ufuzz failure

[alexlamsl]

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

function f0() {
    function f1() {
        function f2(undefined_2, undefined_2_1, c) {
            function f3() {
            }
            var undefined_2_1 = f3((c = 1 + c, undefined_2_1 = (undefined_2_1 && (undefined_2_1.null = 5 % NaN <= "" / undefined)) / (-3 >= "foo" ^ -0 <= "undefined")));
            function f4(c) {
            }
            var b_1 = f4(false, "a");
            function f5() {
            }
            var a_2 = f5();
            function f6() {
            }
            var Math_2 = f6((c = 1 + c, (("function" && 25) | -4 ^ []) & (undefined_2 && (undefined_2.null = (c = c + 1, 
            24..toString()) >> -3 / false))), (c = 1 + c, ("b" === "c" === "undefined" >> -3) <= (/[a2][^e]+$/ >> false) % (2 << ([ , 0 ].length === 2))), "c");
        }
        var b_2 = f2(0 === 1 ? a : b, [ (c = 1 + c, b_2 && (b_2.a = (this << false < (23..toString() <= 2)) % (b_2 = ([] || "function") / (-1, 
        22)))), (c = 1 + c, b_2 && (b_2[~a] = ([ , 0 ].length === 2) < ([ , 0 ].length === 2) <= "number" % 5 >= ("c" << 1 !== "b" << 23..toString()))) ]);
        function f7(a_1) {
            {
                var brake1 = 5;
                do {
                    c = 1 + c, (0 << 25, NaN && 2) + (([ , 0 ][1] != "foo") > ("bar" !== NaN));
                } while ((c = 1 + c, (/[a2][^e]+$/ !== "a" && "b" ^ [ , 0 ].length === 2) & NaN * /[a2][^e]+$/ !== ([ , 0 ][1] | NaN)) && --brake1 > 0);
            }
            if (c = 1 + c, false > -2 > (4 > 22) ^ !(c = c + 1, 1)) {
                c = 1 + c, a_1 && (a_1.b += (a_1 = -5 % -0 << (24..toString() ^ "a")) * (delete ([ , 0 ].length === 2) | null + "foo"));
            } else {
                c = 1 + c, ("function" >>> "c" > ("a" >= "a")) + (("undefined", "c") <= (b_2 && (b_2[c = 1 + c, 
                [ , 0 ][1] >> "bar" >= (c = c + 1, 3) === ((c = c + 1, [ , 0 ].length === 2) !== {} - 0)] = 0 >>> 24..toString())));
            }
        }
        var b = f7();
    }
    var undefined_2 = f1("c", (c = c + 1) + (b += a));
    function f8(b_2, parseInt_2, Math) {
        {
            var brake7 = 5;
            L23959: while (new function() {}() && --brake7 > 0) {
                var brake8 = 5;
                while (b_2 && --brake8 > 0) {
                    undefined_2;
                }
            }
        }
    }
    var bar_1 = f8(23..toString());
    function f9(b_1, NaN_1) {
        try {
            {
                var expr12 = (c = c + 1) + (b + 1 - .1 - .1 - .1);
                for (var key12 in expr12) {
                    try {
                        switch (c = 1 + c, ((c = c + 1, -3) === /[a2][^e]+$/ + Infinity) > ((undefined_2 = "c" >>> 24..toString()) <= ("b", 
                        [ , 0 ].length === 2))) {
                          case c = 1 + c, ("number" ^ "b") / ([ , 0 ].length === 2 ^ -4) ^ ("" >= Infinity | (NaN_1 && (NaN_1[c = 1 + c, 
                            (NaN_1 && (NaN_1[(c = 1 + c, undefined_2 && (undefined_2.undefined >>= (-5 && -4 || (this || "b"), 
                            (-2 | 3) == (Infinity || -3)))) ? (c = 1 + c, ~((-3 || true) !== ([ , 0 ][1] != null))) : (c = 1 + c, 
                            delete (-5 % -4 <= (b_1 = "foo" || -3)))] = (22 && [ , 0 ][1]) >>> this / 5)) | 1 - 23..toString() > void 5] %= -0 / 3))):
                            ;
                            break;

