v3.12.5

fixes #4570

.github/ISSUE_TEMPLATE.md

@@ -1,25 +0,0 @@
-**Bug report or feature request?**
-
-<!-- Note: sub-optimal but correct code is not a bug -->
-
-**Uglify version (`uglifyjs -V`)**
-
-**JavaScript input**
-
-<!--
-    A complete parsable JS program exhibiting the issue with
-    UglifyJS alone - without third party tools or libraries.
-    Ideally the input should be as small as possible.
-    Post a link to a gist if necessary.
-
-    Issues without a reproducible test case will be closed.
--->
-
-**The `uglifyjs` CLI command executed or `minify()` options used.**
-
-**JavaScript output or error produced.**
-
-<!--
-    Note: `uglify-js` only supports JavaScript.
-    Those wishing to minify ES6+ should transpile first.
--->

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,51 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+<!-- Note: sub-optimal but correct code is not a bug -->
+
+**Uglify version (`uglifyjs -V`)**
+
+**JavaScript input**
+
+<!--
+A complete parsable JS program exhibiting the issue with UglifyJS alone
+- without third party tools or libraries.
+
+Ideally the input should be as small as possible, but may be large if isolating
+the problem proves to be difficult. The most important thing is that the
+standalone program reliably exhibits the bug when minified. Provide a link to a
+gist if necessary.
+
+Solely providing minified output without the original uglify JS input is not
+useful in determining the cause of the problem. Issues without a reproducible
+test case will be closed.
+-->
+
+**The `uglifyjs` CLI command executed or `minify()` options used.**
+
+<!--
+Command-line or API call to UglifyJS without third party tools or libraries.
+
+For users using bundlers or transpilers, you may be able to gather the required
+information through setting the `UGLIFY_BUG_REPORT` environment variable:
+
+    export UGLIFY_BUG_REPORT=1      (bash)
+    set UGLIFY_BUG_REPORT=1         (Command Prompt)
+    $Env:UGLIFY_BUG_REPORT=1        (PowerShell)
+
+before running your usual build process. The resulting "minified" output should
+contain the necessary details for this report.
+-->
+
+**JavaScript output or error produced.**
+
+<!--
+Only minified code that produces different output (or error) from the original
+upon execution would be considered a bug.
+-->

.github/workflows/ci.yml

@@ -7,13 +7,13 @@ jobs:
   test:
     strategy:
       matrix:
-        node: [ "0.8", "0.10", "0.12", "4", "6", "8", "10", "12", latest ]
+        node: [ '0.8', '0.10', '0.12', '4', '6', '8', '10', '12', latest ]
         os: [ ubuntu-latest, windows-latest ]
         script: [ compress, mocha, release/benchmark, release/jetstream ]
         exclude:
-          - node: "0.8"
+          - node: '0.8'
             script: release/benchmark
-          - node: "0.8"
+          - node: '0.8'
             script: release/jetstream
     name: ${{ matrix.node }} ${{ matrix.os }} ${{ matrix.script }}
     runs-on: ${{ matrix.os }}
@@ -29,7 +29,7 @@ jobs:
       - name: Perform tests
         shell: bash
         run: |
-          git clone --branch v1.5.4 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs
+          git clone --branch v1.6.0 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs
           while ! timeout 60 bash -c '. ~/.nvs/nvs.sh add $NODE && nvs use $NODE'; do
             cd ~/.nvs
             while !(git clean -xdf); do echo "'git clean' failed - retrying..."; done

.github/workflows/ufuzz.yml

@@ -2,7 +2,7 @@ name: Fuzzing
 on:
   pull_request:
   schedule:
-    - cron: "*/5 * * * *"
+    - cron: '*/5 * * * *'
 env:
   BASE_URL: https://api.github.com/repos/${{ github.repository }}
   CAUSE: ${{ github.event_name }}
@@ -13,22 +13,39 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ ubuntu-latest, windows-latest ]
-    name: ${{ matrix.os }}
+        include:
+          - node: latest
+            os: macos-latest
+          - node: '8'
+            os: ubuntu-latest
+          - node: '8'
+            os: ubuntu-latest
+          - node: '8'
+            os: windows-latest
+          - node: '8'
+            os: windows-latest
+    name: ${{ matrix.node }} ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
+    env:
+      NODE: ${{ matrix.node }}
     steps:
       - uses: actions/checkout@v2
+      - name: Install GNU Core Utilities
+        if: ${{ startsWith(matrix.os, 'macos') }}
+        shell: bash
+        run: |
+          brew install coreutils
       - name: Perform fuzzing
         shell: bash
         run: |
-          git clone --branch v1.5.4 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs
-          while ! timeout 60 bash -c '. ~/.nvs/nvs.sh add 8 && nvs use 8'; do
+          git clone --branch v1.6.0 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs
+          while ! timeout 60 bash -c '. ~/.nvs/nvs.sh add $NODE && nvs use $NODE'; do
             cd ~/.nvs
             while !(git clean -xdf); do echo "'git clean' failed - retrying..."; done
             cd -
           done
           . ~/.nvs/nvs.sh --version
-          nvs use 8
+          nvs use $NODE
           node --version
           npm config set audit false
           npm config set optional false

README.md

@@ -135,6 +135,10 @@ a double dash to prevent input files being used as option arguments:
                                        `//# sourceMappingURL`.
     --timings                   Display operations run time on STDERR.
     --toplevel                  Compress and/or mangle variables in top level scope.
+    --v8                        Support non-standard Chrome & Node.js
+                                Equivalent to setting `v8: true` in `minify()`
+                                for `mangle` and `output` options.
+                                By default UglifyJS will not try to be v8-proof.
     --verbose                   Print diagnostic messages.
     --warn                      Print warning messages.
     --webkit                    Support non-standard Safari/Webkit.
@@ -522,6 +526,8 @@ if (result.error) throw result.error;
 - `toplevel` (default `false`) -- set to `true` if you wish to enable top level
   variable and function name mangling and to drop unused variables and functions.
 
+- `v8` (default `false`) -- enable workarounds for Chrome & Node.js bugs.
+
 - `warnings` (default `false`) — pass `true` to return compressor warnings
   in `result.warnings`. Use the value `"verbose"` for more detailed warnings.
 
@@ -621,7 +627,11 @@ to be `false` and all symbol names will be omitted.
 - `arguments` (default: `true`) -- replace `arguments[index]` with function
   parameter name whenever possible.
 
-- `assignments` (default: `true`) -- apply optimizations to assignment expressions.
+- `arrows` (default: `true`) -- apply optimizations to arrow functions
+
+- `assignments` (default: `true`) -- apply optimizations to assignment expressions
+
+- `awaits` (default: `true`) -- apply optimizations to `await` expressions
 
 - `booleans` (default: `true`) -- various optimizations for boolean context,
   for example `!!a ? b : c → a ? b : c`
@@ -638,6 +648,8 @@ to be `false` and all symbol names will be omitted.
 
 - `dead_code` (default: `true`) -- remove unreachable code
 
+- `default_values` (default: `true`) -- drop overshadowed default values
+
 - `directives` (default: `true`) -- remove redundant or non-standard directives
 
 - `drop_console` (default: `false`) -- Pass `true` to discard calls to
@@ -683,13 +695,9 @@ to be `false` and all symbol names will be omitted.
 
 - `join_vars` (default: `true`) -- join consecutive `var` statements
 
-- `keep_fargs` (default: `strict`) -- Discard unused function arguments. Code
-  which relies on `Function.length` will break if this is done indiscriminately,
-  i.e. when passing `true`. Pass `false` to always retain function arguments.
-
-- `keep_fnames` (default: `false`) -- Pass `true` to prevent the
-  compressor from discarding function names.  Useful for code relying on
-  `Function.prototype.name`. See also: the `keep_fnames` [mangle option](#mangle-options).
+- `keep_fargs` (default: `false`) -- discard unused function arguments except
+  when unsafe to do so, e.g. code which relies on `Function.prototype.length`.
+  Pass `true` to always retain function arguments.
 
 - `keep_infinity` (default: `false`) -- Pass `true` to prevent `Infinity` from
   being compressed into `1/0`, which may cause performance issues on Chrome.
@@ -739,6 +747,8 @@ to be `false` and all symbol names will be omitted.
 - `reduce_vars` (default: `true`) -- Improve optimization on variables assigned with and
   used as constant values.
 
+- `rests` (default: `true`) -- apply optimizations to rest parameters
+
 - `sequences` (default: `true`) -- join consecutive simple statements using the
   comma operator.  May be set to a positive integer to specify the maximum number
   of consecutive comma sequences that will be generated. If this option is set to
@@ -753,20 +763,20 @@ to be `false` and all symbol names will be omitted.
   annotation `/*@__PURE__*/` or `/*#__PURE__*/` immediately precedes the call. For
   example: `/*@__PURE__*/foo();`
 
-- `spread` (default: `true`) -- flatten spread expressions.
+- `spreads` (default: `true`) -- flatten spread expressions.
 
 - `strings` (default: `true`) -- compact string concatenations.
 
 - `switches` (default: `true`) -- de-duplicate and remove unreachable `switch` branches
 
-- `toplevel` (default: `false`) -- drop unreferenced functions (`"funcs"`) and/or
-  variables (`"vars"`) in the top level scope (`false` by default, `true` to drop
-  both unreferenced functions and variables)
-
 - `top_retain` (default: `null`) -- prevent specific toplevel functions and
   variables from `unused` removal (can be array, comma-separated, RegExp or
   function. Implies `toplevel`)
 
+- `toplevel` (default: `false`) -- drop unreferenced functions (`"funcs"`) and/or
+  variables (`"vars"`) in the top level scope (`false` by default, `true` to drop
+  both unreferenced functions and variables)
+
 - `typeofs` (default: `true`) -- Transforms `typeof foo == "undefined"` into
   `foo === void 0`.  Note: recommend to set this value to `false` for IE10 and
   earlier versions due to known issues.
@@ -803,10 +813,6 @@ to be `false` and all symbol names will be omitted.
 - `eval` (default `false`) -- Pass `true` to mangle names visible in scopes
   where `eval` or `with` are used.
 
-- `keep_fnames` (default `false`) -- Pass `true` to not mangle function names.
-  Useful for code relying on `Function.prototype.name`. See also: the `keep_fnames`
-  [compress option](#compress-options).
-
 - `reserved` (default `[]`) -- Pass an array of identifiers that should be
   excluded from mangling. Example: `["foo", "bar"]`.
 
@@ -873,7 +879,7 @@ can pass additional arguments that control the code output:
   comments, `"some"` to preserve multi-line comments that contain `@cc_on`,
   `@license`, or `@preserve` (case-insensitive), a regular expression string
   (e.g. `/^!/`), or a function which returns `boolean`, e.g.
-  ```js
+  ```javascript
   function(node, comment) {
       return comment.value.indexOf("@type " + node.TYPE) >= 0;
   }
@@ -919,8 +925,6 @@ can pass additional arguments that control the code output:
 
 - `shebang` (default `true`) -- preserve shebang `#!` in preamble (bash scripts)
 
-- `v8` (default `false`) -- enable workarounds for Chrome & Node.js bugs
-
 - `width` (default `80`) -- only takes effect when beautification is on, this
   specifies an (orientative) line width that the beautifier will try to
   obey.  It refers to the width of the line text (excluding indentation).
@@ -1146,7 +1150,7 @@ To enable fast minify mode from the CLI use:
 uglifyjs file.js -m
 ```
 To enable fast minify mode with the API use:
-```js
+```javascript
 UglifyJS.minify(code, { compress: false, mangle: true });
 ```
 
