From 2b6657e96749989b55f0d98b00683016a1fccea1 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Mon, 15 Jan 2018 04:56:06 +0800
Subject: [PATCH 01/28] run `test/ufuzz.js` when Travis CI is idle (#2784)

---
 test/travis-ufuzz.js | 45 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 test/travis-ufuzz.js

diff --git a/test/travis-ufuzz.js b/test/travis-ufuzz.js
new file mode 100644
index 00000000..2fbe3b00
--- /dev/null
+++ b/test/travis-ufuzz.js
@@ -0,0 +1,45 @@
+"use strict";
+
+var period = 20 * 60 * 1000;
+if (process.argv.length > 2) {
+    var token = process.argv[2];
+    var branch = process.argv[3] || "v" + require("../package.json").version;
+    (function init() {
+        setTimeout(init, period);
+        var options = require("url").parse("https://api.travis-ci.org/repo/mishoo%2FUglifyJS2/requests");
+        options.method = "POST";
+        options.headers = {
+            "Content-Type": "application/json",
+            "Travis-API-Version": 3,
+            "Authorization": "token " + token
+        };
+        require("https").request(options, function(res) {
+            console.log("HTTP", res.statusCode);
+            console.log(JSON.stringify(res.headers, null, 2));
+            console.log();
+            res.setEncoding("utf8");
+            res.on("data", console.log);
+        }).on("error", console.error).end(JSON.stringify({
+            request: {
+                message: "ufuzz testing (when idle)",
+                branch: branch,
+                config: {
+                    merge_mode: "replace",
+                    language: "node_js",
+                    node_js: "9",
+                    sudo: false,
+                    script: "node test/travis-ufuzz"
+                }
+            }
+        }));
+    })();
+} else {
+    var child = require("child_process").spawn("node", [ "test/ufuzz" ], {
+        stdio: [ "ignore", "ignore", 1 ]
+    });
+    var keepAlive = setInterval(console.log, 5 * 60 * 1000);
+    setTimeout(function() {
+        clearInterval(keepAlive);
+        child.kill();
+    }, period);
+}

From f96929c0313529dbf323ba20f7dc1be0f0e4e3ba Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Mon, 15 Jan 2018 15:08:35 +0800
Subject: [PATCH 02/28] improve `test/travis-ufuzz.js` (#2786)

- use more RAM
- show progress in console
- report failure as job status
---
 test/travis-ufuzz.js | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/test/travis-ufuzz.js b/test/travis-ufuzz.js
index 2fbe3b00..0ed76823 100644
--- a/test/travis-ufuzz.js
+++ b/test/travis-ufuzz.js
@@ -34,10 +34,24 @@ if (process.argv.length > 2) {
         }));
     })();
 } else {
-    var child = require("child_process").spawn("node", [ "test/ufuzz" ], {
-        stdio: [ "ignore", "ignore", 1 ]
+    var child = require("child_process").spawn("node", [
+        "--max-old-space-size=2048",
+        "test/ufuzz"
+    ], {
+        stdio: [ "ignore", "pipe", "pipe" ]
     });
-    var keepAlive = setInterval(console.log, 5 * 60 * 1000);
+    var line = "";
+    child.stdout.on("data", function(data) {
+        line += data;
+    });
+    child.stderr.on("data", function() {
+        process.exitCode = (process.exitCode || 0) + 1;
+    }).pipe(process.stdout);
+    var keepAlive = setInterval(function() {
+        var end = line.lastIndexOf("\r");
+        console.log(line.slice(line.lastIndexOf("\r", end - 1) + 1, end));
+        line = line.slice(end + 1);
+    }, 5 * 60 * 1000);
     setTimeout(function() {
         clearInterval(keepAlive);
         child.kill();

From cbbe6fad60dd073c63575f591d631efa94bbceaf Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Mon, 15 Jan 2018 16:42:15 +0800
Subject: [PATCH 03/28] avoid double counting within single-use functions
 (#2785)

fixes #2783
---
 lib/compress.js            |  1 +
 test/compress/functions.js | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/lib/compress.js b/lib/compress.js
index 321a1340..7e3503fe 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -5022,6 +5022,7 @@ merge(Compressor.prototype, {
             }
             if (single_use && fixed) {
                 if (fixed instanceof AST_Defun) {
+                    fixed._squeezed = true;
                     fixed = make_node(AST_Function, fixed, fixed);
                 }
                 var value;
diff --git a/test/compress/functions.js b/test/compress/functions.js
index 222aa0ca..2d55dd52 100644
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -1951,3 +1951,41 @@ issue_2737_2: {
     }
     expect_stdout: "PASS"
 }
+
+issue_2783: {
+    options = {
+        collapse_vars: true,
+        conditionals: true,
+        if_return: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            return g;
+            function f(a) {
+                var b = a.b;
+                if (b) return b;
+                return a;
+            }
+            function g(o, i) {
+                while (i--) {
+                    console.log(f(o));
+                }
+            }
+        })()({ b: "PASS" }, 1);
+    }
+    expect: {
+        (function() {
+            return function(o,i) {
+                while (i--) console.log(f(o));
+            };
+            function f(a) {
+                var b = a.b;
+                return b || a;
+            }
+        })()({ b: "PASS" },1);
+    }
+    expect_stdout: "PASS"
+}

From b483678ca7f5e539cef9c57324ecc92d65800f7d Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Mon, 15 Jan 2018 16:42:31 +0800
Subject: [PATCH 04/28] avoid suboptimal termination in `passes` (#2787)

---
 lib/compress.js | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index 7e3503fe..a461cb06 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -171,7 +171,8 @@ merge(Compressor.prototype, {
             node.process_expression(true);
         }
         var passes = +this.options.passes || 1;
-        var last_count = 1 / 0;
+        var min_count = 1 / 0;
+        var stopping = false;
         var mangle = { ie8: this.option("ie8") };
         for (var pass = 0; pass < passes; pass++) {
             node.figure_out_scope(mangle);
@@ -183,9 +184,15 @@ merge(Compressor.prototype, {
                 node.walk(new TreeWalker(function() {
                     count++;
                 }));
-                this.info("pass " + pass + ": last_count: " + last_count + ", count: " + count);
-                if (count >= last_count) break;
-                last_count = count;
+                this.info("pass " + pass + ": last_count: " + min_count + ", count: " + count);
+                if (count < min_count) {
+                    min_count = count;
+                    stopping = false;
+                } else if (stopping) {
+                    break;
+                } else {
+                    stopping = true;
+                }
             }
         }
         if (this.option("expression")) {

From 10f961c27b0db61c3a197f8f88080d9197361ea4 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Mon, 15 Jan 2018 18:47:23 +0800
Subject: [PATCH 05/28] enhance `collapse_vars` (#2788)

---
 lib/compress.js                | 14 ++++++++++
 test/compress/collapse_vars.js | 50 ++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/lib/compress.js b/lib/compress.js
index a461cb06..fb1c2fdb 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1181,14 +1181,26 @@ merge(Compressor.prototype, {
                     expr.definitions.forEach(extract_candidates);
                 } else if (expr instanceof AST_DWLoop) {
                     extract_candidates(expr.condition);
+                    if (!(expr.body instanceof AST_Block)) {
+                        extract_candidates(expr.body);
+                    }
                 } else if (expr instanceof AST_Exit) {
                     if (expr.value) extract_candidates(expr.value);
                 } else if (expr instanceof AST_For) {
                     if (expr.init) extract_candidates(expr.init);
                     if (expr.condition) extract_candidates(expr.condition);
                     if (expr.step) extract_candidates(expr.step);
+                    if (!(expr.body instanceof AST_Block)) {
+                        extract_candidates(expr.body);
+                    }
                 } else if (expr instanceof AST_If) {
                     extract_candidates(expr.condition);
+                    if (!(expr.body instanceof AST_Block)) {
+                        extract_candidates(expr.body);
+                    }
+                    if (expr.alternative && !(expr.alternative instanceof AST_Block)) {
+                        extract_candidates(expr.alternative);
+                    }
                 } else if (expr instanceof AST_Sequence) {
                     expr.expressions.forEach(extract_candidates);
                 } else if (expr instanceof AST_SimpleStatement) {
@@ -1215,10 +1227,12 @@ merge(Compressor.prototype, {
                 if (parent instanceof AST_Call) return node;
                 if (parent instanceof AST_Case) return node;
                 if (parent instanceof AST_Conditional) return node;
+                if (parent instanceof AST_Definitions) return find_stop(parent, level + 1);
                 if (parent instanceof AST_Exit) return node;
                 if (parent instanceof AST_If) return node;
                 if (parent instanceof AST_IterationStatement) return node;
                 if (parent instanceof AST_Sequence) return find_stop(parent, level + 1);
+                if (parent instanceof AST_SimpleStatement) return find_stop(parent, level + 1);
                 if (parent instanceof AST_Switch) return node;
                 if (parent instanceof AST_VarDef) return node;
                 return null;
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index 12b49230..f252a7f4 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -4012,3 +4012,53 @@ replace_all_var: {
     }
     expect_stdout: "PASS"
 }
+
+cascade_statement: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        function f1(a, b) {
+            var c;
+            if (a)
+                return c = b, c || a;
+            else
+                c = a, c(b);
+        }
+        function f2(a, b) {
+            var c;
+            while (a)
+                c = b, a = c + b;
+            do
+                throw c = a + b, c;
+            while (c);
+        }
+        function f3(a, b) {
+            for (; a < b; a++)
+                if (c = a, c && b)
+                    var c = (c = b(a), c);
+        }
+    }
+    expect: {
+        function f1(a, b) {
+            var c;
+            if (a)
+                return (c = b) || a;
+            else
+                (c = a)(b);
+        }
+        function f2(a, b) {
+            var c;
+            while (a)
+                a = (c = b) + b;
+            do
+                throw c = a + b;
+            while (c);
+        }
+        function f3(a, b) {
+            for (; a < b; a++)
+                if ((c = a) && b)
+                    var c = c = b(a);
+        }
+    }
+}

From 7def684730ad3a684e64963961f3b33b308fd95d Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Mon, 15 Jan 2018 19:18:21 +0800
Subject: [PATCH 06/28] improve `test/travis-ufuzz.js` (#2789)

- wait for instance to boot
- run on forked repositories
- workaround `request_limit_reached`
---
 test/travis-ufuzz.js | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/test/travis-ufuzz.js b/test/travis-ufuzz.js
index 0ed76823..8685732f 100644
--- a/test/travis-ufuzz.js
+++ b/test/travis-ufuzz.js
@@ -1,12 +1,15 @@
 "use strict";
 