                          case c = 1 + c, (1 - "foo" < ({} && NaN)) - (this ^ -2) / ("function" - "number"):
                            ;
                            break;

                          default:
                            ;

                          case c = 1 + c, Infinity <= 1 | (NaN | Infinity) || (c = c + 1, 23..toString()) > -5 - 22:
                            ;
                            break;
                        }
                    } catch (undefined_2_2) {
                        c = 1 + c, ([ , 0 ][1] !== this) >>> ("bar" << null) | (NaN, -4, {} >= 25);
                        c = 1 + c, +(NaN <= "undefined") << (b_1 += (-3 >>> "object") - (undefined_2 = true !== []));
                    }
                }
            }
        } finally {
            L23960: {
                c = 1 + c, (undefined >> [] ^ "c" & false) != "" / true - (this != "");
            }
            {
                var NaN_1_2 = function Infinity(arguments_1) {
                }((c = 1 + c, (undefined_2 && (undefined_2.Infinity = (38..toString() || "") ^ (1 ^ 23..toString()))) >>> (23..toString() - ([ , 0 ].length === 2) ^ (-5, 
                5))), "", (c = 1 + c, (bar_1 && (bar_1[void function Math() {
                }()] = (38..toString() || "bar") ^ "b" <= 22)) > (5 === [] !== ("object" == "c"))));
            }
        }
    }
    var a_2 = f9((c = c + 1) + -(-4 + 25 > -"number", bar_1 && (bar_1[(c = c + 1) + --b] = (0 != "object") >> (Infinity > 23..toString()))), typeof bar_1 == "function" && --_calls_ >= 0 && bar_1(22, [ (c = 1 + c, 
    (25 || true) / (undefined_2 && (undefined_2[c = 1 + c, bar_1 -= (undefined_2 && (undefined_2[c = 1 + c, 
    (1 - [], -0 <= []) !== (a_2 && (a_2.var = (true ^ "object") < ({} | [])))] <<= 22 - this)) >= (-5 <= false) || "foo" > 3 != ("foo" != "undefined")] ^= "a" % true)) != (bar_1 && (bar_1.foo = (bar_1 ^= 2 ^ false) >= ("" !== "object")))), (c = 1 + c, 
    (a_2 && (a_2.c = Infinity % "foo" && true % "foo")) + (-4 | undefined | false % {})), (c = 1 + c, 
    ((-4 ^ {}) <= (22 & 2)) % ((0 != -4) < (bar_1 = 2 + "foo"))), (c = 1 + c, ([ , 0 ][1] % "a" | ~"number") < ((38..toString() && "a") <= (-0 & undefined))) ][[ (c = 1 + c, 
    ({} < Infinity) >> (a_2 && (a_2[c = 1 + c, ((2 >> false) - (-1 === /[a2][^e]+$/)) / (-2 % 1 || ([ , 0 ].length === 2) * Infinity)] = /[a2][^e]+$/ / -0)) | (c = c + 1, 
    true ^ -1)), (c = 1 + c, (([ , 0 ].length === 2) < 24..toString() ^ -1 != "a") - (false <= 22 & [] >= -3)) ].null], !a), b--);
}

var bar = f0();

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

// uglified code
// (beautified)
var a = 10, t = 10, r = 0;

!function() {
    var i = function() {
        var n, a, o = (n = i, a = 1 + a, (r = 1 + r, o && (o.a = (this << !1 < !1) % (o = 0)), 
        r = 1 + r, o && (o[-101] = !0)).null = !1, a = 1 + a, n && (n.null = (a += 1, 24)), 
        void (a = 1 + a)), i = function(n) {
            for (var a = 5; r = 1 + (1 + r), 0 < --a; ) {}
            r = 1 + r, !0 ^ (r += 1, !1) ? (r = 1 + r, n && (n.b += n = 0)) : (r = 1 + r, o && (o[r = 1 + r, 
            r += 1, 0 == (NaN !== (r += 1, !0))] = 0));
        }();
    }((r += 1, t += 100)), f = function() {
        for (var n = 5; new function() {}() && 0 < --n; ) {
            for (var a = 5; 0 < --a; ) {}
        }
    }(), n = function(n) {
        try {
            var a = (r += 1) + (t + 1 - .1 - .1 - .1);
            for (var o in a) {
                try {
                    switch (r = 1 + r, (i = 0) <= !0 < !1) {
                      case r = 1 + (r += 1), -0 ^ (!1 | (n && (n[r = 1 + r, !1 | (n && (n[r = 1 + r, i && (i.undefined >>= !1) ? (r = 1 + r, 
                        -2) : (r = 1 + r, !0)] = 0 >>> this / 5))] %= -0))):
                      case r = 1 + r, !1 - (-2 ^ this) / NaN:
                        break;

