ufuzz failure

[alexlamsl]

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

function f0(a, arguments_1) {
    if (--b + {
        c: Infinity,
        get undefined() {
            switch (1 === 1 ? a : b) {
              case --b + a++:
                break;

              case a++ + void ((arguments_1 <<= -0 > 23..toString() ^ 0 >= 22) <= ((-5 && "foo") & ("number" || []))):
                /[abc4]/g.exec(((c = c + 1) + ((c = 1 + c, void (-5 >> "a", [ , 0 ].length === 2 == 4)) || a || 3).toString() || b || 5).toString());
                if ({
                    0: (c = 1 + c, 25 / 5 % ("c" % [ , 0 ][1]) == ("b" & NaN && "object" ^ 38..toString()))
                }[[].b]) {
                    for (var brake5 = 5; --b + (typeof f0 == "function" && --_calls_ >= 0 && f0((c = 1 + c, 
                    arguments_1 && (arguments_1[a++ + b--] = (("" !== "number") < (true < 0)) >>> ((2 == -2) >>> ([ , 0 ].length === 2) + 38..toString()))), (c = 1 + c, 
                    ("a", 5) <= (arguments_1 && (arguments_1[c = 1 + c, (arguments_1 && (arguments_1[1 === 1 ? a : b] += (-2 && "a", 
                    "bar" >= 4))) ^ (arguments_1 && (arguments_1[c = 1 + c, (-4 & "a") - (22 !== "a") & (-2 || null && "b")] = "foo" % this)) % (-3 ^ null)] *= "a" * 24..toString())) & (c = c + 1, 
                    c = c + 1, -3)))) && brake5 > 0; --brake5) {
                        L23049: {
                        }
                    }
                }
                break;

              default:
              case [ a++ + (!function arguments() {
                }() ? +a : --b + {
                    in: (c = 1 + c, (3 | -4) * (4 ^ 23..toString()) != ("foo" !== "object") >> 38..toString() % -4),
                    "": (c = 1 + c, c = c + 1, 3 !== 25 | (c = c + 1, "function"))
                }), {
                    b: (c = 1 + c, (Infinity >> 23..toString() << (NaN, true)) * ("bar" >> -4 > ("function" | "number"))),
                    NaN: (c = 1 + c, (arguments_1 && (arguments_1.Infinity = "function" >= "object")) >= this / "c" ^ (arguments_1 = [ , 0 ][1] & "" ^ 22 <= 2)),
                    0: (c = 1 + c, (c = c + 1, 3 + "number") || ("object" && "c") == 38..toString() + -2),
                    b: (c = 1 + c, -4 & 5 & "bar" === 38..toString() ^ NaN - "b" < NaN - 38..toString())
                }.in, (arguments_1 && (arguments_1.a = true >= 25 !== (-0 || "function"))) / ("a" << undefined == 24..toString() << 38..toString()), --b + a++ ? arguments_1 : 1 === 1 ? a : b ]:
                {
                    var foo_1 = function f1(b_2) {
                        c = 1 + c, ((arguments_1 |= [] <= -0) > ("bar" !== "object")) >> ("function" * -4 >>> ({}, 
                        "function"));
                        c = 1 + c, ((0 ^ this) == (b_2 && (b_2.a = 4 - NaN))) << -0 * 3 % (-3 * "bar");
                    }();
                }
                (function() {
                });
                break;
            }
            return;
        },
        1.5: b &= a,
        "-2": a++ + (1 === 1 ? a : b),
        3: arguments_1 && arguments_1[a--]
    }.undefined) {
        undefined;
    }
    try {
        L23050: for (var brake14 = 5; delete ((c = c + 1, -5) - ("" ^ 5)) && brake14 > 0; --brake14) {
            var brake15 = 5;
            do {
                {
                    var expr16 = a++ + delete a;
                    L23051: for (var key16 in expr16) {
                        break L23050;
                    }
                }
            } while (typeof f3 == "function" && --_calls_ >= 0 && f3() && --brake15 > 0);
        }
    } catch (b_1) {
        switch (a++) {
          default:
            {
                var brake19 = 5;
                L23052: while ([ --b + delete ((b_1 && (b_1[(c = c + 1) + /[abc4]/g.exec(((c = 1 + c, 
                (arguments_1 <<= (-2 & "foo") >>> (arguments_1 && (arguments_1[c = 1 + c, arguments_1 && (arguments_1[--b + (typeof arguments_1 == "function" && --_calls_ >= 0 && arguments_1())] += 4 - "" == this >>> 4) && (Infinity && this, 
                /[a2][^e]+$/ ^ "b")] += "undefined" % "b"))) >= (Infinity ^ -1) >> undefined / -0) || b || 5).toString())] %= (24..toString() == 25, 
                "bar" && "object"))) === (NaN !== -0) - (-4 ^ null)) ][a++ + /[abc4]/.test(((c = c + 1) + {
                    3: (c = 1 + c, delete false << (-4 != Infinity) !== (("function", "number") && 1 == 2)),
                    c: (c = 1 + c, (24..toString() << "b") % (25 === -5) << ("undefined" + -2) * ({} ^ "object")),
                    b: (c = 1 + c, (c = c + 1, [] ^ Infinity) === (null !== "" & "b" >= "foo")),
                    get a() {
                        c = 1 + c, arguments_1 && (arguments_1.NaN >>= -("object" & undefined) !== (3 < NaN) / (38..toString() ^ [ , 0 ][1]));
                    }
                } || b || 5).toString())] && --brake19 > 0) {
                    return arguments_1 /= /[abc4]/.test((--b + ((b_1 && (b_1[--b + (typeof f2 == "function" && --_calls_ >= 0 && f2(4, 2))] += -4 / undefined * ("a" && -5))) ^ (-5 || "b") << (4, 
                    "object")) || b || 5).toString());
                }
            }
            if ((c = c + 1) + arguments_1) {
                var a = --b + b++, foo = (/[abc4]/.test((--b + {
                    c: (c = 1 + c, (c = c + 1, [ , 0 ][1]) / (22 | "bar") << (true >> /[a2][^e]+$/ << ("foo" >>> 5)))
                } || b || 5).toString()) || a || 3).toString();
            }

