Bug in `cascade` #2107

alexlamsl · 2017-06-15T19:40:50Z

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

function f0(b) {
    {
        var brake1 = 5;
        while ((c = c + 1) + /[abc4]/.test((a++ || b || 5).toString()) && --brake1 > 0) {
            try {
                {
                    var b = function f1() {
                        {
                            var bar = function f2(arguments) {
                                if (c = 1 + c, ((1 ^ NaN) > (undefined && "number")) >>> "number" % Infinity % (38..toString() % -5)) {
                                    c = 1 + c, a && (a.Infinity = ((-3 ^ Infinity) - {} * "foo") % (3 & 4 | ("undefined" || -3)));
                                } else {
                                    c = 1 + c, "function" <= undefined > (a && (a.b += -2 <= undefined)) >= ((c = c + 1, 
                                    22) <= (4 & Infinity));
                                }
                                {
                                }
                            }([ (c = 1 + c, "foo" - ([ , 0 ].length === 2) !== 0 % true ^ (Infinity, 3) % ([] == 4)) ][(c = c + 1) + -a]);
                        }
                        {
                            var parseInt = function f3() {
                                function f4(NaN, bar) {
                                }
                                var b_2 = f4("function", "function");
                            }(--b + (void function() {
                            }() || 1).toString()[(c = c + 1) + (b + 1 - .1 - .1 - .1)]);
                        }
                    }(a++ + new function() {
                        this.NaN = ((("" ^ -2) <= (a && (a.a = undefined == undefined))) >>> ("foo" + -0 === "object" <= 3) === ("number" === []) * (23..toString() <= -5) * (a && (a[a++ + -0] = ("number" & [ , 0 ][1]) + (false === 0)))) >> (~(23..toString() | /[a2][^e]+$/) >> {} % ([ , 0 ].length === 2) % (25 > "object") || (a && (a[[ (c = 1 + c, 
                        (("undefined" ^ "undefined") & ([ , 0 ].length === 2) >>> 3) << (2 >>> 4 !== ({} ^ -1))), (c = 1 + c, 
                        (c = c + 1, "undefined") > (a && (a[(c = 1 + c, 3 - -5 <= (1 ^ "number") ^ void (a && (a[(c = 1 + c, 
                        a && (a.undefined >>= (a && (a.var += (false == "bar", -3 !== 0))) & (false | 24..toString()) === ("undefined" !== -4)))] |= "number" == false)))] += null & "bar")), 
                        5 != 0 != ("function" && [ , 0 ].length === 2)) ]] += ({} | 0) > (2 || "function"))) !== ((a && (a[(c = 1 + c, 
                        (a && (a[b %= a] >>>= 5 !== "undefined" || "foo" % 5)) + ((a && (a[(c = 1 + c, (23..toString() <= "bar") << Infinity % null ^ (3 % {} || 3 * -5))] = -3 >= "undefined")) < /[a2][^e]+$/ / 3))] = undefined && -0)) !== -4 <= []));
                        this.a += (NaN > /[a2][^e]+$/ > (-0 ^ 4) !== ("object" <= 2) - (a && (a.a >>>= -0 >> 1)) ^ (c = c + 1, 
                        c = c + 1, /[a2][^e]+$/ || {})) << ((5 ^ NaN | null > 1) & -3 % -2 != 1 >> "bar") / (2 + "undefined" && void "object" && ("undefined" >= 3) >>> ([ , 0 ].length === 2 & -3));
                        this[{
                            get Infinity() {
                                c = c + 1;
                                {
                                    return b--;
                                }
                            },
                            "": [ , 0 ].length === 2
                        }] /= ((("function" | -5) << ("function", 0) && "number" > "foo" | (25 | "function")) == ("" + null > 38..toString() * "foo") + (NaN & {}) % (a && (a[(c = 1 + c, 
                        ((c = c + 1, true) >= -5 % "object") >> ((2 & "bar") > NaN + "object"))] += "number" % NaN))) >>> (((-3 <= 0) >>> (0, 
                        [ , 0 ][1]) == (null === 25) >>> (-5 & null)) < (38..toString() < 4 < ("function" !== -3) <= ("object" & 25 ^ (22 | 3))));
                        var undefined_2 = void b, bar_1 = (c = c + 1) + [ (c = 1 + c, (/[a2][^e]+$/ || Infinity) * ("function" ^ []) << (5 - undefined != ("function" && NaN))) ].a;
                        return a++ + (typeof bar_1 == "object");
                        {
                            var brake14 = 5;
                            L202814: while ([ (c = 1 + c, bar_1 && (bar_1.foo = ((/[a2][^e]+$/ | 23..toString()) !== (undefined && 3)) >> (38..toString() << 24..toString()) / ([ , 0 ][1], 
                            -3))), (c = 1 + c, "" !== 25 !== (undefined_2 && (undefined_2.null = "" != 25)) !== (undefined_2 = (c = c + 1, 
                            2) >>> (bar_1 && (bar_1.NaN += 3 >= 4)))), (c = 1 + c, (undefined - [] || 38..toString() === ([ , 0 ].length === 2)) < ({} && null) / ([ , 0 ][1] > 4)), (c = 1 + c, 
                            (NaN >>> undefined | "object" & 22) === (Infinity <= "number" ^ (bar_1 && (bar_1[(c = 1 + c, 
                            (-5 != -4) < (23..toString() | 22) !== (1 * 23..toString() && -4 >> /[a2][^e]+$/))] += 22 / undefined)))) ] && --brake14 > 0) {
                                switch ((c = c + 1) + ((c = 1 + c, (2 % 2 ^ ("bar" | null)) < (3 >> "object" <= (c = c + 1, 
                                [ , 0 ].length === 2))) ? (c = 1 + c, Infinity > 0 > "number" / 2 >= +(undefined & null)) : (c = 1 + c, 
                                (undefined << -5 || "" - -2) < (23..toString() !== 2) + delete 5))) {
                                  case /[abc4]/.test(((c = 1 + c, c = c + 1, [ , 0 ][1] > 3 ^ [] >> null) || b || 5).toString()):
                                    break;