                      default:
                      case r = 1 + r, r += 1, !0:
                    }
                } catch (n) {
                    r = 1 + (r = 1 + r), i = !0;
                }
            }
        } finally {
            r = 1 + (r = 1 + r), i && (i.Infinity = 48), r = 1 + r, f && (f[void 0] = 38);
        }
    }((r += 1, f && (f[(r += 1) + --t] = 0), "function" == typeof f && 0 <= --a && f(22, [ (r = 1 + r, 
    25 / (i && (i[r = 1 + r, f -= !0 <= (i && (i[r = 1 + r, !0 !== (n && (n.var = !1))] <<= 22 - this)) || !0] ^= NaN)) != (f && (f.foo = !0 <= (f ^= 2)))), (r = 1 + r, 
    (n && (n.c = NaN)) + -4), !0 % (!0 < (f = "2foo")), !0 ][[ (r = 1 + (1 + (1 + r)), 
    !1 >> (n && (n[r = 1 + r, 0] = NaN)) | -2), (r = 1 + (r + 1), -1) ].null], !1)), t--);
}(), console.log(null, 100, t, r, 1 / 0, NaN, void 0);

original result:
null 100 109 21 Infinity NaN undefined

uglified result:
evalmachine.<anonymous>:1
(function(){var a=10,t=10,r=0;!function(){var i=function(){var n,a,o=(n=i,a=1+a,(r=1+r,o&&(o.a=(this<<!1<!1)%(o=0)),r=1+r,o&&(o[-101]=!0)).null=!1,a=1+a,n&&(n.null=(a+=1,24)),void(a=1+a)),i=function(n){for(var a=5;r=1+(1+r),0<--a;);r=1+r,!0^(r+=1,!1)?(r=1+r,n&&(n.b+=n=0)):(r=1+r,o&&(o[r=1+r,r+=1,0==(NaN!==(r+=1,!0))]=0))}()}((r+=1,t+=100)),f=function(){for(var n=5;new function(){}&&0<--n;)for(var a=5;0<--a;);}(),n=function(n){try{var a=(r+=1)+(t+1-.1-.1-.1);for(var o in a)try{switch(r=1+r,(i=0)<=!0<!1){case r=1+(r+=1),-0^(!1|(n&&(n[r=1+r,!1|(n&&(n[r=1+r,i&&(i.undefined>>=!1)?(r=1+r,-2):(r=1+r,!0)]=0>>>this/5))]%=-0))):case r=1+r,!1-(-2^this)/NaN:break;default:case r=1+r,r+=1,!0:}}catch(n){r=1+(r=1+r),i=!0}}finally{r=1+(r=1+r),i&&(i.Infinity=48),r=1+r,f&&(f[void 0]=38)}}((r+=1,f&&(f[(r+=1)+--t]=0),"function"==typeof f&&0<=--a&&f(22,[(r=1+r,25/(i&&(i[r=1+r,f-=!0<=(i&&(i[r=1+r,!0!==(n&&(n.var=!1))]<<=22-this))||!0]^=NaN))!=(f&&(f.foo=!0<=(f^=2)))),(r=1+r,(n&&(n.c=NaN))+-4),!0%(!0<(f="

TypeError: Cannot set property 'null' of undefined
    at evalmachine.<anonymous>:1:144
    at evalmachine.<anonymous>:1:327
minify(options):
{
  "compress": {
    "passes": 1000000,
    "unsafe": true
  },
  "toplevel": true
}