Optional chaining gotchas
Optional chaining != error suppression operator.
(function () {
'use strict';
undeclared_var?.b; // ReferenceError: undeclared_var is not defined
arguments?.callee; // TypeError: 'callee' may not be accessed in strict mode
arguments.callee?.(); // TypeError: 'callee' may not be accessed in strict mode
true?.(); // TypeError: true is not a function
})();