// @dart = 2.9
library test;

class A {
  int operator +(other) => 1;
  double operator -(other) => 2.0;
}

class B {
  A a;
}

var v_prefix_pp = (++new B().a);
var v_prefix_mm = (--new B().a);
var v_postfix_pp = (new B().a++);
var v_postfix_mm = (new B().a--);
main() {}