anchor.diff:  
   var r1 = (i, name: pi, s);
   
  -Record foo() {
  +(int, double, String) foo() {
     int x = 0;
     return (x++, 1.1 + x, s);
   }
   
   class A {
  -  Record ar;
  +  (num, {String name}) ar;
     A(this.ar);
   }
   
  
positive.code:   static final sr = (ci, C.ci, i);
  
    int cx = 1;
    Record cr;
  
    C(this.cr): super((i, name: "answer"));
    C.c1(): cr = (s: s), super((pi, name: "pi"));
  
    Record m() {
      int _x0 = 1;
      return (s: cx, sr, ++_x0);
    }
  
    Record get g => (cx, x: cr);
  }
  
  main() {
  
negative.code:   Expect.equals(0, foo().$0);
    Expect.equals(2.1, foo().$1);
    Expect.equals(s, foo().$2);
    Expect.equals(-1, c1.cr.$0);
    Expect.equals(s, c1.cr.s);
    Expect.equals(i, c.cr.$0);
    Expect.equals(s, c.cr.s);
  