-var period = 20 * 60 * 1000;
+var period = 45 * 60 * 1000;
+var wait = 2 * 60 * 1000;
+var ping = 5 * 60 * 1000;
 if (process.argv.length > 2) {
     var token = process.argv[2];
     var branch = process.argv[3] || "v" + require("../package.json").version;
+    var project = encodeURIComponent(process.argv[4] || "mishoo/UglifyJS2");
     (function init() {
-        setTimeout(init, period);
-        var options = require("url").parse("https://api.travis-ci.org/repo/mishoo%2FUglifyJS2/requests");
+        setTimeout(init, period + wait);
+        var options = require("url").parse("https://api.travis-ci.org/repo/" + project + "/requests");
         options.method = "POST";
         options.headers = {
             "Content-Type": "application/json",
@@ -51,7 +54,7 @@ if (process.argv.length > 2) {
         var end = line.lastIndexOf("\r");
         console.log(line.slice(line.lastIndexOf("\r", end - 1) + 1, end));
         line = line.slice(end + 1);
-    }, 5 * 60 * 1000);
+    }, ping);
     setTimeout(function() {
         clearInterval(keepAlive);
         child.kill();

From ec7cd1dcf7c7a3b86288061b61ad72ba081f83bb Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Mon, 15 Jan 2018 23:41:39 +0800
Subject: [PATCH 07/28] handle VM failure gracefully (#2791)

---
 test/travis-ufuzz.js | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/test/travis-ufuzz.js b/test/travis-ufuzz.js
index 8685732f..579b7448 100644
--- a/test/travis-ufuzz.js
+++ b/test/travis-ufuzz.js
@@ -42,21 +42,26 @@ if (process.argv.length > 2) {
         "test/ufuzz"
     ], {
         stdio: [ "ignore", "pipe", "pipe" ]
+    }).on("exit", function() {
+        console.log(line);
+        clearInterval(keepAlive);
+        clearTimeout(timer);
     });
     var line = "";
     child.stdout.on("data", function(data) {
         line += data;
     });
     child.stderr.on("data", function() {
-        process.exitCode = (process.exitCode || 0) + 1;
+        process.exitCode = 1;
     }).pipe(process.stdout);
     var keepAlive = setInterval(function() {
         var end = line.lastIndexOf("\r");
         console.log(line.slice(line.lastIndexOf("\r", end - 1) + 1, end));
         line = line.slice(end + 1);
     }, ping);
-    setTimeout(function() {
+    var timer = setTimeout(function() {
         clearInterval(keepAlive);
+        child.removeAllListeners("exit");
         child.kill();
     }, period);
 }

From 424173d311cd9c35a10a276abdab1de902158ac2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=ABl=20Galeran?= <Jolg42@users.noreply.github.com>
Date: Tue, 16 Jan 2018 03:29:38 +0100
Subject: [PATCH 08/28] fix typo in README (#2792)

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index d7c47d72..df90d1ca 100644
--- a/README.md
+++ b/README.md
@@ -70,7 +70,7 @@ a double dash to prevent input files being used as option arguments:
                                 `debug`  Add debug prefix and suffix.
                                 `domprops`  Mangle property names that overlaps
                                             with DOM properties.
-                                `keep_quoted`  Only mangle unquoted properies.
+                                `keep_quoted`  Only mangle unquoted properties.
                                 `regex`  Only mangle matched property names.
                                 `reserved`  List of names that should not be mangled.
     -b, --beautify [options]    Beautify output/specify output options:

From b4aef753e7f65c0919c6c40b2b28d9f149bc81ed Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Tue, 16 Jan 2018 17:03:12 +0800
Subject: [PATCH 09/28] general improvements around `AST_ForIn` (#2796)

- compress using `collapse_vars`
- remove unused `name`
- simplify `loop_body`
---
 lib/ast.js                     |  3 +--
 lib/compress.js                | 10 +++++++---
 lib/parse.js                   |  2 --
 test/compress/collapse_vars.js | 27 +++++++++++++++++++++++++++
 4 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/lib/ast.js b/lib/ast.js
index 65918675..4e41659c 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -267,11 +267,10 @@ var AST_For = DEFNODE("For", "init condition step", {
     }
 }, AST_IterationStatement);
 
-var AST_ForIn = DEFNODE("ForIn", "init name object", {
+var AST_ForIn = DEFNODE("ForIn", "init object", {
     $documentation: "A `for ... in` statement",
     $propdoc: {
         init: "[AST_Node] the `for/in` initialization code",
-        name: "[AST_SymbolRef?] the loop variable, only if `init` is AST_Var",
         object: "[AST_Node] the object that we're looping through"
     },
     _walk: function(visitor) {
diff --git a/lib/compress.js b/lib/compress.js
index fb1c2fdb..cd5651a2 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -847,9 +847,8 @@ merge(Compressor.prototype, {
     };
 
     function loop_body(x) {
-        if (x instanceof AST_Switch) return x;
-        if (x instanceof AST_For || x instanceof AST_ForIn || x instanceof AST_DWLoop) {
-            return (x.body instanceof AST_BlockStatement ? x.body : x);
+        if (x instanceof AST_IterationStatement) {
+            return x.body instanceof AST_BlockStatement ? x.body : x;
         }
         return x;
     };
@@ -1193,6 +1192,11 @@ merge(Compressor.prototype, {
                     if (!(expr.body instanceof AST_Block)) {
                         extract_candidates(expr.body);
                     }
+                } else if (expr instanceof AST_ForIn) {
+                    extract_candidates(expr.object);
+                    if (!(expr.body instanceof AST_Block)) {
+                        extract_candidates(expr.body);
+                    }
                 } else if (expr instanceof AST_If) {
                     extract_candidates(expr.condition);
                     if (!(expr.body instanceof AST_Block)) {
diff --git a/lib/parse.js b/lib/parse.js
index 001587bc..eba833dc 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -1054,12 +1054,10 @@ function parse($TEXT, options) {
     };
 
     function for_in(init) {
-        var lhs = init instanceof AST_Var ? init.definitions[0].name : null;
         var obj = expression(true);
         expect(")");
         return new AST_ForIn({
             init   : init,
-            name   : lhs,
             object : obj,
             body   : in_loop(statement)
         });
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index f252a7f4..9597b67f 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -4062,3 +4062,30 @@ cascade_statement: {
         }
     }
 }
+
+cascade_forin: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a;
+        function f(b) {
+            return [ b, b, b ];
+        }
+        for (var c in a = console, f(a))
+            console.log(c);
+    }
+    expect: {
+        var a;
+        function f(b) {
+            return [ b, b, b ];
+        }
+        for (var c in f(a = console))
+            console.log(c);
+    }
+    expect_stdout: [
+        "0",
+        "1",
+        "2",
+    ]
+}

From 7857354d85589aef285aac7c36c96fe4f7e2143e Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Tue, 16 Jan 2018 17:33:21 +0800
Subject: [PATCH 10/28] improve `test/travis-ufuzz.js` (#2795)

- print usage
- support concurrent jobs
- improve instance utilisation
- resume after V8 self-destruct
---
 test/travis-ufuzz.js | 42 ++++++++++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 14 deletions(-)

diff --git a/test/travis-ufuzz.js b/test/travis-ufuzz.js
index 579b7448..f84ed684 100644
--- a/test/travis-ufuzz.js
+++ b/test/travis-ufuzz.js
@@ -1,22 +1,29 @@
 "use strict";
 
+var child_process = require("child_process");
+var https = require("https");
+var url = require("url");
+
 var period = 45 * 60 * 1000;
 var wait = 2 * 60 * 1000;
 var ping = 5 * 60 * 1000;
-if (process.argv.length > 2) {
+if (process.argv[2] == "run") {
+    for (var i = 0; i < 2; i++) spawn();
+} else if (process.argv.length > 2) {
     var token = process.argv[2];
     var branch = process.argv[3] || "v" + require("../package.json").version;
-    var project = encodeURIComponent(process.argv[4] || "mishoo/UglifyJS2");
-    (function init() {
-        setTimeout(init, period + wait);
-        var options = require("url").parse("https://api.travis-ci.org/repo/" + project + "/requests");
+    var repository = encodeURIComponent(process.argv[4] || "mishoo/UglifyJS2");
+    var concurrency = process.argv[5] || 1;
+    (function request() {
+        setTimeout(request, (period + wait) / concurrency);
+        var options = url.parse("https://api.travis-ci.org/repo/" + repository + "/requests");
         options.method = "POST";
         options.headers = {
             "Content-Type": "application/json",
             "Travis-API-Version": 3,
             "Authorization": "token " + token
         };
-        require("https").request(options, function(res) {
+        https.request(options, function(res) {
             console.log("HTTP", res.statusCode);
             console.log(JSON.stringify(res.headers, null, 2));
             console.log();
@@ -31,22 +38,22 @@ if (process.argv.length > 2) {
                     language: "node_js",
                     node_js: "9",
                     sudo: false,
-                    script: "node test/travis-ufuzz"
+                    script: "node test/travis-ufuzz run"
                 }
             }
         }));
     })();
 } else {
-    var child = require("child_process").spawn("node", [
+    console.log("Usage: test/travis-ufuzz.js <token> [branch] [repository] [concurrency]");
+}
+
+function spawn() {
+    var child = child_process.spawn("node", [
         "--max-old-space-size=2048",
         "test/ufuzz"
     ], {
         stdio: [ "ignore", "pipe", "pipe" ]
-    }).on("exit", function() {
-        console.log(line);
-        clearInterval(keepAlive);
-        clearTimeout(timer);
-    });
+    }).on("exit", respawn);
     var line = "";
     child.stdout.on("data", function(data) {
         line += data;
@@ -61,7 +68,14 @@ if (process.argv.length > 2) {
     }, ping);
     var timer = setTimeout(function() {
         clearInterval(keepAlive);
-        child.removeAllListeners("exit");
+        child.removeListener("exit", respawn);
         child.kill();
     }, period);
+
+    function respawn() {
+        console.log(line);
+        clearInterval(keepAlive);
+        clearTimeout(timer);
+        spawn();
+    }
 }

From 224c14d49d0f007af641b8c7d358814634ea7c5f Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Tue, 16 Jan 2018 17:51:25 +0800
Subject: [PATCH 11/28] improve `mocha` tests (#2797)

- workaround sporadic delays from Travis CI
---
 test/mocha.js | 39 +++++++++++++++++----------------------
 1 file changed, 17 insertions(+), 22 deletions(-)

diff --git a/test/mocha.js b/test/mocha.js
index 411f52c5..fb8c3841 100644
--- a/test/mocha.js
+++ b/test/mocha.js
@@ -1,29 +1,24 @@
-var Mocha = require('mocha'),
-    fs = require('fs'),
-    path = require('path');
+var fs = require("fs");
+var Mocha = require("mocha");
+var path = require("path");
 
-// Instantiate a Mocha instance.
-var mocha = new Mocha({});
+// Instantiate a Mocha instance
+var mocha = new Mocha({
+    timeout: 5000
+});
+var testDir = __dirname + "/mocha/";
 
