v3.15.5

fixes #5436

.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:

README.md

@@ -115,6 +115,7 @@ a double dash to prevent input files being used as option arguments:
                                 Equivalent to setting `ie: true` in `minify()`
                                 for `compress`, `mangle` and `output` options.
                                 By default UglifyJS will not try to be IE-proof.
+    --keep-fargs                Do not mangle/drop function arguments.
     --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.
@@ -504,6 +505,9 @@ if (result.error) throw result.error;
 
 - `ie` (default: `false`) — enable workarounds for Internet Explorer bugs.
 
+- `keep_fargs` (default: `false`) — pass `true` to prevent discarding or mangling
+  of function arguments.
+
 - `keep_fnames` (default: `false`) — pass `true` to prevent discarding or mangling
   of function names.  Useful for code relying on `Function.prototype.name`.
 
@@ -707,7 +711,8 @@ to be `false` and all symbol names will be omitted.
   - `1` — inline simple functions
   - `2` — inline functions with arguments
   - `3` — inline functions with arguments and variables
-  - `true` — same as `3`
+  - `4` — inline functions with arguments, variables and statements
+  - `true` — same as `4`
 
 - `join_vars` (default: `true`) — join consecutive `var` statements
 
@@ -867,6 +872,9 @@ UglifyJS.minify(code, { mangle: { toplevel: true } }).code;
 - `debug` (default: `false`) — Mangle names with the original name still present.
   Pass an empty string `""` to enable, or a non-empty string to set the debug suffix.
 
+- `keep_fargs` (default: `false`) — Use `true` to prevent mangling of function
+  arguments.
+
 - `keep_quoted` (default: `false`) — Only mangle unquoted property names.
 
 - `regex` (default: `null`) — Pass a RegExp literal to only mangle property
@@ -909,9 +917,11 @@ can pass additional arguments that control the code output:
 
 - `galio` (default: `false`) — enable workarounds for ANT Galio bugs
 
-- `indent_level` (default: `4`)
+- `indent_level` (default: `4`) — indent by specified number of spaces or the
+  exact whitespace sequence supplied, e.g. `"\t"`.
 
-- `indent_start` (default: `0`) — prefix all lines by that many spaces
+- `indent_start` (default: `0`) — prefix all lines by whitespace sequence
+  specified in the same format as `indent_level`.
 
 - `inline_script` (default: `true`) — escape HTML comments and the slash in
   occurrences of `</script>` in strings
@@ -1199,6 +1209,17 @@ 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
   ({
@@ -1352,3 +1373,19 @@ To allow for better optimizations, the compiler makes various assumptions:
   // TypeError: const 'a' has already been declared
   ```
   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
+  try {
+      class A {
+          static 42;
+          static get 42() {}
+      }
+      console.log("PASS");
+  } catch (e) {
+      console.log("FAIL");
+  }
+  // Expected: "PASS"
+  // Actual:   "FAIL"
+  ```
+  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 = {
@@ -70,6 +72,7 @@ function process_option(name, no_value) {
                 } else {
                     if (padding.length < name.length) padding = Array(name.length + 1).join(" ");
                     toplevels.push([ {
+                        keep_fargs: "keep-fargs",
                         keep_fnames: "keep-fnames",
                         nameCache: "name-cache",
                     }[name] || name, option ]);
@@ -102,6 +105,7 @@ function process_option(name, no_value) {
                 "  -d, --define <expr>[=value]              Global definitions.",
                 "  -e, --enclose [arg[,...][:value[,...]]]  Embed everything in a big function, with configurable argument(s) & value(s).",
                 "  --ie                                     Support non-standard Internet Explorer.",
+                "  --keep-fargs                             Do not mangle/drop function arguments.",
                 "  --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.",
@@ -158,6 +162,9 @@ function process_option(name, no_value) {
       case "no-annotations":
         options.annotations = false;
         break;
+      case "keep-fargs":
+        options.keep_fargs = true;
+        break;
       case "keep-fnames":
         options.keep_fnames = true;
         break;
@@ -430,7 +437,7 @@ 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) {
@@ -519,7 +526,7 @@ 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
@@ -559,8 +566,10 @@ function parse_js(value, options, flag) {
     return options;
 }
 
-function skip_key(key) {
-    return skip_keys.indexOf(key) >= 0;
+function skip_property(key, value) {
+    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

@@ -50,6 +50,8 @@ 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) {
@@ -135,6 +137,53 @@ var AST_Node = DEFNODE("Node", "start end", {
     },
 }, null);
 
+DEF_BITPROPS(AST_Node, [
+    "_optimized",
+    "_squeezed",
+    // AST_Call
+    "call_only",
+    // AST_Lambda
+    "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;
@@ -253,7 +302,7 @@ 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",
@@ -484,7 +533,7 @@ 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`",
@@ -543,13 +592,13 @@ 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) {
@@ -802,6 +851,9 @@ var AST_DefClass = DEFNODE("DefClass", null, {
     $propdoc: {
         name: "[AST_SymbolDefClass] the name of this class",
     },
+    resolve: function(def_class) {
+        return def_class ? this : this.parent_scope.resolve();
+    },
     _validate: function() {
         if (!(this.name instanceof AST_SymbolDefClass)) throw new Error("name must be AST_SymbolDefClass");
     },
@@ -1295,7 +1347,7 @@ var AST_Call = DEFNODE("Call", "args expression optional pure terminal", {
         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) {
@@ -1489,6 +1541,12 @@ var AST_Assign = DEFNODE("Assign", null, {
                     throw new Error("left must be assignable: " + node.TYPE);
                 }
             });
+        } else if (!(this.left instanceof AST_Infinity
+            || this.left instanceof AST_NaN
+            || this.left instanceof AST_PropAccess && !this.left.optional
+            || this.left instanceof AST_SymbolRef
+            || this.left instanceof AST_Undefined)) {
+            throw new Error("left must be assignable");
         }
     },
 }, AST_Binary);
@@ -1747,7 +1805,7 @@ 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);
 
@@ -1923,27 +1981,27 @@ var AST_Atom = DEFNODE("Atom", null, {
 
 var AST_Null = DEFNODE("Null", null, {
     $documentation: "The `null` atom",
-    value: null
+    value: null,
 }, AST_Atom);
 
 var AST_NaN = DEFNODE("NaN", null, {
     $documentation: "The impossible value",
-    value: 0/0
+    value: 0/0,
 }, AST_Atom);
 
 var AST_Undefined = DEFNODE("Undefined", null, {
     $documentation: "The `undefined` value",
-    value: function(){}()
+    value: function(){}(),
 }, AST_Atom);
 
 var AST_Hole = DEFNODE("Hole", null, {
     $documentation: "A hole in an array",
-    value: function(){}()
+    value: function(){}(),
 }, AST_Atom);
 
 var AST_Infinity = DEFNODE("Infinity", null, {
     $documentation: "The `Infinity` value",
-    value: 1/0
+    value: 1/0,
 }, AST_Atom);
 
 var AST_Boolean = DEFNODE("Boolean", null, {
@@ -1955,12 +2013,12 @@ var AST_Boolean = DEFNODE("Boolean", null, {
 
 var AST_False = DEFNODE("False", null, {
     $documentation: "The `false` atom",
-    value: false
+    value: false,
 }, AST_Boolean);
 
 var AST_True = DEFNODE("True", null, {
     $documentation: "The `true` atom",
-    value: true
+    value: true,
 }, AST_Boolean);
 
 /* -----[ TreeWalker ]----- */
@@ -1999,7 +2057,7 @@ 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;
         }
@@ -2030,33 +2088,40 @@ TreeWalker.prototype = {
         }
     },
     in_boolean_context: function() {
-        var self = this.self();
-        for (var i = 0, p; p = this.parent(i); i++) {
-            if (p instanceof AST_Conditional && p.condition === self
-                || p instanceof AST_DWLoop && p.condition === self
-                || p instanceof AST_For && p.condition === self
-                || p instanceof AST_If && p.condition === self
-                || p instanceof AST_Return && p.in_bool
-                || p instanceof AST_Sequence && p.tail_node() !== self
-                || p instanceof AST_SimpleStatement
-                || p instanceof AST_UnaryPrefix && p.operator == "!" && p.expression === self) {
-                return true;
-            }
-            if (p instanceof AST_Binary && (p.operator == "&&" || p.operator == "||")
-                || p instanceof AST_Conditional
-                || p.tail_node() === self) {
-                self = p;
-            } else if (p instanceof AST_Return) {
-                for (var call, fn = p; call = this.parent(++i); fn = call) {
-                    if (call.TYPE == "Call") {
-                        if (!(fn instanceof AST_Lambda) || fn.name) return false;
-                    } else if (fn instanceof AST_Lambda) {
-                        return false;
-                    }
-                }
-            } else {
+        for (var drop = true, level = 0, parent, self = this.self(); parent = this.parent(level++); self = parent) {
+            if (parent instanceof AST_Binary) switch (parent.operator) {
+              case "&&":
+              case "||":
+                if (parent.left === self) drop = false;
+                continue;
+              default:
                 return false;
             }
+            if (parent instanceof AST_Conditional) {
+                if (parent.condition === self) return true;
+                continue;
+            }
+            if (parent instanceof AST_DWLoop) return parent.condition === self;
+            if (parent instanceof AST_For) return parent.condition === self;
+            if (parent instanceof AST_If) return parent.condition === self;
+            if (parent instanceof AST_Return) {
+                if (parent.in_bool) return true;
+                while (parent = this.parent(level++)) {
+                    if (parent instanceof AST_Lambda) {
+                        if (parent.name) return false;
+                        parent = this.parent(level++);
+                        if (parent.TYPE != "Call") return false;
+                        break;
+                    }
+                }
+            }
+            if (parent instanceof AST_Sequence) {
+                if (parent.tail_node() === self) continue;
+                return drop ? "d" : true;
+            }
+            if (parent instanceof AST_SimpleStatement) return drop ? "d" : true;
+            if (parent instanceof AST_UnaryPrefix) return parent.operator == "!";
+            return false;
         }
     }
 };

lib/minify.js

@@ -28,7 +28,7 @@ function read_source_map(name, toplevel) {
         var match = /^# ([^\s=]+)=(\S+)\s*$/.exec(comment.value);
         if (!match) break;
         if (match[1] == "sourceMappingURL") {
-            match = /^data:application\/json(;.*?)?;base64,(\S+)$/.exec(match[2]);
+            match = /^data:application\/json(;.*?)?;base64,([^,]+)$/.exec(match[2]);
             if (!match) break;
             return to_ascii(match[2]);
         }
@@ -78,6 +78,7 @@ function minify(files, options) {
             enclose: false,
             ie: false,
             ie8: false,
+            keep_fargs: false,
             keep_fnames: false,
             mangle: {},
             nameCache: null,
@@ -95,20 +96,21 @@ function minify(files, options) {
         }, true);
         if (options.validate) AST_Node.enable_validation();
         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) 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, [ "compress", "mangle", "output" ]);
+        if (options.ie) set_shorthand("ie", options, [ "compress", "mangle", "output", "rename" ]);
+        if (options.keep_fargs) set_shorthand("keep_fargs", options, [ "compress", "mangle", "rename" ]);
+        if (options.keep_fnames) set_shorthand("keep_fnames", options, [ "compress", "mangle", "rename" ]);
+        if (options.toplevel) set_shorthand("toplevel", options, [ "compress", "mangle", "rename" ]);
+        if (options.v8) set_shorthand("v8", options, [ "mangle", "output", "rename" ]);
+        if (options.webkit) set_shorthand("webkit", options, [ "compress", "mangle", "output", "rename" ]);
         var quoted_props;
         if (options.mangle) {
             options.mangle = defaults(options.mangle, {
                 cache: options.nameCache && (options.nameCache.vars || {}),
                 eval: false,
                 ie: false,
+                keep_fargs: false,
                 keep_fnames: false,
                 properties: false,
                 reserved: [],
@@ -132,6 +134,7 @@ function minify(files, options) {
             init_cache(options.mangle.cache);
             init_cache(options.mangle.properties.cache);
         }
+        if (options.rename === undefined) options.rename = options.compress && options.mangle;
         if (options.sourceMap) {
             options.sourceMap = defaults(options.sourceMap, {
                 content: null,
@@ -187,8 +190,8 @@ function minify(files, options) {
         if (options.validate) toplevel.validate_ast();
         if (timings) timings.rename = Date.now();
         if (options.rename) {
-            toplevel.figure_out_scope(options.mangle);
-            toplevel.expand_names(options.mangle);
+            toplevel.figure_out_scope(options.rename);
+            toplevel.expand_names(options.rename);
         }
         if (timings) timings.compress = Date.now();
         if (options.compress) {

lib/mozilla-ast.js

@@ -1005,7 +1005,7 @@
     });
 
     def_to_moz(AST_RegExp, function To_Moz_RegExpLiteral(M) {
-        var flags = M.value.toString().match(/[gimuy]*$/)[0];
+        var flags = M.value.toString().match(/\/([gimuy]*)$/)[1];
         var value = "/" + M.value.raw_source + "/" + flags;
         return {
             type: "Literal",
@@ -1013,8 +1013,8 @@
             raw: value,
             regex: {
                 pattern: M.value.raw_source,
-                flags: flags
-            }
+                flags: flags,
+            },
         };
     });
 

lib/output.js

@@ -101,10 +101,18 @@ function OutputStream(options) {
         }
     }
 
+    function make_indent(value) {
+        if (typeof value == "number") return new Array(value + 1).join(" ");
+        if (!value) return "";
+        if (!/^\s*$/.test(value)) throw new Error("unsupported indentation: " + JSON.stringify("" + value));
+        return value;
+    }
+
     var current_col = 0;
     var current_line = 1;
-    var current_pos = 0;
-    var indentation = options.indent_start;
+    var current_indent = make_indent(options.indent_start);
+    var full_indent = make_indent(options.indent_level);
+    var half_indent = full_indent.length + 1 >> 1;
     var last;
     var line_end = 0;
     var line_fixed = true;
@@ -115,17 +123,17 @@ function OutputStream(options) {
     var might_need_semicolon;
     var need_newline_indented = false;
     var need_space = false;
-    var newline_insert = -1;
+    var output;
     var stack;
-    var OUTPUT;
+    var stored = "";
 
     function reset() {
         last = "";
         might_need_space = false;
         might_need_semicolon = false;
         stack = [];
-        var str = OUTPUT;
-        OUTPUT = "";
+        var str = output;
+        output = "";
         return str;
     }
 
@@ -227,32 +235,30 @@ function OutputStream(options) {
     } : noop;
 
     function insert_newlines(count) {
-        var index = OUTPUT.lastIndexOf("\n");
-        if (line_end < index) line_end = index;
-        var left = OUTPUT.slice(0, line_end);
-        var right = OUTPUT.slice(line_end);
-        adjust_mappings(count, right.length - current_col);
+        stored += output.slice(0, line_end);
+        output = output.slice(line_end);
+        var new_col = output.length;
+        adjust_mappings(count, new_col - current_col);
         current_line += count;
-        current_pos += count;
-        current_col = right.length;
-        OUTPUT = left;
-        while (count--) OUTPUT += "\n";
-        OUTPUT += right;
+        current_col = new_col;
+        while (count--) stored += "\n";
     }
 
-    var fix_line = options.max_line_len ? function() {
+    var fix_line = options.max_line_len ? function(flush) {
         if (line_fixed) {
             if (current_col > options.max_line_len) {
                 AST_Node.warn("Output exceeds {max_line_len} characters", options);
             }
             return;
         }
-        if (current_col > options.max_line_len) insert_newlines(1);
-        line_fixed = true;
-        flush_mappings();
+        if (current_col > options.max_line_len) {
+            insert_newlines(1);
+            line_fixed = true;
+        }
+        if (line_fixed || flush) flush_mappings();
     } : noop;
 