          case --b + {
                var: (c = c + 1) + void (b_1 && (b_1.undefined = !(-2 >= 1) << (("function", "bar") & 22 / "a")))
            }[!function NaN_2() {
                switch ({
                    1.5: (c = 1 + c, (NaN / "bar", 24..toString() >>> 1) == ("c" >>> Infinity != 38..toString() << "a")),
                    "\t": (c = 1 + c, void (c = c + 1, {}), -"", Infinity === "number"),
                    null: (c = 1 + c, 4 < [ , 0 ][1] != -2 * 23..toString() ^ ("function" | NaN | "c" - /[a2][^e]+$/)),
                    1.5: (c = 1 + c, (b_1 += 1 * false, "object" & "function") * (this >= -4 < true >>> []))
                }) {
                  default:
                  case {
                        "\t": (c = 1 + c, -1 % 38..toString() <= (4 <= "") == (null, 2, "number" >> "b"))
                    }:
                    {
                        return;
                        c = 1 + c, "bar" >>> "a" >> (b_1 && (b_1[c = 1 + c, (-3 / 3 >= 5 - -4) + (b_1 && (b_1[(c = c + 1) + (b = a)] = [ , 0 ].length === 2 != 0 ^ -0 <= 25))] += "a" == Infinity)) >= (c = c + 1, 
                        NaN_2 += "b" <= /[a2][^e]+$/);
                    }
                    if (c = 1 + c, (b_1 && (b_1.in %= (false, 0) + ("bar" || 4))) <= ("c" == ([ , 0 ].length === 2) !== ("bar" & "a"))) {
                        c = 1 + c, ("function" - {} >>> (-3 >= 23..toString())) / (("bar" << Infinity) % (0 >> 1));
                    }
                    break;

                  case a++ + ((-4 != 23..toString()) - "object" / ([ , 0 ].length === 2) | -5 % 1 >> (-4 & true)):
                    break;

                  case +function() {
                        c = 1 + c, ((Infinity && 3) > -22) >> (0 + this !== -1 < 5);
                        c = 1 + c, (false & [ , 0 ].length === 2 ^ "bar" === -3) != (arguments_1 && (arguments_1[c = 1 + c, 
                        (this - "function" !== (b_1 *= 38..toString() >= 25)) >>> (b_1 = 1 == "b" ^ {} << undefined)] = 4 <= 25)) - 0 * "bar";
                        c = 1 + c, NaN_2 && (NaN_2.var = "object" - [ , 0 ][1] <= (b_1 && (b_1.undefined = "b" * "bar")) | ("b" >= 5) % (null & 25));
                    }():
                    var c_1 = (c = 1 + c, 5 >>> null >>> (undefined | []) >= (b_1 = (-4 && NaN) ^ 2 == 23..toString()));
                    L23053: for (var brake32 = 5; (c = 1 + c, ("function" ^ -2) != (Infinity && -5) !== "object" >> NaN >> (/[a2][^e]+$/ >>> 2)) && brake32 > 0; --brake32) {
                        c = 1 + c, -2 % "bar" & -0 >= null ^ (5 || "b") <= (c = c + 1, 5);
                    }
                    break;
                }
                c = c + 1;
                {
                    var brake35 = 5;
                    L23054: do {
                        (c = c + 1) + {}.length;
                    } while ((c = c + 1) + void function() {
                        c = 1 + c, (null < "bar") / ("b" === -2) > 3 % 38..toString() - (3 || 0);
                        c = 1 + c, ("function" != "c" !== (NaN_2 && (NaN_2[c = 1 + c, c_1 && (c_1[[ (c = 1 + c, 
                        (-3 + -1 === (c = c + 1, 0)) >> (this + "object" >= 5 * /[a2][^e]+$/)), (c = 1 + c, 
                        -4 <= "number" & "number" >= "function" | (arguments_1 && (arguments_1.c = (-0 && this) - false % 23..toString()))), (c = 1 + c, 
                        ([ , 0 ][1] >>> 1, -1 * "b") !== (b_1 && (b_1[void function() {
                        }()] |= undefined % Infinity != (-5 == [])))), (c = 1 + c, (c_1 && (c_1[typeof f2 == "function" && --_calls_ >= 0 && f2((c = 1 + c, 
                        (23..toString() > 24..toString() && (arguments_1 <<= -0 ^ this)) <= (arguments_1 = (true & [ , 0 ][1]) - ("bar" | this))), (c = 1 + c, 
                        (true ^ "foo") !== ("bar" !== "number") ^ (b_1 += delete -2 - (c_1 && (c_1[c = 1 + c, 
                        -((NaN_2 += -1 == 23..toString()) * (b_1 += "c" + 5))] = /[a2][^e]+$/ - 1)))))] += (4 != 38..toString(), 
                        this !== Infinity))) * ({} % 3 <= (undefined | 5))) ][--b + c_1]] = (("foo" <= null) >>> -"b", 
                        2 != ([ , 0 ].length === 2) == (c = c + 1, 4)))] += "bar" != ([ , 0 ].length === 2)))) << (b_1 && (b_1.c += (false == 3) - (true !== "object")));
                        c = 1 + c, ((NaN_2 && (NaN_2[c = 1 + c, ("undefined" == [ , 0 ][1]) >> ("object" || "foo") > (arguments_1 && (arguments_1.var += (-0 && "a") != (this ^ NaN)))] += /[a2][^e]+$/ < 38..toString())) !== 2 >> true) >= (b_1 && (b_1[a++ + ((false > "") << "number" % "number" | ([ , 0 ][1] <= -0) % ("number" >= "number"))] += 3 % 5 <= (c_1 += [ , 0 ].length === 2 | "undefined")));
                        c = 1 + c, (NaN_2 && (NaN_2.c |= -0 > 5), undefined / ([ , 0 ].length === 2)) ^ (null == Infinity) >= (-4 !== /[a2][^e]+$/);
                    }() && --brake35 > 0);
                }
                switch ((c = c + 1) + (typeof f2 == "function" && --_calls_ >= 0 && f2((c = 1 + c, 
                (c = c + 1, 4 ^ "") + (({} | Infinity) - ("object" | -2))), (c = 1 + c, (-3 / "" >= ([ , 0 ][1] ^ 24..toString())) >> ((4 <= -0) >> (b_1 && (b_1.NaN /= false ^ Infinity)))), -0))) {
                  case {}:
                    break;