-var testDir = __dirname + '/mocha/';
-
-// Add each .js file to the mocha instance
-fs.readdirSync(testDir).filter(function(file){
-    // Only keep the .js files
-    return file.substr(-3) === '.js';
-
-}).forEach(function(file){
-    mocha.addFile(
-        path.join(testDir, file)
-    );
+// Add each .js file to the Mocha instance
+fs.readdirSync(testDir).filter(function(file) {
+    return /\.js$/.test(file);
+}).forEach(function(file) {
+    mocha.addFile(path.join(testDir, file));
 });
 
 module.exports = function() {
     mocha.run(function(failures) {
-        if (failures !== 0) {
-            process.on('exit', function () {
-                process.exit(failures);
-            });
-        }
+        if (failures) process.on("exit", function() {
+            process.exit(failures);
+        });
     });
-};
\ No newline at end of file
+};

From 79cfac77bdee04021db9f60111f55005919f7b67 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Wed, 17 Jan 2018 13:58:27 +0800
Subject: [PATCH 12/28] extend `join_vars` & `sequences` (#2798)

---
 lib/compress.js             | 88 +++++++++++++++++++++----------------
 test/compress/properties.js | 48 ++++++++++++++++++--
 test/compress/sequences.js  | 18 ++++++++
 3 files changed, 111 insertions(+), 43 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index cd5651a2..5fd49cf1 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1662,37 +1662,34 @@ merge(Compressor.prototype, {
             for (var i = 0; i < statements.length; i++) {
                 var stat = statements[i];
                 if (prev) {
-                    if (stat instanceof AST_For && !(stat.init instanceof AST_Definitions)) {
-                        var abort = false;
-                        prev.body.walk(new TreeWalker(function(node) {
-                            if (abort || node instanceof AST_Scope) return true;
-                            if (node instanceof AST_Binary && node.operator == "in") {
-                                abort = true;
-                                return true;
-                            }
-                        }));
-                        if (!abort) {
-                            if (stat.init) stat.init = cons_seq(stat.init);
-                            else {
-                                stat.init = prev.body;
-                                n--;
-                                CHANGED = true;
+                    if (stat instanceof AST_Exit) {
+                        stat.value = cons_seq(stat.value || make_node(AST_Undefined, stat).transform(compressor));
+                    } else if (stat instanceof AST_For) {
+                        if (!(stat.init instanceof AST_Definitions)) {
+                            var abort = false;
+                            prev.body.walk(new TreeWalker(function(node) {
+                                if (abort || node instanceof AST_Scope) return true;
+                                if (node instanceof AST_Binary && node.operator == "in") {
+                                    abort = true;
+                                    return true;
+                                }
+                            }));
+                            if (!abort) {
+                                if (stat.init) stat.init = cons_seq(stat.init);
+                                else {
+                                    stat.init = prev.body;
+                                    n--;
+                                    CHANGED = true;
+                                }
                             }
                         }
-                    }
-                    else if (stat instanceof AST_If) {
+                    } else if (stat instanceof AST_ForIn) {
+                        stat.object = cons_seq(stat.object);
+                    } else if (stat instanceof AST_If) {
                         stat.condition = cons_seq(stat.condition);
-                    }
-                    else if (stat instanceof AST_With) {
+                    } else if (stat instanceof AST_Switch) {
                         stat.expression = cons_seq(stat.expression);
-                    }
-                    else if (stat instanceof AST_Exit && stat.value) {
-                        stat.value = cons_seq(stat.value);
-                    }
-                    else if (stat instanceof AST_Exit) {
-                        stat.value = cons_seq(make_node(AST_Undefined, stat).transform(compressor));
-                    }
-                    else if (stat instanceof AST_Switch) {
+                    } else if (stat instanceof AST_With) {
                         stat.expression = cons_seq(stat.expression);
                     }
                 }
@@ -1775,18 +1772,7 @@ merge(Compressor.prototype, {
                         defs = stat;
                     }
                 } else if (stat instanceof AST_Exit) {
-                    var exprs = join_object_assignments(prev, stat.value);
-                    if (exprs) {
-                        CHANGED = true;
-                        if (exprs.length) {
-                            stat.value = make_sequence(stat.value, exprs);
-                        } else if (stat.value instanceof AST_Sequence) {
-                            stat.value = stat.value.tail_node().left;
-                        } else {
-                            stat.value = stat.value.left;
-                        }
-                    }
-                    statements[++j] = stat;
+                    stat.value = extract_object_assignments(stat.value);
                 } else if (stat instanceof AST_For) {
                     var exprs = join_object_assignments(prev, stat.init);
                     if (exprs) {
@@ -1808,6 +1794,10 @@ merge(Compressor.prototype, {
                     } else {
                         statements[++j] = stat;
                     }
+                } else if (stat instanceof AST_ForIn) {
+                    stat.object = extract_object_assignments(stat.object);
+                } else if (stat instanceof AST_If) {
+                    stat.condition = extract_object_assignments(stat.condition);
                 } else if (stat instanceof AST_SimpleStatement) {
                     var exprs = join_object_assignments(prev, stat.body);
                     if (exprs) {
@@ -1816,11 +1806,31 @@ merge(Compressor.prototype, {
                         stat.body = make_sequence(stat.body, exprs);
                     }
                     statements[++j] = stat;
+                } else if (stat instanceof AST_Switch) {
+                    stat.expression = extract_object_assignments(stat.expression);
+                } else if (stat instanceof AST_With) {
+                    stat.expression = extract_object_assignments(stat.expression);
                 } else {
                     statements[++j] = stat;
                 }
             }
             statements.length = j + 1;
+
+            function extract_object_assignments(value) {
+                statements[++j] = stat;
+                var exprs = join_object_assignments(prev, value);
+                if (exprs) {
+                    CHANGED = true;
+                    if (exprs.length) {
+                        return make_sequence(value, exprs);
+                    } else if (value instanceof AST_Sequence) {
+                        return value.tail_node().left;
+                    } else {
+                        return value.left;
+                    }
+                }
+                return value;
+            }
         }
     }
 
diff --git a/test/compress/properties.js b/test/compress/properties.js
index 7df53d39..933774d5 100644
--- a/test/compress/properties.js
+++ b/test/compress/properties.js
@@ -1189,7 +1189,7 @@ join_object_assignments_3: {
     expect_stdout: "PASS"
 }
 
-join_object_assignments_4: {
+join_object_assignments_return_1: {
     options = {
         join_vars: true,
     }
@@ -1213,7 +1213,7 @@ join_object_assignments_4: {
     expect_stdout: "foo"
 }
 
-join_object_assignments_5: {
+join_object_assignments_return_2: {
     options = {
         join_vars: true,
     }
@@ -1239,7 +1239,7 @@ join_object_assignments_5: {
     expect_stdout: "bar"
 }
 
-join_object_assignments_6: {
+join_object_assignments_return_3: {
     options = {
         join_vars: true,
     }
@@ -1271,7 +1271,7 @@ join_object_assignments_6: {
     ]
 }
 
-join_object_assignments_7: {
+join_object_assignments_for: {
     options = {
         join_vars: true,
     }
@@ -1298,3 +1298,43 @@ join_object_assignments_7: {
         "3",
     ]
 }
+
+join_object_assignments_if: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        console.log(function() {
+            var o = {};
+            if (o.a = "PASS") return o.a;
+        }())
+    }
+    expect: {
+        console.log(function() {
+            var o = { a: "PASS" };
+            if (o.a) return o.a;
+        }());
+    }
+    expect_stdout: "PASS"
+}
+
+join_object_assignments_forin: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        console.log(function() {
+            var o = {};
+            for (var a in o.a = "PASS", o)
+                return o[a];
+        }())
+    }
+    expect: {
+        console.log(function() {
+            var o = { a: "PASS" };
+            for (var a in o)
+                return o[a];
+        }());
+    }
+    expect_stdout: "PASS"
+}
diff --git a/test/compress/sequences.js b/test/compress/sequences.js
index 3d12fb0b..2c900796 100644
--- a/test/compress/sequences.js
+++ b/test/compress/sequences.js
@@ -859,3 +859,21 @@ for_init_var: {
     }
     expect_stdout: "PASS"
 }
+
+forin: {
+    options = {
+        sequences: true,
+    }
+    input: {
+        var o = [];
+        o.push("PASS");
+        for (var a in o)
+            console.log(o[a]);
+    }
+    expect: {
+        var o = [];
+        for (var a in o.push("PASS"), o)
+            console.log(o[a]);
+    }
+    expect_stdout: "PASS"
+}

From cff3bf49142e5d99ad07e182169a73f985b7b652 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Wed, 17 Jan 2018 15:12:22 +0800
Subject: [PATCH 13/28] configure `rename` with CLI (#2802)

---
 bin/uglifyjs               |  8 ++++++--
 test/input/rename/input.js |  6 ++++++
 test/mocha/cli.js          | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 test/input/rename/input.js

diff --git a/bin/uglifyjs b/bin/uglifyjs
index 9a3257e7..2ff1feb7 100755
--- a/bin/uglifyjs
+++ b/bin/uglifyjs
@@ -43,6 +43,7 @@ program.option("-d, --define <expr>[=value]", "Global definitions.", parse_js("d
 program.option("--ie8", "Support non-standard Internet Explorer 8.");
 program.option("--keep-fnames", "Do not mangle/drop function names. Useful for code relying on Function.prototype.name.");
 program.option("--name-cache <file>", "File to hold mangled name mappings.");
+program.option("--rename", "Force symbol expansion.");
 program.option("--no-rename", "Disable symbol expansion.");
 program.option("--self", "Build UglifyJS as a library (implies --wrap UglifyJS)");
 program.option("--source-map [options]", "Enable source map/specify source map options.", parse_source_map());
@@ -62,13 +63,11 @@ if (!program.output && program.sourceMap && program.sourceMap.url != "inline") {
     "compress",
     "ie8",
     "mangle",
-    "rename",
     "sourceMap",
     "toplevel",
     "wrap"
 ].forEach(function(name) {
     if (name in program) {
-        if (name == "rename" && program[name]) return;
         options[name] = program[name];
     }
 });
@@ -121,6 +120,11 @@ if (program.parse) {
         fatal("ERROR: inline source map only works with built-in parser");
     }
 }
+if (~program.rawArgs.indexOf("--rename")) {
+    options.rename = true;
+} else if (!program.rename) {
+    options.rename = false;
+}
 var convert_path = function(name) {
     return name;
 };
diff --git a/test/input/rename/input.js b/test/input/rename/input.js
new file mode 100644
index 00000000..ef6daed2
--- /dev/null
+++ b/test/input/rename/input.js
@@ -0,0 +1,6 @@
+function f(x) {
+    return g(x);
+    function g(x) {
+        return x;
+    }
+}
diff --git a/test/mocha/cli.js b/test/mocha/cli.js
index 85b2e8c9..671d700e 100644
--- a/test/mocha/cli.js
+++ b/test/mocha/cli.js
@@ -650,4 +650,36 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
+    it("Should work with explicit --rename", function(done) {
+        var command = uglifyjscmd + " test/input/rename/input.js --rename";
+        exec(command, function(err, stdout, stderr) {
+            if (err) throw err;
+            assert.strictEqual(stdout, "function f(a){return b(a);function b(c){return c}}\n");
+            done();
+        });
+    });
+    it("Should work with explicit --no-rename", function(done) {
+        var command = uglifyjscmd + " test/input/rename/input.js -mc --no-rename";
+        exec(command, function(err, stdout, stderr) {
+            if (err) throw err;
+            assert.strictEqual(stdout, "function f(n){return function(n){return n}(n)}\n");
+            done();
+        });
+    });
+    it("Should work with implicit --rename", function(done) {
+        var command = uglifyjscmd + " test/input/rename/input.js -mc";
+        exec(command, function(err, stdout, stderr) {
+            if (err) throw err;
+            assert.strictEqual(stdout, "function f(n){return n}\n");
+            done();
+        });
+    });
+    it("Should work with implicit --no-rename", function(done) {
+        var command = uglifyjscmd + " test/input/rename/input.js -c";
+        exec(command, function(err, stdout, stderr) {
+            if (err) throw err;
+            assert.strictEqual(stdout, "function f(x){return function(x){return x}(x)}\n");
+            done();
+        });
+    });
 });