-    var requireSemicolonChars = makePredicate("( [ + * / - , .");
+    var require_semicolon = makePredicate("( [ + * / - , .");
 
     var print = options.beautify
         || options.comments
@@ -276,32 +282,32 @@ function OutputStream(options) {
                 space();
             }
         }
-        newline_insert = -1;
         var prev = last.slice(-1);
         if (might_need_semicolon) {
             might_need_semicolon = false;
-
-            if (prev == ":" && ch == "}" || (!ch || ";}".indexOf(ch) < 0) && prev != ";") {
-                if (options.semicolons || requireSemicolonChars[ch]) {
-                    OUTPUT += ";";
+            if (prev == ":" && ch == "}" || prev != ";" && (!ch || ";}".indexOf(ch) < 0)) {
+                var need_semicolon = require_semicolon[ch];
+                if (need_semicolon || options.semicolons) {
+                    output += ";";
                     current_col++;
-                    current_pos++;
+                    if (!line_fixed) {
+                        fix_line();
+                        if (line_fixed && !need_semicolon && output == ";") {
+                            output = "";
+                            current_col = 0;
+                        }
+                    }
+                    if (line_end == output.length - 1) line_end++;
                 } else {
                     fix_line();
-                    OUTPUT += "\n";
-                    current_pos++;
+                    output += "\n";
                     current_line++;
                     current_col = 0;
-
-                    if (/^\s+$/.test(str)) {
-                        // reset the semicolon flag, since we didn't print one
-                        // now and might still have to later
-                        might_need_semicolon = true;
-                    }
+                    // reset the semicolon flag, since we didn't print one
+                    // now and might still have to later
+                    if (/^\s+$/.test(str)) might_need_semicolon = true;
                 }
-
-                if (!options.beautify)
-                    might_need_space = false;
+                if (!options.beautify) might_need_space = false;
             }
         }
 
@@ -312,9 +318,8 @@ function OutputStream(options) {
                 || str == "--" && last == "!"
                 || str == "in" && prev == "/"
                 || last == "--" && ch == ">") {
-                OUTPUT += " ";
+                output += " ";
                 current_col++;
-                current_pos++;
             }
             if (prev != "<" || str != "!") might_need_space = false;
         }
@@ -324,14 +329,13 @@ function OutputStream(options) {
                 token: mapping_token,
                 name: mapping_name,
                 line: current_line,
-                col: current_col
+                col: current_col,
             });
             mapping_token = false;
             if (line_fixed) flush_mappings();
         }
 
-        OUTPUT += str;
-        current_pos += str.length;
+        output += str;
         var a = str.split(/\r?\n/), n = a.length - 1;
         current_line += n;
         current_col += a[0].length;
@@ -346,7 +350,7 @@ function OutputStream(options) {
         if (might_need_semicolon) {
             might_need_semicolon = false;
             if (prev == ":" && ch == "}" || (!ch || ";}".indexOf(ch) < 0) && prev != ";") {
-                OUTPUT += ";";
+                output += ";";
                 might_need_space = false;
             }
         }
@@ -357,11 +361,11 @@ function OutputStream(options) {
                 || str == "--" && last == "!"
                 || str == "in" && prev == "/"
                 || last == "--" && ch == ">") {
-                OUTPUT += " ";
+                output += " ";
             }
             if (prev != "<" || str != "!") might_need_space = false;
         }
-        OUTPUT += str;
+        output += str;
         last = str;
     };
 
@@ -373,30 +377,25 @@ function OutputStream(options) {
 
     var indent = options.beautify ? function(half) {
         if (need_newline_indented) print("\n");
-        print(repeat_string(" ", half ? indentation - (options.indent_level >> 1) : indentation));
+        print(half ? current_indent.slice(0, -half_indent) : current_indent);
     } : noop;
 
     var with_indent = options.beautify ? function(cont) {
-        var save_indentation = indentation;
-        indentation += options.indent_level;
+        var save_indentation = current_indent;
+        current_indent += full_indent;
         cont();
-        indentation = save_indentation;
+        current_indent = save_indentation;
     } : function(cont) { cont() };
 
     var may_add_newline = options.max_line_len || options.preserve_line ? function() {
         fix_line();
-        line_end = OUTPUT.length;
+        line_end = output.length;
         line_fixed = false;
     } : noop;
 
     var newline = options.beautify ? function() {
-        if (newline_insert < 0) return print("\n");
-        if (OUTPUT[newline_insert] != "\n") {
-            OUTPUT = OUTPUT.slice(0, newline_insert) + "\n" + OUTPUT.slice(newline_insert);
-            current_pos++;
-            current_line++;
-        }
-        newline_insert++;
+        print("\n");
+        line_end = output.length;
     } : may_add_newline;
 
     var semicolon = options.beautify ? function() {
@@ -452,13 +451,12 @@ function OutputStream(options) {
     } : noop;
 
     function get() {
-        if (!line_fixed) fix_line();
-        return OUTPUT;
+        if (!line_fixed) fix_line(true);
+        return stored + output;
     }
 
     function has_nlb() {
-        var index = OUTPUT.lastIndexOf("\n");
-        return /^ *$/.test(OUTPUT.slice(index + 1));
+        return /(^|\n) *$/.test(output);
     }
 
     function pad_comment(token, force) {
@@ -515,15 +513,13 @@ function OutputStream(options) {
             scan.walk(tw);
         }
 
-        if (current_pos == 0) {
+        if (current_line == 1 && current_col == 0) {
             if (comments.length > 0 && options.shebang && comments[0].type == "comment5") {
                 print("#!" + comments.shift().value + "\n");
                 indent();
             }
             var preamble = options.preamble;
-            if (preamble) {
-                print(preamble.replace(/\r\n?|[\n\u2028\u2029]|\s*$/g, "\n"));
-            }
+            if (preamble) print(preamble.replace(/\r\n?|\u2028|\u2029|(^|\S)\s*$/g, "$1\n"));
         }
 
         comments = comments.filter(comment_filter, node);
@@ -561,20 +557,18 @@ function OutputStream(options) {
             return !/comment[134]/.test(c.type);
         }))) return;
         comments._dumped = self;
-        var insert = OUTPUT.length;
         comments.filter(comment_filter, node).forEach(function(comment, index) {
             pad_comment(comment, index || !tail);
             print_comment(comment);
         });
-        if (OUTPUT.length > insert) newline_insert = insert;
     }
 
     return {
         get             : get,
         reset           : reset,
         indent          : indent,
-        should_break    : options.width ? function() {
-            return current_col - indentation >= options.width;
+        should_break    : options.beautify && options.width ? function() {
+            return current_col >= options.width;
         } : return_false,
         has_parens      : function() { return last.slice(-1) == "(" },
         newline         : newline,
@@ -1152,8 +1146,9 @@ function OutputStream(options) {
         });
     }
     function print_arrow(self, output) {
-        if (self.argnames.length == 1 && self.argnames[0] instanceof AST_SymbolFunarg && !self.rest) {
-            self.argnames[0].print(output);
+        var argname = self.argnames.length == 1 && !self.rest && self.argnames[0];
+        if (argname instanceof AST_SymbolFunarg && argname.name != "yield") {
+            argname.print(output);
         } else {
             print_funargs(self, output);
         }
@@ -1464,7 +1459,7 @@ 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) {
@@ -1869,8 +1864,8 @@ function OutputStream(options) {
             len = match[0].length;
             digits = str.slice(len);
             candidates.push(digits + "e-" + (digits.length + len - 1));
-        } else if (match = /0+$/.exec(str)) {
-            len = match[0].length;
+        } else if (match = /[^0]0+$/.exec(str)) {
+            len = match[0].length - 1;
             candidates.push(str.slice(0, -len) + "e" + len);
         } else if (match = /^(\d)\.(\d+)e(-?\d+)$/.exec(str)) {
             candidates.push(match[1] + match[2] + "e" + (match[3] - match[2].length));

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(" ");
@@ -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;
@@ -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");
@@ -1186,19 +1194,19 @@ function parse($TEXT, options) {
     }
 
     function for_() {
-        var await = is("name", "await") && next();
+        var await_token = is("name", "await") && next();
         expect("(");
         var init = null;
-        if (await || !is("punc", ";")) {
+        if (await_token || !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))
                 : expression(true);
             var ctor;
-            if (await) {
+            if (await_token) {
                 expect_token("name", "of");
                 ctor = AST_ForAwaitOf;
             } else if (is("operator", "in")) {
@@ -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");
     }
 
@@ -1535,12 +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();
@@ -1555,11 +1574,6 @@ function parse($TEXT, options) {
             if (!is("operator", "*")) return function_(AST_Defun);
             next();
             return function_(AST_GeneratorDefun);
-          case "let":
-            next();
-            var node = let_();
-            semicolon();
-            return node;
           case "var":
             next();
             var node = var_();
@@ -1720,6 +1734,11 @@ function parse($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(),
@@ -2130,7 +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");
     }
 
@@ -2297,9 +2316,8 @@ function parse($TEXT, options) {
             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 (match) {
-                    expr.pure = match[0];
+                if (/[@#]__PURE__/.test(comments[i].value)) {
+                    expr.pure = true;
                     break;
                 }
             }

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 unmangleable = Object.create(reserved);
+    var names_to_mangle = new Dictionary();
+    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 (!should_mangle(name)) unmangleable[name] = true;
+        if (can_mangle(name)) names_to_mangle.set(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 = {
@@ -92,18 +92,35 @@ SymbolDef.prototype = {
         if (def && def !== self) return def.redefined() || def;
     },
     unmangleable: function(options) {
-        return this.global && !options.toplevel
-            || this.exported
-            || this.undeclared
-            || !options.eval && this.scope.pinned()
-            || options.keep_fnames
-                && (this.orig[0] instanceof AST_SymbolClass
-                    || this.orig[0] instanceof AST_SymbolDefClass
-                    || this.orig[0] instanceof AST_SymbolDefun
-                    || this.orig[0] instanceof AST_SymbolLambda);
+        if (this.exported) return true;
+        if (this.undeclared) return true;
+        if (!options.eval && this.scope.pinned()) return true;
+        if (options.keep_fargs && is_funarg(this)) return true;
+        if (options.keep_fnames) {
+            var sym = this.orig[0];
+            if (sym instanceof AST_SymbolClass) return true;
+            if (sym instanceof AST_SymbolDefClass) return true;
+            if (sym instanceof AST_SymbolDefun) return true;
+            if (sym instanceof AST_SymbolLambda) return true;
+        }
+        if (!options.toplevel && this.global) return true;
+        return false;
     },
 };
 
+DEF_BITPROPS(SymbolDef, [
+    "const_redefs",
+    "cross_loop",
+    "direct_access",
+    "exported",
+    "global",
+    "undeclared",
+]);
+
+function is_funarg(def) {
+    return def.orig[0] instanceof AST_SymbolFunarg || def.orig[1] instanceof AST_SymbolFunarg;
+}
+
 var unary_side_effects = makePredicate("delete ++ --");
 
 function is_lhs(node, parent) {
@@ -205,20 +222,17 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         } else if (node instanceof AST_SymbolDefun) {
             var def = defun.def_function(node, tw.parent());
             if (exported) def.exported = true;
-            entangle(defun, scope);
         } else if (node instanceof AST_SymbolFunarg) {
             defun.def_variable(node);
-            entangle(defun, scope);
         } else if (node instanceof AST_SymbolLambda) {
             var def = defun.def_function(node, node.name == "arguments" ? undefined : defun);
-            if (options.ie) def.defun = defun.parent_scope.resolve();
+            if (options.ie && node.name != "arguments") def.defun = defun.parent_scope.resolve();
         } else if (node instanceof AST_SymbolLet) {
             var def = scope.def_variable(node);
             if (exported) def.exported = true;
         } else if (node instanceof AST_SymbolVar) {
             var def = defun.def_variable(node, node instanceof AST_SymbolImport ? undefined : null);
             if (exported) def.exported = true;
-            entangle(defun, scope);
         }
 
         function walk_scope(descend) {
@@ -231,16 +245,6 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             scope = save_scope;
             defun = save_defun;
         }
-
-        function entangle(defun, scope) {
-            if (defun === scope) return;
-            node.mark_enclosed(options);
-            var def = scope.find_variable(node.name);
-            if (node.thedef === def) return;
-            node.thedef = def;
-            def.orig.push(node);
-            node.mark_enclosed(options);
-        }
     });
     self.make_def = function(orig, init) {
         return new SymbolDef(++next_def_id, this, orig, init);
@@ -261,6 +265,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         }
         if (node instanceof AST_Lambda) {
             in_arg.push(node);
+            if (node.name) node.name.walk(tw);
             node.argnames.forEach(function(argname) {
                 argname.walk(tw);
             });
@@ -287,6 +292,16 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
                 // ensure compression works if `const` reuses a scope variable
                 var redef = def.redefined();
                 if (redef) redef.const_redefs = true;
+            } else if (def.scope !== node.scope && (node instanceof AST_SymbolDefun
+                || node instanceof AST_SymbolFunarg
+                || node instanceof AST_SymbolVar)) {
+                node.mark_enclosed(options);
+                var redef = node.scope.find_variable(node.name);
+                if (node.thedef !== redef) {
+                    node.thedef = redef;
+                    redef.orig.push(node);
+                    node.mark_enclosed(options);
+                }
             }
             if (node.name != "arguments") return true;
             var parent = node instanceof AST_SymbolVar && tw.parent();
@@ -363,7 +378,7 @@ 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) {
@@ -454,6 +469,7 @@ AST_Lambda.DEFMETHOD("init_vars", function(parent_scope) {
     this.uses_arguments = false;
     this.def_variable(new AST_SymbolFunarg({
         name: "arguments",
+        scope: this,
         start: this.start,
         end: this.end,
     }));
@@ -465,9 +481,12 @@ 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;
-        } else if (options.keep_fnames) {
-            s.functions.each(function(d) {
+            s._var_names = undefined;
+        } else {
+            if (options.keep_fargs && s instanceof AST_Lambda) s.each_argname(function(arg) {
+                push_uniq(def.scope.enclosed, arg.definition());
+            });
+            if (options.keep_fnames) s.functions.each(function(d) {
                 push_uniq(def.scope.enclosed, d);
             });
         }
@@ -510,12 +529,12 @@ 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);
             }
         });
     }
@@ -526,34 +545,33 @@ 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) {
-                for (var name in names_in_use(scope, options)) {
-                    names[name] = true;
-                }
-                scopes.push(scope);
-            } else break;
+            if (member(scope, scopes)) break;
+            names_in_use(scope, options).each(function(marker, name) {
+                names.set(name, marker);
+            });
+            scopes.push(scope);
         } 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 (!names[name]) break;
+        if (in_use.has(name) || RESERVED_WORDS[name] || options.reserved.has[name]) continue;
+        if (!names.has(name)) break;
         holes.push(scope.cname);
     }
-    in_use[name] = true;
+    in_use.set(name, true);
     return name;
 }
 
@@ -573,6 +591,7 @@ function _default_mangler_options(options) {
     options = defaults(options, {
         eval        : false,
         ie          : false,
+        keep_fargs  : false,
         keep_fnames : false,
         reserved    : [],
         toplevel    : false,
@@ -580,32 +599,30 @@ function _default_mangler_options(options) {
         webkit      : false,
     });
     if (!Array.isArray(options.reserved)) options.reserved = [];
-    // Never mangle arguments
+    // Never mangle `arguments`
     push_uniq(options.reserved, "arguments");
     options.reserved.has = makePredicate(options.reserved);
     return options;
 }
 