@@ -1178,10 +1182,10 @@ To allow for better optimizations, the compiler makes various assumptions:
   `Object.defineProperty()`, `Object.defineProperties()`, `Object.freeze()`,
   `Object.preventExtensions()` or `Object.seal()`).
 - Earlier versions of JavaScript will throw `SyntaxError` with the following:
-  ```js
+  ```javascript
   ({
-    p: 42,
-    get p() {},
+      p: 42,
+      get p() {},
   });
   // SyntaxError: Object literal may not have data and accessor property with
   //              the same name
@@ -1191,7 +1195,7 @@ To allow for better optimizations, the compiler makes various assumptions:
   versions of Chrome and Node.js may be altered.
 - When `toplevel` is enabled, UglifyJS effectively assumes input code is wrapped
   within `function(){ ... }`, thus forbids aliasing of declared global variables:
-  ```js
+  ```javascript
   A = "FAIL";
   var B = "FAIL";
   // can be `global`, `self`, `window` etc.
@@ -1211,7 +1215,7 @@ To allow for better optimizations, the compiler makes various assumptions:
   suppress those errors.
 - Earlier versions of Chrome and Node.js will throw `ReferenceError` with the
   following:
-  ```js
+  ```javascript
   var a;
   try {
       throw 42;
@@ -1224,20 +1228,29 @@ To allow for better optimizations, the compiler makes various assumptions:
   ```
   UglifyJS may modify the input which in turn may suppress those errors.
 - Later versions of JavaScript will throw `SyntaxError` with the following:
-  ```js
+  ```javascript
   a => {
-    let a;
+      let a;
   };
   // SyntaxError: Identifier 'a' has already been declared
   ```
   UglifyJS may modify the input which in turn may suppress those errors.
 - Later versions of JavaScript will throw `SyntaxError` with the following:
-  ```js
+  ```javascript
   try {
-    // ...
+      // ...
   } catch ({ message: a }) {
-    var a;
+      var a;
   }
   // SyntaxError: Identifier 'a' has already been declared
   ```
   UglifyJS may modify the input which in turn may suppress those errors.
+- Some versions of Chrome and Node.js will throw `ReferenceError` with the
+  following:
+  ```javascript
+  console.log(((a, b = function() {
+      return a;
+      // ReferenceError: a is not defined
+  }()) => b)());
+  ```
+  UglifyJS may modify the input which in turn may suppress those errors.

bin/uglifyjs

@@ -3,7 +3,7 @@
 
 "use strict";
 
-require("../tools/exit");
+require("../tools/tty");
 
 var fs = require("fs");
 var info = require("../package.json");
@@ -265,7 +265,7 @@ if (paths.length) {
     process.stdin.on("data", function(chunk) {
         chunks.push(chunk);
     }).on("end", function() {
-        files = [ chunks.join("") ];
+        files = { STDIN: chunks.join("") };
         run();
     });
     process.stdin.resume();

lib/ast.js

@@ -160,6 +160,8 @@ var restore_transforms = [];
 AST_Node.enable_validation = function() {
     AST_Node.disable_validation();
     (function validate_transform(ctor) {
+        ctor.SUBCLASSES.forEach(validate_transform);
+        if (!HOP(ctor.prototype, "transform")) return;
         var transform = ctor.prototype.transform;
         ctor.prototype.transform = function(tw, in_list) {
             var node = transform.call(this, tw, in_list);
@@ -173,7 +175,6 @@ AST_Node.enable_validation = function() {
         restore_transforms.push(function() {
             ctor.prototype.transform = transform;
         });
-        ctor.SUBCLASSES.forEach(validate_transform);
     })(this);
 };
 
@@ -207,13 +208,23 @@ var AST_EmptyStatement = DEFNODE("EmptyStatement", null, {
     $documentation: "The empty statement (empty block or simply a semicolon)"
 }, AST_Statement);
 
-function must_be_expression(node, prop) {
-    if (!(node[prop] instanceof AST_Node)) throw new Error(prop + " must be AST_Node");
-    if (node[prop] instanceof AST_Hole) throw new Error(prop + " cannot be AST_Hole");
-    if (node[prop] instanceof AST_Spread) throw new Error(prop + " cannot be AST_Spread");
-    if (node[prop] instanceof AST_Statement && !is_function(node[prop])) {
-        throw new Error(prop + " cannot be AST_Statement");
+function validate_expression(value, prop, multiple, allow_spread, allow_hole) {
+    multiple = multiple ? "contain" : "be";
+    if (!(value instanceof AST_Node)) throw new Error(prop + " must " + multiple + " AST_Node");
+    if (value instanceof AST_DefaultValue) throw new Error(prop + " cannot " + multiple + " AST_DefaultValue");
+    if (value instanceof AST_Destructured) throw new Error(prop + " cannot " + multiple + " AST_Destructured");
+    if (value instanceof AST_Hole && !allow_hole) throw new Error(prop + " cannot " + multiple + " AST_Hole");
+    if (value instanceof AST_Spread && !allow_spread) throw new Error(prop + " cannot " + multiple + " AST_Spread");
+    if (value instanceof AST_Statement && !is_function(value)) {
+        throw new Error(prop + " cannot " + multiple + " AST_Statement");
     }
+    if (value instanceof AST_SymbolDeclaration) {
+        throw new Error(prop + " cannot " + multiple + " AST_SymbolDeclaration");
+    }
+}
+
+function must_be_expression(node, prop) {
+    validate_expression(node[prop], prop);
 }
 
 var AST_SimpleStatement = DEFNODE("SimpleStatement", "body", {
@@ -502,14 +513,19 @@ var AST_Toplevel = DEFNODE("Toplevel", "globals", {
     }
 }, AST_Scope);
 
-var AST_Lambda = DEFNODE("Lambda", "argnames length_read uses_arguments", {
+var AST_Lambda = DEFNODE("Lambda", "argnames length_read rest uses_arguments", {
     $documentation: "Base class for functions",
     $propdoc: {
-        argnames: "[(AST_Destructured|AST_SymbolFunarg)*] array of function arguments and/or destructured literals",
+        argnames: "[(AST_DefaultValue|AST_Destructured|AST_SymbolFunarg)*] array of function arguments and/or destructured literals",
+        rest: "[(AST_Destructured|AST_SymbolFunarg)?] rest parameter, or null if absent",
         uses_arguments: "[boolean/S] tells whether this function accesses the arguments array",
     },
     each_argname: function(visit) {
         var tw = new TreeWalker(function(node) {
+            if (node instanceof AST_DefaultValue) {
+                node.name.walk(tw);
+                return true;
+            }
             if (node instanceof AST_DestructuredKeyVal) {
                 node.value.walk(tw);
                 return true;
@@ -519,6 +535,7 @@ var AST_Lambda = DEFNODE("Lambda", "argnames length_read uses_arguments", {
         this.argnames.forEach(function(argname) {
             argname.walk(tw);
         });
+        if (this.rest) this.rest.walk(tw);
     },
     walk: function(visitor) {
         var node = this;
@@ -527,6 +544,7 @@ var AST_Lambda = DEFNODE("Lambda", "argnames length_read uses_arguments", {
             node.argnames.forEach(function(argname) {
                 argname.walk(visitor);
             });
+            if (node.rest) node.rest.walk(visitor);
             walk_body(node, visitor);
         });
     },
@@ -534,7 +552,10 @@ var AST_Lambda = DEFNODE("Lambda", "argnames length_read uses_arguments", {
         this.argnames.forEach(function(node) {
             validate_destructured(node, function(node) {
                 if (!(node instanceof AST_SymbolFunarg)) throw new Error("argnames must be AST_SymbolFunarg[]");
-            });
+            }, true);
+        });
+        if (this.rest != null) validate_destructured(this.rest, function(node) {
+            if (!(node instanceof AST_SymbolFunarg)) throw new Error("rest must be AST_SymbolFunarg");
         });
     },
 }, AST_Scope);
@@ -546,8 +567,20 @@ var AST_Accessor = DEFNODE("Accessor", null, {
     },
 }, AST_Lambda);
 
+function is_arrow(node) {
+    return node instanceof AST_AsyncArrow || node instanceof AST_Arrow;
+}
+
 function is_function(node) {
-    return node instanceof AST_Arrow || node instanceof AST_AsyncFunction || node instanceof AST_Function;
+    return is_arrow(node) || node instanceof AST_AsyncFunction || node instanceof AST_Function;
+}
+
+function walk_lambda(node, tw) {
+    if (is_arrow(node) && node.value) {
+        node.value.walk(tw);
+    } else {
+        walk_body(node, tw);
+    }
 }
 
 var AST_Arrow = DEFNODE("Arrow", "inlined value", {
@@ -561,6 +594,7 @@ var AST_Arrow = DEFNODE("Arrow", "inlined value", {
             node.argnames.forEach(function(argname) {
                 argname.walk(visitor);
             });
+            if (node.rest) node.rest.walk(visitor);
             if (node.value) {
                 node.value.walk(visitor);
             } else {
@@ -579,9 +613,38 @@ var AST_Arrow = DEFNODE("Arrow", "inlined value", {
 }, AST_Lambda);
 
 function is_async(node) {
-    return node instanceof AST_AsyncDefun || node instanceof AST_AsyncFunction;
+    return node instanceof AST_AsyncArrow || node instanceof AST_AsyncDefun || node instanceof AST_AsyncFunction;
 }
 
+var AST_AsyncArrow = DEFNODE("AsyncArrow", "inlined value", {
+    $documentation: "An asynchronous arrow function expression",
+    $propdoc: {
+        value: "[AST_Node?] simple return expression, or null if using function body.",
+    },
+    walk: function(visitor) {
+        var node = this;
+        visitor.visit(node, function() {
+            node.argnames.forEach(function(argname) {
+                argname.walk(visitor);
+            });
+            if (node.rest) node.rest.walk(visitor);
+            if (node.value) {
+                node.value.walk(visitor);
+            } else {
+                walk_body(node, visitor);
+            }
+        });
+    },
+    _validate: function() {
+        if (this.name != null) throw new Error("name must be null");
+        if (this.uses_arguments) throw new Error("uses_arguments must be false");
+        if (this.value != null) {
+            must_be_expression(this, "value");
+            if (this.body.length) throw new Error("body must be empty if value exists");
+        }
+    },
+}, AST_Lambda);
+
 var AST_AsyncFunction = DEFNODE("AsyncFunction", "inlined name", {
     $documentation: "An asynchronous function expression",
     $propdoc: {
@@ -838,7 +901,6 @@ var AST_Const = DEFNODE("Const", null, {
             validate_destructured(node.name, function(node) {
                 if (!(node instanceof AST_SymbolConst)) throw new Error("name must be AST_SymbolConst");
             });
-            if (node.value != null) must_be_expression(node, "value");
         });
     },
 }, AST_Definitions);
@@ -851,7 +913,6 @@ var AST_Let = DEFNODE("Let", null, {
             validate_destructured(node.name, function(node) {
                 if (!(node instanceof AST_SymbolLet)) throw new Error("name must be AST_SymbolLet");
             });
-            if (node.value != null) must_be_expression(node, "value");
         });
     },
 }, AST_Definitions);
@@ -864,7 +925,6 @@ var AST_Var = DEFNODE("Var", null, {
             validate_destructured(node.name, function(node) {
                 if (!(node instanceof AST_SymbolVar)) throw new Error("name must be AST_SymbolVar");
             });
-            if (node.value != null) must_be_expression(node, "value");
         });
     },
 }, AST_Definitions);
@@ -873,7 +933,7 @@ var AST_VarDef = DEFNODE("VarDef", "name value", {
     $documentation: "A variable declaration; only appears in a AST_Definitions node",
     $propdoc: {
         name: "[AST_Destructured|AST_SymbolVar] name of the variable",
-        value: "[AST_Node?] initializer, or null of there's no initializer"
+        value: "[AST_Node?] initializer, or null of there's no initializer",
     },
     walk: function(visitor) {
         var node = this;
@@ -882,18 +942,34 @@ var AST_VarDef = DEFNODE("VarDef", "name value", {
             if (node.value) node.value.walk(visitor);
         });
     },
+    _validate: function() {
+        if (this.value != null) must_be_expression(this, "value");
+    },
 });
 
 /* -----[ OTHER ]----- */
 
+var AST_DefaultValue = DEFNODE("DefaultValue", "name value", {
+    $documentation: "A default value declaration",
+    $propdoc: {
+        name: "[AST_Destructured|AST_SymbolDeclaration] name of the variable",
+        value: "[AST_Node] value to assign if variable is `undefined`",
+    },
+    walk: function(visitor) {
+        var node = this;
+        visitor.visit(node, function() {
+            node.name.walk(visitor);
+            node.value.walk(visitor);
+        });
+    },
+    _validate: function() {
+        must_be_expression(this, "value");
+    },
+});
+
 function must_be_expressions(node, prop, allow_spread, allow_hole) {
     node[prop].forEach(function(node) {
-        if (!(node instanceof AST_Node)) throw new Error(prop + " must be AST_Node[]");
-        if (!allow_hole && node instanceof AST_Hole) throw new Error(prop + " cannot be AST_Hole");
-        if (!allow_spread && node instanceof AST_Spread) throw new Error(prop + " cannot be AST_Spread");
-        if (node instanceof AST_Statement && !is_function(node)) {
-            throw new Error(prop + " cannot contain AST_Statement");
-        }
+        validate_expression(node, prop, true, allow_spread, allow_hole);
     });
 }
 
@@ -1048,7 +1124,7 @@ var AST_Binary = DEFNODE("Binary", "operator left right", {
         });
     },
     _validate: function() {
-        must_be_expression(this, "left");
+        if (!(this instanceof AST_Assign)) must_be_expression(this, "left");
         if (typeof this.operator != "string") throw new Error("operator must be string");
         must_be_expression(this, "right");
     },
@@ -1127,24 +1203,31 @@ var AST_Array = DEFNODE("Array", "elements", {
     },
 });
 
-var AST_Destructured = DEFNODE("Destructured", null, {
+var AST_Destructured = DEFNODE("Destructured", "rest", {
     $documentation: "Base class for destructured literal",
+    $propdoc: {
+        rest: "[(AST_Destructured|AST_SymbolDeclaration|AST_SymbolRef)?] rest parameter, or null if absent",
+    },
 });
 
-function validate_destructured(node, check) {
-    if (node instanceof AST_DestructuredArray) return node.elements.forEach(function(node) {
-        if (!(node instanceof AST_Hole)) validate_destructured(node, check);
-    });
-    if (node instanceof AST_DestructuredObject) return node.properties.forEach(function(prop) {
-        validate_destructured(prop.value, check);
-    });
+function validate_destructured(node, check, allow_default) {
+    if (node instanceof AST_DefaultValue && allow_default) return validate_destructured(node.name, check);
+    if (node instanceof AST_Destructured) {
+        if (node.rest != null) validate_destructured(node.rest, check);
+        if (node instanceof AST_DestructuredArray) return node.elements.forEach(function(node) {
+            if (!(node instanceof AST_Hole)) validate_destructured(node, check, true);
+        });
+        if (node instanceof AST_DestructuredObject) return node.properties.forEach(function(prop) {
+            validate_destructured(prop.value, check, true);
+        });
+    }
     check(node);
 }
 
 var AST_DestructuredArray = DEFNODE("DestructuredArray", "elements", {
     $documentation: "A destructured array literal",
     $propdoc: {
-        elements: "[AST_Node*] array of elements",
+        elements: "[(AST_DefaultValue|AST_Destructured|AST_SymbolDeclaration|AST_SymbolRef)*] array of elements",
     },
     walk: function(visitor) {
         var node = this;
@@ -1152,6 +1235,7 @@ var AST_DestructuredArray = DEFNODE("DestructuredArray", "elements", {
             node.elements.forEach(function(element) {
                 element.walk(visitor);
             });
+            if (node.rest) node.rest.walk(visitor);
         });
     },
 }, AST_Destructured);
@@ -1160,7 +1244,7 @@ var AST_DestructuredKeyVal = DEFNODE("DestructuredKeyVal", "key value", {
     $documentation: "A key: value destructured property",
     $propdoc: {
         key: "[string|AST_Node] property name.  For computed property this is an AST_Node.",
-        value: "[AST_Node] property value",
+        value: "[AST_DefaultValue|AST_Destructured|AST_SymbolDeclaration|AST_SymbolRef] property value",
     },
     walk: function(visitor) {
         var node = this;
@@ -1174,7 +1258,7 @@ var AST_DestructuredKeyVal = DEFNODE("DestructuredKeyVal", "key value", {
             if (!(this.key instanceof AST_Node)) throw new Error("key must be string or AST_Node");
             must_be_expression(this, "key");
         }
-        must_be_expression(this, "value");
+        if (!(this.value instanceof AST_Node)) throw new Error("value must be AST_Node");
     },
 });
 
@@ -1189,6 +1273,7 @@ var AST_DestructuredObject = DEFNODE("DestructuredObject", "properties", {
             node.properties.forEach(function(prop) {
                 prop.walk(visitor);
             });
+            if (node.rest) node.rest.walk(visitor);
         });
     },
     _validate: function() {
@@ -1318,7 +1403,7 @@ var AST_Label = DEFNODE("Label", "references", {
     }
 }, AST_Symbol);
 
-var AST_SymbolRef = DEFNODE("SymbolRef", "fixed in_arg", {
+var AST_SymbolRef = DEFNODE("SymbolRef", "fixed in_arg redef", {
     $documentation: "Reference to some symbol (not definition/declaration)",
 }, AST_Symbol);
 

lib/minify.js

@@ -87,6 +87,7 @@ function minify(files, options) {
             sourceMap: false,
             timings: false,
             toplevel: false,
+            v8: false,
             validate: false,
             warnings: false,
             webkit: false,
@@ -102,6 +103,7 @@ function minify(files, options) {
         set_shorthand("ie8", options, [ "compress", "mangle", "output" ]);
         set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
         set_shorthand("toplevel", options, [ "compress", "mangle" ]);
+        set_shorthand("v8", options, [ "mangle", "output" ]);
         set_shorthand("webkit", options, [ "mangle", "output" ]);
         var quoted_props;
         if (options.mangle) {
@@ -113,6 +115,7 @@ function minify(files, options) {
                 properties: false,
                 reserved: [],
                 toplevel: false,
+                v8: false,
                 webkit: false,
             }, true);
             if (options.mangle.properties) {

lib/output.js

@@ -692,7 +692,7 @@ function OutputStream(options) {
             // [ 1, (2, 3), 4 ] ==> [ 1, 3, 4 ]
         return p instanceof AST_Array
             // () => (foo, bar)
-            || p instanceof AST_Arrow && p.value === this
+            || is_arrow(p) && p.value === this
             // await (foo, bar)
             || p instanceof AST_Await
             // 1 + (2, 3) + 4 ==> 8
@@ -702,6 +702,8 @@ function OutputStream(options) {
             // (false, true) ? (a = 10, b = 20) : (c = 30)
             // ==> 20 (side effect, set a := 10 and b := 20)
             || p instanceof AST_Conditional
+            // [ a = (1, 2) ] = [] ==> a == 2
+            || p instanceof AST_DefaultValue
             // { [(1, 2)]: 3 }[2] ==> 3
             // { foo: (1, 2) }.foo ==> 2
             || p instanceof AST_DestructuredKeyVal
@@ -811,6 +813,9 @@ function OutputStream(options) {
         // ({ p: a } = o);
         if (this.left instanceof AST_DestructuredObject) return needs_parens_obj(output);
     });
+    PARENS(AST_AsyncArrow, function(output) {
+        return needs_parens_assign_cond(this, output);
+    });
     PARENS(AST_Conditional, function(output) {
         return needs_parens_assign_cond(this, output);
     });
@@ -990,16 +995,25 @@ function OutputStream(options) {
     });
 
     /* -----[ functions ]----- */
-    DEFPRINT(AST_Arrow, function(output) {
-        var self = this;
-        if (self.argnames.length == 1 && self.argnames[0] instanceof AST_SymbolFunarg) {
-            self.argnames[0].print(output);
-        } else output.with_parens(function() {
+    function print_funargs(self, output) {
+        output.with_parens(function() {
             self.argnames.forEach(function(arg, i) {
                 if (i) output.comma();
                 arg.print(output);
             });
+            if (self.rest) {
+                if (self.argnames.length) output.comma();
+                output.print("...");
+                self.rest.print(output);
+            }
         });
+    }
+    function print_arrow(self, output) {
+        if (self.argnames.length == 1 && self.argnames[0] instanceof AST_SymbolFunarg && !self.rest) {
+            self.argnames[0].print(output);
+        } else {
+            print_funargs(self, output);
+        }
         output.space();
         output.print("=>");
         output.space();
@@ -1008,18 +1022,21 @@ function OutputStream(options) {
         } else {
             print_braced(self, output, true);
         }
+    }
+    DEFPRINT(AST_Arrow, function(output) {
+        print_arrow(this, output);
+    });
+    DEFPRINT(AST_AsyncArrow, function(output) {
+        output.print("async");
+        output.space();
+        print_arrow(this, output);
     });
     function print_lambda(self, output) {
         if (self.name) {
             output.space();
             self.name.print(output);
         }
-        output.with_parens(function() {
-            self.argnames.forEach(function(arg, i) {
-                if (i) output.comma();
-                arg.print(output);
-            });
-        });
+        print_funargs(self, output);
         output.space();
         print_braced(self, output, true);
     }
@@ -1200,7 +1217,7 @@ function OutputStream(options) {
         if (noin) node.walk(new TreeWalker(function(node) {
             if (parens) return true;
             if (node instanceof AST_Binary && node.operator == "in") return parens = true;
-            if (node instanceof AST_Scope && !(node instanceof AST_Arrow && node.value)) return true;
+            if (node instanceof AST_Scope && !(is_arrow(node) && node.value)) return true;
         }));
         node.print(output, parens);
     }
@@ -1218,6 +1235,15 @@ function OutputStream(options) {
         }
     });
 
+    DEFPRINT(AST_DefaultValue, function(output) {
+        var self = this;
+        self.name.print(output);
+        output.space();
+        output.print("=");
+        output.space();
+        self.value.print(output);
+    });
+
     /* -----[ other expressions ]----- */
     function print_call_args(self, output) {
         if (self.expression instanceof AST_Call || self.expression instanceof AST_Lambda) {
@@ -1344,25 +1370,30 @@ function OutputStream(options) {
         } : noop);
     });
     DEFPRINT(AST_DestructuredArray, function(output) {
-        var a = this.elements, len = a.length;
-        output.with_square(len > 0 ? function() {
+        var a = this.elements, len = a.length, rest = this.rest;
+        output.with_square(len || rest ? function() {
             output.space();
             a.forEach(function(exp, i) {
                 if (i) output.comma();
                 exp.print(output);
+            });
+            if (rest) {
+                if (len) output.comma();
+                output.print("...");
+                rest.print(output);
+            } else if (a[len - 1] instanceof AST_Hole) {
                 // If the final element is a hole, we need to make sure it
                 // doesn't look like a trailing comma, by inserting an actual
                 // trailing comma.
-                if (i === len - 1 && exp instanceof AST_Hole)
-                  output.comma();
-            });
+                output.comma();
+            }
             output.space();
         } : noop);
     });
     DEFPRINT(AST_DestructuredKeyVal, print_key_value);
     DEFPRINT(AST_DestructuredObject, function(output) {
-        var props = this.properties;
-        if (props.length > 0) output.with_block(function() {
+        var props = this.properties, len = props.length, rest = this.rest;
+        if (len || rest) output.with_block(function() {
             props.forEach(function(prop, i) {
                 if (i) {
                     output.print(",");
@@ -1371,6 +1402,15 @@ function OutputStream(options) {
                 output.indent();
                 prop.print(output);
             });
+            if (rest) {
+                if (len) {
+                    output.print(",");
+                    output.newline();
+                }
+                output.indent();
+                output.print("...");
+                rest.print(output);
+            }
             output.newline();
         });
         else print_braced_empty(this, output);

lib/parse.js

@@ -737,7 +737,7 @@ function parse($TEXT, options) {
 
     function semicolon(optional) {
         if (is("punc", ";")) next();
-        else if (!optional && !can_insert_semicolon()) expect_token("punc", ";");
+        else if (!optional && !can_insert_semicolon()) expect(";");
     }
 
     function parenthesised() {
@@ -796,13 +796,14 @@ function parse($TEXT, options) {
                     next();
                     return function_(AST_AsyncDefun);
                 }
+                break;
               case "await":
                 if (S.in_async) return simple_statement();
-              default:
-                return is_token(peek(), "punc", ":")
-                    ? labeled_statement()
-                    : simple_statement();
+                break;
             }
+            return is_token(peek(), "punc", ":")
+                ? labeled_statement()
+                : simple_statement();
 
           case "punc":
             switch (S.token.value) {
@@ -1039,36 +1040,74 @@ function parse($TEXT, options) {
     }
 
     function to_funarg(node) {
-        if (node instanceof AST_Array) return new AST_DestructuredArray({
