text: Non-simple variables are forbidden in PHP 7
  -----
  <?php
  global $$foo->bar;
  -----
  !!php7
  Syntax error, unexpected T_OBJECT_OPERATOR, expecting ';' from 2:13 to 2:14
  array(
      0: Stmt_Global(
          vars: array(
              0: Expr_Variable(
                  name: Expr_Variable(
                      name: foo
                  )
              )
          )
      )
      1: Expr_ConstFetch(
          name: Name(
              parts: array(
                  0: bar
              )
          )
      )
  )