                                  case --b + (c = 1 + c, (-5 && Infinity) ^ /[a2][^e]+$/ === 4 ^ ((false, []) ^ [ , 0 ].length === 2 == 2)):
                                    break;

                                  case +a:
                                    c = 1 + c, c = c + 1, -5 >> 22 | (undefined || Infinity);
                                    break;

                                  default:
                                    c = 1 + c, ("object" * 5 < (-2 < -0)) >> ((Infinity == 3) >>> (NaN >> true));
                                }
                            }
                        }
                    }());
                }
            } catch (b) {
                {
                    var brake18 = 5;
                    do {
                        {
                            ({
                                0: (c = 1 + c, (5 >> "object" ^ (a = -0 <= 3)) !== (3 & 4) % ({} === Infinity)),
                                3: (c = 1 + c, ((3 ^ "object") <= (3 | 1)) * (null * "" == (-0 ^ 25))),
                                foo: (c = 1 + c, (a && (a[/[a2][^e]+$/] = "bar" === 38..toString() == (5 && 24..toString()))) / ("object" !== "foo" | true << -5)),
                                length: (c = 1 + c, (2 !== -1) >= (-0 === "foo") & (a && (a[(c = 1 + c, ((-5 === 38..toString()) > NaN + "foo") >> ((4 == Infinity) >>> (1 !== "number")))] = "function" !== 25)) == (false | -2))
                            })[--b];
                            for (var brake21 = 5; typeof b == "string" && brake21 > 0; --brake21) {}
                            {
                                var brake23 = 5;
                                while (--b + (--b + ~b) && --brake23 > 0) {
                                    switch (a++ + +("bar" + "" > [ , 0 ][1] >>> undefined == (5 << 4) % (/[a2][^e]+$/ % 3))) {
                                      case (c = c + 1) + (c = 1 + c, "number" / "object" * ("" ^ "foo") < (a && (a[--b + ((c = 1 + c, 
                                        (-2 | -3 || a && (a.undefined = "" < 25)) % ((-0 >= -4) >> (4 <= {}))) ? (c = 1 + c, 
                                        (2 <= 0) / (3 ^ 0) == ("number" === -0 !== ("function" && "undefined"))) : (c = 1 + c, 
                                        ((a && (a.null %= "bar" > 3)) >>> (a %= undefined >> 4)) + (([ , 0 ].length === 2) >= [] != -0 / 0)))] += (2 | 0) / ("undefined" && "number")))):
                                        c = 1 + c, (a -= "foo" < 25) >>> "function" + 22 == +(false < -1);
                                        c = 1 + c, ([] && 0) + 5 % "undefined" < (-5 <= 5) + (true - "function");
                                        break;

                                      case a++ + --b:
                                        break;

                                      case c = 1 + c, (a && (a.a &= undefined % -1)) << ("function" && 4) == ("number" ^ -0) % ([ , 0 ][1] + 3):
                                        break;

                                      case --b + !((-5 != -2 === (a %= undefined ^ 23..toString())) % (a += (-4 >= -4) * (-4 ^ "undefined"))):
                                        c = 1 + c, (NaN % null & ("object" ^ 0)) / (/[a2][^e]+$/ % 24..toString() <= (/[a2][^e]+$/ < /[a2][^e]+$/));
                                        c = 1 + c, ("undefined" << false) + (38..toString() == 0) && (null >>> undefined) + -3 % NaN;
                                        break;
                                    }
                                }
                            }
                            var a;
                        }
                    } while (--b + !(a && (a.c = ((3, 0) | (c = c + 1, [ , 0 ].length === 2)) >>> (c = c + 1, 
                    a && (a[(c = 1 + c, (-1 >= -3 & (-1 | "foo")) * (4 <= "undefined" ^ (a && (a.NaN += [ , 0 ].length === 2 & 3))))] = [ , 0 ][1] ^ false)))) && --brake18 > 0);
                }
                switch (b -= a) {
                  default:
                    typeof ((c = c + 1) + (b = a));
                    {
                        var brake32 = 5;
                        while ((c = c + 1) + ({
                            c: (c = 1 + c, (c = c + 1, [ , 0 ][1] << 3) === (true !== -3) * (true >>> 2)),
                            undefined: (c = 1 + c, (a && (a.var &= 25 < 1 != (22 || [ , 0 ][1]))) - (("number" === ([ , 0 ].length === 2)) + -4 * -4))
                        }.foo || 9).toString()[a && a.b] && --brake32 > 0) {
                            void ((24..toString() === true) >> (-5 | "bar") << ((1 == true) < 5 % /[a2][^e]+$/));
                        }
                    }