From d3ce2bc9e73d9d98b34b261d282a18b9ce9d5880 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Wed, 17 Jan 2018 20:41:51 +0800
Subject: [PATCH 14/28] suppress `unsafe_proto` for LHS expressions (#2804)

---
 lib/compress.js             |  2 +-
 test/compress/properties.js | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/lib/compress.js b/lib/compress.js
index 5fd49cf1..64178227 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -5644,6 +5644,7 @@ merge(Compressor.prototype, {
         if (def) {
             return def.optimize(compressor);
         }
+        if (is_lhs(self, compressor.parent())) return self;
         if (compressor.option("unsafe_proto")
             && self.expression instanceof AST_Dot
             && self.expression.property == "prototype") {
@@ -5682,7 +5683,6 @@ merge(Compressor.prototype, {
                 break;
             }
         }
-        if (is_lhs(self, compressor.parent())) return self;
         var sub = self.flatten_object(self.property, compressor);
         if (sub) return sub.optimize(compressor);
         var ev = self.evaluate(compressor);
diff --git a/test/compress/properties.js b/test/compress/properties.js
index 933774d5..af115ff1 100644
--- a/test/compress/properties.js
+++ b/test/compress/properties.js
@@ -583,6 +583,25 @@ native_prototype: {
     }
 }
 
+native_prototype_lhs: {
+    options = {
+        unsafe_proto: true,
+    }
+    input: {
+        console.log(function() {
+            Function.prototype.bar = "PASS";
+            return function() {};
+        }().bar);
+    }
+    expect: {
+        console.log(function() {
+            Function.prototype.bar = "PASS";
+            return function() {};
+        }().bar);
+    }
+    expect_stdout: "PASS"
+}
+
 accessor_boolean: {
     input: {
         var a = 1;

From 07e4b64f3a8439a9491cc7a277872e0a5d79a29b Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Wed, 17 Jan 2018 21:33:13 +0800
Subject: [PATCH 15/28] fix `AST_Scope.clone()` (#2803)

fixes #2799
---
 lib/ast.js                   |  7 +++++
 lib/utils.js                 |  7 +++++
 test/compress/reduce_vars.js | 58 ++++++++++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+)

diff --git a/lib/ast.js b/lib/ast.js
index 4e41659c..19f6bfb5 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -308,6 +308,13 @@ var AST_Scope = DEFNODE("Scope", "variables functions uses_with uses_eval parent
         enclosed: "[SymbolDef*/S] a list of all symbol definitions that are accessed from this scope or any subscopes",
         cname: "[integer/S] current index for mangling variables (used internally by the mangler)",
     },
+    clone: function(deep) {
+        var node = this._clone(deep);
+        if (this.variables) node.variables = this.variables.clone();
+        if (this.functions) node.functions = this.functions.clone();
+        if (this.enclosed) node.enclosed = this.enclosed.slice();
+        return node;
+    }
 }, AST_Block);
 
 var AST_Toplevel = DEFNODE("Toplevel", "globals", {
diff --git a/lib/utils.js b/lib/utils.js
index dab7f566..9121fa93 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -303,6 +303,13 @@ Dictionary.prototype = {
             ret.push(f(this._values[i], i.substr(1)));
         return ret;
     },
+    clone: function() {
+        var ret = new Dictionary();
+        for (var i in this._values)
+            ret._values[i] = this._values[i];
+        ret._size = this._size;
+        return ret;
+    },
     toObject: function() { return this._values }
 };
 Dictionary.fromObject = function(obj) {
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index ec0471a8..33175d1b 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -5302,3 +5302,61 @@ issue_2774: {
     }
     expect_stdout: "undefined"
 }
+
+issue_2799_1: {
+    options = {
+        reduce_funcs: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            return f;
+            function f(n) {
+                function g(i) {
+                    return i && i + g(i - 1);
+                }
+                function h(j) {
+                    return g(j);
+                }
+                return h(n);
+            }
+        }()(5));
+    }
+    expect: {
+        console.log(function() {
+            return function(n) {
+                return function(j) {
+                    return function g(i) {
+                        return i && i + g(i - 1);
+                    }(j);
+                }(n);
+            }
+        }()(5));
+    }
+    expect_stdout: "15"
+}
+
+issue_2799_2: {
+    options = {
+        reduce_vars: true,
+        unsafe_proto: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            function foo() {
+                Function.prototype.call.apply(console.log, [ null, "PASS" ]);
+            }
+            foo();
+        })();
+    }
+    expect: {
+        (function() {
+            (function() {
+                (function() {}).call.apply(console.log, [ null, "PASS" ]);
+            })();
+        })();
+    }
+    expect_stdout: "PASS"
+}

From cc07f3b806f2a6ea971f290bd44425493f5c2e3d Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Thu, 18 Jan 2018 02:57:33 +0800
Subject: [PATCH 16/28] faster output of comments (#2806)

---
 lib/output.js | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/output.js b/lib/output.js
index 1b1ba2a4..805f0339 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -451,6 +451,11 @@ function OutputStream(options) {
         return OUTPUT;
     };
 
+    function has_nlb() {
+        var index = OUTPUT.lastIndexOf("\n");
+        return /^ *$/.test(OUTPUT.slice(index + 1));
+    }
+
     function prepend_comments(node) {
         var self = this;
         var start = node.start;
@@ -499,7 +504,7 @@ function OutputStream(options) {
 
         comments = comments.filter(comment_filter, node);
         if (comments.length == 0) return;
-        var last_nlb = /(^|\n) *$/.test(OUTPUT);
+        var last_nlb = has_nlb();
         comments.forEach(function(c, i) {
             if (!last_nlb) {
                 if (c.nlb) {
@@ -546,7 +551,7 @@ function OutputStream(options) {
                 print("\n");
                 indent();
                 need_newline_indented = false;
-            } else if (c.nlb && (i > 0 || !/(^|\n) *$/.test(OUTPUT))) {
+            } else if (c.nlb && (i > 0 || !has_nlb())) {
                 print("\n");
                 indent();
             } else if (i > 0 || !tail) {

From b335912e8690469044b89ccf93ac9dec11b273f7 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Thu, 18 Jan 2018 14:08:05 +0800
Subject: [PATCH 17/28] enhance `test/ufuzz.js` (#2808)

- standalone test for `rename`
- handle `keep_fargs` & `rename` upon failure
---
 test/ufuzz.js   | 24 ++++++++++++++++++++++--
 test/ufuzz.json |  3 ++-
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/test/ufuzz.js b/test/ufuzz.js
index d02e9f76..07b67a87 100644
--- a/test/ufuzz.js
+++ b/test/ufuzz.js
@@ -998,10 +998,11 @@ function log_suspects(minify_options, component) {
     if (typeof options != "object") options = {};
     var defs = default_options[component];
     var suspects = Object.keys(defs).filter(function(name) {
-        if ((name in options ? options : defs)[name]) {
+        var flip = name == "keep_fargs";
+        if (flip ? name in options : (name in options ? options : defs)[name]) {
             var m = JSON.parse(JSON.stringify(minify_options));
             var o = JSON.parse(JSON.stringify(options));
-            o[name] = false;
+            o[name] = flip;
             m[component] = o;
             var result = UglifyJS.minify(original_code, m);
             if (result.error) {
@@ -1022,6 +1023,24 @@ function log_suspects(minify_options, component) {
     }
 }
 
+function log_rename(options) {
+    if (!options.rename) return;
+    var m = JSON.parse(JSON.stringify(minify_options));
+    m.rename = false;
+    var result = UglifyJS.minify(original_code, m);
+    if (result.error) {
+        errorln("Error testing options.rename");
+        errorln(result.error.stack);
+    } else {
+        var r = sandbox.run_code(result.code);
+        if (sandbox.same_stdout(original_result, r)) {
+            errorln("Suspicious options:");
+            errorln("  rename");
+            errorln();
+        }
+    }
+}
+
 function log(options) {
     if (!ok) errorln('\n\n\n\n\n\n!!!!!!!!!!\n\n\n');
     errorln("//=============================================================");
@@ -1056,6 +1075,7 @@ function log(options) {
     errorln();
     if (!ok && typeof uglify_code == "string") {
         Object.keys(default_options).forEach(log_suspects.bind(null, options));
+        log_rename(options);
         errorln("!!!!!! Failed... round " + round);
     }
 }
diff --git a/test/ufuzz.json b/test/ufuzz.json
index 4057a351..f04b6417 100644
--- a/test/ufuzz.json
+++ b/test/ufuzz.json
@@ -5,7 +5,8 @@
         "output": {
             "beautify": true,
             "bracketize": true
-        }
+        },
+        "rename": true
     },
     {
         "compress": false

