array(2) {
  [0]=>
  array(4) {
    ["file"]=>
    string(%d) "%Sdebug_backtrace_trait_helper.inc"
    ["line"]=>
    int(15)
    ["function"]=>
    string(15) "print_backtrace"
    ["args"]=>
    array(0) {
    }
  }
  [1]=>
  array(7) {
    ["file"]=>
    string(%d) "%Sdebug_backtrace_trait.php"
    ["line"]=>
    int(7)
    ["function"]=>
    string(3) "bar"
    ["class"]=>
    string(1) "C"
    ["object"]=>
    object(C)#1 (0) {
    }
    ["type"]=>
    string(2) "->"
    ["args"]=>
    array(1) {
      [0]=>
      object(stdClass)#2 (0) {
      }
    }
  }
}
HipHop Fatal error: Argument 1 passed to C::bar() must be an instance of stdClass, int given in %Sdebug_backtrace_trait_helper.inc on line 16