                  case a++ + false:
                    {
                        var brake34 = 5;
                        while (--b + typeof ((c = c + 1) + a--) && --brake34 > 0) {
                            var expr35 = {
                                "": (c = 1 + c, ((38..toString() ^ 25) > undefined % true) * ((arguments_1 && (arguments_1[(c = 1 + c, 
                                (-3 < [] ^ {} >>> [ , 0 ][1]) >= +~38..toString())] = 0 >> Infinity)) >> (arguments_1 && (arguments_1[(c = 1 + c, 
                                (c = c + 1, /[a2][^e]+$/) << ("foo" >= 1) <= (([] | Infinity) <= (-5 & "number")))] += -5 == 3))))
                            };
                            L202815: for (var key35 in expr35) {
                                c = 1 + c;
                                var arguments_1 = expr35[key35];
                                for (var brake36 = 5; (c = c + 1) + -a && brake36 > 0; --brake36) {
                                    switch (c = 1 + c, (3 & "" ^ !undefined) * ([ , 0 ][1] % 0 && (arguments_1 && (arguments_1[(c = 1 + c, 
                                    ((c = c + 1, /[a2][^e]+$/) < (arguments_1 && (arguments_1.var += 1 + false))) + (0 >= ([ , 0 ].length === 2) === (5 || -5)))] /= -3 & undefined)))) {
                                      case c = 1 + c, ([ , 0 ][1] || 2) >= (22 || undefined) && ("number" !== "foo") <= true % 38..toString():
                                        ;
                                        break;

                                      case c = 1 + c, c = c + 1, 1 <= -4 ^ (2 ^ 24..toString()):
                                        ;
                                        break;

                                      default:
                                        ;

                                      case c = 1 + c, arguments_1 && (arguments_1[!a] *= (true | "object") >> (-4 >>> null) === (1 == -1) % (/[a2][^e]+$/ >> "foo")):
                                        ;
                                        break;
                                    }
                                }
                            }
                        }
                    }
                    {
                        var brake38 = 5;
                        L202816: while (a++ + ((Infinity / -5 && 23..toString() >= 4) & (-0 != "" && ("foo" && "object"))) && --brake38 > 0) {
                            ++a;
                        }
                    }
                    break;

                  case (c = c + 1) + (b = a):
                    {
                        var expr40 = a++ + /[abc4]/.test((--b + {
                            NaN: (c = 1 + c, (2 || "object") >> (null >= ([ , 0 ].length === 2)), -5 > 3 <= ("function" ^ -0)),
                            NaN: (c = 1 + c, {} - Infinity === {} + "bar" !== (null && -2) > ("foo" <= 3)),
                            in: (c = 1 + c, (Infinity_2 && (Infinity_2[(c = 1 + c, Infinity + {} != null * -5 ^ (-0 * false | (5 || [ , 0 ][1])))] += 5 > 3)) << (23..toString() << -2) || [] >>> 3 && 25 == /[a2][^e]+$/),
                            1.5: (c = 1 + c, ((true && false) >>> ([] & -2)) + void (NaN, -2)),
                            "\t": (c = 1 + c, c = c + 1, [] + "object" >= -3 - -4)
                        }.b || b || 5).toString());
                        for (var key40 in expr40) {
                            c = 1 + c;
                            var Infinity_2 = expr40[key40];
                            switch ((c = c + 1) + ((b += a) ? 22 : a++ + ((!"bar" && ("foo", -5)) << ((undefined || 1) > (-0 || "function"))))) {
                              case -b:
                                {
                                    var brake42 = 5;
                                    while ((c = 1 + c, "object" === 5 ^ 24..toString() > 0 ^ (/[a2][^e]+$/ > "undefined" && -3 ^ undefined)) && --brake42 > 0) {
                                        c = 1 + c, (Infinity_2 && (Infinity_2.in = -1 !== -0 === 4 << undefined)) !== (Infinity_2 && (Infinity_2.foo = delete true ^ "undefined" <= "undefined"));
                                    }
                                }
                                if (c = 1 + c, ((25 == NaN) >>> ([] && 38..toString())) - (Infinity / -3 > "function" >>> 22)) {
                                    c = 1 + c, arguments_1 && (arguments_1[a++ + [ (c = 1 + c, (5 ^ "number") >> (-0 ^ 1) & "number" % 22 > (2 > 25)), (c = 1 + c, 
                                    (24..toString() !== 1) >>> ("object" >>> [ , 0 ][1]) <= (22 >= -3 < (arguments_1 += "undefined" ^ false))), (c = 1 + c, 
                                    c = c + 1, (Infinity_2 && (Infinity_2.Infinity = "undefined" & "bar")) - -4 * -4), (c = 1 + c, 
                                    arguments_1 && (arguments_1.null += (-3, [ , 0 ][1]) | -5 ^ [] || ({} && 2, -4 << -2))), (c = 1 + c, 
                                    (Infinity_2 = "bar" === -1) < (3 >= 38..toString()), /[a2][^e]+$/ > "foo" ^ -2 % 3) ]] *= (1 >= Infinity) >>> ("object" & []) >> ((Infinity_2 = false & NaN) << (24..toString() === NaN)));
                                } else {
                                    c = 1 + c, c = c + 1, (3 && 38..toString()) ^ ([ , 0 ].length === 2) > -0;
                                }
                                break;