+// We only need to mangle declaration nodes. Special logic wired into the code
+// generator will display the mangled name if it is present (and for
+// `AST_SymbolRef`s it will use the mangled name of the `AST_SymbolDeclaration`
+// that it points to).
 AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
     options = _default_mangler_options(options);
-
-    // We only need to mangle declaration nodes.  Special logic wired
-    // into the code generator will display the mangled name if it's
-    // present (and for AST_SymbolRef-s it'll use the mangled name of
-    // the AST_SymbolDeclaration that it points to).
-    var lname = -1;
-
     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);
         });
     }
-
+    var cutoff = 36;
+    var lname = -1;
     var redefined = [];
     var tw = new TreeWalker(function(node, descend) {
         if (node instanceof AST_LabeledStatement) {
-            // lname is incremented when we get to the AST_Label
+            // `lname` is incremented when we get to the `AST_Label`
             var save_nesting = lname;
             descend();
             if (!options.v8 || !in_label(tw)) lname = save_nesting;
@@ -627,9 +644,9 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
                     });
                 }, true);
             }
-            node.to_mangle = [];
+            var to_mangle = node.to_mangle = [];
             node.variables.each(function(def) {
-                if (!defer_redef(def)) node.to_mangle.push(def);
+                if (!defer_redef(def)) to_mangle.push(def);
             });
             descend();
             if (options.cache && node instanceof AST_Toplevel) {
@@ -640,7 +657,23 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
                 sym.scope = node;
                 sym.reference(options);
             }
-            node.to_mangle.forEach(mangle);
+            if (to_mangle.length > cutoff) {
+                var indices = to_mangle.map(function(def, index) {
+                    return index;
+                }).sort(function(i, j) {
+                    return to_mangle[j].references.length - to_mangle[i].references.length || i - j;
+                });
+                to_mangle = indices.slice(0, cutoff).sort(function(i, j) {
+                    return i - j;
+                }).map(function(index) {
+                    return to_mangle[index];
+                }).concat(indices.slice(cutoff).sort(function(i, j) {
+                    return i - j;
+                }).map(function(index) {
+                    return to_mangle[index];
+                }));
+            }
+            to_mangle.forEach(mangle);
             return true;
         }
         if (node instanceof AST_Label) {

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)) {
-            map[name] = array.length;
+        var index = map.get(name);
+        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)) {
-                sources_content[source] = content;
+            if (!sources_content.has(source)) {
+                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

@@ -55,14 +55,6 @@ function find_if(func, array) {
     for (var i = array.length; --i >= 0;) if (func(array[i])) return array[i];
 }
 
-function repeat_string(str, i) {
-    if (i <= 0) return "";
-    if (i == 1) return str;
-    var d = repeat_string(str, i >> 1);
-    d += d;
-    return i & 1 ? d + str : d;
-}
-
 function configure_error_stack(fn) {
     Object.defineProperty(fn.prototype, "stack", {
         get: function() {
@@ -96,15 +88,6 @@ 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 +126,7 @@ 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 +154,80 @@ function all(array, predicate) {
 }
 
 function Dictionary() {
-    this._values = Object.create(null);
-    this._size = 0;
+    this.values = Object.create(null);
 }
 Dictionary.prototype = {
     set: function(key, val) {
-        if (!this.has(key)) ++this._size;
-        this._values["$" + key] = val;
+        if (key == "__proto__") {
+            this.proto_value = val;
+        } else {
+            this.values[key] = val;
+        }
         return this;
     },
     add: function(key, val) {
-        if (this.has(key)) {
-            this.get(key).push(val);
+        var list = this.get(key);
+        if (list) {
+            list.push(val);
         } else {
             this.set(key, [ val ]);
         }
         return this;
     },
-    get: function(key) { return this._values["$" + key] },
+    get: function(key) {
+        return key == "__proto__" ? this.proto_value : this.values[key];
+    },
     del: function(key) {
-        if (this.has(key)) {
-            --this._size;
-            delete this._values["$" + key];
+        if (key == "__proto__") {
+            delete this.proto_value;
+        } else {
+            delete this.values[key];
         }
         return this;
     },
-    has: function(key) { return ("$" + 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)
-            if (!predicate(this._values[i], i.substr(1)))
-                return false;
+        for (var i in this.values)
+            if (!predicate(this.values[i], i)) 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)
-            f(this._values[i], i.substr(1));
+        for (var i in this.values)
+            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)
-            ret.push(f(this._values[i], i.substr(1)));
+        for (var i in this.values)
+            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)
-            ret._values[i] = this._values[i];
-        ret._size = this._size;
+        this.each(function(value, i) {
+            ret.set(i, value);
+        });
         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 +265,21 @@ 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": "3.14.2",
+  "version": "3.15.5",
   "engines": {
     "node": ">=0.8.0"
   },

test/benchmark.js

@@ -17,6 +17,7 @@ var urls = [
     "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/d3/6.7.0/d3.js",
+    "https://cdnjs.cloudflare.com/ajax/libs/antd/4.18.7/antd.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.js

@@ -183,13 +183,11 @@ function parse_test(file) {
 function reminify(orig_options, input_code, input_formatted, stdout) {
     for (var i = 0; i < minify_options.length; i++) {
         var options = JSON.parse(minify_options[i]);
-        if (options.compress) [
+        [
             "keep_fargs",
             "keep_fnames",
         ].forEach(function(name) {
-            if (name in orig_options) {
-                options.compress[name] = orig_options[name];
-            }
+            if (name in orig_options) options[name] = orig_options[name];
         });
         var options_formatted = JSON.stringify(options, null, 4);
         options.validate = true;

test/compress/annotations.js

@@ -442,9 +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/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,
     }
@@ -486,7 +508,7 @@ drop_value: {
         ((a, b) => a + b)(console.log(42));
     }
     expect: {
-        ((a, b) => {})(console.log(42));
+        void console.log(42);
     }
     expect_stdout: "42"
     node_version: ">=4"
@@ -884,3 +906,203 @@ issue_4772: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_5251: {
+    options = {
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        (() => {
+            while (console.log(arguments))
+                var arguments = "FAIL";
+        })();
+    }
+    expect: {
+        (() => {
+            while (console.log(arguments))
+                var arguments = "FAIL";
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+issue_5342_1: {
+    options = {
+        dead_code: true,
+        inline: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        for (var a in 0) {
+            (() => {
+                while (1);
+            })(new function(NaN) {
+                a.p;
+            }());
+        }
+        console.log(function() {
+            return b;
+            try {
+                b;
+            } catch (e) {
+                var b;
+            }
+        }());
+    }
+    expect: {
+        for (var a in 0) {
+            (function(NaN) {
+                a.p;
+            })();
+            while (1);
+        }
+        console.log(b);
+        var b;
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}
+
+issue_5342_2: {
+    rename = true
+    options = {
+        dead_code: true,
+        inline: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        for (var a in 0) {
+            (() => {
+                while (1);
+            })(new function(NaN) {
+                a.p;
+            }());
+        }
+        console.log(function() {
+            return b;
+            try {
+                b;
+            } catch (e) {
+                var b;
+            }
+        }());
+    }
+    expect: {
+        for (var a in 0) {
+            a.p;
+            while (1);
+        }
+        console.log(c);
+        var c;
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}
+
+issue_5356: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log((a => a++)(console));
+    }
+    expect: {
+        console.log((a => +a)(console));
+    }
+    expect_stdout: "NaN"
+    node_version: ">=4"
+}
+
+issue_5414_1: {
+    options = {
+        arrows: true,
+        if_return: true,
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        (() => {
+            (() => {
+                if (!console)
+                    var arguments = 42;
+                while (console.log(arguments));
+            })();
+        })();
+    }
+    expect: {
+        (() => {
+            if (!console)
+                var arguments = 42;
+            while (console.log(arguments));
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+issue_5414_2: {
+    options = {
+        arrows: true,
+        inline: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        (() => {
+            (() => {
+                if (!console)
+                    var arguments = 42;
+                while (console.log(arguments));
+            })();
+        })();
+    }
+    expect: {
+        (() => {
+            if (!console)
+                var arguments = 42;
+            while (console.log(arguments));
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+issue_5416: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        inline: true,
+        loops: true,
+        unused: true,
+    }
+    input: {
+        var f = () => {
+            while ((() => {
+                console;
+                var a = function g(arguments) {
+                    console.log(arguments);
+                }();
+            })());
+        };
+        f();
+    }
+    expect: {
+        var f = () => {
+            {
+                arguments = void 0;
+                console;
+                console.log(arguments);
+                var arguments;
+            }
+        };
+        f();
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}

test/compress/assignments.js

@@ -489,7 +489,7 @@ logical_assignments: {
     node_version: ">=15"
 }
 
-logical_collapse_vars: {
+logical_collapse_vars_1: {
     options = {
         collapse_vars: true,
     }
@@ -509,6 +509,46 @@ logical_collapse_vars: {
     node_version: ">=15"
 }
 
+logical_collapse_vars_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "PASS";
+        (function(b) {
+            b ||= (a = "FAIL", {});
+            return b;
+        })(console).log(a);
+    }
+    expect: {
+        var a = "PASS";
+        (function(b) {
+            return b ||= (a = "FAIL", {});
+        })(console).log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+logical_collapse_vars_3: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = 6;
+        a *= 7;
+        a ??= "FAIL";
+        console.log(a);
+    }
+    expect: {
+        var a = 6;
+        a = a * 7 ?? "FAIL";
+        console.log(a);
+    }
+    expect_stdout: "42"
+    node_version: ">=15"
+}
+
 logical_reduce_vars: {
     options = {
         evaluate: true,
@@ -550,6 +590,24 @@ 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,
@@ -615,8 +673,7 @@ issue_4827_1: {
         c &&= b = a, console.log(b);
     }
     expect: {
-        A = "FAIL";
-        var a = A, b = "PASS", c;
+        var a = A = "FAIL", b = "PASS", c;
         c &&= b = a, console.log(b);
     }
     expect_stdout: "PASS"

test/compress/awaits.js

@@ -11,6 +11,21 @@ async_arrow: {
     node_version: ">=8"
 }
 
+async_computed: {
+    input: {
+        var o = {
+            async [42]() {
+                return this.p;
+            },
+            p: "PASS",
+        };
+        o[42]().then(console.log);
+    }
+    expect_exact: 'var o={async[42](){return this.p},p:"PASS"};o[42]().then(console.log);'
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
 async_label: {
     input: {
         (async function() {
@@ -182,6 +197,34 @@ dont_inline: {
     node_version: ">=8"
 }
 
+dont_inline_nested: {
+    options = {
+        inline: true,
+    }
+    input: {
+        function await() {
+            return "PASS";
+        }
+        (async function() {
+            (function() {
+                console.log(await("FAIL"));
+            })();
+        })();
+    }
+    expect: {
+        function await() {
+            return "PASS";
+        }
+        (async function() {
+            (function() {
+                console.log(await("FAIL"));
+            })();
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
 inline_await_1: {
     options = {
         awaits: true,
@@ -340,7 +383,436 @@ inline_await_3_trim: {
     node_version: ">=8"
 }
 
-await_unary: {
+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"
+}
+
+inline_block: {
+    options = {
+        awaits: true,
+        if_return: true,
+        inline: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            (async function() {
+                for (var a of [ "baz" ])
+                    return a;
+            })();
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            for (var a of [ "baz" ])
+                return void await a;
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+        "undefined",
+    ]
+    node_version: ">=8"
+}
+
+inline_block_async: {
+    options = {
+        awaits: true,
+        if_return: true,
+        inline: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            (async function() {
+                for (var a of [ "baz" ])
+                    return {
+                        then(r) {
+                            console.log("moo");
+                            r(a);
+                        },
+                    };
+            })();
+        })().then(console.log);
+        console.log("moz");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            for (var a of [ "baz" ])
+                return void await {
+                    then(r) {
+                        console.log("moo");
+                        r(a);
+                    },
+                };
+        })().then(console.log);
+        console.log("moz");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moz",
+        "moo",
+        "undefined",
+    ]
+    node_version: ">=8"
+}
+
+inline_block_await: {
+    options = {
+        awaits: true,
+        if_return: true,
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            await async function() {
+                for (var a of [ "baz" ])
+                    return a;
+            }();
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            for (var a of [ "baz" ])
+                return void await a;
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+        "undefined",
+    ]
+    node_version: ">=8"
+}
+
+inline_block_await_async: {
+    options = {
+        inline: true,
+    }
+    input: {
+        (async function() {
+            console.log("foo");
+            await (async function() {
+                while (await console.log("bar"));
+                console.log("baz");
+            })();
+            console.log("moo");
+        })().then(console.log);
+        console.log("moz");
+    }
+    expect: {
+        (async function() {
+            console.log("foo");
+            while (await console.log("bar"));
+            console.log("baz");
+            await 0;
+            console.log("moo");
+        })().then(console.log);
+        console.log("moz");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moz",
+        "baz",
+        "moo",
+        "undefined",
+    ]
+    node_version: ">=8"
+}
+
+inline_block_await_async_return: {
+    options = {
+        awaits: true,
+        if_return: true,
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            await async function() {
+                for (var a of [ "baz" ])
+                    return {
+                        then(r) {
+                            console.log("moo");
+                            r(a);
+                        },
+                    };
+            }();
+        })().then(console.log);
+        console.log("moz");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            for (var a of [ "baz" ])
+                return void await {
+                    then(r) {
+                        console.log("moo");
+                        r(a);
+                    },
+                };;
+        })().then(console.log);
+        console.log("moz");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moz",
+        "moo",
+        "undefined",
+    ]
+    node_version: ">=8"
+}
+
+inline_block_return: {
+    options = {
+        awaits: true,
+        if_return: true,
+        inline: true,
+        passes: 2,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            return async function() {
+                for (var a of [ "baz" ])
+                    return a;
+            }();
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            for (var a of [ "baz" ])
+                return a;
+        })().then(console.log);
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+        "baz",
+    ]
+    node_version: ">=8"
+}
+
+inline_block_return_async: {
+    options = {
+        awaits: true,
+        if_return: true,
+        inline: true,
+        passes: 2,
+        side_effects: true,
+    }
+    input: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            return async function() {
+                for (var a of [ "baz" ])
+                    return {
+                        then(r) {
+                            console.log("moo");
+                            r(a);
+                        },
+                    };
+            }();
+        })().then(console.log);
+        console.log("moz");
+    }
+    expect: {
+        console.log("foo");
+        (async function() {
+            console.log("bar");
+            for (var a of [ "baz" ])
+                return {
+                    then(r) {
+                        console.log("moo");
+                        r(a);
+                    },
+                };
+        })().then(console.log);
+        console.log("moz");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moz",
+        "moo",
+        "baz",
+    ]
+    node_version: ">=8"
+}
+
+await_then: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        var a = "PASS";
+        function f() {
+            return {
+                then: function(r) {
+                    a = "FAIL";
+                    r();
+                },
+            };
+        }
+        (async function() {
+            f(), await 42;
+            while (console.log(a));
+        })();
+    }
+    expect: {
+        var a = "PASS";
+        function f() {
+            return {
+                then: function(r) {
+                    a = "FAIL";
+                    r();
+                },
+            };
+        }
+        (async function() {
+            await !f();
+            while (console.log(a));
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+await_unary_1: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        var a = "PASS";
+        function f() {
+            return {
+                then: function(r) {
+                    a = "FAIL";
+                    r();
+                },
+            };
+        }
+        (async function() {
+            await !f();
+            while (console.log(a));
+        })();
+    }
+    expect: {
+        var a = "PASS";
+        function f() {
+            return {
+                then: function(r) {
+                    a = "FAIL";
+                    r();
+                },
+            };
+        }
+        (async function() {
+            await !f();
+            while (console.log(a));
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+await_unary_2: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        var a = "PASS";
+        function f() {
+            return {
+                then: function(r) {
+                    a = "FAIL";
+                    r();
+                },
+            };
+        }
+        (async function() {
+            await ~f();
+            while (console.log(a));
+        })();
+    }
+    expect: {
+        var a = "PASS";
+        function f() {
+            return {
+                then: function(r) {
+                    a = "FAIL";
+                    r();
+                },
+            };
+        }
+        (async function() {
+            await !f();
+            while (console.log(a));
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+await_unary_3: {
     options = {
         awaits: true,
         side_effects: true,
@@ -367,7 +839,46 @@ await_unary: {
     node_version: ">=8"
 }
 
