v3.14.5

closes #5212
closes #5215

.github/workflows/build.yml

@@ -10,7 +10,7 @@ jobs:
       matrix:
         options:
           - '-mb braces'
-          - '--ie8 -c'
+          - '--ie -c'
           - '-mc'
           - '-p acorn --toplevel -mco spidermonkey'
           - '--toplevel -mc passes=3,pure_getters,unsafe'

.github/workflows/ci.yml

@@ -7,14 +7,9 @@ jobs:
   test:
     strategy:
       matrix:
-        node: [ '0.8', '0.10', '0.12', '4', '6', '8', '10', '12', '14', latest ]
+        node: [ '0.10', '0.12', '4', '6', '8', '10', '12', '14', '16', latest ]
         os: [ ubuntu-latest, windows-latest ]
         script: [ compress, mocha, release/benchmark, release/jetstream ]
-        exclude:
-          - node: '0.8'
-            script: release/benchmark
-          - node: '0.8'
-            script: release/jetstream
     name: ${{ matrix.node }} ${{ matrix.os }} ${{ matrix.script }}
     runs-on: ${{ matrix.os }}
     env:

.github/workflows/ufuzz.yml

@@ -2,11 +2,14 @@ name: Fuzzing
 on:
   pull_request:
   schedule:
-    - cron: '*/5 * * * *'
+    - cron: '*/15 * * * *'
+  workflow_dispatch:
+  workflow_run:
+    branches: [ master ]
+    types: [ completed ]
+    workflows: [ 'Build testing', CI ]
 env:
   BASE_URL: https://api.github.com/repos/${{ github.repository }}
-  CAUSE: ${{ github.event_name }}
-  RUN_NUM: ${{ github.run_number }}
   TOKEN: ${{ github.token }}
 jobs:
   ufuzz:
@@ -34,8 +37,8 @@ jobs:
         shell: bash
         run: |
           . ./test/release/install.sh
-          if [[ $CAUSE == "schedule" ]]; then
+          if [[ $GITHUB_EVENT_NAME == "pull_request" ]]; then
-            node test/ufuzz/job $BASE_URL $TOKEN $RUN_NUM
-          else
             node test/ufuzz/job 5000
+          else
+            node test/ufuzz/job $BASE_URL $TOKEN $GITHUB_RUN_NUMBER
           fi

README.md

@@ -111,8 +111,8 @@ a double dash to prevent input files being used as option arguments:
     -d, --define <expr>[=value] Global definitions.
     -e, --enclose [arg[:value]] Embed everything in a big function, with configurable
                                 argument(s) & value(s).
-    --ie8                       Support non-standard Internet Explorer 8.
+    --ie                        Support non-standard Internet Explorer.
-                                Equivalent to setting `ie8: true` in `minify()`
+                                Equivalent to setting `ie: true` in `minify()`
                                 for `compress`, `mangle` and `output` options.
                                 By default UglifyJS will not try to be IE-proof.
     --keep-fnames               Do not mangle/drop function names.  Useful for
@@ -502,7 +502,7 @@ if (result.error) throw result.error;
 - `compress` (default: `{}`) — pass `false` to skip compressing entirely.
   Pass an object to specify custom [compress options](#compress-options).
 
-- `ie8` (default: `false`) — set to `true` to support IE8.
+- `ie` (default: `false`) — enable workarounds for Internet Explorer bugs.
 
 - `keep_fnames` (default: `false`) — pass `true` to prevent discarding or mangling
   of function names.  Useful for code relying on `Function.prototype.name`.
@@ -566,7 +566,6 @@ if (result.error) throw result.error;
     },
     nameCache: null, // or specify a name cache object
     toplevel: false,
-    ie8: false,
     warnings: false,
 }
 ```
@@ -795,9 +794,8 @@ to be `false` and all symbol names will be omitted.
   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
+- `typeofs` (default: `true`) — compress `typeof` expressions, e.g.
-  `foo === void 0`.  Note: recommend to set this value to `false` for IE10 and
+  `typeof foo == "undefined" → void 0 === foo`
-  earlier versions due to known issues.
 
 - `unsafe` (default: `false`) — apply "unsafe" transformations (discussion below)
 
@@ -1201,6 +1199,17 @@ To allow for better optimizations, the compiler makes various assumptions:
 - Object properties can be added, removed and modified (not prevented with
   `Object.defineProperty()`, `Object.defineProperties()`, `Object.freeze()`,
   `Object.preventExtensions()` or `Object.seal()`).
+- If array destructuring is present, index-like properties in `Array.prototype`
+  have not been overridden:
+  ```javascript
+  Object.prototype[0] = 42;
+  var [ a ] = [];
+  var { 0: b } = {};
+  // 42 undefined
+  console.log([][0], a);
+  // 42 42
+  console.log({}[0], b);
+  ```
 - Earlier versions of JavaScript will throw `SyntaxError` with the following:
   ```javascript
   ({
@@ -1327,3 +1336,30 @@ To allow for better optimizations, the compiler makes various assumptions:
   // SyntaxError: The left-hand side of a for-of loop may not be 'async'.
   ```
   UglifyJS may modify the input which in turn may suppress those errors.
+- Later versions of Chrome and Node.js will give incorrect results with the
+  following:
+  ```javascript
+  console.log({
+      ...console,
+      get 42() {
+          return "FAIL";
+      },
+      [42]: "PASS",
+  }[42]);
+  // Expected: "PASS"
+  // Actual:   "FAIL"
+  ```
+  UglifyJS may modify the input which in turn may suppress those errors.
+- Earlier versions of JavaScript will throw `TypeError` with the following:
+  ```javascript
+  (function() {
+      {
+          const a = "foo";
+      }
+      {
+          const a = "bar";
+      }
+  })();
+  // TypeError: const 'a' has already been declared
+  ```
+  UglifyJS may modify the input which in turn may suppress those errors.

bin/uglifyjs

@@ -10,7 +10,9 @@ var info = require("../package.json");
 var path = require("path");
 var UglifyJS = require("../tools/node");
 
-var skip_keys = [ "cname", "fixed", "inlined", "parent_scope", "scope", "uses_eval", "uses_with" ];
+var skip_keys = [ "cname", "fixed", "in_arg", "inlined", "length_read", "parent_scope", "redef", "scope", "unused" ];
+var truthy_keys = [ "optional", "pure", "terminal", "uses_arguments", "uses_eval", "uses_with" ];
+
 var files = {};
 var options = {};
 var short_forms = {
@@ -101,7 +103,7 @@ function process_option(name, no_value) {
                 "  --config-file <file>                     Read minify() options from JSON file.",
                 "  -d, --define <expr>[=value]              Global definitions.",
                 "  -e, --enclose [arg[,...][:value[,...]]]  Embed everything in a big function, with configurable argument(s) & value(s).",
-                "  --ie8                                    Support non-standard Internet Explorer 8.",
+                "  --ie                                     Support non-standard Internet Explorer.",
                 "  --keep-fnames                            Do not mangle/drop function names. Useful for code relying on Function.prototype.name.",
                 "  --name-cache <file>                      File to hold mangled name mappings.",
                 "  --rename                                 Force symbol expansion.",
@@ -110,6 +112,7 @@ function process_option(name, no_value) {
                 "  --source-map [options]                   Enable source map/specify source map options.",
                 "  --timings                                Display operations run time on STDERR.",
                 "  --toplevel                               Compress and/or mangle variables in toplevel scope.",
+                "  --v8                                     Support non-standard Chrome & Node.js.",
                 "  --validate                               Perform validation during AST manipulations.",
                 "  --verbose                                Print diagnostic messages.",
                 "  --warn                                   Print warning messages.",
@@ -145,9 +148,11 @@ function process_option(name, no_value) {
         options[name] = read_value();
         break;
       case "annotations":
+      case "ie":
       case "ie8":
       case "timings":
       case "toplevel":
+      case "v8":
       case "validate":
       case "webkit":
         options[name] = true;
@@ -344,9 +349,9 @@ function run() {
                     var list = annotations[node.start.file];
                     var pure = list[node.start.pos];
                     if (!pure) {
-                        var pos = node.start.parens;
+                        var tokens = node.start.parens;
-                        if (pos) for (var i = 0; !pure && i < pos.length; i++) {
+                        if (tokens) for (var i = 0; !pure && i < tokens.length; i++) {
-                            pure = list[pos[i]];
+                            pure = list[tokens[i].pos];
                         }
                     }
                     if (pure) node.pure = pure;
@@ -427,7 +432,7 @@ function run() {
               case "thedef":
                 return symdef(value);
             }
-            if (skip_key(key)) return;
+            if (skip_property(key, value)) return;
             if (value instanceof UglifyJS.AST_Token) return;
             if (value instanceof UglifyJS.Dictionary) return;
             if (value instanceof UglifyJS.AST_Node) {
@@ -516,7 +521,7 @@ function read_file(path, default_value) {
 }
 
 function parse_js(value, options, flag) {
-    if (!options || typeof options != "object") options = {};
+    if (!options || typeof options != "object") options = Object.create(null);
     if (typeof value == "string") try {
         UglifyJS.parse(value, {
             expression: true
@@ -556,8 +561,10 @@ function parse_js(value, options, flag) {
     return options;
 }
 
-function skip_key(key) {
+function skip_property(key, value) {
-    return skip_keys.indexOf(key) >= 0;
+    return skip_keys.indexOf(key) >= 0
+        // only skip truthy_keys if their value is falsy
+        || truthy_keys.indexOf(key) >= 0 && !value;
 }
 
 function symdef(def) {

lib/ast.js

@@ -50,41 +50,39 @@ function DEFNODE(type, props, methods, base) {
     if (base && base.PROPS) props = props.concat(base.PROPS);
     var code = [
         "return function AST_", type, "(props){",
+        // not essential, but speeds up compress by a few percent
+        "this._bits=0;",
         "if(props){",
     ];
     props.forEach(function(prop) {
         code.push("this.", prop, "=props.", prop, ";");
     });
     code.push("}");
-    var proto = base && new base;
+    var proto = Object.create(base && base.prototype);
-    if (proto && proto.initialize || methods && methods.initialize) code.push("this.initialize();");
+    if (methods.initialize || proto.initialize) code.push("this.initialize();");
-    code.push("}");
+    code.push("};");
     var ctor = new Function(code.join(""))();
-    if (proto) {
+    ctor.prototype = proto;
-        ctor.prototype = proto;
-        ctor.BASE = base;
-    }
-    if (base) base.SUBCLASSES.push(ctor);
     ctor.prototype.CTOR = ctor;
-    ctor.PROPS = props || null;
+    ctor.prototype.TYPE = ctor.TYPE = type;
-    ctor.SELF_PROPS = self_props;
+    if (base) {
-    ctor.SUBCLASSES = [];
+        ctor.BASE = base;
-    if (type) {
+        base.SUBCLASSES.push(ctor);
-        ctor.prototype.TYPE = ctor.TYPE = type;
-    }
-    if (methods) for (var name in methods) if (HOP(methods, name)) {
-        if (/^\$/.test(name)) {
-            ctor[name.substr(1)] = methods[name];
-        } else {
-            ctor.prototype[name] = methods[name];
-        }
     }
     ctor.DEFMETHOD = function(name, method) {
         this.prototype[name] = method;
     };
-    if (typeof exports !== "undefined") {
+    ctor.PROPS = props;
-        exports["AST_" + type] = ctor;
+    ctor.SELF_PROPS = self_props;
+    ctor.SUBCLASSES = [];
+    for (var name in methods) if (HOP(methods, name)) {
+        if (/^\$/.test(name)) {
+            ctor[name.substr(1)] = methods[name];
+        } else {
+            ctor.DEFMETHOD(name, methods[name]);
+        }
     }
+    if (typeof exports !== "undefined") exports["AST_" + type] = ctor;
     return ctor;
 }
 
@@ -139,6 +137,52 @@ var AST_Node = DEFNODE("Node", "start end", {
     },
 }, null);
 
+DEF_BITPROPS(AST_Node, [
+    "_optimized",
+    "_squeezed",
+    // AST_Call
+    "call_only",
+    "collapse_scanning",
+    // AST_SymbolRef
+    "defined",
+    "evaluating",
+    "falsy",
+    // AST_SymbolRef
+    "in_arg",
+    // AST_Return
+    "in_bool",
+    // AST_SymbolRef
+    "is_undefined",
+    // AST_LambdaExpression
+    // AST_LambdaDefinition
+    "inlined",
+    // AST_Lambda
+    "length_read",
+    // AST_Yield
+    "nested",
+    // AST_Lambda
+    "new",
+    // AST_Call
+    // AST_PropAccess
+    "optional",
+    // AST_ClassProperty
+    "private",
+    // AST_Call
+    "pure",
+    // AST_Assign
+    "redundant",
+    // AST_ClassProperty
+    "static",
+    // AST_Call
+    // AST_PropAccess
+    "terminal",
+    "truthy",
+    // AST_Scope
+    "uses_eval",
+    // AST_Scope
+    "uses_with",
+]);
+
 (AST_Node.log_function = function(fn, verbose) {
     if (typeof fn != "function") {
         AST_Node.info = AST_Node.warn = noop;
@@ -257,7 +301,7 @@ var AST_SimpleStatement = DEFNODE("SimpleStatement", "body", {
     },
 }, AST_Statement);
 
-var AST_BlockScope = DEFNODE("BlockScope", "enclosed functions make_def parent_scope variables", {
+var AST_BlockScope = DEFNODE("BlockScope", "_var_names enclosed functions make_def parent_scope variables", {
     $documentation: "Base class for all statements introducing a lexical scope",
     $propdoc: {
         enclosed: "[SymbolDef*/S] a list of all symbol definitions that are accessed from this scope or any subscopes",
@@ -488,7 +532,7 @@ var AST_With = DEFNODE("With", "expression", {
 
 /* -----[ scope and functions ]----- */
 
-var AST_Scope = DEFNODE("Scope", "uses_eval uses_with", {
+var AST_Scope = DEFNODE("Scope", "fn_defs may_call_this uses_eval uses_with", {
     $documentation: "Base class for all statements introducing a lexical scope",
     $propdoc: {
         uses_eval: "[boolean/S] tells whether this scope contains a direct call to the global `eval`",
@@ -547,13 +591,13 @@ var AST_Toplevel = DEFNODE("Toplevel", "globals", {
     }
 }, AST_Scope);
 
-var AST_Lambda = DEFNODE("Lambda", "argnames length_read rest uses_arguments", {
+var AST_Lambda = DEFNODE("Lambda", "argnames length_read rest safe_ids uses_arguments", {
     $documentation: "Base class for functions",
     $propdoc: {
         argnames: "[(AST_DefaultValue|AST_Destructured|AST_SymbolFunarg)*] array of function arguments and/or destructured literals",
         length_read: "[boolean/S] whether length property of this function is accessed",
         rest: "[(AST_Destructured|AST_SymbolFunarg)?] rest parameter, or null if absent",
-        uses_arguments: "[boolean/S] whether this function accesses the arguments array",
+        uses_arguments: "[boolean|number/S] whether this function accesses the arguments array",
     },
     each_argname: function(visit) {
         var tw = new TreeWalker(function(node) {
@@ -1293,13 +1337,14 @@ function must_be_expressions(node, prop, allow_spread, allow_hole) {
     });
 }
 
-var AST_Call = DEFNODE("Call", "args expression optional pure", {
+var AST_Call = DEFNODE("Call", "args expression optional pure terminal", {
     $documentation: "A function call expression",
     $propdoc: {
         args: "[AST_Node*] array of arguments",
         expression: "[AST_Node] expression to invoke as function",
         optional: "[boolean] whether the expression is optional chaining",
-        pure: "[string/S] marker for side-effect-free call expression",
+        pure: "[boolean/S] marker for side-effect-free call expression",
+        terminal: "[boolean] whether the chain has ended",
     },
     walk: function(visitor) {
         var node = this;
@@ -1320,6 +1365,7 @@ var AST_New = DEFNODE("New", null, {
     $documentation: "An object instantiation.  Derives from a function call since it has exactly the same properties",
     _validate: function() {
         if (this.optional) throw new Error("optional must be false");
+        if (this.terminal) throw new Error("terminal must be false");
     },
 }, AST_Call);
 
@@ -1342,23 +1388,23 @@ var AST_Sequence = DEFNODE("Sequence", "expressions", {
     },
 });
 
-var AST_PropAccess = DEFNODE("PropAccess", "expression optional property", {
+function root_expr(prop) {
+    while (prop instanceof AST_PropAccess) prop = prop.expression;
+    return prop;
+}
+
+var AST_PropAccess = DEFNODE("PropAccess", "expression optional property terminal", {
     $documentation: "Base class for property access expressions, i.e. `a.foo` or `a[\"foo\"]`",
     $propdoc: {
         expression: "[AST_Node] the “container” expression",
         optional: "[boolean] whether the expression is optional chaining",
         property: "[AST_Node|string] the property to access.  For AST_Dot this is always a plain string, while for AST_Sub it's an arbitrary AST_Node",
+        terminal: "[boolean] whether the chain has ended",
     },
-    getProperty: function() {
+    get_property: function() {
         var p = this.property;
-        if (p instanceof AST_Constant) {
+        if (p instanceof AST_Constant) return p.value;
-            return p.value;
+        if (p instanceof AST_UnaryPrefix && p.operator == "void" && p.expression instanceof AST_Constant) return;
-        }
-        if (p instanceof AST_UnaryPrefix
-            && p.operator == "void"
-            && p.expression instanceof AST_Constant) {
-            return;
-        }
         return p;
     },
     _validate: function() {
@@ -1692,7 +1738,7 @@ var AST_ObjectMethod = DEFNODE("ObjectMethod", null, {
     _validate: function() {
         if (!(this.value instanceof AST_LambdaExpression)) throw new Error("value must be AST_LambdaExpression");
         if (is_arrow(this.value)) throw new Error("value cannot be AST_Arrow or AST_AsyncArrow");
-        if (this.value.name != null) throw new Error("name of class method's lambda must be null");
+        if (this.value.name != null) throw new Error("name of object method's lambda must be null");
     },
 }, AST_ObjectKeyVal);
 
@@ -1749,7 +1795,7 @@ var AST_SymbolVar = DEFNODE("SymbolVar", null, {
     $documentation: "Symbol defining a variable",
 }, AST_SymbolDeclaration);
 
-var AST_SymbolFunarg = DEFNODE("SymbolFunarg", null, {
+var AST_SymbolFunarg = DEFNODE("SymbolFunarg", "unused", {
     $documentation: "Symbol naming a function argument",
 }, AST_SymbolVar);
 
@@ -1763,11 +1809,11 @@ var AST_SymbolLambda = DEFNODE("SymbolLambda", null, {
 
 var AST_SymbolDefClass = DEFNODE("SymbolDefClass", null, {
     $documentation: "Symbol defining a class",
-}, AST_SymbolLet);
+}, AST_SymbolConst);
 
 var AST_SymbolClass = DEFNODE("SymbolClass", null, {
     $documentation: "Symbol naming a class expression",
-}, AST_SymbolLet);
+}, AST_SymbolConst);
 
 var AST_SymbolCatch = DEFNODE("SymbolCatch", null, {
     $documentation: "Symbol naming the exception in catch",
@@ -2001,7 +2047,7 @@ TreeWalker.prototype = {
     },
     find_parent: function(type) {
         var stack = this.stack;
-        for (var i = stack.length; --i >= 0;) {
+        for (var i = stack.length - 1; --i >= 0;) {
             var x = stack[i];
             if (x instanceof type) return x;
         }

lib/minify.js

@@ -76,6 +76,7 @@ function minify(files, options) {
             annotations: undefined,
             compress: {},
             enclose: false,
+            ie: false,
             ie8: false,
             keep_fnames: false,
             mangle: {},
@@ -96,17 +97,18 @@ function minify(files, options) {
         var timings = options.timings && { start: Date.now() };
         if (options.rename === undefined) options.rename = options.compress && options.mangle;
         if (options.annotations !== undefined) set_shorthand("annotations", options, [ "compress", "output" ]);
-        if (options.ie8) set_shorthand("ie8", options, [ "compress", "mangle", "output" ]);
+        if (options.ie8) options.ie = options.ie || options.ie8;
+        if (options.ie) set_shorthand("ie", options, [ "compress", "mangle", "output" ]);
         if (options.keep_fnames) set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
         if (options.toplevel) set_shorthand("toplevel", options, [ "compress", "mangle" ]);
         if (options.v8) set_shorthand("v8", options, [ "mangle", "output" ]);
-        if (options.webkit) set_shorthand("webkit", options, [ "mangle", "output" ]);
+        if (options.webkit) set_shorthand("webkit", options, [ "compress", "mangle", "output" ]);
         var quoted_props;
         if (options.mangle) {
             options.mangle = defaults(options.mangle, {
                 cache: options.nameCache && (options.nameCache.vars || {}),
                 eval: false,
-                ie8: false,
+                ie: false,
                 keep_fnames: false,
                 properties: false,
                 reserved: [],

lib/mozilla-ast.js

@@ -556,7 +556,9 @@
             return node;
         },
         ChainExpression: function(M) {
-            return from_moz(M.expression);
+            var node = from_moz(M.expression);
+            node.terminal = true;
+            return node;
         },
     };
 
@@ -868,7 +870,7 @@
 
     def_to_moz(AST_PropAccess, function To_Moz_MemberExpression(M) {
         var computed = M instanceof AST_Sub;
-        return {
+        var expr = {
             type: "MemberExpression",
             object: to_moz(M.expression),
             computed: computed,
@@ -878,6 +880,10 @@
                 name: M.property,
             },
         };
+        return M.terminal ? {
+            type: "ChainExpression",
+            expression: expr,
+        } : expr;
     });
 
     def_to_moz(AST_Unary, function To_Moz_Unary(M) {
@@ -1134,58 +1140,54 @@
     }
 
     function map(moztype, mytype, propmap) {
-        var moz_to_me = "function From_Moz_" + moztype + "(M){\n";
+        var moz_to_me = [
-        moz_to_me += "return new U2." + mytype.name + "({\n" +
+            "start: my_start_token(M)",
-            "start: my_start_token(M),\n" +
+            "end: my_end_token(M)",
-            "end: my_end_token(M)";
+        ];
-
+        var me_to_moz = [
-        var me_to_moz = "function To_Moz_" + moztype + "(M){\n";
+            "type: " + JSON.stringify(moztype),
-        me_to_moz += "return {\n" +
+        ];
-            "type: " + JSON.stringify(moztype);
 
         if (propmap) propmap.split(/\s*,\s*/).forEach(function(prop) {
             var m = /([a-z0-9$_]+)(=|@|>|%)([a-z0-9$_]+)/i.exec(prop);
             if (!m) throw new Error("Can't understand property map: " + prop);
             var moz = m[1], how = m[2], my = m[3];
-            moz_to_me += ",\n" + my + ": ";
-            me_to_moz += ",\n" + moz + ": ";
             switch (how) {
               case "@":
-                moz_to_me += "M." + moz + ".map(from_moz)";
+                moz_to_me.push(my + ": M." + moz + ".map(from_moz)");
-                me_to_moz += "M." +  my + ".map(to_moz)";
+                me_to_moz.push(moz + ": M." +  my + ".map(to_moz)");
                 break;
               case ">":
-                moz_to_me += "from_moz(M." + moz + ")";
+                moz_to_me.push(my + ": from_moz(M." + moz + ")");
-                me_to_moz += "to_moz(M." + my + ")";
+                me_to_moz.push(moz + ": to_moz(M." + my + ")");
                 break;
               case "=":
-                moz_to_me += "M." + moz;
+                moz_to_me.push(my + ": M." + moz);
-                me_to_moz += "M." + my;
+                me_to_moz.push(moz + ": M." + my);
                 break;
               case "%":
-                moz_to_me += "from_moz(M." + moz + ").body";
+                moz_to_me.push(my + ": from_moz(M." + moz + ").body");
-                me_to_moz += "to_moz_block(M)";
+                me_to_moz.push(moz + ": to_moz_block(M)");
                 break;
               default:
                 throw new Error("Can't understand operator in propmap: " + prop);
             }
         });
 
-        moz_to_me += "\n})\n}";
+        MOZ_TO_ME[moztype] = new Function("U2", "my_start_token", "my_end_token", "from_moz", [
-        me_to_moz += "\n}\n}";
+            "return function From_Moz_" + moztype + "(M) {",
-
+            "    return new U2.AST_" + mytype.TYPE + "({",
-        //moz_to_me = parse(moz_to_me).print_to_string({ beautify: true });
+            moz_to_me.join(",\n"),
-        //me_to_moz = parse(me_to_moz).print_to_string({ beautify: true });
+            "    });",
-        //console.log(moz_to_me);
+            "};",
-
+        ].join("\n"))(exports, my_start_token, my_end_token, from_moz);
-        moz_to_me = new Function("U2", "my_start_token", "my_end_token", "from_moz", "return(" + moz_to_me + ")")(
+        def_to_moz(mytype, new Function("to_moz", "to_moz_block", "to_moz_scope", [
-            exports, my_start_token, my_end_token, from_moz
+            "return function To_Moz_" + moztype + "(M) {",
-        );
+            "    return {",
-        me_to_moz = new Function("to_moz", "to_moz_block", "to_moz_scope", "return(" + me_to_moz + ")")(
+            me_to_moz.join(",\n"),
-            to_moz, to_moz_block, to_moz_scope
+            "    };",
-        );
+            "};",
-        MOZ_TO_ME[moztype] = moz_to_me;
+        ].join("\n"))(to_moz, to_moz_block, to_moz_scope));
-        def_to_moz(mytype, me_to_moz);
     }
 
     var FROM_MOZ_STACK = null;

lib/output.js

@@ -56,7 +56,7 @@ function OutputStream(options) {
         braces           : false,
         comments         : false,
         galio            : false,
-        ie8              : false,
+        ie               : false,
         indent_level     : 4,
         indent_start     : 0,
         inline_script    : true,
@@ -193,7 +193,7 @@ function OutputStream(options) {
               case "\t": return "\\t";
               case "\b": return "\\b";
               case "\f": return "\\f";
-              case "\x0B": return options.ie8 ? "\\x0B" : "\\v";
+              case "\x0B": return options.ie ? "\\x0B" : "\\v";
               case "\u2028": return "\\u2028";
               case "\u2029": return "\\u2029";
               case "\ufeff": return "\\ufeff";
@@ -790,35 +790,44 @@ function OutputStream(options) {
         if (p instanceof AST_Unary) return true;
     });
 
+    function need_chain_parens(node, parent) {
+        if (!node.terminal) return false;
+        if (!(parent instanceof AST_Call || parent instanceof AST_PropAccess)) return false;
+        return parent.expression === node;
+    }
+
     PARENS(AST_PropAccess, function(output) {
         var node = this;
         var p = output.parent();
-        if (p instanceof AST_New && p.expression === node) {
+        // i.e. new (foo().bar)
-            // i.e. new (foo().bar)
+        //
-            //
+        // if there's one call into this subtree, then we need
-            // if there's one call into this subtree, then we need
+        // parens around it too, otherwise the call will be
-            // parens around it too, otherwise the call will be
+        // interpreted as passing the arguments to the upper New
-            // interpreted as passing the arguments to the upper New
+        // expression.
-            // expression.