                  case (c = c + 1) + [ (c = 1 + c, 24..toString() > "number" & (c_1 = "object" % 1) && (c_1 %= null == -0 ^ (24..toString(), 
                    -1))), (c = 1 + c, c = c + 1, undefined <= 22 | "a" >>> {}), (c = 1 + c, (c = c + 1, 
                    c = c + 1, 2) != ("a" << 3) + (this == "b")) ]:
                    c = c + 1;
                    break;

                  case b = a:
                    break;

                  case --b + (1 === 1 ? a : b):
                    break;
                }
            }()]:
            var bar_1;
            L23055: {
                {
                    var Math_2 = function f2(undefined_2, foo_1, b_1) {
                        c = 1 + c, (2 <= 24..toString() != 38..toString() < 5) << (b_1 = -1 & 24..toString()) - ("foo" !== null);
                        c = 1 + c, ("bar" < 38..toString() !== 38..toString() + 23..toString()) % (5 <= "a" != (0, 
                        -2));
                    }((c = 1 + c, -3 * "foo" < (25 ^ -1) != (false <= undefined) >>> (arguments_1 && (arguments_1.b *= "c" || "object"))));
                }
                if (typeof bar_1 == "function" && --_calls_ >= 0 && bar_1("a")) {
                    var brake49 = 5;
                    L23056: do {
                        c = 1 + c, - -0 > /[a2][^e]+$/ + -5 == ("c" ^ "bar") > (this ^ 23..toString());
                    } while ((b %= a) && --brake49 > 0);
                }
                c = c + 1;
                var Infinity_1 = --b + a++;
            }
            break;

          case ~(b_1 && (b_1.undefined += (3 <= [] <= -2 + 2) << (0 >> "foo" > -1 % false))):
            switch (1 === 1 ? a : b) {
              case (c = c + 1) + ((c = c + 1) + (bar_1 = bar_1) || 2).toString()[[ typeof f3 == "function" && --_calls_ >= 0 && f3(undefined, (c = 1 + c, 
                Infinity_1 >>>= (false > "number") + 38..toString() % undefined >>> (bar_1 && (bar_1[{
                    c: (c = 1 + c, (undefined !== NaN) + (25 | Infinity) + ((0 && 2) < "b" >>> 3))
                }] += ([ , 0 ].length === 2 & -2) - (-0 | -1)))), {}), b++, , --b + (typeof undefined_1 === "function") ]]:
                break;

              case (c = c + 1) + ({
                    3: typeof f3 == "function" && --_calls_ >= 0 && f3("number", "undefined"),
                    c: (c = c + 1) + function() {
                    }(),
                    null: a++ + ((c = 1 + c, c = c + 1, !true < ("bar" !== {})) || 5).toString()[c = 1 + c, 
                    ((24..toString() && Infinity) != (24..toString(), 0)) >> (-5 < "") - ("number" - null)],
                    0: (c = c + 1) + /[abc4]/.test(((c = 1 + c, (("b" != 2) <= (-5, null)) % (3 || -5, 
                    -3 & -4)) || b || 5).toString())
                } || 3).toString()[(c = c + 1) + void function arguments_1() {
                    c = 1 + c, ((-0, [ , 0 ][1]) ^ "undefined" < -1) % (24..toString() + 23..toString() >> (b_1 && (b_1[c = 1 + c, 
                    arguments_1 /= ([ , 0 ][1] ^ 4) + (bar_1 && (bar_1[c = 1 + c, +"foo" / (-1 - []) + (true >> true << "foo" * -5)] = 3 + 24..toString())), 
                    24..toString() <= 3 ^ (arguments_1 = "bar" >>> 4)] >>= [] <= 38..toString())));
                }()]:
                break;

              case typeof f2 == "function" && --_calls_ >= 0 && f2():
                L23057: for (var brake56 = 5; (c = c + 1) + b-- && brake56 > 0; --brake56) {
                    var arguments = (c = 1 + c, -0 << -4 > ([ , 0 ].length === 2) + -4 | "object" !== "object" & "object" * 1);
                }
                {
                    var brake58 = 5;
                    L23058: do {
                        {
                            var expr59 = (c = c + 1) + 5;
                            for (var key59 in expr59) {
                                c = 1 + c;
                                var Infinity_1 = expr59[key59];
                                {
                                    var brake60 = 5;
                                    L23059: while ((c = 1 + c, ((c = c + 1, 0) != "number" <= 4) >>> (c = c + 1, ([ , 0 ].length === 2) % [])) && --brake60 > 0) {
                                        c = 1 + c, "b" ^ 0 ^ ([ , 0 ].length === 2) <= [] || (Math_2 && (Math_2[c = 1 + c, 
                                        (c = c + 1, "") > 25 - "undefined" | (24..toString() & "foo") == ("foo" == NaN)] = "object" ^ /[a2][^e]+$/)) >= 23..toString() % [];
                                    }
                                }
                            }
                        }
                    } while (a++ + void (Math_2 = (NaN ^ null && "function" < "bar") == ("foo" & -0) <= 0 >>> true) && --brake58 > 0);
                }
                break;