-await_void: {
+await_void_1: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        var a = "PASS";
+        function f() {
+            return {
+                then: function(r) {
+                    a = "FAIL";
+                    r();
+                },
+            };
+        }
+        (async function() {
+            await void f();
+            while (console.log(a));
+        })();
+    }
+    expect: {
+        var a = "PASS";
+        function f() {
+            return {
+                then: function(r) {
+                    a = "FAIL";
+                    r();
+                },
+            };
+        }
+        (async function() {
+            await !f();
+            while (console.log(a));
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+await_void_2: {
     options = {
         awaits: true,
         if_return: true,
@@ -382,7 +893,7 @@ await_void: {
     }
     expect: {
         (async function() {
-            await console.log("PASS");
+            console.log("PASS");
         })();
     }
     expect_stdout: "PASS"
@@ -453,7 +964,7 @@ object_function: {
         }).f();
     }
     expect: {
-        (async function() {
+        (async () => {
             console.log("PASS");
         })();
     }
@@ -1235,10 +1746,10 @@ issue_4454_2: {
         f("PASS");
     }
     expect: {
-        function f(b) {
-            (async function(c = console.log(b)) {})();
-            var b = 42..toString();
-            console.log(b);
+        function f(a) {
+            (async function(c = console.log(a)) {})();
+            var a = 42..toString();
+            console.log(a);
         }
         f("PASS");
     }
@@ -1938,9 +2449,9 @@ issue_5032_normal: {
             console.log(value);
             return value;
         }
-        async function f(c) {
-            var b = log(c), c = b;
-            log(b);
+        async function f(a) {
+            var a = log(a), c = a;
+            log(a);
             log(c);
         }
         f("PASS");
@@ -2046,3 +2557,405 @@ issue_5070: {
     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"
+}
+
+issue_5250: {
+    options = {
+        inline: true,
+    }
+    input: {
+        (async function() {
+            await function() {
+                while (console.log("foo"));
+            }();
+            console.log("bar");
+        })();
+        console.log("baz");
+    }
+    expect: {
+        (async function() {
+            while (console.log("foo"));
+            await 0;
+            console.log("bar");
+        })();
+        console.log("baz");
+    }
+    expect_stdout: [
+        "foo",
+        "baz",
+        "bar",
+    ]
+    node_version: ">=8"
+}
+
+issue_5258_1: {
+    options = {
+        awaits: true,
+        inline: true,
+    }
+    input: {
+        (async function() {
+            (async function() {
+                throw "FAIL";
+            })();
+            return "PASS";
+        })().catch(console.log).then(console.log);
+    }
+    expect: {
+        (async function() {
+            (async function() {
+                throw "FAIL";
+            })();
+            return "PASS";
+        })().catch(console.log).then(console.log);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5258_2: {
+    options = {
+        awaits: true,
+        inline: true,
+    }
+    input: {
+        function f() {
+            throw "FAIL";
+        }
+        (async function() {
+            (async function() {
+                f();
+            })();
+            return "PASS";
+        })().catch(console.log).then(console.log);
+    }
+    expect: {
+        function f() {
+            throw "FAIL";
+        }
+        (async function() {
+            (async function() {
+                f();
+            })();
+            return "PASS";
+        })().catch(console.log).then(console.log);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5298: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        var a = "PASS";
+        (async function() {
+            for (a in [ 42 in null ]);
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        (async function() {
+            for (a in [ 42 in null ]);
+        })();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5305_1: {
+    options = {
+        inline: true,
+    }
+    input: {
+        var a = "PASS";
+        (async function() {
+            try {
+                return await function() {
+                    while (!console);
+                }();
+            } finally {
+                a = "FAIL";
+            }
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        (async function() {
+            try {
+                while (!console);
+                return await void 0;
+            } finally {
+                a = "FAIL";
+            }
+        })();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5305_2: {
+    options = {
+        inline: true,
+    }
+    input: {
+        var a = "PASS";
+        (async function() {
+            try {
+                throw null;
+            } catch (e) {
+                return await function() {
+                    while (!console);
+                }();
+            } finally {
+                a = "FAIL";
+            }
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        (async function() {
+            try {
+                throw null;
+            } catch (e) {
+                while (!console);
+                return await void 0;
+            } finally {
+                a = "FAIL";
+            }
+        })();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5305_3: {
+    options = {
+        awaits: true,
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        var a = "PASS";
+        (async function() {
+            try {
+                await function() {
+                    while (!console);
+                }();
+            } catch (e) {
+                a = "FAIL";
+            }
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        try {
+            while (!console);
+        } catch (e) {
+            a = "FAIL";
+        }
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    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

@@ -427,6 +427,44 @@ negated_if: {
     expect_stdout: "PASS"
 }
 
+concat_truthy: {
+    options = {
+        booleans: true,
+        evaluate: true,
+    }
+    input: {
+        console.log("foo") + (console.log("bar"), "baz") || console.log("moo");
+    }
+    expect: {
+        console.log("foo") + (console.log("bar"), "baz");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    expect_warnings: [
+        "WARN: + in boolean context always true [test/compress/booleans.js:1,8]",
+        "WARN: Condition left of || always true [test/compress/booleans.js:1,8]",
+    ]
+}
+
+process_returns: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        (function() {
+            return 42;
+        })() && console.log("PASS");
+    }
+    expect: {
+        (function() {
+            return 42;
+        })() && console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
 issue_3465_1: {
     options = {
         booleans: true,
@@ -697,3 +735,30 @@ issue_5041_2: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5228: {
+    options = {
+        booleans: true,
+        evaluate: true,
+        inline: true,
+        passes: 2,
+    }
+    input: {
+        console.log(function() {
+            return !function() {
+                do {
+                    return null;
+                } while (console);
+            }();
+        }());
+    }
+    expect: {
+        console.log(function() {
+            do {
+                return !0;
+            } while (console);
+            return !0;
+        }());
+    }
+    expect_stdout: "true"
+}

test/compress/classes.js

@@ -434,6 +434,33 @@ static_side_effects: {
         console.log(a);
     }
     expect: {
+        var a = "FAIL 1";
+        (class {
+            static c = a = "PASS";
+        });
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+static_side_effects_strict: {
+    options = {
+        inline: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        var a = "FAIL 1";
+        class A {
+            static p = a = "PASS";
+            q = a = "FAIL 2";
+        }
+        console.log(a);
+    }
+    expect: {
+        "use strict";
         var a = "FAIL 1";
         a = "PASS";
         console.log(a);
@@ -807,6 +834,33 @@ unused_await: {
         })();
     }
     expect: {
+        var await = "PASS";
+        (async function() {
+            (class {
+                static c = console.log(await);
+            });
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=12 <16"
+}
+
+unused_await_strict: {
+    options = {
+        inline: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        var await = "PASS";
+        (async function() {
+            class A {
+                static p = console.log(await);
+            }
+        })();
+    }
+    expect: {
+        "use strict";
         var await = "PASS";
         (async function() {
             (() => console.log(await))();
@@ -885,12 +939,14 @@ keep_fnames: {
         class Foo {}
         console.log(Foo.name, class Bar {}.name);
     }
+    expect_stdout: "Foo Bar"
+    node_version: ">=4"
 }
 
 issue_805_1: {
     options = {
         inline: true,
-        passes: 2,
+        passes: 3,
         pure_getters: "strict",
         reduce_vars: true,
         sequences: true,
@@ -926,7 +982,7 @@ issue_805_1: {
 issue_805_2: {
     options = {
         inline: true,
-        passes: 2,
+        passes: 3,
         pure_getters: "strict",
         reduce_vars: true,
         sequences: true,
@@ -1149,6 +1205,31 @@ issue_4705: {
         }
     }
     expect: {
+        (class {
+            [console.log("PASS")]() {}
+        });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_4705_strict: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        var a = "PASS";
+        class A {
+            p = a = "FAIL";
+            [console.log(a)];
+        }
+    }
+    expect: {
+        "use strict";
         console.log("PASS");
     }
     expect_stdout: "PASS"
@@ -1310,6 +1391,7 @@ issue_4725_1: {
 
 issue_4725_2: {
     options = {
+        if_return: true,
         inline: true,
     }
     input: {
@@ -1370,9 +1452,40 @@ issue_4756: {
     expect: {
         try {
             (class extends 42 {
-                [console.log("foo")]() {}
-            }),
-            (() => console.log("bar"))();
+                static [console.log("foo")] = console.log("bar");
+            });
+        } catch (e) {
+            console.log("baz");
+        }
+    }
+    expect_stdout: [
+        "foo",
+        "baz",
+    ]
+    node_version: ">=12"
+}
+
+issue_4756_strict: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        try {
+            class A extends 42 {
+                static [console.log("foo")] = console.log("bar");
+            }
+        } catch (e) {
+            console.log("baz");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            (class extends 42 {
+                static [console.log("foo")] = console.log("bar");
+            });
         } catch (e) {
             console.log("baz");
         }
@@ -1439,7 +1552,7 @@ issue_4829_1: {
     input: {
         "use strict";
         try {
-            class A extends { f(){} }.f {}
+            class A extends { f() {} }.f {}
         } catch (e) {
             console.log("PASS");
         }
@@ -1646,9 +1759,38 @@ issue_4962_1: {
     }
     expect: {
         (function g() {}),
-        void function() {
-            while (console.log(typeof g));
-        }();
+        void class {
+            static c = function() {
+                while (console.log(typeof g));
+            }();
+        };
+    }
+    expect_stdout: "undefined"
+    node_version: ">=12"
+}
+
+issue_4962_1_strict: {
+    options = {
+        ie: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        (function() {
+            function f() {
+                while (console.log(typeof g));
+            }
+            class A {
+                static p = f();
+            }
+        })(function g() {});
+    }
+    expect: {
+        "use strict";
+        (function g() {});
+        while (console.log(typeof g));
     }
     expect_stdout: "undefined"
     node_version: ">=12"
@@ -1672,6 +1814,36 @@ issue_4962_2: {
         }, typeof g));
     }
     expect: {
+        console.log(function f() {}(function g() {
+            (class {
+                static c = f;
+            });
+        }));
+    }
+    expect_stdout: "undefined"
+    node_version: ">=12"
+}
+
+issue_4962_2_strict: {
+    options = {
+        ie: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        console.log(function f() {}(function g() {
+            function h() {
+                f;
+            }
+            class A {
+                static p = h();
+            }
+        }, typeof g));
+    }
+    expect: {
+        "use strict";
         console.log(function f() {}(function g() {
             f;
         }));
@@ -1868,6 +2040,32 @@ issue_5015_3: {
         });
         console.log("PASS");
     }
+    expect: {
+        "use strict";
+        (class A {});
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5015_4: {
+    options = {
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        (class A {
+            static f() {
+                return A;
+            }
+        });
+        console.log("PASS");
+    }
     expect: {
         "use strict";
         console.log("PASS");
@@ -2027,6 +2225,40 @@ issue_5082_1: {
         })();
     }
     expect: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            (class {
+                static c = new A();
+            });
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5082_1_strict: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            class B {
+                static P = new A();
+            }
+        })();
+    }
+    expect: {
+        "use strict";
         (function() {
             class A {
                 p = console.log("PASS");
@@ -2058,6 +2290,41 @@ issue_5082_2: {
         })();
     }
     expect: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            (class {
+                static c = new A();
+            });
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5082_2_static: {
+    options = {
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            class B {
+                static P = new A();
+            }
+        })();
+    }
+    expect: {
+        "use strict";
         void new class {
             p = console.log("PASS");
             q() {}
@@ -2066,3 +2333,271 @@ issue_5082_2: {
     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"
+}
+
+issue_5294_1: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        (class A {
+            static p = console.log(typeof A);
+        });
+    }
+    expect: {
+        (class A {
+            static c = console.log(typeof A);
+        });
+    }
+    expect_stdout: "function"
+    node_version: ">=12"
+}
+
+issue_5294_2: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        class A {
+            static p = console.log(typeof A);
+        }
+    }
+    expect: {
+        class A {
+            static p = console.log(typeof A);
+        }
+    }
+    expect_stdout: "function"
+    node_version: ">=12"
+}
+
+issue_5294_3: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = this;
+        (class A {
+            static p = console.log(a === A ? "FAIL" : "PASS");
+        });
+    }
+    expect: {
+        var a = this;
+        (class A {
+            static p = console.log(a === A ? "FAIL" : "PASS");
+        });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5294_4: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        (class A {
+            static p = function() {
+                var a = this;
+                console.log(a === A ? "FAIL" : "PASS");
+            }();
+        });
+    }
+    expect: {
+        (class A {
+            static p = function() {
+                console.log(this === A ? "FAIL" : "PASS");
+            }();
+        });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5322: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 41;
+        class A {
+            static p() {
+                console.log(++a);
+            }
+            static q = this.p();
+        }
+    }
+    expect: {
+        var a = 41;
+        (class {
+            static p() {
+                console.log(++a);
+            }
+            static q = this.p();
+        });
+    }
+    expect_stdout: "42"
+    node_version: ">=12"
+}
+
+issue_5352: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a) {
+            var b;
+            new class {
+                [b = console.log(a)] = b;
+            }(a.p);
+        }
+        f("PASS");
+    }
+    expect: {
+        function f(a) {
+            var b;
+            new class {
+                [b = console.log(a)] = b;
+            }(a.p);
+        }
+        f("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5387: {
+    options = {
+        properties: true,
+    }
+    input: {
+        "use strict";
+        (function(a) {
+            try {
+                class A extends a {}
+            } catch (e) {
+                console.log("PASS");
+            }
+        })({
+            f() {
+                return this;
+            }
+        }.f);
+    }
+    expect: {
+        "use strict";
+        (function(a) {
+            try {
+                class A extends a {}
+            } catch (e) {
+                console.log("PASS");
+            }
+        })({
+            f() {
+                return this;
+            }
+        }.f);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5389: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        function log(m, n) {
+            console.log(m, n);
+        }
+        var a = log;
+        class A {
+            [a = "FAIL"] = a = "PASS";
+        }
+        var b = new A();
+        log(a, b.FAIL);
+    }
+    expect: {
+        function log(m, n) {
+            console.log(m, n);
+        }
+        var a = log;
+        class A {
+            [a = "FAIL"] = a = "PASS";
+        }
+        var b = new A();
+        log(a, b.FAIL);
+    }
+    expect_stdout: "PASS PASS"
+    node_version: ">=12"
+}
+
+issue_5436: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a) {
+            class A {
+                p = a;
+            }
+            var b = "FAIL";
+            A == b && b();
+            return new A();
+        }
+        console.log(f("PASS").p);
+    }
+    expect: {
+        function f(a) {
+            class A {
+                p = a;
+            }
+            var b = "FAIL";
+            A == b && b();
+            return new A();
+        }
+        console.log(f("PASS").p);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}

test/compress/collapse_vars.js

@@ -346,9 +346,7 @@ collapse_vars_if: {
             return "x" != "Bar" + x / 4 ? g9 : g5;
         }
         function f3(x) {
-            if (x)
-                return 1;
-            return 2;
+            return x ? 1 : 2;
         }
     }
 }
@@ -1912,6 +1910,42 @@ collapse_vars_regexp: {
     ]
 }
 