                              case --b + [ (c = 1 + c, ([ , 0 ].length === 2 & null ^ /[a2][^e]+$/ & "bar") >>> (arguments_1 && (arguments_1[--b + --b] += -0 <= 1 & "" >>> -0))) ][(c = c + 1) + ({} >>> "object", 
                                [] >> 24..toString()) / (0 != "number" && [] <= 25)]:
                                {
                                    var brake47 = 5;
                                    while ((c = 1 + c, ("foo", 1) + (23..toString() != false) & ("undefined" || -3) >= 4 >>> "bar") && --brake47 > 0) {
                                        c = 1 + c, (-0 << 4) / (24..toString() | -1) >>> (25 * -4 != ([ , 0 ].length === 2) <= 4);
                                    }
                                }
                                break;

                              case a++:
                                try {
                                    c = 1 + c, c = c + 1, (c = c + 1, 25) === 22 >>> ([ , 0 ].length === 2);
                                } catch (b) {
                                }
                                {
                                    var expr51 = (c = 1 + c, Infinity_2 = (-1 >= 25) % (-5 + Infinity) & (Infinity_2 += [] <= "foo") !== true << 4);
                                    for (var key51 in expr51) {
                                        c = 1 + c;
                                        var undefined_1 = expr51[key51];
                                        c = 1 + c, (null && -2) < (c = c + 1, "object") || (Infinity_2 += "undefined" + 23..toString() >>> 4 - "bar");
                                    }
                                }
                                break;

                              default:
                                for (var brake53 = 5; (c = 1 + c, (undefined * 24..toString() !== "object" + "foo") - ([ , 0 ][1] >> -1 ^ ([ , 0 ][1] ^ [ , 0 ][1]))) && brake53 > 0; --brake53) {
                                    c = 1 + c, (24..toString() + 3 !== ("function" && 24..toString())) * ("foo" << -4 >>> (Infinity_2 = ([], 
                                    "function")));
                                }
                                try {
                                    c = 1 + c, undefined_1 = (!-3 & 38..toString() / "object") !== (Infinity_2 && (Infinity_2.c = NaN !== -0 & "object" != NaN));
                                } finally {
                                }
                            }
                        }
                    }
                    break;

                  case --b + (1 === 1 ? a : b) ? a++ + a++ : delete a:
                    {
                        var brake57 = 5;
                        while (a-- && --brake57 > 0) {
                            try {
                                c = 1 + c, (arguments_1 && (arguments_1[(c = 1 + c, ((3 || "bar") > ("number" === -2)) >> (("number" ^ "function") >= (38..toString() || 24..toString())))] >>>= -0 == "")) < (0 < undefined) && undefined / 23..toString() > (-3 ^ 25);
                            } catch (a_2) {
                            } finally {
                            }
                            c = c + 1;
                            c = 1 + c, (Infinity_2 = (-3, /[a2][^e]+$/)) - (undefined_1 && (undefined_1[(c = 1 + c, 
                            ~((0 !== -2) < {} << 1))] = 5 ^ true)) === ("object" !== -4 & ("bar" & "object"));
                        }
                    }
                    {
                        var expr63 = "object";
                        for (var key63 in expr63) {
                            c = 1 + c;
                            var a_2 = expr63[key63];
                            {
                                var NaN_2 = function f5(b_1) {
                                    c = 1 + c, ({} >= 23..toString(), 2 | -0) % ((NaN !== {}) * (3 < -0));
                                    c = 1 + c, (2 << -2 || (c = c + 1, 22)) >> (b_1 && (b_1[delete (a_2 /= [ , 0 ][1] || -1) === (false << NaN && {} > -1)] ^= 25 ^ [ , 0 ].length === 2 || "" << -0));
                                }(a++ + b--);
                            }
                        }
                    }
                    break;
                }
            }
        }
    }
    if ((arguments_1 && (arguments_1.in = (0 === true) + (4 === undefined))) === (Infinity ^ [ , 0 ][1], 
    "function" > -4)) {
        var brake68 = 5;
        do {
        } while ((0 === 1 ? a : b) && --brake68 > 0);
    }
}

var b = f0();

console.log(null, a, b, c);