From 983e69128b0e6da78d71ad9b77d798f31a10ca44 Mon Sep 17 00:00:00 2001
From: kzc <kzc@users.noreply.github.com>
Date: Thu, 18 Jan 2018 08:52:54 -0500
Subject: [PATCH 18/28] fix `join_vars` property assignment for negative array
 index (#2810)

fixes #2790
---
 lib/compress.js             |   2 +-
 test/compress/properties.js | 204 ++++++++++++++++++++++++++++++++++++
 2 files changed, 205 insertions(+), 1 deletion(-)

diff --git a/lib/compress.js b/lib/compress.js
index 64178227..89056796 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1746,7 +1746,7 @@ merge(Compressor.prototype, {
                 }
                 if (prop instanceof AST_Node) break;
                 def.value.properties.push(make_node(AST_ObjectKeyVal, node, {
-                    key: prop,
+                    key: "" + prop,
                     value: node.right
                 }));
                 exprs.shift();
diff --git a/test/compress/properties.js b/test/compress/properties.js
index af115ff1..53684daa 100644
--- a/test/compress/properties.js
+++ b/test/compress/properties.js
@@ -1357,3 +1357,207 @@ join_object_assignments_forin: {
     }
     expect_stdout: "PASS"
 }
+
+join_object_assignments_negative: {
+    options = {
+        evaluate: true,
+        join_vars: true,
+        properties: true,
+    }
+    input: {
+        var o = {};
+        o[0] = 0;
+        o[-0] = 1;
+        o[-1] = 2;
+        console.log(o[0], o[-0], o[-1]);
+    }
+    expect: {
+        var o = {
+            0: 0,
+            0: 1,
+            "-1": 2
+        };
+        console.log(o[0], o[-0], o[-1]);
+    }
+    expect_stdout: "1 1 2"
+}
+
+join_object_assignments_NaN_1: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        var o = {};
+        o[NaN] = 1;
+        o[0/0] = 2;
+        console.log(o[NaN], o[NaN]);
+    }
+    expect: {
+        var o = {};
+        o[NaN] = 1;
+        o[0/0] = 2;
+        console.log(o[NaN], o[NaN]);
+    }
+    expect_stdout: "2 2"
+}
+
+join_object_assignments_NaN_2: {
+    options = {
+        evaluate: true,
+        join_vars: true,
+        properties: true,
+    }
+    input: {
+        var o = {};
+        o[NaN] = 1;
+        o[0/0] = 2;
+        console.log(o[NaN], o[NaN]);
+    }
+    expect: {
+        var o = {
+            NaN: 1,
+            NaN: 2
+        };
+        console.log(o.NaN, o.NaN);
+    }
+    expect_stdout: "2 2"
+}
+
+join_object_assignments_null_0: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        var o = {};
+        o[null] = 1;
+        console.log(o[null]);
+    }
+    expect: {
+        var o = {};
+        o[null] = 1;
+        console.log(o[null]);
+    }
+    expect_stdout: "1"
+}
+
+join_object_assignments_null_1: {
+    options = {
+        evaluate: true,
+        join_vars: true,
+        properties: true,
+    }
+    input: {
+        var o = {};
+        o[null] = 1;
+        console.log(o[null]);
+    }
+    expect: {
+        var o = {
+            null: 1
+        };
+        console.log(o.null);
+    }
+    expect_stdout: "1"
+}
+
+join_object_assignments_void_0: {
+    options = {
+        evaluate: true,
+        join_vars: true,
+    }
+    input: {
+        var o = {};
+        o[void 0] = 1;
+        console.log(o[void 0]);
+    }
+    expect: {
+        var o = {
+            undefined: 1
+        };
+        console.log(o[void 0]);
+    }
+    expect_stdout: "1"
+}
+
+join_object_assignments_undefined_1: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        var o = {};
+        o[undefined] = 1;
+        console.log(o[undefined]);
+    }
+    expect: {
+        var o = {};
+        o[void 0] = 1;
+        console.log(o[void 0]);
+    }
+    expect_stdout: "1"
+}
+
+join_object_assignments_undefined_2: {
+    options = {
+        evaluate: true,
+        join_vars: true,
+        properties: true,
+    }
+    input: {
+        var o = {};
+        o[undefined] = 1;
+        console.log(o[undefined]);
+    }
+    expect: {
+        var o = {
+            undefined : 1
+        };
+        console.log(o[void 0]);
+    }
+    expect_stdout: "1"
+}
+
+join_object_assignments_Infinity: {
+    options = {
+        evaluate: true,
+        join_vars: true,
+        properties: true,
+    }
+    input: {
+        var o = {};
+        o[Infinity] = 1;
+        o[1/0] = 2;
+        o[-Infinity] = 3;
+        o[-1/0] = 4;
+        console.log(o[Infinity], o[1/0], o[-Infinity], o[-1/0]);
+    }
+    expect: {
+        var o = {
+            Infinity: 1,
+            Infinity: 2,
+            "-Infinity": 3,
+            "-Infinity": 4
+        };
+        console.log(o[1/0], o[1/0], o[-1/0], o[-1/0]);
+    }
+    expect_stdout: "2 2 4 4"
+}
+
+join_object_assignments_regex: {
+    options = {
+        evaluate: true,
+        join_vars: true,
+        properties: true,
+    }
+    input: {
+        var o = {};
+        o[/rx/] = 1;
+        console.log(o[/rx/]);
+    }
+    expect: {
+        var o = {
+            "/rx/": 1
+        };
+        console.log(o[/rx/]);
+    }
+    expect_stdout: "1"
+}

From 082e004b872ecb158e5a28702898688742b5da86 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Fri, 19 Jan 2018 00:36:30 +0800
Subject: [PATCH 19/28] compress `undefined` property names (#2811)

- enforce property names as string
- handle `void 0` as `undefined` in `hoist_props` & `reduce_vars`
---
 lib/ast.js                   |  4 ++--
 lib/compress.js              | 21 ++++++++++++++++-----
 lib/output.js                |  7 ++-----
 lib/parse.js                 |  4 ++--
 test/compress/hoist_props.js | 22 ++++++++++++++++++++++
 test/compress/issue-1770.js  |  4 ++--
 6 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/lib/ast.js b/lib/ast.js
index 19f6bfb5..9b88b088 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -689,8 +689,8 @@ var AST_Object = DEFNODE("Object", "properties", {
 var AST_ObjectProperty = DEFNODE("ObjectProperty", "key value", {
     $documentation: "Base class for literal object properties",
     $propdoc: {
-        key: "[string] the property name converted to a string for ObjectKeyVal.  For setters and getters this is an AST_SymbolAccessor.",
-        value: "[AST_Node] property value.  For setters and getters this is an AST_Accessor."
+        key: "[string|AST_SymbolAccessor] property name. For ObjectKeyVal this is a string. For getters and setters this is an AST_SymbolAccessor.",
+        value: "[AST_Node] property value.  For getters and setters this is an AST_Accessor."
     },
     _walk: function(visitor) {
         return visitor._visit(this, function(){
diff --git a/lib/compress.js b/lib/compress.js
index 89056796..bda5d7a6 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -404,14 +404,15 @@ merge(Compressor.prototype, {
         }
 
         function read_property(obj, key) {
-            if (key instanceof AST_Constant) key = key.getValue();
-            if (key instanceof AST_Node) return null;
+            key = get_value(key);
+            if (key instanceof AST_Node) return;
             var value;
             if (obj instanceof AST_Array) {
                 var elements = obj.elements;
                 if (key == "length") return make_node_from_constant(elements.length, obj);
                 if (typeof key == "number" && key in elements) value = elements[key];
             } else if (obj instanceof AST_Object) {
+                key = "" + key;
                 var props = obj.properties;
                 for (var i = props.length; --i >= 0;) {
                     var prop = props[i];
@@ -1855,6 +1856,18 @@ merge(Compressor.prototype, {
         }));
     };
 
+    function get_value(key) {
+        if (key instanceof AST_Constant) {
+            return key.getValue();
+        }
+        if (key instanceof AST_UnaryPrefix
+            && key.operator == "void"
+            && key.expression instanceof AST_Constant) {
+            return;
+        }
+        return key;
+    }
+
     function is_undefined(node, compressor) {
         return node.is_undefined
             || node instanceof AST_Undefined
@@ -3295,9 +3308,7 @@ merge(Compressor.prototype, {
             if (node instanceof AST_PropAccess && node.expression instanceof AST_SymbolRef) {
                 var defs = defs_by_id[node.expression.definition().id];
                 if (defs) {
-                    var key = node.property;
-                    if (key instanceof AST_Node) key = key.getValue();
-                    var def = defs.get(key);
+                    var def = defs.get(get_value(node.property));
                     var sym = make_node(AST_SymbolRef, node, {
                         name: def.name,
                         scope: node.expression.scope,
diff --git a/lib/output.js b/lib/output.js
index 805f0339..bd1a70c2 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -1349,11 +1349,8 @@ function OutputStream(options) {
 
     function print_property_name(key, quote, output) {
         if (output.option("quote_keys")) {
-            output.print_string(key + "");
-        } else if ((typeof key == "number"
-                    || !output.option("beautify")
-                    && +key + "" == key)
-                   && parseFloat(key) >= 0) {
+            output.print_string(key);
+        } else if ("" + +key == key && key >= 0) {
             output.print(make_num(key));
         } else if (RESERVED_WORDS(key) ? !output.option("ie8") : is_identifier_string(key)) {
             if (quote && output.option("keep_quoted_props")) {
diff --git a/lib/parse.js b/lib/parse.js
index eba833dc..af631149 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -1365,7 +1365,7 @@ function parse($TEXT, options) {
             if (type == "name" && !is("punc", ":")) {
                 var key = new AST_SymbolAccessor({
                     start: S.token,
-                    name: as_property_name(),
+                    name: "" + as_property_name(),
                     end: prev()
                 });
                 if (name == "get") {
@@ -1391,7 +1391,7 @@ function parse($TEXT, options) {
             a.push(new AST_ObjectKeyVal({
                 start : start,
                 quote : start.quote,
-                key   : name,
+                key   : "" + name,
                 value : expression(false),
                 end   : prev()
             }));
diff --git a/test/compress/hoist_props.js b/test/compress/hoist_props.js
index 012a3fca..03867f78 100644
--- a/test/compress/hoist_props.js
+++ b/test/compress/hoist_props.js
@@ -664,3 +664,25 @@ issue_2519: {
     }
     expect_stdout: "5.5"
 }
+
+undefined_key: {
+    options = {
+        evaluate: true,
+        hoist_props: true,
+        join_vars: true,
+        passes: 4,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, o = {};
+        o[a] = 1;
+        o.b = 2;
+        console.log(o[a] + o.b);
+    }
+    expect: {
+        console.log(3);
+    }
+    expect_stdout: "3"
+}
diff --git a/test/compress/issue-1770.js b/test/compress/issue-1770.js
index f63f8453..7a529b2c 100644
--- a/test/compress/issue-1770.js
+++ b/test/compress/issue-1770.js
@@ -84,12 +84,12 @@ numeric_literal: {
         '    0: 0,',
         '    "-0": 1,',
         '    42: 2,',
-        '    "42": 3,',
+        '    42: 3,',
         '    37: 4,',
         '    o: 5,',
         '    1e42: 6,',
         '    b: 7,',
-        '    "1e+42": 8',
+        '    1e42: 8',
         '};',
         '',
         'console.log(obj[-0], obj[-""], obj["-0"]);',

From 81b64549ce1933974c904077eb3272ee0d4f4cf3 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Fri, 19 Jan 2018 06:11:19 +0800
Subject: [PATCH 20/28] fix time-out for respawned `test/ufuzz.js` (#2814)

---
 test/travis-ufuzz.js | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/test/travis-ufuzz.js b/test/travis-ufuzz.js
index f84ed684..36d1fc18 100644
--- a/test/travis-ufuzz.js
+++ b/test/travis-ufuzz.js
@@ -8,7 +8,8 @@ var period = 45 * 60 * 1000;
 var wait = 2 * 60 * 1000;
 var ping = 5 * 60 * 1000;
 if (process.argv[2] == "run") {
-    for (var i = 0; i < 2; i++) spawn();
+    var endTime = Date.now() + period;
+    for (var i = 0; i < 2; i++) spawn(endTime);
 } else if (process.argv.length > 2) {
     var token = process.argv[2];
     var branch = process.argv[3] || "v" + require("../package.json").version;
@@ -47,7 +48,7 @@ if (process.argv[2] == "run") {
     console.log("Usage: test/travis-ufuzz.js <token> [branch] [repository] [concurrency]");
 }
 