+        if (p instanceof AST_New && p.expression === node && root_expr(node).TYPE == "Call") return true;
-            do {
+        // (foo?.bar)()
-                node = node.expression;
+        // (foo?.bar).baz
-            } while (node instanceof AST_PropAccess);
+        // new (foo?.bar)()
-            return node.TYPE == "Call";
+        return need_chain_parens(node, p);
-        }
     });
 
     PARENS(AST_Call, function(output) {
+        var node = this;
         var p = output.parent();
-        if (p instanceof AST_New) return p.expression === this;
+        if (p instanceof AST_New) return p.expression === node;
         // https://bugs.webkit.org/show_bug.cgi?id=123506
-        if (output.option("webkit")) {
+        if (output.option("webkit")
+            && node.expression instanceof AST_Function
+            && p instanceof AST_PropAccess
+            && p.expression === node) {
             var g = output.parent(1);
-            return this.expression instanceof AST_Function
+            if (g instanceof AST_Assign && g.left === p) return true;
-                && p instanceof AST_PropAccess
-                && p.expression === this
-                && g instanceof AST_Assign
-                && g.left === p;
         }
+        // (foo?.())()
+        // (foo?.()).bar
+        // new (foo?.())()
+        return need_chain_parens(node, p);
     });
 
     PARENS(AST_New, function(output) {
@@ -965,7 +974,6 @@ function OutputStream(options) {
     DEFPRINT(AST_Do, function(output) {
         var self = this;
         output.print("do");
-        output.space();
         make_block(self.body, output);
         output.space();
         output.print("while");
@@ -982,7 +990,6 @@ function OutputStream(options) {
         output.with_parens(function() {
             self.condition.print(output);
         });
-        output.space();
         force_statement(self.body, output);
     });
     DEFPRINT(AST_For, function(output) {
@@ -1012,7 +1019,6 @@ function OutputStream(options) {
                 self.step.print(output);
             }
         });
-        output.space();
         force_statement(self.body, output);
     });
     function print_for_enum(prefix, infix) {
@@ -1027,7 +1033,6 @@ function OutputStream(options) {
                 output.space();
                 self.object.print(output);
             });
-            output.space();
             force_statement(self.body, output);
         };
     }
@@ -1041,7 +1046,6 @@ function OutputStream(options) {
         output.with_parens(function() {
             self.expression.print(output);
         });
-        output.space();
         force_statement(self.body, output);
     });
     DEFPRINT(AST_ExportDeclaration, function(output) {
@@ -1148,8 +1152,9 @@ function OutputStream(options) {
         });
     }
     function print_arrow(self, output) {
-        if (self.argnames.length == 1 && self.argnames[0] instanceof AST_SymbolFunarg && !self.rest) {
+        var argname = self.argnames.length == 1 && !self.rest && self.argnames[0];
-            self.argnames[0].print(output);
+        if (argname instanceof AST_SymbolFunarg && argname.name != "yield") {
+            argname.print(output);
         } else {
             print_funargs(self, output);
         }
@@ -1280,7 +1285,7 @@ function OutputStream(options) {
     function make_then(self, output) {
         var b = self.body;
         if (output.option("braces") && !(b instanceof AST_Const || b instanceof AST_Let)
-            || output.option("ie8") && b instanceof AST_Do)
+            || output.option("ie") && b instanceof AST_Do)
             return make_block(b, output);
         // The squeezer replaces "block"-s that contain only a single
         // statement with the statement itself; technically, the AST
@@ -1310,16 +1315,16 @@ function OutputStream(options) {
         output.with_parens(function() {
             self.condition.print(output);
         });
-        output.space();
         if (self.alternative) {
             make_then(self, output);
             output.space();
             output.print("else");
-            output.space();
+            if (self.alternative instanceof AST_If) {
-            if (self.alternative instanceof AST_If)
+                output.space();
                 self.alternative.print(output);
-            else
+            } else {
                 force_statement(self.alternative, output);
+            }
         } else {
             force_statement(self.body, output);
         }
@@ -1460,7 +1465,7 @@ function OutputStream(options) {
             parent = output.parent(level++);
             if (parent instanceof AST_Call && parent.expression === node) return;
         } while (parent instanceof AST_PropAccess && parent.expression === node);
-        output.print(typeof self.pure == "string" ? "/*" + self.pure + "*/" : "/*@__PURE__*/");
+        output.print("/*@__PURE__*/");
     }
     function print_call_args(self, output) {
         if (self.expression instanceof AST_Call || self.expression instanceof AST_Lambda) {
@@ -1505,7 +1510,7 @@ function OutputStream(options) {
         var expr = self.expression;
         expr.print(output);
         var prop = self.property;
-        if (output.option("ie8") && RESERVED_WORDS[prop]) {
+        if (output.option("ie") && RESERVED_WORDS[prop]) {
             output.print(self.optional ? "?.[" : "[");
             output.add_mapping(self.end);
             output.print_string(prop);
@@ -1619,7 +1624,19 @@ function OutputStream(options) {
         var self = this;
         var key = print_property_key(self, output);
         var value = self.value;
-        if (key && value instanceof AST_SymbolDeclaration && key == get_symbol_name(value)) return;
+        if (key) {
+            if (value instanceof AST_DefaultValue) {
+                if (value.name instanceof AST_Symbol && key == get_symbol_name(value.name)) {
+                    output.space();
+                    output.print("=");
+                    output.space();
+                    value.value.print(output);
+                    return;
+                }
+            } else if (value instanceof AST_Symbol) {
+                if (key == get_symbol_name(value)) return;
+            }
+        }
         output.colon();
         value.print(output);
     });
@@ -1668,28 +1685,21 @@ function OutputStream(options) {
 
     function print_property_key(self, output) {
         var key = self.key;
-        if (key instanceof AST_Node) {
+        if (key instanceof AST_Node) return output.with_square(function() {
-            output.with_square(function() {
+            key.print(output);
-                key.print(output);
+        });
-            });
+        var quote = self.start && self.start.quote;
-        } else if (output.option("quote_keys")) {
+        if (output.option("quote_keys") || quote && output.option("keep_quoted_props")) {
-            output.print_string(key);
+            output.print_string(key, quote);
         } else if ("" + +key == key && key >= 0) {
             output.print(make_num(key));
+        } else if (self.private) {
+            output.print_name(key);
+        } else if (RESERVED_WORDS[key] ? !output.option("ie") : is_identifier_string(key)) {
+            output.print_name(key);
+            return key;
         } else {
-            var quote = self.start && self.start.quote;
+            output.print_string(key, quote);
-            if (self.private) {
-                output.print_name(key);
-            } else if (RESERVED_WORDS[key] ? !output.option("ie8") : is_identifier_string(key)) {
-                if (quote && output.option("keep_quoted_props")) {
-                    output.print_string(key, quote);
-                } else {
-                    output.print_name(key);
-                    return key;
-                }
-            } else {
-                output.print_string(key, quote);
-            }
         }
     }
     DEFPRINT(AST_ObjectKeyVal, function(output) {
@@ -1821,6 +1831,7 @@ function OutputStream(options) {
         } else if (stat instanceof AST_EmptyStatement) {
             output.force_semicolon();
         } else {
+            output.space();
             stat.print(output);
         }
     }
@@ -1869,6 +1880,7 @@ function OutputStream(options) {
     }
 
     function make_block(stmt, output) {
+        output.space();
         if (stmt instanceof AST_EmptyStatement) {
             print_braced_empty(stmt, output);
         } else if (stmt instanceof AST_BlockStatement) {
@@ -1920,7 +1932,11 @@ function OutputStream(options) {
         output.add_mapping(this.start);
     });
 
-    DEFMAP([ AST_DestructuredKeyVal, AST_ObjectProperty ], function(output) {
+    DEFMAP([
+        AST_ClassProperty,
+        AST_DestructuredKeyVal,
+        AST_ObjectProperty,
+    ], function(output) {
         if (typeof this.key == "string") output.add_mapping(this.start, this.key);
     });
 })();

lib/parse.js

@@ -44,10 +44,10 @@
 
 "use strict";
 
-var KEYWORDS = "break case catch class const continue debugger default delete do else extends finally for function if in instanceof let new return switch throw try typeof var void while with";
+var KEYWORDS = "break case catch class const continue debugger default delete do else extends finally for function if in instanceof new return switch throw try typeof var void while with";
 var KEYWORDS_ATOM = "false null true";
 var RESERVED_WORDS = [
-    "abstract async await boolean byte char double enum export final float goto implements import int interface long native package private protected public short static super synchronized this throws transient volatile yield",
+    "abstract async await boolean byte char double enum export final float goto implements import int interface let long native package private protected public short static super synchronized this throws transient volatile yield",
     KEYWORDS_ATOM,
     KEYWORDS,
 ].join(" ");
@@ -124,7 +124,7 @@ var PUNC_AFTER_EXPRESSION = PUNC_SEPARATORS + PUNC_CLOSERS;
 var PUNC_BEFORE_EXPRESSION = PUNC_OPENERS + PUNC_SEPARATORS;
 var PUNC_CHARS = PUNC_BEFORE_EXPRESSION + "`" + PUNC_CLOSERS;
 var WHITESPACE_CHARS = NEWLINE_CHARS + " \u00a0\t\f\u000b\u200b\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000\uFEFF";
-var NON_IDENTIFIER_CHARS = makePredicate(characters("./'\"" + OPERATOR_CHARS + PUNC_CHARS + WHITESPACE_CHARS));
+var NON_IDENTIFIER_CHARS = makePredicate(characters("./'\"#" + OPERATOR_CHARS + PUNC_CHARS + WHITESPACE_CHARS));
 
 NEWLINE_CHARS = makePredicate(characters(NEWLINE_CHARS));
 OPERATOR_CHARS = makePredicate(characters(OPERATOR_CHARS));
@@ -242,10 +242,10 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
         read_template   : with_eof_error("Unterminated template literal", function(strings) {
             var s = "";
             for (;;) {
-                var ch = next(true, true);
+                var ch = read();
                 switch (ch) {
                   case "\\":
-                    ch += next(true, true);
+                    ch += read();
                     break;
                   case "`":
                     strings.push(s);
@@ -260,6 +260,11 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
                 }
                 s += ch;
             }
+
+            function read() {
+                var ch = next(true, true);
+                return ch == "\r" ? "\n" : ch;
+            }
         }),
     };
     var prev_was_dot = false;
@@ -468,7 +473,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
     });
 
     function read_name() {
-        var backslash = false, name = "", ch, escaped = false, hex;
+        var backslash = false, ch, escaped = false, name = peek() == "#" ? next() : "";
         while (ch = peek()) {
             if (!backslash) {
                 if (ch == "\\") escaped = backslash = true, next();
@@ -483,7 +488,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
             }
         }
         if (KEYWORDS[name] && escaped) {
-            hex = name.charCodeAt(0).toString(16).toUpperCase();
+            var hex = name.charCodeAt(0).toString(16).toUpperCase();
             name = "\\u" + "0000".substr(hex.length) + hex + name.slice(1);
         }
         return name;
@@ -618,7 +623,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
             if (PUNC_CHARS[ch]) return token("punc", next());
             if (looking_at("=>")) return token("punc", next() + next());
             if (OPERATOR_CHARS[ch]) return read_operator();
-            if (code == 92 || !NON_IDENTIFIER_CHARS[ch]) return read_word();
+            if (code == 35 || code == 92 || !NON_IDENTIFIER_CHARS[ch]) return read_word();
             break;
         }
         parse_error("Unexpected character '" + ch + "'");
@@ -862,6 +867,15 @@ function parse($TEXT, options) {
                     next();
                     return import_();
                 }
+                break;
+              case "let":
+                if (is_vardefs()) {
+                    next();
+                    var node = let_();
+                    semicolon();
+                    return node;
+                }
+                break;
               case "yield":
                 if (S.in_generator) return simple_statement();
                 break;
@@ -947,12 +961,6 @@ function parse($TEXT, options) {
                 next();
                 return if_();
 
-              case "let":
-                next();
-                var node = let_();
-                semicolon();
-                return node;
-
               case "return":
                 if (S.in_function == 0 && !options.bare_returns)
                     croak("'return' outside of function");
@@ -1192,7 +1200,7 @@ function parse($TEXT, options) {
         if (await || !is("punc", ";")) {
             init = is("keyword", "const")
                 ? (next(), const_(true))
-                : is("keyword", "let")
+                : is("name", "let") && is_vardefs()
                 ? (next(), let_(true))
                 : is("keyword", "var")
                 ? (next(), var_(true))
@@ -1308,6 +1316,11 @@ function parse($TEXT, options) {
         }
         if (node instanceof AST_SymbolFunarg) return node;
         if (node instanceof AST_SymbolRef) return new AST_SymbolFunarg(node);
+        if (node instanceof AST_Yield) return new AST_SymbolFunarg({
+            start: node.start,
+            name: "yield",
+            end: node.end,
+        });
         token_error(node.start, "Invalid arrow parameter");
     }
 
@@ -1334,21 +1347,19 @@ function parse($TEXT, options) {
         if (is("punc", "{")) {
             body = block_();
             value = null;
-            if (S.input.has_directive("use strict")) {
-                argnames.forEach(strict_verify_symbol);
-            }
         } else {
             body = [];
             handle_regexp();
             value = maybe_assign();
         }
+        var is_strict = S.input.has_directive("use strict");
         S.input.pop_directives_stack();
         --S.in_function;
         S.in_loop = loop;
         S.labels = labels;
         S.in_generator = was_gen;
         S.in_async = was_async;
-        return new (async ? AST_AsyncArrow : AST_Arrow)({
+        var node = new (async ? AST_AsyncArrow : AST_Arrow)({
             start: start,
             argnames: argnames,
             rest: rest,
@@ -1356,6 +1367,8 @@ function parse($TEXT, options) {
             value: value,
             end: prev(),
         });
+        if (is_strict) node.each_argname(strict_verify_symbol);
+        return node;
     }
 
     var function_ = function(ctor) {
@@ -1388,23 +1401,24 @@ function parse($TEXT, options) {
         S.in_loop = 0;
         S.labels = [];
         var body = block_();
-        if (S.input.has_directive("use strict")) {
+        var is_strict = 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;
         S.in_loop = loop;
         S.labels = labels;
         S.in_generator = was_gen;
         S.in_async = was_async;
-        return new ctor({
+        var node = new ctor({
             name: name,
             argnames: argnames,
             rest: argnames.rest || null,
             body: body
         });
+        if (is_strict) {
+            if (name) strict_verify_symbol(name);
+            node.each_argname(strict_verify_symbol);
+        }
+        return node;
     };
 
     function if_() {
@@ -1534,12 +1548,18 @@ function parse($TEXT, options) {
     }
 
     var export_decl = embed_tokens(function() {
-        if (is("name", "async")) {
+        if (is("name")) switch (S.token.value) {
+          case "async":
             next();
             expect_token("keyword", "function");
             if (!is("operator", "*")) return function_(AST_AsyncDefun);
             next();
             return function_(AST_AsyncGeneratorDefun);
+          case "let":
+            next();
+            var node = let_();
+            semicolon();
+            return node;
         } else if (is("keyword")) switch (S.token.value) {
           case "class":
             next();
@@ -1554,11 +1574,6 @@ function parse($TEXT, options) {
             if (!is("operator", "*")) return function_(AST_Defun);
             next();
             return function_(AST_GeneratorDefun);
-          case "let":
-            next();
-            var node = let_();
-            semicolon();
-            return node;
           case "var":
             next();
             var node = var_();
@@ -1719,6 +1734,11 @@ function parse($TEXT, options) {
         return a;
     }
 
+    function is_vardefs() {
+        var token = peek();
+        return is_token(token, "name") || is_token(token, "punc", "[") || is_token(token, "punc", "{");
+    }
+
     var const_ = function(no_in) {
         return new AST_Const({
             start       : prev(),
@@ -1817,10 +1837,7 @@ function parse($TEXT, options) {
         if (is("punc")) {
             switch (start.value) {
               case "`":
-                var tmpl = template(null);
+                return subscripts(template(null), allow_calls);
-                tmpl.start = start;
-                tmpl.end = prev();
-                return subscripts(tmpl, allow_calls);
               case "(":
                 next();
                 if (is("punc", ")")) {
@@ -2132,7 +2149,7 @@ function parse($TEXT, options) {
     }
 
     function strict_verify_symbol(sym) {
-        if (sym.name == "arguments" || sym.name == "eval")
+        if (sym.name == "arguments" || sym.name == "eval" || sym.name == "let")
             token_error(sym.start, "Unexpected " + sym.name + " in strict mode");
     }
 
@@ -2229,6 +2246,7 @@ function parse($TEXT, options) {
     }
 
     function template(tag) {
+        var start = tag ? tag.start : S.token;
         var read = S.input.context().read_template;
         var strings = [];
         var expressions = [];
@@ -2239,72 +2257,73 @@ function parse($TEXT, options) {
         }
         next();
         return new AST_Template({
+            start: start,
             expressions: expressions,
             strings: strings,
             tag: tag,
+            end: prev(),
         });
     }
 
-    var subscripts = function(expr, allow_calls, optional) {
+    function subscripts(expr, allow_calls) {
         var start = expr.start;
-        if (is("punc", "[")) {
+        var optional = null;
-            next();
+        while (true) {
-            var prop = expression();
+            if (is("operator", "?") && is_token(peek(), "punc", ".")) {
-            expect("]");
+                next();
-            return subscripts(new AST_Sub({
+                next();
-                start: start,
+                optional = expr;
-                optional: optional,
+            }
-                expression: expr,
+            if (is("punc", "[")) {
-                property: prop,
+                next();
-                end: prev(),
+                var prop = expression();
-            }), allow_calls);
+                expect("]");
-        }
+                expr = new AST_Sub({
-        if (allow_calls && is("punc", "(")) {
+                    start: start,
-            next();
+                    optional: optional === expr,
-            var call = new AST_Call({
+                    expression: expr,
-                start: start,
+                    property: prop,
-                optional: optional,
+                    end: prev(),
-                expression: expr,
+                });
-                args: expr_list(")", !options.strict),
+            } else if (allow_calls && is("punc", "(")) {
-                end: prev(),
+                next();
-            });
+                expr = new AST_Call({
-            return subscripts(call, true);
+                    start: start,
-        }
+                    optional: optional === expr,
-        if (optional || is("punc", ".")) {
+                    expression: expr,
-            if (!optional) next();
+                    args: expr_list(")", !options.strict),
-            return subscripts(new AST_Dot({
+                    end: prev(),
-                start: start,
+                });
-                optional: optional,
+            } else if (optional === expr || is("punc", ".")) {
-                expression: expr,
+                if (optional !== expr) next();
-                property: as_name(),
+                expr = new AST_Dot({
-                end: prev(),
+                    start: start,
-            }), allow_calls);
+                    optional: optional === expr,
-        }
+                    expression: expr,
-        if (is("punc", "`")) {
+                    property: as_name(),
-            var tmpl = template(expr);
+                    end: prev(),
-            tmpl.start = expr.start;
+                });
-            tmpl.end = prev();
+            } else if (is("punc", "`")) {
-            return subscripts(tmpl, allow_calls);
+                if (optional) croak("Invalid template on optional chain");
-        }
+                expr = template(expr);
-        if (is("operator", "?") && is_token(peek(), "punc", ".")) {
+            } else {
-            next();
+                break;
-            next();
+            }
-            return subscripts(expr, allow_calls, true);
         }
+        if (optional) expr.terminal = true;
         if (expr instanceof AST_Call && !expr.pure) {
             var start = expr.start;
             var comments = start.comments_before;
             var i = HOP(start, "comments_before_length") ? start.comments_before_length : comments.length;
             while (--i >= 0) {
-                var match = /[@#]__PURE__/.exec(comments[i].value);
+                if (/[@#]__PURE__/.test(comments[i].value)) {
-                if (match) {
+                    expr.pure = true;
-                    expr.pure = match[0];
                     break;
                 }
             }
         }
         return expr;
-    };
+    }
 
     function maybe_unary(no_in) {
         var start = S.token;

lib/propmangle.js

@@ -44,7 +44,7 @@
 "use strict";
 
 var builtins = function() {
-    var names = [];
+    var names = new Dictionary();
     // NaN will be included due to Number.NaN
     [
         "null",
@@ -72,10 +72,10 @@ var builtins = function() {
             Object.getOwnPropertyNames(ctor.prototype).map(add);
         }
     });
-    return makePredicate(names);
+    return names;
 
     function add(name) {
-        names.push(name);
+        names.set(name, true);
     }
 }();
 
@@ -116,9 +116,9 @@ function mangle_properties(ast, options) {
         reserved: null,
     }, true);
 
-    var reserved = Object.create(options.builtins ? null : builtins);
+    var reserved = options.builtins ? new Dictionary() : builtins.clone();
     if (Array.isArray(options.reserved)) options.reserved.forEach(function(name) {
-        reserved[name] = true;
+        reserved.set(name, true);
     });
 
     var cname = -1;
@@ -126,7 +126,7 @@ function mangle_properties(ast, options) {
     if (options.cache) {
         cache = options.cache.props;
         cache.each(function(name) {
-            reserved[name] = true;
+            reserved.set(name, true);
         });
     } else {
         cache = new Dictionary();
@@ -141,8 +141,8 @@ function mangle_properties(ast, options) {
     var debug_suffix;
     if (debug) debug_suffix = options.debug === true ? "" : options.debug;
 
-    var names_to_mangle = Object.create(null);
+    var names_to_mangle = new Dictionary();
-    var unmangleable = Object.create(reserved);
+    var unmangleable = reserved.clone();
 
     // step 1: find candidates to mangle
     ast.walk(new TreeWalker(function(node) {
@@ -211,20 +211,20 @@ function mangle_properties(ast, options) {
     // only function declarations after this line
 
     function can_mangle(name) {
-        if (unmangleable[name]) return false;
+        if (unmangleable.has(name)) return false;
         if (/^-?[0-9]+(\.[0-9]+)?(e[+-][0-9]+)?$/.test(name)) return false;
         return true;
     }
 
     function should_mangle(name) {
-        if (reserved[name]) return false;
+        if (reserved.has(name)) return false;
         if (regex && !regex.test(name)) return false;
-        return cache.has(name) || names_to_mangle[name];
+        return cache.has(name) || names_to_mangle.has(name);
     }
 
     function add(name) {
-        if (can_mangle(name)) names_to_mangle[name] = true;
+        if (can_mangle(name)) names_to_mangle.set(name, true);
-        if (!should_mangle(name)) unmangleable[name] = true;
+        if (!should_mangle(name)) unmangleable.set(name, true);
     }
 
     function mangle(name) {

lib/scope.js

@@ -44,9 +44,9 @@
 "use strict";
 
 function SymbolDef(id, scope, orig, init) {
+    this._bits = 0;
+    this.defun = undefined;
     this.eliminated = 0;
-    this.exported = false;
-    this.global = false;
     this.id = id;
     this.init = init;
     this.mangled_name = null;
@@ -54,8 +54,8 @@ function SymbolDef(id, scope, orig, init) {
     this.orig = [ orig ];
     this.references = [];
     this.replaced = 0;
+    this.safe_ids = undefined;
     this.scope = scope;
-    this.undeclared = false;
 }
 
 SymbolDef.prototype = {
@@ -80,15 +80,16 @@ SymbolDef.prototype = {
         }
     },
     redefined: function() {
-        var scope = this.defun;
+        var self = this;
+        var scope = self.defun;
         if (!scope) return;
-        var name = this.name;
+        var name = self.name;
         var def = scope.variables.get(name)
             || scope instanceof AST_Toplevel && scope.globals.get(name)
-            || this.orig[0] instanceof AST_SymbolConst && find_if(function(def) {
+            || self.orig[0] instanceof AST_SymbolConst && find_if(function(def) {
                 return def.name == name;
             }, scope.enclosed);
-        if (def && def !== this) return def.redefined() || def;
+        if (def && def !== self) return def.redefined() || def;
     },
     unmangleable: function(options) {
         return this.global && !options.toplevel
@@ -103,6 +104,15 @@ SymbolDef.prototype = {
     },
 };
 
+DEF_BITPROPS(SymbolDef, [
+    "const_redefs",
+    "cross_loop",
+    "direct_access",
+    "exported",
+    "global",
+    "undeclared",
+]);
+
 var unary_side_effects = makePredicate("delete ++ --");
 
 function is_lhs(node, parent) {
@@ -117,7 +127,7 @@ function is_lhs(node, parent) {
 AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
     options = defaults(options, {
         cache: null,
-        ie8: false,
+        ie: false,
     });
 
     // pass 1: setup scope chaining and handle definitions
@@ -210,7 +220,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             entangle(defun, scope);
         } else if (node instanceof AST_SymbolLambda) {
             var def = defun.def_function(node, node.name == "arguments" ? undefined : defun);
-            if (options.ie8) def.defun = defun.parent_scope.resolve();
+            if (options.ie) def.defun = defun.parent_scope.resolve();
         } else if (node instanceof AST_SymbolLet) {
             var def = scope.def_variable(node);
             if (exported) def.exported = true;
@@ -350,7 +360,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
     self.walk(tw);
 
     // pass 3: fix up any scoping issue with IE8
-    if (options.ie8) self.walk(new TreeWalker(function(node) {
+    if (options.ie) self.walk(new TreeWalker(function(node) {
         if (node instanceof AST_SymbolCatch) {
             var scope = node.thedef.defun;
             if (scope.name instanceof AST_SymbolLambda && scope.name.name == node.name) {
@@ -362,7 +372,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         if (node instanceof AST_SymbolLambda) {
             var def = node.thedef;
             if (!redefine(node, node.scope.parent_scope.resolve())) {
-                delete def.defun;
+                def.defun = undefined;
             } else if (typeof node.thedef.init !== "undefined") {
                 node.thedef.init = false;
             } else if (def.init) {
@@ -396,13 +406,14 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         } else {
             new_def = scope.def_variable(node);
         }
+        if (new_def.undeclared) self.variables.set(name, new_def);
+        if (name == "arguments" && is_arguments(old_def) && node instanceof AST_SymbolLambda) return true;
         old_def.defun = new_def.scope;
         old_def.forEach(function(node) {
             node.redef = old_def;
             node.thedef = new_def;
             node.reference(options);
         });
-        if (new_def.undeclared) self.variables.set(name, new_def);
         return true;
     }
 });
@@ -463,7 +474,7 @@ AST_Symbol.DEFMETHOD("mark_enclosed", function(options) {
     for (var s = this.scope; s; s = s.parent_scope) {
         push_uniq(s.enclosed, def);
         if (!options) {
-            delete s._var_names;
+            s._var_names = undefined;
         } else if (options.keep_fnames) {
             s.functions.each(function(d) {
                 push_uniq(def.scope.enclosed, d);
@@ -508,12 +519,12 @@ function names_in_use(scope, options) {
     if (!names) {
         scope.cname = -1;
         scope.cname_holes = [];
-        scope.names_in_use = names = Object.create(null);
+        scope.names_in_use = names = new Dictionary();
         var cache = options.cache && options.cache.props;
         scope.enclosed.forEach(function(def) {
-            if (def.unmangleable(options)) names[def.name] = true;
+            if (def.unmangleable(options)) names.set(def.name, true);
             if (def.global && cache && cache.has(def.name)) {
-                names[cache.get(def.name)] = true;
+                names.set(cache.get(def.name), true);
             }
         });
     }
@@ -524,34 +535,33 @@ function next_mangled_name(def, options) {
     var scope = def.scope;
     var in_use = names_in_use(scope, options);
     var holes = scope.cname_holes;
-    var names = Object.create(null);
+    var names = new Dictionary();
     var scopes = [ scope ];
     def.forEach(function(sym) {
         var scope = sym.scope;
         do {
-            if (scopes.indexOf(scope) < 0) {
+            if (member(scope, scopes)) break;
-                for (var name in names_in_use(scope, options)) {
+            names_in_use(scope, options).each(function(marker, name) {
-                    names[name] = true;
+                names.set(name, marker);
-                }
+            });
-                scopes.push(scope);
+            scopes.push(scope);
-            } else break;
         } while (scope = scope.parent_scope);
     });
     var name;
     for (var i = 0; i < holes.length; i++) {
         name = base54(holes[i]);
-        if (names[name]) continue;
+        if (names.has(name)) continue;
         holes.splice(i, 1);
-        in_use[name] = true;
+        in_use.set(name, true);
         return name;
     }
     while (true) {
         name = base54(++scope.cname);
-        if (in_use[name] || RESERVED_WORDS[name] || options.reserved.has[name]) continue;
+        if (in_use.has(name) || RESERVED_WORDS[name] || options.reserved.has[name]) continue;
-        if (!names[name]) break;
+        if (!names.has(name)) break;
         holes.push(scope.cname);
     }
-    in_use[name] = true;
+    in_use.set(name, true);
     return name;
 }
 
@@ -570,7 +580,7 @@ AST_Symbol.DEFMETHOD("definition", function() {
 function _default_mangler_options(options) {
     options = defaults(options, {
         eval        : false,
-        ie8         : false,
+        ie          : false,
         keep_fnames : false,
         reserved    : [],
         toplevel    : false,
@@ -596,7 +606,7 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
     if (options.cache && options.cache.props) {
         var mangled_names = names_in_use(this, options);
         options.cache.props.each(function(mangled_name) {
-            mangled_names[mangled_name] = true;
+            mangled_names.set(mangled_name, true);
         });
     }
 
@@ -800,6 +810,7 @@ var base54 = (function() {
     var leading = init("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_");
     var chars, frequency;
     function reset() {
+        chars = null;
         frequency = Object.create(freq);
     }
     base54.consider = function(str, delta) {
@@ -811,19 +822,15 @@ var base54 = (function() {
         return frequency[b] - frequency[a];
     }
     base54.sort = function() {
-        chars = leading.sort(compare).concat(digits.sort(compare));
+        chars = leading.sort(compare).concat(digits).sort(compare);
     };
     base54.reset = reset;
     reset();
     function base54(num) {
-        var ret = "", base = 54;
+        var ret = leading[num % 54];
-        num++;
+        for (num = Math.floor(num / 54); --num >= 0; num >>= 6) {
-        do {
+            ret += chars[num & 0x3F];
-            num--;
+        }
-            ret += chars[num % base];
-            num = Math.floor(num / base);
-            base = 64;
-        } while (num > 0);
         return ret;
     }
     return base54;

lib/sourcemap.js

@@ -77,21 +77,23 @@ function vlq_encode(num) {
 }
 
 function create_array_map() {
-    var map = Object.create(null);
+    var map = new Dictionary();
     var array = [];
     array.index = function(name) {
-        if (!HOP(map, name)) {
+        var index = map.get(name);
-            map[name] = array.length;
+        if (!(index >= 0)) {
+            index = array.length;
             array.push(name);
+            map.set(name, index);
         }
-        return map[name];
+        return index;
     };
     return array;
 }
 
 function SourceMap(options) {
     var sources = create_array_map();
-    var sources_content = options.includeSources && Object.create(null);
+    var sources_content = options.includeSources && new Dictionary();
     var names = create_array_map();
     var mappings = "";
     if (options.orig) Object.keys(options.orig).forEach(function(name) {
@@ -110,7 +112,7 @@ function SourceMap(options) {
         if (!sources_content || !map.sourcesContent) return;
         for (var i = 0; i < map.sources.length; i++) {
             var content = map.sourcesContent[i];
-            if (content) sources_content[map.sources[i]] = content;
+            if (content) sources_content.set(map.sources[i], content);
         }
     });
     var prev_source;
@@ -144,8 +146,8 @@ function SourceMap(options) {
             add(source, gen_line, gen_col, orig_line, orig_col, name);
         } : add,
         setSourceContent: sources_content ? function(source, content) {
-            if (!(source in sources_content)) {
+            if (!sources_content.has(source)) {
-                sources_content[source] = content;
+                sources_content.set(source, content);
             }
         } : noop,
         toString: function() {
@@ -155,7 +157,7 @@ function SourceMap(options) {
                 sourceRoot: options.root || undefined,
                 sources: sources,
                 sourcesContent: sources_content ? sources.map(function(source) {
-                    return sources_content[source] || null;
+                    return sources_content.get(source) || null;
                 }) : undefined,
                 names: names,
                 mappings: mappings,

lib/utils.js

@@ -96,15 +96,6 @@ function defaults(args, defs, croak) {
     return defs;
 }
 
-function merge(obj, ext) {
-    var count = 0;
-    for (var i in ext) if (HOP(ext, i)) {
-        obj[i] = ext[i];
-        count++;
-    }
-    return count;
-}
-
 function noop() {}
 function return_false() { return false; }
 function return_true() { return true; }
@@ -143,7 +134,7 @@ function push_uniq(array, el) {
 }
 
 function string_template(text, props) {
-    return text.replace(/\{([^}]+)\}/g, function(str, p) {
+    return text.replace(/\{([^{}]+)\}/g, function(str, p) {
         var value = props[p];
         return value instanceof AST_Node ? value.print_to_string() : value;
     });
@@ -171,63 +162,80 @@ function all(array, predicate) {
 }
 
 function Dictionary() {
-    this._values = Object.create(null);
+    this.values = Object.create(null);
-    this._size = 0;
 }
 Dictionary.prototype = {
     set: function(key, val) {
-        if (!this.has(key)) ++this._size;
+        if (key == "__proto__") {
-        this._values["$" + key] = val;
+            this.proto_value = val;
+        } else {
+            this.values[key] = val;
+        }
         return this;
     },
     add: function(key, val) {
-        if (this.has(key)) {
+        var list = this.get(key);
-            this.get(key).push(val);
+        if (list) {
+            list.push(val);
         } else {
             this.set(key, [ val ]);
         }
         return this;
     },
-    get: function(key) { return this._values["$" + key] },
+    get: function(key) {
+        return key == "__proto__" ? this.proto_value : this.values[key];
+    },
     del: function(key) {
-        if (this.has(key)) {
+        if (key == "__proto__") {
-            --this._size;
+            delete this.proto_value;
-            delete this._values["$" + key];
+        } else {
+            delete this.values[key];
         }
         return this;
     },
-    has: function(key) { return ("$" + key) in this._values },
+    has: function(key) {
+        return key == "__proto__" ? "proto_value" in this : key in this.values;
+    },
     all: function(predicate) {
-        for (var i in this._values)
+        for (var i in this.values)
-            if (!predicate(this._values[i], i.substr(1)))
+            if (!predicate(this.values[i], i)) return false;
-                return false;
+        if ("proto_value" in this && !predicate(this.proto_value, "__proto__")) return false;
         return true;
     },
     each: function(f) {
-        for (var i in this._values)
+        for (var i in this.values)
-            f(this._values[i], i.substr(1));
+            f(this.values[i], i);
+        if ("proto_value" in this) f(this.proto_value, "__proto__");
     },
     size: function() {
-        return this._size;
+        return Object.keys(this.values).length + ("proto_value" in this);
     },
     map: function(f) {
         var ret = [];
-        for (var i in this._values)
+        for (var i in this.values)
-            ret.push(f(this._values[i], i.substr(1)));
+            ret.push(f(this.values[i], i));
+        if ("proto_value" in this) ret.push(f(this.proto_value, "__proto__"));
         return ret;
     },
     clone: function() {
         var ret = new Dictionary();
-        for (var i in this._values)
+        this.each(function(value, i) {
-            ret._values[i] = this._values[i];
+            ret.set(i, value);
-        ret._size = this._size;
+        });
         return ret;
     },
-    toObject: function() { return this._values }
+    toObject: function() {
+        var obj = {};
+        this.each(function(value, i) {
+            obj["$" + i] = value;
+        });
+        return obj;
+    },
 };
 Dictionary.fromObject = function(obj) {
     var dict = new Dictionary();
-    dict._size = merge(dict._values, obj);
+    for (var i in obj)
+        if (HOP(obj, i)) dict.set(i.slice(1), obj[i]);
     return dict;
 };
 
@@ -265,3 +273,21 @@ function first_in_statement(stack, arrow, export_default) {
         return false;
     }
 }
+
+function DEF_BITPROPS(ctor, props) {
+    if (props.length > 31) throw new Error("Too many properties: " + props.length + "\n" + props.join(", "));
+    props.forEach(function(name, pos) {
+        var mask = 1 << pos;
+        Object.defineProperty(ctor.prototype, name, {
+            get: function() {
+                return !!(this._bits & mask);
+            },
+            set: function(val) {
+                if (val)
+                    this._bits |= mask;
+                else
+                    this._bits &= ~mask;
+            },
+        });
+    });
+}

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": "3.13.6",
+  "version": "3.14.5",
   "engines": {
     "node": ">=0.8.0"
   },

test/benchmark.js

@@ -16,7 +16,7 @@ var urls = [
     "https://code.angularjs.org/1.7.8/angular.js",
     "https://unpkg.com/mathjs@6.2.3/dist/math.js",
     "https://unpkg.com/react@15.3.2/dist/react.js",
-    "https://cdnjs.cloudflare.com/ajax/libs/d3/5.12.0/d3.js",
+    "https://cdnjs.cloudflare.com/ajax/libs/d3/6.7.0/d3.js",