// uglified code
// (beautified)
function f0(b) {
    for (var brake1 = 5; (c += 1) + /[abc4]/.test((a++ || b || 5).toString()) && --brake1 > 0; ) {
        try {
            var b = function() {
                (function(arguments) {
                    c = 1 + c, !1 >>> NaN % (38..toString() % -5) ? (c = 1 + c, a && (a.Infinity = (-3 - "foo" * {}) % 0)) : (c = 1 + c, 
                    a && (a.b += !1), c += 1);
                })((c = 1 + c, c += 1)), --b, 1..toString()[(c += 1) + (b + 1 - .1 - .1 - .1)];
            }((a++, new function() {
                this.NaN = ((-2 <= (a && (a.a = !0))) >>> !1 == ("number" === []) * (23..toString() <= -5) * (a && (a[a++ - 0] = ("number" & [ , 0 ][1]) + !1))) >> (~(23..toString() | /[a2][^e]+$/) >> {} % (2 === [ , 0 ].length) % !1 || (a && (a[[ (c = 1 + c, 
                (0 & (2 === [ , 0 ].length) >>> 3) << (0 != (-1 ^ {}))), (c = 1 + c, c += 1, a && (a[(c = 1 + c, 
                !1 ^ void (a && (a[(c = 1 + c, a && (a.undefined >>= (a && (a.var += !0)) & !0 === (!1 | 24..toString())))] |= !1)))] += 0), 
                1 != (2 === [ , 0 ].length)) ]] += (0 | {}) > 2)) !== ((a && (a[(c = 1 + c, (a && (a[b %= a] >>>= !0)) + ((a && (a[(c = 1 + c, 
                (23..toString() <= "bar") << NaN ^ (3 % {} || -15))] = !1)) < NaN))] = void 0)) !== -4 <= [])), 
                this.a += (!1 !== !1 - (a && (a.a >>>= 0)) ^ (c += 1, c += 1, /[a2][^e]+$/)) << NaN, 
                this[{
                    get Infinity() {
                        return c += 1, b--;
                    },
                    "": 2 === [ , 0 ].length
                }] /= (25 == ("null" > "foo" * 38..toString()) + (NaN & {}) % (a && (a[(c = 1 + c, 
                c += 1, 0)] += NaN))) >>> ((!0 >>> [ , 0 ][1] == 0) < (38..toString() < 4 < !0 <= 23));
                c += 1, c = 1 + (c += 1);
                a++;
            }()));
        } catch (b) {
            var brake18 = 5;
            do {
                c = 1 + (c = 1 + (c = 1 + c)), (a = !0) && (a[/[a2][^e]+$/] = "bar" === 38..toString() == 24..toString()), 
                c = 1 + c, a && (a[(c = 1 + c, ((-5 === 38..toString()) > "NaNfoo") >> 0)] = !0), 
                --b;
                for (var brake21 = 5; "string" == typeof b && brake21 > 0; --brake21) {}
                for (var brake23 = 5; --b + (--b + ~b) && --brake23 > 0; ) {
                    switch (a++ + +("bar" > [ , 0 ][1] >>> void 0 == NaN)) {
                      case (c += 1) + (c = 1 + c, NaN < (a && (a[--b + (c = 1 + c, -1 % (!0 >> (4 <= {})) ? (c = 1 + c, 
                        !1) : (c = 1 + c, ((a && (a.null %= !1)) >>> (a %= 0)) + ((2 === [ , 0 ].length) >= [] != NaN)))] += NaN))):
                        a -= !1, c = 1 + (c = 1 + c);
                        break;

                      case a++ + --b:
                      case c = 1 + c, (a && (a.a &= NaN)) << 4 == 0 % ([ , 0 ][1] + 3):
                        break;

                      case --b + !((!0 === (a %= void 0 ^ 23..toString())) % (a += -4)):
                        c = 1 + c, 24..toString(), c = 1 + c, 38..toString();
                    }
                }
                var a;
            } while (--b + !(a && (a.c = (0 | (c += 1, 2 === [ , 0 ].length)) >>> (c += 1, a && (a[(c = 1 + c, 
            1 * (!1 ^ (a && (a.NaN += 2 === [ , 0 ].length & 3))))] = !1 ^ [ , 0 ][1])))) && --brake18 > 0);
            switch (b -= a) {
              default:
                c += 1, b = a;
                for (var brake32 = 5; (c += 1) + ({
                    c: (c = 1 + c, 0 == (c += 1, [ , 0 ][1] << 3)),
                    undefined: (c = 1 + c, (a && (a.var &= !0)) - (("number" === (2 === [ , 0 ].length)) + 16))
                }.foo || 9).toString()[a && a.b] && --brake32 > 0; ) {
                    24..toString();
                }

              case a++ + !1:
                for (var brake34 = 5; --b + typeof ((c += 1) + a--) && --brake34 > 0; ) {
                    var expr35 = {
                        "": (c = 1 + c, ((25 ^ 38..toString()) > NaN) * ((arguments_1 && (arguments_1[(c = 1 + c, 
                        (-3 < [] ^ {} >>> [ , 0 ][1]) >= +~38..toString())] = 0)) >> (arguments_1 && (arguments_1[(c = 1 + c, 
                        c += 1, 0 <= (([] | 1 / 0) <= 0))] += !1))))
                    };
                    for (var key35 in expr35) {
                        c = 1 + c;
                        for (var arguments_1 = expr35[key35], brake36 = 5; (c += 1) + -a && brake36 > 0; --brake36) {
                            switch (c = 1 + c, 1 * ([ , 0 ][1] % 0 && arguments_1 && (arguments_1[(c = 1 + c, 
                            c += 1, (/[a2][^e]+$/ < (arguments_1 && (arguments_1.var += 1))) + (0 >= (2 === [ , 0 ].length) === 5))] /= 0))) {
                              case c = 1 + c, ([ , 0 ][1] || 2) >= 22 && !0 <= !0 % 38..toString():
                              case c = 1 + c, c += 1, 2 ^ 24..toString():
                                break;