              case a--:
                {
                    var expr62 = void function Math_2_2() {
                        c = 1 + c, ("undefined" ^ Infinity) % (undefined + "undefined") << ((-2, "c") >= "number" - -1);
                        c = 1 + c, ([ , 0 ].length === 2 ^ this ^ (Math_2_2 += [ , 0 ].length === 2 !== "b")) === 25 > this < ("object" >= "undefined");
                        c = 1 + c, bar_1 && (bar_1[[ , (c = 1 + c, (-1 & -2 | (b_1 = 22 == [])) >>> (38..toString() / true >= ([] != -3))), (c = 1 + c, 
                        (Math_2_2 = /[a2][^e]+$/ >>> NaN) % ("c" & "object") || Infinity === "undefined" == 4 << "b") ].in] += (24..toString() > 2 || Math_2_2 && (Math_2_2[c = 1 + c, 
                        (c = c + 1, this) + Infinity % false + (4 / "b" == (-5 | this))] += [] % -1)) === (Math_2_2 && (Math_2_2.c += (-1 === 5) <= (false === "c"))));
                        c = 1 + c, ("" ^ 22) >> [ , 0 ][1] + -1 >> (24..toString() === [] & (b_1 && (b_1.NaN += "b" === "")));
                    }();
                    L23060: for (var key62 in expr62) {
                        c = 1 + c;
                        var b_2 = expr62[key62];
                        {
                            c = 1 + c, /[a2][^e]+$/ % false * ("undefined" != -2) | (25 > Infinity) + (c = c + 1, 
                            "foo");
                            c = 1 + c, (/[a2][^e]+$/ != NaN, -2 - -0) >= (arguments_1 && (arguments_1.undefined = (b_1 && (b_1.NaN = this != 5)) >>> (-3 < undefined)));
                            c = 1 + c, (([] || -1) == ("b" != -4)) << ((b_2 && (b_2.undefined = (-5, 3))) ^ 22 * false);
                            c = 1 + c, "object" % 2 - (null !== undefined) ^ "c" << true > [] - false;
                        }
                    }
                }
                break;
            }
            ;
            break;

          case (--b + ((b = a) ? Infinity_1 : b >>>= a) || 6).toString()[[ a++ + void function() {
                {
                }
                c = c + 1;
                return c = 1 + c, true != this ^ {} != undefined | (arguments_1 += 23..toString() ^ 3) + ("object" || 0);
                {
                    var brake76 = 5;
                    do {
                        c = 1 + c, (25 ^ 24..toString() | "undefined" ^ "b") === 2 % -5 + ("number" < 1);
                    } while ((c = 1 + c, (null & -4) >= "function" / -2 < (Infinity === "foo") * (null & [ , 0 ].length === 2)) && --brake76 > 0);
                }
            }(), --b + (b_1 && b_1.undefined), --b + (b = a), typeof f3 == "function" && --_calls_ >= 0 && f3(b + 1 - .1 - .1 - .1, "bar"), (c = c + 1) + /[abc4]/g.exec(({
                length: (c = 1 + c, ~(-4 % -0) < -(false - "object")),
                0: (c = 1 + c, -(([ , 0 ][1] & "function") >> (24..toString() & 1))),
                set NaN(b_2) {
                    this.b = 0 > true;
                }
            }[a++ + (typeof bar_1 == "function" && --_calls_ >= 0 && bar_1((c = 1 + c, ([ , 0 ].length === 2, 
            25) > "number" >> undefined != (NaN >> "bar") % ("foo" ^ "foo"))))] || b || 5).toString()) ][--a]]:
        }
        {
            var brake78 = 5;
            while (typeof f0 == "function" && --_calls_ >= 0 && f0() && --brake78 > 0) {
                var c_2 = a++ + (typeof f3 == "function" && --_calls_ >= 0 && f3()), Math = (c = c + 1) + (typeof Infinity_1 == "function" && --_calls_ >= 0 && Infinity_1());
            }
        }
    } finally {
        {
            switch (--b + (1 === 1 ? a : b)) {
              default:
                var bar = a++ + 23..toString(), b = (c = c + 1) + (--b + (typeof f0 == "function" && --_calls_ >= 0 && f0(NaN, [ , 0 ][1], (c = 1 + c, 
                (c_2 && (c_2[c = 1 + c, 1 >>> 3 < (undefined | 38..toString()) ^ ((Infinity_1 && (Infinity_1[c = 1 + c, 
                ([] >> "foo", 4 && false) <= (Infinity_1 && (Infinity_1.var = (c = c + 1, -5) > Infinity * 2))] += 4 !== -3)) ^ "bar" - -0)] += "b" <= -2)) + ("foo" === 25) >= (-4 * -1 != ({} & -1))))));
                L23061: for (var brake83 = 5; (1 === 1 ? a : b) && brake83 > 0; --brake83) {}

              case --b + /[abc4]/.test((a++ + ((c = c + 1) + a--) || b || 5).toString()):
              case --b + /[abc4]/.test(([ (c = c + 1) + ((c = 1 + c, (23..toString() <= "a") - ("function" >= "object") ^ 22 == 23..toString() !== (b_2 && (b_2.var = true & null))) ? (c = 1 + c, 
                ([] && true) >= ("object" === -5) | ("" !== 38..toString()) << -3 * NaN) : (c = 1 + c, 
                b_2 <<= (false, NaN, 23..toString() - -3) == (bar_1 && (bar_1.in += (b_2 && (b_2.null = 1 && "function")) == 22 / false)))), --b + {
                    foo: (c = 1 + c, c = c + 1, (undefined == 25) >= Infinity << 2)
                }[c = 1 + c, (Infinity_1 && (Infinity_1.null = (22 ^ this) / (([ , 0 ].length === 2) * 3))) == (Infinity !== "" == ({} || 3))], a++ + (c = 1 + c, 
                -3 + -5 + "" % -2 === (0 !== 5) + (([ , 0 ].length === 2) < 2)) ] || b || 5).toString()):
                try {
                    try {
                        switch (c = 1 + c, 25 >>> -1 === 0 * -2 == (([ , 0 ].length === 2 && null) == ("b", 
                        5))) {
                          case c = 1 + c, (-5 * Infinity | 25 <= "object") << ("" * NaN ^ 38..toString() > 5):
                            ;
                            break;

