ufuzz failure

[alexlamsl]

// original code
// (beautified)
var _calls_ = 10, a = 100, b = 10, c = 0;

const foo = b = a;

(c = c + 1) + (foo && foo[a++ + a--]);

console.log(null, a, b, c, Infinity, NaN, undefined);

// uglified code
// (beautified)
var n = 100;

n && n[n++ + n--], console.log(null, n, 10, 1, Infinity, NaN, undefined);

original result:
null 100 100 1 Infinity NaN undefined

uglified result:
null 100 10 1 Infinity NaN undefined

// reduced test case (output will differ)

// (beautified)
var a = 0, b = 1;

const foo = b = a;

1 && foo[a--];

console.log(a, b);
// output: -1 0
// 
// minify: -1 1
// 
// options: {
//   "ie8": true,
//   "toplevel": true,
//   "mangle": {
//     "v8": true
//   },
//   "output": {
//     "v8": true
//   },
//   "validate": true
// }

minify(options):
{
  "ie8": true,
  "toplevel": true,
  "mangle": {
    "v8": true
  },
  "output": {
    "v8": true
  }
}

Suspicious compress options:
  collapse_vars
  reduce_vars
  varify

Suspicious options:
  toplevel