                              default:
                              case c = 1 + c, arguments_1 && (arguments_1[!a] *= !1):
                            }
                        }
                    }
                }
                for (var brake38 = 5; a++ + (23..toString() >= 4 & !1) && --brake38 > 0; ) {
                    ++a;
                }
                break;

              case (c += 1) + (b = a):
                var expr40 = a++ + /[abc4]/.test((--b + {
                    NaN: (c = 1 + c, !0),
                    NaN: (c = 1 + c, {} - 1 / 0 === {} + "bar" != !1),
                    in: (c = 1 + c, (Infinity_2 && (Infinity_2[(c = 1 + c, 1 / 0 + {} != -0 ^ 5)] += !0)) << (23..toString() << -2) || [] >>> 3 && !1),
                    1.5: (c = 1 + c, (!1 >>> (-2 & [])) + void 0),
                    "\t": (c = 1 + c, c += 1, [] + "object" >= 1)
                }.b || b || 5).toString());
                for (var key40 in expr40) {
                    c = 1 + c;
                    var Infinity_2 = expr40[key40];
                    switch ((c += 1) + ((b += a) ? 22 : 0 + a++)) {
                      case -b:
                        for (var brake42 = 5; c = 1 + c, !1 ^ 24..toString() > 0 ^ !1 && --brake42 > 0; ) {
                            c = 1 + c, Infinity_2 && (Infinity_2.in = !1), Infinity_2 && (Infinity_2.foo = 0);
                        }
                        c = 1 + c, (!1 >>> ([] && 38..toString())) - !1 ? (c = 1 + c, arguments_1 && (arguments_1[a++ + [ (c = 1 + c, 
                        0), (c = 1 + c, (1 !== 24..toString()) >>> ("object" >>> [ , 0 ][1]) <= (!0 < (arguments_1 += 0))), (c = 1 + c, 
                        c += 1, (Infinity_2 && (Infinity_2.Infinity = 0)) - 16), (c = 1 + c, arguments_1 && (arguments_1.null += [ , 0 ][1] | -5 ^ [] || 0)), (c = 1 + c, 
                        Infinity_2 = !1, 38..toString(), -2) ]] *= !1 >>> ("object" & []) >> ((Infinity_2 = 0) << (NaN === 24..toString())))) : (c = 1 + c, 
                        c += 1, 38..toString());
                        break;

                      case --b + [ (c = 1 + c, (2 === [ , 0 ].length & null ^ 0) >>> (arguments_1 && (arguments_1[--b + --b] += 0))) ][(c += 1) + ([] >> 24..toString()) / ([] <= 25)]:
                        for (var brake47 = 5; c = 1 + c, 1 + (0 != 23..toString()) & !1 && --brake47 > 0; ) {
                            c = 1 + c, 24..toString();
                        }
                        break;

                      case a++:
                        try {
                            c = 1 + c, c += 1, c += 1;
                        } catch (b) {}
                        var expr51 = (c = 1 + c, Infinity_2 = 0 & 16 !== (Infinity_2 += [] <= "foo"));
                        for (var key51 in expr51) {
                            c = 1 + c;
                            var undefined_1 = expr51[key51];
                            c = 1 + c, null < (c += 1, "object") || (Infinity_2 += "undefined" + 23..toString() >>> NaN);
                        }
                        break;

                      default:
                        for (var brake53 = 5; c = 1 + c, (void 0 * 24..toString() !== "objectfoo") - ([ , 0 ][1] >> -1 ^ [ , 0 ][1] ^ [ , 0 ][1]) && brake53 > 0; --brake53) {
                            c = 1 + c, 24..toString(), 24..toString(), Infinity_2 = "function";
                        }
                        try {
                            c = 1 + c, undefined_1 = (!1 & 38..toString() / "object") !== (Infinity_2 && (Infinity_2.c = 1));
                        } finally {}
                    }
                }
                break;

              case --b + a ? a++ + a++ : delete a:
                for (var brake57 = 5; a-- && --brake57 > 0; ) {
                    try {
                        c = 1 + c, (arguments_1 && (arguments_1[(c = 1 + c, !0 >> (0 >= (38..toString() || 24..toString())))] >>>= !0)) < !1 && 23..toString();
                    } catch (a_2) {}
                    c = 1 + (c += 1), Infinity_2 = /[a2][^e]+$/, undefined_1 && (undefined_1[(c = 1 + c, 
                    ~(!0 < {} << 1))] = 4);
                }
                for (var key63 in "object") {
                    c = 1 + c;
                    var a_2 = "object"[key63];
                    (function(b_1) {
                        c = 1 + c, 23..toString(), c = 1 + c, b_1 && (b_1[0 === (a_2 /= [ , 0 ][1] || -1, 
                        !0)] ^= 25 ^ 2 === [ , 0 ].length || 0);
                    })(a++ + b--);
                }
            }
        }
    }
    if (!1 === (arguments_1 && (arguments_1.in = 0))) {
        var brake68 = 5;
        do {} while (b && --brake68 > 0);
    }
}

var a = 100, b = 10, c = 0, b = f0();

console.log(null, a, b, c);