     "https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.js",
     "https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.js",
     "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.12.2/ember.prod.js",

test/compress/annotations.js

@@ -256,6 +256,7 @@ issue_3858: {
         collapse_vars: true,
         inline: true,
         keep_fargs: false,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -441,9 +442,9 @@ compress_annotations_disabled_output_annotations_enabled: {
     }
     expect_exact: [
         "/*@__PURE__*/a(3),",
-        "/*#__PURE__*/b(5),",
+        "/*@__PURE__*/b(5),",
         "c(side_effect),",
-        "/*#__PURE__*/d(effect());",
+        "/*@__PURE__*/d(effect());",
     ]
 }
 

test/compress/arguments.js

@@ -254,6 +254,25 @@ duplicate_argname: {
     expect_stdout: "bar 42 foo 42 bar"
 }
 
+fraction: {
+    options = {
+        arguments: true,
+        keep_fargs: false,
+        reduce_vars: true,
+    }
+    input: {
+        console.log(function() {
+            return arguments[0.3];
+        }("FAIL") || "PASS");
+    }
+    expect: {
+        console.log(function() {
+            return arguments[0.3];
+        }("FAIL") || "PASS");
+    }
+    expect_stdout: "PASS"
+}
+
 issue_3273: {
     options = {
         arguments: true,

test/compress/arrows.js

@@ -363,6 +363,28 @@ negate: {
 }
 
 inline_this: {
+    options = {
+        inline: true,
+    }
+    input: {
+        var p = "PASS";
+        console.log({
+            p: "FAIL",
+            q: (() => this.p)(),
+        }.q);
+    }
+    expect: {
+        var p = "PASS";
+        console.log({
+            p: "FAIL",
+            q: this.p,
+        }.q);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+dont_inline_this: {
     options = {
         inline: true,
     }
@@ -421,6 +443,7 @@ collapse_value: {
         arrows: true,
         collapse_vars: true,
         keep_fargs: false,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -555,6 +578,75 @@ reduce_iife_3: {
     node_version: ">=4"
 }
 
+reduce_lambda_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f = () => {
+            console.log(a, b);
+        };
+        var a = "foo", b = 42;
+        f();
+        b = "bar";
+        f();
+    }
+    expect: {
+        var f = () => {
+            console.log("foo", b);
+        };
+        var b = 42;
+        f();
+        b = "bar";
+        f();
+    }
+    expect_stdout: [
+        "foo 42",
+        "foo bar",
+    ]
+    node_version: ">=4"
+}
+
+reduce_lambda_2: {
+    options = {
+        evaluate: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function(f, a, b) {
+            f = () => {
+                console.log(a, b);
+            };
+            a = "foo", b = 42;
+            f();
+            b = "bar";
+            f();
+        })();
+    }
+    expect: {
+        (function(f, a, b) {
+            f = () => {
+                console.log("foo", b);
+            };
+            b = 42;
+            f();
+            b = "bar";
+            f();
+        })();
+    }
+    expect_stdout: [
+        "foo 42",
+        "foo bar",
+    ]
+    node_version: ">=4"
+}
+
 single_use_recursive: {
     options = {
         reduce_vars: true,

test/compress/assignments.js

@@ -550,6 +550,24 @@ logical_side_effects: {
     node_version: ">=15"
 }
 
+evaluate_lazy_assignment: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 42;
+        console.log(a &&= "PASS");
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
 issue_4815_1: {
     options = {
         evaluate: true,
@@ -701,3 +719,48 @@ issue_4876: {
     expect_stdout: "PASS"
     node_version: ">=15"
 }
+
+issue_4924_1: {
+    options = {
+        collapse_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b;
+        console.log("PASS");
+        a = function() {};
+        b = function() {}(b ||= a);
+    }
+    expect: {
+        var b;
+        console.log("PASS");
+        b = void (b ||= function() {});
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+issue_4924_2: {
+    options = {
+        collapse_vars: true,
+        dead_code: true,
+        passes: 2,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b;
+        console.log("PASS");
+        a = function() {};
+        b = function() {}(b ||= a);
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}

test/compress/awaits.js

@@ -227,9 +227,7 @@ inline_await_1_trim: {
         console.log("PASS");
     }
     expect: {
-        (async function() {
+        0;
-            await 0;
-        })();
         console.log("PASS");
     }
     expect_stdout: "PASS"
@@ -334,7 +332,7 @@ inline_await_3_trim: {
     }
     expect: {
         (async function() {
-            return a = "PASS", b = console.log, await b(a);
+            return a = "PASS", b = console.log, b(a);
             var a, b;
         })();
     }
@@ -342,6 +340,33 @@ inline_await_3_trim: {
     node_version: ">=8"
 }
 
+inline_await_this: {
+    options = {
+        awaits: true,
+        inline: true,
+    }
+    input: {
+        var p = "FAIL";
+        ({
+            p: "PASS",
+            async f() {
+                return await (async () => this.p)();
+            },
+        }).f().then(console.log);
+    }
+    expect: {
+        var p = "FAIL";
+        ({
+            p: "PASS",
+            async f() {
+                return await this.p;
+            },
+        }).f().then(console.log);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
 await_unary: {
     options = {
         awaits: true,
@@ -455,7 +480,7 @@ object_function: {
         }).f();
     }
     expect: {
-        (async function() {
+        (async () => {
             console.log("PASS");
         })();
     }
@@ -557,6 +582,51 @@ collapse_property_lambda: {
     node_version: ">=8"
 }
 
+drop_async_1: {
+    options = {
+        awaits: true,
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(function(a) {
+            (async function() {
+                a *= 7;
+            })();
+            return a;
+        }(6));
+    }
+    expect: {
+        console.log(function(a) {
+            a *= 7;
+            return a;
+        }(6));
+    }
+    expect_stdout: "42"
+    node_version: ">=8"
+}
+
+drop_async_2: {
+    options = {
+        awaits: true,
+        collapse_vars: true,
+        evaluate: true,
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(function(a) {
+            (async b => await (a *= b))(7);
+            return a;
+        }(6));
+    }
+    expect: {
+        console.log(42);
+    }
+    expect_stdout: "42"
+    node_version: ">=8"
+}
+
 drop_return: {
     options = {
         side_effects: true,
@@ -1531,3 +1601,667 @@ issue_4764_3: {
     expect_stdout: "PASS"
     node_version: ">=8"
 }
+
+issue_4972_1: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            try {
+                return await "bar";
+            } finally {
+                console.log("baz");
+            }
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            try {
+                return await "bar";
+            } finally {
+                console.log("baz");
+            }
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "moo",
+        "baz",
+        "bar",
+    ]
+    node_version: ">=8"
+}
+
+issue_4972_2: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            try {
+                console.log("bar");
+            } finally {
+                return await "baz";
+            }
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            try {
+                console.log("bar");
+            } finally {
+                return "baz";
+            }
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+        "baz",
+    ]
+    node_version: ">=8"
+}
+
+issue_4972_3: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        try {
+            (async function() {
+                return await "bar";
+            })().then(console.log);
+        } finally {
+            console.log("baz");
+        }
+        console.log("moo");
+    }
+    expect: {
+        console.log("foo");
+        try {
+            (async function() {
+                return "bar";
+            })().then(console.log);
+        } finally {
+            console.log("baz");
+        }
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "baz",
+        "moo",
+        "bar",
+    ]
+    node_version: ">=8"
+}
+
+issue_4974: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function f() {
+            return 42 in f();
+        })();
+        console.log("PASS");
+    }
+    expect: {
+        (async function f() {
+            return 42 in f();
+        })();
+        console.log("PASS");
+    }
+    expect_stdout: true
+    node_version: ">=8"
+}
+
+issue_4975: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function f(a) {
+            try {
+                if (a) console.log(typeof f());
+            } catch (e) {}
+        })(42);
+    }
+    expect: {
+        (async function f(a) {
+            try {
+                if (a) console.log(typeof f());
+            } catch (e) {}
+        })(42);
+    }
+    expect_stdout: "object"
+    node_version: ">=8"
+}
+
+issue_4987: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                await 42;
+            } finally {
+                console.log("foo");
+            }
+        })();
+        console.log("bar");
+    }
+    expect: {
+        (async function() {
+            try {
+                await 0;
+            } finally {
+                console.log("foo");
+            }
+        })();
+        console.log("bar");
+    }
+    expect_stdout: [
+        "bar",
+        "foo",
+    ]
+    node_version: ">=8"
+}
+
+issue_5001: {
+    options = {
+        awaits: true,
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 0;
+        (async function() {
+            a++ | await 42;
+        })();
+        console.log(a ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = 0;
+        a++;
+        console.log(a ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5019_1: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        (function(a) {
+            (async function() {
+                await 42;
+                console.log(a);
+            })();
+            a = "PASS";
+        })("FAIL");
+    }
+    expect: {
+        (function(a) {
+            (async function() {
+                await 42;
+                console.log(a);
+            })();
+            a = "PASS";
+        })("FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5019_2: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        console.log("sync", function(a) {
+            (async function() {
+                console.log(await "async", a);
+            })();
+            return a = "PASS";
+        }("FAIL"));
+    }
+    expect: {
+        console.log("sync", function(a) {
+            (async function() {
+                console.log(await "async", a);
+            })();
+            return a = "PASS";
+        }("FAIL"));
+    }
+    expect_stdout: [
+        "sync PASS",
+        "async PASS",
+    ]
+    node_version: ">=8"
+}
+
+issue_5019_3: {
+    options = {
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        for (var i in "foo") {
+            (function(a) {
+                (async function() {
+                    console.log(await "async", a);
+                })();
+            })(i);
+            console.log("sync", i);
+        }
+    }
+    expect: {
+        for (var i in "foo") {
+            (function(a) {
+                (async function() {
+                    console.log(await "async", a);
+                })();
+            })(i);
+            console.log("sync", i);
+        }
+    }
+    expect_stdout: [
+        "sync 0",
+        "sync 1",
+        "sync 2",
+        "async 0",
+        "async 1",
+        "async 2",
+    ]
+    node_version: ">=8"
+}
+
+issue_5023_1: {
+    options = {
+        awaits: true,
+        reduce_vars: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            let a = a;
+        })();
+        console.log("PASS");
+    }
+    expect: {
+        (async function() {
+            let a = a;
+        })();
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5023_2: {
+    options = {
+        awaits: true,
+        reduce_vars: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            let a;
+            a = a;
+        })();
+        console.log("PASS");
+    }
+    expect: {
+        (function() {
+            let a;
+            a = a;
+        })();
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5032_normal: {
+    options = {
+        merge_vars: true,
+        webkit: false,
+    }
+    input: {
+        function log(value) {
+            console.log(value);
+            return value;
+        }
+        async function f(a) {
+            var b = log(a), c = b;
+            log(b);
+            log(c);
+        }
+        f("PASS");
+    }
+    expect: {
+        function log(value) {
+            console.log(value);
+            return value;
+        }
+        async function f(c) {
+            var b = log(c), c = b;
+            log(b);
+            log(c);
+        }
+        f("PASS");
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+        "PASS",
+    ]
+    node_version: ">=8"
+}
+
+issue_5032_webkit: {
+    options = {
+        merge_vars: true,
+        webkit: true,
+    }
+    input: {
+        function log(value) {
+            console.log(value);
+            return value;
+        }
+        async function f(a) {
+            var b = log(a), c = b;
+            log(b);
+            log(c);
+        }
+        f("PASS");
+    }
+    expect: {
+        function log(value) {
+            console.log(value);
+            return value;
+        }
+        async function f(a) {
+            var b = log(a), c = b;
+            log(b);
+            log(c);
+        }
+        f("PASS");
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+        "PASS",
+    ]
+    node_version: ">=8"
+}
+
+issue_5034: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var await = function f() {
+                return async function() {
+                    return f;
+                };
+            };
+            await()().then(function(value) {
+                console.log(value === await ? "PASS" : "FAIL");
+            });
+        })();
+    }
+    expect: {
+        (function() {
+            var await = function f() {
+                return async function() {
+                    return f;
+                };
+            };
+            await()().then(function(value) {
+                console.log(value === await ? "PASS" : "FAIL");
+            });
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5070: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                for await (var a of console.log("PASS"));
+            } catch (e) {}
+        })();
+    }
+    expect: {
+        (async function() {
+            try {
+                for await (var a of console.log("PASS"));
+            } catch (e) {}
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=10"
+}
+
+issue_5157_async_function: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        async function f() {
+            throw "FAIL";
+        }
+        (async function() {
+            try {
+                return await f();
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect: {
+        async function f() {
+            throw "FAIL";
+        }
+        (async function() {
+            try {
+                return await f();
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5157_async_iife: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                return await async function() {
+                    throw "FAIL";
+                }();
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect: {
+        (async function() {
+            try {
+                return await async function() {
+                    throw "FAIL";
+                }();
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5157_promise: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        var p = new Promise(function(resolve, reject) {
+            reject("FAIL");
+        });
+        (async function() {
+            try {
+                return await p;
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect: {
+        var p = new Promise(function(resolve, reject) {
+            reject("FAIL");
+        });
+        (async function() {
+            try {
+                return await p;
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5159_1: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                throw "foo";
+            } catch (e) {
+                return await "bar";
+            } finally {
+                console.log("baz");
+            }
+        })().catch(console.log).then(console.log);
+        console.log("moo");
+    }
+    expect: {
+        (async function() {
+            try {
+                throw "foo";
+            } catch (e) {
+                return await "bar";
+            } finally {
+                console.log("baz");
+            }
+        })().catch(console.log).then(console.log);
+        console.log("moo");
+    }
+    expect_stdout: [
+        "moo",
+        "baz",
+        "bar",
+    ]
+    node_version: ">=8"
+}
+
+issue_5159_2: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                throw "foo";
+            } catch (e) {
+                return await "bar";
+            }
+        })().catch(console.log).then(console.log);
+        console.log("baz");
+    }
+    expect: {
+        (async function() {
+            try {
+                throw "foo";
+            } catch (e) {
+                return "bar";
+            }
+        })().catch(console.log).then(console.log);
+        console.log("baz");
+    }
+    expect_stdout: [
+        "baz",
+        "bar",
+    ]
+    node_version: ">=8"
+}
+
+issue_5177: {
+    options = {
+        properties: true,
+    }
+    input: {
+        (async function() {
+            return {
+                p(await) {},
+            }.p;
+        })().then(function(a) {
+            console.log(typeof a);
+        });
+    }
+    expect: {
+        (async function() {
+            return {
+                p(await) {},
+            }.p;
+        })().then(function(a) {
+            console.log(typeof a);
+        });
+    }
+    expect_stdout: "function"
+    node_version: ">=8"
+}

test/compress/bigint.js

@@ -4,7 +4,7 @@ arithmetic: {
     }
     expect_exact: "console.log((1n+0x2n)*(0o3n- -4n)>>5n-6n);"
     expect_stdout: "42n"
-    node_version: ">=10"
+    node_version: ">=10.4.0"
 }
 
 minus_dot: {
@@ -13,7 +13,7 @@ minus_dot: {
     }
     expect_exact: "console.log(typeof-42n.toString(),typeof(-42n).toString());"
     expect_stdout: "number string"
-    node_version: ">=10"
+    node_version: ">=10.4.0"
 }
 
 evaluate: {
@@ -28,7 +28,7 @@ evaluate: {
         console.log(0xdeadbeefn.toString(16));
     }
     expect_stdout: "deadbeef"
-    node_version: ">=10"
+    node_version: ">=10.4.0"
 }
 
 Number: {
@@ -42,7 +42,7 @@ Number: {
         console.log(+("" + -0xfeed_dead_beef_badn));
     }
     expect_stdout: "-1148098955808013200"
-    node_version: ">=10"
+    node_version: ">=10.4.0"
 }
 
 issue_4590: {
@@ -58,7 +58,7 @@ issue_4590: {
         0n || console.log("PASS");
     }
     expect_stdout: "PASS"
-    node_version: ">=10"
+    node_version: ">=10.4.0"
 }
 
 issue_4801: {
@@ -88,5 +88,5 @@ issue_4801: {
         }
     }
     expect_stdout: "PASS"
-    node_version: ">=10"
+    node_version: ">=10.4.0"
 }

test/compress/booleans.js

@@ -29,6 +29,404 @@ iife_boolean_context: {
     ]
 }
 
+de_morgan_1a: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        function f(a) {
+            return a || a;
+        }
+        console.log(f(null), f(42));
+    }
+    expect: {
+        function f(a) {
+            return a;
+        }
+        console.log(f(null), f(42));
+    }
+    expect_stdout: "null 42"
+}
+
+de_morgan_1b: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        function f(a) {
+            return a && a;
+        }
+        console.log(f(null), f(42));
+    }
+    expect: {
+        function f(a) {
+            return a;
+        }
+        console.log(f(null), f(42));
+    }
+    expect_stdout: "null 42"
+}
+
+de_morgan_1c: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        console.log(delete (NaN && NaN));
+    }
+    expect: {
+        console.log(delete (0, NaN));
+    }
+    expect_stdout: "true"
+}
+
+de_morgan_2a: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        function f(a, b) {
+            return a || (a || b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a || b;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "undefined {}",
+        "42 42",
+    ]
+}
+
+de_morgan_2b: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        function f(a, b) {
+            return a || (a && b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "null null",
+        "42 42",
+    ]
+}
+
+de_morgan_2c: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        function f(a, b) {
+            return a && (a || b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "null null",
+        "42 42",
+    ]
+}
+
+de_morgan_2d: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        side_effects: true,
+    }
+    input: {
+        function f(a, b) {
+            return a && (a && b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a && b;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "null null",
+        "undefined {}",
+    ]
+}
+
+de_morgan_3a: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        function f(a, b, c) {
+            return a || ((a || b) || c);
+        }
+        console.log(f(null, false), f(null, false, {}), f(null, true), f(null, true, {}));
+        console.log(f(42, false), f(42, false, {}), f(42, true), f(42, true, {}));
+    }
+    expect: {
+        function f(a, b, c) {
+            return a || b || c;
+        }
+        console.log(f(null, !1), f(null, !1, {}), f(null, !0), f(null, !0, {}));
+        console.log(f(42, !1), f(42, !1, {}), f(42, !0), f(42, !0, {}));
+    }
+    expect_stdout: [
+        "undefined {} true true",
+        "42 42 42 42",
+    ]
+}
+
+de_morgan_3b: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        side_effects: true,
+    }
+    input: {
+        function f(a, b, c) {
+            return a || ((a || b) && c);
+        }
+        console.log(f(null, false), f(null, false, {}), f(null, true), f(null, true, {}));
+        console.log(f(42, false), f(42, false, {}), f(42, true), f(42, true, {}));
+    }
+    expect: {
+        function f(a, b, c) {
+            return a || b && c;
+        }
+        console.log(f(null, !1), f(null, !1, {}), f(null, !0), f(null, !0, {}));
+        console.log(f(42, !1), f(42, !1, {}), f(42, !0), f(42, !0, {}));
+    }
+    expect_stdout: [
+        "false false undefined {}",
+        "42 42 42 42",
+    ]
+}
+
+de_morgan_3c: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        side_effects: true,
+    }
+    input: {
+        function f(a, b, c) {
+            return a || ((a && b) || c);
+        }
+        console.log(f(null, false), f(null, false, {}), f(null, true), f(null, true, {}));
+        console.log(f(42, false), f(42, false, {}), f(42, true), f(42, true, {}));
+    }
+    expect: {
+        function f(a, b, c) {
+            return a || c;
+        }
+        console.log(f(null, !1), f(null, !1, {}), f(null, !0), f(null, !0, {}));
+        console.log(f(42, !1), f(42, !1, {}), f(42, !0), f(42, !0, {}));
+    }
+    expect_stdout: [
+        "undefined {} undefined {}",
+        "42 42 42 42",
+    ]
+}
+
+de_morgan_3d: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        function f(a, b, c) {
+            return a || ((a && b) && c);
+        }
+        console.log(f(null, false), f(null, false, {}), f(null, true), f(null, true, {}));
+        console.log(f(42, false), f(42, false, {}), f(42, true), f(42, true, {}));
+    }
+    expect: {
+        function f(a, b, c) {
+            return a;
+        }
+        console.log(f(null, !1), f(null, !1, {}), f(null, !0), f(null, !0, {}));
+        console.log(f(42, !1), f(42, !1, {}), f(42, !0), f(42, !0, {}));
+    }
+    expect_stdout: [
+        "null null null null",
+        "42 42 42 42",
+    ]
+}
+
+de_morgan_3e: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        function f(a, b, c) {
+            return a && ((a || b) || c);
+        }
+        console.log(f(null, false), f(null, false, {}), f(null, true), f(null, true, {}));
+        console.log(f(42, false), f(42, false, {}), f(42, true), f(42, true, {}));
+    }
+    expect: {
+        function f(a, b, c) {
+            return a;
+        }
+        console.log(f(null, !1), f(null, !1, {}), f(null, !0), f(null, !0, {}));
+        console.log(f(42, !1), f(42, !1, {}), f(42, !0), f(42, !0, {}));
+    }
+    expect_stdout: [
+        "null null null null",
+        "42 42 42 42",
+    ]
+}
+
+de_morgan_3f: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        side_effects: true,
+    }
+    input: {
+        function f(a, b, c) {
+            return a && ((a || b) && c);
+        }
+        console.log(f(null, false), f(null, false, {}), f(null, true), f(null, true, {}));
+        console.log(f(42, false), f(42, false, {}), f(42, true), f(42, true, {}));
+    }
+    expect: {
+        function f(a, b, c) {
+            return a && c;
+        }
+        console.log(f(null, !1), f(null, !1, {}), f(null, !0), f(null, !0, {}));
+        console.log(f(42, !1), f(42, !1, {}), f(42, !0), f(42, !0, {}));
+    }
+    expect_stdout: [
+        "null null null null",
+        "undefined {} undefined {}",
+    ]
+}
+
+de_morgan_3g: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        side_effects: true,
+    }
+    input: {
+        function f(a, b, c) {
+            return a && ((a && b) || c);
+        }
+        console.log(f(null, false), f(null, false, {}), f(null, true), f(null, true, {}));
+        console.log(f(42, false), f(42, false, {}), f(42, true), f(42, true, {}));
+    }
+    expect: {
+        function f(a, b, c) {
+            return a && (b || c);
+        }
+        console.log(f(null, !1), f(null, !1, {}), f(null, !0), f(null, !0, {}));
+        console.log(f(42, !1), f(42, !1, {}), f(42, !0), f(42, !0, {}));
+    }
+    expect_stdout: [
+        "null null null null",
+        "undefined {} true true",
+    ]
+}
+
+de_morgan_3h: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        function f(a, b, c) {
+            return a && ((a && b) && c);
+        }
+        console.log(f(null, false), f(null, false, {}), f(null, true), f(null, true, {}));
+        console.log(f(42, false), f(42, false, {}), f(42, true), f(42, true, {}));
+    }
+    expect: {
+        function f(a, b, c) {
+            return a && b && c;
+        }
+        console.log(f(null, !1), f(null, !1, {}), f(null, !0), f(null, !0, {}));
+        console.log(f(42, !1), f(42, !1, {}), f(42, !0), f(42, !0, {}));
+    }
+    expect_stdout: [
+        "null null null null",
+        "false false undefined {}",
+    ]
+}
+
+conditional_chain: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        evaluate: true,
+    }
+    input: {
+        function f(a, b) {
+            return a ? a : b ? b : 42;
+        }
+        console.log(f("PASS", "FAIL"));
+    }
+    expect: {
+        function f(a, b) {
+            return a || b || 42;
+        }
+        console.log(f("PASS", "FAIL"));
+    }
+    expect_stdout: "PASS"
+}
+
+negated_if: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(function(a) {
+            if (!a)
+                return a ? "FAIL" : "PASS";
+        }(!console));
+    }
+    expect: {
+        console.log(function(a) {
+            if (!a)
+                return "PASS";
+        }(!console));
+    }
+    expect_stdout: "PASS"
+}
+
 issue_3465_1: {
     options = {
         booleans: true,
@@ -181,3 +579,121 @@ issue_4374: {
     }
     expect_stdout: "0"
 }
+
+issue_5028_1: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        var a = 1;
+        console.log(function() {
+            return a-- ? a-- ? "FAIL 1" : "PASS" : "FAIL 2";
+        }());
+    }
+    expect: {
+        var a = 1;
+        console.log(function() {
+            return a-- ? a-- ? "FAIL 1" : "PASS" : "FAIL 2";
+        }());
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5028_2: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        dead_code: true,
+        if_return: true,
+    }
+    input: {
+        var a = 1;
+        (function() {
+            if (a--)
+                if (a--)
+                    a = "FAIL";
+                else
+                    return;
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = 1;
+        (function() {
+            a-- && a-- && (a = "FAIL");
+        })();
+        console.log(a);
+    }
+    expect_stdout: "-1"
+}
+
+issue_5028_3: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        evaluate: true,
+        if_return: true,
+    }
+    input: {
+        var a = 1;
+        (function() {
+            if (a--)
+                if (a--)
+                    a = "FAIL";
+                else
+                    return;
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = 1;
+        (function() {
+            a-- && a-- && (a = "FAIL");
+        })();
+        console.log(a);
+    }
+    expect_stdout: "-1"
+}
+
+issue_5041_1: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        var a = 42;
+        if (a)
+            if ([ a = null ])
+                if (a)
+                    console.log("FAIL");
+                else
+                    console.log("PASS");
+    }
+    expect: {
+        var a = 42;
+        a && [ a = null ] && (a ? console.log("FAIL") : console.log("PASS"));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5041_2: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        var a;
+        if (!a)
+            if (a = 42)
+                if (a)
+                    console.log("PASS");
+                else
+                    console.log("FAIL");
+    }
+    expect: {
+        var a;
+        a || (a = 42) && (a ? console.log("PASS") : console.log("FAIL"));
+    }
+    expect_stdout: "PASS"
+}

test/compress/classes.js

@@ -72,7 +72,7 @@ fields: {
             console.log(k, o[k]);
         console.log(o.q);
     }
-    expect_exact: 'var o=new class A{"#p";static #p="PASS";async;get q(){return A.#p}[6*7]=console?"foo":"bar"};for(var k in o)console.log(k,o[k]);console.log(o.q);'
+    expect_exact: 'var o=new class A{"#p";static#p="PASS";async;get q(){return A.#p}[6*7]=console?"foo":"bar"};for(var k in o)console.log(k,o[k]);console.log(o.q);'
     expect_stdout: [
         "42 foo",
         "#p undefined",
@@ -136,7 +136,7 @@ private_methods: {
             }
         }().q.then(console.log);
     }
-    expect_exact: "(new class A{static*#f(){yield 3*A.#p}async #g(){for(var a of A.#f())return a*await 2}static get #p(){return 7}get q(){return this.#g()}}).q.then(console.log);"
+    expect_exact: "(new class A{static*#f(){yield 3*A.#p}async#g(){for(var a of A.#f())return a*await 2}static get#p(){return 7}get q(){return this.#g()}}).q.then(console.log);"
     expect_stdout: "42"
     node_version: ">=14.6"
 }
@@ -260,6 +260,9 @@ block_scoped: {
     expect: {
         "use strict";
         0;
+        {
+            class A {}
+        }
         if (console) {
             class B {}
         }
@@ -269,6 +272,38 @@ block_scoped: {
     node_version: ">=4"
 }
 
+retain_declaration: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        "use strict";
+        var a = "FAIL";
+        try {
+            console.log(function() {
+                return a;
+                class a {}
+            }());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        var a = "FAIL";
+        try {
+            console.log(function() {
+                return a;
+                class a {}
+            }());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 drop_extends: {
     options = {
         inline: true,
@@ -632,6 +667,7 @@ collapse_non_strict: {
 collapse_rhs: {
     options = {
         collapse_vars: true,
+        unsafe: true,
     }
     input: {
         "use strict";
@@ -937,9 +973,9 @@ issue_4681: {
     }
     expect: {
         console.log(function(a) {
-            class A {
+            (class {
                 static p = a = this;
-            }
+            });
             return typeof a;
         }());
     }
@@ -1121,7 +1157,7 @@ issue_4705: {
 
 issue_4720: {
     options = {
-        ie8: true,
+        ie: true,
         reduce_vars: true,
         toplevel: true,
         unused: true,
@@ -1363,9 +1399,9 @@ issue_4821_1: {
     }
     expect: {
         var a;
-        class A {
+        (class {
             static p = void (a = this);
-        }
+        });
         console.log(typeof a);
     }
     expect_stdout: "function"
@@ -1563,3 +1599,501 @@ drop_unused_self_reference: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4951_1: {
+    input: {
+        class A {
+            static#p = console.log("PASS");
+        }
+    }
+    expect_exact: 'class A{static#p=console.log("PASS")}'
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_4951_2: {
+    input: {
+        new class {
+            constructor() {
+                this.#f().then(console.log);
+            }
+            async#f() {
+                return await "PASS";
+            }
+        }();
+    }
+    expect_exact: 'new class{constructor(){this.#f().then(console.log)}async#f(){return await"PASS"}};'
+    expect_stdout: "PASS"
+    node_version: ">=14.6"
+}
+
+issue_4962_1: {
+    options = {
+        ie: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            function f() {
+                while (console.log(typeof g));
+            }
+            class A {
+                static p = f();
+            }
+        })(function g() {});
+    }
+    expect: {
+        (function g() {}),
+        void function() {
+            while (console.log(typeof g));
+        }();
+    }
+    expect_stdout: "undefined"
+    node_version: ">=12"
+}
+
+issue_4962_2: {
+    options = {
+        ie: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function f() {}(function g() {
+            function h() {
+                f;
+            }
+            class A {
+                static p = h();
+            }
+        }, typeof g));
+    }
+    expect: {
+        console.log(function f() {}(function g() {
+            f;
+        }));
+    }
+    expect_stdout: "undefined"
+    node_version: ">=12"
+}
+
+issue_4982_1: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        "use strict";
+        try {} catch (e) {
+            class A extends 42 {}
+        }
+        console.log("PASS");
+    }
+    expect: {
+        "use strict";
+        {
+            class A {}
+        }
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4982_2: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = "PASS";
+        try {} catch (e) {
+            class A {
+                static p = a = "FAIL";
+            }
+        }
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        {
+            class A {}
+        }
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_4992: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        class A {
+            static P = this;
+            get p() {}
+        }
+        console.log(typeof A.P);
+    }
+    expect: {
+        console.log(typeof class {
+            static P = this;
+            get p() {}
+        }.P);
+    }
+    expect_stdout: "function"
+    node_version: ">=12"
+}
+
+issue_4996_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 1;
+        console.log(new class A {
+            p = a-- && new A();
+        }().p.p);
+    }
+    expect: {
+        var a = 1;
+        console.log(new class A {
+            p = a-- && new A();
+        }().p.p);
+    }
+    expect_stdout: "0"
+    node_version: ">=12"
+}
+
+issue_4996_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 1;
+        console.log(new class A {
+            p = a-- && new A();
+        }().p.p);
+    }
+    expect: {
+        var a = 1;
+        console.log(new class A {
+            p = a-- && new A();
+        }().p.p);
+    }
+    expect_stdout: "0"
+    node_version: ">=12"
+}
+
+issue_5015_1: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        "use strict";
+        var a;
+        try {
+            (class a {
+                [a]() {}
+            });
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        var a;
+        try {
+            (class a {
+                [a]() {}
+            });
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5015_2: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        try {
+            new class A {
+                [(A, 42)]() {}
+            }();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            new class A {
+                [(A, 42)]() {}
+            }();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5015_3: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        (class A {
+            static f() {
+                return A;
+            }
+        });
+        console.log("PASS");
+    }
+    expect: {
+        "use strict";
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5053_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        try {
+            console.log(new class A {
+                constructor() {
+                    A = 42;
+                }
+            }());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            console.log(new class A {
+                constructor() {
+                    A = 42;
+                }
+            }());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5053_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        try {
+            console.log(new class A {
+                f() {
+                    A = 42;
+                }
+            }().f());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            console.log(new class A {
+                f() {
+                    A = 42;
+                }
+            }().f());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5053_3: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        try {
+            console.log(new class A {
+                p = A = 42;
+            }().p);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            console.log(new class A {
+                p = A = 42;
+            }().p);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5053_4: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        class A {
+            constructor() {
+                A = 42;
+            }
+        }
+        try {
+            console.log(new A());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        class A {
+            constructor() {
+                A = 42;
+            }
+        }
+        try {
+            console.log(new A());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5082_1: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            class B {
+                static P = new A();
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            new A();
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5082_2: {
+    options = {
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            class B {
+                static P = new A();
+            }
+        })();
+    }
+    expect: {
+        void new class {
+            p = console.log("PASS");
+            q() {}
+        }();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5142: {
+    options = {
+        evaluate: true,
+        merge_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0, b;
+        if (++a)
+            new class {
+                p = b = null;
+                constructor(c) {
+                    console.log(c ? "FAIL" : "PASS");
+                }
+            }(b, a);
+    }
+    expect: {
+        var a = 0, b;
+        if (++a)
+            new class {
+                p = b = null;
+                constructor(c) {
+                    console.log(c ? "FAIL" : "PASS");
+                }
+            }(b, 1);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}

test/compress/collapse_vars.js

@@ -2264,6 +2264,7 @@ var_defs: {
         properties: true,
         sequences: true,
         side_effects: true,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -2486,6 +2487,7 @@ issue_1858: {
     options = {
         collapse_vars: true,
         pure_getters: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -2907,6 +2909,7 @@ compound_assignment_2: {
 issue_2187_1: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -4271,6 +4274,7 @@ issue_2436_14: {
     options = {
         collapse_vars: true,
         reduce_vars: true,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -4724,7 +4728,7 @@ cascade_statement: {
         }
         function f3(a, b) {
             for (; a < b; a++)
-                if (c = a, a && b)
+                if ((c = a) && b)
                     var c = c = b(a);
         }
     }
@@ -4761,6 +4765,7 @@ unsafe_builtin: {
     options = {
         collapse_vars: true,
         pure_getters: "strict",
+        reduce_vars: true,
         unsafe: true,
         unused: true,
     }
@@ -6003,7 +6008,7 @@ issue_3215_1: {
     options = {
         collapse_vars: true,
         evaluate: true,
-        ie8: false,
+        ie: false,
         inline: true,
         passes: 2,
         side_effects: true,