+        if (node instanceof AST_Array) {
+            var rest = null;
+            if (node.elements[node.elements.length - 1] instanceof AST_Spread) {
+                rest = to_funarg(node.elements.pop().expression);
+            }
+            return new AST_DestructuredArray({
+                start: node.start,
+                elements: node.elements.map(to_funarg),
+                rest: rest,
+                end: node.end,
+            });
+        }
+        if (node instanceof AST_Assign) return new AST_DefaultValue({
             start: node.start,
-            elements: node.elements.map(function(node) {
-                return node instanceof AST_Hole ? node : to_funarg(node);
-            }),
-            end: node.end,
-        });
-        if (node instanceof AST_Object) return new AST_DestructuredObject({
-            start: node.start,
-            properties: node.properties.map(function(prop) {
-                if (!(prop instanceof AST_ObjectKeyVal)) token_error(prop.start, "Invalid destructuring assignment");
-                return new AST_DestructuredKeyVal({
-                    start: prop.start,
-                    key: prop.key,
-                    value: to_funarg(prop.value),
-                    end: prop.end,
-                });
-            }),
+            name: to_funarg(node.left),
+            value: node.right,
             end: node.end,
         });
+        if (node instanceof AST_DefaultValue) {
+            node.name = to_funarg(node.name);
+            return node;
+        }
+        if (node instanceof AST_DestructuredArray) {
+            node.elements = node.elements.map(to_funarg);
+            if (node.rest) node.rest = to_funarg(node.rest);
+            return node;
+        }
+        if (node instanceof AST_DestructuredObject) {
+            node.properties.forEach(function(prop) {
+                prop.value = to_funarg(prop.value);
+            });
+            if (node.rest) node.rest = to_funarg(node.rest);
+            return node;
+        }
+        if (node instanceof AST_Hole) return node;
+        if (node instanceof AST_Object) {
+            var rest = null;
+            if (node.properties[node.properties.length - 1] instanceof AST_Spread) {
+                rest = to_funarg(node.properties.pop().expression);
+            }
+            return new AST_DestructuredObject({
+                start: node.start,
+                properties: node.properties.map(function(prop) {
+                    if (!(prop instanceof AST_ObjectKeyVal)) token_error(prop.start, "Invalid destructuring assignment");
+                    return new AST_DestructuredKeyVal({
+                        start: prop.start,
+                        key: prop.key,
+                        value: to_funarg(prop.value),
+                        end: prop.end,
+                    });
+                }),
+                rest: rest,
+                end: node.end,
+            });
+        }
+        if (node instanceof AST_SymbolFunarg) return node;
         if (node instanceof AST_SymbolRef) return new AST_SymbolFunarg(node);
         token_error(node.start, "Invalid arrow parameter");
     }
 
-    function arrow(exprs, start) {
+    function arrow(exprs, start, async) {
         var was_async = S.in_async;
-        S.in_async = false;
+        S.in_async = async;
         var was_funarg = S.in_funarg;
         S.in_funarg = S.in_function;
         var argnames = exprs.map(to_funarg);
+        var rest = exprs.rest || null;
+        if (rest) rest = to_funarg(rest);
         S.in_funarg = was_funarg;
         expect("=>");
         var body, value;
@@ -1094,9 +1133,10 @@ function parse($TEXT, options) {
         S.in_loop = loop;
         S.labels = labels;
         S.in_async = was_async;
-        return new AST_Arrow({
+        return new (async ? AST_AsyncArrow : AST_Arrow)({
             start: start,
             argnames: argnames,
+            rest: rest,
             body: body,
             value: value,
             end: prev(),
@@ -1122,7 +1162,7 @@ function parse($TEXT, options) {
         var was_funarg = S.in_funarg;
         S.in_funarg = S.in_function;
         var argnames = expr_list(")", !options.strict, false, function() {
-            return maybe_destructured(AST_SymbolFunarg);
+            return maybe_default(AST_SymbolFunarg);
         });
         S.in_funarg = was_funarg;
         var loop = S.in_loop;
@@ -1136,6 +1176,7 @@ function parse($TEXT, options) {
         if (S.input.has_directive("use strict")) {
             if (name) strict_verify_symbol(name);
             argnames.forEach(strict_verify_symbol);
+            if (argnames.rest) strict_verify_symbol(argnames.rest);
         }
         S.input.pop_directives_stack();
         --S.in_function;
@@ -1145,6 +1186,7 @@ function parse($TEXT, options) {
         return new ctor({
             name: name,
             argnames: argnames,
+            rest: argnames.rest || null,
             body: body
         });
     };
@@ -1166,7 +1208,7 @@ function parse($TEXT, options) {
         expect("{");
         var a = [];
         while (!is("punc", "}")) {
-            if (is("eof")) expect_token("punc", "}");
+            if (is("eof")) expect("}");
             a.push(statement());
         }
         next();
@@ -1177,7 +1219,7 @@ function parse($TEXT, options) {
         expect("{");
         var a = [], branch, cur, default_branch, tmp;
         while (!is("punc", "}")) {
-            if (is("eof")) expect_token("punc", "}");
+            if (is("eof")) expect("}");
             if (is("keyword", "case")) {
                 if (branch) branch.end = prev();
                 cur = [];
@@ -1393,16 +1435,9 @@ function parse($TEXT, options) {
             }
             unexpected();
         }
-        var ctor;
-        if (is("name", "async") && is_token(peek(), "keyword", "function")) {
+        if (is("keyword", "function")) {
             next();
-            ctor = AST_AsyncFunction;
-        } else if (is("keyword", "function")) {
-            ctor = AST_Function;
-        }
-        if (ctor) {
-            next();
-            var func = function_(ctor);
+            var func = function_(AST_Function);
             func.start = start;
             func.end = prev();
             return subscripts(func, allow_calls);
@@ -1410,6 +1445,30 @@ function parse($TEXT, options) {
         if (is("name")) {
             var sym = _make_symbol(AST_SymbolRef, start);
             next();
+            if (sym.name == "async") {
+                if (is("keyword", "function")) {
+                    next();
+                    var func = function_(AST_AsyncFunction);
+                    func.start = start;
+                    func.end = prev();
+                    return subscripts(func, allow_calls);
+                }
+                if (is("name")) {
+                    start = S.token;
+                    sym = _make_symbol(AST_SymbolRef, start);
+                    next();
+                    return arrow([ sym ], start, true);
+                }
+                if (is("punc", "(")) {
+                    var call = subscripts(sym, allow_calls);
+                    if (!is("punc", "=>")) return call;
+                    var args = call.args;
+                    if (args[args.length - 1] instanceof AST_Spread) {
+                        args.rest = args.pop().expression;
+                    }
+                    return arrow(args, start, true);
+                }
+            }
             return is("punc", "=>") ? arrow([ sym ], start) : subscripts(sym, allow_calls);
         }
         if (ATOMIC_START_TOKEN[S.token.type]) {
@@ -1426,17 +1485,22 @@ function parse($TEXT, options) {
             if (allow_trailing_comma && is("punc", closing)) break;
             if (allow_empty && is("punc", ",")) {
                 a.push(new AST_Hole({ start: S.token, end: S.token }));
-            } else if (parser === maybe_assign && is("operator", "...")) {
+            } else if (!is("operator", "...")) {
+                a.push(parser());
+            } else if (parser === maybe_assign) {
                 a.push(new AST_Spread({
                     start: S.token,
                     expression: (next(), parser()),
                     end: prev(),
                 }));
             } else {
-                a.push(parser());
+                next();
+                a.rest = parser();
+                if (a.rest instanceof AST_DefaultValue) token_error(a.rest.start, "Invalid rest parameter");
+                break;
             }
         }
-        next();
+        expect(closing);
         return a;
     }
 
@@ -1468,6 +1532,32 @@ function parse($TEXT, options) {
                 }));
                 continue;
             }
+            if (is_token(peek(), "operator", "=")) {
+                var name = as_symbol(AST_SymbolRef);
+                next();
+                a.push(new AST_ObjectKeyVal({
+                    start: start,
+                    key: start.value,
+                    value: new AST_Assign({
+                        start: start,
+                        left: name,
+                        operator: "=",
+                        right: maybe_assign(),
+                        end: prev(),
+                    }),
+                    end: prev(),
+                }));
+                continue;
+            }
+            if (is_token(peek(), "punc", ",") || is_token(peek(), "punc", "}")) {
+                a.push(new AST_ObjectKeyVal({
+                    start: start,
+                    key: start.value,
+                    value: as_symbol(AST_SymbolRef),
+                    end: prev(),
+                }));
+                continue;
+            }
             var key = as_property_key();
             if (is("punc", "(")) {
                 var func_start = S.token;
@@ -1492,15 +1582,6 @@ function parse($TEXT, options) {
                 }));
                 continue;
             }
-            if (is("punc", ",") || is("punc", "}")) {
-                a.push(new AST_ObjectKeyVal({
-                    start: start,
-                    key: key,
-                    value: _make_symbol(AST_SymbolRef, start),
-                    end: prev(),
-                }));
-                continue;
-            }
             if (start.type == "name") switch (key) {
               case "async":
                 key = as_property_key();
@@ -1561,9 +1642,8 @@ function parse($TEXT, options) {
     }
 
     function as_name() {
-        if (!is("name")) expect_token("name");
         var name = S.token.value;
-        next();
+        expect_token("name");
         return name;
     }
 
@@ -1599,17 +1679,19 @@ function parse($TEXT, options) {
         var start = S.token;
         if (is("punc", "[")) {
             next();
+            var elements = expr_list("]", !options.strict, true, function() {
+                return maybe_default(type);
+            });
             return new AST_DestructuredArray({
                 start: start,
-                elements: expr_list("]", !options.strict, true, function() {
-                    return maybe_destructured(type);
-                }),
+                elements: elements,
+                rest: elements.rest || null,
                 end: prev(),
             });
         }
         if (is("punc", "{")) {
             next();
-            var first = true, a = [];
+            var first = true, a = [], rest = null;
             while (!is("punc", "}")) {
                 if (first) first = false; else expect(",");
                 // allow trailing comma
@@ -1621,28 +1703,57 @@ function parse($TEXT, options) {
                     a.push(new AST_DestructuredKeyVal({
                         start: key_start,
                         key: key,
-                        value: maybe_destructured(type),
+                        value: maybe_default(type),
                         end: prev(),
                     }));
                     continue;
                 }
+                if (is("operator", "...")) {
+                    next();
+                    rest = maybe_destructured(type);
+                    break;
+                }
+                var name = as_symbol(type);
+                if (is("operator", "=")) {
+                    next();
+                    name = new AST_DefaultValue({
+                        start: name.start,
+                        name: name,
+                        value: maybe_assign(),
+                        end: prev(),
+                    });
+                }
                 a.push(new AST_DestructuredKeyVal({
                     start: key_start,
                     key: key_start.value,
-                    value: as_symbol(type),
+                    value: name,
                     end: prev(),
                 }));
             }
-            next();
+            expect("}");
             return new AST_DestructuredObject({
                 start: start,
                 properties: a,
+                rest: rest,
                 end: prev(),
             });
         }
         return as_symbol(type);
     }
 
+    function maybe_default(type) {
+        var start = S.token;
+        var name = maybe_destructured(type);
+        if (!is("operator", "=")) return name;
+        next();
+        return new AST_DefaultValue({
+            start: start,
+            name: name,
+            value: maybe_assign(),
+            end: prev(),
+        });
+    }
+
     function mark_pure(call) {
         var start = call.start;
         var comments = start.comments_before;
@@ -1787,22 +1898,47 @@ function parse($TEXT, options) {
 
     function to_destructured(node) {
         if (node instanceof AST_Array) {
+            var rest = null;
+            if (node.elements[node.elements.length - 1] instanceof AST_Spread) {
+                rest = to_destructured(node.elements.pop().expression);
+                if (!(rest instanceof AST_Destructured || is_assignable(rest))) return node;
+            }
             var elements = node.elements.map(to_destructured);
             return all(elements, function(node) {
-                return node instanceof AST_Destructured || node instanceof AST_Hole || is_assignable(node);
+                return node instanceof AST_DefaultValue
+                    || node instanceof AST_Destructured
+                    || node instanceof AST_Hole
+                    || is_assignable(node);
             }) ? new AST_DestructuredArray({
                 start: node.start,
                 elements: elements,
+                rest: rest,
+                end: node.end,
+            }) : node;
+        }
+        if (node instanceof AST_Assign) {
+            var name = to_destructured(node.left);
+            return name instanceof AST_Destructured || is_assignable(name) ? new AST_DefaultValue({
+                start: node.start,
+                name: name,
+                value: node.right,
                 end: node.end,
             }) : node;
         }
         if (!(node instanceof AST_Object)) return node;
+        var rest = null;
+        if (node.properties[node.properties.length - 1] instanceof AST_Spread) {
+            rest = to_destructured(node.properties.pop().expression);
+            if (!(rest instanceof AST_Destructured || is_assignable(rest))) return node;
+        }
         var props = [];
         for (var i = 0; i < node.properties.length; i++) {
             var prop = node.properties[i];
             if (!(prop instanceof AST_ObjectKeyVal)) return node;
             var value = to_destructured(prop.value);
-            if (!(value instanceof AST_Destructured || is_assignable(value))) return node;
+            if (!(value instanceof AST_DefaultValue || value instanceof AST_Destructured || is_assignable(value))) {
+                return node;
+            }
             props.push(new AST_DestructuredKeyVal({
                 start: prop.start,
                 key: prop.key,
@@ -1813,6 +1949,7 @@ function parse($TEXT, options) {
         return new AST_DestructuredObject({
             start: node.start,
             properties: props,
+            rest: rest,
             end: node.end,
         });
     }
@@ -1840,15 +1977,20 @@ function parse($TEXT, options) {
         var start = S.token;
         var exprs = [];
         while (true) {
+            if (maybe_arrow && is("operator", "...")) {
+                next();
+                exprs.rest = maybe_destructured(AST_SymbolFunarg);
+                break;
+            }
             exprs.push(maybe_assign(no_in));
             if (!is("punc", ",")) break;
             next();
             if (maybe_arrow && is("punc", ")") && is_token(peek(), "punc", "=>")) break;
         }
-        return exprs.length == 1 ? exprs[0] : new AST_Sequence({
-            start       : start,
-            expressions : exprs,
-            end         : prev()
+        return exprs.length == 1 && !exprs.rest ? exprs[0] : new AST_Sequence({
+            start: start,
+            expressions: exprs,
+            end: prev(),
         });
     }
 
@@ -1861,7 +2003,9 @@ function parse($TEXT, options) {
 
     if (options.expression) {
         handle_regexp();
-        return expression();
+        var exp = expression();
+        expect_token("eof");
+        return exp;
     }
 
     return function() {

lib/scope.js

@@ -48,7 +48,6 @@ function SymbolDef(id, scope, orig, init) {
     this.global = false;
     this.id = id;
     this.init = init;
-    this.lambda = orig instanceof AST_SymbolLambda;
     this.mangled_name = null;
     this.name = orig.name;
     this.orig = [ orig ];
@@ -120,6 +119,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
                 node.argnames.forEach(function(argname) {
                     argname.walk(tw);
                 });
+                if (node.rest) node.rest.walk(tw);
                 walk_body(node, tw);
             });
             return true;
@@ -221,31 +221,33 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             node.argnames.forEach(function(argname) {
                 argname.walk(tw);
             });
+            if (node.rest) node.rest.walk(tw);
             in_arg.pop();
-            if (node instanceof AST_Arrow && node.value) {
-                node.value.walk(tw);
-            } else {
-                walk_body(node, tw);
-            }
+            walk_lambda(node, tw);
             return true;
         }
         if (node instanceof AST_LoopControl) {
             if (node.label) node.label.thedef.references.push(node);
             return true;
         }
-        // ensure mangling works if `catch` reuses a scope variable
-        if (node instanceof AST_SymbolCatch) {
-            var def = node.definition().redefined();
-            if (def) for (var s = node.scope; s; s = s.parent_scope) {
-                push_uniq(s.enclosed, def);
-                if (s === def.scope) break;
+        if (node instanceof AST_SymbolDeclaration) {
+            if (node instanceof AST_SymbolCatch) {
+                // ensure mangling works if `catch` reuses a scope variable
+                var def = node.definition().redefined();
+                if (def) for (var s = node.scope; s; s = s.parent_scope) {
+                    push_uniq(s.enclosed, def);
+                    if (s === def.scope) break;
+                }
+            } else if (node instanceof AST_SymbolConst) {
+                // ensure compression works if `const` reuses a scope variable
+                var redef = node.definition().redefined();
+                if (redef) redef.const_redefs = true;
             }
-            return true;
-        }
-        // ensure compression works if `const` reuses a scope variable
-        if (node instanceof AST_SymbolConst) {
-            var redef = node.definition().redefined();
-            if (redef) redef.const_redefs = true;
+            if (node.name != "arguments") return true;
+            var parent = node instanceof AST_SymbolVar && tw.parent();
+            if (parent instanceof AST_VarDef && !parent.value) return true;
+            var sym = node.scope.resolve().find_variable("arguments");
+            if (sym && is_arguments(sym)) sym.scope.uses_arguments = 3;
             return true;
         }
         if (node instanceof AST_SymbolRef) {
@@ -265,10 +267,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             }
             if (!sym) {
                 sym = self.def_global(node);
-            } else if (name == "arguments"
-                && sym.orig[0] instanceof AST_SymbolFunarg
-                && !(sym.orig[1] instanceof AST_SymbolFunarg)
-                && !(sym.scope instanceof AST_Arrow)) {
+            } else if (name == "arguments" && is_arguments(sym)) {
                 var parent = tw.parent();
                 if (parent instanceof AST_Assign && parent.left === node
                     || parent instanceof AST_Unary && unary_side_effects[parent.operator]) {
@@ -312,8 +311,9 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         }
         if (node instanceof AST_SymbolLambda) {
             var def = node.thedef;
-            redefine(node, node.scope.parent_scope.resolve());
-            if (typeof node.thedef.init !== "undefined") {
+            if (!redefine(node, node.scope.parent_scope.resolve())) {
+                delete def.defun;
+            } else if (typeof node.thedef.init !== "undefined") {
                 node.thedef.init = false;
             } else if (def.init) {
                 node.thedef.init = def.init;
@@ -322,12 +322,18 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         }
     }));
 
+    function is_arguments(sym) {
+        return sym.orig[0] instanceof AST_SymbolFunarg
+            && !(sym.orig[1] instanceof AST_SymbolFunarg || sym.orig[2] instanceof AST_SymbolFunarg)
+            && !is_arrow(sym.scope);
+    }
+
     function redefine(node, scope) {
         var name = node.name;
         var old_def = node.thedef;
         if (!all(old_def.orig, function(sym) {
             return !(sym instanceof AST_SymbolConst || sym instanceof AST_SymbolLet);
-        })) return;
+        })) return false;
         var new_def = scope.find_variable(name);
         if (new_def) {
             var redef = new_def.redefined();
@@ -342,12 +348,12 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         }
         old_def.defun = new_def.scope;
         old_def.forEach(function(node) {
-            node.redef = true;
+            node.redef = old_def;
             node.thedef = new_def;
             node.reference(options);
         });
-        if (old_def.lambda) new_def.lambda = true;
         if (new_def.undeclared) self.variables.set(name, new_def);
+        return true;
     }
 });
 
@@ -387,6 +393,9 @@ AST_Scope.DEFMETHOD("init_vars", function(parent_scope) {
 AST_Arrow.DEFMETHOD("init_vars", function(parent_scope) {
     init_scope_vars(this, parent_scope);
 });
+AST_AsyncArrow.DEFMETHOD("init_vars", function(parent_scope) {
+    init_scope_vars(this, parent_scope);
+});
 AST_Lambda.DEFMETHOD("init_vars", function(parent_scope) {
     init_scope_vars(this, parent_scope);
     this.uses_arguments = false;
@@ -512,6 +521,7 @@ function _default_mangler_options(options) {
         keep_fnames : false,
         reserved    : [],
         toplevel    : false,
+        v8          : false,
         webkit      : false,
     });
     if (!Array.isArray(options.reserved)) options.reserved = [];
@@ -543,7 +553,7 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
             // lname is incremented when we get to the AST_Label
             var save_nesting = lname;
             descend();
-            lname = save_nesting;
+            if (!options.v8 || !in_label(tw)) lname = save_nesting;
             return true;
         }
         if (node instanceof AST_BlockScope) {
@@ -602,6 +612,7 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
             if (!(sym instanceof AST_SymbolConst)) return false;
             var scope = def.scope.resolve();
             if (def.scope === scope) return false;
+            if (def.scope.parent_scope.find_variable(sym.name)) return false;
             redef = scope.def_variable(sym);
             scope.to_mangle.push(redef);
         }
@@ -616,6 +627,14 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
             sym.thedef = def;
         }
     }
+
+    function in_label(tw) {
+        var level = 0, parent;
+        while (parent = tw.parent(level++)) {
+            if (parent instanceof AST_Block) return parent instanceof AST_Toplevel && !options.toplevel;
+            if (parent instanceof AST_LabeledStatement) return true;
+        }
+    }
 });
 
 AST_Toplevel.DEFMETHOD("find_colliding_names", function(options) {

lib/sourcemap.js

@@ -144,7 +144,9 @@ function SourceMap(options) {
             add(source, gen_line, gen_col, orig_line, orig_col, name);
         } : add,
         setSourceContent: sources_content ? function(source, content) {
-            sources_content[source] = content;
+            if (!(source in sources_content)) {
+                sources_content[source] = content;
+            }
         } : noop,
         toString: function() {
             return JSON.stringify({

lib/transform.js

@@ -126,19 +126,27 @@ TreeTransformer.prototype = new TreeWalker;
         self.name = self.name.transform(tw);
         if (self.value) self.value = self.value.transform(tw);
     });
+    DEF(AST_DefaultValue, function(self, tw) {
