Who knows? Technically, you can review the whole of these languages source code, but that doesn’t ensure anything. Tricks and backdoors can be hidden in plain sight VERY easily. Even if it’s safe now, it may not always be. If the future of your project is a concern, which it always should be, this should be a consideration.

Surveillance aside, Google giveth and Google taketh away. We can’t trust them not to fuck us over with some legal / licensing bullshit tomorrow.