@@ -6025,7 +6030,7 @@ issue_3215_2: {
     options = {
         collapse_vars: true,
         evaluate: true,
-        ie8: true,
+        ie: true,
         inline: true,
         passes: 2,
         side_effects: true,
@@ -6050,7 +6055,7 @@ issue_3215_3: {
     options = {
         collapse_vars: true,
         evaluate: true,
-        ie8: false,
+        ie: false,
         inline: true,
         passes: 2,
         side_effects: true,
@@ -6073,7 +6078,7 @@ issue_3215_4: {
     options = {
         collapse_vars: true,
         evaluate: true,
-        ie8: true,
+        ie: true,
         inline: true,
         passes: 2,
         side_effects: true,
@@ -6965,6 +6970,7 @@ sequence_in_iife_2: {
         inline: true,
         passes: 2,
         side_effects: true,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -6976,7 +6982,7 @@ sequence_in_iife_2: {
     }
     expect: {
         var a = "foo", b = 42;
-        console.log(a, b = a);
+        console.log(b = a, b);
     }
     expect_stdout: "foo foo"
 }
@@ -6988,6 +6994,7 @@ sequence_in_iife_3: {
         passes: 2,
         side_effects: true,
         toplevel: true,
+        unsafe: true,
         unused: true,
     }
     input: {
@@ -7092,6 +7099,7 @@ setter_side_effect: {
 substitution_assign: {
     options = {
         collapse_vars: true,
+        unsafe: true,
     }
     input: {
         function f1(a, b) {
@@ -7112,8 +7120,7 @@ substitution_assign: {
     }
     expect: {
         function f1(a, b) {
-            f1 = a;
+            console.log(f1 = a, a);
-            console.log(a, a);
         }
         function f2(a, b) {
             a = 1 + (b = a);
@@ -7917,6 +7924,7 @@ issue_3744: {
 assign_value_def: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -7957,6 +7965,7 @@ join_vars_value_def: {
     options = {
         collapse_vars: true,
         join_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -7996,6 +8005,7 @@ join_vars_value_def: {
 var_value_def: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -8033,6 +8043,7 @@ var_value_def: {
 mangleable_var: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -8067,6 +8078,7 @@ mangleable_var: {
 mangleable_assignment_1: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -8098,6 +8110,7 @@ mangleable_assignment_1: {
 mangleable_assignment_2: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -8850,7 +8863,7 @@ issue_4732_1: {
     expect: {
         var a = 0;
         (function(b) {
-            (b = a++) && (b && console.log("PASS"));
+            (b = a++) && console.log("PASS");
         })(a++);
     }
     expect_stdout: "PASS"
@@ -8939,6 +8952,8 @@ dot_non_local: {
 issue_4806: {
     options = {
         collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
     }
     input: {
         var a, o = {
@@ -8962,6 +8977,7 @@ issue_4806: {
 issue_4852: {
     options = {
         collapse_vars: true,
+        unsafe: true,
     }
     input: {
         var a = "PASS";
@@ -9195,7 +9211,7 @@ issue_4918: {
     expect_stdout: "PASS"
 }
 
-issue_4920: {
+issue_4920_1: {
     options = {
         collapse_vars: true,
         toplevel: true,
@@ -9220,3 +9236,333 @@ issue_4920: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4920_2: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var o = {
+            get PASS() {
+                a = "FAIL";
+            },
+        };
+        var a = "PASS", b;
+        o[b = a];
+        console.log(b);
+    }
+    expect: {
+        var o;
+        var a = "PASS", b;
+        ({
+            get PASS() {
+                a = "FAIL";
+            },
+        })[b = a];
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4920_3: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var log = console.log;
+        var o = {
+            get PASS() {
+                a = "FAIL";
+            },
+        };
+        var a = "PASS", b;
+        o[b = a];
+        log(b);
+    }
+    expect: {
+        var log = console.log;
+        var o;
+        var a = "PASS", b;
+        ({
+            get PASS() {
+                a = "FAIL";
+            },
+        })[b = a];
+        log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4920_4: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var log = console.log;
+        var o = {
+            get [(a = "FAIL 1", "PASS")]() {
+                a = "FAIL 2";
+            },
+        };
+        var a = "PASS", b;
+        o[b = a];
+        log(b);
+    }
+    expect: {
+        var log = console.log;
+        var o = {
+            get [(a = "FAIL 1", "PASS")]() {
+                a = "FAIL 2";
+            },
+        };
+        var a = "PASS", b;
+        o[b = a];
+        log(b);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4935: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 1;
+        var b;
+        var c = b = a;
+        console || c(a++);
+        --b;
+        console.log(a, b);
+    }
+    expect: {
+        var a = 1;
+        var b;
+        var c = b = a;
+        console || a(a++);
+        --b;
+        console.log(a, b);
+    }
+    expect_stdout: "1 0"
+}
+
+inline_throw: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        keep_fargs: false,
+        unused: true,
+    }
+    input: {
+        try {
+            (function() {
+                return function(a) {
+                    return function(b) {
+                        throw b;
+                    }(a);
+                };
+            })()("PASS");
+        } catch (e) {
+            console.log(e);
+        }
+    }
+    expect: {
+        try {
+            (function(a) {
+                return function() {
+                    throw a;
+                }();
+            })("PASS");
+        } catch (e) {
+            console.log(e);
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4977_1: {
+    options = {
+        collapse_vars: true,
+        unsafe: true,
+    }
+    input: {
+        var a = "FAIL";
+        var o = {
+            get p() {
+                return a;
+            }
+        };
+        a = "PASS";
+        console.log(o.p, a);
+    }
+    expect: {
+        var a = "FAIL";
+        var o = {
+            get p() {
+                return a;
+            }
+        };
+        a = "PASS";
+        console.log(o.p, a);
+    }
+    expect_stdout: "PASS PASS"
+}
+
+issue_4977_2: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        unsafe: true,
+    }
+    input: {
+        var a, o = {
+            get p() {
+                return a = "PASS";
+            },
+        };
+        if (console) {
+            var a = "FAIL";
+            console.log(o.p, a);
+        }
+    }
+    expect: {
+        var a, o = {
+            get p() {
+                return a = "PASS";
+            },
+        };
+        if (console) {
+            var a = "FAIL";
+            console.log(o.p, a);
+        }
+    }
+    expect_stdout: "PASS PASS"
+}
+
+issue_5112_1: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        console.log(function(a) {
+            try {
+                try {
+                    if (console + (a = "PASS", ""))
+                        return "FAIL 1";
+                    a.p;
+                } catch (e) {}
+            } finally {
+                return a;
+            }
+        }("FAIL 2"));
+    }
+    expect: {
+        console.log(function(a) {
+            try {
+                try {
+                    if (console + (a = "PASS", ""))
+                        return "FAIL 1";
+                    a.p;
+                } catch (e) {}
+            } finally {
+                return a;
+            }
+        }("FAIL 2"));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5112_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        console.log(function(a) {
+            try {
+                return function() {
+                    try {
+                        if (console + (a = "PASS", ""))
+                            return "FAIL 1";
+                        a.p;
+                    } catch (e) {}
+                }();
+            } finally {
+                return a;
+            }
+        }("FAIL 2"));
+    }
+    expect: {
+        console.log(function(a) {
+            try {
+                return function() {
+                    try {
+                        if (console + (a = "PASS", ""))
+                            return "FAIL 1";
+                        a.p;
+                    } catch (e) {}
+                }();
+            } finally {
+                return a;
+            }
+        }("FAIL 2"));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5182: {
+    options = {
+        arrows: true,
+        collapse_vars: true,
+        evaluate: true,
+        hoist_props: true,
+        inline: true,
+        merge_vars: true,
+        passes: 4,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var con = console;
+        global.log = con.log;
+        var jump = function(x) {
+            console.log("JUMP:", x * 10);
+            return x + x;
+        };
+        var jump2 = jump;
+        var run = function(x) {
+            console.log("RUN:", x * -10);
+            return x * x;
+        };
+        var run2 = run;
+        var bar = (x, y) => {
+            console.log("BAR:", x + y);
+            return x - y;
+        };
+        var bar2 = bar;
+        var obj = {
+            foo: bar2,
+            go: run2,
+            not_used: jump2,
+        };
+        console.log(obj.foo(1, 2), global.log("PASS"));
+    }
+    expect: {
+        var con = console;
+        global.log = con.log,
+        console.log((console.log("BAR:", 3), -1), global.log("PASS"));
+    }
+    expect_stdout: [
+        "BAR: 3",
+        "PASS",
+        "-1 undefined",
+    ]
+    node_version: ">=4"
+}

test/compress/concat-strings.js

@@ -289,3 +289,18 @@ issue_3689: {
     }
     expect_stdout: "00"
 }
+
+issue_5145: {
+    options = {
+        strings: true,
+    }
+    input: {
+        var a = [];
+        console.log("" + a + ((a[0] = 4) + "2"));
+    }
+    expect: {
+        var a = [];
+        console.log("" + a + (a[0] = 4) + "2");
+    }
+    expect_stdout: "42"
+}

test/compress/conditionals.js

@@ -822,6 +822,33 @@ cond_13: {
     }
 }
 
+cond_14: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        side_effects: true,
+    }
+    input: {
+        function f(a) {
+            if (a)
+                if (a)
+                    console.log("PASS");
+                else
+                    console.log("FAIL");
+        }
+        f(null);
+        f(42);
+    }
+    expect: {
+        function f(a) {
+            a && console.log("PASS");
+        }
+        f(null);
+        f(42);
+    }
+    expect_stdout: "PASS"
+}
+
 ternary_boolean_consequent: {
     options = {
         booleans: true,

test/compress/const.js

@@ -486,7 +486,7 @@ do_continue: {
 
 catch_ie8_1: {
     options = {
-        ie8: true,
+        ie: true,
         unused: true,
     }
     input: {
@@ -506,7 +506,7 @@ catch_ie8_1: {
 catch_ie8_2: {
     options = {
         dead_code: true,
-        ie8: true,
+        ie: true,
         passes: 2,
         toplevel: true,
         unused: true,
@@ -727,7 +727,7 @@ issue_4193: {
 
 issue_4195: {
     mangle = {
-        ie8: true,
+        ie: true,
     }
     input: {
         console.log(function f(a) {
@@ -1131,7 +1131,7 @@ issue_4225: {
 
 issue_4229: {
     options = {
-        ie8: true,
+        ie: true,
         side_effects: true,
     }
     input: {
@@ -1151,7 +1151,7 @@ issue_4229: {
 
 issue_4231: {
     options = {
-        ie8: true,
+        ie: true,
         side_effects: true,
     }
     input: {
@@ -1535,3 +1535,160 @@ issue_4848: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4954_1: {
+    rename = true
+    input: {
+        "use strict";
+        (function() {
+            {
+                const a = "foo";
+                console.log(a);
+            }
+            {
+                const a = "bar";
+                console.log(a);
+            }
+        })();
+    }
+    expect: {
+        "use strict";
+        (function() {
+            {
+                const a = "foo";
+                console.log(a);
+            }
+            {
+                const b = "bar";
+                console.log(b);
+            }
+        })();
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    node_version: ">=4"
+}
+
+issue_4954_2: {
+    mangle = {}
+    input: {
+        "use strict";
+        const a = null;
+        (function(b) {
+            for (const a in null);
+            for (const a in b)
+                console.log("PASS");
+        })([ null ]);
+    }
+    expect: {
+        "use strict";
+        const a = null;
+        (function(o) {
+            for (const n in null);
+            for (const n in o)
+                console.log("PASS");
+        })([ null ]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4960: {
+    mangle = {}
+    input: {
+        "use strict";
+        var a;
+        (function() {
+            {
+                const a = console.log("PASS");
+            }
+            try {} catch (e) {
+                const a = console.log("FAIL");
+            }
+        })();
+    }
+    expect: {
+        "use strict";
+        var a;
+        (function() {
+            {
+                const o = console.log("PASS");
+            }
+            try {} catch (o) {
+                const c = console.log("FAIL");
+            }
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4965_1: {
+    mangle = {}
+    input: {
+        "use strict";
+        try {
+            c;
+        } catch (a) {
+            {
+                const a = 1;
+            }
+            {
+                const a = console.log(typeof c);
+            }
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            c;
+        } catch (t) {
+            {
+                const c = 1;
+            }
+            {
+                const t = console.log(typeof c);
+            }
+        }
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}
+
+issue_4965_2: {
+    mangle = {}
+    input: {
+        "use strict";
+        try {
+            throw 1;
+        } catch (e) {
+            try {
+                {
+                    const e = 2;
+                }
+            } finally {
+                const e = 3;
+                console.log(typeof t);
+            }
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            throw 1;
+        } catch (o) {
+            try {
+                {
+                    const t = 2;
+                }
+            } finally {
+                const o = 3;
+                console.log(typeof t);
+            }
+        }
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}

test/compress/dead-code.js

@@ -939,6 +939,185 @@ catch_return_assign: {
     expect_stdout: "PASS"
 }
 
+catch_return_assign_may_throw: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        function f() {
+            try {
+                throw "FAIL";
+            } catch (e) {
+                return e = console.log("PASS");
+            }
+        }
+        f();
+    }
+    expect: {
+        function f() {
+            try {
+                throw "FAIL";
+            } catch (e) {
+                return console.log("PASS");
+            }
+        }
+        f();
+    }
+    expect_stdout: "PASS"
+}
+
+finally_return_assign: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        console.log(function(a) {
+            try {
+                throw "FAIL";
+            } finally {
+                return a = "PASS";
+            }
+        }());
+    }
+    expect: {
+        console.log(function(a) {
+            try {
+                throw "FAIL";
+            } finally {
+                return "PASS";
+            }
+        }());
+    }
+    expect_stdout: "PASS"
+}
+
+last_assign_statement: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        function f(a) {
+            a = a("PASS");
+        }
+        f(console.log);
+    }
+    expect: {
+        function f(a) {
+            a("PASS");
+        }
+        f(console.log);
+    }
+    expect_stdout: "PASS"
+}
+
+last_assign_if_else: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        function f(a) {
+            if (a)
+                a = console.log("foo");
+            else {
+                console.log("bar");
+                a = console.log("baz");
+            }
+        }
+        f(42);
+        f(null);
+    }
+    expect: {
+        function f(a) {
+            if (a)
+                console.log("foo");
+            else {
+                console.log("bar");
+                console.log("baz");
+            }
+        }
+        f(42);
+        f(null);
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "baz",
+    ]
+}
+
+last_assign_catch: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        function f() {
+            try {
+                throw "FAIL";
+            } catch (e) {
+                e = console.log("PASS");
+            }
+        }
+        f();
+    }
+    expect: {
+        function f() {
+            try {
+                throw "FAIL";
+            } catch (e) {
+                console.log("PASS");
+            }
+        }
+        f();
+    }
+    expect_stdout: "PASS"
+}
+
+last_assign_finally: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        function f(a) {
+            try {
+                throw a.log;
+            } catch (e) {
+                a = e;
+            } finally {
+                a = a("PASS");
+            }
+        }
+        f(console);
+    }
+    expect: {
+        function f(a) {
+            try {
+                throw a.log;
+            } catch (e) {
+                a = e;
+            } finally {
+                a("PASS");
+            }
+        }
+        f(console);
+    }
+    expect_stdout: "PASS"
+}
+
+consecutive_assignments: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        while (a = void 0, a = "PASS", console.log(a));
+        var a;
+    }
+    expect: {
+        while (void 0, a = "PASS", console.log(a));
+        var a;
+    }
+    expect_stdout: "PASS"
+}
+
 issue_3578: {
     options = {
         dead_code: true,
@@ -1420,3 +1599,73 @@ issue_4570: {
     }
     expect_stdout: "NaN"
 }
+
+issue_5030: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        (function(a, b) {
+            a = function f() {
+                if (a)
+                    if (b--)
+                        setImmediate(f);
+                    else
+                        console.log("FAIL");
+                else
+                    console.log("PASS");
+            }();
+        })(42, 1);
+    }
+    expect: {
+        (function(a, b) {
+            a = function f() {
+                if (a)
+                    if (b--)
+                        setImmediate(f);
+                    else
+                        console.log("FAIL");
+                else
+                    console.log("PASS");
+            }();
+        })(42, 1);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=0.12"
+}
+
+issue_5106_1: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        console.log(typeof function(a) {
+            return a = arguments;
+        }("FAIL")[0]);
+    }
+    expect: {
+        console.log(typeof function(a) {
+            return a = arguments;
+        }("FAIL")[0]);
+    }
+    expect_stdout: "object"
+}
+
+issue_5106_2: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        "use strict";
+        console.log(function(a) {
+            return a = arguments;
+        }("PASS")[0]);
+    }
+    expect: {
+        "use strict";
+        console.log(function(a) {
+            return arguments;
+        }("PASS")[0]);
+    }
+    expect_stdout: "PASS"
+}

test/compress/default-values.js

@@ -70,7 +70,7 @@ object_shorthand_assign: {
         ({ a = "PASS" } = 42);
         console.log(a);
     }
-    expect_exact: '({a:a="PASS"}=42);console.log(a);'
+    expect_exact: '({a="PASS"}=42);console.log(a);'
     expect_stdout: "PASS"
     node_version: ">=6"
 }
@@ -80,7 +80,7 @@ object_shorthand_declaration: {
         var { a = "PASS" } = 42;
         console.log(a);
     }
-    expect_exact: 'var{a:a="PASS"}=42;console.log(a);'
+    expect_exact: 'var{a="PASS"}=42;console.log(a);'
     expect_stdout: "PASS"
     node_version: ">=6"
 }
@@ -91,7 +91,7 @@ object_shorthand_function: {
             console.log(a);
         })(42);
     }
-    expect_exact: '(function({a:a="PASS"}){console.log(a)})(42);'
+    expect_exact: '(function({a="PASS"}){console.log(a)})(42);'
     expect_stdout: "PASS"
     node_version: ">=6"
 }
@@ -149,7 +149,7 @@ process_boolean_returns: {
     }
     expect: {
         console.log(function(a = console.log("FAIL 1")) {
-            return a() ? "PASS" : "FAIL 2";
+            return 42 ? "PASS" : "FAIL 2";
         }(function() {
             return 1;
         }));
@@ -245,21 +245,64 @@ maintain_if: {
     node_version: ">=6"
 }
 
-reduce_value: {
+reduce_funarg: {
     options = {
         evaluate: true,
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
     input: {
-        console.log(function(a = "PASS") {
+        console.log(...function(a = "foo", b = "bar", c = "baz") {
-            return a;
+            return [ a, b, c ];
-        }());
+        }(void 0, null));
     }
     expect: {
-        console.log("PASS");
+        console.log(...function() {
+            return [ "foo", null, "baz" ];
+        }());
     }
-    expect_stdout: "PASS"
+    expect_stdout: "foo null baz"
+    node_version: ">=6"
+}
+
+reduce_array: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var [ a = "foo", b = "bar", c = "baz" ] = [ void 0, null ];
+        console.log(a, b, c);
+    }
+    expect: {
+        var [ c = "baz" ] = [];
+        console.log("foo", null, c);
+    }
+    expect_stdout: "foo null baz"
+    node_version: ">=6"
+}
+
+reduce_object: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var { a = "foo", b = "bar", c = "baz" } = { a: void 0, b: null };
+        console.log(a, b, c);
+    }
+    expect: {
+        var { c = "baz" } = {};
+        console.log("foo", null, c);
+    }
+    expect_stdout: "foo null baz"
     node_version: ">=6"
 }
 
@@ -422,7 +465,9 @@ inline_loop_1: {
 inline_loop_2: {
     options = {
         inline: true,
+        sequences: true,
         toplevel: true,
+        unused: true,
     }
     input: {
         while (function(a = [ "PASS" ]) {
@@ -432,10 +477,11 @@ inline_loop_2: {
         }());
     }
     expect: {
-        while (a = [ "PASS" ], a = function f(b) {
+        while (a = [ "PASS" ],
-            console.log(a[b]);
+            b = void 0,
-        }(0), void 0) ;
+            b = 0,
-        var a;
+            void (a = void console.log(a[b])));
+        var a, b;
     }
     expect_stdout: "PASS"
     node_version: ">=6"
@@ -522,6 +568,20 @@ retain_empty_iife: {
     node_version: ">=6"
 }
 
+drop_new_function: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        new function(a = console.log("PASS")) {}();
+    }
+    expect: {
+        void console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 retain_fargs: {
     options = {
         unused: true,
@@ -598,6 +658,7 @@ unused_var_1: {
 
 unused_var_2: {
     options = {
+        pure_getters: "strict",
         toplevel: true,
         unused: true,
     }
@@ -609,11 +670,7 @@ unused_var_2: {
         };
     }
     expect: {
-        var {
+        console.log("PASS");
-            p: [] = [ console.log("FAIL") ],
-        } = {
-            p: [ console.log("PASS") ],
-        };
     }
     expect_stdout: "PASS"
     node_version: ">=6"
@@ -676,7 +733,7 @@ unused_value_var_2: {
         console.log(a);
     }
     expect: {
-        var [ a ] = [ "PASS" ];
+        var a = [ "PASS" ][0];
         console.log(a);
     }
     expect_stdout: "PASS"
@@ -980,7 +1037,7 @@ mangle_arrow_1: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.3"
 }
 
 mangle_arrow_1_toplevel: {
@@ -1016,7 +1073,7 @@ mangle_arrow_1_toplevel: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.3"
 }
 
 mangle_arrow_2: {
@@ -1052,7 +1109,7 @@ mangle_arrow_2: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.3"
 }
 
 mangle_arrow_2_toplevel: {
@@ -1088,7 +1145,7 @@ mangle_arrow_2_toplevel: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.3"
 }
 
 issue_4444: {
@@ -1257,7 +1314,7 @@ issue_4468: {
     expect: {
         (function() {
             var {
-                [console.log("PASS")]: b = 0,
+                [console.log("PASS")]: b,
             } = 0;
         })();
     }
@@ -1416,6 +1473,7 @@ issue_4502_1: {
     expect: {
         (function() {
             var a = "PASS";
+            void 0,
             console.log(a),
             a++,
             void 0;
@@ -1439,6 +1497,7 @@ issue_4502_2: {
     expect: {
         (function() {
             var a = "PASS";
+            void 0,
             console.log(a),
             a++,
             void 0;
@@ -1528,7 +1587,7 @@ issue_4510_2: {
         };
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4523: {
@@ -1664,7 +1723,7 @@ issue_4588_2_evaluate: {
 
 issue_4817: {
     options = {
-        ie8: true,
+        ie: true,
         inline: true,
         unused: true,
     }
@@ -1698,7 +1757,7 @@ issue_4854: {
         }());
     }
     expect: {
-        console.log(void ([] = "foo"));
+        console.log(void 0);
     }
     expect_stdout: "undefined"
     node_version: ">=6"
@@ -1729,3 +1788,172 @@ issue_4916: {
     expect_stdout: "undefined"
     node_version: ">=6"
 }
+
+issue_4994: {
+    options = {
+        loops: true,
+        unused: true,
+    }
+    input: {
+        var a = "FAIL";
+        (function(b = function() {
+            for (a in { PASS: 42 });
+        }()) {
+            var a;
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = "FAIL";
+        (function(b = function() {
+            for (a in { PASS: 42 });
+        }()) {})();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5057_1: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        sequences: true,
+        unused: true,
+    }
+    input: {
+        var a = 42;
+        (function() {
+            var b = function(c = (console.log("foo"), b = a)) {
+                a && console.log("bar");
+            }();
+        })();
+    }
+    expect: {
+        var a = 42;
+        console.log("foo"),
+        void (a && console.log("bar"));
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    node_version: ">=6"
+}
+
+issue_5057_2: {
+    options = {
+        inline: true,
+        unused: true,
+    }
+    input: {
+        (function f(a) {
+            (function(b = console.log("FAIL")) {})(a);
+        })(42);
+        console.log(typeof b);
+    }
+    expect: {
+        (function(a) {
+            [ b = console.log("FAIL") ] = [ a ],
+            void 0;
+            var b;
+        })(42);
+        console.log(typeof b);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+issue_5057_3: {
+    options = {
+        inline: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            (function f(b) {
+                (function(a = console.log("FAIL 1")) {})(b);
+                console.log(a);
+            })("FAIL 2");
+        })("PASS");
+    }
+    expect: {
+        (function(a) {
+            (function(b) {
+                (function(a = console.log("FAIL 1")) {})(b);
+                console.log(a);
+            })("FAIL 2");
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5065: {
+    options = {
+        pure_getters: "strict",
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var [ a = console.log("PASS") ] = [ (A = 42).p ];
+    }
+    expect: {
+        var [ a = console.log("PASS") ] = [ (A = 42).p ];
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5138_1: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log(function(a, b = a = "FAIL") {
+            return a;
+        }() && "PASS");
+    }
+    expect: {
+        console.log(function(a, b = a = "FAIL") {
+            return a;
+        }() && "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5138_2: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log(function(a, b = a = "FAIL 1") {
+            return a;
+        }(null, "FAIL 2") || "PASS");
+    }
+    expect: {
+        console.log((null, "PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5192: {
+    options = {
+        dead_code: true,
+        ie: true,
+    }
+    input: {
+        (function a(a,  [] = a = "PASS") {
+            console.log(a);
+        })("FAIL");
+    }
+    expect: {
+        (function a(a,  [] = a = "PASS") {
+            console.log(a);
+        })("FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/compress/destructured.js

@@ -220,7 +220,7 @@ funarg_side_effects_2: {
         }
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.2"
 }
 
 funarg_side_effects_3: {
@@ -254,7 +254,7 @@ funarg_side_effects_3: {
         }
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.2"
 }
 
 funarg_unused_1: {
@@ -1010,6 +1010,42 @@ collapse_vars_8: {
     node_version: ">=6"
 }
 
+collapse_vars_9: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        console.log(function(a) {
+            try {
+                var b = function([ c ]) {
+                    if (c)
+                        return "FAIL 1";
+                }();
+                a = "FAIL 2";
+                return b;
+            } catch (e) {
+                return a;
+            }
+        }("PASS"));
+    }
+    expect: {
+        console.log(function(a) {
+            try {
+                var b = function([ c ]) {
+                    if (c)
+                        return "FAIL 1";
+                }();
+                a = "FAIL 2";
+                return b;
+            } catch (e) {
+                return a;
+            }
+        }("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 conditionals: {
     options = {
         conditionals: true,
@@ -1069,7 +1105,7 @@ drop_unused_1: {
             try {
                 throw 42;
             } catch (a) {
-                var [ a ] = [];
+                var a = [][0];
             }
         }
     }
@@ -1102,6 +1138,175 @@ drop_unused_2: {
     node_version: ">=6"
 }
 
+drop_hole: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var [ a ] = [ , ];
+        console.log(a);
+    }
+    expect: {
+        var a = [][0];
+        console.log(a);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+keep_key_1: {
+    options = {
+        evaluate: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = {
+            [(console.log("PASS"), 42)]: null,
+        });
+    }
+    expect: {
+        ({} = {
+            [(console.log("PASS"), 42)]: 0,
+        });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_key_2: {
+    options = {
+        evaluate: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { 42: a } = { [(console.log("PASS"), 42)](){} };
+    }
+    expect: {
+        var {} = { [(console.log("PASS"), 42)]: 0 };
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_key_2_pure_getters: {
+    options = {
+        evaluate: true,
+        pure_getters: "strict",
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { 42: a } = { [(console.log("PASS"), 42)](){} };
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_reference: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = [ {}, 42 ];
+        var [ b, c ] = a;
+        console.log(a[0] === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = [ {}, 42 ];
+        var [ b ] = a;
+        console.log(a[0] === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+maintain_position_assign: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(([ , ] = [ , "PASS" ])[1]);
+    }
+    expect: {
+        console.log([ , "PASS" ][1]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+maintain_position_var: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        A = "FAIL";
+        var [ a, b ] = [ A ];
+        console.log(b || "PASS");
+    }
+    expect: {
+        A = "FAIL";
+        var [ , b ] = [ A ];
+        console.log(b || "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+side_effects_array: {
+    options = {
+        unused: true,
+    }
+    input: {
+        try {
+            var [ a ] = 42;
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            var [ a ] = 42;
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+side_effects_object: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = null, b = console, { c } = 42;
+        try {
+            c[a = "PASS"];
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect: {
+        var a = null, c = (console, 42["c"]);
+        try {
+            c[a = "PASS"];
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 join_vars: {
     options = {
         conditionals: true,
@@ -1376,6 +1581,75 @@ hoist_vars: {
     node_version: ">=6"
 }
 
+singleton_1: {
+    options = {
+        pure_getters: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var [ a ] = "P", b, o = {};
+        [ { 1: o.p } ] = [ "FAIL" ];
+        ({ foo: [ o.q ] } = { foo: "S" });
+        [ b = "S" ] = [];
+        console.log(a + o.p + o.q + b);
+    }
+    expect: {
+        var b, a = "P"[0], o = {};
+        o.p = [ "FAIL"["1"] ][0];
+        o.q = { foo: "S"[0] }["foo"];
+        [ b = "S" ] = [];
+        console.log(a + o.p + o.q + b);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+singleton_2: {
+    options = {
+        evaluate: true,
+        passes: 2,
+        pure_getters: true,
+        side_effects: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var [ a ] = "P", b, o = {};
+        [ { 1: o.p } ] = [ "FAIL" ];
+        ({ foo: [ o.q ] } = { foo: "S" });
+        [ b = "S" ] = [];
+        console.log(a + o.p + o.q + b);
+    }
+    expect: {
+        var b, a = "P", o = {};
+        o.p = "A";
+        o.q = "S";
+        [ b = "S" ] = [];
+        console.log(a + o.p + o.q + b);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+singleton_side_effects: {
+    options = {
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        [ 42[console.log("foo")] ] = [ console.log("bar") ];
+    }
+    expect: {
+        [ 42[console.log("foo")] ] = [ console.log("bar") ];
+    }
+    expect_stdout: [
+        "bar",
+        "foo",
+    ]
+    node_version: ">=6"
+}
+
 issue_4280: {
     options = {
         evaluate: true,
@@ -1824,7 +2098,7 @@ issue_4321: {
 
 issue_4323: {
     options = {
-        ie8: true,
+        ie: true,
         inline: true,
         merge_vars: true,
         reduce_vars: true,
@@ -1922,7 +2196,7 @@ issue_4372_2: {
     }
     expect: {
         var a;
-        [ a ] = [ "PASS", "FAIL" ];
+        [ a ] = a = [ "PASS", "FAIL" ];
         console.log(a);
     }
     expect_stdout: "PASS"
@@ -2556,3 +2830,539 @@ issue_4608_2: {
     expect_stdout: "f"
     node_version: ">=6"
 }
+
+issue_4994: {
+    options = {
+        loops: true,
+        unused: true,
+    }
+    input: {
+        var a = "FAIL";
+        (function([
+            {
+                [function() {
+                    for (a in { PASS: null });
+                }()]: b,
+            },
+        ]) {
+            var a;
+        })([ 42 ]);
+        console.log(a);
+    }
+    expect: {
+        var a = "FAIL";
+        (function([
+            {
+                [function() {
+                    for (a in { PASS: null });
+                }()]: b,
+            },
+        ]) {})([ 42 ]);
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5017: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = function() {};
+        var b = c = a;
+        var c = [ c ] = [ c ];
+        console.log(c[0] === a ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = function() {};
+        var b = a;
+        var c = [ c ] = [ c = a ];
+        console.log(c[0] === a ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5071_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var a;
+        console.log(([ , a ] = [ "PA", , ]).join("SS"));
+    }
+    expect: {
+        var a;
+        console.log(([ , a ] = [ "PA", , ]).join("SS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5071_2: {
+    options = {
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        var a;
+        ([ a ] = []).p = console.log("PASS");
+    }
+    expect: {
+        var a;
+        ([ a ] = []).p = console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_getter: {
+    options = {
+        evaluate: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { get [(console.log("PASS"), 42)]() {} });
+    }
+    expect: {
+        ({} = { [(console.log("PASS"), 42)]: 0 });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_getter_pure_getters: {
+    options = {
+        evaluate: true,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { get [(console.log("PASS"), 42)]() {} });
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_setter: {
+    options = {
+        evaluate: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { set [(console.log("PASS"), 42)](v) {} });
+    }
+    expect: {
+        ({} = { [(console.log("PASS"), 42)]: 0 });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_setter_pure_getters: {
+    options = {
+        evaluate: true,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { set [(console.log("PASS"), 42)](v) {} });
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_method: {
+    options = {
+        evaluate: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { [(console.log("PASS"), 42)]() {} });
+    }
+    expect: {
+        ({} = { [(console.log("PASS"), 42)]: 0 });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_method_pure_getters: {
+    options = {
+        evaluate: true,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { [(console.log("PASS"), 42)]() {} });
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5085_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        var [ b ] = [ 42, a ], c = b ? 0 : a = "FAIL";
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        var b = [ 42 ][0];
+        b;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5085_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        side_effects: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function(b) {
+            [ b ] = [ 42, a ];
+            var c = b ? 0 : a = "FAIL";
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        (function(b) {
+            b = [ 42 ][0];
+        })();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5087_1: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        properties: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function() {
+            (function() {
+                (function([ b ]) {
+                    b && console.log(b);
+                })([ a ]);
+            })();
+        })();
+    }
+    expect: {
+        var a = "PASS";
+        (function() {
+            var b;
+            (b = a) && console.log(b);
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5087_2: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        passes: 2,
+        properties: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function() {
+            (function() {
+                (function([ b ]) {
+                    b && console.log(b);
+                })([ a ]);
+            })();
+        })();
+    }
+    expect: {
+        var a = "PASS";
+        a && console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5114_1: {
+    options = {
+        inline: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function({}, a) {})(42);
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        [ {} ] = [ 42 ],
+        void 0;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5114_2: {
+    options = {
+        inline: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function f([], a) {
+            f.length;
+        })([]);
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        0;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5114_3: {
+    options = {
+        inline: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function f(a, {}) {
+            f.length;
+        })(null, 42);
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        0;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5153_array_assign: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = function*() {
+            yield b;
+        }(), b;
+        [ b ] = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = function*() {
+            yield b;
+        }(), b;
+        [ b ] = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5153_array_var: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = function*() {
+            yield b;
+        }(), [ b ] = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = function*() {
+            yield b;
+        }(), [ b ] = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5153_object_assign: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = {
+            get p() {
+                return b;
+            },
+        }, b;
+        ({
+            p: b
+        } = b = a);
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = {
+            get p() {
+                return b;
+            },
+        }, b;
+        ({
+            p: b
+        } = b = a);
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5153_object_var: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = {
+            get p() {
+                return b;
+            },
+        }, {
+            p: b
+        } = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = {
+            get p() {
+                return b;