+        self.name = self.name.transform(tw);
+        self.value = self.value.transform(tw);
+    });
     DEF(AST_Lambda, function(self, tw) {
         if (self.name) self.name = self.name.transform(tw);
         self.argnames = do_list(self.argnames, tw);
+        if (self.rest) self.rest = self.rest.transform(tw);
         self.body = do_list(self.body, tw);
     });
-    DEF(AST_Arrow, function(self, tw) {
+    function transform_arrow(self, tw) {
         self.argnames = do_list(self.argnames, tw);
+        if (self.rest) self.rest = self.rest.transform(tw);
         if (self.value) {
             self.value = self.value.transform(tw);
         } else {
             self.body = do_list(self.body, tw);
         }
-    });
+    }
+    DEF(AST_Arrow, transform_arrow);
+    DEF(AST_AsyncArrow, transform_arrow);
     DEF(AST_Call, function(self, tw) {
         self.expression = self.expression.transform(tw);
         self.args = do_list(self.args, tw);
@@ -176,6 +184,7 @@ TreeTransformer.prototype = new TreeWalker;
     });
     DEF(AST_DestructuredArray, function(self, tw) {
         self.elements = do_list(self.elements, tw);
+        if (self.rest) self.rest = self.rest.transform(tw);
     });
     DEF(AST_DestructuredKeyVal, function(self, tw) {
         if (self.key instanceof AST_Node) self.key = self.key.transform(tw);
@@ -183,6 +192,7 @@ TreeTransformer.prototype = new TreeWalker;
     });
     DEF(AST_DestructuredObject, function(self, tw) {
         self.properties = do_list(self.properties, tw);
+        if (self.rest) self.rest = self.rest.transform(tw);
     });
     DEF(AST_Object, function(self, tw) {
         self.properties = do_list(self.properties, tw);

lib/utils.js

@@ -241,7 +241,7 @@ function HOP(obj, prop) {
 function first_in_statement(stack, arrow) {
     var node = stack.parent(-1);
     for (var i = 0, p; p = stack.parent(i++); node = p) {
-        if (p instanceof AST_Arrow) {
+        if (is_arrow(p)) {
             return arrow && p.value === node;
         } else if (p instanceof AST_Binary) {
             if (p.left === node) continue;

package.json

@@ -3,7 +3,7 @@
   "description": "JavaScript parser, mangler/compressor and beautifier toolkit",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.12.3",
+  "version": "3.12.5",
   "engines": {
     "node": ">=0.8.0"
   },

test/compress.js

@@ -1,6 +1,6 @@
 "use strict";
 
-require("../tools/exit");
+require("../tools/tty");
 
 var assert = require("assert");
 var child_process = require("child_process");

test/compress/arguments.js

@@ -78,7 +78,7 @@ replace_index_strict: {
     ]
 }
 
-replace_index_keep_fargs: {
+replace_index_drop_fargs_1: {
     options = {
         arguments: true,
         evaluate: true,
@@ -101,6 +101,13 @@ replace_index_keep_fargs: {
             var arguments;
             console.log(arguments[1], arguments["1"], arguments["foo"]);
         })("bar", 42);
+        (function() {
+            var arguments = {
+                1: "foo",
+                foo: "bar",
+            };
+            console.log(arguments[1], arguments["1"], arguments["foo"]);
+        })("bar", 42);
     }
     expect: {
         var arguments = [];
@@ -114,8 +121,15 @@ replace_index_keep_fargs: {
         (function(arguments) {
             console.log(arguments[1], arguments[1], arguments.foo);
         })("bar", 42);
-        (function() {
+        (function(argument_0, argument_1) {
             var arguments;
+            console.log(argument_1, argument_1, arguments.foo);
+        })("bar", 42);
+        (function() {
+            var arguments = {
+                1: "foo",
+                foo: "bar",
+            };
             console.log(arguments[1], arguments[1], arguments.foo);
         })("bar", 42);
     }
@@ -125,10 +139,11 @@ replace_index_keep_fargs: {
         "42 42 undefined",
         "a a undefined",
         "42 42 undefined",
+        "foo foo bar",
     ]
 }
 
-replace_index_keep_fargs_strict: {
+replace_index_drop_fargs_2: {
     options = {
         arguments: true,
         evaluate: true,
@@ -412,7 +427,7 @@ issue_3273_global_strict_reduce_vars: {
     ]
 }
 
-issue_3273_keep_fargs_false: {
+issue_3273_drop_fargs_1: {
     options = {
         arguments: true,
         keep_fargs: false,
@@ -435,10 +450,10 @@ issue_3273_keep_fargs_false: {
     expect_stdout: "1"
 }
 
-issue_3273_keep_fargs_strict: {
+issue_3273_drop_fargs_2: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
     }
     input: {
@@ -633,7 +648,7 @@ issue_3282_2_passes: {
 issue_3420_1: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         console.log(function() {
@@ -655,7 +670,7 @@ issue_3420_1: {
 issue_3420_2: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         var foo = function() {
@@ -675,7 +690,7 @@ issue_3420_2: {
 issue_3420_3: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         "use strict";
@@ -697,7 +712,7 @@ issue_3420_3: {
 issue_3420_4: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         !function() {
@@ -722,7 +737,7 @@ issue_3420_4: {
 issue_3420_5: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         "use strict";
@@ -749,7 +764,7 @@ issue_3420_5: {
 issue_3420_6: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         console.log(function() {
@@ -767,7 +782,7 @@ issue_3420_6: {
 issue_3420_7: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         "use strict";
@@ -811,7 +826,7 @@ issue_4200: {
 issue_4291_1: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         console.log(function() {
@@ -831,7 +846,7 @@ issue_4291_1: {
 issue_4291_2: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         var a = function() {
@@ -855,7 +870,7 @@ issue_4291_2: {
 issue_4397: {
     options = {
         arguments: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         console.log(typeof function() {

test/compress/arrows.js

@@ -419,7 +419,7 @@ collapse_value: {
     options = {
         arrows: true,
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -437,7 +437,7 @@ collapse_value: {
 reduce_iife_1: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -587,3 +587,54 @@ issue_4401: {
     ]
     node_version: ">=4"
 }
+
+issue_4448: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        var A;
+        try {
+            (arguments => {
+                arguments[0];
+            })(A);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        var A;
+        try {
+            (arguments => {
+                arguments[0];
+            })(A);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4476: {
+    options = {
+        arguments: true,
+    }
+    input: {
+        (function(a, b) {
+            (a => {
+                console.log(arguments[0], a);
+            })(b);
+        })("foo", "bar");
+    }
+    expect: {
+        (function(a, b) {
+            (a => {
+                console.log(arguments[0], a);
+            })(b);
+        })("foo", "bar");
+    }
+    expect_stdout: "foo bar"
+    node_version: ">=4"
+}

test/compress/assignments.js

@@ -461,3 +461,17 @@ issue_3949_2: {
     }
     expect_stdout: "100"
 }
+
+issue_4521: {
+    options = {
+        assignments: true,
+        dead_code: true,
+    }
+    input: {
+        var a = (a = 42 | a) ? console.log(a) : 0;
+    }
+    expect: {
+        var a = (a |= 42) ? console.log(a) : 0;
+    }
+    expect_stdout: "42"
+}

test/compress/awaits.js

@@ -1,3 +1,27 @@
+async_arrow: {
+    input: {
+        (async a => console.log(a))("PASS");
+        console.log(typeof (async () => 42)());
+    }
+    expect_exact: '(async a=>console.log(a))("PASS");console.log(typeof(async()=>42)());'
+    expect_stdout: [
+        "PASS",
+        "object",
+    ]
+    node_version: ">=8"
+}
+
+async_label: {
+    input: {
+        (async function() {
+            async: console.log("PASS");
+        })();
+    }
+    expect_exact: '(async function(){async:console.log("PASS")})();'
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
 await_await: {
     input: {
         (async function() {
@@ -32,6 +56,54 @@ defun_name: {
     node_version: ">=8"
 }
 
+drop_fname: {
+    rename = true
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    mangle = {
+        toplevel: true,
+    }
+    input: {
+        async function await() {
+            console.log("PASS");
+        }
+        await();
+    }
+    expect: {
+        (async function() {
+            console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+keep_fname: {
+    options = {
+        keep_fnames: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        async function await() {
+            console.log("PASS");
+        }
+        await();
+    }
+    expect: {
+        async function await() {
+            console.log("PASS");
+        }
+        await();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
 nested_await: {
     input: {
         (async function() {
@@ -92,6 +164,215 @@ dont_inline: {
     node_version: ">=8"
 }
 
+inline_await_1: {
+    options = {
+        awaits: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (async function() {
+            async function f() {
+                await 42;
+            }
+            return await f();
+        })();
+        console.log("PASS");
+    }
+    expect: {
+        (async function() {
+            return await void await 42;
+        })();
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+inline_await_1_trim: {
+    options = {
+        awaits: true,
+        if_return: true,
+        inline: true,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (async function() {
+            async function f() {
+                await 42;
+            }
+            return await f();
+        })();
+        console.log("PASS");
+    }
+    expect: {
+        (async function() {
+            await 0;
+        })();
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+inline_await_2: {
+    options = {
+        awaits: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (async function() {
+            async function f(a) {
+                await a;
+            }
+            return await f(console);
+        })();
+        console.log("PASS");
+    }
+    expect: {
+        (async function() {
+            return await void await console;
+        })();
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+inline_await_2_trim: {
+    options = {
+        awaits: true,
+        if_return: true,
+        inline: true,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (async function() {
+            async function f(a) {
+                await a.log;
+            }
+            return await f(console);
+        })();
+        console.log("PASS");
+    }
+    expect: {
+        (async function() {
+            await console.log;
+        })();
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+inline_await_3: {
+    options = {
+        awaits: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (async function() {
+            async function f(a, b) {
+                return await b(a);
+            }
+            return await f("PASS", console.log);
+        })();
+    }
+    expect: {
+        (async function() {
+            return await (a = "PASS", b = console.log, await b(a));
+            var a, b;
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+inline_await_3_trim: {
+    options = {
+        awaits: true,
+        inline: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (async function() {
+            async function f(a, b) {
+                return await b(a);
+            }
+            return await f("PASS", console.log);
+        })();
+    }
+    expect: {
+        (async function() {
+            return a = "PASS", b = console.log, await b(a);
+            var a, b;
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+await_unary: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        var a;
+        (async function() {
+            a = "PASS";
+            await delete a.p;
+            a = "FAIL";
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a;
+        (async function() {
+            a = "PASS";
+            await delete a.p;
+            a = "FAIL";
+        })();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+await_void: {
+    options = {
+        awaits: true,
+        if_return: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            console.log("PASS");
+            return await void 42;
+        })();
+    }
+    expect: {
+        (async function() {
+            await console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
 evaluate: {
     options = {
         evaluate: true,
@@ -353,7 +634,7 @@ property_access_expression: {
 reduce_iife_1: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -640,3 +921,77 @@ issue_4417: {
     expect_stdout: "undefined"
     node_version: ">=8"
 }
+
+issue_4454_1: {
+    rename = false
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a) {
+            (async function(b = console.log(a)) {})();
+            var await = 42..toString();
+            console.log(await);
+        }
+        f("PASS");
+    }
+    expect: {
+        function f(a) {
+            (async function(b = console.log(a)) {})();
+            var await = 42..toString();
+            console.log(await);
+        }
+        f("PASS");
+    }
+    expect_stdout: [
+        "PASS",
+        "42",
+    ]
+    node_version: ">=8"
+}
+
+issue_4454_2: {
+    rename = true
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a) {
+            (async function(b = console.log(a)) {})();
+            var await = 42..toString();
+            console.log(await);
+        }
+        f("PASS");
+    }
+    expect: {
+        function f(b) {
+            (async function(c = console.log(b)) {})();
+            var b = 42..toString();
+            console.log(b);
+        }
+        f("PASS");
+    }
+    expect_stdout: [
+        "PASS",
+        "42",
+    ]
+    node_version: ">=8"
+}
+
+issue_4534: {
+    options = {
+        arguments: true,
+    }
+    input: {
+        (function(await) {
+            (async () => console.log(arguments[0]))();
+        })("PASS");
+    }
+    expect: {
+        (function(await) {
+            (async () => console.log(arguments[0]))();
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}

test/compress/collapse_vars.js

@@ -3145,8 +3145,8 @@ issue_2313_2: {
         var c = 0;
         !function a() {
             a && c++;
-            var a = 0;
-            a && c++;
+            var a;
+            (a = 0) && c++;
         }();
         console.log(c);
     }
@@ -4273,8 +4273,8 @@ issue_2436_14: {
         var b = {};
         (function() {
             a && function(c, d) {
-                console.log(c, d);
-            }(b, a);
+                console.log(b, d);
+            }(0, a);
         })();
     }
     expect_stdout: true
@@ -5502,8 +5502,7 @@ collapse_rhs_lhs_2: {
     expect: {
         var b = 1;
         (function f(f) {
-            f = b;
-            f[b] = 0;
+            b[b] = 0;
         })();
         console.log("PASS");
     }
@@ -5996,7 +5995,7 @@ issue_3215_1: {
         }());
     }
     expect: {
-        console.log(typeof 42);
+        console.log("number");
     }
     expect_stdout: "number"
 }
@@ -8662,3 +8661,47 @@ issue_4430_2: {
     }
     expect_stdout: "PASS"
 }
+
+collapse_and_assign: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var log = console.log;
+        var a = {
+            p: "PASS",
+        };
+        console && (a = a.p);
+        log(a);
+    }
+    expect: {
+        var log = console.log;
+        var a = {
+            p: "PASS",
+        };
+        log(a = console ? a.p : a);
+    }
+    expect_stdout: "PASS"
+}
+
+collapse_or_assign: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var log = console.log;
+        var a = {
+            p: "PASS",
+        };
+        a.q || (a = a.p);
+        log(a);
+    }
+    expect: {
+        var log = console.log;
+        var a = {
+            p: "PASS",
+        };
+        log(a = !a.q ? a.p : a);
+    }
+    expect_stdout: "PASS"
+}

test/compress/const.js

@@ -658,6 +658,30 @@ legacy_scope: {
     expect_stdout: true
 }
 
+hoist_vars: {
+    options = {
+        hoist_vars: true,
+    }
+    input: {
+        {
+            const a = "FAIL";
+            var b = 42;
+        }
+        var a = "PASS";
+        console.log(a, b);
+    }
+    expect: {
+        var b;
+        {
+            const a = "FAIL";
+            b = 42;
+        }
+        var a = "PASS";
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
 issue_4191: {
     options = {
         functions: true,
@@ -1375,3 +1399,38 @@ issue_4365_2: {
     }
     expect_stdout: true
 }
+
+issue_4527: {
+    mangle = {}
+    input: {
+        (function() {
+            try {
+                throw 1;
+            } catch (a) {
+                try {
+                    const a = FAIL;
+                } finally {
+                    if (!b)
+                        return console.log("aaaa");
+                }
+            }
+            var b;
+        })();
+    }
+    expect: {
+        (function() {
+            try {
+                throw 1;
+            } catch (a) {
+                try {
+                    const a = FAIL;
+                } finally {
+                    if (!t)
+                        return console.log("aaaa");
+                }
+            }
+            var t;
+        })();
+    }
+    expect_stdout: "aaaa"
+}

test/compress/dead-code.js

@@ -725,7 +725,7 @@ issue_2749: {
     expect: {
         var a = 2, c = "PASS";
         while (a--)
-            b = void 0, b ? c = "FAIL" : b = 1;
+            b = void 0, b ? c = "FAIL" : 1;
         var b;
         console.log(c);
     }
@@ -1399,3 +1399,21 @@ issue_4366: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4570: {
+    options = {
+        dead_code: true,
+        inline: true,
+    }
+    input: {
+        var a = function(b) {
+            return a += b;
+        }() ? 0 : a;
+        console.log(a);
+    }
+    expect: {
+        var a = (a += void 0) ? 0 : a;
+        console.log(a);
+    }
+    expect_stdout: "NaN"
+}

test/compress/destructured.js

@@ -40,7 +40,7 @@ redefine_arguments_2: {
 
 redefine_arguments_3: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -188,7 +188,7 @@ funarg_side_effects_1: {
     }
     expect: {
         try {
-            (function({}) {})();
+            [ {} ] = [];
         } catch (e) {
             console.log("PASS");
         }
@@ -259,7 +259,7 @@ funarg_side_effects_3: {
 
 funarg_unused_1: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -318,7 +318,7 @@ funarg_unused_3: {
 
 funarg_unused_4: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         pure_getters: "strict",
         unused: true,
     }
@@ -384,7 +384,7 @@ funarg_unused_6_inline: {
 
 funarg_unused_6_keep_fargs: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -426,7 +426,7 @@ funarg_collapse_vars_1: {
 funarg_collapse_vars_2: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -505,7 +505,7 @@ funarg_reduce_vars_1: {
 funarg_reduce_vars_2: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         pure_getters: "strict",
         reduce_vars: true,
         unsafe: true,
@@ -682,7 +682,7 @@ funarg_inline: {
     }
     expect: {
         try {
-            (function({}) {})();
+            [ {} ] = [];
         } catch (e) {
             console.log("PASS");
         }
@@ -691,6 +691,28 @@ funarg_inline: {
     node_version: ">=6"
 }
 
+process_boolean_returns: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        console.log(function({ length }) {
+            return length ? "FAIL" : "PASS";
+        }(function() {
+            return 42;
+        }));
+    }
+    expect: {
+        console.log(function({ length }) {
+            return length ? "FAIL" : "PASS";
+        }(function() {
+            return 42;
+        }));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 simple_const: {
     options = {
         evaluate: true,
@@ -1101,7 +1123,7 @@ join_vars: {
 
 keep_fargs: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -1336,6 +1358,24 @@ fn_name_unused: {
     node_version: ">=6"
 }
 
+hoist_vars: {
+    options = {
+        hoist_vars: true,
+    }
+    input: {
+        var a = "PASS";
+        var [ b ] = [ 42 ];
+        console.log(a, b);
+    }
+    expect: {
+        var a = "PASS";
+        var [ b ] = [ 42 ];
+        console.log(a, b);
+    }
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
 issue_4280: {
     options = {
         evaluate: true,
@@ -1678,10 +1718,14 @@ issue_4312: {
     expect: {
         var a;
         b = "PASS",
-        (function({
-            [a = b]: d,
-        }){})((c = "FAIL") && c);
-        var b, c;
+        c = "FAIL",
+        [
+            {
+                [a = b]: d,
+            },
+        ] = [ c && c ],
+        void 0;
+        var b, c, d;
         console.log(a);
     }
     expect_stdout: "PASS"
@@ -1743,9 +1787,7 @@ issue_4319: {
         function f(a) {
             while (!a);
         }
-        console.log(function({}) {
-            return f(console);
-        }(0));
+        console.log(([ {} ] = [ 0 ], f(console)));
     }
     expect_stdout: "undefined"
     node_version: ">=6"
@@ -1754,7 +1796,7 @@ issue_4319: {
 issue_4321: {
     options = {
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         try {
@@ -1769,11 +1811,9 @@ issue_4321: {
     }
     expect: {
         try {
-            console.log(function({}) {
-                return function() {
-                    while (!console);
-                }();
-            }());
+            console.log(([ {} ] = [], function() {
+                while (!console);
+            }()));
         } catch (e) {
             console.log("PASS");
         }
@@ -1804,11 +1844,15 @@ issue_4323: {
     }
     expect: {
         var a = 0;
-        (function({
-            [function a() {
-                console.log(typeof a);
-            }()]: d,
-        }) {})(0);
+        [
+            {
+                [function a() {
+                    console.log(typeof a);
+                }()]: d,
+            },
+        ] = [ 0 ],
+        void 0;
+        var d;
         e = 1,
         console.log,
         void e.p;
@@ -2037,3 +2081,409 @@ issue_4425: {
     expect_stdout: "PASS"
     node_version: ">=8"
 }
+
+issue_4436_Infinity: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(function({
+            [delete Infinity]: a,
+        }) {
+            var Infinity;
+            return a;
+        }({
+            true: "FAIL",
+            false: "PASS",
+        }));
+    }
+    expect: {
+        console.log(function({
+            [delete Infinity]: a,
+        }) {
+            return a;
+        }({
+            true: "FAIL",
+            false: "PASS",
+        }));
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+issue_4436_NaN: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(function({
+            [delete NaN]: a,
+        }) {
+            var NaN;
+            return a;
+        }({
+            true: "FAIL",
+            false: "PASS",
+        }));
+    }
+    expect: {
+        console.log(function({
+            [delete NaN]: a,
+        }) {
+            return a;
+        }({
+            true: "FAIL",
+            false: "PASS",
+        }));
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+issue_4436_undefined: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(function({
+            [delete undefined]: a,
+        }) {
+            var undefined;
+            return a;
+        }({
+            true: "FAIL",
+            false: "PASS",
+        }));
+    }
+    expect: {
+        console.log(function({
+            [delete undefined]: a,
+        }) {
+            return a;
+        }({
+            true: "FAIL",
+            false: "PASS",
+        }));
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+issue_4446: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        a = "PASS";
+        var a = [ a[0] ] = [ a ];
+        console.log(a[0]);
+    }
+    expect: {
+        a = "PASS";
+        var a = [ a[0] ] = [ a ];
+        console.log(a[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4456: {
+    options = {
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        var o = {
+            set p(v) {
+                console.log(v);
+            },
+        };
+        [ function() {
+            try {
+                return o;
+            } catch ({}) {}
+        }().p ] = [ "PASS" ];
+    }
+    expect: {
+        var o = {
+            set p(v) {
+                console.log(v);
+            },
+        };
+        [ function() {
+            try {
+                return o;
+            } catch ({}) {}
+        }().p ] = [ "PASS" ];
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4485_1: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        (function([]) {
+            var arguments;
+            try {
+                arguments.length;
+            } catch (e) {
+                console.log("PASS");
+            }
+        })([]);
+    }
+    expect: {
+        (function([]) {
+            var arguments;
+            try {
+                arguments.length;
+            } catch (e) {
+                console.log("PASS");
+            }
+        })([]);
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+issue_4485_2: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        (function([]) {
+            var arguments = null;
+            try {
+                arguments.length;
+            } catch (e) {
