Original +++ New @@ @@ /** * Find one element that starts with #[ and ends with ] and the attributes inside. */ - public static function collectOne(Tokens $tokens, int $index) : AttributeAnalysis + protected static function collectOne(Tokens $tokens, int $index) : AttributeAnalysis { if (!$tokens[$index]->isGivenKind(T_ATTRIBUTE)) { throw new \InvalidArgumentException('Given index must point to an attribute.');