original result:
null 100 undefined 45

uglified result:
null 100 undefined 49

minify(options):
{
  "mangle": false
}

Suspicious compress options:
  cascade
  collapse_vars
  dead_code
  inline
  join_vars
  sequences
  side_effects
  unused

alexlamsl · 2017-06-15T19:44:39Z

So far narrowed down to:

var a = 100, b = 10, c = 0;

function f0(b) {
    var b = function f1() {
        {
            var bar = function f2(arguments) {
                if (c = 1 + c, ((1 ^ NaN) > (undefined && "number")) >>> "number" % Infinity % (38..toString() % -5)) {
                    c = 1 + c, a && (a.Infinity = ((-3 ^ Infinity) - {} * "foo") % (3 & 4 | ("undefined" || -3)));
                }
            }([ (c = 1 + c, "foo" - ([ , 0 ].length === 2) !== 0 % true ^ (Infinity, 3) % ([] == 4)) ][(c = c + 1) + -a]);
        }
    }(a++ + new function() {
        this.NaN = ((("" ^ -2) <= (a && (a.a = undefined == undefined))) >>> ("foo" + -0 === "object" <= 3) === ("number" === []) * (23..toString() <= -5) * (a && (a[a++ + -0] = ("number" & [ , 0 ][1]) + (false === 0)))) >> (~(23..toString() | /[a2][^e]+$/) >> {} % ([ , 0 ].length === 2) % (25 > "object") || (a && (a[[ (c = 1 + c,
        (("undefined" ^ "undefined") & ([ , 0 ].length === 2) >>> 3) << (2 >>> 4 !== ({} ^ -1))), (c = 1 + c,
        (c = c + 1, "undefined") > (a && (a[(c = 1 + c, 3 - -5 <= (1 ^ "number") ^ void (a && (a[(c = 1 + c,
        a && (a.undefined >>= (a && (a.var += (false == "bar", -3 !== 0))) & (false | 24..toString()) === ("undefined" !== -4)))] |= "number" == false)))] += null & "bar")),
        5 != 0 != ("function" && [ , 0 ].length === 2)) ]] += ({} | 0) > (2 || "function"))) !== ((a && (a[(c = 1 + c,
        (a && (a[b %= a] >>>= 5 !== "undefined" || "foo" % 5)) + ((a && (a[(c = 1 + c, (23..toString() <= "bar") << Infinity % null ^ (3 % {} || 3 * -5))] = -3 >= "undefined")) < /[a2][^e]+$/ / 3))] = undefined && -0)) !== -4 <= []));
        this.a += (NaN > /[a2][^e]+$/ > (-0 ^ 4) !== ("object" <= 2) - (a && (a.a >>>= -0 >> 1)) ^ (c = c + 1,
        c = c + 1, /[a2][^e]+$/ || {})) << ((5 ^ NaN | null > 1) & -3 % -2 != 1 >> "bar") / (2 + "undefined" && void "object" && ("undefined" >= 3) >>> ([ , 0 ].length === 2 & -3));
        var undefined_2 = void b, bar_1 = (c = c + 1) + [ (c = 1 + c, (/[a2][^e]+$/ || Infinity) * ("function" ^ []) << (5 - undefined != ("function" && NaN))) ].a;
        return a++ + (typeof bar_1 == "object");
    }());
}

var b = f0();

console.log(null, a, b, c);

$ uglifyjs test.js -b bracketize -c cascade=0 -o good.js
$ uglifyjs test.js -b bracketize -c cascade=1 -o bad.js
$ cat test.js | node
null 103 undefined 7
$ cat good.js | node
null 103 undefined 7
$ cat bad.js | node
null 103 undefined 8

--- a/good.js
+++ b/bad.js
@@ -10,7 +10,7 @@ function f0(b) {
         1 != (2 === [ , 0 ].length)) ]] += (0 | {}) > 2)) !== ((a && (a[(c = 1 + c, (a && (a[b %= a] >>>= !0)) + ((a && (a[(c = 1 + c,
         (23..toString() <= "bar") << NaN ^ (3 % {} || -15))] = !1)) < NaN))] = void 0)) !== -4 <= [])),
         this.a += (!1 !== !1 - (a && (a.a >>>= 0)) ^ (c += 1, c += 1, /[a2][^e]+$/)) << NaN;
-        var bar_1 = (c += 1) + [ (c = 1 + c, /[a2][^e]+$/ * ("function" ^ []) << !0) ].a;
+        c += 1, c = 1 + (c += 1);
         a++;
     }()));
 }

OT: off for a nap 💤

alexlamsl · 2017-06-16T04:13:03Z

This seems to be the bare minimum - and it looks like collapse_vars is at fault instead:

var c = 0;

!function() {
    c++;
}(c++ + new function() {
    this.NaN = 0;
    var bar_1 = (c = c + 1) + (c = 1 + c);
    return c++ + bar_1;
}());

console.log(c);

kzc · 2017-06-16T04:28:38Z

The regression is pretty recent:

$ cat 2107.js | node
5

$ git checkout v3.0.16
HEAD is now at 4231f73... v3.0.16
$ cat 2107.js | bin/uglifyjs -c | node
5