+                console.log("PASS");
+            }
+        })([]);
+    }
+    expect: {
+        (function([]) {
+            var arguments = null;
+            try {
+                arguments.length;
+            } catch (e) {
+                console.log("PASS");
+            }
+        })([]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4485_3: {
+    options = {
+        keep_fargs: false,
+        unused: true,
+    }
+    input: {
+        (function([]) {
+            var arguments;
+            try {
+                arguments.length;
+            } catch (e) {
+                console.log("PASS");
+            }
+        })([]);
+    }
+    expect: {
+        (function([]) {
+            var arguments;
+            try {
+                arguments.length;
+            } catch (e) {
+                console.log("PASS");
+            }
+        })([]);
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+issue_4500: {
+    options = {
+        evaluate: true,
+        keep_fnames: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f(b) {
+            return [ b ] = [], b;
+        }("FAIL");
+        console.log(a || "PASS");
+    }
+    expect: {
+        var a = function f(b) {
+            return [ b ] = [], b;
+        }("FAIL");
+        console.log(a || "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4504: {
+    options = {
+        inline: true,
+        merge_vars: true,
+    }
+    input: {
+        A = "FAIL";
+        (function f(a) {
+            ({
+                [console.log(a)]: 0[(b => console + b)(A)]
+            } = 0);
+        })("PASS");
+    }
+    expect: {
+        A = "FAIL";
+        (function f(a) {
+            ({
+                [console.log(a)]: 0[b = A, console + b]
+            } = 0);
+            var b;
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4508: {
+    options = {
+        inline: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        for (var i = 0; i < 2; i++)
+            (function f([ a ]) {
+                var a = console.log(a) && b, b = null;
+            })([ "PASS" ]);
+    }
+    expect: {
+        for (var i = 0; i < 2; i++)
+            [ [ a ] ] = [ [ "PASS" ] ],
+            b = void 0,
+            a = console.log(a) && b,
+            b = null,
+            void 0;
+        var a, b;
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+    ]
+    node_version: ">=6"
+}
+
+issue_4512: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        console.log(function([ a, b = a ]) {}([]));
+    }
+    expect: {
+        console.log(function([ a, b = a ]) {}([]));
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+issue_4519_1: {
+    options = {
+        arguments: true,
+        keep_fargs: false,
+    }
+    input: {
+        try {
+            (function() {
+                var [ arguments ] = [];
+                arguments[0];
+            })();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            (function() {
+                var [ arguments ] = [];
+                arguments[0];
+            })();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4519_2: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        try {
+            (function() {
+                var [ arguments ] = [];
+                arguments[0];
+            })();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            (function() {
+                var [ arguments ] = [];
+                arguments[0];
+            })();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4554: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        A = "PASS";
+        var a = "FAIL";
+        try {
+            (function({}, b) {
+                return b;
+            })(void 0, a = A);
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect: {
+        A = "PASS";
+        var a = "FAIL";
+        try {
+            (function({}, b) {
+                return b;
+            })(void 0, a = A);
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/compress/drop-unused.js

@@ -4,15 +4,16 @@ unused_funarg_1: {
         unused: true,
     }
     input: {
-        function f(a, b, c, d, e) {
+        console.log(function f(a, b, c, d, e) {
             return a + b;
-        }
+        }(14, 28));
     }
     expect: {
-        function f(a, b) {
+        console.log(function(a, b) {
             return a + b;
-        }
+        }(14, 28));
     }
+    expect_stdout: "42"
 }
 
 unused_funarg_2: {
@@ -21,15 +22,16 @@ unused_funarg_2: {
         unused: true,
     }
     input: {
-        function f(a, b, c, d, e) {
+        console.log(function f(a, b, c, d, e) {
             return a + c;
-        }
+        }(14, 21, 28));
     }
     expect: {
-        function f(a, b, c) {
+        console.log(function(a, c) {
             return a + c;
-        }
+        }(14, 28));
     }
+    expect_stdout: "42"
 }
 
 unused_nested_function: {
@@ -357,37 +359,6 @@ drop_toplevel_vars: {
     }
 }
 
-drop_toplevel_vars_fargs: {
-    options = {
-        keep_fargs: false,
-        toplevel: "vars",
-        unused: true,
-    }
-    input: {
-        var a, b = 1, c = g;
-        function f(d) {
-            return function() {
-                c = 2;
-            };
-        }
-        a = 2;
-        function g() {}
-        function h() {}
-        console.log(b = 3);
-    }
-    expect: {
-        function f() {
-            return function() {
-                2;
-            };
-        }
-        2;
-        function g() {}
-        function h() {}
-        console.log(3);
-    }
-}
-
 drop_toplevel_all: {
     options = {
         toplevel: true,
@@ -625,13 +596,14 @@ drop_fargs: {
         unused: true,
     }
     input: {
-        function f(a) {
+        console.log(function f(a) {
             var b = a;
-        }
+        }());
     }
     expect: {
-        function f() {}
+        console.log(function() {}());
     }
+    expect_stdout: "undefined"
 }
 
 drop_fnames: {
@@ -2027,7 +1999,7 @@ issue_3192_1: {
 
 issue_3192_2: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -2435,7 +2407,7 @@ issue_3673: {
 
 issue_3746: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         side_effects: true,
         unused: true,
     }
@@ -2697,8 +2669,7 @@ issue_3956: {
         })();
     }
     expect: {
-        var c, d;
-        c += 0,
+        var d;
         console.log(NaN),
         d = 1 ^ console.log(1),
         console.log(d);
@@ -2713,7 +2684,7 @@ issue_3956: {
 issue_3962_1: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         toplevel: true,
         unused: true,
@@ -2731,13 +2702,13 @@ issue_3962_1: {
     }
     expect: {
         var a = 0;
-        a = (function(c) {
+        (function(c) {
             do {
                 console;
                 0..toString();
             } while (0);
             if (c) console.log("PASS");
-        }(1), 0);
+        })(1);
         void 0;
     }
     expect_stdout: "PASS"
@@ -2745,7 +2716,7 @@ issue_3962_1: {
 
 issue_3962_2: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         side_effects: true,
         toplevel: true,
@@ -2764,13 +2735,13 @@ issue_3962_2: {
     }
     expect: {
         var a = 0;
-        a = (function(c) {
+        (function(c) {
             do {
                 console;
                 0..toString();
             } while (0);
             if (c) console.log("PASS");
-        }(1), 0);
+        })(1);
     }
     expect_stdout: "PASS"
 }
@@ -2827,7 +2798,9 @@ issue_4017: {
         var a = 0;
         console.log(function() {
             c &= 0;
-            var c = (a++, A = a, 0);
+            var c;
+            a++,
+            A = a;
         }());
     }
     expect_stdout: "undefined"
@@ -2948,7 +2921,7 @@ issue_4133: {
 
 issue_4144: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -3153,3 +3126,125 @@ issue_4413: {
     }
     expect_stdout: "0"
 }
+
+issue_4464_1: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            var a = function() {};
+            return [ arguments, a ];
+        }
+        console.log(typeof f()[1]);
+    }
+    expect: {
+        function f(a) {
+            a = function() {};
+            return [ arguments, a ];
+        }
+        console.log(typeof f()[1]);
+    }
+    expect_stdout: "function"
+}
+
+issue_4464_2: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            var a = function() {};
+            return [ arguments, a ];
+        }
+        console.log(typeof f(42)[0][0]);
+    }
+    expect: {
+        function f(a) {
+            a = function() {};
+            return [ arguments, a ];
+        }
+        console.log(typeof f(42)[0][0]);
+    }
+    expect_stdout: "function"
+}
+
+issue_4464_3: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function a(a) {
+            var a = function() {};
+            return [ arguments[0], a ];
+        })(42).forEach(function(b) {
+            console.log(typeof b);
+        });
+    }
+    expect: {
+        (function(a) {
+            a = function() {};
+            return [ arguments[0], a ];
+        })(42).forEach(function(b) {
+            console.log(typeof b);
+        });
+    }
+    expect_stdout: [
+        "function",
+        "function",
+    ]
+}
+
+issue_4558_1: {
+    options = {
+        evaluate: true,
+        pure_getters: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 0;
+        var b = 1, b = c >>>= a;
+        var c = 0;
+        b && 0[a++],
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        var b = c >>>= a;
+        var c;
+        b && a++,
+        console.log(a);
+    }
+    expect_stdout: "0"
+}
+
+issue_4558_2: {
+    options = {
+        evaluate: true,
+        ie8: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var a = 1;
+            var b = (a = NaN) || (console.log("PASS"), 2);
+            return a;
+        })();
+    }
+    expect: {
+        (function() {
+            var a;
+            (a = NaN) || console.log("PASS");
+            return a;
+        })();
+    }
+    expect_stdout: "PASS"
+}

test/compress/evaluate.js

@@ -3117,3 +3117,61 @@ issue_4422: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4480: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var a = function f(b) {
+            b = "FAIL";
+            arguments[0] = "PASS";
+            var arguments = 0;
+            console.log(b);
+        }(a);
+    }
+    expect: {
+        var a = function(b) {
+            b = "FAIL";
+            arguments[0] = "PASS";
+            var arguments = 0;
+            console.log(b);
+        }(a);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4552: {
+    options = {
+        evaluate: true,
+        keep_fnames: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f(b) {
+            return function() {
+                b++;
+                try {
+                    return b;
+                } catch (e) {}
+            }();
+        }();
+        console.log(a);
+    }
+    expect: {
+        var a = function f(b) {
+            return function() {
+                b++;
+                try {
+                    return b;
+                } catch (e) {}
+            }();
+        }();
+        console.log(a);
+    }
+    expect_stdout: "NaN"
+}

test/compress/functions.js

@@ -229,7 +229,7 @@ issue_203: {
     }
     expect: {
         var m = {};
-        var fn = Function("n,o", "o.exports=42");
+        var fn = Function("n,o,t", "o.exports=42");
         fn(null, m, m.exports);
         console.log(m.exports);
     }
@@ -2175,7 +2175,7 @@ issue_3016_3: {
     expect: {
         var b = 1;
         do {
-            console.log((a = void 0, a ? "FAIL" : a = "PASS"));
+            console.log((a = void 0, a ? "FAIL" : "PASS"));
         } while (b--);
         var a;
     }
@@ -2208,7 +2208,7 @@ issue_3016_3_ie8: {
     expect: {
         var b = 1;
         do {
-            console.log((a = void 0, a ? "FAIL" : a = "PASS"));
+            console.log((a = void 0, a ? "FAIL" : "PASS"));
         } while (b--);
         var a;
     }
@@ -4230,7 +4230,7 @@ substitute: {
 substitute_add_farg: {
     options = {
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
     }
     input: {
         function f(g) {
@@ -4411,7 +4411,9 @@ substitute_drop_farg: {
                 return f;
             },
             function() {
-                return f;
+                return function(d, e) {
+                    return f(d, e);
+                };
             },
         ].forEach(function(g) {
             console.log(g()(o), g().call(o, o));
@@ -4594,7 +4596,7 @@ substitute_use_strict: {
 issue_3833: {
     options = {
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         toplevel: true,
         unused: true,
@@ -4751,7 +4753,7 @@ issue_4006: {
         dead_code: true,
         evaluate: true,
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         sequences: true,
         side_effects: true,
@@ -5132,8 +5134,8 @@ issue_4259: {
         console.log(typeof a);
     }
     expect: {
-        function a() {
-            for (a in a);
+        var a = function b() {
+            for (b in b);
         }
         a();
         console.log(typeof a);
@@ -5223,3 +5225,61 @@ trailing_comma: {
     expect_exact: 'new function(a,b){console.log(b,a)}(42,"PASS");'
     expect_stdout: "PASS 42"
 }
+
+issue_4451: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f() {
+            for (f in "foo")
+                return f;
+        };
+        while (console.log(typeof a()));
+    }
+    expect: {
+        var a = function f() {
+            for (f in "foo")
+                return f;
+        };
+        while (console.log(typeof a()));
+    }
+    expect_stdout: "function"
+}
+
+issue_4471: {
+    options = {
+        inline: true,
+        reduce_funcs: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        f(f());
+        function f() {
+            return g();
+        }
+        function g() {
+            {
+                console.log("PASS");
+            }
+        }
+    }
+    expect: {
+        f(g());
+        function f() {
+            return g();
+        }
+        function g() {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+    ]
+}

test/compress/hoist_vars.js

@@ -89,6 +89,31 @@ sequences_funs: {
     }
 }
 
+catch_var: {
+    options = {
+        dead_code: true,
+        hoist_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        try {
+            a;
+        } catch (a) {
+            var a = 0;
+            a;
+        }
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}
+
 issue_2295: {
     options = {
         collapse_vars: true,
@@ -109,3 +134,76 @@ issue_2295: {
         }
     }
 }
+
+issue_4487: {
+    options = {
+        functions: true,
+        hoist_vars: true,
+        keep_fnames: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f() {
+            var f = console.log(typeof f);
+        };
+        var b = a();
+    }
+    expect: {
+        function a() {
+            var a = console.log(typeof a);
+        }
+        a();
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4489: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        A = 0;
+        var o = !0 || null;
+        for (var k in o);
+        console.log(k);
+    }
+    expect: {
+        !(A = 0);
+        for (var k in true);
+        console.log(k);
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4517: {
+    options = {
+        collapse_vars: true,
+        hoist_vars: true,
+        join_vars: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            var a = 2;
+            A = a;
+            var b = typeof !1;
+            return A + b;
+        }());
+    }
+    expect: {
+        console.log(function() {
+            var a = 2;
+            A = a;
+            return A + typeof !1;
+        }());
+    }
+    expect_stdout: "2boolean"
+}

test/compress/ie8.js

@@ -2900,3 +2900,22 @@ issue_4250: {
     }
     expect_stdout: "0"
 }
+
+issue_4568: {
+    options = {
+        ie8: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(typeof f, function(a) {
+            return a.length;
+        }([ function f() {} ]));
+    }
+    expect: {
+        console.log(typeof f, function(a) {
+            return a.length;
+        }([ function f() {} ]));
+    }
+    expect_stdout: "undefined 1"
+}

test/compress/issue-976.js

@@ -63,42 +63,81 @@ eval_unused: {
         unused: true,
     }
     input: {
-        function f1(a, eval, c, d, e) {
-            return a('c') + eval;
-        }
-        function f2(a, b, c, d, e) {
-            return a + eval('c');
-        }
-        function f3(a, eval, c, d, e) {
-            return a + eval('c');
+        function o(k) {
+            return { c: 14 }[k];
         }
+        console.log(function f1(a, eval, c, d, e) {
+            return a("c") + eval;
+        }(o, 28, true));
+        console.log(function f2(a, b, c, d, e) {
+            return a + eval("c");
+        }(14, true, 28));
+        console.log(function f3(a, eval, c, d, e) {
+            return a + eval("c");
+        }(28, o, true));
     }
     expect: {
-        function f1(a, eval) {
-            return a('c') + eval;
-        }
-        function f2(a, b, c, d, e) {
-            return a + eval('c');
-        }
-        function f3(a, eval, c, d, e) {
-            return a + eval('c');
+        function o(k) {
+            return { c: 14 }[k];
         }
+        console.log(function(a, eval) {
+            return a("c") + eval;
+        }(o, 28));
+        console.log(function f2(a, b, c, d, e) {
+            return a + eval("c");
+        }(14, true, 28));
+        console.log(function f3(a, eval, c, d, e) {
+            return a + eval("c");
+        }(28, o, true));
     }
+    expect_stdout: [
+        "42",
+        "42",
+        "42",
+    ]
 }
 
 eval_mangle: {
-    mangle = {
-    };
-    input: {
-        function f1(a, eval, c, d, e) {
-            return a('c') + eval;
-        }
-        function f2(a, b, c, d, e) {
-            return a + eval('c');
-        }
-        function f3(a, eval, c, d, e) {
-            return a + eval('c');
-        }
+    mangle = {}
+    beautify = {
+        beautify: true,
     }
-    expect_exact: 'function f1(n,c,e,a,f){return n("c")+c}function f2(a,b,c,d,e){return a+eval("c")}function f3(a,eval,c,d,e){return a+eval("c")}'
+    input: {
+        function o(k) {
+            return { cc: 14 }[k + "c"];
+        }
+        console.log(function f1(a, eval, c, d, e) {
+            return a("c") + eval;
+        }(o, 28, true));
+        console.log(function f2(a, b, c, d, e) {
+            return a + eval("c");
+        }(14, true, 28));
+        console.log(function f3(a, eval, c, d, e) {
+            return a + eval("c");
+        }(28, o, true));
+    }
+    expect_exact: [
+        "function o(o) {",
+        "    return {",
+        "        cc: 14",
+        '    }[o + "c"];',
+        "}",
+        "",
+        "console.log(function o(c, e, n, r, t) {",
+        '    return c("c") + e;',
+        "}(o, 28, true));",
+        "",
+        "console.log(function f2(a, b, c, d, e) {",
+        '    return a + eval("c");',
+        "}(14, true, 28));",
+        "",
+        "console.log(function f3(a, eval, c, d, e) {",
+        '    return a + eval("c");',
+        "}(28, o, true));",
+    ]
+    expect_stdout: [
+        "42",
+        "42",
+        "42",
+    ]
 }

test/compress/join_vars.js

@@ -790,7 +790,7 @@ issue_3795: {
         dead_code: true,
         evaluate: true,
         join_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         loops: true,
         passes: 2,
         reduce_vars: true,

test/compress/keep_fargs.js

@@ -18,43 +18,6 @@ keep_fargs_false: {
         function j(e) {}
         console.log(h(), i().length, j.length);
     }
-    expect: {
-        console.log(function f() {
-            return f.length;
-        }(), function g() {
-            return g;
-        }().length);
-        function h() {
-            return h.length;
-        }
-        function i() {
-            return i;
-        }
-        function j() {}
-        console.log(h(), i().length, j.length);
-    }
-}
-
-keep_fargs_strict: {
-    options = {
-        keep_fargs: "strict",
-        unused: true,
-    }
-    input: {
-        console.log(function f(a) {
-            return f.length;
-        }(), function g(b) {
-            return g;
-        }().length);
-        function h(c) {
-            return h.length;
-        }
-        function i(d) {
-            return i;
-        }
-        function j(e) {}
-        console.log(h(), i().length, j.length);
-    }
     expect: {
         console.log(function f(a) {
             return f.length;
@@ -117,61 +80,11 @@ keep_fargs_true: {
     ]
 }
 
-replace_index: {
-    options = {
-        arguments: true,
-        evaluate: true,
-        keep_fargs: "strict",
-        properties: true,
-    }
-    input: {
-        var arguments = [];
-        console.log(arguments[0]);
-        (function() {
-            console.log(arguments[1], arguments["1"], arguments["foo"]);
-        })("bar", 42);
-        (function(a, b) {
-            console.log(arguments[1], arguments["1"], arguments["foo"]);
-        })("bar", 42);
-        (function(arguments) {
-            console.log(arguments[1], arguments["1"], arguments["foo"]);
-        })("bar", 42);
-        (function() {
-            var arguments;
-            console.log(arguments[1], arguments["1"], arguments["foo"]);
-        })("bar", 42);
-    }
-    expect: {
-        var arguments = [];
-        console.log(arguments[0]);
-        (function(argument_0, argument_1) {
-            console.log(argument_1, argument_1, arguments.foo);
-        })("bar", 42);
-        (function(a, b) {
-            console.log(b, b, arguments.foo);
-        })("bar", 42);
-        (function(arguments) {
-            console.log(arguments[1], arguments[1], arguments.foo);
-        })("bar", 42);
-        (function() {
-            var arguments;
-            console.log(arguments[1], arguments[1], arguments.foo);
-        })("bar", 42);
-    }
-    expect_stdout: [
-        "undefined",
-        "42 42 undefined",
-        "42 42 undefined",
-        "a a undefined",
-        "42 42 undefined",
-    ]
-}
-
 replace_index_strict: {
     options = {
         arguments: true,
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         properties: true,
         reduce_vars: true,
     }
@@ -202,7 +115,7 @@ replace_index_strict: {
 issue_1858: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         pure_getters: true,
         unused: true,
     }
@@ -224,7 +137,7 @@ issue_1858: {
 issue_2187_2: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -245,7 +158,7 @@ issue_2187_2: {
 issue_2203_2: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -280,7 +193,7 @@ issue_2203_2: {
 issue_2298: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
@@ -323,7 +236,7 @@ issue_2298: {
 issue_2319_1: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -346,7 +259,7 @@ issue_2319_1: {
 issue_2319_2: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -371,7 +284,7 @@ issue_2319_2: {
 issue_2319_3: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -396,7 +309,7 @@ issue_2319_3: {
 issue_2425_1: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -419,7 +332,7 @@ issue_2425_1: {
 issue_2425_2: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -442,7 +355,7 @@ issue_2425_2: {
 issue_2425_3: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -465,7 +378,7 @@ issue_2425_3: {
 issue_2436_13: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         passes: 2,
         reduce_vars: true,
         unused: true,
@@ -499,7 +412,7 @@ issue_2436_13: {
 issue_2506: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         passes: 2,
         reduce_vars: true,
         unused: true,
@@ -538,7 +451,7 @@ issue_2506: {
 
 issue_2226_1: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         side_effects: true,
         unused: true,
     }
@@ -585,7 +498,7 @@ issue_2226_1: {
 issue_2226_2: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         sequences: true,
         side_effects: true,
         unused: true,
@@ -607,7 +520,7 @@ issue_2226_2: {
 issue_2226_3: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         side_effects: true,
         unused: true,
     }
@@ -627,7 +540,7 @@ issue_2226_3: {
 
 issue_3192: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -657,7 +570,7 @@ issue_3192: {
 if_increment: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -679,7 +592,7 @@ if_increment: {
 try_increment: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -703,7 +616,7 @@ try_increment: {
 issue_2630_3: {
     options = {
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -740,7 +653,7 @@ issue_2630_3: {
 issue_3364: {
     options = {
         functions: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         toplevel: true,
         unused: true,
@@ -805,7 +718,7 @@ issue_3364: {
 
 defun_label: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
@@ -837,7 +750,7 @@ defun_label: {
 
 iife_func_side_effects: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_funcs: true,
         reduce_vars: true,
         unused: true,
@@ -889,7 +802,7 @@ iife_func_side_effects: {
 issue_1595_1: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_funcs: true,
         reduce_vars: true,
         unused: true,
@@ -909,7 +822,7 @@ issue_1595_1: {
 issue_1595_2: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_funcs: true,
         reduce_vars: true,
         unused: true,
@@ -929,7 +842,7 @@ issue_1595_2: {