                          case c = 1 + c, (23..toString() + {} ^ (b_2 = [] >>> [])) & ([ , 0 ].length === 2 == 4) > (b_2 && (b_2.b = 23..toString() / true)):
                            ;

                          case c = 1 + c, c = c + 1, ("bar" === "number") + (this != "undefined"):
                            ;
                            break;

                          case c = 1 + c, (delete {} ^ undefined + "number") >= (3 <= -2 != (38..toString() == 1)):
                            ;
                            break;
                        }
                    } catch (Infinity_1) {
                        c = 1 + c, (2 + "object") % (arguments_1 && (arguments_1.Infinity |= 38..toString() & {})) << ("bar" >>> 4 >>> (25 >> -4));
                        c = 1 + c, (Infinity * 23..toString() >= [ , 0 ][1] / -4) - ([ , 0 ].length === 2 != 3 ^ 38..toString() === "object");
                    }
                } finally {
                    {
                    }
                    c = 1 + c, (22 <= Infinity <= (-1 || [ , 0 ][1])) * (Math_2 && (Math_2.c -= "object" !== "undefined" | (c = c + 1, 
                    24..toString())));
                }
                break;

              case a++ + (1 === 1 ? a : b):
                L23062: {
                    c = c + 1;
                    switch (c = 1 + c, ([ , 0 ].length === 2) >>> "object" << ("c" && "c"), (Infinity_1 += [ , 0 ].length === 2 ^ "undefined") || ("object" || "object")) {
                      default:
                        ;

                      case c = 1 + c, Math_2 && (Math_2.in = +(0 & null) >= (3 % undefined & void ([ , 0 ].length === 2))):
                        ;
                        break;

                      case c = 1 + c, (Infinity_1 && (Infinity_1[c = 1 + c, bar_1 && (bar_1.undefined /= (Infinity_1 && (Infinity_1.Infinity += 5 > Infinity)) > (Infinity_1 && (Infinity_1[c = 1 + c, 
                        "object" % -1 != (Math_2 = 24..toString() && /[a2][^e]+$/) ^ (-3 < 22 || Infinity_1 && (Infinity_1.undefined = "function" >>> "a"))] = /[a2][^e]+$/ >= -0)) != ((arguments_1 && (arguments_1[c = 1 + c, 
                        (-0 != "foo") < true >>> true <= ("undefined" === "foo" ^ 38..toString() - -5)] >>>= ("number", 
                        23..toString()))) ^ "object" <= 5))] += "number" | 25)) == -1 >>> "bar" ^ (c = c + 1, 
                        38..toString() > -0):
                        ;
                        break;

                      case c = 1 + c, (Infinity_1 && (Infinity_1[c = 1 + c, (([ , 0 ].length === 2) << this ^ (true && 22)) & (true - "b", 
                        this % 25)] %= /[a2][^e]+$/ != null) || [ , 0 ][1] >>> "undefined") + (-0 * -3 < ("c" <= "function")):
                        ;
                    }
                    L23063: for (var brake95 = 5; (c = 1 + c, ((undefined == 2) > ("foo" ^ -5)) + ((25 >>> []) + (4 < undefined))) && brake95 > 0; --brake95) {
                        c = 1 + c, b_2 && (b_2[(c = c + 1) + (Math_2 && Math_2.c)] += this - "object" >>> ([ , 0 ][1] >= "function") | (Math_2 && (Math_2[c = 1 + c, 
                        arguments_1 && (arguments_1.c = (-2 << Infinity & (Infinity_1 && (Infinity_1[c = 1 + c, 
                        (5 >= Infinity) + ("", "bar") >> void Infinity - (0 <= null)] = /[a2][^e]+$/ ^ "foo"))) % (this >>> "b" != "a" >= NaN))] = ("", 
                        [ , 0 ][1]))) >= ("b" !== {}));
                    }
                    {
                        var brake97 = 5;
                        do {
                            c = 1 + c, (38..toString() || "number") <= (this && "a"), ("a" >> "foo") % delete NaN;
                        } while ((c = 1 + c, (Math_2 && (Math_2[c = 1 + c, (0 - NaN | undefined ^ 1) != (([] || 24..toString()) ^ 24..toString() & 4)] = 38..toString() * "c")) << (NaN !== "c") ^ (24..toString() <= "b" ^ [] * 23..toString())) && --brake97 > 0);
                    }
                }
                break;
            }
            c = c + 1;
        }
        "foo";
    }
}

var a = f0("a", "function", 1);

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

// uglified code
// (beautified)
var x = 10, $ = 0, a = function e(i, c) {
    --g, {
        c: 1 / 0,
        get undefined() {
            switch (i) {
              case --g + i++:
                break;

              case i++ + void (c <<= 0):
                if ({
                    0: ($ = 1 + (1 + ($ + 1)), !1)
                }[[].b]) {
                    for (var a = 5; --g + (0 <= --x && e(($ = 1 + $, c && (c[i++ + g--] = 0)), ($ = 1 + $, 
                    5 <= (c && (c[$ = 1 + $, (c && (c[i] += !1)) ^ (c && (c[$ = 1 + $, -2] = "foo" % this)) % -3] *= NaN)) & ($ += 1, 
                    $ += 1, -3)))) && 0 < a; --a) {}
                }
                break;

