Abstract bug?

Main.hx

package ;

using Lambda;

class Main {

	public static function main() {
		var a = ['a', 'b', 'c'];
		var m:MyArray = a;
		
		if (m['a']) trace( m['a'] );
	}
	
}

abstract MyArray(Array<String>) from Array<String> to Array<String> {
	public function new(v:Array<String>) this = v;
	@:arrayAccess public function exists(v:String):Bool return this.indexOf(v) > -1;
	@:arrayAccess public function get(v:String):String return this[this.indexOf(v)];
}