+            },
+        }, {
+            p: b
+        } = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5168: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        (function a({
+            [console.log(typeof function() {
+                ++a;
+                return a;
+            }())]: b,
+        }) {
+            var a;
+        })({});
+    }
+    expect: {
+        (function a({
+            [console.log(typeof function() {
+                ++a;
+                return a;
+            }())]: b,
+        }) {
+            var a;
+        })({});
+    }
+    expect_stdout: "function"
+    node_version: ">=6"
+}
+
+issue_5189_1: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 42;
+        [ a.p ] = a = "PASS";
+        console.log(a);
+    }
+    expect: {
+        var a;
+        [ a.p ] = a = "PASS";
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5189_2: {
+    options = {
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 42;
+        ({ p: a.q } = a = "PASS");
+        console.log(a);
+    }
+    expect: {
+        var a;
+        ({ p: a.q } = a = "PASS");
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/compress/drop-unused.js

@@ -795,9 +795,9 @@ issue_1656: {
         beautify: true,
     }
     input: {
-        for(var a=0;;);
+        for (var a=0;;);
     }
-    expect_exact: "for (;;) ;"
+    expect_exact: "for (;;);"
 }
 
 issue_1709: {
@@ -1110,7 +1110,7 @@ issue_1838: {
     }
     expect_exact: [
         "function f() {",
-        "    for (a; c; ) ;",
+        "    for (a; c; );",
         "}",
     ]
 }
@@ -1557,9 +1557,9 @@ issue_2665: {
     }
     expect: {
         var a = 1;
-        !function g() {
+        (function g() {
             a-- && g();
-        }();
+        })();
         console.log(a);
     }
     expect_stdout: "-1"
@@ -2345,7 +2345,7 @@ function_argument_reference: {
 
 function_parameter_ie8: {
     options = {
-        ie8: true,
+        ie: true,
         reduce_vars: true,
         unused: true,
     }
@@ -2916,7 +2916,7 @@ issue_4133: {
         console.log(a);
     }
     expect: {
-        var b = 1;
+        var a = 1;
         console.log(0);
     }
     expect_stdout: "0"
@@ -3062,7 +3062,7 @@ issue_4184: {
     expect_stdout: "42"
 }
 
-issue_4235: {
+issue_4235_1: {
     options = {
         inline: true,
         reduce_vars: true,
@@ -3080,12 +3080,35 @@ issue_4235: {
         })();
     }
     expect: {
+        void function() {
+            var f = console.log(f);
+        }();
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4235_2: {
+    options = {
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
         (function() {
-            f = console.log(f),
+            {
-            void 0;
+                const f = 0;
-            var f;
+            }
+            (function f() {
+                var f = console.log(f);
+            })();
         })();
     }
+    expect: {
+        console.log(void 0);
+    }
     expect_stdout: "undefined"
 }
 
@@ -3231,7 +3254,7 @@ issue_4558_1: {
 issue_4558_2: {
     options = {
         evaluate: true,
-        ie8: true,
+        ie: true,
         reduce_vars: true,
         unused: true,
     }
@@ -3380,7 +3403,7 @@ issue_4834: {
     }
     expect: {
         try {
-            void b.p;
+            b.p;
         } catch (e) {
             console.log("PASS");
         }
@@ -3436,7 +3459,7 @@ issue_4912_2: {
         console.log(function() {
             var g, f = function() {};
             f.p = {};
-            (g = f.p.q = function() {}).r = "PASS";
+            (f.p.q = function() {}).r = "PASS";
             return f;
         }().p.q.r);
     }
@@ -3470,3 +3493,26 @@ issue_4912_3: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5079: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        do {
+            (a = 123456).p = a;
+            a.q = null;
+        } while (console.log("PASS"));
+    }
+    expect: {
+        do {
+            0, 0, null;
+        } while (console.log("PASS"));
+    }
+    expect_stdout: "PASS"
+}

test/compress/evaluate.js

@@ -684,26 +684,47 @@ prototype_function: {
         side_effects: true,
     }
     input: {
-        var a = ({valueOf: 0}) < 1;
+        function v() {
-        var b = ({toString: 0}) < 1;
+            return this.valueOf === v ? "PASS" : "FAIL";
-        var c = ({valueOf: 0}) + "";
+        }
-        var d = ({toString: 0}) + "";
+        console.log(({ valueOf: v }) < 1);
-        var e = (({valueOf: 0}) + "")[2];
+        console.log(({ valueOf: v }) + "");
-        var f = (({toString: 0}) + "")[2];
+        console.log((( {valueOf: v }) + "")[2]);
-        var g = ({valueOf: 0}).valueOf();
+        console.log(({ valueOf: v }).valueOf());
-        var h = ({toString: 0}).toString();
+        function t() {
+            return this.toString === t ? "PASS" : "FAIL";
+        }
+        console.log(({ toString: t }) < 1);
+        console.log(({ toString: t }) + "");
+        console.log((( {toString: t }) + "")[2]);
+        console.log(({ toString: t }).toString());
     }
     expect: {
-        var a = ({valueOf: 0}) < 1;
+        function v() {
-        var b = ({toString: 0}) < 1;
+            return this.valueOf === v ? "PASS" : "FAIL";
-        var c = ({valueOf: 0}) + "";
+        }
-        var d = ({toString: 0}) + "";
+        console.log(({ valueOf: v }) < 1);
-        var e = (({valueOf: 0}) + "")[2];
+        console.log(({ valueOf: v }) + "");
-        var f = (({toString: 0}) + "")[2];
+        console.log((( {valueOf: v }) + "")[2]);
-        var g = 0();
+        console.log(({ valueOf: v }).valueOf());
-        var h = 0();
+        function t() {
+            return this.toString === t ? "PASS" : "FAIL";
+        }
+        console.log(({ toString: t }) < 1);
+        console.log(({ toString: t }) + "");
+        console.log((( {toString: t }) + "")[2]);
+        console.log(({ toString: t }).toString());
     }
-    expect_stdout: true
+    expect_stdout: [
+        "false",
+        "PASS",
+        "S",
+        "PASS",
+        "false",
+        "PASS",
+        "S",
+        "PASS",
+    ]
 }
 
 call_args: {
@@ -3182,7 +3203,7 @@ issue_4552: {
     expect_stdout: "NaN"
 }
 
-issue_4886: {
+issue_4886_1: {
     options = {
         evaluate: true,
         unsafe: true,
@@ -3201,3 +3222,23 @@ issue_4886: {
     }
     expect_stdout: "true"
 }
+
+issue_4886_2: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        console.log("foo" in {
+            "foo": null,
+            __proto__: 42,
+        });
+    }
+    expect: {
+        console.log("foo" in {
+            "foo": null,
+            __proto__: 42,
+        });
+    }
+    expect_stdout: "true"
+}

test/compress/exponentiation.js

@@ -62,7 +62,7 @@ assignment_2: {
     }
     expect_exact: "var a=8n;a**=a;console.log(a);"
     expect_stdout: "16777216n"
-    node_version: ">=10"
+    node_version: ">=10.4.0"
 }
 
 evaluate: {
@@ -99,8 +99,8 @@ issue_4664: {
     expect: {
         (function f() {
             new function(a) {
-                console.log(typeof f, 1073741824, typeof this);
+                console.log(typeof f, a, typeof this);
-            }(A = 0);
+            }((A = 0, 2 ** 30));
         })();
     }
     expect_stdout: "function 1073741824 object"

test/compress/exports.js

@@ -249,7 +249,7 @@ hoist_exports_2: {
         }
     }
     expect: {
-        let e, { foo: a } = 42;
+        let e, a = 42["foo"];
         function f(t, { [e]: o }) {
             t(o, f);
         }

test/compress/functions.js

@@ -1171,11 +1171,11 @@ issue_2620_4: {
     }
     expect: {
         var c = "FAIL";
-        !function() {
+        (function() {
             switch (NaN) {
               case void (c = "PASS"):
             }
-        }();
+        })();
         console.log(c);
     }
     expect_stdout: "PASS"
@@ -2123,7 +2123,7 @@ issue_3016_2: {
 issue_3016_2_ie8: {
     options = {
         dead_code: true,
-        ie8: true,
+        ie: true,
         inline: true,
         toplevel: true,
     }
@@ -2188,7 +2188,7 @@ issue_3016_3: {
 issue_3016_3_ie8: {
     options = {
         dead_code: true,
-        ie8: true,
+        ie: true,
         inline: true,
         toplevel: true,
     }
@@ -2826,6 +2826,36 @@ functions_use_strict: {
     expect_stdout: "a true 42 function function function"
 }
 
+functions_cross_scope_reference: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        log = function(fn) {
+            console.log(typeof fn());
+        };
+        var a = function() {};
+        function f() {
+            return a;
+        }
+        while (log(f));
+    }
+    expect: {
+        log = function(fn) {
+            console.log(typeof fn());
+        };
+        function a() {}
+        function f() {
+            return a;
+        }
+        while (log(f));
+    }
+    expect_stdout: "function"
+}
+
 functions_inner_var: {
     options = {
         functions: true,
@@ -2905,6 +2935,7 @@ issue_2437: {
 issue_2485_1: {
     options = {
         functions: true,
+        passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
         unused: true,
@@ -2955,6 +2986,7 @@ issue_2485_2: {
     options = {
         functions: true,
         inline: true,
+        passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
         unused: true,
@@ -4825,8 +4857,9 @@ issue_4155: {
     }
     expect: {
         (function() {
-            void console.log(b);
+            var a;
-            var b = function() {};
+            void console.log(a);
+            function b() {}
             b && console.log(typeof b);
         })();
     }
@@ -5236,7 +5269,7 @@ issue_4265: {
     expect: {
         function f() {
             return console, function() {
-                return console.log(a);
+                console.log(a);
                 var a;
             }(), 0;
         }
@@ -6208,3 +6241,464 @@ reduce_cross_reference_4_toplevel: {
     expect: {}
     expect_stdout: true
 }
+
+recursive_collapse: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+    }
+    input: {
+        console.log(function f(a) {
+            var b = a && f();
+            return b;
+        }("FAIL") || "PASS");
+    }
+    expect: {
+        console.log(function f(a) {
+            var b;
+            return a && f();
+        }("FAIL") || "PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5025: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            function g() {
+                b = 42;
+            }
+            g(b = a);
+            var b = this;
+            console.log(typeof b);
+        }
+        f();
+    }
+    expect: {
+        function f(a) {
+            b = a,
+            void (b = 42);
+            var b = this;
+            console.log(typeof b);
+        }
+        f();
+    }
+    expect_stdout: "object"
+}
+
+issue_5036: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(typeof function() {
+            var await = function f() {
+                return f;
+            };
+            return await() === await;
+        }() ? "PASS" : "FAIL");
+    }
+    expect: {
+        console.log(typeof function() {
+            function await() {
+                return await;
+            }
+            return await() === await;
+        }() ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5046: {
+    options = {
+        conditionals: true,
+        evaluate: true,
+        keep_fnames: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0;
+        if (a)
+            0();
+        else
+            (function f() {
+                f;
+                return a = "PASS";
+            })();
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        (a ? 0 : function f() {
+            return a = "PASS";
+        })();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5061_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var f, a = 1;
+        (f = function() {
+            console.log(a ? "foo" : "bar");
+        })();
+        f(a = 0);
+    }
+    expect: {
+        var f, a = 1;
+        (f = function() {
+            console.log(a ? "foo" : "bar");
+        })();
+        f(a = 0);
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_5061_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f, a = 1;
+        (f = function() {
+            console.log(a ? "foo" : "bar");
+        })();
+        f(a = 0);
+    }
+    expect: {
+        var f, a = 1;
+        (f = function() {
+            console.log(a ? "foo" : "bar");
+        })();
+        f(a = 0);
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_5067: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f = function() {
+            f();
+        };
+    }
+    expect: {}
+}
+
+issue_5096_1: {
+    options = {
+        evaluate: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b = "FAIL", c = 1;
+        do {
+            a && a();
+            a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect: {
+        var a, b = "FAIL", c = 1;
+        do {
+            a && a();
+            a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5096_2: {
+    options = {
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b = "FAIL", c = 1;
+        do {
+            a && a();
+            a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect: {
+        var a, b = "FAIL", c = 1;
+        do {
+            a && a();
+            a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5096_3: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var b = "FAIL", c = 1;
+        do {
+            a && a();
+            var a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect: {
+        var b = "FAIL", c = 1;
+        do {
+            a && a();
+            var a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5096_4: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var b = "FAIL", c = 1;
+        do {
+            a && a();
+            var a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect: {
+        var b = "FAIL", c = 1;
+        do {
+            a && a();
+            var a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5098: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(o) {
+            function f() {
+                f = console.log;
+                if (o.p++)
+                    throw "FAIL";
+                f("PASS");
+            }
+            return f;
+        })({ p: 0 })();
+    }
+    expect: {
+        (function(o) {
+            function f() {
+                f = console.log;
+                if (o.p++)
+                    throw "FAIL";
+                f("PASS");
+            }
+            return f;
+        })({ p: 0 })();
+    }
+    expect_stdout: "PASS"
+}
+
+shorter_without_void: {
+    options = {
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a;
+        function f(b) {
+            a = b;
+        }
+        f("foo");
+        console.log(a) || f("bar");
+        console.log(a, f("baz"));
+        console.log(a);
+    }
+    expect: {
+        var a;
+        function f(b) {
+            a = b;
+        }
+        a = "foo";
+        console.log(a) || (a = "bar");
+        console.log(a, f("baz"));
+        console.log(a);
+    }
+    expect_stdout: [
+        "foo",
+        "bar undefined",
+        "baz",
+    ]
+}
+
+issue_5120: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f() {
+            function g() {
+                f || g();
+            }
+            g();
+            return f.valueOf();
+        };
+        console.log(a() === a ? "PASS" : "FAIL");
+    }
+    expect: {
+        function a() {
+            (function g() {
+                a || g();
+            })();
+            return a.valueOf();
+        }
+        console.log(a() === a ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5140: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        A = 42;
+        function f(b) {
+            return b >> 0;
+        }
+        var a = f(42 in []);
+        console.log(f(A));
+    }
+    expect: {
+        function f(b) {
+            return b >> 0;
+        }
+        A = 42;
+        console.log(A >> 0);
+    }
+    expect_stdout: "42"
+}
+
+issue_5173_1: {
+    options = {
+        conditionals: true,
+        inline: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        function f(a, b) {
+            console.log(b);
+        }
+        f([ A = 42, [] + "" || (A = f) ]);
+    }
+    expect: {
+        function f(a, b) {
+            console.log(b);
+        }
+        f([ A = 42, [] + "" || (A = f) ]);
+    }
+    expect_stdout: "undefined"
+}
+
+issue_5173_2: {
+    options = {
+        conditionals: true,
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f(a, b) {
+            console.log(b);
+        }
+        f([ A = 42, [] + "" || (A = f) ]);
+    }
+    expect: {
+        function f(a, b) {
+            console.log(b);
+        }
+        f(A = [] + "" ? 42 : f);
+    }
+    expect_stdout: "undefined"
+}

test/compress/hoist_props.js

@@ -217,7 +217,8 @@ name_collision_1: {
         var obj_foo = 1;
         var obj_bar = 2;
         function f() {
-            var obj_foo$0 = 3,
+            var obj,
+                obj_foo$0 = 3,
                 obj_bar = 4,
                 obj_b_r = 5,
                 obj_b_r$0 = 6,
@@ -249,7 +250,8 @@ name_collision_2: {
         console.log(o.p === o.p, o["+"](4), o["-"](5), o__$0, o__$1);
     }
     expect: {
-        var o_p = 1,
+        var o,
+            o_p = 1,
             o__ = function(x) {
                 return x;
             },
@@ -283,7 +285,8 @@ name_collision_3: {
         console.log(o.p === o.p, o["+"](4), o["-"](5));
     }
     expect: {
-        var o_p = 1,
+        var o,
+            o_p = 1,
             o__ = function(x) {
                 return x;
             },
@@ -315,7 +318,7 @@ name_collision_4: {
     }
     expect: {
         console.log(function() {
-            var o_p$0 = 0, o_q = "PASS";
+            var o, o_p$0 = 0, o_q = "PASS";
             return function(o_p) {
                 if (!o_p$0) return o_p;
             }(o_q);
@@ -768,7 +771,7 @@ issue_3046: {
     expect: {
         console.log(function(a) {
             do {
-                var b_c = a++;
+                var b, b_c = a++;
             } while (b_c && a);
             return a;
         }(0));
@@ -777,6 +780,32 @@ issue_3046: {
 }
 
 issue_3071_1: {
+    options = {
+        evaluate: true,
+        hoist_props: true,
+        inline: true,
+        join_vars: true,
+        passes: 3,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var obj = {};
+            obj.one = 1;
+            obj.two = 2;
+            console.log(obj.one, obj.two);
+        })();
+    }
+    expect: {
+        console.log(1, 2);
+    }
+    expect_stdout: "1 2"
+}
+
+issue_3071_1_toplevel: {
     options = {
         evaluate: true,
         hoist_props: true,
@@ -905,7 +934,7 @@ issue_3411: {
     expect: {
         var c = 1;
         !function f() {
-            var o_p = --c && f();
+            var o, o_p = --c && f();
             +{} || console.log("PASS");
         }();
     }
@@ -1016,9 +1045,7 @@ issue_3945_1: {
     expect: {
         function f() {
             o.p;
-            var o = {
+            var o, o_q = 0;
-                q: 0,
-            };
         }
     }
 }
@@ -1037,9 +1064,7 @@ issue_3945_2: {
     }
     expect: {
         console.log(typeof o);
-        var o = {
+        var o, o_p = 0;
-            p: 0,
-        };
     }
     expect_stdout: "undefined"
 }
@@ -1094,3 +1119,60 @@ object_super: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4985: {
+    options = {
+        hoist_props: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = { p: 42 };
+        console.log(function() {
+            a;
+        }());
+    }
+    expect: {
+        var a, a_p = 42;
+        console.log(function() {
+            ({});
+        }());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_5182: {
+    options = {
+        hoist_props: true,
+        merge_vars: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var o = console;
+        log = o.log;
+        o = {
+            p: function(a) {
+                console.log(a ? "PASS" : "FAIL");
+                return a;
+            },
+        };
+        log(o.p(42));
+    }
+    expect: {
+        var o_p = console;
+        log = o_p.log;
+        o_p = function(a) {
+            console.log(a ? "PASS" : "FAIL");
+            return a;
+        };
+        log(o_p(42));
+    }
+    expect_stdout: [
+        "PASS",
+        "42",
+    ]
+}

test/compress/hoist_vars.js

@@ -135,7 +135,7 @@ issue_2295: {
     }
 }
 
-issue_4487: {
+issue_4487_1: {
     options = {
         functions: true,
         hoist_vars: true,
@@ -150,6 +150,31 @@ issue_4487: {
         };
         var b = a();
     }
+    expect: {
+        var a = function f() {
+            var f = console.log(typeof f);
+        };
+        a();
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4487_2: {
+    options = {
+        functions: true,
+        hoist_vars: true,
+        keep_fnames: true,
+        passes: 2,
+        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 f = console.log(typeof f);
@@ -159,6 +184,30 @@ issue_4487: {
     expect_stdout: "undefined"
 }
 
+issue_4487_3: {
+    options = {
+        functions: true,
+        hoist_vars: true,
+        keep_fnames: true,
+        passes: 3,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f() {
+            var f = console.log(typeof f);
+        };
+        var b = a();
+    }
+    expect: {
+        (function a() {
+            console.log(typeof void 0);
+        })();
+    }
+    expect_stdout: "undefined"
+}
+
 issue_4489: {
     options = {
         collapse_vars: true,
@@ -250,18 +299,18 @@ issue_4839: {
         unused: true,
     }
     input: {
-        var o = function(a, b) {
+        var log = console.log, o = function(a, b) {
             return b && b;
         }("foo");
         for (var k in o)
             throw "FAIL";
-        console.log("PASS");
+        log("PASS");
     }
     expect: {
-        var k, o = void 0;
+        var k, log = console.log;
-        for (k in o)
+        for (k in void 0)
             throw "FAIL";
-        console.log("PASS");
+        log("PASS");
     }
     expect_stdout: "PASS"
 }
@@ -287,8 +336,7 @@ issue_4859: {
     }
     expect: {
         (function f(a) {
-            var d = 1 / 0, d = Infinity;
+            console.log(Infinity);
-            console.log(d);
             return f;
         })();
     }
@@ -322,9 +370,7 @@ issue_4893_1: {
     expect: {
         try{
             (function f() {
-                var b;
+                null.p += 42;
-                b = null;
-                b.p += 42;
                 f;
             })();
         } catch (e) {
@@ -396,3 +442,61 @@ issue_4898: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5187: {
+    options = {
+        hoist_props: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var a = 42;
+            do {
+                var b = { 0: a++ };
+            } while (console.log(b[b ^= 0]));
+        }
+        f();
+    }
+    expect: {
+        (function() {
+            var b, a = 42;
+            do {
+                b = { 0: a++ };
+            } while (console.log(b[b ^= 0]));
+        })();
+    }
+    expect_stdout: "42"
+}
+
+issue_5195: {
+    options = {
+        hoist_props: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var a;
+            do {
+                var b = { p: a };
+            } while (console.log(b += ""));
+        }
+        f();
+    }
+    expect: {
+        (function() {
+            var a, b;
+            do {
+                b = { p: a };
+            } while (console.log(b += ""));
+        })();
+    }
+    expect_stdout: "[object Object]"
+}

test/compress/imports.js

@@ -94,13 +94,15 @@ drop_unused: {
     }
     input: {
         import a, * as b from "foo";
-        import { c, bar as d } from "baz";
+        import { c } from "bar";
-        console.log(c);
+        import { d, _ as e } from "baz";
+        console.log(d);
     }
     expect: {
         import "foo";
-        import { c as c } from "baz";
+        import "bar";
-        console.log(c);
+        import { d as d } from "baz";
+        console.log(d);
     }
 }
 

test/compress/issue-1446.js

@@ -24,7 +24,7 @@ typeof_eq_undefined: {
 typeof_eq_undefined_ie8: {
     options = {
         comparisons: true,
-        ie8: true,
+        ie: true,
         typeofs: true,
     }
     input: {

test/compress/issue-1588.js

@@ -1,9 +1,9 @@
 screw_ie8: {
     options = {
-        ie8: false,
+        ie: false,
     }
     mangle = {
-        ie8: false,
+        ie: false,
     }
     input: {
         try { throw "foo"; } catch (x) { console.log(x); }
@@ -16,10 +16,10 @@ screw_ie8: {
 
 support_ie8: {
     options = {
-        ie8: true,
+        ie: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
     }
     input: {
         try { throw "foo"; } catch (x) { console.log(x); }

test/compress/issue-1704.js

@@ -1,10 +1,10 @@
 mangle_catch: {
     options = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -22,11 +22,11 @@ mangle_catch: {
 
 mangle_catch_ie8: {
     options = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -44,11 +44,11 @@ mangle_catch_ie8: {
 
 mangle_catch_var: {
     options = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -66,11 +66,11 @@ mangle_catch_var: {
 
 mangle_catch_var_ie8: {
     options = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -88,11 +88,11 @@ mangle_catch_var_ie8: {
 
 mangle_catch_toplevel: {
     options = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -110,11 +110,11 @@ mangle_catch_toplevel: {
 
 mangle_catch_ie8_toplevel: {
     options = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -132,11 +132,11 @@ mangle_catch_ie8_toplevel: {
 
 mangle_catch_var_toplevel: {
     options = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -154,11 +154,11 @@ mangle_catch_var_toplevel: {
 
 mangle_catch_var_ie8_toplevel: {
     options = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -176,11 +176,11 @@ mangle_catch_var_ie8_toplevel: {
 
 mangle_catch_redef_1: {
     options = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -198,11 +198,11 @@ mangle_catch_redef_1: {
 
 mangle_catch_redef_1_ie8: {
     options = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -220,11 +220,11 @@ mangle_catch_redef_1_ie8: {
 
 mangle_catch_redef_1_toplevel: {
     options = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -242,11 +242,11 @@ mangle_catch_redef_1_toplevel: {
 
 mangle_catch_redef_1_ie8_toplevel: {
     options = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -264,11 +264,11 @@ mangle_catch_redef_1_ie8_toplevel: {
 
 mangle_catch_redef_2: {
     options = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -285,11 +285,11 @@ mangle_catch_redef_2: {
 
 mangle_catch_redef_2_ie8: {
     options = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -306,11 +306,11 @@ mangle_catch_redef_2_ie8: {
 
 mangle_catch_redef_2_toplevel: {
     options = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -327,11 +327,11 @@ mangle_catch_redef_2_toplevel: {
 
 mangle_catch_redef_2_ie8_toplevel: {
     options = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -348,7 +348,7 @@ mangle_catch_redef_2_ie8_toplevel: {
 
 mangle_catch_redef_3: {
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -371,7 +371,7 @@ mangle_catch_redef_3: {
 
 mangle_catch_redef_3_toplevel: {
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -394,7 +394,7 @@ mangle_catch_redef_3_toplevel: {
 
 mangle_catch_redef_3_ie8: {
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -417,7 +417,7 @@ mangle_catch_redef_3_ie8: {
 
 mangle_catch_redef_3_ie8_toplevel: {
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {

test/compress/issue-1733.js

@@ -1,6 +1,6 @@
 function_iife_catch: {
     mangle = {
-        ie8: false,
+        ie: false,
     }
     input: {
         function f(n) {
@@ -21,7 +21,7 @@ function_iife_catch: {
 
 function_iife_catch_ie8: {
     mangle = {
-        ie8: true,
+        ie: true,
     }
     input: {
         function f(n) {
@@ -42,7 +42,7 @@ function_iife_catch_ie8: {
 
 function_catch_catch: {
     mangle = {
-        ie8: false,
+        ie: false,
     }
     input: {
         var o = 0;
@@ -70,7 +70,7 @@ function_catch_catch: {
 
 function_catch_catch_ie8: {
     mangle = {
-        ie8: true,
+        ie: true,
     }
     input: {
         var o = 0;

test/compress/join_vars.js

@@ -489,6 +489,116 @@ join_object_assignments_regex: {
     expect_stdout: "1"
 }
 
+chained_assignments: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        var a, b = a = {};
+        b.p = "PASS";
+        console.log(a.p);
+    }
+    expect: {
+        var a, b = a = {
+            p: "PASS",
+        };
+        console.log(a.p);
+    }
+    expect_stdout: "PASS"
+}
+
+folded_assignments_1: {
+    options = {
+        evaluate: true,
+        join_vars: true,
+    }
+    input: {
+        var a = {};
+        a[a.PASS = 42] = "PASS";
+        console.log(a[42], a.PASS);
+    }
+    expect: {
+        var a = {
+            PASS: 42,
+            42: "PASS",
+        };
+        console.log(a[42], a.PASS);
+    }
+    expect_stdout: "PASS 42"
+}
+
+folded_assignments_2: {
+    options = {
+        evaluate: true,
+        join_vars: true,
+    }
+    input: {
+        "use strict";
+        var a = {};
+        a[42] = "FAIL";
+        a[a.PASS = 42] = "PASS";
+        console.log(a[42], a.PASS);
+    }
+    expect: {
+        "use strict";
+        var a = {
+            42: "FAIL",
+            PASS: 42,
+        };
+        a[42] = "PASS";
+        console.log(a[42], a.PASS);
+    }
+    expect_stdout: "PASS 42"
+}
+
+inlined_assignments: {
+    options = {
+        join_vars: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        (a = {}).p = "PASS";
+        console.log(a.p);
+    }
+    expect: {
+        var a = {
+            p: "PASS",
+        };
+        console.log(a.p);
+    }
+    expect_stdout: "PASS"
+}
+
+typescript_enum: {
+    rename = true
+    options = {
+        assignments: true,
+        collapse_vars: true,
+        evaluate: true,
+        hoist_props: true,
+        inline: true,
+        join_vars: true,
+        passes: 4,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var Enum;
+        (function (Enum) {
+            Enum[Enum.PASS = 42] = "PASS";
+        })(Enum || (Enum = {}));
+        console.log(Enum[42], Enum.PASS);
+    }
+    expect: {
+        console.log("PASS", 42);
+    }
+    expect_stdout: "PASS 42"
+}
+
 issue_2816: {
     options = {
         join_vars: true,
@@ -1015,7 +1125,7 @@ issue_3856: {
         console.log(function() {
             (function() {
                 var a, b;
-                if (a) return !!a;
+                if (a) return a, 1;
                 for (a = 0; !console;);
                 return 0;
             })();
@@ -1183,3 +1293,26 @@ assign_sequence_var: {
         "1 2 3",
     ]
 }
+
+issue_5175: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        function log(f) {
+            console.log(f(), A.p);
+        }
+        log(function() {
+            return (A = {}).p = "PASS";
+        });
+    }
+    expect: {
+        function log(f) {
+            console.log(f(), A.p);
+        }
+        log(function() {
+            return (A = {}).p = "PASS";
+        });
+    }
+    expect_stdout: "PASS PASS"
+}

test/compress/keep_fargs.js

@@ -117,6 +117,7 @@ issue_1858: {
         collapse_vars: true,
         keep_fargs: false,
         pure_getters: true,
+        reduce_vars: true,
         unused: true,
     }
     input: {
@@ -950,7 +951,7 @@ function_name_mangle_ie8: {
         unused: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -1157,8 +1158,8 @@ replace_all_var_scope: {
         var a = 100, b = 10;
         (function(r, a) {
             switch (~a) {
-            case (b += a):
+              case (b += a):
-            case a++:
+              case a++:
             }
         })(--b, a);
         console.log(a, b);
@@ -1167,8 +1168,8 @@ replace_all_var_scope: {
         var a = 100, b = 10;
         (function(c) {
             switch (~a) {
-            case (b += a):
+              case (b += a):
-            case c++:
+              case c++:
             }
         })((--b, a));
         console.log(a, b);

test/compress/labels.js

@@ -83,8 +83,9 @@ labels_5: {
         conditionals: true,
         dead_code: true,
         if_return: true,
+        unused: true,
     }
-    // should keep the break-s in the following
+    // should keep `break`s below
     input: {
         while (foo) {
             if (bar) break;
@@ -100,8 +101,8 @@ labels_5: {
             if (bar) break;
             console.log("foo");
         }
-        out: while (foo) {
+        while (foo) {
-            if (bar) break out;
+            if (bar) break;
             console.log("foo");
         }
     }
@@ -189,23 +190,22 @@ labels_10: {
         conditionals: true,
         dead_code: true,
         if_return: true,
+        unused: true,
     }
     input: {
-        out: while (foo) {
+        out: while (42) {
-            x();
+            console.log("PASS");
-            y();
             break out;
-            z();
+            console.log("FAIL");
-            k();
         }
     };
     expect: {
-        out: while (foo) {
+        while (42) {
-            x();
+            console.log("PASS");
-            y();
+            break;
-            break out;
         }
     }
+    expect_stdout: "PASS"
 }
 
 issue_4466_1: {

test/compress/let.js

@@ -20,6 +20,39 @@ retain_block: {
     node_version: ">=4"
 }
 
+retain_assignment: {
+    options = {
+        dead_code: true,
+        reduce_vars: true,
+    }
+    input: {
+        "use strict";
+        function f() {
+            return a = 0;
+            let a;
+        }
+        try {
+            f();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        function f() {
+            return a = 0;
+            let a;
+        }
+        try {
+            f();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 retain_catch: {
     options = {
         dead_code: true,
@@ -461,6 +494,41 @@ reduce_vars_3: {
     node_version: ">=4"
 }
 
+reduce_lambda: {
+    options = {
+        evaluate: true,
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        let f = function() {
+            console.log(a, b);
+        };
+        let a = "foo", b = 42;
+        f();
+        b = "bar";
+        f();
+    }
+    expect: {
+        "use strict";
+        function f() {
+            console.log("foo", b);
+        }
+        let b = 42;
+        f();
+        b = "bar";
+        f();
+    }
+    expect_stdout: [
+        "foo 42",
+        "foo bar",
+    ]
+    node_version: ">=4"
+}
+
 hoist_props: {
     options = {
         hoist_props: true,
@@ -536,6 +604,38 @@ loop_block_2: {
     node_version: ">=4"
 }
 
+do_break: {
+    options = {
+        loops: true,
+    }
+    input: {
+        "use strict";
+        try {
+            do {
+                if (a)
+                    break;
+                let a;
+            } while (!console);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            do {
+                if (a)
+                    break;
+                let a;
+            } while (!console);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 do_continue: {
     options = {
         loops: true,
@@ -596,6 +696,82 @@ dead_block_after_return: {
     node_version: ">=4"
 }
 
+if_return_1: {
+    options = {
+        if_return: true,
+    }
+    input: {
+        "use strict";
+        function f(a) {
+            function g() {
+                return b = "PASS";
+            }
+            if (a)
+                return g();
+            let b;
+            return g();
+        };
+        console.log(f());
+    }
+    expect: {
+        "use strict";
+        function f(a) {
+            function g() {
+                return b = "PASS";
+            }
+            if (a)
+                return g();
+            let b;
+            return g();
+        };
+        console.log(f());
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+if_return_2: {
+    options = {
+        if_return: true,
+    }
+    input: {
+        "use strict";
+        function f(a) {
+            function g() {
+                return b = "FAIL";
+            }
+            if (a)
+                return g();
+            let b;
+            return g();
+        };
+        try {
+            console.log(f(42));
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        function f(a) {
+            function g() {
+                return b = "FAIL";
+            }
+            if (a)
+                return g();
+            let b;
+            return g();
+        };
+        try {
+            console.log(f(42));
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 do_if_continue_1: {
     options = {
         if_return: true,
@@ -897,6 +1073,7 @@ issue_4210: {
 issue_4212_1: {
     options = {
         dead_code: true,
+        reduce_vars: true,
     }
     input: {
         "use strict";
@@ -987,7 +1164,7 @@ issue_4225: {
 
 issue_4229: {
     options = {
-        ie8: true,
+        ie: true,
         side_effects: true,
     }
     input: {
@@ -1018,7 +1195,7 @@ issue_4229: {
 
 issue_4231: {
     options = {
-        ie8: true,
+        ie: true,
         side_effects: true,
     }
     input: {
@@ -1387,7 +1564,7 @@ issue_4438: {
 
 issue_4531_1: {
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -1413,11 +1590,11 @@ issue_4531_1: {
 issue_4531_2: {
     options = {
         evaluate: true,
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -1546,3 +1723,27 @@ issue_4848: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4985: {
+    options = {
+        hoist_props: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        let a = { p: 42 };
+        console.log(function() {
+            a;
+        }());
+    }
+    expect: {
+        "use strict";
+        let a = { p: 42 };
+        console.log(function() {
+            a;
+        }());
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}

test/compress/loops.js

@@ -193,9 +193,9 @@ evaluate: {
         } while (false);
     }
     expect: {
-        for(;;)
+        for (;;)
             a();
-        for(;;)
+        for (;;)
             c();
         d();
     }
@@ -265,7 +265,7 @@ issue_1532_2: {
 issue_186: {
     beautify = {
         beautify: false,
-        ie8: false,
+        ie: false,
     }
     input: {
         var x = 3;
@@ -284,7 +284,7 @@ issue_186: {
 issue_186_ie8: {
     beautify = {
         beautify: false,
-        ie8: true,
+        ie: true,
     }
     input: {
         var x = 3;
@@ -303,7 +303,7 @@ issue_186_ie8: {
 issue_186_beautify: {
     beautify = {
         beautify: true,
-        ie8: false,
+        ie: false,
     }
     input: {
         var x = 3;
@@ -330,7 +330,7 @@ issue_186_beautify: {
 issue_186_beautify_ie8: {
     beautify = {
         beautify: true,
-        ie8: true,
+        ie: true,
     }
     input: {
         var x = 3;
@@ -360,7 +360,7 @@ issue_186_braces: {
     beautify = {
         beautify: false,
         braces: true,
-        ie8: false,
+        ie: false,
     }
     input: {
         var x = 3;
@@ -380,7 +380,7 @@ issue_186_braces_ie8: {
     beautify = {
         beautify: false,
         braces: true,
-        ie8: true,
+        ie: true,
     }
     input: {
         var x = 3;
@@ -400,7 +400,7 @@ issue_186_beautify_braces: {
     beautify = {
         beautify: true,
         braces: true,
-        ie8: false,
+        ie: false,
     }
     input: {
         var x = 3;
@@ -432,7 +432,7 @@ issue_186_beautify_braces_ie8: {
     beautify = {
         beautify: true,
         braces: true,
-        ie8: true,
+        ie: true,
     }
     input: {
         var x = 3;

test/compress/merge_vars.js

@@ -359,7 +359,7 @@ issue_4107: {
 
 issue_4109: {
     options = {
-        ie8: true,
+        ie: true,
         merge_vars: true,
         toplevel: true,
     }
@@ -476,9 +476,9 @@ issue_4112: {
             try {
                 throw 42;
             } catch (e) {
-                var a = e;
+                var o = e;
-                for (e in a);
+                for (e in o);
-                a = function() {};
+                function a() {}
                 console.log(typeof a);
                 return a;
             }
@@ -2735,8 +2735,7 @@ issue_4135: {
         0;
         a++;
         if (!a)
-            c = (a++, c = 0, void (c && c.p));
+            var c = void a++;
-        var c;
         console.log(a, -1, c);
     }
     expect_stdout: "1 -1 undefined"
@@ -3075,7 +3074,7 @@ issue_4237_2: {
         console.log(function(a) {
             do {
                 switch (0) {
-                  case 0:
+                  default:
                     var b = a++;
                     if (b)
                         return "FAIL";
@@ -3301,3 +3300,137 @@ issue_4761: {
     }
     expect_stdout: "undefined"
 }
+
+issue_4956_1: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b;
+        function f(c) {
+            switch (c) {
+              case 0:
+                a = { p: 42 };
+
+              case 1:
+                b = a.p;
+                console.log(b);
+            }
+        }
+        f(0);
+        f(1);
+    }
+    expect: {
+        var a, b;
+        function f(c) {
+            switch (c) {
+              case 0:
+                a = { p: 42 };
+
+              case 1:
+                b = a.p;
+                console.log(b);
+            }
+        }
+        f(0);
+        f(1);
+    }
+    expect_stdout: [
+        "42",
+        "42",
+    ]
+}
+
+issue_4956_2: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b;
+        function f(c) {
+            if (0 == c) {
+                console;
+                a = { p: 42 };
+            }
+            b = a.p;
+            if (1 == c)
+                console.log(b);
+        }
+        f(0);
+        f(1);
+    }
+    expect: {
+        var a, b;
+        function f(c) {
+            if (0 == c) {
+                console;
+                a = { p: 42 };
+            }
+            b = a.p;
+            if (1 == c)
+                console.log(b);
+        }
+        f(0);
+        f(1);
+    }
+    expect_stdout: "42"
+}
+
+issue_5182: {
+    options = {
+        arrows: true,
+        collapse_vars: true,
+        evaluate: true,
+        hoist_props: true,
+        inline: true,
+        merge_vars: true,
+        passes: 4,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        try {
+            var con = console;
+        } catch (x) {}
+        global.log = con.log;
+        var jump = function(x) {
+            console.log("JUMP:", x * 10);
+            return x + x;
+        };
+        var jump2 = jump;
+        var run = function(x) {
+            console.log("RUN:", x * -10);
+            return x * x;
+        };
+        var run2 = run;
+        var bar = (x, y) => {
+            console.log("BAR:", x + y);
+            return x - y;
+        };
+        var bar2 = bar;
+        var obj = {
+            foo: bar2,
+            go: run2,
+            not_used: jump2,
+        };
+        console.log(obj.foo(1, 2), global.log("PASS"));
+    }
+    expect: {
+        try {
+            var con = console;
+        } catch (x) {}
+        global.log = con.log,
+        console.log((console.log("BAR:", 3), -1), global.log("PASS"));
+    }
+    expect_stdout: [
+        "BAR: 3",
+        "PASS",
+        "-1 undefined",
+    ]
+    node_version: ">=4"
+}

test/compress/nullish.js

@@ -110,10 +110,162 @@ conditional_assignment_4: {
     node_version: ">=14"
 }
 
+de_morgan_1: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        function f(a) {
+            return a ?? a;
+        }
+        console.log(f(null), f(42));
+    }
+    expect: {
+        function f(a) {
+            return a;
+        }
+        console.log(f(null), f(42));
+    }
+    expect_stdout: "null 42"
+    node_version: ">=14"
+}
+
+de_morgan_2a: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        evaluate: true,
+    }
+    input: {
+        function f(a, b) {
+            return a || (a ?? b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a || (a ?? b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "undefined {}",
+        "42 42",
+    ]
+    node_version: ">=14"
+}
+
+de_morgan_2b: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        function f(a, b) {
+            return a && (a ?? b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "null null",
+        "42 42",
+    ]
+    node_version: ">=14"
+}
+
+de_morgan_2c: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        side_effects: true,
+    }
+    input: {
+        function f(a, b) {
+            return a ?? (a || b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a ?? b;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "undefined {}",
+        "42 42",
+    ]
+    node_version: ">=14"
+}
+
+de_morgan_2d: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        function f(a, b) {
+            return a ?? (a && b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "null null",
+        "42 42",
+    ]
+    node_version: ">=14"
+}
+
+de_morgan_2e: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        function f(a, b) {
+            return a ?? (a ?? b);
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect: {
+        function f(a, b) {
+            return a ?? b;
+        }
+        console.log(f(null), f(null, {}));
+        console.log(f(42), f(42, {}));
+    }
+    expect_stdout: [
+        "undefined {}",
+        "42 42",
+    ]
+    node_version: ">=14"
+}
+
 issue_4679: {
     options = {
         comparisons: true,
-        ie8: true,
+        ie: true,
     }
     input: {
         var a;

test/compress/objects.js

@@ -521,3 +521,25 @@ issue_4415: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_5213: {
+    options = {
+        objects: true,
+    }
+    input: {
+        var a = "FAIL";
+        console.log({
+            p: a = "PASS",
+            0: a,
+            p: null,
+        }[0]);
+    }
+    expect: {
+        var a = "FAIL";
+        console.log({
+            p: (a = "PASS", null),
+            0: a,
+        }[0]);
+    }
+    expect_stdout: "PASS"
+}

test/compress/optional-chains.js

@@ -43,6 +43,68 @@ ternary_decimal: {
     expect_stdout: "PASS"
 }
 
+assign_parentheses_call: {
+    input: {
+        var o = {};
+        ((() => o)?.()).p = "PASS";
+        console.log(o.p);
+    }
+    expect_exact: 'var o={};((()=>o)?.()).p="PASS";console.log(o.p);'
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+assign_parentheses_dot: {
+    input: {
+        (console?.log).name.p = console.log("PASS");
+    }
+    expect_exact: '(console?.log).name.p=console.log("PASS");'
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+assign_no_parentheses: {
+    input: {
+        console[console.log?.("PASS")] = 42;
+    }
+    expect_exact: 'console[console.log?.("PASS")]=42;'
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+call_parentheses: {
+    input: {
+        (function(o) {
+            console.log(o.f("FAIL"), (o.f)("FAIL"), (0, o.f)(42));
+            console.log(o?.f("FAIL"), (o?.f)("FAIL"), (0, o?.f)(42));
+        })({
+            a: "PASS",
+            f(b) {
+                return this.a || b;
+            },
+        });
+    }
+    expect_exact: '(function(o){console.log(o.f("FAIL"),o.f("FAIL"),(0,o.f)(42));console.log(o?.f("FAIL"),(o?.f)("FAIL"),(0,o?.f)(42))})({a:"PASS",f(b){return this.a||b}});'
+    expect_stdout: [
+        "PASS PASS 42",
+        "PASS PASS 42",
+    ]
+    node_version: ">=14"
+}
+
+unary_parentheses: {
+    input: {
+        var o = { p: 41 };
+        (function() {
+            return o;
+        }?.()).p++;
+        console.log(o.p);
+    }
+    expect_exact: "var o={p:41};(function(){return o}?.()).p++;console.log(o.p);"
+    expect_stdout: "42"
+    node_version: ">=14"
+}
+
 collapse_vars_1: {
     options = {
         collapse_vars: true,
@@ -195,6 +257,99 @@ trim_2: {
     node_version: ">=14"
 }
 
+trim_dot_call_1: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+    }
+    input: {
+        console.log(null?.f());
+    }
+    expect: {
+        console.log(void 0);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+trim_dot_call_2: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+        unsafe: true,
+    }
+    input: {
+        try {
+            (null?.p)();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            (void 0)();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+trim_dot_call_3: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+        unsafe: true,
+    }
+    input: {
+        try {
+            ({ p: null })?.p();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            null();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+trim_dot_sub: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+    }
+    input: {
+        console.log(null?.p[42]);
+    }
+    expect: {
+        console.log(void 0);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+trim_sub_call_call: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+    }
+    input: {
+        console.log(null?.[42]()());
+    }
+    expect: {
+        console.log(void 0);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
 issue_4906: {
     options = {
         toplevel: true,
@@ -211,3 +366,103 @@ issue_4906: {
     expect_stdout: "PASS"
     node_version: ">=14"
 }
+
+issue_4928: {
+    options = {
+        ie: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = a?.[function f() {
+            f(a);
+        }];
+        console.log(typeof f);
+    }
+    expect: {
+        var a = a?.[function f() {
+            f(a);
+        }];
+        console.log(typeof f);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+issue_4947_1: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        console.log(console.foo ? 42..p : console.bar?.p);
+    }
+    expect: {
+        console.log(console.foo ? 42..p : console.bar?.p);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+issue_4947_2: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        var log = console.log, fail;
+        log("PASS") ? log(42) : fail?.(42);
+    }
+    expect: {
+        var log = console.log, fail;
+        log("PASS") ? log(42) : fail?.(42);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+issue_5039: {
+    options = {
+        ie: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = a?.[function f() {
+            f;
+            a;
+        }];
+        console.log("PASS");
+    }
+    expect: {
+        (function f() {});
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+issue_5091: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a) {
+            var b = a.p;
+            var c;
+            b?.[c = "FAIL 2"];
+            return b || c;
+        }
+        console.log(f("FAIL 1") || "PASS");
+    }
+    expect: {
+        function f(b) {
+            var b = b.p;
+            var c;
+            b?.[c = "FAIL 2"];
+            return b || c;
+        }
+        console.log(f("FAIL 1") || "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}

test/compress/properties.js

@@ -17,7 +17,7 @@ dot_properties: {
         properties: true,
     }
     beautify = {
-        ie8: true,
+        ie: true,
     }
     input: {
         a["foo"] = "bar";
@@ -43,7 +43,7 @@ dot_properties_es5: {
         properties: true,
     }
     beautify = {
-        ie8: false,
+        ie: false,
     }
     input: {
         a["foo"] = "bar";
@@ -1463,3 +1463,118 @@ issue_4888: {
     }
     expect_stdout: "object"
 }
+
+issue_5093: {
+    beautify = {
+        keep_quoted_props: true,
+    }
+    input: {
+        console.log({
+            a: true,
+            '42': "PASS",
+            "null": [],
+        }[6 * 7]);
+    }
+    expect_exact: 'console.log({a:true,"42":"PASS","null":[]}[6*7]);'
+    expect_stdout: "PASS"
+}
+
+issue_5093_quote_keys: {
+    beautify = {
+        keep_quoted_props: true,
+        quote_keys: true,
+    }
+    input: {
+        console.log({
+            a: true,
+            '42': "PASS",
+            "null": [],
+        }[6 * 7]);
+    }
+    expect_exact: 'console.log({"a":true,"42":"PASS","null":[]}[6*7]);'
+    expect_stdout: "PASS"
+}
+
+issue_5093_quote_style: {
+    beautify = {
+        keep_quoted_props: true,
+        quote_style: 3,
+    }
+    input: {
+        console.log({
+            a: true,
+            '42': "PASS",
+            "null": [],
+        }[6 * 7]);
+    }
+    expect_exact: 'console.log({a:true,\'42\':"PASS","null":[]}[6*7]);'
+    expect_stdout: "PASS"
+}
+
+object_methods: {
+    options = {
+        properties: true,
+    }
+    input: {
+        ({
+            p() {
+                console.log("FAIL 1");
+            },
+            *q() {
+                console.log("FAIL 2");
+            },
+            async r() {
+                console.log("FAIL 3");
+            },
+            async *s() {
+                console.log("PASS");
+            },
+        }).s().next();
+    }
+    expect: {
+        [
+            () => {
+                console.log("FAIL 1");
+            },
+            function*() {
+                console.log("FAIL 2");
+            },
+            async () => {
+                console.log("FAIL 3");
+            },
+            async function*() {
+                console.log("PASS");
+            },
+        ][3]().next();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=10"
+}
+
+issue_5177: {
+    options = {
+        properties: true,
+    }
+    input: {
+        var a = "FAIL";
+        var o = { a: "PASS" };
+        o.p = {
+            q() {
+                return this.a;
+            },
+        }.q;
+        console.log(o.p());
+    }
+    expect: {
+        var a = "FAIL";
+        var o = { a: "PASS" };
+        o.p = {
+            q() {
+                return this.a;
+            },
+        }.q;
+        console.log(o.p());
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}

test/compress/pure_getters.js

@@ -1320,6 +1320,7 @@ issue_2878: {
 
 issue_3427: {
     options = {
+        assignments: true,
         evaluate: true,
         inline: true,
         pure_getters: "strict",
@@ -1638,3 +1639,49 @@ nested_property_assignments_3: {
     }
     expect_stdout: "PASS"
 }
+
+nested_property_assignments_4: {
+    options = {
+        pure_getters: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var n, o = { p: { q: { r: "PASS" } } };
+        (n = o.p).r = n.q.r;
+        console.log(o.p.r);
+    }
+    expect: {
+        var n, o = { p: { q: { r: "PASS" } } };
+        (n = o.p).r = n.q.r;
+        console.log(o.p.r);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4939: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        ({
+            __proto__: {
+                get p() {
+                    console.log("PASS");
+                },
+            },
+        }).p;
+    }
+    expect: {
+        ({
+            __proto__: {
+                get p() {
+                    console.log("PASS");
+                },
+            },
+        }).p;
+    }
+    expect_stdout: "PASS"
+}

test/compress/reduce_vars.js

@@ -1292,6 +1292,7 @@ toplevel_on_loops_3: {
         loops: true,
         reduce_funcs: true,
         reduce_vars: true,
+        side_effects: true,
         toplevel: true,
         unused: true,
     }
@@ -2071,72 +2072,6 @@ issue_1670_2: {
 }
 
 issue_1670_3: {
-    options = {
-        comparisons: true,
-        conditionals: true,
-        dead_code: true,
-        evaluate: true,
-        reduce_funcs: true,
-        reduce_vars: true,
-        side_effects: true,
-        switches: true,
-        typeofs: true,
-        unused: true,
-    }
-    input: {
-        (function f() {
-            switch (1) {
-              case 0:
-                var a = true;
-                break;
-              case 1:
-                if (typeof a === "undefined") console.log("PASS");
-                else console.log("FAIL");
-            }
-        })();
-    }
-    expect: {
-        (function() {
-            var a;
-            void 0 === a ? console.log("PASS") : console.log("FAIL");
-        })();
-    }
-    expect_stdout: "PASS"
-}
-
-issue_1670_4: {
-    options = {
-        conditionals: true,
-        dead_code: true,
-        evaluate: true,
-        passes: 2,
-        reduce_funcs: true,
-        reduce_vars: true,
-        side_effects: true,
-        switches: true,
-        unused: true,
-    }
-    input: {
-        (function f() {
-            switch (1) {
-              case 0:
-                var a = true;
-                break;
-              case 1:
-                if (typeof a === "undefined") console.log("PASS");
-                else console.log("FAIL");
-            }
-        })();
-    }
-    expect: {
-        (function() {
-            console.log("PASS");
-        })();
-    }
-    expect_stdout: "PASS"
-}
-
-issue_1670_5: {
     options = {
         conditionals: true,
         dead_code: true,
@@ -2168,7 +2103,7 @@ issue_1670_5: {
     expect_stdout: "1"
 }
 
-issue_1670_6: {
+issue_1670_4: {
     options = {
         conditionals: true,
         dead_code: true,
@@ -3158,7 +3093,7 @@ accessor_1: {
                 a = 2;
                 return a;
             },
-            b: 1
+            b: 1,
         }.b, a);
     }
     expect: {
@@ -3168,7 +3103,7 @@ accessor_1: {
                 a = 2;
                 return a;
             },
-            b: 1
+            b: 1,
         }.b, a);
     }
     expect_stdout: "1 1"
@@ -3188,7 +3123,7 @@ accessor_2: {
         var B = {
             get c() {
                 console.log(A);
-            }
+            },
         };
         B.c;
     }
@@ -3196,7 +3131,7 @@ accessor_2: {
         ({
             get c() {
                 console.log(1);
-            }
+            },
         }).c;
     }
     expect_stdout: "1"
@@ -3242,7 +3177,7 @@ obj_var_1: {
         var obj = {
             bar: function() {
                 return C + C;
-            }
+            },
         };
         console.log(obj.bar());
     }
@@ -3250,7 +3185,7 @@ obj_var_1: {
         console.log({
             bar: function() {
                 return 2;
-            }
+            },
         }.bar());
     }
     expect_stdout: "2"
@@ -3274,7 +3209,7 @@ obj_var_2: {
         var obj = {
             bar: function() {
                 return C + C;
-            }
+            },
         };
         console.log(obj.bar());
     }
@@ -4488,6 +4423,7 @@ perf_2: {
 
 perf_3: {
     options = {
+        passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
         toplevel: true,
@@ -4496,10 +4432,10 @@ perf_3: {
     input: {
         var foo = function(x, y, z) {
             return x < y ? x * y + z : x * z - y;
-        }
+        };
         var indirect_foo = function(x, y, z) {
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4528,10 +4464,10 @@ perf_4: {
     input: {
         var foo = function(x, y, z) {
             return x < y ? x * y + z : x * z - y;
-        }
+        };
         var indirect_foo = function(x, y, z) {
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4540,10 +4476,10 @@ perf_4: {
     expect: {
         var foo = function(x, y, z) {
             return x < y ? x * y + z : x * z - y;
-        }
+        };
         var indirect_foo = function(x, y, z) {
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4632,9 +4568,9 @@ perf_7: {
         var indirect_foo = function(x, y, z) {
             var foo = function(x, y, z) {
                 return x < y ? x * y + z : x * z - y;
-            }
+            };
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4664,9 +4600,9 @@ perf_8: {
         var indirect_foo = function(x, y, z) {
             var foo = function(x, y, z) {
                 return x < y ? x * y + z : x * z - y;
-            }
+            };
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4677,7 +4613,7 @@ perf_8: {
             return function(x, y, z) {
                 return x < y ? x * y + z : x * z - y;
             }(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -7384,6 +7320,64 @@ local_assignment_loop: {
     expect_stdout: "PASS"
 }
 
+local_assignment_modified: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a;
+        (a = a || {}).p = 42;
+        console.log(a.p);
+    }
+    expect: {
+        var a;
+        (a = {}).p = 42;
+        console.log(a.p);
+    }
+    expect_stdout: "42"
+}
+
+local_declaration: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a;
+        a || console.log(a = "PASS");
+    }
+    expect: {
+        var a;
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+local_definition_modified: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a = a || {};
+        a.p = 42;
+        console.log(a.p);
+    }
+    expect: {
+        var a = {};
+        a.p = 42;
+        console.log(a.p);
+    }
+    expect_stdout: "42"
+}
+
 issue_3957_1: {
     options = {
         evaluate: true,
@@ -7499,6 +7493,7 @@ issue_4030: {
         collapse_vars: true,
         evaluate: true,
         reduce_vars: true,
+        side_effects: true,
         toplevel: true,
         unused: true,
     }
@@ -7631,3 +7626,208 @@ issue_4568: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4937: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            while (console.log("PASS"));
+        }
+        do {
+            function g() {
+                f();
+            }
+        } while (!g);
+        f();
+    }
+    expect: {
+        function f() {
+            while (console.log("PASS"));
+        }
+        do {
+            function g() {
+                f();
+            }
+        } while (!g);
+        f();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4943_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b = 1;
+        (function f() {
+            a = "foo";
+            b-- && f();
+            console.log(a);
+            a = "bar";
+        })();
+    }
+    expect: {
+        var a, b = 1;
+        (function f() {
+            a = "foo";
+            b-- && f();
+            console.log(a);
+            a = "bar";
+        })();
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_4943_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b = 1;
+        (function f() {
+            a = "foo";
+            b-- && f();
+            console.log(a);
+            a = "bar";
+        })();
+    }
+    expect: {
+        var a, b = 1;
+        (function f() {
+            a = "foo";
+            b-- && f();
+            console.log(a);
+            a = "bar";
+        })();
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_4949: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function f(a) {
+            a = 0;
+            console.log(a++, arguments[0]);
+        })(0);
+    }
+    expect: {
+        (function(a) {
+            a = 0;
+            console.log(a++, arguments[0]);
+        })(0);
+    }
+    expect_stdout: "0 1"
+}
+
+issue_5048: {
+    options = {
+        reduce_funcs: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            var a = function() {
+                return a + 42;
+            };
+        }());
+    }
+    expect: {
+        console.log(function() {}());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_5050: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        function f() {
+            console.log(a);
+        }
+        this;
+        var a = 1;
+        f(console.log(2), f(), a = 3);
+    }
+    expect: {
+        function f() {
+            console.log(a);
+        }
+        this;
+        var a = 1;
+        f(console.log(2), f(), a = 3);
+    }
+    expect_stdout: [
+        "2",
+        "1",
+        "3",
+    ]
+}
+
+issue_5055_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "PASS";
+        function f() {
+            console.log(a || "FAIL");
+        }
+        f(0 && (a = 0)(f(this)));
+    }
+    expect: {
+        var a = "PASS";
+        function f() {
+            console.log(a || "FAIL");
+        }
+        f(0);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5055_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        function f() {
+            console.log(a || "FAIL");
+        }
+        f(0 && (a = 0)(f(this)));
+    }
+    expect: {
+        var a = "PASS";
+        function f() {
+            console.log(a || "FAIL");
+        }
+        f(0 && (a = 0)(f()));
+    }
+    expect_stdout: "PASS"
+}

test/compress/rename.js

@@ -1,11 +1,11 @@
 mangle_catch: {
     rename = true
     options = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -24,11 +24,11 @@ mangle_catch: {
 mangle_catch_ie8: {
     rename = true
     options = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -47,11 +47,11 @@ mangle_catch_ie8: {
 mangle_catch_var: {
     rename = true
     options = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -70,11 +70,11 @@ mangle_catch_var: {
 mangle_catch_var_ie8: {
     rename = true
     options = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -93,11 +93,11 @@ mangle_catch_var_ie8: {
 mangle_catch_toplevel: {
     rename = true
     options = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -116,11 +116,11 @@ mangle_catch_toplevel: {
 mangle_catch_ie8_toplevel: {
     rename = true
     options = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -139,11 +139,11 @@ mangle_catch_ie8_toplevel: {
 mangle_catch_var_toplevel: {
     rename = true
     options = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -162,11 +162,11 @@ mangle_catch_var_toplevel: {
 mangle_catch_var_ie8_toplevel: {
     rename = true
     options = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -185,11 +185,11 @@ mangle_catch_var_ie8_toplevel: {
 mangle_catch_redef_1: {
     rename = true
     options = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -208,11 +208,11 @@ mangle_catch_redef_1: {
 mangle_catch_redef_1_ie8: {
     rename = true
     options = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -231,11 +231,11 @@ mangle_catch_redef_1_ie8: {
 mangle_catch_redef_1_toplevel: {
     rename = true
     options = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -254,11 +254,11 @@ mangle_catch_redef_1_toplevel: {
 mangle_catch_redef_1_ie8_toplevel: {
     rename = true
     options = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -277,11 +277,11 @@ mangle_catch_redef_1_ie8_toplevel: {
 mangle_catch_redef_2: {
     rename = true
     options = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -299,11 +299,11 @@ mangle_catch_redef_2: {
 mangle_catch_redef_2_ie8: {
     rename = true
     options = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -321,11 +321,11 @@ mangle_catch_redef_2_ie8: {
 mangle_catch_redef_2_toplevel: {
     rename = true
     options = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -343,11 +343,11 @@ mangle_catch_redef_2_toplevel: {
 mangle_catch_redef_2_ie8_toplevel: {
     rename = true
     options = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -365,7 +365,7 @@ mangle_catch_redef_2_ie8_toplevel: {
 issue_2120_1: {
     rename = true
     mangle = {
-        ie8: false,
+        ie: false,
     }
     input: {
         "aaaaaaaa";
@@ -401,7 +401,7 @@ issue_2120_1: {
 issue_2120_2: {
     rename = true
     mangle = {
-        ie8: true,
+        ie: true,
     }
     input: {
         "aaaaaaaa";
@@ -436,7 +436,7 @@ issue_2120_2: {
 function_iife_catch: {
     rename = true
     mangle = {
-        ie8: false,
+        ie: false,
     }
     input: {
         function f(n) {
@@ -458,7 +458,7 @@ function_iife_catch: {
 function_iife_catch_ie8: {
     rename = true
     mangle = {
-        ie8: true,
+        ie: true,
     }
     input: {
         function f(n) {
@@ -480,7 +480,7 @@ function_iife_catch_ie8: {
 function_catch_catch: {
     rename = true
     mangle = {
-        ie8: false,
+        ie: false,
     }
     input: {
         var o = 0;
@@ -509,7 +509,7 @@ function_catch_catch: {
 function_catch_catch_ie8: {
     rename = true
     mangle = {
-        ie8: true,
+        ie: true,
     }
     input: {
         var o = 0;
@@ -538,12 +538,12 @@ function_catch_catch_ie8: {
 function_do_catch_ie8: {
     rename = true
     options = {
-        ie8: true,
+        ie: true,
         side_effects: true,
         unused: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -615,7 +615,7 @@ function_do_catch_ie8: {
 issue_3480: {
     rename = true,
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: false,
     }
     input: {
@@ -647,7 +647,7 @@ issue_3480: {
 issue_3480_ie8: {
     rename = true,
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: false,
     }
     input: {
@@ -679,7 +679,7 @@ issue_3480_ie8: {
 issue_3480_toplevel: {
     rename = true,
     mangle = {
-        ie8: false,
+        ie: false,
         toplevel: true,
     }
     input: {
@@ -711,7 +711,7 @@ issue_3480_toplevel: {
 issue_3480_ie8_toplevel: {
     rename = true,
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {

test/compress/rests.js

@@ -51,7 +51,7 @@ arrow_destructured_object_1: {
     }
     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"
+    node_version: ">=8.3.0"
 }
 
 arrow_destructured_object_2: {
@@ -62,7 +62,7 @@ arrow_destructured_object_2: {
     }
     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"
+    node_version: ">=8.3.0"
 }
 
 arrow_destructured_object_3: {
@@ -79,7 +79,7 @@ arrow_destructured_object_3: {
         "2 S",
         "3 S",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 funarg_1: {
@@ -131,7 +131,7 @@ destructured_object_1: {
     }
     expect_exact: 'var{...a}=["FAIL","PASS",42];console.log(a[1],a[2]);'
     expect_stdout: "PASS 42"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 destructured_object_2: {
@@ -141,7 +141,7 @@ destructured_object_2: {
     }
     expect_exact: 'var{0:a,...b}=["FAIL","PASS",42];console.log(b[1],b[2]);'
     expect_stdout: "PASS 42"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 drop_fargs: {
@@ -231,7 +231,7 @@ reduce_destructured_object: {
         console.log(a[0]);
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 retain_destructured_array: {
@@ -244,7 +244,7 @@ retain_destructured_array: {
         console.log.apply(console, b);
     }
     expect: {
-        var [ , ...b ] = [ "FAIL", "PASS", 42 ];
+        var [ ...b ] = [ "PASS", 42 ];
         console.log.apply(console, b);
     }
     expect_stdout: "PASS 42"
@@ -270,7 +270,7 @@ retain_destructured_object_1: {
         "1 PASS",
         "2 42",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 retain_destructured_object_2: {
@@ -284,7 +284,7 @@ retain_destructured_object_2: {
             console.log(k, b[k]);
     }
     expect: {
-        var { foo: [], ...b } = { foo: [ "FAIL" ], bar: "PASS", baz: 42 };
+        var { foo: {}, ...b } = { foo: 0, bar: "PASS", baz: 42 };
         for (var k in b)
             console.log(k, b[k]);
     }
@@ -292,7 +292,7 @@ retain_destructured_object_2: {
         "bar PASS",
         "baz 42",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 retain_funarg_destructured_array_1: {
@@ -344,7 +344,7 @@ retain_funarg_destructured_object_1: {
         console.log((({ ...a }) => a)([ "PASS" ])[0]);
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 retain_funarg_destructured_object_2: {
@@ -362,7 +362,7 @@ retain_funarg_destructured_object_2: {
         }({ p: "FAIL" }).p || "PASS");
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 drop_unused_call_args_1: {
@@ -407,6 +407,24 @@ drop_unused_call_args_2: {
     node_version: ">=6"
 }
 
+maintain_position: {
+    options = {
+        unused: true,
+    }
+    input: {
+        A = "FAIL";
+        var [ , ...a ] = [ A, "PASS" ];
+        console.log(a[0]);
+    }
+    expect: {
+        A = "FAIL";
+        var [ , ...a ] = [ A, "PASS" ];
+        console.log(a[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 merge_funarg: {
     options = {
         merge_vars: true,
@@ -464,7 +482,7 @@ merge_funarg_destructured_object: {
         })([ "PASS" ]);
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_arguments: {
@@ -491,7 +509,7 @@ drop_rest_array: {
         rests: true,
     }
     input: {
-        var [ ...[ a ]] = [ "PASS" ];
+        var [ ...[ a ] ] = [ "PASS" ];
         console.log(a);
     }
     expect: {
@@ -542,6 +560,100 @@ drop_rest_lambda: {
     node_version: ">=6"
 }
 
+keep_rest_array: {
+    options = {
+        rests: true,
+    }
+    input: {
+        var [ ...[ ...a ] ] = "PASS";
+        console.log(a.join(""));
+    }
+    expect: {
+        var [ ...a ] = "PASS";
+        console.log(a.join(""));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_rest_arrow: {
+    options = {
+        arrows: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        rests: true,
+    }
+    input: {
+        console.log(((...[ ...a ]) => a.join(""))("PASS"));
+    }
+    expect: {
+        console.log(((...a) => a.join(""))("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_rest_lambda_1: {
+    options = {
+        keep_fargs: false,
+        reduce_vars: true,
+        rests: true,
+        toplevel: true,
+    }
+    input: {
+        function f(...[ ...a ]) {
+            return a.join("");
+        }
+        console.log(f("PASS"), f([ 42 ]));
+    }
+    expect: {
+        function f(...a) {
+            return a.join("");
+        }
+        console.log(f("PASS"), f([ 42 ]));
+    }
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+keep_rest_lambda_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        function f(...[ ...a ]) {
+            return a.join("");
+        }
+        console.log(f("PASS"), f([ 42 ]));
+    }
+    expect: {
+        function f(...[ ...a ]) {
+            return a.join("");
+        }
+        console.log(f("PASS"), f([ 42 ]));
+    }
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+drop_new_function: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        new function(...{
+            [console.log("PASS")]: a,
+        }) {}();
+    }
+    expect: {
+        void ([ ... {
+            [console.log("PASS")]: [].e,
+        }] = []);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 issue_4525_1: {
     options = {
         arguments: true,
@@ -647,6 +759,78 @@ issue_4544_2: {
     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"
+}
+
 issue_4562: {
     options = {
         evaluate: true,
@@ -667,7 +851,7 @@ issue_4562: {
 issue_4575: {
     options = {
         collapse_vars: true,
-        ie8: true,
+        ie: true,
         reduce_vars: true,
         rests: true,
         unused: true,
@@ -777,10 +961,247 @@ issue_4666: {
     expect: {
         var a = 0, b = 0;
         var o = (c => +a + c)([ b ]);
-        for(var k in o)
+        for (var k in o)
             b++;
         console.log(1, b);
     }
     expect_stdout: "1 2"
     node_version: ">=6"
 }
+
+issue_5089_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var {
+            p: [] = 42,
+            ...o
+        } = {
+            p: [],
+        };
+        console.log(o.p);
+    }
+    expect: {
+        var {
+            p: {},
+            ...o
+        } = {
+            p: 0,
+        };
+        console.log(o.p);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=8.3.0"
+}
+
+issue_5089_2: {
+    options = {
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        var {
+            p: {} = null,
+            ...o
+        } = {
+            p: {},
+        };
+        console.log(o.p);
+    }
+    expect: {
+        var {
+            p: {},
+            ...o
+        } = {
+            p: 0,
+        };
+        console.log(o.p);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=8.3.0"
+}
+
+issue_5100_1: {
+    options = {
+        passes: 2,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        [ {
+            p: {},
+            ...a
+        } ] = [ {
+            p: {
+                q: a,
+            } = 42,
+            r: "PASS",
+        } ];
+        console.log(a.r);
+    }
+    expect: {
+        var a;
+        ({
+            p: {},
+            ...a
+        } = [ {
+            p: [ a = 42["q"] ],
+            r: "PASS",
+        } ][0]);
+        console.log(a.r);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8.3.0"
+}
+
+issue_5100_2: {
+    options = {
+        passes: 2,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        [ {
+            p: {},
+            ...a
+        } ] = [ {
+            p: (console.log("PASS"), {
+                q: a,
+            } = 42),
+        } ];
+    }
+    expect: {
+        var a;
+        ({
+            p: {},
+            ...a
+        } = [ {
+            p: [ console.log("PASS"), a = 42["q"] ],
+        } ][0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=10.22.0"
+}
+
+issue_5108: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        rests: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        console.log(function([ ...[ a ] ]) {
+            return a;
+        }([ "PASS", "FAIL" ]));
+    }
+    expect: {
+        console.log(function([]) {
+            return "PASS";
+        }([ "PASS", "FAIL" ]));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5128_1: {
+    options = {
+        inline: true,
+    }
+    input: {
+        console.log(function() {
+            return function f(...[ a ]) {
+                return a;
+            }("PASS");
+        }());
+    }
+    expect: {
+        console.log(function f(...[ a ]) {
+            return a;
+        }("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5128_2: {
+    options = {
+        inline: true,
+        keep_fnames: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            return function f(...[ a ]) {
+                return a;
+            }("PASS");
+        }());
+    }
+    expect: {
+        console.log(function f(...[ a ]) {
+            return a;
+        }("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5165_1: {
+    options = {
+        conditionals: true,
+        dead_code: true,
+        evaluate: true,
+        reduce_vars: true,
+        rests: true,
+        side_effects: true,
+        switches: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(function([ ...a ]) {
+            switch (a) {
+              case a:
+                return "PASS";
+            }
+        }([]));
+    }
+    expect: {
+        console.log(function([ ...a ]) {
+            return "PASS";
+        }([]));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5165_2: {
+    options = {
+        conditionals: true,
+        dead_code: true,
+        evaluate: true,
+        reduce_vars: true,
+        rests: true,
+        side_effects: true,
+        switches: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(function(...a) {
+            switch (a) {
+              case a:
+                return "PASS";
+            }
+        }());
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/compress/sandbox.js

@@ -201,3 +201,20 @@ issue_4811_2: {
     expect_stdout: "PASS [object global] true"
     node_version: ">=8"
 }
+
+issue_5197: {
+    rename = true
+    input: {
+        function f(async) {
+            async(")=>{}");
+        }
+        console.log("" + this.__proto__);
+    }
+    expect: {
+        function f(a) {
+            a(")=>{}");
+        }
+        console.log("" + this.__proto__);
+    }
+    expect_stdout: "[object global]"
+}

test/compress/spreads.js

@@ -341,7 +341,7 @@ convert_setter: {
             console.log(k, o[k]);
     }
     expect_stdout: "PASS undefined"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_getter_1: {
@@ -370,7 +370,7 @@ keep_getter_1: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_getter_2: {
@@ -399,7 +399,7 @@ keep_getter_2: {
         "foo",
         "bar",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_getter_3: {
@@ -429,7 +429,7 @@ keep_getter_3: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_getter_4: {
@@ -460,7 +460,7 @@ keep_getter_4: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_accessor: {
@@ -508,7 +508,7 @@ keep_accessor: {
         "q undefined",
         "r null",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_key_order_1: {
@@ -538,7 +538,7 @@ object_key_order_1: {
         "a 3",
         "b 2",
     ]
-    node_version: ">=8 <=10"
+    node_version: ">=8.3.0 <=10"
 }
 
 object_key_order_2: {
@@ -568,7 +568,7 @@ object_key_order_2: {
         "a 3",
         "b 2",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_key_order_3: {
@@ -598,7 +598,7 @@ object_key_order_3: {
         "a 3",
         "b 2",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_key_order_4: {
@@ -628,7 +628,7 @@ object_key_order_4: {
         "a 3",
         "b 2",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_spread_array: {
@@ -654,7 +654,7 @@ object_spread_array: {
         "0 foo",
         "1 bar",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_spread_string: {
@@ -681,7 +681,7 @@ object_spread_string: {
         "1 o",
         "2 o",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 unused_var_side_effects: {
@@ -711,7 +711,7 @@ unused_var_side_effects: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 unsafe_join_1: {
@@ -793,7 +793,7 @@ issue_4329: {
         }[0]);
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4331: {
@@ -871,7 +871,7 @@ issue_4345: {
         }[42]);
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4361: {
@@ -901,7 +901,7 @@ issue_4361: {
         "foo",
         "undefined",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4363: {
@@ -922,7 +922,7 @@ issue_4363: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4556: {
@@ -945,78 +945,6 @@ issue_4556: {
     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"
-}
-
 issue_4614: {
     options = {
         pure_getters: "strict",
@@ -1066,7 +994,7 @@ issue_4849: {
         }()));
     }
     expect_stdout: "object"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4882_1: {
@@ -1098,7 +1026,7 @@ issue_4882_1: {
         "PASS",
         "undefined",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4882_2: {
@@ -1124,7 +1052,7 @@ issue_4882_2: {
         "42",
         "PASS",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4882_3: {
@@ -1154,5 +1082,25 @@ issue_4882_3: {
         "PASS",
         "42",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
+}
+
+issue_5006: {
+    options = {
+        arguments: true,
+    }
+    input: {
+        console.log(function(b, c) {
+            c = "FAIL 2";
+            return arguments[1];
+        }(...[], "FAIL 1") || "PASS");
+    }
+    expect: {
+        console.log(function(b, c) {
+            c = "FAIL 2";
+            return arguments[1];
+        }(...[], "FAIL 1") || "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
 }

test/compress/switches.js

@@ -113,7 +113,7 @@ constant_switch_5: {
         // the break inside the if ruins our job
         // we can still get rid of irrelevant cases.