              default:
              case [ i++ + +i, {
                    b: 0,
                    NaN: ($ = 1 + (1 + $), (c && (c.Infinity = !1)) >= this / "c" ^ (c = 0)),
                    0: "3number",
                    b: ($ = 1 + (($ = 1 + $) + 1), 0)
                }.in, (c && (c.a = !0)) / !1, --g + i++ ? c : i ]:
                c |= !0, $ = 1 + (1 + $), K && (K.a = NaN);
            }
        },
        1.5: g &= i,
        "-2": i++ + i,
        3: c && c[i--]
    }.undefined;
    try {
        a: for (var a = 5; $ += 1, 0 < a; --a) {
            var t = 5;
            do {
                var f = i++ + delete i;
                for (var n in f) {
                    break a;
                }
            } while ("function" == typeof f3 && 0 <= --x && f3() && 0 < --t);
        }
    } catch (n) {
        switch (i++) {
          default:
            var o = 5;
            if ([ --g + (n && (n[($ += 1) + /[abc4]/g.exec(($ = 1 + $, "" + (-1 <= (c <<= 0 >>> (c && (c[$ = 1 + $, 
            c && (c[--g + ("function" == typeof c && 0 <= --x && c())] += 4 == this >>> 4) && 0] += NaN))) || g || 5)))] %= "object"), 
            !0) ][i++ + /[abc4]/.test("" + (($ += 1) + {
                3: !0,
                c: 0,
                b: ($ = 1 + ($ = 1 + ($ = 1 + $)), 0 == ($ += 1, 0)),
                get a() {
                    $ = 1 + $, c && (c.NaN >>= !1);
                }
            } || g || 5))] && 0 < --o) {
                return c /= /[abc4]/.test("" + (--g + (-5 ^ (n && (n[--g + ("function" == typeof f2 && 0 <= --x && f2(4, 2))] += NaN))) || g || 5));
            }
            ($ += 1) + c && (i = --g + g++, --g, $ = 1 + $, $ += 1);

          case --g + {
                var: ($ += 1) + void (n && (n.undefined = 1))
            }[!function a() {
                switch ({
                    1.5: !1,
                    "\t": ($ = 1 + ($ = 1 + $), !1),
                    null: 1,
                    1.5: (n += 0, 0 * (-4 <= this < 1))
                }) {
                  default:
                  case {
                        "\t": ($ = 1 + ($ = 1 + ($ = 1 + ($ += 1))), !1)
                    }:
                    return;

                  case 0 + i++:
                    break;

                  case +function() {
                        $ = 1 + ($ = 1 + $), c && (c[$ = 1 + $, (this - "function" != (n *= !0)) >>> (n = 0)] = !0), 
                        $ = 1 + $, a.var = NaN <= (n && (n.undefined = NaN)) | NaN;
                    }():
                    for (var e = ($ = 1 + $, (n = 0) <= 5), t = 5; $ = 1 + $, 0 < t; --t) {
                        $ = 1 + $, $ += 1;
                    }
                }
                $ += 1;
                for (var f = 5; $ += 1, ($ += 1) + void function() {
                    $ = 1 + ($ = 1 + $), a[$ = 1 + $, e && (e[[ ($ = 1 + $, !1 >> (NaN <= this + "object")), ($ = 1 + ($ += 1), 
                    0 | (c && (c.c = -0))), ($ = 1 + $, NaN !== (n && (n[void 0] |= !0))), ($ = 1 + $, 
                    !1 * (e && (e["function" == typeof f2 && 0 <= --x && f2(!1 <= (c = 0 - ("bar" | this)), ($ = 1 + ($ = 1 + $), 
                    !0 ^ (n += !0 - (e && (e[$ = 1 + $, -((a + !1) * (n += "c5"))] = NaN)))))] += this !== 1 / 0))) ][--g + e]] = 1 == ($ += 1, 
                    4))] += !0, n && (n.c += -1), a[$ = 1 + ($ = 1 + $), (c && (c.var += -0 != (NaN ^ this))) < 0] += !0, 
                    n && (n[0 + i++] += 3 <= (e += 1)), $ = 1 + $, a.c |= !1;
                }() && 0 < --f; ) {}
                switch (($ += 1) + ("function" == typeof f2 && 0 <= --x && f2(($ = 1 + $, 6), ($ = 1 + ($ += 1), 
                !1 >> (!1 >> (n && (n.NaN /= 0)))), -0))) {
                  case {}:
                    break;

                  case ($ += 1) + [ !1 & (e = NaN), ($ = 1 + ($ = 1 + $), 0), ($ = 1 + ($ += 1), $ += 1, 
                    $ += 1, 2 != +("b" == this)) ]:
                    $ += 1;
                    break;

                  case g = i:
                  case --g + i:
                }
            }()]:
            var r, s = ($ = 1 + $, c && (c.b *= "c"), void ($ = 1 + ($ = 1 + $)));
            if ("function" == typeof r && 0 <= --x && r("a")) {
                for (var N = 5; $ = 1 + $, (g %= i) && 0 < --N; ) {}
            }
            $ += 1;
            var u = --g + i++;
            break;

          case ~(n && (n.undefined += 1)):
            switch (i) {
              case ($ += 1) + ("" + (($ += 1) + (r = r) || 2))[[ "function" == typeof f3 && 0 <= --x && f3(void 0, ($ = 1 + $, 
                u >>>= NaN >>> (r && (r[{
                    c: ($ = 1 + $, 26)
                }] += 1))), {}), g++, , --g + ("function" == typeof undefined_1) ]]:
              case ($ += 1) + ("" + {
                    3: "function" == typeof f3 && 0 <= --x && f3("number", "undefined"),
                    c: ($ += 1) + void 0,
                    null: i++ + ($ = 1 + $, ("" + !0)[$ = 1 + ($ += 1), 1]),
                    0: ($ += 1) + /[abc4]/.test(($ = 1 + $, "" + (g || 5)))
                })[($ += 1) + ($ = 1 + $, void (n && (n[$ = 1 + $, r && (r[$ = 1 + $, NaN] = "324"), 
                0] >>= !0)))]:
                break;

              case "function" == typeof f2 && 0 <= --x && f2():
                for (var d = 5; ($ += 1) + g-- && 0 < d; --d) {
                    $ = 1 + $;
                }
                var v = 5;
                do {
                    var b = ($ += 1) + 5;
                    for (var h in b) {
                        u = b[h], $ = 1 + ($ = 1 + $), $ += 1, $ += 1;
                    }
                } while (i++ + void (s = !1) && 0 < --v);
                break;