 issue_1595_3: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
@@ -950,7 +863,7 @@ issue_1595_3: {
 issue_1595_4: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_funcs: true,
         reduce_vars: true,
         unused: true,
@@ -972,7 +885,7 @@ issue_1595_4: {
 
 duplicate_lambda_defun_name_1: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
     }
     input: {
@@ -992,7 +905,7 @@ duplicate_lambda_defun_name_1: {
 
 duplicate_lambda_defun_name_2: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         passes: 2,
         reduce_vars: true,
         unused: true,
@@ -1013,7 +926,7 @@ duplicate_lambda_defun_name_2: {
 
 function_name_mangle: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         keep_fnames: true,
         reduce_vars: true,
         unused: true,
@@ -1031,7 +944,7 @@ function_name_mangle: {
 
 function_name_mangle_ie8: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         keep_fnames: true,
         reduce_vars: true,
         unused: true,
@@ -1052,7 +965,7 @@ function_name_mangle_ie8: {
 
 issue_3420_1: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -1075,7 +988,7 @@ issue_3420_1: {
 issue_3420_2: {
     options = {
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -1096,7 +1009,7 @@ issue_3420_2: {
 issue_3420_3: {
     options = {
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -1118,7 +1031,7 @@ issue_3420_3: {
 
 issue_3423_1: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -1138,7 +1051,7 @@ issue_3423_1: {
 
 issue_3423_2: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -1165,7 +1078,7 @@ collapse_vars_repeated: {
         hoist_funs: true,
         if_return: true,
         join_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         loops: true,
         properties: true,
         reduce_funcs: true,
@@ -1212,7 +1125,7 @@ collapse_vars_repeated: {
 chained_3: {
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -1236,7 +1149,7 @@ replace_all_var_scope: {
     rename = true
     options = {
         collapse_vars: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     mangle = {}
@@ -1265,7 +1178,7 @@ replace_all_var_scope: {
 
 issue_1583: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
@@ -1302,7 +1215,7 @@ issues_3267_1: {
         dead_code: true,
         evaluate: true,
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         sequences: true,
         side_effects: true,
@@ -1331,7 +1244,7 @@ issues_3267_1: {
 
 trailing_argument_side_effects: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -1355,7 +1268,7 @@ trailing_argument_side_effects: {
 
 recursive_iife_1: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -1374,7 +1287,7 @@ recursive_iife_1: {
 
 recursive_iife_2: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -1455,7 +1368,7 @@ issue_3619: {
 
 issue_4353_1: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
@@ -1470,7 +1383,7 @@ issue_4353_1: {
 
 issue_4353_2: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }

test/compress/labels.js

@@ -207,3 +207,123 @@ labels_10: {
         }
     }
 }
+
+issue_4466_1: {
+    mangle = {
+        v8: false,
+    }
+    input: {
+        A: if (console.log("PASS"))
+            B:;
+        else
+            C:;
+    }
+    expect: {
+        e: if (console.log("PASS"))
+            l:;
+        else
+            l:;
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_4466_1_v8: {
+    mangle = {
+        v8: true,
+    }
+    input: {
+        A: if (console.log("PASS"))
+            B:;
+        else
+            C:;
+    }
+    expect: {
+        e: if (console.log("PASS"))
+            l:;
+        else
+            o:;
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_4466_2: {
+    mangle = {
+        toplevel: false,
+        v8: false,
+    }
+    input: {
+        if (console.log("PASS"))
+            A:;
+        else
+            B:;
+    }
+    expect: {
+        if (console.log("PASS"))
+            e:;
+        else
+            e:;
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4466_2_v8: {
+    mangle = {
+        toplevel: false,
+        v8: true,
+    }
+    input: {
+        if (console.log("PASS"))
+            A:;
+        else
+            B:;
+    }
+    expect: {
+        if (console.log("PASS"))
+            e:;
+        else
+            l:;
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4466_2_toplevel: {
+    mangle = {
+        toplevel: true,
+        v8: false,
+    }
+    input: {
+        if (console.log("PASS"))
+            A:;
+        else
+            B:;
+    }
+    expect: {
+        if (console.log("PASS"))
+            e:;
+        else
+            e:;
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4466_2_toplevel_v8: {
+    mangle = {
+        toplevel: true,
+        v8: true,
+    }
+    input: {
+        if (console.log("PASS"))
+            A:;
+        else
+            B:;
+    }
+    expect: {
+        if (console.log("PASS"))
+            e:;
+        else
+            e:;
+    }
+    expect_stdout: "PASS"
+}

test/compress/let.js

@@ -359,6 +359,28 @@ reduce_block_2_toplevel: {
     node_version: ">=4"
 }
 
+reduce_vars: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        let a = "PASS";
+        console.log(a);
+        a = "FAIL";
+    }
+    expect: {
+        "use strict";
+        console.log("PASS");
+        "FAIL";
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 hoist_props: {
     options = {
         hoist_props: true,
@@ -1228,3 +1250,92 @@ issue_1753_toplevel: {
     expect_stdout: "0"
     node_version: ">=4"
 }
+
+issue_4438: {
+    options = {
+        if_return: true,
+    }
+    input: {
+        "use strict";
+        function f() {
+            if (console) {
+                {
+                    let a = console.log;
+                    return void a("PASS");
+                }
+            }
+        }
+        f();
+    }
+    expect: {
+        "use strict";
+        function f() {
+            if (!console)
+                ;
+            else {
+                let a = console.log;
+                a("PASS");
+            }
+        }
+        f();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4531_1: {
+    mangle = {
+        ie8: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        var a;
+        console.log(function a() {
+            let a;
+            var b;
+        }());
+    }
+    expect: {
+        "use strict";
+        var o;
+        console.log(function o() {
+            let o;
+            var t;
+        }());
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}
+
+issue_4531_2: {
+    options = {
+        evaluate: true,
+        ie8: true,
+        toplevel: true,
+    }
+    mangle = {
+        ie8: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        var a = console;
+        console.log(typeof a, function a() {
+            let { [console]: a } = 0 && a;
+            var b = console;
+            while (!b);
+        }());
+    }
+    expect: {
+        "use strict";
+        var o = console;
+        console.log(typeof o, function o() {
+            let { [console]: o } = 0;
+            var e = console;
+            while (!e);
+        }());
+    }
+    expect_stdout: "object undefined"
+    node_version: ">=6"
+}

test/compress/loops.js

@@ -1026,7 +1026,7 @@ issue_4075: {
 
 issue_4082: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         loops: true,
         unused: true,
     }
@@ -1050,7 +1050,7 @@ issue_4082: {
 
 issue_4084: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         loops: true,
         passes: 2,
         reduce_vars: true,
@@ -1280,3 +1280,33 @@ issue_4355: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4564: {
+    options = {
+        loops: true,
+        unused: true,
+    }
+    input: {
+        try {
+            throw null;
+        } catch (a) {
+            var a;
+            (function() {
+                for (a in "foo");
+            })();
+            console.log(a);
+        }
+    }
+    expect: {
+        try {
+            throw null;
+        } catch (a) {
+            var a;
+            (function() {
+                for (a in "foo");
+            })();
+            console.log(a);
+        }
+    }
+    expect_stdout: "2"
+}

test/compress/merge_vars.js

@@ -327,7 +327,7 @@ issue_4103: {
 
 issue_4107: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         merge_vars: true,
         reduce_vars: true,
         unused: true,

test/compress/numbers.js

@@ -1386,3 +1386,75 @@ issue_4142: {
     }
     expect_stdout: "0"
 }
+
+issue_4542_1: {
+    options = {
+        evaluate: true,
+        unsafe_math: true,
+    }
+    input: {
+        console.log(function(a) {
+            return a / (1 / (a[0] = 2));
+        }([ 3 ]));
+    }
+    expect: {
+        console.log(function(a) {
+            return a / (1 / (a[0] = 2));
+        }([ 3 ]));
+    }
+    expect_stdout: "4"
+}
+
+issue_4542_2: {
+    options = {
+        evaluate: true,
+        unsafe_math: true,
+    }
+    input: {
+        console.log(function(a) {
+            return a / (1 / --a[0]);
+        }([ 3 ]));
+    }
+    expect: {
+        console.log(function(a) {
+            return a / (1 / --a[0]);
+        }([ 3 ]));
+    }
+    expect_stdout: "4"
+}
+
+issue_4542_3: {
+    options = {
+        evaluate: true,
+        unsafe_math: true,
+    }
+    input: {
+        console.log(function(a) {
+            return a / (0 / (a[0] = 0, 1));
+        }([ 1 ]));
+    }
+    expect: {
+        console.log(function(a) {
+            return a / (0 / (a[0] = 0, 1));
+        }([ 1 ]));
+    }
+    expect_stdout: "NaN"
+}
+
+issue_4542_4: {
+    options = {
+        evaluate: true,
+        unsafe_math: true,
+    }
+    input: {
+        console.log(function(a) {
+            return a / (1 / (a.length = 1));
+        }([ 2, 3 ]));
+    }
+    expect: {
+        console.log(function(a) {
+            return a / (1 / (a.length = 1));
+        }([ 2, 3 ]));
+    }
+    expect_stdout: "2"
+}

test/compress/pure_funcs.js

@@ -685,7 +685,7 @@ issue_3858: {
     options = {
         collapse_vars: true,
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -711,7 +711,7 @@ inline_pure_call_1: {
     options = {
         collapse_vars: true,
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         sequences: true,
         side_effects: true,
@@ -733,7 +733,7 @@ inline_pure_call_2: {
     options = {
         collapse_vars: true,
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         sequences: true,
         side_effects: true,
@@ -756,7 +756,7 @@ inline_pure_call_3: {
         collapse_vars: true,
         evaluate: true,
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         passes: 2,
         reduce_vars: true,
         toplevel: true,

test/compress/pure_getters.js

@@ -1208,3 +1208,32 @@ issue_3427: {
     expect: {}
     expect_stdout: true
 }
+
+issue_4440: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        try {
+            (function() {
+                arguments = null;
+                console.log(arguments.p = "FAIL");
+            })();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            (function() {
+                arguments = null;
+                console.log(arguments.p = "FAIL");
+            })();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+}

test/compress/reduce_vars.js

@@ -2373,7 +2373,7 @@ redefine_farg_1: {
         function f(a) {
             return typeof a;
         }
-        function g() {
+        function g(a) {
             return "number";
         }
         function h(a, b) {
@@ -6928,7 +6928,7 @@ issue_3622: {
     options = {
         evaluate: true,
         inline: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         reduce_vars: true,
         sequences: true,
         toplevel: true,
@@ -7196,7 +7196,7 @@ issue_3894: {
 issue_3922: {
     options = {
         evaluate: true,
-        keep_fargs: "strict",
+        keep_fargs: false,
         pure_getters: "strict",
         reduce_vars: true,
         side_effects: true,
@@ -7601,3 +7601,32 @@ issue_4188_2: {
     }
     expect_stdout: "number undefined"
 }
+
+issue_4568: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        dead_code: true,
+        evaluate: true,
+        loops: true,
+        passes: 2,
+        reduce_vars: true,
+        sequences: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            a && console.log("FAIL");
+            if (1)
+                do {
+                    if (!console.log("PASS")) break;
+                } while (1);
+        })(!(0 !== delete NaN));
+    }
+    expect: {
+        (function(a) {
+            for (a && console.log("FAIL"), 1; console.log("PASS"); ) 1;
+        })(!(0 !== delete NaN));
+    }
+    expect_stdout: "PASS"
+}

test/compress/rests.js

@@ -0,0 +1,665 @@
+arrow_1: {
+    input: {
+        console.log.apply(console, ((...a) => a)("PASS", 42));
+    }
+    expect_exact: 'console.log.apply(console,((...a)=>a)("PASS",42));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+arrow_2: {
+    input: {
+        console.log.apply(console, ((a, ...b) => b)("FAIL", "PASS", 42));
+    }
+    expect_exact: 'console.log.apply(console,((a,...b)=>b)("FAIL","PASS",42));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+arrow_destructured_array_1: {
+    input: {
+        console.log.apply(console, (([ ...a ]) => a)("PASS"));
+    }
+    expect_exact: 'console.log.apply(console,(([...a])=>a)("PASS"));'
+    expect_stdout: "P A S S"
+    node_version: ">=6"
+}
+
+arrow_destructured_array_2: {
+    input: {
+        console.log.apply(console, (([ a, ...b ]) => b)([ "FAIL", "PASS", 42 ]));
+    }
+    expect_exact: 'console.log.apply(console,(([a,...b])=>b)(["FAIL","PASS",42]));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+arrow_destructured_array_3: {
+    input: {
+        console.log((([ [ ...a ] = "FAIL" ]) => a)([ "PASS" ]).join("|"));
+    }
+    expect_exact: 'console.log((([[...a]="FAIL"])=>a)(["PASS"]).join("|"));'
+    expect_stdout: "P|A|S|S"
+    node_version: ">=6"
+}
+
+arrow_destructured_object_1: {
+    input: {
+        var f = ({ ...a }) => a, o = f({ PASS: 42 });
+        for (var k in o)
+            console.log(k, o[k]);
+    }
+    expect_exact: "var f=({...a})=>a,o=f({PASS:42});for(var k in o)console.log(k,o[k]);"
+    expect_stdout: "PASS 42"
+    node_version: ">=8"
+}
+
+arrow_destructured_object_2: {
+    input: {
+        var f = ({ FAIL: a, ...b }) => b, o = f({ PASS: 42, FAIL: null });
+        for (var k in o)
+            console.log(k, o[k]);
+    }
+    expect_exact: "var f=({FAIL:a,...b})=>b,o=f({PASS:42,FAIL:null});for(var k in o)console.log(k,o[k]);"
+    expect_stdout: "PASS 42"
+    node_version: ">=8"
+}
+
+arrow_destructured_object_3: {
+    input: {
+        var f = ([ { ...a } = [ "FAIL" ] ]) => a;
+        var o = f([ "PASS" ]);
+        for (var k in o)
+            console.log(k, o[k]);
+    }
+    expect_exact: 'var f=([{...a}=["FAIL"]])=>a;var o=f(["PASS"]);for(var k in o)console.log(k,o[k]);'
+    expect_stdout: [
+        "0 P",
+        "1 A",
+        "2 S",
+        "3 S",
+    ]
+    node_version: ">=8"
+}
+
+funarg_1: {
+    input: {
+        console.log.apply(console, function(...a) {
+            return a;
+        }("PASS", 42));
+    }
+    expect_exact: 'console.log.apply(console,function(...a){return a}("PASS",42));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+funarg_2: {
+    input: {
+        console.log.apply(console, function(a, ...b) {
+            return b;
+        }("FAIL", "PASS", 42));
+    }
+    expect_exact: 'console.log.apply(console,function(a,...b){return b}("FAIL","PASS",42));'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+destructured_array_1: {
+    input: {
+        var [ ...a ] = [ "PASS", 42 ];
+        console.log.apply(console, a);
+    }
+    expect_exact: 'var[...a]=["PASS",42];console.log.apply(console,a);'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+destructured_array_2: {
+    input: {
+        var [ a, ...b ] = [ "FAIL", "PASS", 42 ];
+        console.log.apply(console, b);
+    }
+    expect_exact: 'var[a,...b]=["FAIL","PASS",42];console.log.apply(console,b);'
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+destructured_object_1: {
+    input: {
+        var { ...a } = [ "FAIL", "PASS", 42 ];
+        console.log(a[1], a[2]);
+    }
+    expect_exact: 'var{...a}=["FAIL","PASS",42];console.log(a[1],a[2]);'
+    expect_stdout: "PASS 42"
+    node_version: ">=8"
+}
+
+destructured_object_2: {
+    input: {
+        var { 0: a, ...b } = [ "FAIL", "PASS", 42 ];
+        console.log(b[1], b[2]);
+    }
+    expect_exact: 'var{0:a,...b}=["FAIL","PASS",42];console.log(b[1],b[2]);'
+    expect_stdout: "PASS 42"
+    node_version: ">=8"
+}
+
+drop_fargs: {
+    options = {
+        keep_fargs: false,
+        rests: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a, ...b) {
+            return b[0];
+        }("FAIL", "PASS"));
+    }
+    expect: {
+        console.log(function(b) {
+            return b[0];
+        }([ "PASS" ]));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+inline: {
+    options = {
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        console.log(function(a, ...[ b, c ]) {
+            return c + b + a;
+        }("SS", "A", "P"));
+    }
+    expect: {
+        console.log(([ a, ...[ b, c ] ] = [ "SS", "A", "P" ], c + b + a));
+        var a, b, c;
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+retain_var: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var [ ...a ] = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect: {
+        var [ ...a ] = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+reduce_destructured_array: {
+    options = {
+        reduce_vars: true,
+        rests: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var [ ...a ] = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect: {
+        console.log([ "PASS" ][0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+reduce_destructured_object: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { ...a } = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect: {
+        var { ...a } = [ "PASS" ];
+        console.log(a[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+retain_destructured_array: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var [ a, ...b ] = [ "FAIL", "PASS", 42 ];
+        console.log.apply(console, b);
+    }
+    expect: {
+        var [ , ...b ] = [ "FAIL", "PASS", 42 ];
+        console.log.apply(console, b);
+    }
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+retain_destructured_object_1: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { 0: a, ...b } = [ "FAIL", "PASS", 42 ];
+        for (var k in b)
+            console.log(k, b[k]);
+    }
+    expect: {
+        var { 0: a, ...b } = [ "FAIL", "PASS", 42 ];
+        for (var k in b)
+            console.log(k, b[k]);
+    }
+    expect_stdout: [
+        "1 PASS",
+        "2 42",
+    ]
+    node_version: ">=8"
+}
+
+retain_destructured_object_2: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { foo: [ a ], ...b } = { foo: [ "FAIL" ], bar: "PASS", baz: 42 };
+        for (var k in b)
+            console.log(k, b[k]);
+    }
+    expect: {
+        var { foo: [], ...b } = { foo: [ "FAIL" ], bar: "PASS", baz: 42 };
+        for (var k in b)
+            console.log(k, b[k]);
+    }
+    expect_stdout: [
+        "bar PASS",
+        "baz 42",
+    ]
+    node_version: ">=8"
+}
+
+retain_funarg_destructured_array_1: {
+    options = {
+        inline: true,
+        keep_fargs: false,
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        console.log((([ ...a ]) => a)([ "PASS" ])[0]);
+    }
+    expect: {
+        console.log((([ ...a ]) => a)([ "PASS" ])[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+retain_funarg_destructured_array_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(function([ a, ...b ]) {
+            return b;
+        }("bar")[1]);
+    }
+    expect: {
+        console.log(function([ , ...b ]) {
+            return b;
+        }("bar")[1]);
+    }
+    expect_stdout: "r"
+    node_version: ">=6"
+}
+
+retain_funarg_destructured_object_1: {
+    options = {
+        inline: true,
+        keep_fargs: false,
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        console.log((({ ...a }) => a)([ "PASS" ])[0]);
+    }
+    expect: {
+        console.log((({ ...a }) => a)([ "PASS" ])[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+retain_funarg_destructured_object_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(function({ p: a, ... b }) {
+            return b;
+        }({ p: "FAIL" }).p || "PASS");
+    }
+    expect: {
+        console.log(function({ p: a, ... b }) {
+            return b;
+        }({ p: "FAIL" }).p || "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+drop_unused_call_args_1: {
+    options = {
+        rests: true,
+        unused: true,
+    }
+    input: {
+        (function(...a) {
+            console.log(a[0]);
+        })(42, console.log("PASS"));
+    }
+    expect: {
+        (function(a) {
+            console.log(a[0]);
+        })([ 42, console.log("PASS") ]);
+    }
+    expect_stdout: [
+        "PASS",
+        "42",
+    ]
+    node_version: ">=6"
+}
+
+drop_unused_call_args_2: {
+    options = {
+        keep_fargs: false,
+        rests: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a, ...b) {
+            return b;
+        }(console).length);
+    }
+    expect: {
+        console.log(function(b) {
+            return b;
+        }((console, [])).length);
+    }
+    expect_stdout: "0"
+    node_version: ">=6"
+}
+
+merge_funarg: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        (function(...a) {
+            var b = a.length;
+            console.log(b);
+        })();
+    }
+    expect: {
+        (function(...b) {
+            var b = b.length;
+            console.log(b);
+        })();
+    }
+    expect_stdout: "0"
+    node_version: ">=6"
+}
+
+merge_funarg_destructured_array: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        (function([ ...a ]) {
+            var b = a.length;
+            console.log(b);
+        })([]);
+    }
+    expect: {
+        (function([ ...b ]) {
+            var b = b.length;
+            console.log(b);
+        })([]);
+    }
+    expect_stdout: "0"
+    node_version: ">=6"
+}
+
+merge_funarg_destructured_object: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        (function({ ...a }) {
+            var b = a[0];
+            console.log(b);
+        })([ "PASS" ]);
+    }
+    expect: {
+        (function({ ...b }) {
+            var b = b[0];
+            console.log(b);
+        })([ "PASS" ]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+keep_arguments: {
+    options = {
+        arguments: true,
+        keep_fargs: false,
+    }
+    input: {
+        (function(...[ {} ]) {
+            console.log(arguments[0]);
+        })("PASS");
+    }
+    expect: {
+        (function(...[ {} ]) {
+            console.log(arguments[0]);
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+drop_rest_array: {
+    options = {
+        rests: true,
+    }
+    input: {
+        var [ ...[ a ]] = [ "PASS" ];
+        console.log(a);
+    }
+    expect: {
+        var [ a ] = [ "PASS" ];
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+drop_rest_arrow: {
+    options = {
+        arrows: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        rests: true,
+    }
+    input: {
+        console.log(((...[ a ]) => a)("PASS"));
+    }
+    expect: {
+        console.log((a => a)("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+drop_rest_lambda: {
+    options = {
+        keep_fargs: false,
+        reduce_vars: true,
+        rests: true,
+        toplevel: true,
+    }
+    input: {
+        function f(...[ a ]) {
+            return a;
+        }
+        console.log(f("PASS"), f(42));
+    }
+    expect: {
+        function f(a) {
+            return a;
+        }
+        console.log(f("PASS"), f(42));
+    }
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+issue_4525_1: {
+    options = {
+        arguments: true,
+    }
+    input: {
+        console.log(function(a, ...[]) {
+            a = "FAIL";
+            return arguments[0];
+        }("PASS"));
+    }
+    expect: {
+        console.log(function(a, ...[]) {
+            a = "FAIL";
+            return arguments[0];
+        }("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4525_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(function(a, ...[]) {
+            a = "FAIL";
+            return arguments[0];
+        }("PASS"));
+    }
+    expect: {
+        console.log(function(a, ...[]) {
+            a = "FAIL";
+            return arguments[0];
+        }("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4538: {
+    options = {
+        rests: true,
+        unused: true,
+    }
+    input: {
+        console.log(typeof function f(...a) {
+            return a.p, f;
+        }()());
+    }
+    expect: {
+        console.log(typeof function f(...a) {
+            return a.p, f;
+        }()());
+    }
+    expect_stdout: "function"
+    node_version: ">=6"
+}
+
+issue_4544_1: {
+    options = {
+        keep_fnames: true,
+        side_effects: true,
+    }
+    input: {
+        try {
+            (function f(...[ {} ]) {})();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            [ ...[ {} ] ] = [];
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4544_2: {
+    options = {
+        keep_fnames: true,
+        side_effects: true,
+    }