-function spawn() {
+function spawn(endTime) {
     var child = child_process.spawn("node", [
         "--max-old-space-size=2048",
         "test/ufuzz"
@@ -70,12 +71,12 @@ function spawn() {
         clearInterval(keepAlive);
         child.removeListener("exit", respawn);
         child.kill();
-    }, period);
+    }, endTime - Date.now());
 
     function respawn() {
         console.log(line);
         clearInterval(keepAlive);
         clearTimeout(timer);
-        spawn();
+        spawn(endTime);
     }
 }

From ac9a168fba726d9ab437478c81626f098997d116 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Fri, 19 Jan 2018 14:07:20 +0800
Subject: [PATCH 21/28] fix & improve `test/ufuzz.js` (#2815)

- use correct `options` when testing `rename`
- mask arbitrarily assigned function IDs to reduce rate of false positives
---
 test/sandbox.js | 24 +++++++++++++++---------
 test/ufuzz.js   |  2 +-
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/test/sandbox.js b/test/sandbox.js
index 2ce9f6e1..c660353c 100644
--- a/test/sandbox.js
+++ b/test/sandbox.js
@@ -17,24 +17,30 @@ function safe_log(arg, level) {
     return arg;
 }
 
+function strip_func_ids(text) {
+    return text.toString().replace(/F[0-9]{6}N/g, "<F<>N>");
+}
+
 var FUNC_TOSTRING = [
+    "[ Array, Boolean, Error, Function, Number, Object, RegExp, String].forEach(function(f) {",
+    "    f.toString = Function.prototype.toString;",
+    "    f.valueOf = Function.prototype.valueOf;",
+    "});",
     "Function.prototype.toString = Function.prototype.valueOf = function() {",
     "    var id = 100000;",
     "    return function() {",
-    '        if (this === Array) return "[Function: Array]";',
-    '        if (this === Object) return "[Function: Object]";',
-    "        var i = this.name;",
-    '        if (typeof i != "number") {',
-    "            i = ++id;",
+    "        var n = this.name;",
+    '        if (!/^F[0-9]{6}N$/.test(n)) {',
+    '            n = "F" + ++id + "N";',
 ].concat(Object.getOwnPropertyDescriptor(Function.prototype, "name").configurable ? [
     '            Object.defineProperty(this, "name", {',
     "                get: function() {",
-    "                    return i;",
+    "                    return n;",
     "                }",
     "            });",
 ] : [], [
     "        }",
-    '        return "[Function: " + i + "]";',
+    '        return "[Function: " + n + "]";',
     "    }",
     "}();",
     'Object.defineProperty(Function.prototype, "valueOf", { enumerable: false });',
@@ -77,7 +83,7 @@ exports.same_stdout = semver.satisfies(process.version, "0.12") ? function(expec
         expected = expected.message.slice(expected.message.lastIndexOf("\n") + 1);
         actual = actual.message.slice(actual.message.lastIndexOf("\n") + 1);
     }
-    return expected == actual;
+    return strip_func_ids(expected) == strip_func_ids(actual);
 } : function(expected, actual) {
-    return typeof expected == typeof actual && expected.toString() == actual.toString();
+    return typeof expected == typeof actual && strip_func_ids(expected) == strip_func_ids(actual);
 };
diff --git a/test/ufuzz.js b/test/ufuzz.js
index 07b67a87..bbf4fa09 100644
--- a/test/ufuzz.js
+++ b/test/ufuzz.js
@@ -1025,7 +1025,7 @@ function log_suspects(minify_options, component) {
 
 function log_rename(options) {
     if (!options.rename) return;
-    var m = JSON.parse(JSON.stringify(minify_options));
+    var m = JSON.parse(JSON.stringify(options));
     m.rename = false;
     var result = UglifyJS.minify(original_code, m);
     if (result.error) {

From e21bab7ce65e6a4db0ea966b3336eaab2a634e6e Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Fri, 19 Jan 2018 20:13:50 +0800
Subject: [PATCH 22/28] avoid duplicate property names in object literals under
 "use strict" (#2818)

fixes #2816
---
 lib/compress.js             | 12 +++++++++---
 test/compress/properties.js | 27 +++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index bda5d7a6..00593e81 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -893,7 +893,7 @@ merge(Compressor.prototype, {
                 sequencesize_2(statements, compressor);
             }
             if (compressor.option("join_vars")) {
-                join_consecutive_vars(statements, compressor);
+                join_consecutive_vars(statements);
             }
             if (compressor.option("collapse_vars")) {
                 collapse(statements, compressor);
@@ -1746,8 +1746,14 @@ merge(Compressor.prototype, {
                     prop = prop.evaluate(compressor);
                 }
                 if (prop instanceof AST_Node) break;
+                prop = "" + prop;
+                if (compressor.has_directive("use strict")) {
+                    if (!all(def.value.properties, function(node) {
+                        return node.key != prop && node.key.name != prop;
+                    })) break;
+                }
                 def.value.properties.push(make_node(AST_ObjectKeyVal, node, {
-                    key: "" + prop,
+                    key: prop,
                     value: node.right
                 }));
                 exprs.shift();
@@ -1756,7 +1762,7 @@ merge(Compressor.prototype, {
             return trimmed && exprs;
         }
 
-        function join_consecutive_vars(statements, compressor) {
+        function join_consecutive_vars(statements) {
             var defs;
             for (var i = 0, j = -1, len = statements.length; i < len; i++) {
                 var stat = statements[i];
diff --git a/test/compress/properties.js b/test/compress/properties.js
index 53684daa..dbc7bf2d 100644
--- a/test/compress/properties.js
+++ b/test/compress/properties.js
@@ -1561,3 +1561,30 @@ join_object_assignments_regex: {
     }
     expect_stdout: "1"
 }
+
+issue_2816: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        "use strict";
+        var o = {
+            a: 1
+        };
+        o.b = 2;
+        o.a = 3;
+        o.c = 4;
+        console.log(o.a, o.b, o.c);
+    }
+    expect: {
+        "use strict";
+        var o = {
+            a: 1,
+            b: 2
+        };
+        o.a = 3;
+        o.c = 4;
+        console.log(o.a, o.b, o.c);
+    }
+    expect_stdout: "3 2 4"
+}

From 3e7873217cad8b6f67839cb06d1e126ca231bc42 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Fri, 19 Jan 2018 20:41:57 +0800
Subject: [PATCH 23/28] improve `unused` on built-in functions (#2817)

---
 lib/compress.js                | 216 +++++++++++++++++++++------------
 test/compress/collapse_vars.js |  23 ++++
 test/compress/dead-code.js     |  17 +++
 test/compress/evaluate.js      |  36 ++++--
 4 files changed, 205 insertions(+), 87 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index 00593e81..5235a05f 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2113,6 +2113,95 @@ merge(Compressor.prototype, {
         return (first_in_statement(compressor) ? best_of_statement : best_of_expression)(ast1, ast2);
     }
 
+    function convert_to_predicate(obj) {
+        for (var key in obj) {
+            obj[key] = makePredicate(obj[key]);
+        }
+    }
+
+    var object_fns = [
+        "constructor",
+        "toString",
+        "valueOf",
+    ];
+    var native_fns = {
+        Array: [
+            "indexOf",
+            "join",
+            "lastIndexOf",
+            "slice",
+        ].concat(object_fns),
+        Boolean: object_fns,
+        Number: [
+            "toExponential",
+            "toFixed",
+            "toPrecision",
+        ].concat(object_fns),
+        Object: object_fns,
+        RegExp: [
+            "test",
+        ].concat(object_fns),
+        String: [
+            "charAt",
+            "charCodeAt",
+            "concat",
+            "indexOf",
+            "italics",
+            "lastIndexOf",
+            "match",
+            "replace",
+            "search",
+            "slice",
+            "split",
+            "substr",
+            "substring",
+            "trim",
+        ].concat(object_fns),
+    };
+    convert_to_predicate(native_fns);
+    var static_fns = {
+        Array: [
+            "isArray",
+        ],
+        Math: [
+            "abs",
+            "acos",
+            "asin",
+            "atan",
+            "ceil",
+            "cos",
+            "exp",
+            "floor",
+            "log",
+            "round",
+            "sin",
+            "sqrt",
+            "tan",
+            "atan2",
+            "pow",
+            "max",
+            "min",
+        ],
+        Number: [
+            "isFinite",
+            "isNaN",
+        ],
+        Object: [
+            "create",
+            "getOwnPropertyDescriptor",
+            "getOwnPropertyNames",
+            "getPrototypeOf",
+            "isExtensible",
+            "isFrozen",
+            "isSealed",
+            "keys",
+        ],
+        String: [
+            "fromCharCode",
+        ],
+    };
+    convert_to_predicate(static_fns);
+
     // methods to evaluate a constant expression
     (function(def){
         // If the node has been successfully reduced to a constant,
@@ -2278,13 +2367,9 @@ merge(Compressor.prototype, {
             Array: Array,
             Math: Math,
             Number: Number,
+            Object: Object,
             String: String,
         };
-        function convert_to_predicate(obj) {
-            for (var key in obj) {
-                obj[key] = makePredicate(obj[key]);
-            }
-        }
         var static_values = {
             Math: [
                 "E",
@@ -2325,77 +2410,6 @@ merge(Compressor.prototype, {
             }
             return this;
         });
-        var object_fns = [
-            "constructor",
-            "toString",
-            "valueOf",
-        ];
-        var native_fns = {
-            Array: [
-                "indexOf",
-                "join",
-                "lastIndexOf",
-                "slice",
-            ].concat(object_fns),
-            Boolean: object_fns,
-            Number: [
-                "toExponential",
-                "toFixed",
-                "toPrecision",
-            ].concat(object_fns),
-            RegExp: [
-                "test",
-            ].concat(object_fns),
-            String: [
-                "charAt",
-                "charCodeAt",
-                "concat",
-                "indexOf",
-                "italics",
-                "lastIndexOf",
-                "match",
-                "replace",
-                "search",
-                "slice",
-                "split",
-                "substr",
-                "substring",
-                "trim",
-            ].concat(object_fns),
-        };
-        convert_to_predicate(native_fns);
-        var static_fns = {
-            Array: [
-                "isArray",
-            ],
-            Math: [
-                "abs",
-                "acos",
-                "asin",
-                "atan",
-                "ceil",
-                "cos",
-                "exp",
-                "floor",
-                "log",
-                "round",
-                "sin",
-                "sqrt",
-                "tan",
-                "atan2",
-                "pow",
-                "max",
-                "min"
-            ],
-            Number: [
-                "isFinite",
-                "isNaN",
-            ],
-            String: [
-                "fromCharCode",
-            ],
-        };
-        convert_to_predicate(static_fns);
         def(AST_Call, function(compressor, depth) {
             var exp = this.expression;
             if (compressor.option("unsafe") && exp instanceof AST_PropAccess) {
@@ -2420,7 +2434,16 @@ merge(Compressor.prototype, {
                     if (arg === value) return this;
                     args.push(value);
                 }
-                return val[key].apply(val, args);
+                try {
+                    return val[key].apply(val, args);
+                } catch (ex) {
+                    compressor.warn("Error evaluating {code} [{file}:{line},{col}]", {
+                        code: this.print_to_string(),
+                        file: this.start.file,
+                        line: this.start.line,
+                        col: this.start.col
+                    });
+                }
             }
             return this;
         });
@@ -2511,9 +2534,34 @@ merge(Compressor.prototype, {
         if (compressor.option("unsafe")) {
             var expr = this.expression;
             if (is_undeclared_ref(expr) && global_pure_fns(expr.name)) return true;
+            if (expr instanceof AST_Dot
+                && is_undeclared_ref(expr.expression)
+                && (static_fns[expr.expression.name] || return_false)(expr.property)) {
+                return true;
+            }
         }
         return this.pure || !compressor.pure_funcs(this);
     });
+    AST_Node.DEFMETHOD("is_call_pure", return_false);
+    AST_Dot.DEFMETHOD("is_call_pure", function(compressor) {
+        if (!compressor.option("unsafe")) return;
+        var expr = this.expression;
+        var fns = return_false;
+        if (expr instanceof AST_Array) {
+            fns = native_fns.Array;
+        } else if (expr.is_boolean()) {
+            fns = native_fns.Boolean;
+        } else if (expr.is_number(compressor)) {
+            fns = native_fns.Number;
+        } else if (expr instanceof AST_RegExp) {
+            fns = native_fns.RegExp;
+        } else if (expr.is_string(compressor)) {
+            fns = native_fns.String;
+        } else if (!this.may_throw_on_access(compressor)) {
+            fns = native_fns.Object;
+        }
+        return fns(this.property);
+    });
 