+collapse_arg_sequence: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            a("foo");
+        })((console.log("bar"), console.log));
+    }
+    expect: {
+        (function(a) {
+            (0, console.log)("foo");
+        })(console.log("bar"));
+    }
+    expect_stdout: [
+        "bar",
+        "foo",
+    ]
+}
+
+collapse_for_init: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        for (var a = (Math, console), b = a.log("PASS"); b;);
+    }
+    expect: {
+        Math;
+        for (var a, b = console.log("PASS"); b;);
+    }
+    expect_stdout: "PASS"
+}
+
 issue_1537: {
     options = {
         collapse_vars: true,
@@ -2545,7 +2579,7 @@ side_effects_property: {
     expect_stdout: true
 }
 
-undeclared: {
+undeclared_1: {
     options = {
         collapse_vars: true,
         unused: true,
@@ -2560,8 +2594,68 @@ undeclared: {
     }
     expect: {
         function f(x, y) {
+            return (b = y) + x;
+        }
+    }
+}
+
+undeclared_2: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        function f(x, y) {
+            var a;
+            a = x;
             b = y;
-            return b + x;
+            return a + b;
+        }
+    }
+    expect: {
+        function f(x, y) {
+            return x + (b = y);
+        }
+    }
+}
+
+undeclared_3: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        function f(x, y) {
+            var a;
+            a = x;
+            b = y;
+            return b + a();
+        }
+    }
+    expect: {
+        function f(x, y) {
+            return (b = y) + x();
+        }
+    }
+}
+
+undeclared_4: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        function f(x, y) {
+            var a;
+            a = x;
+            b = y;
+            return a() + b;
+        }
+    }
+    expect: {
+        function f(x, y) {
+            b = y;
+            return x() + b;
         }
     }
 }
@@ -2667,6 +2761,24 @@ chained_4: {
     expect_stdout: "foo undefined"
 }
 
+chained_5: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "PASS";
+        var a = (console, console.log(a));
+        a && ++a;
+    }
+    expect: {
+        var a = "PASS";
+        console;
+        var a;
+        (a = console.log(a)) && ++a;
+    }
+    expect_stdout: "PASS"
+}
+
 boolean_binary_1: {
     options = {
         collapse_vars: true,
@@ -2906,6 +3018,127 @@ compound_assignment_2: {
     expect_stdout: "4"
 }
 
+compound_assignment_3: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = 1;
+        a += (console.log("PASS"), 2);
+        a.p;
+    }
+    expect: {
+        var a = 1;
+        (a += (console.log("PASS"), 2)).p;
+    }
+    expect_stdout: "PASS"
+}
+
+compound_assignment_4: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+    }
+    input: {
+        A = "PASS";
+        var a = "";
+        a += (a = "FAIL", A);
+        a.p;
+        console.log(a);
+    }
+    expect: {
+        var a = "";
+        (a += (a = "FAIL", A = "PASS")).p;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}
+
+compound_assignment_5: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = 0, b;
+        a += 42;
+        b && (a *= null);
+        console.log(a);
+    }
+    expect: {
+        var a = 0, b;
+        a += 42;
+        b && (a *= null);
+        console.log(a);
+    }
+    expect_stdout: "42"
+}
+
+compound_assignment_6: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a;
+        a ^= 6;
+        a *= a + 1;
+        console.log(a);
+    }
+    expect: {
+        var a;
+        a = (a ^= 6) * (a + 1);
+        console.log(a);
+    }
+    expect_stdout: "42"
+}
+
+compound_assignment_7: {
+    options = {
+        assignments: true,
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "FA";
+        a = a + "I";
+        a = a + "L";
+        if (console)
+            a = "PASS";
+        console.log(a);
+    }
+    expect: {
+        var a = "FA";
+        a = a + "I" + "L";
+        if (console)
+            a = "PASS";
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}
+
+compound_assignment_8: {
+    options = {
+        assignments: true,
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 2;
+        a = 3 * a;
+        a = 7 * a;
+        console || (a = "FAIL");
+        console.log(a);
+    }
+    expect: {
+        var a = 2;
+        a = a * 3 * 7;
+        console || (a = "FAIL");
+        console.log(a);
+    }
+    expect_stdout: "42"
+}
+
 issue_2187_1: {
     options = {
         collapse_vars: true,
@@ -3030,10 +3263,10 @@ issue_2203_2: {
             a: "FAIL",
             b: function() {
                 return function(c) {
-                    return (String, (Object, function() {
+                    return (Object, function() {
                         return this;
-                    }())).a;
-                }();
+                    }()).a;
+                }(String);
             }
         }.b());
     }
@@ -3731,6 +3964,7 @@ issue_2437_1: {
     options = {
         collapse_vars: true,
         conditionals: true,
+        if_return: true,
         inline: true,
         join_vars: true,
         passes: 2,
@@ -3763,17 +3997,17 @@ issue_2437_1: {
         console.log(foo());
     }
     expect: {
-        console.log(function() {
-            if (xhrDesc) {
-                var result = !!(req = new XMLHttpRequest()).onreadystatechange;
-                return Object.defineProperty(XMLHttpRequest.prototype, "onreadystatechange", xhrDesc || {}),
-                    result;
-            }
-            var req = new XMLHttpRequest(), detectFunc = function(){};
-            return req.onreadystatechange = detectFunc,
-            result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc,
-            req.onreadystatechange = null, result;
-        }());
+        var req, detectFunc, result;
+        console.log((
+            xhrDesc ? (result = !!(req = new XMLHttpRequest).onreadystatechange,
+                Object.defineProperty(XMLHttpRequest.prototype, "onreadystatechange", xhrDesc||{})
+            ) : (
+                (req = new XMLHttpRequest).onreadystatechange = detectFunc = function(){},
+                result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc,
+                req.onreadystatechange = null
+            ),
+            result
+        ));
     }
 }
 
@@ -3783,6 +4017,7 @@ issue_2437_2: {
         conditionals: true,
         inline: true,
         join_vars: true,
+        negate_iife: true,
         passes: 3,
         reduce_funcs: true,
         reduce_vars: true,
@@ -3813,15 +4048,15 @@ issue_2437_2: {
         foo();
     }
     expect: {
-        !function() {
-            if (xhrDesc)
-                return (req = new XMLHttpRequest()).onreadystatechange,
-                    Object.defineProperty(XMLHttpRequest.prototype, "onreadystatechange", xhrDesc || {});
-            var req = new XMLHttpRequest();
-            req.onreadystatechange = function(){},
+        var req;
+        xhrDesc ? (
+            (req = new XMLHttpRequest).onreadystatechange,
+            Object.defineProperty(XMLHttpRequest.prototype, "onreadystatechange", xhrDesc || {})
+        ) : (
+            (req = new XMLHttpRequest).onreadystatechange = function(){},
             req[SYMBOL_FAKE_ONREADYSTATECHANGE_1],
-            req.onreadystatechange = null;
-        }();
+            req.onreadystatechange = null
+        );
     }
 }
 
@@ -6443,7 +6678,8 @@ assign_undeclared: {
         console.log(typeof B);
     }
     expect: {
-        B = new (console.log(42), function() {})();
+        console.log(42);
+        B = new function() {}();
         console.log(typeof B);
     }
     expect_stdout: [
@@ -8156,9 +8392,9 @@ issue_3884_1: {
         console.log(a, b);
     }
     expect: {
-        var a = 100, b = 1;
-        b <<= ++a;
-        console.log(a, b);
+        var a = 100;
+        ++a;
+        console.log(a, 32);
     }
     expect_stdout: "101 32"
 }
@@ -8778,6 +9014,27 @@ collapse_and_assign: {
     expect_stdout: "PASS"
 }
 
+collapse_and_assign_property: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function f() {
+            f && (f.p = "PASS");
+            return f.p;
+        }());
+    }
+    expect: {
+        console.log(function f() {
+            return f.p = f ? "PASS" : f.p;
+        }());
+    }
+    expect_stdout: "PASS"
+}
+
 collapse_or_assign: {
     options = {
         collapse_vars: true,
@@ -8795,7 +9052,7 @@ collapse_or_assign: {
         var a = {
             p: "PASS",
         };
-        log(a = !a.q ? a.p : a);
+        log(a = a.q ? a: a.p);
     }
     expect_stdout: "PASS"
 }
@@ -9139,9 +9396,7 @@ issue_4908: {
         console.log(d[1]);
     }
     expect: {
-        var a = 0, b;
-        console || a++;
-        var c = a, d = [ (d = a) && d, d += 42 ];
+        var a = 0, b, c = (console || a++, a), d = [ (d = a) && d, d += 42 ];
         console.log(d[1]);
     }
     expect_stdout: "42"
@@ -9253,13 +9508,13 @@ issue_4920_2: {
         console.log(b);
     }
     expect: {
-        var o = {
+        var o;
+        var a = "PASS", b;
+        ({
             get PASS() {
                 a = "FAIL";
             },
-        };
-        var a = "PASS", b;
-        o[b = a];
+        })[b = a];
         console.log(b);
     }
     expect_stdout: "PASS"
@@ -9283,16 +9538,47 @@ issue_4920_3: {
     }
     expect: {
         var log = console.log;
-        var o = {
+        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: {
@@ -9343,9 +9629,8 @@ inline_throw: {
     expect: {
         try {
             (function(a) {
-                return function() {
-                    throw a;
-                }();
+                throw a;
+                return;
             })("PASS");
         } catch (e) {
             console.log(e);
@@ -9482,3 +9767,215 @@ issue_5112_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"
+}
+
+issue_5273: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        inline: true,
+        reduce_vars: true,
+        sequences: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "10", b = 1;
+        function f(c, d) {
+            return d;
+        }
+        f((b += a, b *= a), f);
+        console.log(b);
+    }
+    expect: {
+        var a = "10", b = 1;
+        function f(c, d) {
+            return d;
+        }
+        b = 1100,
+        f,
+        console.log(b);
+    }
+    expect_stdout: "1100"
+}
+
+issue_5276: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = A = "PASS";
+        a.p += null;
+        a.p -= 42;
+        console.log(a);
+    }
+    expect: {
+        var a = A = "PASS";
+        a.p = a.p + null - 42;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5277: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            var a = function() {
+                a += null;
+                a -= 42;
+            };
+        }());
+    }
+    expect: {
+        console.log(function() {}());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_5309_1: {
+    options = {
+        collapse_vars: true,
+        conditionals: true,
+        toplevel: true,
+    }
+    input: {
+        if (console)
+            var a = (console.log("PASS"), b), b = a;
+        else
+            console.log("FAIL");
+    }
+    expect: {
+        var a, b;
+        console ? (console.log("PASS"), b = b) : console.log("FAIL");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5309_2: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b;
+        console ? (a = (console.log("PASS"), b), b = a) : console.log("FAIL");
+    }
+    expect: {
+        var a, b;
+        console ? (console.log("PASS"), b = b) : console.log("FAIL");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5394: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+    }
+    input: {
+        try {
+            throw A.p = (console.log("FAIL"), []), !1;
+        } catch (e) {
+            console.log(typeof e);
+        }
+    }
+    expect: {
+        try {
+            throw !(A.p = (console.log("FAIL"), []));
+        } catch (e) {
+            console.log(typeof e);
+        }
+    }
+    expect_stdout: "object"
+}
+
+issue_5396: {
+    options = {
+        collapse_vars: true,
+        merge_vars: true,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a, b;
+        function f() {}
+        b = 0;
+        new function g(c) {
+            var d = a && g(e), e = ++d, i = [ 42 ];
+            for (var j in i)
+                console.log("PASS"),
+                i;
+        }();
+    }
+    expect: {
+        var a, b;
+        function f() {}
+        b = 0;
+        (function g(c) {
+            a && g();
+            for (var j in [ 42 ])
+                console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}

test/compress/comparisons.js

@@ -489,7 +489,36 @@ issue_3413: {
     }
     expect: {
         var b;
-        void 0 !== ("" < b || void 0) || console.log("PASS");
+        void 0 === ("" < b || void 0) && console.log("PASS");
     }
     expect_stdout: "PASS"
 }
+
+nullish_assign: {
+    options = {
+        comparisons: true,
+    }
+    input: {
+        var a;
+        void 0 !== (a = "PASS".split("")) && null !== a && console.log(a.join("-"));
+    }
+    expect: {
+        var a;
+        null != (a = "PASS".split("")) && console.log(a.join("-"));
+    }
+    expect_stdout: "P-A-S-S"
+}
+
+nullish_chain: {
+    options = {
+        comparisons: true,
+    }
+    input: {
+        var a;
+        A || B || void 0 === a || null === a || C;
+    }
+    expect: {
+        var a;
+        A || B || null == a || C;
+    }
+}

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

@@ -82,14 +82,14 @@ ifs_3_should_warn: {
         "WARN: Boolean && always false [test/compress/conditionals.js:3,12]",
         "WARN: Condition left of && always false [test/compress/conditionals.js:3,12]",
         "WARN: Condition always false [test/compress/conditionals.js:3,12]",
+        "WARN: Dropping side-effect-free statement [test/compress/conditionals.js:3,12]",
         "WARN: Dropping unreachable code [test/compress/conditionals.js:3,34]",
         "WARN: + in boolean context always true [test/compress/conditionals.js:10,19]",
         "WARN: Boolean || always true [test/compress/conditionals.js:10,12]",
         "WARN: Condition left of || always true [test/compress/conditionals.js:10,12]",
         "WARN: Condition always true [test/compress/conditionals.js:10,12]",
-        "WARN: Dropping unreachable code [test/compress/conditionals.js:12,15]",
-        "WARN: Dropping side-effect-free statement [test/compress/conditionals.js:3,12]",
         "WARN: Dropping side-effect-free statement [test/compress/conditionals.js:10,12]",
+        "WARN: Dropping unreachable code [test/compress/conditionals.js:12,15]",
     ]
 }
 
@@ -1924,3 +1924,141 @@ object_super: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_5232_1: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        (function() {
+            if (Math) {
+                function f() {}
+                for (var a in [ 42 ])
+                    console.log(typeof f);
+            } else {
+                var b = null;
+                return true;
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            var b;
+            if (!Math)
+                return b = null, true;
+            function f() {}
+            for (var a in [ 42 ]) console.log(typeof f);
+        })();
+    }
+    expect_stdout: "function"
+}
+
+issue_5232_2: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        console.log(function() {
+            if (!Math);
+            else {
+                var b = null;
+                return "PASS";
+            }
+        }());
+    }
+    expect: {
+        console.log(function() {
+            var b;
+            if (Math)
+                return b = null, "PASS";
+        }());
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5232_3: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        console.log(function() {
+            return function() {
+                if (console)
+                    console.log("PASS");
+                else {
+                    var a = null;
+                    return "FAIL";
+                }
+            };
+        }()());
+    }
+    expect: {
+        console.log(function() {
+            return function() {
+                var a;
+                if (!console)
+                    return a = null, "FAIL";
+                console.log("PASS");
+            };
+        }()());
+    }
+    expect_stdout: [
+        "PASS",
+        "undefined",
+    ]
+}
+
+issue_5334_1: {
+    options = {
+        conditionals: true,
+        hoist_props: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            if (console.log("PASS"))
+                var o = true, o = {
+                    p: o += console.log("FAIL"),
+                };
+        }
+        f();
+    }
+    expect: {
+        (function() {
+            var o;
+            console.log("PASS") && (o = true, o = {
+                p: o += console.log("FAIL"),
+            });
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5334_2: {
+    options = {
+        conditionals: true,
+        hoist_props: true,
+        inline: true,
+        passes: 3,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            if (console.log("PASS"))
+                var o = true, o = {
+                    p: o += console.log("FAIL"),
+                };
+        }
+        f();
+    }
+    expect: {
+        console.log("PASS") && console.log("FAIL");
+    }
+    expect_stdout: "PASS"
+}

test/compress/const.js

@@ -220,6 +220,32 @@ merge_vars_3: {
     expect_stdout: true
 }
 
+merge_vars_4: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 1;
+        console.log(typeof a);
+        {
+            var b = console;
+            console.log(typeof b);
+            const a = 0;
+        }
+    }
+    expect: {
+        var a = 1;
+        console.log(typeof a);
+        {
+            var b = console;
+            console.log(typeof b);
+            const a = 0;
+        }
+    }
+    expect_stdout: true
+}
+
 use_before_init_1: {
     options = {
         reduce_vars: true,
@@ -571,8 +597,7 @@ do_if_continue_1: {
     }
     expect: {
         do {
-            if (!console);
-            else {
+            if (console) {
                 console.log("PASS");
                 {
                     const a = 0;
@@ -602,8 +627,7 @@ do_if_continue_2: {
     }
     expect: {
         do {
-            if (!console);
-            else {
+            if (console) {
                 console.log("PASS");
                 {
                     const a = 0;
@@ -838,12 +862,10 @@ issue_4202: {
     expect: {
         {
             const o = {};
-            (function() {
-                function f() {
-                    o.p = 42;
-                }
-                f(f);
-            })();
+            function f() {
+                o.p = 42;
+            }
+            f(f);
             console.log(o.p++);
         }
     }
@@ -1219,9 +1241,9 @@ issue_4248: {
     expect_stdout: "PASS"
 }
 