$ git checkout v3.0.17
HEAD is now at 57dc4fb... v3.0.17
$ cat 2107.js | bin/uglifyjs -c | node
6

kzc · 2017-06-16T04:32:13Z

Regression introduced in b85a358

kzc · 2017-06-16T04:36:14Z

looks like collapse_vars is at fault instead

I think cascade remains the underlying cause:

$ cat 2107.js | node
5

$ cat 2107.js | bin/uglifyjs -c cascade=0,reduce_vars=0,collapse_vars=1 | node
5

$ cat 2107.js | bin/uglifyjs -c cascade=1,reduce_vars=0,collapse_vars=1 | node
6

kzc · 2017-06-16T04:46:06Z

I think any changes to lib/*.js would benefit from 1M iterations of test/ufuzz.js before release. The compress code in particular is a fairly complex to say the least.

alexlamsl · 2017-06-16T05:27:39Z

I think any changes to lib/*.js would benefit from 1M iterations of test/ufuzz.js before release.

There were >1MFuzz in between those releases, mind you 😅

alexlamsl · 2017-06-16T05:28:45Z

Regression introduced in b85a358

Interesting - that commit doesn't look related to the test code. Thanks for the information anyway 👍

kzc · 2017-06-16T05:32:01Z

There were >1MFuzz in between those releases, mind you

My apologies and 👍 .

alexlamsl · 2017-06-16T05:35:41Z

I think the general phenomema is that inline is now shaking out a lot of potential bugs in the existing code. Though a lot of them seems to be related to AST node cloning, which are somewhat hard to nail as they are very delicately linked to runtime performance.

kzc · 2017-06-16T05:41:55Z

That makes sense.

In fairness, I did not anticipate function cloning when I wrote collapse_vars. The algorithm depended on the fact that it was replacing single-use variables and just stealing the AST value from the declaration definition as there was no chance of sharing the variable value at the time - the variable reference count must be exactly 1. I suppose the definition value could always be deep cloned when collapsed, but performance could take a hit.

kzc · 2017-06-16T05:45:22Z

that commit doesn't look related to the test code.

That's why it's so curious that it affects it. You can double check it yourself.

kzc · 2017-06-16T05:48:12Z

there was no chance of sharing the variable value at the time - the variable reference count must be exactly 1.

When a function is deep cloned are variable definition references updated accordingly?

alexlamsl · 2017-06-16T05:57:50Z

That's why it's so curious that it affects it. You can double check it yourself.

It's due to this.NaN = 0; in #2107 (comment) suppressing the inlining, which in turn exposes a multiple reference issue in the AST, i.e. two instance of (c = c + 1), (c = 1 + c) share the same instance of (c = 1 + c), so when one gets optimised into c = 1 + (c += 1), the other instance got corrupted.

The inline suppression is also incorrect, but that would only produce sub-optimal rather than invalid output.

alexlamsl · 2017-06-16T05:59:09Z

When a function is deep cloned are variable definition references updated accordingly?

Only label references are updated at the moment.

kzc · 2017-06-16T06:00:17Z

I think collapse_vars' assumption of dealing with variable definitions with ref counts of exactly 1 still holds true - does it not?

alexlamsl · 2017-06-16T06:03:46Z

I think collapse_vars' assumption of dealing with variable definitions with ref counts of exactly 1 still holds true - does it not?

It does.

kzc · 2017-06-16T06:10:20Z

It's due to this.NaN = 0; in #2107 (comment) suppressing the inlining, which in turn exposes a multiple reference issue in the AST, i.e. two instance of (c = c + 1), (c = 1 + c) share the same instance of (c = 1 + c), so when one gets optimised into c = 1 + (c += 1), the other instance got corrupted.

Trying to understand the issue - is a function clone taking place - and the clone is modified - even though the clone is not ultimately used?

fixes mishoo#2107

alexlamsl · 2017-06-16T06:24:55Z

Trying to understand the issue - is a function clone taking place - and the clone is modified - even though the clone is not ultimately used?

Yup - and the clone went through optimisation separately before being discarded.

OT: sorry for the late replies - GitHub notification seems to be malfunctioning for the past couple of days.

kzc · 2017-06-16T06:36:42Z

Yup - and the clone went through optimisation separately before being discarded.

Is this a best_of sort of situation?

alexlamsl · 2017-06-16T06:49:20Z

Is this a best_of sort of situation?

Bingo! 😉
https://github.com/mishoo/UglifyJS2/blob/33405bb24b9a5933badf146a9576953b8b456aad/lib/compress.js#L3222

fixes #2107

alexlamsl added the bug label Jun 15, 2017

alexlamsl added a commit to alexlamsl/UglifyJS that referenced this issue Jun 16, 2017

correctly determine scope of AST_This

b068579

fixes mishoo#2107

alexlamsl mentioned this issue Jun 16, 2017

correctly determine scope of AST_This #2109

Merged

alexlamsl closed this as completed in #2109 Jun 16, 2017

alexlamsl added a commit that referenced this issue Jun 16, 2017

correctly determine scope of AST_This (#2109)

11e63bc

fixes #2107

alexlamsl mentioned this issue Jun 16, 2017

Bug triggered by keep_fargs=false #2114

Closed

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Bug in cascade #2107

Bug in cascade #2107

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Bug in `cascade` #2107

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