     // determine if expression has side effects
     (function(def){
@@ -2534,8 +2582,12 @@ merge(Compressor.prototype, {
             return any(this.body, compressor);
         });
         def(AST_Call, function(compressor){
-            return !this.is_expr_pure(compressor)
-                || any(this.args, compressor);
+            if (!this.is_expr_pure(compressor)
+                && (!this.expression.is_call_pure(compressor)
+                    || this.expression.has_side_effects(compressor))) {
+                return true;
+            }
+            return any(this.args, compressor);
         });
         def(AST_Switch, function(compressor){
             return this.expression.has_side_effects(compressor)
@@ -3365,6 +3417,12 @@ merge(Compressor.prototype, {
         def(AST_This, return_null);
         def(AST_Call, function(compressor, first_in_statement){
             if (!this.is_expr_pure(compressor)) {
+                if (this.expression.is_call_pure(compressor)) {
+                    var exprs = this.args.slice();
+                    exprs.unshift(this.expression.expression);
+                    exprs = trim(exprs, compressor, first_in_statement);
+                    return exprs && make_sequence(this, exprs);
+                }
                 if (this.expression instanceof AST_Function
                     && (!this.expression.name || !this.expression.name.definition().references.length)) {
                     var node = this.clone();
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index 9597b67f..970f822e 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -4089,3 +4089,26 @@ cascade_forin: {
         "2",
     ]
 }
+
+unsafe_builtin: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            var b = Math.abs(a);
+            return Math.pow(b, 2);
+        }
+        console.log(f(-1), f(2));
+    }
+    expect: {
+        function f(a) {
+            return Math.pow(Math.abs(a), 2);
+        }
+        console.log(f(-1), f(2));
+    }
+    expect_stdout: "1 4"
+}
diff --git a/test/compress/dead-code.js b/test/compress/dead-code.js
index afc8c568..b66d5ac1 100644
--- a/test/compress/dead-code.js
+++ b/test/compress/dead-code.js
@@ -862,3 +862,20 @@ issue_2749: {
     }
     expect_stdout: "PASS"
 }
+
+unsafe_builtin: {
+    options = {
+        side_effects: true,
+        unsafe: true,
+    }
+    input: {
+        (!w).constructor(x);
+        Math.abs(y);
+        [ 1, 2, z ].valueOf();
+    }
+    expect: {
+        w, x;
+        y;
+        z;
+    }
+}
diff --git a/test/compress/evaluate.js b/test/compress/evaluate.js
index 6106fce3..d40880f3 100644
--- a/test/compress/evaluate.js
+++ b/test/compress/evaluate.js
@@ -1194,6 +1194,9 @@ issue_2231_1: {
         console.log(Object.keys(void 0));
     }
     expect_stdout: true
+    expect_warnings: [
+        "WARN: Error evaluating Object.keys(void 0) [test/compress/evaluate.js:1191,20]",
+    ]
 }
 
 issue_2231_2: {
@@ -1208,6 +1211,23 @@ issue_2231_2: {
         console.log(Object.getOwnPropertyNames(null));
     }
     expect_stdout: true
+    expect_warnings: [
+        "WARN: Error evaluating Object.getOwnPropertyNames(null) [test/compress/evaluate.js:1208,20]",
+    ]
+}
+
+issue_2231_3: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(Object.keys({ foo: "bar" })[0]);
+    }
+    expect: {
+        console.log("foo");
+    }
+    expect_stdout: "foo"
 }
 
 self_comparison_1: {
@@ -1330,13 +1350,13 @@ issue_2535_3: {
     }
     expect_stdout: true
     expect_warnings: [
-        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1316,20]",
-        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1317,20]",
-        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1318,20]",
-        "WARN: Condition left of && always false [test/compress/evaluate.js:1318,20]",
-        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1319,20]",
-        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1320,20]",
-        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1321,20]",
-        "WARN: Condition left of || always true [test/compress/evaluate.js:1321,20]",
+        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1336,20]",
+        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1337,20]",
+        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1338,20]",
+        "WARN: Condition left of && always false [test/compress/evaluate.js:1338,20]",
+        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1339,20]",
+        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1340,20]",
+        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1341,20]",
+        "WARN: Condition left of || always true [test/compress/evaluate.js:1341,20]",
     ]
 }

From 069df27bf18247a3e2f1d1a4abd0ee4fe28ef0ce Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Fri, 19 Jan 2018 23:47:42 +0800
Subject: [PATCH 24/28] enable `unsafe` for `test/ufuzz.js` (#2819)

- introduce `unsafe_undefined`
- safer `.toString()` compression

Miscellaneous
- rename `unsafe_Function`
---
 README.md                   |  9 +++++----
 lib/compress.js             | 19 +++++++++++--------
 test/compress/functions.js  |  2 +-
 test/compress/issue-1443.js |  4 ++--
 test/compress/issue-1588.js |  2 +-
 test/compress/sequences.js  |  2 +-
 test/ufuzz.json             |  8 +++++++-
 7 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/README.md b/README.md
index df90d1ca..99e33af7 100644
--- a/README.md
+++ b/README.md
@@ -737,7 +737,7 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
   comparison are switching. Compression only works if both `comparisons` and
   `unsafe_comps` are both set to true.
 
-- `unsafe_Func` (default: `false`) -- compress and mangle `Function(args, code)`
+- `unsafe_Function` (default: `false`) -- compress and mangle `Function(args, code)`
   when both `args` and `code` are string literals.
 
 - `unsafe_math` (default: `false`) -- optimize numerical expressions like
@@ -749,6 +749,10 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 - `unsafe_regexp` (default: `false`) -- enable substitutions of variables with
   `RegExp` values the same way as if they are constants.
 
+- `unsafe_undefined` (default: `false`) -- substitute `void 0` if there is a
+  variable named `undefined` in scope (variable name will be mangled, typically
+  reduced to a single character)
+
 - `unused` (default: `true`) -- drop unreferenced functions and variables (simple
   direct variable assignments do not count as references unless set to `"keep_assign"`)
 
@@ -922,9 +926,6 @@ when this flag is on:
 - `new Object()` → `{}`
 - `String(exp)` or `exp.toString()` → `"" + exp`
 - `new Object/RegExp/Function/Error/Array (...)` → we discard the `new`
-- `void 0` → `undefined` (if there is a variable named "undefined" in
-  scope; we do it because the variable name will be mangled, typically
-  reduced to a single character)
 
 ### Conditional compilation
 
diff --git a/lib/compress.js b/lib/compress.js
index 5235a05f..49185aec 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -84,10 +84,11 @@ function Compressor(options, false_by_default) {
         typeofs       : !false_by_default,
         unsafe        : false,
         unsafe_comps  : false,
-        unsafe_Func   : false,
+        unsafe_Function: false,
         unsafe_math   : false,
         unsafe_proto  : false,
         unsafe_regexp : false,
+        unsafe_undefined: false,
         unused        : !false_by_default,
         warnings      : false,
     }, true);
@@ -4100,11 +4101,13 @@ merge(Compressor.prototype, {
                 break;
             } else if (exp instanceof AST_Dot) switch(exp.property) {
               case "toString":
-                if (self.args.length == 0) return make_node(AST_Binary, self, {
-                    left: make_node(AST_String, self, { value: "" }),
-                    operator: "+",
-                    right: exp.expression
-                }).optimize(compressor);
+                if (self.args.length == 0 && !exp.expression.may_throw_on_access(compressor)) {
+                    return make_node(AST_Binary, self, {
+                        left: make_node(AST_String, self, { value: "" }),
+                        operator: "+",
+                        right: exp.expression
+                    }).optimize(compressor);
+                }
                 break;
               case "join":
                 if (exp.expression instanceof AST_Array) EXIT: {
@@ -4212,7 +4215,7 @@ merge(Compressor.prototype, {
                 break;
             }
         }
-        if (compressor.option("unsafe_Func")
+        if (compressor.option("unsafe_Function")
             && is_undeclared_ref(exp)
             && exp.name == "Function") {
             // new Function() => function(){}
@@ -5220,7 +5223,7 @@ merge(Compressor.prototype, {
     }
 