         switch (1) {
-          case 1:
+          default:
             x();
             if (foo) break;
             y();
@@ -300,6 +300,37 @@ drop_default_2: {
     }
 }
 
+drop_default_3: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        switches: true,
+    }
+    input: {
+        function f() {
+            console.log("PASS");
+            return 42;
+        }
+        switch (42) {
+          case f():
+            break;
+          case void console.log("FAIL"):
+          default:
+        }
+    }
+    expect: {
+        function f() {
+            console.log("PASS");
+            return 42;
+        }
+        switch (42) {
+          case f():
+          case void console.log("FAIL"):
+        }
+    }
+    expect_stdout: "PASS"
+}
+
 keep_default: {
     options = {
         dead_code: true,
@@ -423,7 +454,6 @@ drop_case_3: {
         switch ({}.p) {
           default:
           case void 0:
-            break;
           case c = "FAIL":
         }
         console.log(c);
@@ -454,7 +484,168 @@ drop_case_4: {
     expect_stdout: "PASS"
 }
 
-keep_case: {
+drop_case_5: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        switches: true,
+    }
+    input: {
+        switch (42) {
+          case void console.log("PASS 1"):
+            console.log("FAIL 1");
+          case 42:
+          case console.log("FAIL 2"):
+            console.log("PASS 2");
+        }
+    }
+    expect: {
+        switch (42) {
+          default:
+            void console.log("PASS 1");
+            console.log("PASS 2");
+        }
+    }
+    expect_stdout: [
+        "PASS 1",
+        "PASS 2",
+    ]
+}
+
+drop_case_6: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        switches: true,
+    }
+    input: {
+        switch (console.log("PASS 1"), 2) {
+          case 0:
+            console.log("FAIL 1");
+          case (console.log("PASS 2"), 1):
+            console.log("FAIL 2");
+        }
+    }
+    expect: {
+        switch (console.log("PASS 1"), 2) {
+          case (console.log("PASS 2"), 1):
+        }
+    }
+    expect_stdout: [
+        "PASS 1",
+        "PASS 2",
+    ]
+}
+
+drop_case_7: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        switches: true,
+    }
+    input: {
+        switch (2) {
+          case 0:
+            console.log("FAIL 1");
+          case (console.log("PASS 1"), 1):
+            console.log("FAIL 2");
+          case 2:
+            console.log("PASS 2");
+        }
+    }
+    expect: {
+        switch (2) {
+          default:
+            console.log("PASS 1"), 1;
+            console.log("PASS 2");
+        }
+    }
+    expect_stdout: [
+        "PASS 1",
+        "PASS 2",
+    ]
+}
+
+drop_case_8: {
+    options = {
+        dead_code: true,
+        switches: true,
+    }
+    input: {
+        function log(msg) {
+            console.log(msg);
+            return msg;
+        }
+        switch (log("foo")) {
+          case "bar":
+            log("moo");
+            break;
+          case log("baz"):
+            log("moo");
+            break;
+          default:
+            log("moo");
+        }
+    }
+    expect: {
+        function log(msg) {
+            console.log(msg);
+            return msg;
+        }
+        switch (log("foo")) {
+          case "bar":
+          case log("baz"):
+          default:
+            log("moo");
+        }
+    }
+    expect_stdout: [
+        "foo",
+        "baz",
+        "moo",
+    ]
+}
+
+drop_case_9: {
+    options = {
+        dead_code: true,
+        switches: true,
+    }
+    input: {
+        function log(msg) {
+            console.log(msg);
+            return msg;
+        }
+        switch (log("foo")) {
+          case log("bar"):
+            log("moo");
+            break;
+          case "baz":
+            log("moo");
+            break;
+          default:
+            log("moo");
+        }
+    }
+    expect: {
+        function log(msg) {
+            console.log(msg);
+            return msg;
+        }
+        switch (log("foo")) {
+          default:
+            log("bar");
+            log("moo");
+        }
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+    ]
+}
+
+keep_case_1: {
     options = {
         dead_code: true,
         switches: true,
@@ -474,6 +665,76 @@ keep_case: {
     }
 }
 
+keep_case_2: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        switches: true,
+    }
+    input: {
+        switch ("foo") {
+          case console.log("bar"):
+          case console.log("baz"), "moo":
+        }
+    }
+    expect: {
+        switch ("foo") {
+          case console.log("bar"):
+          case console.log("baz"), "moo":
+        }
+    }
+    expect_stdout: [
+        "bar",
+        "baz",
+    ]
+}
+
+keep_case_3: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        switches: true,
+    }
+    input: {
+        var a;
+        switch (void console.log("PASS")) {
+          case a:
+          case console.log("FAIL"), 42:
+        }
+    }
+    expect: {
+        var a;
+        switch (void console.log("PASS")) {
+          case a:
+          case console.log("FAIL"), 42:
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+keep_case_4: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        switches: true,
+    }
+    input: {
+        var a;
+        switch (void console.log("PASS")) {
+          case a:
+          case void console.log("FAIL"):
+        }
+    }
+    expect: {
+        var a;
+        switch (void console.log("PASS")) {
+          case a:
+          case void console.log("FAIL"):
+        }
+    }
+    expect_stdout: "PASS"
+}
+
 issue_376: {
     options = {
         dead_code: true,
@@ -661,7 +922,7 @@ issue_1680_1: {
           case f(0):
           case f(1):
             f(2);
-          case 2:
+          default:
             f(5);
         }
     }
@@ -924,7 +1185,6 @@ issue_2535: {
     }
     expect: {
         w(), 42;
-        42;
         y();
         z();
     }
@@ -950,7 +1210,6 @@ issue_1750: {
     expect: {
         var a = 0, b = 1;
         true;
-        a, true;
         b = 2;
         console.log(a, b);
     }
@@ -1088,7 +1347,8 @@ drop_switch_6: {
         }
     }
     expect: {
-        A === B;
+        A;
+        B;
         x();
         C !== D;
         y();
@@ -1181,3 +1441,170 @@ issue_4059: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5008_1: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        reduce_vars: true,
+        switches: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(function f() {
+            switch (f) {
+              case f:
+                return "PASS";
+              default:
+                return "FAIL";
+            }
+        }());
+    }
+    expect: {
+        console.log(function f() {
+            switch (f) {
+              default:
+                return "PASS";
+            }
+        }());
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5008_2: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        reduce_vars: true,
+        switches: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(function(a) {
+            switch (a) {
+              case a:
+                return "PASS";
+              default:
+                return "FAIL";
+            }
+        }([]));
+    }
+    expect: {
+        console.log(function(a) {
+            switch (a) {
+              default:
+                return "PASS";
+            }
+        }([]));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5008_3: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        reduce_vars: true,
+        switches: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(function(a) {
+            switch (a) {
+              case a:
+                return "PASS";
+              default:
+                return "FAIL";
+            }
+        }({}));
+    }
+    expect: {
+        console.log(function(a) {
+            switch (a) {
+              default:
+                return "PASS";
+            }
+        }({}));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5008_4: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        reduce_vars: true,
+        switches: true,
+    }
+    input: {
+        console.log(function(a) {
+            switch (a) {
+              case a:
+                return "PASS";
+              default:
+                return "FAIL";
+            }
+        }(/foo/));
+    }
+    expect: {
+        console.log(function(a) {
+            switch (a) {
+              default:
+                return "PASS";
+            }
+        }(/foo/));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5010: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        switches: true,
+    }
+    input: {
+        var a;
+        switch (42) {
+          case console.log("PASS"):
+          case a:
+            console.log("FAIL");
+          case 42:
+        }
+    }
+    expect: {
+        var a;
+        switch (42) {
+          case console.log("PASS"):
+          case a:
+            console.log("FAIL");
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5012: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        switches: true,
+    }
+    input: {
+        switch (void 0) {
+          case console.log("PASS"):
+            break;
+          case void 0:
+          case 42:
+            console.log("FAIL");
+        }
+    }
+    expect: {
+        switch (void 0) {
+          case console.log("PASS"):
+            break;
+          default:
+            console.log("FAIL");
+        }
+    }
+    expect_stdout: "PASS"
+}

test/compress/templates.js

@@ -131,6 +131,105 @@ malformed_escape: {
     node_version: ">=4"
 }
 
+booleans: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        templates: true,
+    }
+    input: {
+        var a;
+        console.log(`$${a}${a}` ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a;
+        console.log("$" + a + a ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+escape_placeholder_1: {
+    options = {
+        templates: true,
+    }
+    input: {
+        console.log(`\${\n`);
+    }
+    expect: {
+        console.log(`\${
+`);
+    }
+    expect_stdout: [
+        "${",
+        "",
+    ]
+    node_version: ">=4"
+}
+
+escape_placeholder_2: {
+    options = {
+        evaluate: true,
+        templates: true,
+    }
+    input: {
+        console.log(`\n${"${"}\n`);
+    }
+    expect: {
+        console.log(`
+\${
+`);
+    }
+    expect_stdout: [
+        "",
+        "${",
+        "",
+    ]
+    node_version: ">=4"
+}
+
+escape_placeholder_3: {
+    options = {
+        evaluate: true,
+        templates: true,
+    }
+    input: {
+        console.log(`\n$${"{"}\n`);
+    }
+    expect: {
+        console.log(`
+\${
+`);
+    }
+    expect_stdout: [
+        "",
+        "${",
+        "",
+    ]
+    node_version: ">=4"
+}
+
+escape_placeholder_4: {
+    options = {
+        evaluate: true,
+        templates: true,
+    }
+    input: {
+        console.log(`\n${"$"}${"{"}\n`);
+    }
+    expect: {
+        console.log(`
+\${
+`);
+    }
+    expect_stdout: [
+        "",
+        "${",
+        "",
+    ]
+    node_version: ">=4"
+}
+
 evaluate: {
     options = {
         evaluate: true,
@@ -174,7 +273,7 @@ partial_evaluate: {
         console.log(`${6 * 7} foo ${console ? `PA` + "SS" : `FA` + `IL`}`);
     }
     expect: {
-        console.log(`42 foo ${console ? "PASS" : "FAIL"}`);
+        console.log("42 foo " + (console ? "PASS" : "FAIL"));
     }
     expect_stdout: "42 foo PASS"
     node_version: ">=4"
@@ -204,7 +303,7 @@ malformed_evaluate_2: {
         console.log(`\u0${0}b${5}`);
     }
     expect: {
-        console.log(`\u0${0}b5`);
+        console.log(`\u00b` + 5);
     }
     expect_stdout: true
     node_version: ">=4"
@@ -238,7 +337,7 @@ malformed_evaluate_4: {
         console.log("\\u00b5");
     }
     expect_stdout: "\\u00b5"
-    node_version: ">=8"
+    node_version: ">=8.10.0"
 }
 
 unsafe_evaluate: {
@@ -254,7 +353,7 @@ unsafe_evaluate: {
         console.log("\\uFo");
     }
     expect_stdout: "\\uFo"
-    node_version: ">=8"
+    node_version: ">=8.10.0"
 }
 
 side_effects_1: {
@@ -315,6 +414,21 @@ unsafe_side_effects: {
     node_version: ">=4"
 }
 
+pure_funcs: {
+    options = {
+        pure_funcs: "Math.random",
+        side_effects: true,
+    }
+    input: {
+        Math.random`${console.log("PASS")}`;
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 issue_4604: {
     options = {
         collapse_vars: true,
@@ -342,13 +456,14 @@ issue_4604: {
 issue_4606: {
     options = {
         evaluate: true,
+        strings: true,
         templates: true,
     }
     input: {
         console.log(`${typeof A} ${"\r"} ${"\\"} ${"`"}`);
     }
     expect: {
-        console.log(`${typeof A} \r \\ \``);
+        console.log(typeof A + " \r \\ `");
     }
     expect_stdout: "undefined \r \\ `"
     node_version: ">=4"
@@ -398,3 +513,259 @@ issue_4676: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4931: {
+    options = {
+        evaluate: true,
+        templates: true,
+        unsafe: true,
+    }
+    input: {
+        console.log(String.raw`${typeof A} ${"\r"}`);
+        console.log(String.raw`${"\\"} ${"`"}`);
+    }
+    expect: {
+        console.log(String.raw`${typeof A} ${"\r"}`);
+        console.log("\\ `");
+    }
+    expect_stdout: [
+        "undefined \r",
+        "\\ `",
+    ]
+    node_version: ">=4"
+}
+
+issue_5125_1: {
+    options = {
+        evaluate: true,
+        strings: true,
+        templates: true,
+    }
+    input: {
+        console.log(`PASS ${typeof A}`);
+    }
+    expect: {
+        console.log("PASS " + typeof A);
+    }
+    expect_stdout: "PASS undefined"
+    node_version: ">=4"
+}
+
+issue_5125_2: {
+    options = {
+        evaluate: true,
+        strings: true,
+        templates: true,
+    }
+    input: {
+        console.log(`PASS
+${typeof A}`);
+    }
+    expect: {
+        console.log(`PASS
+` + typeof A);
+    }
+    expect_stdout: [
+        "PASS",
+        "undefined",
+    ]
+    node_version: ">=4"
+}
+
+issue_5125_3: {
+    options = {
+        evaluate: true,
+        strings: true,
+        templates: true,
+    }
+    input: {
+        console.log(`PASS\n${typeof A}`);
+    }
+    expect: {
+        console.log(`PASS
+` + typeof A);
+    }
+    expect_stdout: [
+        "PASS",
+        "undefined",
+    ]
+    node_version: ">=4"
+}
+
+issue_5125_4: {
+    options = {
+        evaluate: true,
+        strings: true,
+        templates: true,
+    }
+    input: {
+        console.log(`PASS
+
+${typeof A}`);
+    }
+    expect: {
+        console.log(`PASS
+
+` + typeof A);
+    }
+    expect_stdout: [
+        "PASS",
+        "",
+        "undefined",
+    ]
+    node_version: ">=4"
+}
+
+issue_5125_5: {
+    options = {
+        evaluate: true,
+        strings: true,
+        templates: true,
+    }
+    input: {
+        console.log(`PASS\n\n${typeof A}`);
+    }
+    expect: {
+        console.log(`PASS
+
+` + typeof A);
+    }
+    expect_stdout: [
+        "PASS",
+        "",
+        "undefined",
+    ]
+    node_version: ">=4"
+}
+
+issue_5125_6: {
+    options = {
+        evaluate: true,
+        strings: true,
+        templates: true,
+    }
+    input: {
+        console.log(`${typeof A} ${typeof B} PASS`);
+    }
+    expect: {
+        console.log(typeof A + ` ${typeof B} PASS`);
+    }
+    expect_stdout: "undefined undefined PASS"
+    node_version: ">=4"
+}
+
+issue_5125_7: {
+    options = {
+        evaluate: true,
+        strings: true,
+        templates: true,
+    }
+    input: {
+        console.log(`${typeof A} ${typeof B} ${typeof C} PASS`);
+    }
+    expect: {
+        console.log(typeof A + ` ${typeof B} ${typeof C} PASS`);
+    }
+    expect_stdout: "undefined undefined undefined PASS"
+    node_version: ">=4"
+}
+
+issue_5125_8: {
+    options = {
+        evaluate: true,
+        strings: true,
+        templates: true,
+    }
+    input: {
+        console.log(`${typeof A}${typeof B}${typeof C} PASS`);
+    }
+    expect: {
+        console.log(typeof A + typeof B + typeof C + " PASS");
+    }
+    expect_stdout: "undefinedundefinedundefined PASS"
+    node_version: ">=4"
+}
+
+issue_5136: {
+    options = {
+        templates: true,
+    }
+    input: {
+        console.log(`${A = []}${A[0] = 42}`);
+    }
+    expect: {
+        console.log(`` + (A = []) + (A[0] = 42));
+    }
+    expect_stdout: "42"
+    node_version: ">=4"
+}
+
+issue_5145_1: {
+    options = {
+        strings: true,
+        templates: true,
+    }
+    input: {
+        var a = [];
+        console.log(`${a}${a[0] = 42}
+`);
+    }
+    expect: {
+        var a = [];
+        console.log(`${a}${a[0] = 42}
+`);
+    }
+    expect_stdout: [
+        "42",
+        "",
+    ]
+    node_version: ">=4"
+}
+
+issue_5145_2: {
+    options = {
+        strings: true,
+        templates: true,
+    }
+    input: {
+        var a = [];
+        console.log(`${a}${a}${a[0] = 42}
+`);
+    }
+    expect: {
+        var a = [];
+        console.log("" + a + a + (a[0] = 42) + `
+`);
+    }
+    expect_stdout: [
+        "42",
+        "",
+    ]
+    node_version: ">=4"
+}
+
+issue_5199: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function() {
+            console.log(typeof b);
+        }``;
+        {
+            const b = a;
+        }
+    }
+    expect: {
+        var a = function() {
+            console.log(typeof b);
+        }``;
+        {
+            const b = a;
+        }
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}

test/compress/transform.js

@@ -95,7 +95,7 @@ while_if_break: {
         }
     }
     expect: {
-        for(; a && (b && c && d, !e););
+        for (; a && (b && c && d, !e););
     }
 }
 

test/compress/unicode.js

@@ -67,7 +67,8 @@ unicode_escaped_identifier_2: {
     }
     expect_exact: 'var a="foo";var \u{10000}="bar";console.log(a,\u{10000});'
     expect_stdout: "foo bar"
-    node_version: ">=4"
+    // non-BMP support is platform-dependent on Node.js v4
+    node_version: ">=6"
 }
 
 unicode_identifier_ascii_only: {
@@ -200,7 +201,8 @@ surrogate_pair: {
     }
     expect_exact: 'var \ud87e\udc00={"\ud87e\udc01":"\udbc0\udc00"};\ud87e\udc00.\ud87e\udc02="\udbc0\udc01";console.log(typeof \ud87e\udc00,\ud87e\udc00.\ud87e\udc01,\ud87e\udc00["\ud87e\udc02"]);'
     expect_stdout: "object \udbc0\udc00 \udbc0\udc01"
-    node_version: ">=4"
+    // non-BMP support is platform-dependent on Node.js v4
+    node_version: ">=6"
 }
 
 surrogate_pair_ascii: {
@@ -216,5 +218,6 @@ surrogate_pair_ascii: {
     }
     expect_exact: 'var \\u{2f800}={"\\ud87e\\udc01":"\\udbc0\\udc00"};\\u{2f800}.\\u{2f802}="\\udbc0\\udc01";console.log(typeof \\u{2f800},\\u{2f800}.\\u{2f801},\\u{2f800}["\\ud87e\\udc02"]);'
     expect_stdout: "object \udbc0\udc00 \udbc0\udc01"
-    node_version: ">=4"
+    // non-BMP support is platform-dependent on Node.js v4
+    node_version: ">=6"
 }

test/compress/varify.js

@@ -111,7 +111,7 @@ hoist_props_const: {
         }
     }
     expect: {
-        var o_p = "PASS";
+        var o = 0, o_p = "PASS";
         console.log(o_p);
     }
     expect_stdout: "PASS"
@@ -136,7 +136,7 @@ hoist_props_let: {
     }
     expect: {
         "use strict";
-        var o_p = "PASS";
+        var o, o_p = "PASS";
         console.log(o_p);
     }
     expect_stdout: "PASS"
@@ -523,3 +523,93 @@ default_init: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4933_1: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        console.log(f());
+        function f() {
+            var a;
+            for (console in a = [ f ]) {
+                const b = a;
+            }
+        }
+    }
+    expect: {
+        console.log(function f() {
+            var a;
+            for (console in a = [ f ]) {
+                const b = a;
+            }
+        }());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4933_2: {
+    options = {
+        passes: 2,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        console.log(f());
+        function f() {
+            var a;
+            for (console in a = [ f ]) {
+                const b = a;
+            }
+        }
+    }
+    expect: {
+        console.log(function f() {
+            for (console in [ f ]);
+        }());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4954: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        "use strict";
+        (function() {
+            {
+                let a = console;
+                console.log(typeof a);
+            }
+            {
+                let a = function() {};
+                a && console.log(typeof a);
+            }
+        })();
+    }
+    expect: {
+        "use strict";
+        (function() {
+            var a = console;
+            console.log(typeof a);
+            {
+                let a = function() {};
+                a && console.log(typeof a);
+            }
+        })();
+    }
+    expect_stdout: [
+        "object",
+        "function",
+    ]
+    node_version: ">=4"
+}

test/compress/webkit.js

@@ -61,7 +61,7 @@ lambda_name_mangle: {
 
 lambda_name_mangle_ie8: {
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -95,7 +95,7 @@ function_name_mangle_ie8: {
         unused: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {

test/compress/yields.js

@@ -96,7 +96,7 @@ pause_resume: {
     node_version: ">=4"
 }
 
-arrow_yield: {
+arrow_yield_1: {
     input: {
         yield = "PASS";
         console.log(function*() {
@@ -108,6 +108,18 @@ arrow_yield: {
     node_version: ">=4"
 }
 
+arrow_yield_2: {
+    input: {
+        console.log(typeof function *() {
+            // Syntax error on Node.js v6+
+            return (yield) => {};
+        }().next().value);
+    }
+    expect_exact: "console.log(typeof function*(){return(yield)=>{}}().next().value);"
+    expect_stdout: "function"
+    node_version: "4"
+}
+
 for_of: {
     input: {
         function* f() {
@@ -958,7 +970,7 @@ issue_4639_1: {
         }().next().value());
     }
     expect_stdout: "PASS"
-    node_version: ">=4"
+    node_version: ">=4 <7 || >=8.7.0"
 }
 
 issue_4639_2: {
@@ -1083,3 +1095,217 @@ issue_4769_2: {
     expect_stdout: "PASS"
     node_version: ">=6"
 }
+
+issue_5019_1: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        (function(a) {
+            return a = function*() {
+                console.log(typeof a);
+            }();
+        })().next();
+    }
+    expect: {
+        (function(a) {
+            return a = function*() {
+                console.log(typeof a);
+            }();
+        })().next();
+    }
+    expect_stdout: "object"
+    node_version: ">=4"
+}
+
+issue_5019_2: {
+    options = {
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        var a = [];
+        for (var b in "foo")
+            a.push(function(c) {
+                return function*() {
+                    console.log(c);
+                }();
+            }(b));
+        a.map(function(d) {
+            return d.next();
+        });
+    }
+    expect: {
+        var a = [];
+        for (var b in "foo")
+            a.push(function(c) {
+                return function*() {
+                    console.log(c);
+                }();
+            }(b));
+        a.map(function(d) {
+            return d.next();
+        });
+    }
+    expect_stdout: [
+        "0",
+        "1",
+        "2",
+    ]
+    node_version: ">=4"
+}
+
+issue_5032_normal: {
+    options = {
+        merge_vars: true,
+        webkit: false,
+    }
+    input: {
+        function log(value) {
+            console.log(value);
+            return value;
+        }
+        function *f(a) {
+            var b = log(a), c = b;
+            log(b);
+            log(c);
+        }
+        f("PASS").next();
+    }
+    expect: {
+        function log(value) {
+            console.log(value);
+            return value;
+        }
+        function *f(c) {
+            var b = log(c), c = b;
+            log(b);
+            log(c);
+        }
+        f("PASS").next();
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+        "PASS",
+    ]
+    node_version: ">=4"
+}
+
+issue_5032_webkit: {
+    options = {
+        merge_vars: true,
+        webkit: true,
+    }
+    input: {
+        function log(value) {
+            console.log(value);
+            return value;
+        }
+        function *f(a) {
+            var b = log(a), c = b;
+            log(b);
+            log(c);
+        }
+        f("PASS").next();
+    }
+    expect: {
+        function log(value) {
+            console.log(value);
+            return value;
+        }
+        function *f(a) {
+            var b = log(a), c = b;
+            log(b);
+            log(c);
+        }
+        f("PASS").next();
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+        "PASS",
+    ]
+    node_version: ">=4"
+}
+
+issue_5034: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            var yield = function f() {
+                return function*() {
+                    return f;
+                };
+            };
+            return yield()().next().value === yield;
+        }() ? "PASS" : "FAIL");
+    }
+    expect: {
+        console.log(function() {
+            var yield = function f() {
+                return function*() {
+                    return f;
+                };
+            };
+            return yield()().next().value === yield;
+        }() ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5076: {
+    options = {
+        evaluate: true,
+        hoist_vars: true,
+        passes: 2,
+        pure_getters: "strict",
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+        yields: true,
+    }
+    input: {
+        var a;
+        console.log("PASS");
+        var b = function*({
+            p: {},
+        }) {}({
+            p: { a } = 42,
+        });
+    }
+    expect: {
+        var a;
+        console.log("PASS");
+        a = 42["a"];
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5177: {
+    options = {
+        properties: true,
+    }
+    input: {
+        console.log(typeof function*() {
+            return {
+                p(yield) {},
+            }.p;
+        }().next().value);
+    }
+    expect: {
+        console.log(typeof function*() {
+            return {
+                p(yield) {},
+            }.p;
+        }().next().value);
+    }
+    expect_stdout: "function"
+    node_version: ">=4"
+}

test/input/invalid/optional-template.js

@@ -0,0 +1 @@
+console?.log``;

test/input/reduce/diff_error.reduced.js

@@ -1,7 +1,5 @@
 // (beautified)
-console.log(function() {
+console.log(1 + .1 + .1);
-    return 1 + .1 + .1;
-}());
 // output: 1.2000000000000002
 // 
 // minify: 1.2

test/jetstream.js

@@ -58,22 +58,31 @@ if (typeof phantom == "undefined") {
     }).listen();
     server.on("listening", function() {
         var port = server.address().port;
-        if (debug) {
+        if (debug) return console.log("http://localhost:" + port + "/");
-            console.log("http://localhost:" + port + "/");
+        var cmd = process.platform == "win32" ? "npm.cmd" : "npm";
-        } else (function install() {
+
-            child_process.spawn(process.platform == "win32" ? "npm.cmd" : "npm", [
+        function npm(args, done) {
+            child_process.spawn(cmd, args, { stdio: [ "ignore", 1, 2 ] }).on("exit", done);
+        }
+
+        (function install() {
+            npm([
                 "install",
+                "graceful-fs@4.2.6",
+                "is-my-json-valid@2.20.5",
                 "phantomjs-prebuilt@2.1.14",
                 "--no-audit",
                 "--no-optional",
                 "--no-save",
                 "--no-update-notifier",
-            ], {
+            ], function(code) {
-                stdio: [ "ignore", 1, 2 ]
-            }).on("exit", function(code) {
                 if (code) {
                     console.log("npm install failed with code", code);
-                    return install();
+                    return npm([
+                        "cache",
+                        "clean",
+                        "--force",
+                    ], install);
                 }
                 var program = require("phantomjs-prebuilt").exec(process.argv[1], port);
                 program.stdout.pipe(process.stdout);

test/mocha/cli.js

@@ -721,6 +721,20 @@ describe("bin/uglifyjs", function() {
             done();
         });
     });
+    it("Should throw syntax error (console?.log``)", function(done) {
+        var command = uglifyjscmd + " test/input/invalid/optional-template.js";
+        exec(command, function(err, stdout, stderr) {
+            assert.ok(err);
+            assert.strictEqual(stdout, "");
+            assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+                "Parse error at test/input/invalid/optional-template.js:1,12",
+                "console?.log``;",
+                "            ^",
+                "ERROR: Invalid template on optional chain",
+            ].join("\n"));
+            done();
+        });
+    });
     it("Should handle literal string as source map input", function(done) {
         var command = [
             uglifyjscmd,

test/mocha/comments.js

@@ -191,7 +191,7 @@ describe("comments", function() {
     });
 
     it("Should correctly preserve new lines around comments", function() {
-        var tests = [
+        [
             [
                 "// foo",
                 "// bar",

test/mocha/glob.js

@@ -1,7 +1,6 @@
 var assert = require("assert");
 var exec = require("child_process").exec;
 var path = require("path");
-var readFileSync = require("fs").readFileSync;
 
 describe("bin/uglifyjs with input file globs", function() {
     var uglifyjscmd = '"' + process.argv[0] + '" bin/uglifyjs';

test/mocha/ie8.js

@@ -1,21 +0,0 @@
-var assert = require("assert");
-var UglifyJS = require("../..");
-
-describe("ie8", function() {
-    it("Should be able to minify() with undefined as catch parameter in a try...catch statement", function() {
-        assert.strictEqual(
-            UglifyJS.minify([
-                "function a(b){",
-                "    try {",
-                "        throw 'Stuff';",
-                "    } catch (undefined) {",
-                "        console.log('caught: ' + undefined);",
-                "    }",
-                "    console.log('undefined is ' + undefined);",
-                "    return b === undefined;",
-                "};",
-            ].join("\n")).code,
-            'function a(o){try{throw"Stuff"}catch(o){console.log("caught: "+o)}return console.log("undefined is "+void 0),void 0===o}'
-        );
-    });
-});

test/mocha/let.js

@@ -1,5 +1,5 @@
 var assert = require("assert");
-var UglifyJS = require("../..");
+var UglifyJS = require("../node");
 
 describe("let", function() {
     this.timeout(30000);
@@ -7,11 +7,11 @@ describe("let", function() {
         // Produce a lot of variables in a function and run it through mangle.