-issue_4261: {
+issue_4261_1: {
     options = {
-        inline: true,
+        inline: 3,
         reduce_funcs: true,
         reduce_vars: true,
         toplevel: true,
@@ -1259,6 +1281,43 @@ issue_4261: {
     expect_stdout: "42"
 }
 
+issue_4261_2: {
+    options = {
+        if_return: true,
+        inline: true,
+        reduce_funcs: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        {
+            const a = 42;
+            (function() {
+                function f() {
+                    console.log(a);
+                }
+                function g() {
+                    while (f());
+                }
+                (function() {
+                    while (g());
+                })();
+            })();
+        }
+    }
+    expect: {
+        {
+            const a = 42;
+            function g() {
+                while (void console.log(a));
+            }
+            while (g());
+        }
+    }
+    expect_stdout: "42"
+}
+
 issue_4274_1: {
     options = {
         loops: true,
@@ -1457,6 +1516,7 @@ issue_4689: {
 
 issue_4691: {
     options = {
+        conditionals: true,
         if_return: true,
         toplevel: true,
     }
@@ -1692,3 +1752,106 @@ issue_4965_2: {
     expect_stdout: "undefined"
     node_version: ">=4"
 }
+
+issue_5254: {
+    options = {
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        do {
+            (function() {
+                const a = console.log;
+                a && a("foo");
+            })();
+        } while (console.log("bar"));
+    }
+    expect: {
+        do {
+            const a = console.log;
+            a && a("foo");
+        } while (console.log("bar"));
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_5260: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        "use strict";
+        var a = "foo", o;
+        while (console.log("bar"));
+        o = {
+            baz: function(b) {
+                console.log(a, b);
+            },
+        };
+        for (const a in o)
+            o[a](a);
+    }
+    expect: {
+        "use strict";
+        var a = "foo", o;
+        while (console.log("bar"));
+        o = {
+            baz: function(b) {
+                console.log(a, b);
+            },
+        };
+        for (const a in o)
+            o[a](a);
+    }
+    expect_stdout: [
+        "bar",
+        "foo baz",
+    ]
+    node_version: ">=4"
+}
+
+issue_5319: {
+    options = {
+        collapse_vars: true,
+        merge_vars: true,
+    }
+    input: {
+        (function(a, c) {
+            var b = a, c = b;
+            {
+                const a = c;
+                console.log(c());
+            }
+        })(function() {
+            return "PASS";
+        });
+    }
+    expect: {
+        (function(a, c) {
+            var b = a, c;
+            {
+                const a = c = b;
+                console.log(c());
+            }
+        })(function() {
+            return "PASS";
+        });
+    }
+    expect_stdout: true
+}
+
+issue_5338: {
+    options = {
+        unused: true,
+    }
+    input: {
+        const a = a;
+    }
+    expect: {
+        const a = a;
+    }
+    expect_stdout: true
+}

test/compress/default-values.js

@@ -158,6 +158,28 @@ process_boolean_returns: {
     node_version: ">=6"
 }
 
+collapse_arg_sequence: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(a = (console.log("bar"), console.log)) {
+            a("foo");
+        })();
+    }
+    expect: {
+        (function(a = console.log("bar")) {
+            (0, console.log)("foo");
+        })();
+    }
+    expect_stdout: [
+        "bar",
+        "foo",
+    ]
+    node_version: ">=6"
+}
+
 collapse_value_1: {
     options = {
         collapse_vars: true,
@@ -1037,7 +1059,7 @@ mangle_arrow_1: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.3"
 }
 
 mangle_arrow_1_toplevel: {
@@ -1073,7 +1095,7 @@ mangle_arrow_1_toplevel: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.3"
 }
 
 mangle_arrow_2: {
@@ -1109,7 +1131,7 @@ mangle_arrow_2: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.3"
 }
 
 mangle_arrow_2_toplevel: {
@@ -1145,7 +1167,7 @@ mangle_arrow_2_toplevel: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=6"
+    node_version: ">=6.9.3"
 }
 
 issue_4444: {
@@ -1587,7 +1609,7 @@ issue_4510_2: {
         };
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4523: {
@@ -1866,7 +1888,7 @@ issue_5057_2: {
 
 issue_5057_3: {
     options = {
-        inline: true,
+        inline: 3,
         unused: true,
     }
     input: {
@@ -1889,6 +1911,31 @@ issue_5057_3: {
     node_version: ">=6"
 }
 
+issue_5057_4: {
+    options = {
+        if_return: true,
+        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) {
+            var b = "FAIL 2";
+            (function(a = console.log("FAIL 1")) {})(b);
+            console.log(a);
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 issue_5065: {
     options = {
         pure_getters: "strict",
@@ -1904,3 +1951,291 @@ issue_5065: {
     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"
+}
+
+issue_5246_1: {
+    options = {
+        keep_fargs: false,
+        pure_getters: true,
+        unused: true,
+    }
+    input: {
+        console.log(function({} = 42) {
+            return "PASS";
+        }("foo"));
+    }
+    expect: {
+        console.log(function() {
+            return "PASS";
+        }());
+    }
+    expect_stdout: "PASS"
+    expect_warnings: [
+        "INFO: Dropping unused default argument {}=42 [test/compress/default-values.js:1,29]",
+    ]
+    node_version: ">=6"
+}
+
+issue_5246_2: {
+    options = {
+        keep_fargs: false,
+        unused: true,
+    }
+    input: {
+        (function f(a = "FAIL", [] = 42) {
+            console.log(a);
+        })("PASS", []);
+    }
+    expect: {
+        (function(a = "FAIL") {
+            console.log(a);
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5246_3: {
+    options = {
+        default_values: true,
+        keep_fargs: false,
+        unused: true,
+    }
+    input: {
+        console.log(function f([ , {} ] = null){}([ , {} ]));
+    }
+    expect: {
+        console.log(function([ {} ]){}([ {} ]));
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+issue_5256: {
+    options = {
+        inline: true,
+    }
+    input: {
+        (function(arguments = console.log) {
+            console;
+        })();
+        console.log(typeof arguments);
+    }
+    expect: {
+        // Syntax error on Node.js v6
+        (function(arguments = console.log) {
+            console;
+        })();
+        console.log(typeof arguments);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=8"
+}
+
+issue_5314_1: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        A = this;
+        new function() {
+            (function(a = console.log(this === A ? "PASS" : "FAIL")) {})();
+        }();
+    }
+    expect: {
+        A = this;
+        (function() {
+            (function(a = console.log(this === A ? "PASS" : "FAIL")) {})();
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5314_2: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        A = this;
+        new function() {
+            ((a = console.log(this === A ? "FAIL" : "PASS")) => {})();
+        }();
+    }
+    expect: {
+        A = this;
+        new function() {
+            console.log(this === A ? "FAIL" : "PASS");
+        }();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5336: {
+    options = {
+        default_values: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        do {
+            (function f(b = console.log("PASS")) {
+                a = f;
+            })(42);
+        } while (a());
+    }
+    expect: {
+        var a;
+        do {
+            (function f(b = console.log("PASS")) {
+                a = f;
+            })(42);
+        } while (a());
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5340_1: {
+    options = {
+        keep_fargs: true,
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        var a;
+        (function(b = 42) {})(({ p: a } = true).q);
+        console.log(a);
+    }
+    expect: {
+        var a;
+        (function(b = 0) {})(({ p: a } = true).q);
+        console.log(a);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+issue_5340_2: {
+    options = {
+        keep_fargs: true,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        (function(b = 42) {})(({ p: a } = true).q);
+        console.log(a);
+    }
+    expect: {
+        var a;
+        [ [].e = 0 ] = [ ({ p: a } = true).q ];
+        console.log(a);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+issue_5340_3: {
+    options = {
+        keep_fargs: false,
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        var a;
+        (function(b = 42) {})(({ p: a } = true).q);
+        console.log(a);
+    }
+    expect: {
+        var a;
+        (function() {})(a = true["p"]);
+        console.log(a);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+issue_5407: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        (function(a) {
+            for (var i = 0; i < 2; i++)
+                (function(b = 4) {
+                    console.log(b);
+                    a = 2;
+                })(a);
+        })();
+    }
+    expect: {
+        (function(a) {
+            for (var i = 0; i < 2; i++)
+                (function(b = 4) {
+                    console.log(b);
+                    a = 2;
+                })(a);
+        })();
+    }
+    expect_stdout: [
+        "4",
+        "2",
+    ]
+    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: {
@@ -395,7 +395,8 @@ funarg_unused_6_keep_fargs: {
     }
     expect: {
         (function() {
-            var {} = (console, 42);
+            console;
+            var {} = 42;
         })();
         console.log(typeof a);
     }
@@ -691,7 +692,7 @@ funarg_inline: {
     node_version: ">=6"
 }
 
-process_boolean_returns: {
+process_returns: {
     options = {
         booleans: true,
     }
@@ -705,9 +706,7 @@ process_boolean_returns: {
     expect: {
         console.log(function({ length }) {
             return length ? "FAIL" : "PASS";
-        }(function() {
-            return 42;
-        }));
+        }(function() {}));
     }
     expect_stdout: "PASS"
     node_version: ">=6"
@@ -1129,7 +1128,7 @@ drop_unused_2: {
         }
         f();
     }
-    expect:{
+    expect: {
         (function(a) {
             console.log("PASS");
         })();
@@ -1581,6 +1580,75 @@ 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,
@@ -1775,13 +1843,13 @@ issue_4294: {
     expect: {
         A = "PASS";
         (function() {
-            var b = function({
-                [b]: {},
+            var a = function({
+                [a]: {},
             }) {}({
-                [b]: 0,
+                [a]: 0,
             });
-            var b = A;
-            console.log(b);
+            var a = A;
+            console.log(a);
         })();
     }
     expect_stdout: "PASS"
@@ -2000,7 +2068,7 @@ issue_4319: {
 
 issue_4321: {
     options = {
-        inline: true,
+        inline: 3,
         keep_fargs: false,
     }
     input: {
@@ -2127,7 +2195,7 @@ issue_4372_2: {
     }
     expect: {
         var a;
-        [ a ] = [ "PASS", "FAIL" ];
+        [ a ] = a = [ "PASS", "FAIL" ];
         console.log(a);
     }
     expect_stdout: "PASS"
@@ -3125,3 +3193,376 @@ issue_5114_3: {
     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"
+}
+
+issue_5222: {
+    options = {
+        hoist_props: true,
+        inline: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            do {
+                (function() {
+                    var a = {
+                        p: [ a ] = [],
+                    };
+                })();
+            } while (console.log("PASS"));
+        }
+        f();
+    }
+    expect: {
+        do {
+            a = void 0,
+            a = {
+                p: [ a ] = [],
+            };
+        } while (console.log("PASS"));
+        var a;
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5288: {
+    options = {
+        conditionals: true,
+        inline: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        while (function([]) {}([ function f() {
+            if (console)
+                return console.log("PASS");
+            else {
+                let a = 0;
+            }
+        }() ]));
+    }
+    expect: {
+        while (console ? console.log("PASS") : 0, void 0);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5314_1: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        A = this;
+        new function() {
+            (function({
+                [console.log(this === A ? "PASS" : "FAIL")]: a,
+            }) {})(42);
+        }();
+    }
+    expect: {
+        A = this;
+        (function() {
+            (function({
+                [console.log(this === A ? "PASS" : "FAIL")]: a,
+            }) {})(42);
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5314_2: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        A = this;
+        new function() {
+            (({
+                [console.log(this === A ? "FAIL" : "PASS")]: a,
+            }) => {})(42);
+        }();
+    }
+    expect: {
+        A = this;
+        new function() {
+            [ {
+                [console.log(this === A ? "FAIL" : "PASS")]: [].e,
+            } ] = [ 42 ];
+        }();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5370: {
+    options = {
+        dead_code: true,
+        ie: true,
+        unused: true,
+    }
+    input: {
+        console.log(function arguments({}) {
+            return arguments;
+            try {} catch (e) {
+                var arguments;
+            }
+        }(42));
+    }
+    expect: {
+        console.log(function arguments({}) {
+            return arguments;
+            var arguments;
+        }(42));
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+issue_5405_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+    }
+    input: {
+        var [ a ] = [ {} ];
+        console.log(a === a ? "PASS" : "FAIL");
+    }
+    expect: {
+        var [ a ] = [ {} ];
+        console.log(true ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5405_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+    }
+    input: {
+        var { p: a } = { p: [] };
+        console.log(a === a ? "PASS" : "FAIL");
+    }
+    expect: {
+        var { p: a } = { p: [] };
+        console.log(true ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5423: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b;
+        function f({
+            [function() {
+                if (++a)
+                    return 42;
+            }()]: c
+        }) {}
+        f(b = f);
+        console.log(typeof b);
+    }
+    expect: {
+        var a, b;
+        function f({
+            [function() {
+                if (++a)
+                    return 42;
+            }()]: c
+        }) {}
+        f(b = f);
+        console.log(typeof b);
+    }
+    expect_stdout: "function"
+    node_version: ">=6"
+}

test/compress/directives.js

@@ -129,3 +129,32 @@ valid_after_invalid_2: {
     }
     expect_stdout: "undefined"
 }
+
+issue_5368_1: {
+    options = {
+        directives: true,
+        expression: true,
+    }
+    input: {
+        "foo";
+    }
+    expect: {
+        "foo";
+    }
+}
+
+issue_5368_2: {
+    options = {
+        directives: true,
+        expression: true,
+    }
+    input: {
+        "foo";
+        (function() {
+            "bar";
+        })();
+    }
+    expect: {
+        (function() {})();
+    }
+}

test/compress/drop-unused.js

@@ -1233,8 +1233,11 @@ issue_2105_2: {
 issue_2105_3: {
     options = {
         inline: true,
-        passes: 2,
+        join_vars: true,
+        passes: 3,
         reduce_vars: true,
+        side_effects: true,
+        sequences: true,
         unused: true,
     }
     input: {
@@ -1258,12 +1261,12 @@ issue_2105_3: {
         });
     }
     expect: {
-        !void void {
+        ({
             prop: function() {
-                console.log;
-                void console.log("PASS");
-            }
-        }.prop();
+                console.log,
+                console.log("PASS");
+            },
+        }).prop();
     }
     expect_stdout: "PASS"
 }
@@ -1728,7 +1731,8 @@ issue_2768: {
     }
     expect: {
         var a = "FAIL";
-        var c = (d = a, void (d && (a = "PASS")));
+        d = a;
+        var c = void (d && (a = "PASS"));
         var d;
         console.log(a, typeof c);
     }
@@ -1765,7 +1769,7 @@ issue_2846: {
 issue_805_1: {
     options = {
         inline: true,
-        passes: 2,
+        passes: 3,
         pure_getters: "strict",
         reduce_vars: true,
         sequences: true,
@@ -1798,7 +1802,7 @@ issue_805_1: {
 issue_805_2: {
     options = {
         inline: true,
-        passes: 2,
+        passes: 3,
         pure_getters: "strict",
         reduce_vars: true,
         sequences: true,
@@ -2382,7 +2386,8 @@ issue_3664: {
     }
     expect: {
         console.log(function() {
-            var a, b = (a = (a = [ b && console.log("FAIL") ]).p = 0, 0);
+            a = (a = [ b && console.log("FAIL") ]).p = 0;
+            var a, b = 0;
             return "PASS";
         }());
     }
@@ -2551,10 +2556,9 @@ issue_3899: {
         console.log(typeof a);
     }
     expect: {
-        function a() {
+        console.log(typeof function() {
             return 2;
-        }
-        console.log(typeof a);
+        });
     }
     expect_stdout: "function"
 }
@@ -2652,7 +2656,7 @@ issue_3956: {
         collapse_vars: true,
         evaluate: true,
         inline: true,
-        passes: 2,
+        passes: 3,
         reduce_vars: true,
         sequences: true,
         side_effects: true,
@@ -2783,7 +2787,7 @@ issue_3986: {
     expect_stdout: "0"
 }
 