     OPT(AST_Undefined, function(self, compressor){
-        if (compressor.option("unsafe")) {
+        if (compressor.option("unsafe_undefined")) {
             var undef = find_variable(compressor, "undefined");
             if (undef) {
                 var ref = make_node(AST_SymbolRef, self, {
diff --git a/test/compress/functions.js b/test/compress/functions.js
index 2d55dd52..87328820 100644
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -218,7 +218,7 @@ issue_203: {
     options = {
         keep_fargs: false,
         side_effects: true,
-        unsafe_Func: true,
+        unsafe_Function: true,
         unused: true,
     }
     input: {
diff --git a/test/compress/issue-1443.js b/test/compress/issue-1443.js
index 304a71ac..18554ff6 100644
--- a/test/compress/issue-1443.js
+++ b/test/compress/issue-1443.js
@@ -4,7 +4,7 @@ unsafe_undefined: {
     options = {
         conditionals: true,
         if_return: true,
-        unsafe: true
+        unsafe_undefined: true,
     }
     mangle = {}
     input: {
@@ -30,7 +30,7 @@ keep_fnames: {
     options = {
         conditionals: true,
         if_return: true,
-        unsafe: true
+        unsafe_undefined: true,
     }
     mangle = {
         keep_fnames: true
diff --git a/test/compress/issue-1588.js b/test/compress/issue-1588.js
index 187d9f6c..40efb63b 100644
--- a/test/compress/issue-1588.js
+++ b/test/compress/issue-1588.js
@@ -61,7 +61,7 @@ unsafe_undefined: {
     options = {
         conditionals: true,
         if_return: true,
-        unsafe: true,
+        unsafe_undefined: true,
     }
     mangle = {}
     input: {
diff --git a/test/compress/sequences.js b/test/compress/sequences.js
index 2c900796..03075bf1 100644
--- a/test/compress/sequences.js
+++ b/test/compress/sequences.js
@@ -288,7 +288,7 @@ unsafe_undefined: {
         if_return: true,
         sequences: true,
         side_effects: true,
-        unsafe: true,
+        unsafe_undefined: true,
     }
     input: {
         function f(undefined) {
diff --git a/test/ufuzz.json b/test/ufuzz.json
index f04b6417..5ccd96e0 100644
--- a/test/ufuzz.json
+++ b/test/ufuzz.json
@@ -21,7 +21,13 @@
     {
         "compress": {
             "keep_fargs": false,
-            "passes": 100
+            "passes": 1e6,
+            "sequences": 1e6,
+            "unsafe": true,
+            "unsafe_Function": true,
+            "unsafe_math": true,
+            "unsafe_proto": true,
+            "unsafe_regexp": true
         }
     }
 ]

From e2dc9cf091684638a75035e7acddbc32ac5c0785 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Sun, 21 Jan 2018 01:39:44 +0800
Subject: [PATCH 25/28] fix `unsafe` `evaluate` of `AST_Array` (#2825)

fixes #2822
---
 lib/compress.js           |  5 ++++-
 test/compress/evaluate.js | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/lib/compress.js b/lib/compress.js
index 49185aec..2803b85c 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2240,7 +2240,10 @@ merge(Compressor.prototype, {
                 var elements = [];
                 for (var i = 0, len = this.elements.length; i < len; i++) {
                     var element = this.elements[i];
-                    if (element instanceof AST_Function) continue;
+                    if (element instanceof AST_Function) {
+                        elements.push(element);
+                        continue;
+                    }
                     var value = element._eval(compressor, depth);
                     if (element === value) return this;
                     elements.push(value);
diff --git a/test/compress/evaluate.js b/test/compress/evaluate.js
index d40880f3..0d26982c 100644
--- a/test/compress/evaluate.js
+++ b/test/compress/evaluate.js
@@ -1360,3 +1360,17 @@ issue_2535_3: {
         "WARN: Condition left of || always true [test/compress/evaluate.js:1341,20]",
     ]
 }
+
+issue_2822: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        console.log([ function() {}, "PASS", "FAIL" ][1]);
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}

From 06166df999f71a033d52e1a6213c36dd5bace2e8 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Sun, 21 Jan 2018 07:08:01 +0000
Subject: [PATCH 26/28] v3.3.8

---
 package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package.json b/package.json
index aaf6370b..a8ea8408 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,7 @@
   "homepage": "http://lisperator.net/uglifyjs",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.3.7",
+  "version": "3.3.8",
   "engines": {
     "node": ">=0.8.0"
   },

From 13accdd745caf857ad8877caf2a93594ddaeb769 Mon Sep 17 00:00:00 2001
From: alexlamsl <alexlamsl@gmail.com>
Date: Sun, 21 Jan 2018 15:53:32 +0800
Subject: [PATCH 27/28] fix tests

---
 test/compress/evaluate.js  | 20 ++++++++++----------
 test/compress/harmony.js   |  6 ++----
 test/compress/issue-203.js |  6 +++---
 test/mocha/cli.js          | 32 --------------------------------
 4 files changed, 15 insertions(+), 49 deletions(-)

diff --git a/test/compress/evaluate.js b/test/compress/evaluate.js
index 0230de10..7792dc94 100644
--- a/test/compress/evaluate.js
+++ b/test/compress/evaluate.js
@@ -1288,7 +1288,7 @@ issue_2231_1: {
     }
     expect_stdout: true
     expect_warnings: [
-        "WARN: Error evaluating Object.keys(void 0) [test/compress/evaluate.js:1191,20]",
+        "WARN: Error evaluating Object.keys(void 0) [test/compress/evaluate.js:1284,20]",
     ]
 }
 
@@ -1305,7 +1305,7 @@ issue_2231_2: {
     }
     expect_stdout: true
     expect_warnings: [
-        "WARN: Error evaluating Object.getOwnPropertyNames(null) [test/compress/evaluate.js:1208,20]",
+        "WARN: Error evaluating Object.getOwnPropertyNames(null) [test/compress/evaluate.js:1301,20]",
     ]
 }
 
@@ -1443,14 +1443,14 @@ issue_2535_3: {
     }
     expect_stdout: true
     expect_warnings: [
-        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1409,20]",
-        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1410,20]",
-        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1411,20]",
-        "WARN: Condition left of && always false [test/compress/evaluate.js:1411,20]",
-        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1412,20]",
-        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1413,20]",
-        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1414,20]",
-        "WARN: Condition left of || always true [test/compress/evaluate.js:1414,20]",
+        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1429,20]",
+        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1430,20]",
+        "WARN: Dropping side-effect-free && [test/compress/evaluate.js:1431,20]",
+        "WARN: Condition left of && always false [test/compress/evaluate.js:1431,20]",
+        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1432,20]",
+        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1433,20]",
+        "WARN: Dropping side-effect-free || [test/compress/evaluate.js:1434,20]",
+        "WARN: Condition left of || always true [test/compress/evaluate.js:1434,20]",
     ]
 }
 
diff --git a/test/compress/harmony.js b/test/compress/harmony.js
index f8120eae..29a27b7d 100644
--- a/test/compress/harmony.js
+++ b/test/compress/harmony.js
@@ -1276,8 +1276,7 @@ issue_2794_1: {
     }
     expect: {
         function foo() {
-            for (const a of (va = value, doSomething(va))) console.log(a);
-            var va;
+            for (const a of doSomething(value)) console.log(a);
         }
         function doSomething(x) {
             return [ x, 2 * x, 3 * x ];
@@ -1326,8 +1325,7 @@ issue_2794_2: {
     }
     expect: {
         function foo() {
-            for (const n of (o = value, doSomething(o))) console.log(n);
-            var o;
+            for (const o of doSomething(value)) console.log(o);
         }
         function doSomething(o) {
             return [ o, 2 * o, 3 * o ];
diff --git a/test/compress/issue-203.js b/test/compress/issue-203.js
index 896982b5..e95ca23e 100644
--- a/test/compress/issue-203.js
+++ b/test/compress/issue-203.js
@@ -2,7 +2,7 @@
 compress_new_function: {
     options = {
         unsafe: true,
-        unsafe_Func: true,
+        unsafe_Function: true,
     }
     input: {
         new Function("aa, bb", 'return aa;');
@@ -15,7 +15,7 @@ compress_new_function: {
 compress_new_function_with_destruct: {
     options = {
         unsafe: true,
-        unsafe_Func: true,
+        unsafe_Function: true,
         ecma: 6
     }
     beautify = {
@@ -38,7 +38,7 @@ compress_new_function_with_destruct_arrows: {
         arrows: true,
         unsafe_arrows: true,
         unsafe: true,
-        unsafe_Func: true,
+        unsafe_Function: true,
         ecma: 6,
     }
     beautify = {
diff --git a/test/mocha/cli.js b/test/mocha/cli.js
index 33e111a2..3804d823 100644
--- a/test/mocha/cli.js
+++ b/test/mocha/cli.js
@@ -743,36 +743,4 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
-    it("Should work with explicit --rename", function(done) {
-        var command = uglifyjscmd + " test/input/rename/input.js --rename";
-        exec(command, function(err, stdout, stderr) {
-            if (err) throw err;
-            assert.strictEqual(stdout, "function f(a){return b(a);function b(c){return c}}\n");
-            done();
-        });
-    });
-    it("Should work with explicit --no-rename", function(done) {
-        var command = uglifyjscmd + " test/input/rename/input.js -mc --no-rename";
-        exec(command, function(err, stdout, stderr) {
-            if (err) throw err;
-            assert.strictEqual(stdout, "function f(n){return function(n){return n}(n)}\n");
-            done();
-        });
-    });
-    it("Should work with implicit --rename", function(done) {
-        var command = uglifyjscmd + " test/input/rename/input.js -mc";
-        exec(command, function(err, stdout, stderr) {
-            if (err) throw err;
-            assert.strictEqual(stdout, "function f(n){return n}\n");
-            done();
-        });
-    });
-    it("Should work with implicit --no-rename", function(done) {
-        var command = uglifyjscmd + " test/input/rename/input.js -c";
-        exec(command, function(err, stdout, stderr) {
-            if (err) throw err;
-            assert.strictEqual(stdout, "function f(x){return function(x){return x}(x)}\n");
-            done();
-        });
-    });
 });

From fc98d212db69dde8ce15e2511984924ebf4b1e55 Mon Sep 17 00:00:00 2001
From: alexlamsl <alexlamsl@gmail.com>
Date: Sun, 21 Jan 2018 15:58:14 +0800
Subject: [PATCH 28/28] allow duplicate property names in object literals for
 ES6+

---
 lib/compress.js             |  2 +-
 test/compress/properties.js | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/lib/compress.js b/lib/compress.js
index 2fd8c4fb..2db9e03a 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1865,7 +1865,7 @@ merge(Compressor.prototype, {
                 }
                 if (prop instanceof AST_Node) break;
                 prop = "" + prop;
-                if (compressor.has_directive("use strict")) {
+                if (compressor.option("ecma") < 6 && compressor.has_directive("use strict")) {
                     if (!all(def.value.properties, function(node) {
                         return node.key != prop && node.key.name != prop;
                     })) break;
diff --git a/test/compress/properties.js b/test/compress/properties.js
index bb94d4d2..515d3125 100644
--- a/test/compress/properties.js
+++ b/test/compress/properties.js
@@ -1865,3 +1865,32 @@ issue_2816: {
     }
     expect_stdout: "3 2 4"
 }
+
+issue_2816_ecma6: {
+    options = {
+        ecma: "6",
+        join_vars: true,
+    }
+    input: {
+        "use strict";
+        var o = {
+            a: 1
+        };
+        o.b = 2;
+        o.a = 3;
+        o.c = 4;
+        console.log(o.a, o.b, o.c);
+    }
+    expect: {
+        "use strict";
+        var o = {
+            a: 1,
+            b: 2,
+            a: 3,
+            c: 4
+        };
+        console.log(o.a, o.b, o.c);
+    }
+    expect_stdout: "3 2 4"
+    node_version: ">=4"
+}