try {
  eval("to_string(5) = \"some string\"")
  assert_true(false)
} catch (e) {
  print("Caught Error: " + e.what());
}



try {
  eval("var v = [1,2,3]; v.size() = 3")
  assert_true(false)
} catch (e) {
  print("Caught Error: " + e.what());
}