-issue_4017: {
+issue_4017_1: {
     options = {
         pure_getters: "strict",
         reduce_vars: true,
@@ -2801,7 +2805,31 @@ issue_4017: {
         var a = 0;
         console.log(function() {
             c &= 0;
-            var c;
+            var c = a++ + (A = a);
+        }());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4017_2: {
+    options = {
+        passes: 2,
+        pure_getters: "strict",
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var a = 0;
+        console.log(function f() {
+            var b = c &= 0;
+            var c = a++ + (A = a);
+            var d = c && c[f];
+        }());
+    }
+    expect: {
+        var a = 0;
+        console.log(function() {
+            0;
             a++,
             A = a;
         }());
@@ -2916,7 +2944,7 @@ issue_4133: {
         console.log(a);
     }
     expect: {
-        var b = 1;
+        var a = 1;
         console.log(0);
     }
     expect_stdout: "0"
@@ -3062,7 +3090,7 @@ issue_4184: {
     expect_stdout: "42"
 }
 
-issue_4235: {
+issue_4235_1: {
     options = {
         inline: true,
         reduce_vars: true,
@@ -3081,13 +3109,37 @@ issue_4235: {
     }
     expect: {
         void function() {
-            var f;
-            console.log(f);
+            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() {
+            {
+                const f = 0;
+            }
+            (function f() {
+                var f = console.log(f);
+            })();
+        })();
+    }
+    expect: {
+        console.log(void 0);
+    }
+    expect_stdout: "undefined"
+}
+
 issue_4404: {
     options = {
         pure_getters: "strict",
@@ -3220,7 +3272,7 @@ issue_4558_1: {
     expect: {
         var a = 0;
         var b = c >>>= a;
-        var c;
+        var c = 0;
         b && a++,
         console.log(a);
     }
@@ -3306,6 +3358,7 @@ issue_4806_1: {
 issue_4806_2: {
     options = {
         sequences: true,
+        side_effects: true,
         toplevel: true,
         unused: true,
     }
@@ -3492,3 +3545,73 @@ issue_5079: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5224: {
+    options = {
+        evaluate: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            try {
+                var b = function() {
+                    var a = "FAIL 1";
+                    null && a;
+                    a = console.log(a);
+                }(new function(c, d) {
+                    console.log(d);
+                    a;
+                }("FAIL 2", Infinity));
+            } finally {
+                return f;
+            }
+        }
+        f();
+    }
+    expect: {
+        (function f() {
+            try {
+                (function() {
+                    var a = "FAIL 1";
+                    null;
+                    a = console.log(a);
+                })(function() {
+                    console.log(1 / 0);
+                    a;
+                }());
+            } finally {
+                return f;
+            }
+        })();
+    }
+    expect_stdout: "Infinity"
+}
+
+issue_5271: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            do {
+                var a = b = 0 ^ f, b = b;
+            } while (console.log(42 - b));
+        }
+        f();
+    }
+    expect: {
+        (function f() {
+            do {
+                var b;
+                b = 0 ^ f;
+            } while (console.log(42 - b));
+        })();
+    }
+    expect_stdout: "42"
+}

test/compress/evaluate.js

@@ -745,7 +745,7 @@ call_args: {
     expect: {
         var a = 1;
         console.log(1);
-        +(1, 1);
+        1, 1;
     }
     expect_stdout: true
 }
@@ -769,7 +769,7 @@ call_args_drop_param: {
     }
     expect: {
         console.log(1);
-        +(b, 1);
+        b, 1;
     }
     expect_stdout: true
 }
@@ -888,6 +888,25 @@ unsafe_charAt_noop: {
     expect_stdout: "f  n"
 }
 
+chained_side_effects: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log("foo") || (console.log("bar"), "baz") || console.log("moo");
+    }
+    expect: {
+        console.log("foo") || (console.log("bar"), "baz");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    expect_warnings: [
+        "WARN: Condition left of || always true [test/compress/evaluate.js:1,8]",
+    ]
+}
+
 issue_1649: {
     options = {
         evaluate: true,
@@ -2752,8 +2771,7 @@ issue_3944: {
     }
     expect: {
         void function f() {
-            while (a = 0 == (a = void 0), console.log(a), void 0);
-            var a;
+            while (0 == void 0, console.log(false), void 0);
             f;
         }();
     }
@@ -3203,7 +3221,7 @@ issue_4552: {
     expect_stdout: "NaN"
 }
 
-issue_4886: {
+issue_4886_1: {
     options = {
         evaluate: true,
         unsafe: true,
@@ -3222,3 +3240,139 @@ 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"
+}
+
+issue_5354: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        function f(a) {
+            return +a.toExponential(1);
+        }
+        function g(b) {
+            return 0 + b.toFixed(2);
+        }
+        function h(c) {
+            return 1 * c.toPrecision(3);
+        }
+        console.log(typeof f(45), typeof g(67), typeof h(89));
+    }
+    expect: {
+        function f(a) {
+            return +a.toExponential(1);
+        }
+        function g(b) {
+            return 0 + b.toFixed(2);
+        }
+        function h(c) {
+            return +c.toPrecision(3);
+        }
+        console.log(typeof f(45), typeof g(67), typeof h(89));
+    }
+    expect_stdout: "number string number"
+}
+
+issue_5356: {
+    options = {
+        evaluate: true,
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            return a++;
+            var a = a;
+        }());
+    }
+    expect: {
+        console.log(+a);
+        var a;
+    }
+    expect_stdout: "NaN"
+}
+
+issue_5362_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = -console;
+        console.log(delete +a);
+    }
+    expect: {
+        var a = -console;
+        console.log((+a, true));
+    }
+    expect_stdout: "true"
+}
+
+issue_5362_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var a = -console;
+        console.log(delete +a);
+    }
+    expect: {
+        console.log(true);
+    }
+    expect_stdout: "true"
+}
+
+issue_5380: {
+    options = {
+        evaluate: true,
+        keep_fnames: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f(b) {
+            return function g() {
+                for (b in { PASS: 42 });
+            }(), b;
+        }("FAIL");
+        console.log(a);
+    }
+    expect: {
+        var a = function f(b) {
+            return function g() {
+                for (b in { PASS: 42 });
+            }(), b;
+        }("FAIL");
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}

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, a, typeof this);
-            }((A = 0, 2 ** 30));
+                console.log(typeof f, 2 ** 30, typeof this);
+            }(A = 0);
         })();
     }
     expect_stdout: "function 1073741824 object"

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));
@@ -931,7 +934,7 @@ issue_3411: {
     expect: {
         var c = 1;
         !function f() {
-            var o_p = --c && f();
+            var o, o_p = --c && f();
             +{} || console.log("PASS");
         }();
     }
@@ -1042,9 +1045,7 @@ issue_3945_1: {
     expect: {
         function f() {
             o.p;
-            var o = {
-                q: 0,
-            };
+            var o, o_q = 0;
         }
     }
 }
@@ -1063,9 +1064,7 @@ issue_3945_2: {
     }
     expect: {
         console.log(typeof o);
-        var o = {
-            p: 0,
-        };
+        var o, o_p = 0;
     }
     expect_stdout: "undefined"
 }
@@ -1134,10 +1133,46 @@ issue_4985: {
         }());
     }
     expect: {
-        var a_p = 42;
+        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 = console;
+        log = o.log;
+        o = function(a) {
+            console.log(a ? "PASS" : "FAIL");
+            return a;
+        };
+        log(o(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,
@@ -150,16 +150,64 @@ 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);
+            var f = console.log(typeof f);
         }
         a();
     }
     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,
@@ -176,8 +224,7 @@ issue_4489: {
         console.log(k);
     }
     expect: {
-        !(A = 0);
-        for (var k in true);
+        for (var k in !(A = 0));
         console.log(k);
     }
     expect_stdout: "undefined"
@@ -202,8 +249,7 @@ issue_4517: {
     expect: {
         console.log(function() {
             var a = 2;
-            A = a;
-            return A + typeof !1;
+            return (A = a) + typeof !1;
         }());
     }
     expect_stdout: "2boolean"
@@ -234,7 +280,7 @@ issue_4736: {
         (function() {
             (function() {
                 0,
-                console.log(1073741824);
+                console.log(1 << 30);
             })();
         })();
     }
@@ -251,18 +297,18 @@ 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;
-        for (k in o)
+        var k, log = console.log;
+        for (k in void 0)
             throw "FAIL";
-        console.log("PASS");
+        log("PASS");
     }
     expect_stdout: "PASS"
 }
@@ -288,8 +334,7 @@ issue_4859: {
     }
     expect: {
         (function f(a) {
-            var d = 1 / 0, d = Infinity;
-            console.log(d);
+            console.log(2 + 1 / 0);
             return f;
         })();
     }
@@ -361,9 +406,9 @@ issue_4893_2: {
     expect: {
         try{
             (function() {
-                var b;
-                b = null;
-                b.p += 42;
+                var a;
+                a = null;
+                a.p += 42;
             })();
         } catch (e) {
             console.log("PASS");
@@ -395,3 +440,166 @@ 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]"
+}
+
+issue_5378: {
+    options = {
+        hoist_vars: true,
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 2;
+        while (a--)
+            (function() {
+                var b;
+                var c;
+                while (console.log(b));
+                --b;
+            })();
+    }
+    expect: {
+        var a = 2;
+        while (a--) {
+            b = void 0;
+            var b, c;
+            while (console.log(b));
+            --b;
+        }
+    }
+    expect_stdout: [
+        "undefined",
+        "undefined",
+    ]
+}
+
+issue_5411_1: {
+    options = {
+        collapse_vars: true,
+        dead_code: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "PASS";
+        b++;
+        b = a;
+        var b = b, c = c && c[b];
+        console.log(b);
+    }
+    expect: {
+        var b, c, a = "PASS";
+        b++;
+        b = a;
+        c = c && c[b];
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5411_2: {
+    options = {
+        collapse_vars: true,
+        dead_code: true,
+        evaluate: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        b++;
+        b = a;
+        var b = b, c = c && c[b];
+        console.log(b);
+    }
+    expect: {
+        var b, c;
+        b++;
+        b = "PASS",
+        c = c && c[b];
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5411_3: {
+    options = {
+        collapse_vars: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = console;
+        a++;
+        var a = A = a;
+        console.log(A);
+    }
+    expect: {
+        var a = console;
+        a = A = ++a;
+        console.log(A);
+    }
+    expect_stdout: "NaN"
+}

test/compress/ie.js

@@ -2631,13 +2631,14 @@ issue_3999: {
     ]
 }
 
-issue_4001: {
+issue_4001_1: {
     options = {
         collapse_vars: true,
         ie: true,
         inline: true,
         reduce_vars: true,
         sequences: true,
+        side_effects: false,
         toplevel: true,
         unused: true,
     }
@@ -2660,7 +2661,42 @@ issue_4001: {
             return a;
         }
         var a;
-        console.log((a = 42, void f()[42], void function a() {}));
+        console.log((a = 42, f()[42], void f, void function a() {}));
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4001_2: {
+    options = {
+        collapse_vars: true,
+        ie: true,
+        inline: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a) {
+            function f() {
+                return a;
+                var b;
+            }
+            var c = f();
+            (function g() {
+                c[42];
+                f;
+            })();
+            (function a() {});
+        }(42));
+    }
+    expect: {
+        function f() {
+            return a;
+        }
+        var a;
+        console.log((a = 42, void f()[42]));
     }
     expect_stdout: "undefined"
 }
@@ -3109,9 +3145,9 @@ issue_5081_call: {
         }));
     }
     expect: {
-        function f(b) {
+        function f(a) {
             // IE5-10: TypeError: Function expected
-            return b(b = "A") + (b += "SS");
+            return a(a = "A") + (a += "SS");
         }
         console.log(f(function() {
             return "P";
@@ -3161,8 +3197,8 @@ issue_5081_property_access: {
         console.log(f({ A: "P" }));
     }
     expect: {
-        function f(b) {
-            return b[b = "A"] + (b += "SS");
+        function f(a) {
+            return a[a = "A"] + (a += "SS");
         }
         // IE9-11: undefinedASS
         console.log(f({ A: "P" }));
@@ -3192,3 +3228,249 @@ issue_5081_property_access_ie: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5269_1: {
+    options = {
+        ie: false,
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        do {
+            (function() {
+                try {
+                    throw "PASS";
+                } catch (e) {
+                    console.log(e);
+                }
+            })();
+        } while (!console);
+    }
+    expect: {
+        "use strict";
+        do {
+            try {
+                throw "PASS";
+            } catch (e) {
+                console.log(e);
+            }
+        } while (!console);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5269_1_ie: {
+    options = {
+        ie: true,
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        do {
+            (function() {
+                try {
+                    throw "PASS";
+                } catch (e) {
+                    console.log(e);
+                }
+            })();
+        } while (!console);
+    }
+    expect: {
+        "use strict";
+        do {
+            try {
+                throw "PASS";
+            } catch (e) {
+                console.log(e);
+            }
+        } while (!console);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5269_2: {
+    options = {
+        ie: false,
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        for (var i = 0; i < 2; i++)
+            (function() {
+                console.log(e);
+                try {
+                    console;
+                } catch (e) {
+                    var e = "FAIL 1";
+                }
+                e = "FAIL 2";
+                console;
+            })();
+    }
+    expect: {
+        for (var i = 0; i < 2; i++) {
+            e = void 0;
+            console.log(e);
+            try {
+                console;
+            } catch (e) {
+                var e = "FAIL 1";
+            }
+            e = "FAIL 2";
+            console;
+        }
+    }
+    expect_stdout: [
+        "undefined",
+        "undefined",
+    ]
+}
+
+issue_5269_2_ie: {
+    options = {
+        ie: true,
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        for (var i = 0; i < 2; i++)
+            (function() {
+                console.log(e);
+                try {
+                    console;
+                } catch (e) {
+                    var e = "FAIL 1";
+                }
+                e = "FAIL 2";
+                console;
+            })();
+    }
+    expect: {
+        for (var i = 0; i < 2; i++) {
+            e = void 0;
+            console.log(e);
+            try {
+                console;
+            } catch (e) {
+                var e = "FAIL 1";
+            }
+            e = "FAIL 2";
+            console;
+        }
+    }
+    expect_stdout: [
+        "undefined",
+        "undefined",
+    ]
+}
+
+issue_5269_3: {
+    options = {
+        ie: false,
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        e = "foo";
+        for (var i = 0; i < 2; i++)
+            (function() {
+                console.log(e);
+                try {
+                    console;
+                } catch (e) {
+                    e = "FAIL";
+                }
+                e = "bar";
+                console;
+            })();
+    }
+    expect: {
+        e = "foo";
+        for (var i = 0; i < 2; i++) {
+            console.log(e);
+            try {
+                console;
+            } catch (e) {
+                e = "FAIL";
+            }
+            e = "bar";
+            console;
+        }
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_5269_3_ie: {
+    options = {
+        ie: true,
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        e = "foo";
+        for (var i = 0; i < 2; i++)
+            (function() {
+                console.log(e);
+                try {
+                    console;
+                } catch (e) {
+                    e = "FAIL";
+                }
+                e = "bar";
+                console;
+            })();
+    }
+    expect: {
+        e = "foo";
+        for (var i = 0; i < 2; i++) {
+            console.log(e);
+            try {
+                console;
+            } catch (e) {
+                e = "FAIL";
+            }
+            e = "bar";
+            console;
+        }
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_5350: {
+    options = {
+        ie: false,
+        properties: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(typeof f, [ 42, function f() {} ][0]);
+    }
+    expect: {
+        console.log(typeof f, 42);
+    }
+    expect_stdout: "undefined 42"
+}
+
+issue_5350_ie: {
+    options = {
+        ie: true,
+        properties: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(typeof f, [ 42, function f() {} ][0]);
+    }
+    expect: {
+        console.log(typeof f, (function f() {}, 42));
+    }
+    expect_stdout: "undefined 42"
+}

test/compress/if_return.js

@@ -327,7 +327,7 @@ issue_512: {
     }
 }
 
-if_var_return: {
+if_var_return_1: {
     options = {
         conditionals: true,
         if_return: true,
@@ -373,6 +373,76 @@ if_var_return: {
     }
 }
 
