Something

parse errors:
  new Foo()->bar();
  (new Foo())->bar();
valid:
  id(new Foo())->bar();
definition:
  function id($foo) { return $foo; }

parse error:
  foo()[$bar];
valid:
  fn_idx(foo(), $bar);
definition:
  function fn_idx($foo, $bar) { $foo[$bar]; }