              case i--:
                var l = void function a() {
                    $ = 1 + ($ = 1 + ($ = 1 + $)), r && (r[[ , (-2 | (n = !1)) >>> !0, ($ = 1 + ($ = 1 + $), 
                    !1) ].in] += !0 === (a.c += !0)), $ = 1 + $, n && (n.NaN += !1);
                }();
                for (var y in l) {
                    $ = 1 + $;
                    var p = l[y];
                    $ = 1 + $, $ = 1 + ($ += 1), c && (c.undefined = (n && (n.NaN = 5 != this)) >>> !1), 
                    $ = 1 + $, p && (p.undefined = 3), $ = 1 + $;
                }
            }
            break;

          case ("" + (--g + ((g = i) ? u : g >>>= i) || 6))[[ i++ + ($ = 1 + ($ += 1), void (c += 20)), --g + (n && n.undefined), --g + (g = i), "function" == typeof f3 && 0 <= --x && f3(g + 1 - .1 - .1 - .1, "bar"), ($ += 1) + /[abc4]/g.exec("" + ({
                length: !1,
                0: ($ = 1 + ($ = 1 + $), -0),
                set NaN(a) {
                    this.b = !1;
                }
            }[i++ + ("function" == typeof r && 0 <= --x && r(($ = 1 + $, !0)))] || g || 5)) ][--i]]:
        }
        for (var k = 5; 0 <= --x && e() && 0 < --k; ) {
            var w = i++ + ("function" == typeof f3 && 0 <= --x && f3());
            $ += 1, "function" == typeof u && 0 <= --x && u();
        }
    } finally {
        switch (--g + i) {
          default:
            i++;
            for (var g = ($ += 1) + (--g + (0 <= --x && e(NaN, 0, ($ = 1 + $, w && (w[$ = 1 + $, 
            NaN ^ (u && (u[$ = 1 + $, !1 <= (u && (u.var = ($ += 1, !1)))] += !0)) ^ !0] += !1))))), j = 5; i && 0 < j; --j) {}

          case --g + /[abc4]/.test("" + (i++ + (($ += 1) + i--) || g || 5)):
          case --g + /[abc4]/.test("" + [ ($ += 1) + ($ = 1 + $, 1 ^ !1 !== (p && (p.var = 0)) ? ($ = 1 + $, 
            1) : ($ = 1 + $, p <<= 26 == (r && (r.in += (p && (p.null = "function")) == 1 / 0)))), --g + {
                foo: ($ = 1 + $, !0)
            }[$ = 1 + ($ += 1), 0 == (u && (u.null = (22 ^ this) / 3))], i++ + ($ = 1 + $, !1) ]):
            try {
                try {
                    switch (!1) {
                      case $ = 1 + ($ = 1 + $), 0:
                        break;

                      case $ = 1 + $, ("23" + {} ^ (p = 0)) & (p && (p.b = 23)) < !1:
                      case $ = 1 + $, $ += 1, !1 + ("undefined" != this):
                      case $ = 1 + $, !0:
                    }
                } catch (u) {
                    $ = 1 + $, c && (c.Infinity |= 0), $ = 1 + $;
                }
            } finally {
                $ = 1 + $, s && (s.c -= !0 | ($ += 1, "24"));
            }
            break;

          case i++ + i:
            switch ((u += 1) || "object") {
              default:
              case $ = 1 + ($ = 1 + ($ += 1)), s && (s.in = !0):
              case $ = 1 + $, 4294967295 == (u && (u[$ = 1 + $, r && (r.undefined /= (u && (u.Infinity += !1)) > (u && (u[$ = 1 + $, 
                NaN != (s = /[a2][^e]+$/) ^ !0] = !1)) != (!1 ^ (c && (c[$ = 1 + $, !0] >>>= "23"))))] += 25)) ^ ($ += 1, 
                !0):
                break;

              case $ = 1 + $, (u && (u[$ = 1 + $, (!0 << this ^ 22) & this % 25] %= !0) || 0) + !0:
            }
            for (var I = 5; $ = 1 + $, 0 < I; --I) {
                $ = 1 + $, p && (p[($ += 1) + (s && s.c)] += this - "object" >>> !1 | !0 <= (s && (s[$ = 1 + $, 
                c && (c.c = (-2 & (u && (u[$ = 1 + $, 0] = 0))) % (this >>> "b" != 0))] = 0)));
            }
            for (var m = 5; delete NaN, $ = 1 + ($ = 1 + $), (s && (s[$ = 1 + $, !0] = NaN)) << !0 ^ 1 && 0 < --m; ) {}
        }
        $ += 1;
    }
}("a", "function");

console.log(null, a, 10, $, 1 / 0, NaN, void 0);

original result:
null undefined 10 340 Infinity NaN undefined

uglified result:
evalmachine.<anonymous>:1
(function(){var x=10,$=0,a=function e(i,c){--g,{c:1/0,get undefined(){switch(i){case--g+i++:break;case i+++void(c<<=0):if({0:($=1+(1+($+1)),!1)}[[].b])for(var a=5;--g+(0<=--x&&e(($=1+$,c&&(c[i+++g--]=0)),($=1+$,5<=(c&&(c[$=1+$,(c&&(c[i]+=!1))^(c&&(c[$=1+$,-2]="foo"%this))%-3]*=NaN))&($+=1,$+=1,-3))))&&0<a;--a);break;default:case[i+++ +i,{b:0,NaN:($=1+(1+$),(c&&(c.Infinity=!1))>=this/"c"^(c=0)),0:"3number",b:($=1+(($=1+$)+1),0)}.in,(c&&(c.a=!0))/!1,--g+i++?c:i]:c|=!0,$=1+(1+$),K&&(K.a=NaN)}},1.5:g&=i,"-2":i+++i,3:c&&c[i--]}.undefined;try{a:for(var a=5;$+=1,0<a;--a){var t=5;do{var f=i+++delete i;for(var n in f)break a}while("function"==typeof f3&&0<=--x&&f3()&&0<--t)}}catch(n){switch(i++){default:var o=5;if([--g+(n&&(n[($+=1)+/[abc4]/g.exec(($=1+$,""+(-1<=(c<<=0>>>(c&&(c[$=1+$,c&&(c[--g+("function"==typeof c&&0<=--x&&c())]+=4==this>>>4)&&0]+=NaN)))||g||5)))]%="object"),!0)][i+++/[abc4]/.test(""+(($+=1)+{3:!0,c:0,b:($=1+($=1+($=1+$)),0==($+=1,0)),get a(){$=1+$,c&&(c.NaN>>=!1)}}||g||5)