+    input: {
+        try {
+            (function f(a, ...[ {} ]) {})([]);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            [ , ...[ {} ] ] = [ [] ];
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_4562: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        rests: true,
+        unsafe: true,
+    }
+    input: {
+        console.log((([ ...[ a ] ]) => a)("foo"));
+    }
+    expect: {
+        console.log((([ a ]) => a)("foo"));
+    }
+    expect_stdout: "f"
+    node_version: ">=6"
+}

test/compress/side_effects.js

@@ -436,7 +436,7 @@ trim_new: {
 
 issue_4325: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         passes: 2,
         pure_getters: "strict",
         reduce_vars: true,

test/compress/spreads.js

@@ -85,6 +85,28 @@ collapse_vars_4: {
     node_version: ">=6"
 }
 
+conditionals_farg: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        function log(msg) {
+            console.log(msg);
+        }
+        var a = 42, b = [ "PASS" ], c = [ "FAIL" ];
+        a ? log(...b) : log(...c);
+    }
+    expect: {
+        function log(msg) {
+            console.log(msg);
+        }
+        var a = 42, b = [ "PASS" ], c = [ "FAIL" ];
+        log(...a ? b : c);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 dont_inline: {
     options = {
         inline: true,
@@ -106,7 +128,7 @@ dont_inline: {
 do_inline: {
     options = {
         inline: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         console.log(function(a) {
@@ -145,7 +167,7 @@ drop_empty_call_1: {
 drop_empty_call_2: {
     options = {
         side_effects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         (function() {})(...[ console.log("PASS") ]);
@@ -159,7 +181,7 @@ drop_empty_call_2: {
 
 convert_hole: {
     options = {
-        spread: true,
+        spreads: true,
     }
     input: {
         console.log(...[ "PASS", , 42 ]);
@@ -192,7 +214,7 @@ keep_property_access: {
 
 keep_fargs: {
     options = {
-        keep_fargs: "strict",
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -253,7 +275,7 @@ reduce_vars_2: {
 convert_setter: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -397,7 +419,7 @@ keep_getter_4: {
 keep_accessor: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -445,7 +467,7 @@ keep_accessor: {
 object_key_order_1: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -475,7 +497,7 @@ object_key_order_1: {
 object_key_order_2: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -505,7 +527,7 @@ object_key_order_2: {
 object_key_order_3: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -535,7 +557,7 @@ object_key_order_3: {
 object_key_order_4: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -565,7 +587,7 @@ object_key_order_4: {
 object_spread_array: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -591,7 +613,7 @@ object_spread_array: {
 object_spread_string: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         var o = {
@@ -648,7 +670,7 @@ unused_var_side_effects: {
 issue_4329: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         console.log({
@@ -727,7 +749,7 @@ issue_4342: {
 issue_4345: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         console.log({
@@ -787,7 +809,7 @@ issue_4361: {
 issue_4363: {
     options = {
         objects: true,
-        spread: true,
+        spreads: true,
     }
     input: {
         ({
@@ -804,3 +826,95 @@ issue_4363: {
     expect_stdout: "PASS"
     node_version: ">=8"
 }
+
+issue_4556: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            var a = "" + [ a++ ];
+            var b = [ ...a ];
+        }());
+    }
+    expect: {
+        console.log(function() {
+            var a;
+        }());
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+issue_4560_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0;
+        (function(...{
+            [a++]: {},
+        }) {})(2);
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        (function(...{
+            [a++]: {},
+        }) {})(2);
+        console.log(a);
+    }
+    expect_stdout: "1"
+    node_version: ">=6"
+}
+
+issue_4560_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 0;
+        (function(...{
+            [a++]: {},
+        }) {})(2);
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        (function(...{
+            [a++]: {},
+        }) {})(2);
+        console.log(a);
+    }
+    expect_stdout: "1"
+    node_version: ">=6"
+}
+
+issue_4560_3: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0, b;
+        [ ...{
+            [a++]: b,
+        } ] = [ "PASS" ];
+        console.log(b);
+    }
+    expect: {
+        var a = 0, b;
+        [ ...{
+            [a++]: b,
+        } ] = [ "PASS" ];
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/input/reduce/destructured_assign.js

@@ -0,0 +1,3 @@
+var o = {};
+[ o[1 + .1 + .1] ] = [ 42 ];
+console.log(o[1.2]);

test/input/reduce/destructured_assign.reduced.js

@@ -0,0 +1,17 @@
+// (beautified)
+var o = {};
+
+[ o[1 + .1 + .1] ] = [];
+
+console.log(o);
+// output: { '1.2000000000000002': undefined }
+// 
+// minify: { '1.2': undefined }
+// 
+// options: {
+//   "compress": {
+//     "unsafe_math": true
+//   },
+//   "mangle": false,
+//   "validate": true
+// }

test/input/reduce/destructured_catch.reduced.js

@@ -1,14 +1,12 @@
 // (beautified)
 try {
     1 in 0;
-} catch ({
-    message: message
-}) {
+} catch (message) {
     console.log(message);
 }
-// output: Cannot use 'in' operator to search for '1' in 0
+// output: TypeError: Cannot use 'in' operator to search for '1' in 0
 // 
-// minify: Cannot use 'in' operator to search for '0' in 0
+// minify: TypeError: Cannot use 'in' operator to search for '0' in 0
 // 
 // options: {
 //   "mangle": false

test/input/reduce/diff_error.js

@@ -1,5 +1,5 @@
-(function f(a) {
-    do {
-        console.log(f.length);
-    } while (console.log(f += 0));
-})();
+console.log(function(undefined) {
+    return undefined[function() {
+        {}
+    }] || 1 + .1 + .1;
+}(42));

test/input/reduce/diff_error.reduced.js

@@ -1,19 +1,14 @@
 // (beautified)
-(function f(a) {
-    do {
-        console.log(f.length);
-    } while (console.log(f += 0));
-})();
-// output: 1
-// function(){}0
+console.log(function() {
+    return 1 + .1 + .1;
+}());
+// output: 1.2000000000000002
 // 
-// minify: 0
-// function(){}0
+// minify: 1.2
 // 
 // options: {
 //   "compress": {
-//     "keep_fargs": false,
-//     "unsafe": true
+//     "unsafe_math": true
 //   },
 //   "mangle": false
 // }

test/input/reduce/setter.js

@@ -1,8 +1,5 @@
-console.log(function f(a) {
-    ({
-        set p(v) {
-            f++;
-        }
-    });
-    return f.length;
-}());
+({
+    set p(v) {
+        console.log(+v + .1 + .1);
+    }
+}).p = 1;

test/input/reduce/setter.reduced.js

@@ -1,20 +1,16 @@
 // (beautified)
-console.log(function f(a) {
-    ({
-        set p(v) {
-            f++;
-        }
-    });
-    return f.length;
-}());
-// output: 1
+({
+    set p(v) {
+        console.log(1 + .1 + .1);
+    }
+}).p = 0;
+// output: 1.2000000000000002
 // 
-// minify: 0
+// minify: 1.2
 // 
 // options: {
 //   "compress": {
-//     "keep_fargs": false,
-//     "unsafe": true
+//     "unsafe_math": true
 //   },
 //   "mangle": false
 // }

test/jetstream.js

@@ -5,7 +5,7 @@
 
 var site = "https://browserbench.org/JetStream1.1";
 if (typeof phantom == "undefined") {
-    require("../tools/exit");
+    require("../tools/tty");
     var args = process.argv.slice(2);
     var debug = args.indexOf("--debug");
     if (debug < 0) {

test/mocha/bug-report.js

@@ -0,0 +1,40 @@
+var assert = require("assert");
+var exec = require("child_process").exec;
+
+describe("UGLIFY_BUG_REPORT", function() {
+    var env = Object.create(process.env);
+    env.UGLIFY_BUG_REPORT = 1;
+    it("Should generate bug report via API", function(done) {
+        exec('"' + process.argv[0] + '"', { env: env }, function(err, stdout) {
+            if (err) throw err;
+            assert.strictEqual(stdout, [
+                "// UGLIFY_BUG_REPORT",
+                "// <<undefined>>",
+                "",
+                "//-------------------------------------------------------------",
+                "// INPUT CODE",
+                "...---...",
+                "",
+            ].join("\n"));
+            done();
+        }).stdin.end('console.log(require("./").minify("...---...").code);');
+    });
+    it("Should generate bug report via CLI", function(done) {
+        exec('"' + process.argv[0] + '" bin/uglifyjs -mc', { env: env }, function(err, stdout) {
+            if (err) throw err;
+            assert.strictEqual(stdout, [
+                "// UGLIFY_BUG_REPORT",
+                "// {",
+                '//   "mangle": {},',
+                '//   "compress": {}',
+                "// }",
+                "",
+                "//-------------------------------------------------------------",
+                "// STDIN",
+                "...---...",
+                "",
+            ].join("\n"));
+            done();
+        }).stdin.end("...---...");
+    });
+});

test/mocha/getter-setter.js

@@ -3,7 +3,7 @@ var UglifyJS = require("../node");
 
 describe("Getters and setters", function() {
     it("Should not accept operator symbols as getter/setter name", function() {
-        var illegalOperators = [
+        [
             "++",
             "--",
             "+",
@@ -42,43 +42,26 @@ describe("Getters and setters", function() {
             "&=",
             "&&",
             "||"
-        ];
-        var generator = function() {
-            var results = [];
-
-            for (var i in illegalOperators) {
-                results.push({
-                    code: "var obj = { get " + illegalOperators[i] + "() { return test; }};",
-                    operator: illegalOperators[i],
-                    method: "get"
-                });
-                results.push({
-                    code: "var obj = { set " + illegalOperators[i] + "(value) { test = value}};",
-                    operator: illegalOperators[i],
-                    method: "set"
-                });
-            }
-
-            return results;
-        };
-        var testCase = function(data) {
-            return function() {
-                UglifyJS.parse(data.code);
-            };
-        };
-        var fail = function(data) {
-            return function(e) {
+        ].reduce(function(tests, illegalOperator) {
+            tests.push({
+                code: "var obj = { get " + illegalOperator + "() { return test; }};",
+                operator: illegalOperator,
+            });
+            tests.push({
+                code: "var obj = { set " + illegalOperator + "(value) { test = value; }};",
+                operator: illegalOperator,
+            });
+            return tests;
+        }, []).forEach(function(test) {
+            assert.throws(function() {
+                UglifyJS.parse(test.code);
+            }, test.operator == "=" ? function(e) {
                 return e instanceof UglifyJS.JS_Parse_Error
-                    && e.message === "Unexpected token: operator «" + data.operator + "»";
-            };
-        };
-        var errorMessage = function(data) {
-            return "Expected but didn't get a syntax error while parsing following line:\n" + data.code;
-        };
-        var tests = generator();
-        for (var i = 0; i < tests.length; i++) {
-            var test = tests[i];
-            assert.throws(testCase(test), fail(test), errorMessage(test));
-        }
+                    && /^Unexpected token: punc «{», expected: punc «.*?»$/.test(e.message);
+            } : function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error
+                    && e.message === "Unexpected token: operator «" + test.operator + "»";
+            }, "Expected but didn't get a syntax error while parsing following line:\n" + test.code);
+        });
     });
 });

test/mocha/number-literal.js

@@ -89,4 +89,13 @@ describe("Number literals", function() {
             }, code);
         });
     });
+    it("Should reject invalid syntax under expression=true", function() {
+        assert.throws(function() {
+            UglifyJS.parse("42.g", {
+                expression: true,
+            });
+        }, function(e) {
+            return e instanceof UglifyJS.JS_Parse_Error;
+        });
+    });
 });

test/mocha/reduce.js

@@ -37,8 +37,7 @@ describe("test/reduce.js", function() {
     it("Should retain setter arguments", function() {
         var result = reduce_test(read("test/input/reduce/setter.js"), {
             compress: {
-                keep_fargs: false,
-                unsafe: true,
+                unsafe_math: true,
             },
             mangle: false,
         }, {
@@ -110,28 +109,24 @@ describe("test/reduce.js", function() {
     });
     it("Should print correct output for irreducible test case", function() {
         var result = reduce_test([
-            "console.log(function f(a) {",
-            "    return f.length;",
-            "}());",
+            "console.log(1 + .1 + .1);",
         ].join("\n"), {
             compress: {
-                keep_fargs: false,
+                unsafe_math: true,
             },
             mangle: false,
         });
         if (result.error) throw result.error;
         assert.strictEqual(result.code, [
             "// (beautified)",
-            "console.log(function f(a) {",
-            "    return f.length;",
-            "}());",
-            "// output: 1",
+            "console.log(1 + .1 + .1);",
+            "// output: 1.2000000000000002",
             "// ",
-            "// minify: 0",
+            "// minify: 1.2",
             "// ",
             "// options: {",
             '//   "compress": {',
-            '//     "keep_fargs": false',
+            '//     "unsafe_math": true',
             "//   },",
             '//   "mangle": false',
             "// }",
@@ -303,8 +298,7 @@ describe("test/reduce.js", function() {
         if (semver.satisfies(process.version, "<=0.10")) return;
         var result = reduce_test(read("test/input/reduce/diff_error.js"), {
             compress: {
-                keep_fargs: false,
-                unsafe: true,
+                unsafe_math: true,
             },
             mangle: false,
         }, {
@@ -313,6 +307,18 @@ describe("test/reduce.js", function() {
         if (result.error) throw result.error;
         assert.strictEqual(result.code, read("test/input/reduce/diff_error.reduced.js"));
     });
+    it("Should maintain valid LHS in destructuring assignments", function() {
+        if (semver.satisfies(process.version, "<6")) return;
+        var result = reduce_test(read("test/input/reduce/destructured_assign.js"), {
+            compress: {
+                unsafe_math: true,
+            },
+            mangle: false,
+            validate: true,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, read("test/input/reduce/destructured_assign.reduced.js"));
+    });
     it("Should handle destructured catch expressions", function() {
         if (semver.satisfies(process.version, "<6")) return;
         var result = reduce_test(read("test/input/reduce/destructured_catch.js"), {

test/mocha/sourcemaps.js

@@ -244,6 +244,39 @@ describe("sourcemaps", function() {
             assert.strictEqual(result.code, '(function(){console.log("hello")}).call(this);');
             assert.strictEqual(result.map, '{"version":3,"sources":["main.coffee"],"names":["console","log"],"mappings":"CAAA,WAAAA,QAAQC,IAAI"}');
         });
+        it("Should not overwrite existing sourcesContent", function() {
+            var result = UglifyJS.minify({
+                "in.js": [
+                    '"use strict";',
+                    "",
+                    "var _window$foo = window.foo,",
+                    "    a = _window$foo[0],",
+                    "    b = _window$foo[1];",
+                ].join("\n"),
+            }, {
+                compress: false,
+                mangle: false,
+                sourceMap: {
+                    content: {
+                        version: 3,
+                        sources: [ "in.js" ],
+                        names: [
+                            "window",
+                            "foo",
+                            "a",
+                            "b",
+                        ],
+                        mappings: ";;kBAAaA,MAAM,CAACC,G;IAAfC,C;IAAGC,C",
+                        file: "in.js",
+                        sourcesContent: [ "let [a, b] = window.foo;\n" ],
+                    },
+                    includeSources: true,
+                },
+            });
+            if (result.error) throw result.error;
+            assert.strictEqual(result.code, '"use strict";var _window$foo=window.foo,a=_window$foo[0],b=_window$foo[1];');
+            assert.strictEqual(result.map, '{"version":3,"sources":["in.js"],"sourcesContent":["let [a, b] = window.foo;\\n"],"names":["window","foo","a","b"],"mappings":"6BAAaA,OAAOC,IAAfC,E,eAAGC,E"}');
+        });
     });
 
     describe("sourceMapInline", function() {

test/reduce.js

@@ -104,15 +104,14 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
 
             // quick ignores
             if (node instanceof U.AST_Accessor) return;
-            if (node instanceof U.AST_Destructured) return;
             if (node instanceof U.AST_Directive) return;
             if (!in_list && node instanceof U.AST_EmptyStatement) return;
             if (node instanceof U.AST_Label) return;
             if (node instanceof U.AST_LabelRef) return;
-            if (!in_list && node instanceof U.AST_SymbolDeclaration) return;
             if (node instanceof U.AST_Toplevel) return;
             var parent = tt.parent();
             if (node instanceof U.AST_SymbolFunarg && parent instanceof U.AST_Accessor) return;
+            if (!in_list && parent.rest !== node && node instanceof U.AST_SymbolDeclaration) return;
 
             // ensure that the _permute prop is a number.
             // can not use `node.start._permute |= 0;` as it will erase fractional part.
@@ -124,7 +123,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
 
             // ignore lvalues
             if (parent instanceof U.AST_Assign && parent.left === node) return;
-            if (parent instanceof U.AST_DestructuredArray) return;
+            if (parent instanceof U.AST_DefaultValue && parent.name === node) return;
             if (parent instanceof U.AST_DestructuredKeyVal && parent.value === node) return;
             if (parent instanceof U.AST_Unary && parent.expression === node) switch (parent.operator) {
               case "++":
@@ -153,6 +152,20 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     node.left,
                     node.right,
                 ][ permute & 1 ];
+                if (expr instanceof U.AST_Destructured) expr = expr.transform(new U.TreeTransformer(function(node, descend) {
+                    if (node instanceof U.AST_DefaultValue) return new U.AST_Assign({
+                        operator: "=",
+                        left: node.name.transform(this),
+                        right: node.value,
+                        start: {},
+                    });
+                    if (node instanceof U.AST_DestructuredKeyVal) return new U.AST_ObjectKeyVal(node);
+                    if (node instanceof U.AST_Destructured) {
+                        node = new (node instanceof U.AST_DestructuredArray ? U.AST_Array : U.AST_Object)(node);
+                        descend(node, this);
+                    }
+                    return node;
+                }));
                 CHANGED = true;
                 return permute < 2 ? expr : wrap_with_console_log(expr);
             }
@@ -211,6 +224,28 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     node.alternative,
                 ][ ((node.start._permute += step) * steps | 0) % 3 ];
             }
+            else if (node instanceof U.AST_DefaultValue) {
+                node.start._permute++;
+                CHANGED = true;
+                return node.name;
+            }
+            else if (node instanceof U.AST_DestructuredArray) {
+                var expr = node.elements[0];
+                if (expr && !(expr instanceof U.AST_Hole)) {
+                    node.start._permute++;
+                    CHANGED = true;
+                    return expr;
+                }
+            }
+            else if (node instanceof U.AST_DestructuredObject) {
+                // first property's value
+                var expr = node.properties[0];
+                if (expr) {
+                    node.start._permute++;
+                    CHANGED = true;
+                    return expr.value;
+                }
+            }
             else if (node instanceof U.AST_Defun) {
                 switch (((node.start._permute += step) * steps | 0) % 2) {
                   case 0:
@@ -304,7 +339,16 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
             }
             else if (node instanceof U.AST_Object) {
                 // first property's value
-                var expr = node.properties[0] instanceof U.AST_ObjectKeyVal && node.properties[0].value;
+                var expr = node.properties[0];
+                if (expr instanceof U.AST_ObjectKeyVal) {
+                    expr = expr.value;
+                } else if (expr instanceof U.AST_Spread) {
+                    expr = expr.expression;
+                } else if (expr && expr.key instanceof U.AST_Node) {
+                    expr = expr.key;
+                } else {
+                    expr = null;
+                }
                 if (expr) {
                     node.start._permute++;
                     CHANGED = true;
@@ -314,7 +358,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
             else if (node instanceof U.AST_PropAccess) {
                 var expr = [
                     node.expression,
-                    node.property instanceof U.AST_Node && node.property,
+                    node.property instanceof U.AST_Node && !(parent instanceof U.AST_Destructured) && node.property,
                 ][ node.start._permute++ % 2 ];
                 if (expr) {
                     CHANGED = true;
@@ -416,15 +460,10 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     CHANGED = true;
                     return List.skip;
                 }
-
-                // skip element/property from (destructured) array/object
-                if (parent instanceof U.AST_Array
-                    || parent instanceof U.AST_Destructured
-                    || parent instanceof U.AST_Object) {
-                    node.start._permute++;
-                    CHANGED = true;
-                    return List.skip;
-                }
+            } else if (parent.rest === node) {
+                node.start._permute++;
+                CHANGED = true;
+                return null;
             }
 
             // replace this node
@@ -627,7 +666,7 @@ function has_loopcontrol(body, loop, label) {
 }
 
 function is_error(result) {
-    return typeof result == "object" && typeof result.name == "string" && typeof result.message == "string";
+    return result && typeof result.name == "string" && typeof result.message == "string";
 }
 
 function is_timed_out(result) {
@@ -636,7 +675,10 @@ function is_timed_out(result) {
 
 function is_statement(node) {
     return node instanceof U.AST_Statement
-        && !(node instanceof U.AST_Arrow || node instanceof U.AST_AsyncFunction || node instanceof U.AST_Function);
+        && !(node instanceof U.AST_Arrow
+            || node instanceof U.AST_AsyncArrow
+            || node instanceof U.AST_AsyncFunction
+            || node instanceof U.AST_Function);
 }
 
 function merge_sequence(array, node) {

test/sandbox.js

@@ -64,7 +64,7 @@ function createContext() {
     }
 }
 
-exports.run_code = function(code, toplevel, timeout) {
+function run_code(code, toplevel, timeout) {
     timeout = timeout || 5000;
     var stdout = "";
     var original_write = process.stdout.write;
@@ -79,7 +79,17 @@ exports.run_code = function(code, toplevel, timeout) {
     } finally {
         process.stdout.write = original_write;
     }
-};
+}
+
+exports.run_code = semver.satisfies(process.version, "0.8") ? function(code, toplevel, timeout) {
+    var stdout = run_code(code, toplevel, timeout);
+    if (typeof stdout != "string" || !/arguments/.test(code)) return stdout;
+    do {
+        var prev = stdout;
+        stdout = run_code(code, toplevel, timeout);
+    } while (prev !== stdout);
+    return stdout;
+} : run_code;
 
 function strip_func_ids(text) {
     return ("" + text).replace(/F[0-9]{6}N/g, "<F<>N>");

test/ufuzz/index.js

@@ -5,7 +5,7 @@
 // bin/uglifyjs s.js -c && bin/uglifyjs s.js -c passes=3 && bin/uglifyjs s.js -c passes=3 -m
 // cat s.js | node && node s.js && bin/uglifyjs s.js -c | node && bin/uglifyjs s.js -c passes=3 | node && bin/uglifyjs s.js -c passes=3 -m | node
 
-require("../../tools/exit");
+require("../../tools/tty");
 
 var UglifyJS = require("../..");
 var randomBytes = require("crypto").randomBytes;
@@ -137,8 +137,11 @@ var SUPPORT = function(matrix) {
     catch_omit_var: "try {} catch {}",
     computed_key: "({[0]: 0});",
     const_block: "var a; { const a = 0; }",
+    default_value: "[ a = 0 ] = [];",
     destructuring: "[] = [];",
     let: "let a;",
+    rest: "var [...a] = [];",
+    rest_object: "var {...a} = {};",
     spread: "[...[]];",