         var s = '"dddddeeeeelllllooooottttt"; function foo() {';
         for (var i = 0; i < 18000; i++) {
-            s += "var v" + i + "=0;";
+            s += "var v" + i + "=[];";
         }
         s += '}';
         var result = UglifyJS.minify(s, {
-            compress: false
+            compress: false,
         }).code;
 
         // Verify that select keywords and reserved keywords not produced
@@ -41,7 +41,7 @@ describe("let", function() {
         }
         var result = UglifyJS.minify(s, {
             compress: false,
-            ie8: true,
+            ie: true,
             mangle: {
                 properties: true,
             }
@@ -54,4 +54,43 @@ describe("let", function() {
             assert.notStrictEqual(result.indexOf('v["' + name + '"]'), -1);
         });
     });
+    it("Should parse `let` as name correctly", function() {
+        [
+            "for(var let;let;let)let;",
+            "function let(let){let}",
+        ].forEach(function(code) {
+            var ast = UglifyJS.parse(code);
+            assert.strictEqual(ast.print_to_string(), code);
+            assert.throws(function() {
+                UglifyJS.parse('"use strict";' + code);
+            }, function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error && e.message == "Unexpected let in strict mode";
+            }, code);
+        });
+    });
+    it("Should throw on ambiguous use of `let`", function() {
+        [
+            "export let",
+            [
+                "let",
+                "console.log(42)",
+            ].join("\n"),
+            [
+                "let",
+                "[ console.log(42) ]",
+            ].join("\n"),
+            [
+                "let",
+                "{",
+                "    console.log(42)",
+                "}",
+            ].join("\n"),
+        ].forEach(function(code) {
+            assert.throws(function() {
+                UglifyJS.parse(code);
+            }, function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error;
+            }, code);
+        });
+    });
 });

test/mocha/minify.js

@@ -25,7 +25,7 @@ describe("minify", function() {
         if (result.error) throw result.error;
         assert.strictEqual(result.code, "print(42);");
         assert.strictEqual(JSON.stringify(options), value);
-    })
+    });
     it("Should skip inherited keys from `files`", function() {
         var files = Object.create({ skip: this });
         files[0] = "alert(1 + 1)";

test/mocha/reduce.js

@@ -1,5 +1,4 @@
 var assert = require("assert");
-var exec = require("child_process").exec;
 var fs = require("fs");
 var reduce_test = require("../reduce");
 var semver = require("semver");
@@ -282,35 +281,40 @@ describe("test/reduce.js", function() {
         });
         if (result.error) throw result.error;
         assert.deepEqual(result.warnings, []);
-        assert.strictEqual(result.code.replace(/function \(/g, "function("), (semver.satisfies(process.version, "<=0.10") ? [
+        if (semver.satisfies(process.version, "<=0.10")) {
-            "// Can't reproduce test failure",
+            assert.strictEqual(result.code, [
-            "// minify options: {",
+                "// Can't reproduce test failure",
-            '//   "compress": false,',
+                "// minify options: {",
-            '//   "mangle": false,',
+                '//   "compress": false,',
-            '//   "output": {',
+                '//   "mangle": false,',
-            '//     "beautify": true',
+                '//   "output": {',
-            "//   }",
+                '//     "beautify": true',
-            "// }",
+                "//   }",
-        ] : [
+                "// }",
-            [
+            ].join("\n"));
-                "try{",
+        } else {
-                "null[function(){}]",
+            var message = result.code.split(/\n/, 3)[1].slice("// output: ".length);
-                "}catch(e){",
+            assert.strictEqual(result.code, [
-                "console.log(e)",
+                [
-                "}",
+                    "try{",
-            ].join(""),
+                    "null[function(){}]",
-            "// output: TypeError: Cannot read property 'function(){}' of null",
+                    "}catch(e){",
-            "// ",
+                    "console.log(e)",
-            "// minify: TypeError: Cannot read property 'function() {}' of null",
+                    "}",
-            "// ",
+                ].join(""),
-            "// options: {",
+                "// output: " + message,
-            '//   "compress": false,',
+                "// ",
-            '//   "mangle": false,',
+                "// minify: " + message.replace("(){}", "() {}"),
-            '//   "output": {',
+                "// ",
-            '//     "beautify": true',
+                "// options: {",
-            "//   }",
+                '//   "compress": false,',
-            "// }",
+                '//   "mangle": false,',
-        ]).join("\n"));
+                '//   "output": {',
+                '//     "beautify": true',
+                "//   }",
+                "// }",
+            ].join("\n"));
+        }
     });
     it("Should maintain block-scope for const/let", function() {
         if (semver.satisfies(process.version, "<4")) return;

test/mocha/sourcemaps.js

@@ -101,6 +101,19 @@ describe("sourcemaps", function() {
         var map = JSON.parse(result.map);
         assert.deepEqual(map.names, []);
     });
+    it("Should mark class properties", function() {
+        var result = UglifyJS.minify([
+            "class A {",
+            "    static P = 42",
+            "    set #q(v) {}",
+            "}",
+        ].join("\n"), {
+            sourceMap: true,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, "class A{static P=42;set#q(s){}}");
+        assert.strictEqual(result.map, '{"version":3,"sources":["0"],"names":["A","P","#q","v"],"mappings":"MAAMA,EACFC,SAAW,GACXC,MAAOC"}');
+    });
     it("Should mark array/object literals", function() {
         var result = UglifyJS.minify([
             "var obj = {};",
@@ -349,7 +362,7 @@ describe("sourcemaps", function() {
         it("Should not modify input source map", function() {
             var orig = get_map();
             var original = JSON.stringify(orig);
-            var map = prepare_map(orig);
+            prepare_map(orig);
             assert.strictEqual(JSON.stringify(orig), original);
         });
         it("Should copy over original sourcesContent", function() {

test/mocha/spidermonkey.js

@@ -4,34 +4,27 @@ var UglifyJS = require("../..");
 
 describe("spidermonkey export/import sanity test", function() {
     it("Should produce a functional build when using --self with spidermonkey", function(done) {
-        this.timeout(60000);
+        this.timeout(120000);
-
         var uglifyjs = '"' + process.argv[0] + '" bin/uglifyjs';
-        var command = uglifyjs + " --self -cm --wrap SpiderUglify -o spidermonkey | " +
+        var command = [
-            uglifyjs + " -p spidermonkey -cm";
+            uglifyjs + " --self -cm --wrap SpiderUglify -o spidermonkey",
-
+            uglifyjs + " -p spidermonkey -cm",
-        exec(command, {
+        ].join(" | ");
-            maxBuffer: 1048576
+        exec(command, { maxBuffer: 1048576 }, function(err, stdout) {
-        }, function(err, stdout) {
             if (err) throw err;
-
             eval(stdout);
             assert.strictEqual(typeof SpiderUglify, "object");
             var result = SpiderUglify.minify("foo([true,,2+3]);");
             assert.strictEqual(result.error, undefined);
             assert.strictEqual(result.code, "foo([!0,,5]);");
-
             done();
         });
     });
 
-    it("Should not add unnecessary escape slashes to regexps", function() {
+    it("Should not add unnecessary escape slashes to RegExp", function() {
         var input = "/[\\\\/]/;";
         var ast = UglifyJS.parse(input).to_mozilla_ast();
-        assert.equal(
+        assert.strictEqual(UglifyJS.AST_Node.from_mozilla_ast(ast).print_to_string(), input);
-            UglifyJS.AST_Node.from_mozilla_ast(ast).print_to_string(),
-            input
-        );
     });
 
     it("Should judge between directives and strings correctly on import", function() {

test/mocha/string-literal.js

@@ -12,7 +12,7 @@ describe("String literals", function() {
             '"\u2029"',
         ].forEach(function(input) {
             assert.throws(function() {
-                var ast = UglifyJS.parse(input);
+                UglifyJS.parse(input);
             }, function(e) {
                 return e instanceof UglifyJS.JS_Parse_Error
                     && e.message === "Unterminated string constant";
@@ -44,7 +44,7 @@ describe("String literals", function() {
             '"use strict";\n"\\011"',
         ].forEach(function(input) {
             assert.throws(function() {
-                var output = UglifyJS.parse(input);
+                UglifyJS.parse(input);
             }, function(e) {
                 return e instanceof UglifyJS.JS_Parse_Error
                     && e.message === "Legacy octal escape sequences are not allowed in strict mode";

test/mocha/templates.js

@@ -34,20 +34,20 @@ describe("Template literals", function() {
         [
             // native line breaks
             [ "`foo\nbar`", "`foo\nbar`" ],
-            [ "`foo\rbar`", "`foo\rbar`" ],
+            [ "`foo\rbar`", "`foo\nbar`" ],
             [ "`foo\r\nbar`", "`foo\nbar`" ],
-            [ "`foo\r\n\rbar`", "`foo\n\rbar`" ],
+            [ "`foo\r\n\rbar`", "`foo\n\nbar`" ],
             // escaped line breaks
             [ "`foo\\nbar`", "`foo\\nbar`" ],
             [ "`foo\\rbar`", "`foo\\rbar`" ],
-            [ "`foo\r\\nbar`", "`foo\r\\nbar`" ],
+            [ "`foo\r\\nbar`", "`foo\n\\nbar`" ],
             [ "`foo\\r\nbar`", "`foo\\r\nbar`" ],
             [ "`foo\\r\\nbar`", "`foo\\r\\nbar`" ],
             // continuation
             [ "`foo\\\nbar`", "`foo\\\nbar`" ],
-            [ "`foo\\\rbar`", "`foo\\\rbar`" ],
+            [ "`foo\\\rbar`", "`foo\\\nbar`" ],
             [ "`foo\\\r\nbar`", "`foo\\\nbar`" ],
-            [ "`foo\\\r\n\rbar`", "`foo\\\n\rbar`" ],
+            [ "`foo\\\r\n\rbar`", "`foo\\\n\nbar`" ],
             [ "`foo\\\\nbar`", "`foo\\\\nbar`" ],
             [ "`foo\\\\rbar`", "`foo\\\\rbar`" ],
             [ "`foo\\\\r\nbar`", "`foo\\\\r\nbar`" ],

test/reduce.js

@@ -22,7 +22,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
     reduce_options = reduce_options || {};
     var print_options = {};
     [
-        "ie8",
+        "ie",
         "v8",
         "webkit",
     ].forEach(function(name) {
@@ -46,7 +46,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
     if (verbose) {
         log("// Node.js " + process.version + " on " + os.platform() + " " + os.arch());
     }
-    if (differs.error && [ "DefaultsError", "SyntaxError" ].indexOf(differs.error.name) < 0) {
+    if (differs && differs.error && [ "DefaultsError", "SyntaxError" ].indexOf(differs.error.name) < 0) {
         test_for_diff = test_minify;
         differs = test_for_diff(testcase, minify_options, result_cache, max_timeout);
     }
@@ -132,6 +132,8 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 return;
             }
             if (parent instanceof U.AST_VarDef && parent.name === node) return;
+            // preserve class methods
+            if (parent instanceof U.AST_ClassMethod && parent.value === node) return;
             // preserve exports
             if (parent instanceof U.AST_ExportDeclaration) return;
             if (parent instanceof U.AST_ExportDefault) return;
@@ -147,6 +149,9 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
             if (parent instanceof U.AST_For && parent.init === node && node instanceof U.AST_Definitions) return node;
             // preserve for (xxx in/of ...)
             if (parent instanceof U.AST_ForEnumeration && parent.init === node) return node;
+            // preserve super(...)
+            if (node.TYPE == "Call" && node.expression instanceof U.AST_Super) return;
+            if (node instanceof U.AST_Super && parent.TYPE == "Call" && parent.expression === node) return node;
 
             // node specific permutations with no parent logic
 
@@ -210,9 +215,9 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     // hoist and return expressions from the IIFE function expression
                     var seq = [];
                     node.expression.body.forEach(function(node) {
-                        var expr = expr instanceof U.AST_Exit ? node.value : node.body;
+                        var expr = node instanceof U.AST_Exit ? node.value : node.body;
                         if (expr instanceof U.AST_Node && !U.is_statement(expr) && can_hoist(expr)) {
-                            // collect expressions from each statements' body
+                            // collect expressions from each statement's body
                             seq.push(expr);
                         }
                     });
@@ -390,7 +395,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 var expr = [
                     node.expression,                         // switch expression
                     node.body[0] && node.body[0].expression, // first case expression or undefined
-                    node.body[0] && node.body[0],            // first case body or undefined
+                    node.body[0],                            // first case body or undefined
                 ][ (node.start._permute * steps | 0) % 4 ];
                 node.start._permute += step;
                 if (expr && (!(expr instanceof U.AST_Statement) || !has_loopcontrol(expr, node, parent))) {
@@ -721,7 +726,7 @@ function to_statement_init(node) {
     return node instanceof U.AST_Const || node instanceof U.AST_Let ? new U.AST_BlockStatement({
         body: [ node ],
         start: {},
-    }) : to_statement(node);;
+    }) : to_statement(node);
 }
 
 function wrap_with_console_log(node) {

test/release/acorn.sh

@@ -14,6 +14,13 @@ minify_in_situ() {
     uglify-js $ARGS
 }
 
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
 rm -rf tmp/acorn \
 && git clone https://github.com/acornjs/acorn.git tmp/acorn \
 && cd tmp/acorn \
@@ -89,7 +96,7 @@ minify_in_situ "acorn/src" \
 && minify_in_situ "acorn-loose/src" \
 && minify_in_situ "acorn-walk/src" \
 && rm -rf node_modules \
-&& npm install \
+&& npm_install \
 && rm -rf acorn/dist acorn-loose/dist acorn-walk/dist \
 && npm run build \
 && minify_in_situ "acorn/dist" \

test/release/bootstrap.sh

@@ -14,6 +14,13 @@ minify_in_situ() {
     uglify-js $ARGS
 }
 
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
 rm -rf tmp/bootstrap \
 && git clone --depth 1 --branch v5.0.0-beta2 https://github.com/twbs/bootstrap.git tmp/bootstrap \
 && cd tmp/bootstrap \
@@ -171,7 +178,7 @@ rm -rf tmp/bootstrap \
 EOF
 ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
 rm -rf node_modules \
-&& npm ci \
+&& npm_install \
 && minify_in_situ "node_modules/@popperjs/core" \
 && rm -rf dist/js/* \
 && minify_in_situ "build" \

test/release/buble.sh

@@ -14,6 +14,13 @@ minify_in_situ() {
     uglify-js $ARGS
 }
 
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
 rm -rf tmp/buble \
 && git clone https://github.com/bublejs/buble.git tmp/buble \
 && cd tmp/buble \
@@ -38,7 +45,7 @@ EOF
 ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
 minify_in_situ "src" \
 && rm -rf node_modules \
-&& npm ci \
+&& npm_install \
 && rm -rf dist \
 && npm run build \
 && minify_in_situ "dist" \

test/release/butternut.sh

@@ -14,6 +14,13 @@ minify_in_situ() {
     uglify-js $ARGS
 }
 
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
 rm -rf tmp/butternut \
 && git clone https://github.com/Rich-Harris/butternut.git tmp/butternut \
 && cd tmp/butternut \
@@ -38,7 +45,7 @@ EOF
 ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
 minify_in_situ "src" \
 && rm -rf node_modules \
-&& npm install \
+&& npm_install \
 && rm -rf dist \
 && npm run build \
 && minify_in_situ "dist" \

test/release/install.sh

@@ -36,7 +36,9 @@ EOF
 }
 if [ $NATIVE ]; then unset -f timeout; fi
 
-git clone --branch v1.6.0 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs
+while !(git clone --branch v1.6.0 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs); do
+    rm -rf ~/.nvs
+done
 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
@@ -51,4 +53,6 @@ npm config set save false
 npm config set strict-ssl false
 npm config set update-notifier false
 npm --version
-while !(npm install); do echo "'npm install' failed - retrying..."; done
+while !(npm install); do
+    while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+done

test/release/mathjs.sh

@@ -18,6 +18,13 @@ minify_in_situ() {
     uglify-js $ARGS
 }
 
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
 rm -rf tmp/mathjs \
 && git clone --depth 1 --branch v9.2.0 https://github.com/josdejong/mathjs.git tmp/mathjs \
 && cd tmp/mathjs \
@@ -191,7 +198,7 @@ minify_in_situ "bin" \
 && minify_in_situ "test" \
 && minify_in_situ "tools" \
 && rm -rf node_modules \
-&& npm ci \
+&& npm_install \
 && rm -rf lib \
 && npm run build \
 && minify_in_situ "lib" \

test/release/rollup-es.sh

@@ -14,6 +14,13 @@ minify_in_situ() {
     uglify-js $ARGS
 }
 
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
 rm -rf tmp/rollup \
 && git clone https://github.com/rollup/rollup.git tmp/rollup \
 && cd tmp/rollup \
@@ -77,7 +84,7 @@ minify_in_situ "bin" \
 && minify_in_situ "browser" \
 && minify_in_situ "src" \
 && rm -rf node_modules \
-&& npm ci \
+&& npm_install \
 && rm -rf dist \
 && npm run build \
 && minify_in_situ "dist" \

test/release/rollup-ts.sh

@@ -24,6 +24,13 @@ EOF
     uglify-js $ARGS
 }
 
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
 rm -rf tmp/rollup \
 && git clone --depth 1 --branch v2.39.1 https://github.com/rollup/rollup.git tmp/rollup \
 && cd tmp/rollup \
@@ -36,6 +43,9 @@ rm -rf tmp/rollup \
 -    "postpublish": "pinst --enable",
 -    "prepare": "npm run build",
 -    "prepublishOnly": "pinst --disable && npm ci && npm run lint:nofix && npm run security && npm run build:bootstrap && npm run test:all",
+@@ -93 +89 @@
+-    "is-reference": "lukastaegert/is-reference#update-class-features",
++    "is-reference": "3.0.0",
 --- a/test/cli/index.js
 +++ b/test/cli/index.js
 @@ -13,0 +14,3 @@ sander.rimrafSync(__dirname, 'node_modules');
@@ -44,11 +54,11 @@ rm -rf tmp/rollup \
 +sander.rimrafSync(__dirname, 'samples', 'watch', 'watch-config-initial-error');
 EOF
 ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
-npm install esbuild-wasm@0.8.56 \
+npm_install esbuild-wasm@0.8.56 \
 && minify_in_situ "cli" \
 && minify_in_situ "src" \
 && rm -rf node_modules \
-&& npm ci \
+&& npm_install \
 && rm -rf dist \
 && npm run build \
 && minify_in_situ "dist" \

test/release/sucrase.sh

@@ -28,6 +28,13 @@ EOF
     uglify-js $ARGS
 }
 
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
 rm -rf tmp/sucrase \
 && git clone https://github.com/alangpierce/sucrase.git tmp/sucrase \
 && cd tmp/sucrase \
@@ -83,10 +90,10 @@ rm -rf tmp/sucrase \
 +export { getJSXPragmaInfo as HACK };
 EOF
 ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
-npm install esbuild-wasm@0.8.56 \
+npm_install esbuild-wasm@0.8.56 \
 && minify_in_situ "src" \
 && rm -rf node_modules \
-&& npm install \
+&& npm_install \
 && npm run clean \
 && npm run build \
 && minify_in_situ "dist" \

test/release/web-tooling-benchmark.sh

@@ -14,6 +14,13 @@ minify_in_situ() {
     uglify-js $ARGS
 }
 
+npm_install() {
+    PKG="$1"
+    while !(npm install $PKG); do
+        while !(npm cache clean --force); do echo "'npm cache clean' failed - retrying..."; done
+    done
+}
+
 rm -rf tmp/web-tooling-benchmark \
 && git clone --depth 1 --branch v0.5.3 https://github.com/v8/web-tooling-benchmark.git tmp/web-tooling-benchmark \
 && cd tmp/web-tooling-benchmark \
@@ -47,7 +54,7 @@ ERR=$?; if [ "$ERR" != "0" ]; then echo "Error: $ERR"; exit $ERR; fi
 minify_in_situ "src" \
 && minify_in_situ "third_party" \
 && rm -rf node_modules \
-&& npm ci \
+&& npm_install \
 && rm -rf build/* \
 && npm run build:terser-bundled \
 && npm run build:uglify-js-bundled \

test/sandbox.js

@@ -27,8 +27,8 @@ exports.run_code = semver.satisfies(process.version, "0.8") ? function(code, top
 } : semver.satisfies(process.version, "<0.12") ? run_code_vm : function(code, toplevel, timeout) {
     if ([
         /\basync[ \t]*\([\s\S]*?\)[ \t]*=>/,
-        /\b(async[ \t]+function|setImmediate|setInterval|setTimeout)\b/,
+        /\b(async[ \t]+function|Promise|setImmediate|setInterval|setTimeout)\b/,
-        /\basync([ \t]+|[ \t]*\*[ \t]*)[^\s()[\]{},.&|!~=*%/+-]+(\s*\(|[ \t]*=>)/,
+        /\basync([ \t]+|[ \t]*#|[ \t]*\*[ \t]*)[^\s()[\]{}#:;,.&|!~=*%/+-]+(\s*\(|[ \t]*=>)/,
     ].some(function(pattern) {
         return pattern.test(code);
     })) {
@@ -51,13 +51,13 @@ exports.same_stdout = semver.satisfies(process.version, "0.12") ? function(expec
 };
 exports.patch_module_statements = function(code) {
     var count = 0, imports = [];
-    code = code.replace(/\bexport(?:\s*\{[^}]*}\s*?(?:$|\n|;)|\s+default\b(?:\s*(\(|\{|class\s*\{|class\s+(?=extends\b)|(?:async\s+)?function\s*(?:\*\s*)?\())?|\b)/g, function(match, header) {
+    code = code.replace(/\bexport(?:\s*\{[^{}]*}\s*?(?:$|\n|;)|\s+default\b(?:\s*(\(|\{|class\s*\{|class\s+(?=extends\b)|(?:async\s+)?function\s*(?:\*\s*)?\())?|\b)/g, function(match, header) {
         if (!header) return "";
         if (header.length == 1) return "0, " + header;
         return header.slice(0, -1) + " _" + ++count + header.slice(-1);
     }).replace(/\bimport\.meta\b/g, function() {
         return '({ url: "https://example.com/path/index.html" })';
-    }).replace(/\bimport\b(?:\s*([^('"]+)\bfrom\b)?\s*(['"]).*?\2(?:$|\n|;)/g, function(match, symbols) {
+    }).replace(/\bimport\b(?:\s*([^\s('"][^('"]*)\bfrom\b)?\s*(['"]).*?\2(?:$|\n|;)/g, function(match, symbols) {
         if (symbols) {
             if (!/^[{*]/.test(symbols)) symbols = "default:" + symbols;
             symbols = symbols.replace(/[{}]/g, "").trim().replace(/\s*,\s*/g, ",");
@@ -202,13 +202,11 @@ function setup(global, builtins, setup_log, setup_tty) {
     });
     Object.defineProperties(global, props);
     // for Node.js v8+
-    if (global.toString !== Object.prototype.toString) {
+    global.__proto__ = Object.defineProperty(Object.create(global.__proto__), "toString", {
-        global.__proto__ = Object.defineProperty(Object.create(global.__proto__), "toString", {
+        value: function() {
-            value: function() {
+            return "[object global]";
-                return "[object global]";
+        },
-            },
+    });
-        });
-    }
 
     function self() {
         return this;
@@ -254,8 +252,11 @@ function run_code_vm(code, toplevel, timeout) {
         var ctx = vm.createContext({ console: console });
         // for Node.js v6
         vm.runInContext(setup_code, ctx);
-        vm.runInContext(toplevel ? "(function(){" + code + "})();" : code, ctx, { timeout: timeout });
+        vm.runInContext(toplevel ? "(function(){\n" + code + "\n})();" : code, ctx, { timeout: timeout });
-        return strip_color_codes(stdout);
+        // for Node.js v4
+        return strip_color_codes(stdout.replace(/\b(Array \[|Object {)/g, function(match) {
+            return match.slice(-1);
+        }));
     } catch (ex) {
         return ex;
     } finally {
@@ -265,7 +266,7 @@ function run_code_vm(code, toplevel, timeout) {
 
 function run_code_exec(code, toplevel, timeout) {
     if (toplevel) {
-        code = setup_code + "(function(){" + code + "})();";
+        code = setup_code + "(function(){\n" + code + "\n})();";
     } else {
         code = code.replace(/^((["'])[^"']*\2(;|$))?/, function(directive) {
             return directive + setup_code;
@@ -278,11 +279,11 @@ function run_code_exec(code, toplevel, timeout) {
         timeout: timeout || 5000,
     });
     if (result.status === 0) return result.stdout;
+    var msg = ("" + result.stderr).replace(/\r\n/g, "\n");
     if (result.error && result.error.code == "ETIMEDOUT" || /FATAL ERROR:/.test(msg)) {
         return new Error("Script execution timed out.");
     }
     if (result.error) return result.error;
-    var msg = result.stderr.replace(/\r\n/g, "\n");
     var end = msg.indexOf("\n\n-----===== UNCAUGHT EXCEPTION =====-----\n\n");
     var details;
     if (end >= 0) {
@@ -294,7 +295,7 @@ function run_code_exec(code, toplevel, timeout) {
         } catch (e) {}
     }
     var match = /\n([^:\s]*Error)(?:: ([\s\S]+?))?\n(    at [\s\S]+)\n$/.exec(msg);
-    if (!match) return details;
+    if (!match) return details || new Error("Script execution aborted.");
     var ex = new global[match[1]](match[2]);
     ex.stack = ex.stack.slice(0, ex.stack.indexOf("    at ")) + match[3];
     if (typeof details == "object") {

test/ufuzz/actions.js

@@ -1,7 +1,7 @@
 var get = require("https").get;
 var parse = require("url").parse;
 
-var base, token, run_number, eldest = true;
+var base, token, run_number;
 exports.init = function(url, auth, num) {
     base = url;
     token = auth;
@@ -19,14 +19,14 @@ exports.should_stop = function(callback) {
             do {
                 workflow = runs.pop();
                 if (!workflow) return;
-                if (workflow.event == "schedule" && workflow.run_number == run_number) found = true;
+                if (is_cron(workflow) && workflow.run_number == run_number) found = true;
             } while (!found && workflow.status == "completed");
             read(workflow.jobs_url, function(reply) {
                 if (!reply || !Array.isArray(reply.jobs)) return;
                 if (!reply.jobs.every(function(job) {
                     if (job.status == "completed") return true;
                     remaining--;
-                    return found || workflow.event != "schedule";
+                    return found || !is_cron(workflow);
                 })) return;
                 if (remaining >= 0) {
                     next();
@@ -38,6 +38,10 @@ exports.should_stop = function(callback) {
     });
 };
 
+function is_cron(workflow) {
+    return /^(schedule|workflow_dispatch|workflow_run)$/.test(workflow.event);
+}
+
 function read(url, callback) {
     var done = function(reply) {
         done = function() {};
@@ -56,7 +60,7 @@ function read(url, callback) {
         }).on("end", function() {
             var reply;
             try {
-                reply = JSON.parse(chunks.join(""))
+                reply = JSON.parse(chunks.join(""));
             } catch (e) {}
             done(reply);
         }).on("error", function() {

test/ufuzz/index.js

@@ -334,6 +334,7 @@ var VAR_NAMES = [
     "arguments",
     "async",
     "await",
+    "let",
     "yield",
 ];
 var INITIAL_NAMES_LEN = VAR_NAMES.length;
@@ -352,10 +353,11 @@ var TYPEOF_OUTCOMES = [
 ];
 
 var avoid_vars = [];
-var block_vars = [];
+var block_vars = [ "let" ];
 var lambda_vars = [];
 var unique_vars = [];
 var classes = [];
+var allow_this = true;
 var async = false;
 var has_await = false;
 var export_default = false;
@@ -398,10 +400,11 @@ function mayDefer(code) {
 
 function createTopLevelCode() {
     VAR_NAMES.length = INITIAL_NAMES_LEN; // prune any previous names still in the list
-    block_vars.length = 0;
+    block_vars.length = 1;
     lambda_vars.length = 0;
     unique_vars.length = 0;
     classes.length = 0;
+    allow_this = true;
     async = false;
     has_await = false;
     export_default = false;
@@ -1731,6 +1734,8 @@ function createObjectFunction(recurmax, stmtDepth, canThrow, internal, isClazz)
         fn = function(defns) {
             if (generator) name = "*" + name;
             if (async) name = "async "+ name;
+            var save_allow = allow_this;
+            if (internal == "super") allow_this = false;
             s = [
                 name + "(" + createParams(save_async, save_generator, NO_DUPLICATE) + "){",
                 strictMode(),
@@ -1738,6 +1743,7 @@ function createObjectFunction(recurmax, stmtDepth, canThrow, internal, isClazz)
             ];
             s.push(_createStatements(2, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CANNOT_RETURN, stmtDepth));
             if (internal == "super") s.push("super" + createArgs(recurmax, stmtDepth, canThrow, NO_TEMPLATE) + ";");
+            allow_this = save_allow;
             if (/^(constructor|super)$/.test(internal) || rng(10) == 0) for (var i = rng(4); --i >= 0;) {
                 s.push(rng(2) ? createSuperAssignment(recurmax, stmtDepth, canThrow) : createThisAssignment(recurmax, stmtDepth, canThrow));
             }
@@ -1974,7 +1980,7 @@ function createValue() {
     var v;
     do {
         v = VALUES[rng(VALUES.length)];
-    } while (v == "new.target" && rng(200));
+    } while (v == "new.target" && rng(200) || !allow_this && v == "this");
     return v;
 }
 
@@ -2022,6 +2028,7 @@ function removeAvoidVar(name) {
 function isBannedKeyword(name) {
     switch (name) {
       case "arguments":
+      case "let":
         return in_class;
       case "await":
         return async !== false;
@@ -2073,8 +2080,8 @@ if (require.main !== module) {
     return;
 }
 
-function run_code(code, toplevel) {
+function run_code(code, toplevel, timeout) {
-    return sandbox.run_code(sandbox.patch_module_statements(code), toplevel);
+    return sandbox.run_code(sandbox.patch_module_statements(code), toplevel, timeout);
 }
 
 function writeln(stream, msg) {
@@ -2251,7 +2258,7 @@ function sort_globals(code) {
             return (typeof global[n] == "function") - (typeof global[m] == "function")
                 || (m < n ? -1 : m > n ? 1 : 0);
         };
-    } + "(this));" + code);
+    } + "(this));\n" + code);
     if (!Array.isArray(globals)) {
         errorln();
         errorln();
@@ -2289,6 +2296,20 @@ function fuzzy_match(original, uglified) {
     }
 }
 
+function patch_proto() {
+    [ Array, Boolean, Error, Function, Number, Object, RegExp, String ].forEach(function(type) {
+        [ "toString", "valueOf" ].forEach(function(prop) {
+            type.prototype[prop] = function(fn) {
+                return function() {
+                    try {
+                        return fn.apply(this, arguments);
+                    } catch (e) {}
+                };
+            }(type.prototype[prop]);
+        });
+    });
+}
+
 function is_error_timeout(ex) {
     return /timed out/.test(ex.message);
 }
@@ -2298,7 +2319,7 @@ function is_error_in(ex) {
 }
 
 function is_error_spread(ex) {
-    return ex.name == "TypeError" && /Found non-callable @@iterator| is not iterable| is not a function/.test(ex.message);
+    return ex.name == "TypeError" && /Found non-callable @@iterator| is not iterable| not a function/.test(ex.message);
 }
 
 function is_error_recursion(ex) {
@@ -2331,7 +2352,7 @@ function patch_try_catch(orig, toplevel) {
         tries: [],
     } ];
     var tail_throw = '\nif (typeof UFUZZ_ERROR == "object") throw UFUZZ_ERROR;\n';
-    var re = /(?:(?:^|[\s{}):;])try|}\s*catch\s*\(([^)[{]+)\)|}\s*finally)\s*(?={)/g;
+    var re = /(?:(?:^|[\s{}):;])try|}\s*catch\s*\(([^()[{]+)\)|}\s*finally)\s*(?={)/g;
     while (stack.length) {
         var code = stack[0].code;
         var offset = stack[0].offset;
@@ -2448,8 +2469,10 @@ for (var round = 1; round <= num_iterations; round++) {
         println("original result:");
         println(result);
         println();
-        // ignore v8 parser bug
+            // ignore v8 parser bug
-        return bug_async_arrow_rest(result);
+        return bug_async_arrow_rest(result)
+            // ignore runtime platform bugs
+            || result.message == "Script execution aborted.";
     })) continue;
     minify_options.forEach(function(options) {
         var o = JSON.parse(options);
@@ -2464,6 +2487,8 @@ for (var round = 1; round <= num_iterations; round++) {
             ok = sandbox.same_stdout(original_result, uglify_result);
             // ignore v8 parser bug
             if (!ok && bug_async_arrow_rest(uglify_result)) ok = true;
+            // ignore runtime platform bugs
+            if (!ok && uglify_result.message == "Script execution aborted.") ok = true;
             // handle difference caused by time-outs
             if (!ok && errored && is_error_timeout(original_result)) {
                 if (is_error_timeout(uglify_result)) {
@@ -2495,8 +2520,8 @@ for (var round = 1; round <= num_iterations; round++) {
             if (!ok && errored && uglify_result.name == "ReferenceError" && original_result.name == "ReferenceError") ok = true;
             // ignore difference due to implicit strict-mode in `class`
             if (!ok && /\bclass\b/.test(original_code)) {
-                var original_strict = run_code('"use strict";' + original_code, toplevel);
+                var original_strict = run_code('"use strict";\n' + original_code, toplevel);
-                var uglify_strict = run_code('"use strict";' + uglify_code, toplevel);
+                var uglify_strict = run_code('"use strict";\n' + uglify_code, toplevel);
                 if (typeof original_strict != "string") {
                     ok = typeof uglify_strict != "string";
                 } else {
@@ -2507,6 +2532,12 @@ for (var round = 1; round <= num_iterations; round++) {
             if (!ok && errored && /\bimport\b/.test(original_code)) {
                 if (is_error_redeclaration(uglify_result) && is_error_redeclaration(original_result)) ok = true;
             }
+            // ignore difference due to `__proto__` assignment
+            if (!ok && /\b__proto__\b/.test(original_code)) {
+                var original_proto = run_code("(" + patch_proto + ")();\n" + original_code, toplevel);
+                var uglify_proto = run_code("(" + patch_proto + ")();\n" + uglify_code, toplevel);
+                ok = sandbox.same_stdout(original_proto, uglify_proto);
+            }
             // 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

test/ufuzz/options.json

@@ -16,7 +16,7 @@
     },
     {},
     {
-        "ie8": true,
+        "ie": true,
         "toplevel": true
     },
     {