ReferenceError: K is not defined
    at Object.get undefined [as undefined] (evalmachine.<anonymous>:1:482)
    at e (evalmachine.<anonymous>:1:530)
    at evalmachine.<anonymous>:1:4910
    at evalmachine.<anonymous>:1:4969
    at Script.runInContext (vm.js:133:20)
    at Object.runInContext (vm.js:311:6)
    at Object.exports.run_code (/home/runner/work/UglifyJS2/UglifyJS2/test/sandbox.js:65:12)
    at /home/runner/work/UglifyJS2/UglifyJS2/test/ufuzz/index.js:1142:37
    at Array.forEach (<anonymous>)
    at Object.<anonymous> (/home/runner/work/UglifyJS2/UglifyJS2/test/ufuzz/index.js:1135:51)

// reduced test case (output will differ)

function f0(arguments_1) {
    ({
        get undefined() {
            switch (0) {
              case 0 <= 0:
                f0((c = 0, 3));

              case 0:
                (function f1(b_2) {
                    b_2.a;
                })();
            }
        }
    }).undefined;
}

f0();
// output: TypeError: Cannot read property 'a' of undefined
// minify: ReferenceError: e is not defined
// options: {
//   "compress": {
//     "passes": 1000000,
//     "unsafe": true
//   },
//   "toplevel": true
// }

minify(options):
{
  "compress": {
    "passes": 1000000,
    "unsafe": true
  },
  "toplevel": true
}

Suspicious compress options:
  collapse_vars
  inline
  reduce_vars
  sequences
  unused

Suspicious options:
  rename

[kzc]

Strange... I can't reproduce this reduced test case using Node v10 or v12 with any flag combination - with or without PR #3742.

$ node-v10.4.1 bin/uglifyjs 3744.js -mc toplevel --reduce-test
// Node.js v10.4.1 on darwin x64
// reduce test pass 1, iteration 0: 35297 bytes
// reduce test pass 1, iteration 25: 35297 bytes
// reduce test pass 1, iteration 50: 35297 bytes
// reduce test pass 1, iteration 75: 35297 bytes
// reduce test pass 1, iteration 100: 35297 bytes
// reduce test pass 1, iteration 125: 35297 bytes
// reduce test pass 1, iteration 150: 35297 bytes
// reduce test pass 1, iteration 175: 35297 bytes
// reduce test pass 1, iteration 200: 35297 bytes
// reduce test pass 1, iteration 225: 35297 bytes
// reduce test pass 1, iteration 250: 35297 bytes
// reduce test pass 1, iteration 275: 35297 bytes
// reduce test pass 1, iteration 300: 35297 bytes
// reduce test pass 1, iteration 325: 35297 bytes
// reduce test pass 1, iteration 350: 35297 bytes
// reduce test pass 1, iteration 375: 35297 bytes
// reduce test pass 1, iteration 400: 35297 bytes
// reduce test pass 1, iteration 425: 35297 bytes
// reduce test pass 1, iteration 450: 35297 bytes
// reduce test pass 1, iteration 475: 35297 bytes
// reduce test pass 1, iteration 500: 35297 bytes
// reduce test pass 1, iteration 525: 35297 bytes
// reduce test pass 1, iteration 550: 35297 bytes
// reduce test pass 1, iteration 575: 35297 bytes
// reduce test pass 1, iteration 600: 35297 bytes
// reduce test pass 1, iteration 625: 35297 bytes
// reduce test pass 1, iteration 650: 35297 bytes
// reduce test pass 1, iteration 675: 35297 bytes
// reduce test pass 1, iteration 700: 35297 bytes
// reduce test pass 1, iteration 725: 35297 bytes
// reduce test pass 1, iteration 750: 35297 bytes
// reduce test pass 1, iteration 775: 35297 bytes
// reduce test pass 1, iteration 800: 35297 bytes
// reduce test pass 1, iteration 825: 35297 bytes
// reduce test pass 1, iteration 850: 35297 bytes
// reduce test pass 1, iteration 875: 35297 bytes
// reduce test pass 1, iteration 900: 35297 bytes
// reduce test pass 1, iteration 925: 35297 bytes
// reduce test pass 1, iteration 950: 35297 bytes
// reduce test pass 1, iteration 975: 35297 bytes
// reduce test pass 1: 35297 bytes
^C

It's stuck in an irreducible state. I had to kill the process after 5 minutes. Can you locally reproduce the reduced test case?

[kzc]

LOL - I had pasted both the original AND the uglified versions into 3744.js!

When I fixed the input it produced the same reduced result as you had.

[alexlamsl]

Ah I was about to report that I couldn't reproduced what you had 😅

But let me investigate this problem of yours...

[kzc]

Maybe the combined input is just too big. Or perhaps finally we've found a case where the 0 and 1 replacement values are just not diverse enough.

[kzc]

The ill-performing combined test case produces similar but different errors when minified and run:

$ cat irreducible.js | node
...
ReferenceError: K is not defined

$ cat irreducible.js | bin/uglifyjs -mc toplevel | node
...
ReferenceError: J is not defined

I wonder if that has something to do with it.

[alexlamsl]

Indeed - the latest push in #3742 should fix that.