56     protected $source;  variable in Antlr\\Antlr4\\Runtime\\CommonToken
94         ?Pair $source = null,  argument
99         if ($source !== null && !$source->a instanceof TokenSource) {
103         if ($source !== null && !$source->b instanceof CharStream) {
107         $this->source = $source ?? self::emptySource();
113         $tokenSource = $this->source->a;
127         static $source;
129         return $source = $source ?? new Pair(null, null);
145         $token = new self($this->type, $this->source, $this->channel, $this->start, $this->stop);
263         $source = $this->source->a;
265         if ($source !== null && !$source instanceof TokenSource) {
269         return $source;
274         $stream = $this->source->b;
285         return $this->source;