     spread_object: "({...0});",
     trailing_comma: "function f(a,) {}",
@@ -425,18 +428,48 @@ function createArgs(recurmax, stmtDepth, canThrow) {
 function createAssignmentPairs(recurmax, stmtDepth, canThrow, nameLenBefore, was_async) {
     var avoid = [];
     var len = unique_vars.length;
-    var pairs = createPairs(recurmax);
+    var pairs = createPairs(recurmax, !nameLenBefore);
+    pairs.has_rest = nameLenBefore && convertToRest(pairs.names);
     unique_vars.length = len;
     return pairs;
 
-    function createAssignmentValue(recurmax) {
+    function convertToRest(names) {
+        var last = names.length - 1;
+        if (last >= 0 && SUPPORT.rest && rng(20) == 0) {
+            var name = names[last];
+            if (name && name.indexOf("=") < 0) {
+                if (/^[[{]/.test(name)) name = "[ " + name + " ]";
+                names[last] = "..." + name;
+                return true;
+            }
+        }
+    }
+
+    function fill(nameFn, valueFn) {
         var save_async = async;
-        if (was_async != null) async = was_async;
+        if (was_async != null) {
+            async = false;
+            if (save_async || was_async) addAvoidVar("await");
+        }
+        avoid.forEach(addAvoidVar);
         var save_vars = nameLenBefore && VAR_NAMES.splice(nameLenBefore);
-        var value = nameLenBefore && rng(2) ? createValue() : createExpression(recurmax, NO_COMMA, stmtDepth, canThrow);
+        if (nameFn) nameFn();
+        if (was_async != null) {
+            async = was_async;
+            if (save_async || was_async) removeAvoidVar("await");
+        }
+        if (valueFn) valueFn();
         if (save_vars) [].push.apply(VAR_NAMES, save_vars);
+        avoid.forEach(removeAvoidVar);
         async = save_async;
-        return value;
+    }
+
+    function createAssignmentValue(recurmax) {
+        return nameLenBefore && rng(2) ? createValue() : createExpression(recurmax, NO_COMMA, stmtDepth, canThrow);
+    }
+
+    function createDefaultValue(recurmax, noDefault) {
+        return !noDefault && SUPPORT.default_value && rng(20) == 0 ? " = " +  createAssignmentValue(recurmax) : "";
     }
 
     function createKey(recurmax, keys) {
@@ -459,20 +492,22 @@ function createAssignmentPairs(recurmax, stmtDepth, canThrow, nameLenBefore, was
         return name;
     }
 
-    function createPairs(recurmax) {
+    function createPairs(recurmax, noDefault) {
         var names = [], values = [];
         var m = rng(4), n = rng(4);
         if (!nameLenBefore) m = Math.max(m, n, 1);
         for (var i = Math.max(m, n); --i >= 0;) {
             if (i < m && i < n) {
-                createDestructured(recurmax, names, values);
-                continue;
-            }
-            if (i < m) {
-                names.unshift(createName());
-            }
-            if (i < n) {
-                values.unshift(createAssignmentValue(recurmax));
+                createDestructured(recurmax, noDefault, names, values);
+            } else if (i < m) {
+                var name = createName();
+                fill(function() {
+                    names.unshift(name + createDefaultValue(recurmax, noDefault));
+                });
+            } else {
+                fill(null, function() {
+                    values.unshift(createAssignmentValue(recurmax));
+                });
             }
         }
         return {
@@ -481,7 +516,7 @@ function createAssignmentPairs(recurmax, stmtDepth, canThrow, nameLenBefore, was
         };
     }
 
-    function createDestructured(recurmax, names, values) {
+    function createDestructured(recurmax, noDefault, names, values) {
         switch (rng(20)) {
           case 0:
             if (--recurmax < 0) {
@@ -489,20 +524,26 @@ function createAssignmentPairs(recurmax, stmtDepth, canThrow, nameLenBefore, was
                 values.unshift('""');
             } else {
                 var pairs = createPairs(recurmax);
-                while (!rng(10)) {
-                    var index = rng(pairs.names.length + 1);
-                    pairs.names.splice(index, 0, "");
-                    if (index < pairs.values.length) {
-                        pairs.values.splice(index, 0, rng(2) ? createAssignmentValue(recurmax) : "");
-                    } else switch (rng(5)) {
-                      case 0:
-                        pairs.values[index] = createAssignmentValue(recurmax);
-                      case 1:
-                        pairs.values.length = index + 1;
+                var default_value;
+                fill(function() {
+                    default_value = createDefaultValue(recurmax, noDefault);
+                }, function() {
+                    while (!rng(10)) {
+                        var index = rng(pairs.names.length + 1);
+                        pairs.names.splice(index, 0, "");
+                        if (index < pairs.values.length) {
+                            pairs.values.splice(index, 0, rng(2) ? createAssignmentValue(recurmax) : "");
+                        } else switch (rng(5)) {
+                          case 0:
+                            pairs.values[index] = createAssignmentValue(recurmax);
+                          case 1:
+                            pairs.values.length = index + 1;
+                        }
                     }
-                }
-                names.unshift("[ " + pairs.names.join(", ") + " ]");
-                values.unshift("[ " + pairs.values.join(", ") + " ]");
+                    convertToRest(pairs.names);
+                    names.unshift("[ " + pairs.names.join(", ") + " ]" + default_value);
+                    values.unshift("[ " + pairs.values.join(", ") + " ]");
+                });
             }
             break;
           case 1:
@@ -521,33 +562,33 @@ function createAssignmentPairs(recurmax, stmtDepth, canThrow, nameLenBefore, was
                         keys[index] = key;
                     }
                 });
-                var save_async = async;
-                if (was_async != null) {
-                    async = false;
-                    if (save_async || was_async) avoid.push("await");
-                }
-                addAvoidVars(avoid);
-                var save_vars = nameLenBefore && VAR_NAMES.splice(nameLenBefore);
-                names.unshift("{ " + addTrailingComma(pairs.names.map(function(name, index) {
-                    var key = index in keys ? keys[index] : rng(10) && createKey(recurmax, keys);
-                    return key ? key + ": " + name : name;
-                }).join(", ")) + " }");
-                if (was_async != null) {
-                    async = was_async;
-                    if (save_async || was_async) removeAvoidVars([ avoid.pop() ]);
-                }
-                values.unshift("{ " + addTrailingComma(pairs.values.map(function(value, index) {
-                    var key = index in keys ? keys[index] : createKey(recurmax, keys);
-                    return key + ": " + value;
-                }).join(", ")) + " }");
-                if (save_vars) [].push.apply(VAR_NAMES, save_vars);
-                removeAvoidVars(avoid);
-                async = save_async;
+                fill(function() {
+                    var last = pairs.names.length - 1, has_rest = false;
+                    var s = pairs.names.map(function(name, index) {
+                        if (index in keys) return keys[index] + ": " + name;
+                        if (index == last && SUPPORT.rest_object && rng(20) == 0 && name.indexOf("=") < 0) {
+                            has_rest = true;
+                            return "..." + name;
+                        }
+                        return rng(10) == 0 ? name : createKey(recurmax, keys) + ": " + name;
+                    }).join(", ");
+                    if (!has_rest) s = addTrailingComma(s);
+                    names.unshift("{ " + s + " }" + createDefaultValue(recurmax, noDefault));
+                }, function() {
+                    values.unshift("{ " + addTrailingComma(pairs.values.map(function(value, index) {
+                        var key = index in keys ? keys[index] : createKey(recurmax, keys);
+                        return key + ": " + value;
+                    }).join(", ")) + " }");
+                });
             }
             break;
           default:
-            names.unshift(createName());
-            values.unshift(createAssignmentValue(recurmax));
+            var name = createName();
+            fill(function() {
+                names.unshift(name + createDefaultValue(recurmax, noDefault));
+            }, function() {
+                values.unshift(createAssignmentValue(recurmax));
+            });
             break;
         }
     }
@@ -575,8 +616,8 @@ function createBlockVariables(recurmax, stmtDepth, canThrow, fn) {
     }
     unique_vars.length -= 6;
     fn(function() {
-        addAvoidVars(consts);
-        addAvoidVars(lets);
+        consts.forEach(addAvoidVar);
+        lets.forEach(addAvoidVar);
         if (rng(2)) {
             return createDefinitions("const", consts) + "\n" + createDefinitions("let", lets) + "\n";
         } else {
@@ -610,17 +651,17 @@ function createBlockVariables(recurmax, stmtDepth, canThrow, fn) {
           default:
             s += names.map(function(name) {
                 if (type == "let" && !rng(10)) {
-                    removeAvoidVars([ name ]);
+                    removeAvoidVar(name);
                     return name;
                 }
                 var value = createExpression(recurmax, NO_COMMA, stmtDepth, canThrow);
-                removeAvoidVars([ name ]);
+                removeAvoidVar(name);
                 return name + " = " + value;
             }).join(", ") + ";";
             names.length = 0;
             break;
         }
-        removeAvoidVars(names);
+        names.forEach(removeAvoidVar);
         return s;
     }
 }
@@ -659,7 +700,8 @@ function createFunction(recurmax, allowDefun, canThrow, stmtDepth) {
         if (SUPPORT.destructuring && (!allowDefun || !(name in called)) && rng(2)) {
             called[name] = false;
             var pairs = createAssignmentPairs(recurmax, stmtDepth, canThrow, nameLenBefore, save_async);
-            params = addTrailingComma(pairs.names.join(", "));
+            params = pairs.names.join(", ");
+            if (!pairs.has_rest) params = addTrailingComma(params);
             args = addTrailingComma(pairs.values.join(", "));
         } else {
             params = createParams(save_async);
@@ -877,9 +919,9 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
                     unique_vars.length -= 6;
                     if (SUPPORT.computed_key && rng(10) == 0) {
                         s += " catch ({  message: " + message + ", ";
-                        addAvoidVars([ name ]);
+                        addAvoidVar(name);
                         s += "[" + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + "]: " + name;
-                        removeAvoidVars([ name ]);
+                        removeAvoidVar(name);
                         s += " }) { ";
                     } else {
                         s += " catch ({ name: " + name + ", message: " + message + " }) { ";
@@ -1011,7 +1053,7 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
         var s = [];
         switch (rng(5)) {
           case 0:
-            if (SUPPORT.arrow && !async && !name && rng(2)) {
+            if (SUPPORT.arrow && !name && rng(2)) {
                 var args, suffix;
                 (rng(2) ? createBlockVariables : function() {
                     arguments[3]();
@@ -1019,21 +1061,23 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
                     var params;
                     if (SUPPORT.destructuring && rng(2)) {
                         var pairs = createAssignmentPairs(recurmax, stmtDepth, canThrow, nameLenBefore, save_async);
-                        params = addTrailingComma(pairs.names.join(", "));
+                        params = pairs.names.join(", ");
+                        if (!pairs.has_rest) params = addTrailingComma(params);
                         args = addTrailingComma(pairs.values.join(", "));
                     } else {
                         params = createParams(save_async, NO_DUPLICATE);
                     }
+                    params = (async ? "async (" : "(") + params + ") => ";
                     if (defns) {
                         s.push(
-                            "((" + params + ") => {",
+                            "(" + params + "{",
                             strictMode(),
                             defns(),
                             _createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth)
                         );
                         suffix = "})";
                     } else {
-                        s.push("((" + params + ") => ");
+                        s.push("(" + params);
                         switch (rng(10)) {
                           case 0:
                             s.push('(typeof arguments != "undefined" && arguments && arguments[' + rng(3) + "])");
@@ -1441,18 +1485,26 @@ function _createSimpleBinaryExpr(recurmax, noComma, stmtDepth, canThrow) {
 function createTypeofExpr(recurmax, stmtDepth, canThrow) {
     switch (rng(8)) {
       case 0:
-        return "(typeof " + createVarName(MANDATORY, DONT_STORE) + ' === "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
+        return "(typeof " + createVar() + ' === "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
       case 1:
-        return "(typeof " + createVarName(MANDATORY, DONT_STORE) + ' !== "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
+        return "(typeof " + createVar() + ' !== "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
       case 2:
-        return "(typeof " + createVarName(MANDATORY, DONT_STORE) + ' == "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
+        return "(typeof " + createVar() + ' == "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
       case 3:
-        return "(typeof " + createVarName(MANDATORY, DONT_STORE) + ' != "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
+        return "(typeof " + createVar() + ' != "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
       case 4:
-        return "(typeof " + createVarName(MANDATORY, DONT_STORE) + ")";
+        return "(typeof " + createVar() + ")";
       default:
         return "(typeof " + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ")";
     }
+
+    function createVar() {
+        var save_async = async;
+        if (!async && avoid_vars.indexOf("await") >= 0) async = true;
+        var name = createVarName(MANDATORY, DONT_STORE);
+        async = save_async;
+        return name;
+    }
 }
 
 function createValue() {
@@ -1483,15 +1535,13 @@ function createUnaryPostfix() {
     return UNARY_POSTFIX[rng(UNARY_POSTFIX.length)];
 }
 
-function addAvoidVars(names) {
-    avoid_vars = avoid_vars.concat(names);
+function addAvoidVar(name) {
+    avoid_vars.push(name);
 }
 
-function removeAvoidVars(names) {
-    names.forEach(function(name) {
-        var index = avoid_vars.lastIndexOf(name);
-        if (index >= 0) avoid_vars.splice(index, 1);
-    });
+function removeAvoidVar(name) {
+    var index = avoid_vars.lastIndexOf(name);
+    if (index >= 0) avoid_vars.splice(index, 1);
 }
 
 function getVarName(noConst) {
@@ -1664,18 +1714,20 @@ function log(options) {
         }
     }
     errorln("//-------------------------------------------------------------");
-    var reduce_options = JSON.parse(options);
-    reduce_options.validate = true;
-    var reduced = reduce_test(original_code, reduce_options, {
-        verbose: false,
-    }).code;
-    if (reduced) {
-        errorln();
-        errorln("// reduced test case (output will differ)");
-        errorln();
-        errorln(reduced);
-        errorln();
-        errorln("//-------------------------------------------------------------");
+    if (!ok) {
+        var reduce_options = JSON.parse(options);
+        reduce_options.validate = true;
+        var reduced = reduce_test(original_code, reduce_options, {
+            verbose: false,
+        }).code;
+        if (reduced) {
+            errorln();
+            errorln("// reduced test case (output will differ)");
+            errorln();
+            errorln(reduced);
+            errorln();
+            errorln("//-------------------------------------------------------------");
+        }
     }
     errorln("minify(options):");
     errorln(JSON.stringify(JSON.parse(options), null, 2));
@@ -1692,7 +1744,9 @@ function log(options) {
 
 function sort_globals(code) {
     var globals = sandbox.run_code("throw Object.keys(this).sort();" + code);
-    return globals.length ? "var " + globals.join(",") + ";" + code : code;
+    return globals.length ? "var " + globals.map(function(name) {
+        return name + "=" + name;
+    }).join(",") + ";" + code : code;
 }
 
 function fuzzy_match(original, uglified) {
@@ -1709,6 +1763,18 @@ function fuzzy_match(original, uglified) {
     return true;
 }
 
+function is_error_in(ex) {
+    return ex.name == "TypeError" && /'in'/.test(ex.message);
+}
+
+function is_error_spread(ex) {
+    return ex.name == "TypeError" && /Found non-callable @@iterator|is not iterable|undefined is not a function/.test(ex.message);
+}
+
+function is_error_recursion(ex) {
+    return ex.name == "RangeError" && /Invalid string length|Maximum call stack size exceeded/.test(ex.message);
+}
+
 function patch_try_catch(orig, toplevel) {
     var stack = [ {
         code: orig,
@@ -1757,13 +1823,13 @@ function patch_try_catch(orig, toplevel) {
                 });
                 offset += insert.length;
                 code = new_code;
-            } else if (result.name == "TypeError" && /'in'/.test(result.message)) {
+            } else if (is_error_in(result)) {
                 index = result.ufuzz_catch;
                 return orig.slice(0, index) + result.ufuzz_var + ' = new Error("invalid `in`");' + orig.slice(index);
-            } else if (result.name == "TypeError" && /not iterable/.test(result.message)) {
+            } else if (is_error_spread(result)) {
                 index = result.ufuzz_catch;
                 return orig.slice(0, index) + result.ufuzz_var + ' = new Error("spread not iterable");' + orig.slice(index);
-            } else if (result.name == "RangeError" && result.message == "Maximum call stack size exceeded") {
+            } else if (is_error_recursion(result)) {
                 index = result.ufuzz_try;
                 return orig.slice(0, index) + 'throw new Error("skipping infinite recursion");' + orig.slice(index);
             }
@@ -1781,6 +1847,18 @@ var beautify_options = {
     },
 };
 var minify_options = require("./options.json");
+if (typeof sandbox.run_code("A:if (0) B:; else B:;") != "string") {
+    minify_options.forEach(function(o) {
+        if (!("mangle" in o)) o.mangle = {};
+        if (o.mangle) o.mangle.v8 = true;
+    });
+}
+var is_bug_async_arrow_rest = function() {};
+if (SUPPORT.arrow && SUPPORT.async && SUPPORT.rest && typeof sandbox.run_code("async (a = f(...[], b)) => 0;") != "string") {
+    is_bug_async_arrow_rest = function(ex) {
+        return ex.name == "SyntaxError" && ex.message == "Rest parameter must be last formal parameter";
+    };
+}
 if (SUPPORT.destructuring && typeof sandbox.run_code("console.log([ 1 ], {} = 2);") != "string") {
     beautify_options.output.v8 = true;
     minify_options.forEach(function(o) {
@@ -1799,6 +1877,8 @@ for (var round = 1; round <= num_iterations; round++) {
     var orig_result = [ sandbox.run_code(original_code), sandbox.run_code(original_code, true) ];
     errored = typeof orig_result[0] != "string";
     if (errored) {
+        println();
+        println();
         println("//=============================================================");
         println("// original code");
         try_beautify(original_code, false, orig_result[0], println);
@@ -1807,6 +1887,7 @@ for (var round = 1; round <= num_iterations; round++) {
         println("original result:");
         println(orig_result[0]);
         println();
+        if (is_bug_async_arrow_rest(orig_result[0])) continue;
     }
     minify_options.forEach(function(options) {
         var o = JSON.parse(options);
@@ -1838,8 +1919,14 @@ for (var round = 1; round <= num_iterations; round++) {
                 ok = sandbox.same_stdout(orig_result[toplevel ? 3 : 2], uglify_result);
             }
             // ignore difference in error message caused by `in`
+            if (!ok && errored && is_error_in(uglify_result) && is_error_in(original_result)) ok = true;
             // ignore difference in error message caused by spread syntax
+            if (!ok && errored && is_error_spread(uglify_result) && is_error_spread(original_result)) ok = true;
             // ignore difference in depth of termination caused by infinite recursion
+            if (!ok && errored && is_error_recursion(original_result)) {
+                if (is_error_recursion(uglify_result) || typeof uglify_result == "string") ok = true;
+            }
+            // ignore errors above when caught by try-catch
             if (!ok) {
                 var orig_skipped = patch_try_catch(original_code, toplevel);
                 var uglify_skipped = patch_try_catch(uglify_code, toplevel);

test/ufuzz/job.js

@@ -70,7 +70,7 @@ function run() {
 
     function trap(data) {
         stderr += data;
-        if (~stderr.indexOf("\nminify(options):\n")) {
+        if (~stderr.indexOf("!!!!!! Failed... round ")) {
             process.exitCode = 1;
             child.stderr.removeListener("data", trap);
         }

test/ufuzz/options.json

@@ -21,14 +21,16 @@
     },
     {
         "compress": {
+            "hoist_vars": true,
+            "keep_infinity": true,
             "passes": 1e6,
             "unsafe": true
         },
+        "keep_fnames": true,
         "toplevel": true
     },
     {
         "compress": {
-            "keep_fargs": false,
             "passes": 1e6,
             "sequences": 1e6,
             "unsafe": true,

tools/exit.js

@@ -1,15 +0,0 @@
-// workaround for tty output truncation upon process.exit()
-var exit = process.exit;
-process.exit = function() {
-    var args = [].slice.call(arguments);
-    process.once("uncaughtException", function() {
-        (function callback() {
-            if (process.stdout.bufferSize || process.stderr.bufferSize) {
-                setTimeout(callback, 1);
-            } else {
-                exit.apply(process, args);
-            }
-        })();
-    });
-    throw exit;
-};

tools/node.js

@@ -3,11 +3,11 @@ var fs = require("fs");
 exports.FILES = [
     require.resolve("../lib/utils.js"),
     require.resolve("../lib/ast.js"),
-    require.resolve("../lib/parse.js"),
     require.resolve("../lib/transform.js"),
+    require.resolve("../lib/parse.js"),
     require.resolve("../lib/scope.js"),
-    require.resolve("../lib/output.js"),
     require.resolve("../lib/compress.js"),
+    require.resolve("../lib/output.js"),
     require.resolve("../lib/sourcemap.js"),
     require.resolve("../lib/mozilla-ast.js"),
     require.resolve("../lib/propmangle.js"),
@@ -23,6 +23,37 @@ new Function("exports", function() {
     return code.join("\n\n");
 }())(exports);
 
+function to_comment(value) {
+    if (typeof value != "string") value = JSON.stringify(value, function(key, value) {
+        return typeof value == "function" ? "<[ " + value + " ]>" : value;
+    }, 2);
+    return "// " + value.replace(/\n/g, "\n// ");
+}
+
+if (+process.env["UGLIFY_BUG_REPORT"]) exports.minify = function(files, options) {
+    if (typeof options == "undefined") options = "<<undefined>>";
+    var code = [
+        "// UGLIFY_BUG_REPORT",
+        to_comment(options),
+    ];
+    if (typeof files == "string") {
+        code.push("");
+        code.push("//-------------------------------------------------------------")
+        code.push("// INPUT CODE", files);
+    } else for (var name in files) {
+        code.push("");
+        code.push("//-------------------------------------------------------------")
+        code.push(to_comment(name), files[name]);
+    }
+    if (options.sourceMap && options.sourceMap.url) {
+        code.push("");
+        code.push("//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6IiJ9");
+    }
+    var result = { code: code.join("\n") };
+    if (options.sourceMap) result.map = '{"version":3,"sources":[],"names":[],"mappings":""}';
+    return result;
+};
+
 function describe_ast() {
     var out = OutputStream({ beautify: true });
     function doitem(ctor) {

tools/tty.js

@@ -0,0 +1,22 @@
+// workaround for tty output truncation on Node.js
+try {
+    // prevent buffer overflow and other asynchronous bugs
+    process.stdout._handle.setBlocking(true);
+    process.stderr._handle.setBlocking(true);
+} catch (e) {
+    // ensure output buffers are flushed before process termination
+    var exit = process.exit;
+    process.exit = function() {
+        var args = [].slice.call(arguments);
+        process.once("uncaughtException", function() {
+            (function callback() {
+                if (process.stdout.bufferSize || process.stderr.bufferSize) {
+                    setTimeout(callback, 1);
+                } else {
+                    exit.apply(process, args);
+                }
+            })();
+        });
+        throw exit;
+    };
+}