+if_var_return_2: {
+    options = {
+        conditionals: true,
+        if_return: true,
+        sequences: true,
+    }
+    input: {
+        (function() {
+            var a = w();
+            if (x())
+                return y();
+            z();
+        })();
+    }
+    expect: {
+        (function() {
+            var a = w();
+            return x() ? y() : (z(), void 0);
+        })();
+    }
+}
+
+if_var_retrn_3: {
+    options = {
+        conditionals: true,
+        if_return: true,
+        sequences: true,
+    }
+    input: {
+        f(function() {
+            var a = w();
+            if (x())
+                return y(a);
+            z();
+        });
+    }
+    expect: {
+        f(function() {
+            var a = w();
+            if (x())
+                return y(a);
+            z();
+        });
+    }
+}
+
+if_var_return_4: {
+    options = {
+        conditionals: true,
+        if_return: true,
+        sequences: true,
+    }
+    input: {
+        function f() {
+            if (u())
+                return v();
+            var a = w();
+            if (x())
+                return y();
+            z();
+        }
+    }
+    expect: {
+        function f() {
+            return u() ? v() : (a = w(), x() ? y() : (z(), void 0));
+            var a;
+        }
+    }
+}
+
 if_if_return_return: {
     options = {
         conditionals: true,
@@ -545,7 +615,36 @@ if_body_return_3: {
     ]
 }
 
-issue_3600: {
+issue_3600_1: {
+    options = {
+        if_return: true,
+        inline: 3,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var c = 0;
+        (function() {
+            if ([ ][c++]); else return;
+            return void function() {
+                var b = --b, a = c = 42;
+                return c;
+            }();
+        })();
+        console.log(c);
+    }
+    expect: {
+        var c = 0;
+        (function() {
+            if ([][c++]) b = --b, c = 42;
+            var b;
+        })();
+        console.log(c);
+    }
+    expect_stdout: "1"
+}
+
+issue_3600_2: {
     options = {
         if_return: true,
         inline: true,
@@ -566,7 +665,9 @@ issue_3600: {
     expect: {
         var c = 0;
         (function() {
-            if ([][c++]) b = --b, c = 42;
+            if ([][c++])
+                b = --b,
+                c = 42;
             var b;
         })();
         console.log(c);
@@ -597,7 +698,9 @@ iife_if_return_simple: {
 
 nested_if_break: {
     options = {
+        conditionals: true,
         if_return: true,
+        side_effects: true,
     }
     input: {
         for (var i = 0; i < 3; i++)
@@ -608,8 +711,7 @@ nested_if_break: {
     }
     expect: {
         for (var i = 0; i < 3; i++)
-            L1: if ("number" == typeof i)
-                if (0 !== i) console.log(i);
+            L1: "number" == typeof i && 0 !== i && console.log(i);
     }
     expect_stdout: [
         "1",
@@ -648,11 +750,11 @@ nested_if_continue: {
         function f(n) {
             for (var i = 0;
                 "number" == typeof n
-                    && (0 !== n
-                        ? 1 !== n
-                            ? i++
-                            : console.log("odd", i)
-                        : console.log("even", i)),
+                    && (0 === n
+                        ? console.log("even", i)
+                        : 1 === n
+                        ? console.log("odd", i)
+                        : i++),
                 0 <= (n -= 2););
         }
         f(37);

test/compress/imports.js

@@ -106,6 +106,22 @@ drop_unused: {
     }
 }
 
+drop_side_effect_free: {
+    options = {
+        imports: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        import foo from "bar";
+        var a = foo;
+    }
+    expect: {
+        import "bar";
+    }
+}
+
 mangle: {
     rename = false
     mangle = {

test/compress/indentation.js

@@ -0,0 +1,100 @@
+numeric: {
+    beautify = {
+        beautify: true,
+        indent_start: 1,
+        indent_level: 3,
+    }
+    input: {
+        switch (42) {
+          case null:
+            console.log("FAIL");
+        }
+        console.log("PASS");
+    }
+    expect_exact: [
+        " switch (42) {",
+        "  case null:",
+        '    console.log("FAIL");',
+        " }",
+        "",
+        ' console.log("PASS");',
+    ]
+    expect_stdout: "PASS"
+}
+
+spaces: {
+    beautify = {
+        beautify: true,
+        indent_start: " ",
+        indent_level: "   ",
+    }
+    input: {
+        switch (42) {
+          case null:
+            console.log("FAIL");
+        }
+        console.log("PASS");
+    }
+    expect_exact: [
+        " switch (42) {",
+        "  case null:",
+        '    console.log("FAIL");',
+        " }",
+        "",
+        ' console.log("PASS");',
+    ]
+    expect_stdout: "PASS"
+}
+
+tabs: {
+    beautify = {
+        beautify: true,
+        indent_start: "\t",
+        indent_level: "\t",
+    }
+    input: {
+        switch (42) {
+          case null:
+            console.log("FAIL");
+        }
+        console.log("PASS");
+    }
+    expect_exact: [
+        "\tswitch (42) {",
+        "\tcase null:",
+        '\t\tconsole.log("FAIL");',
+        "\t}",
+        "",
+        '\tconsole.log("PASS");',
+    ]
+    expect_stdout: "PASS"
+}
+
+mixed: {
+    beautify = {
+        beautify: true,
+        indent_start: "\n",
+        indent_level: "       \t",
+    }
+    input: {
+        switch (42) {
+          case null:
+            console.log("FAIL");
+        }
+        console.log("PASS");
+    }
+    expect_exact: [
+        "",
+        "switch (42) {",
+        "",
+        "    case null:",
+        "",
+        '       \tconsole.log("FAIL");',
+        "",
+        "}",
+        "",
+        "",
+        'console.log("PASS");',
+    ]
+    expect_stdout: "PASS"
+}

test/compress/issue-1052.js

@@ -4,22 +4,21 @@ multiple_functions: {
         if_return: true,
     }
     input: {
-        ( function() {
-            if ( !window ) {
+        (function() {
+            if (!window)
                 return;
-            }
             function f() {}
             function g() {}
-        } )();
+        })();
     }
     expect: {
-        ( function() {
+        (function() {
             // NOTE: other compression steps will reduce this
             // down to just `window`.
-            if ( !window );
+            if (!window);
             function f() {}
             function g() {}
-        } )();
+        })();
     }
 }
 
@@ -29,18 +28,17 @@ single_function: {
         if_return: true,
     }
     input: {
-        ( function() {
-            if ( !window ) {
+        (function() {
+            if (!window)
                 return;
-            }
             function f() {}
-        } )();
+        })();
     }
     expect: {
-        ( function() {
-            if ( !window );
+        (function() {
+            if (!window);
             function f() {}
-        } )();
+        })();
     }
 }
 
@@ -50,28 +48,26 @@ deeply_nested: {
         if_return: true,
     }
     input: {
-        ( function() {
-            if ( !window ) {
+        (function() {
+            if (!window)
                 return;
-            }
             function f() {}
             function g() {}
-            if ( !document ) {
+            if (!document)
                 return;
-            }
             function h() {}
-        } )();
+        })();
     }
     expect: {
-        ( function() {
+        (function() {
             // NOTE: other compression steps will reduce this
             // down to just `window`.
-            if ( window )
-                if ( !document );
+            if (!window);
+            else if (!document);
             function f() {}
             function g() {}
             function h() {}
-        } )();
+        })();
     }
 }
 
@@ -81,18 +77,18 @@ not_hoisted_when_already_nested: {
         if_return: true,
     }
     input: {
-        ( function() {
-            if ( !window ) {
+        (function() {
+            if (!window)
                 return;
-            }
-            if ( foo ) function f() {}
-        } )();
+            if (foo) function f() {}
+        })();
     }
     expect: {
-        ( function() {
-            if ( window )
-                if ( foo ) function f() {}
-        } )();
+        (function() {
+            if (!window);
+            else if (foo)
+                function f() {}
+        })();
     }
 }
 
@@ -104,15 +100,19 @@ defun_if_return: {
     input: {
         function e() {
             function f() {}
-            if (!window) return;
-            else function g() {}
+            if (!window)
+                return;
+            else
+                function g() {}
             function h() {}
         }
     }
     expect: {
         function e() {
             function f() {}
-            if (window) function g() {}
+            if (!window);
+            else
+                function g() {}
             function h() {}
         }
     }
@@ -126,8 +126,10 @@ defun_hoist_funs: {
     input: {
         function e() {
             function f() {}
-            if (!window) return;
-            else function g() {}
+            if (!window)
+                return;
+            else
+                function g() {}
             function h() {}
         }
     }
@@ -136,7 +138,7 @@ defun_hoist_funs: {
             function f() {}
             function g() {}
             function h() {}
-            if (window);
+            if (!window);
         }
     }
 }
@@ -149,15 +151,18 @@ defun_else_if_return: {
     input: {
         function e() {
             function f() {}
-            if (window) function g() {}
-            else return;
+            if (window)
+                function g() {}
+            else
+                return;
             function h() {}
         }
     }
     expect: {
         function e() {
             function f() {}
-            if (window) function g() {}
+            if (window)
+                function g() {}
             function h() {}
         }
     }

test/compress/issue-1447.js

@@ -40,6 +40,9 @@ conditional_false_stray_else_in_loop: {
             console.log(i);
         }
     }
-    expect_exact: "for(var i=1;i<=4;++i)if(!(i<=2))console.log(i);"
-    expect_stdout: true
+    expect_exact: "for(var i=1;i<=4;++i)if(i<=2);else console.log(i);"
+    expect_stdout: [
+        "3",
+        "4",
+    ]
 }

test/compress/issue-1704.js

@@ -356,6 +356,7 @@ mangle_catch_redef_3: {
         try {
             throw 0;
         } catch (o) {
+            // prints "FAIL" if inlined on Node.js v4-
             (function() {
                 function f() {
                     o = "FAIL";
@@ -366,7 +367,8 @@ mangle_catch_redef_3: {
         console.log(o);
     }
     expect_exact: 'var o="PASS";try{throw 0}catch(o){(function(){function c(){o="FAIL"}c(),c()})()}console.log(o);'
-    expect_stdout: true
+    expect_stdout: "PASS"
+    node_version: ">=6"
 }
 
 mangle_catch_redef_3_toplevel: {
@@ -379,6 +381,7 @@ mangle_catch_redef_3_toplevel: {
         try {
             throw 0;
         } catch (o) {
+            // prints "FAIL" if inlined on Node.js v4-
             (function() {
                 function f() {
                     o = "FAIL";
@@ -389,7 +392,8 @@ mangle_catch_redef_3_toplevel: {
         console.log(o);
     }
     expect_exact: 'var c="PASS";try{throw 0}catch(c){(function(){function o(){c="FAIL"}o(),o()})()}console.log(c);'
-    expect_stdout: true
+    expect_stdout: "PASS"
+    node_version: ">=6"
 }
 
 mangle_catch_redef_3_ie8: {
@@ -402,6 +406,7 @@ mangle_catch_redef_3_ie8: {
         try {
             throw 0;
         } catch (o) {
+            // prints "FAIL" if inlined on Node.js v4-
             (function() {
                 function f() {
                     o = "FAIL";
@@ -412,7 +417,8 @@ mangle_catch_redef_3_ie8: {
         console.log(o);
     }
     expect_exact: 'var o="PASS";try{throw 0}catch(o){(function(){function c(){o="FAIL"}c(),c()})()}console.log(o);'
-    expect_stdout: true
+    expect_stdout: "PASS"
+    node_version: ">=6"
 }
 
 mangle_catch_redef_3_ie8_toplevel: {
@@ -425,6 +431,7 @@ mangle_catch_redef_3_ie8_toplevel: {
         try {
             throw 0;
         } catch (o) {
+            // prints "FAIL" if inlined on Node.js v4-
             (function() {
                 function f() {
                     o = "FAIL";
@@ -435,5 +442,6 @@ mangle_catch_redef_3_ie8_toplevel: {
         console.log(o);
     }
     expect_exact: 'var c="PASS";try{throw 0}catch(c){(function(){function o(){c="FAIL"}o(),o()})()}console.log(c);'
-    expect_stdout: true
+    expect_stdout: "PASS"
+    node_version: ">=6"
 }

test/compress/issue-640.js

@@ -317,7 +317,35 @@ iife: {
         typeof function g() {}();
     }
     expect: {
-        x = 42, function a() {}(), function b() {}(), function c() {}(),
-        function d() {}(), function e() {}(), function f() {}(), typeof function g() {}();
+        x = 42,
+        function a() {}(),
+        !function b() {}(),
+        ~function c() {}(),
+        +function d() {}(),
+        -function e() {}(),
+        void function f() {}(),
+        typeof function g() {}();
+    }
+}
+
+iife_drop_side_effect_free: {
+    options = {
+        expression: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        x = 42;
+        (function a() {})();
+        !function b() {}();
+        ~function c() {}();
+        +function d() {}();
+        -function e() {}();
+        void function f() {}();
+        typeof function g() {}();
+    }
+    expect: {
+        x = 42,
+        typeof void 0;
     }
 }

test/compress/issue-892.js

@@ -1,6 +1,4 @@
 dont_mangle_arguments: {
-    mangle = {
-    };
     options = {
         booleans: true,
         comparisons: true,
@@ -21,12 +19,13 @@ dont_mangle_arguments: {
         side_effects: true,
         unused: true,
     }
+    mangle = {}
     input: {
         (function(){
             var arguments = arguments, not_arguments = 9;
             console.log(not_arguments, arguments);
-        })(5,6,7);
+        })(5, 6, 7);
     }
-    expect_exact: "(function(){var arguments=arguments,o=9;console.log(o,arguments)})(5,6,7);"
+    expect_exact: "(function(){var arguments,o=9;console.log(o,arguments)})(5,6,7);"
     expect_stdout: true
 }

test/compress/issue-979.js

@@ -1,4 +1,4 @@
-issue979_reported: {
+reported: {
     options = {
         booleans: true,
         comparisons: true,
@@ -17,29 +17,26 @@ issue979_reported: {
     }
     input: {
         function f1() {
-            if (a == 1 || b == 2) {
+            if (a == 1 || b == 2)
                 foo();
-            }
         }
         function f2() {
-            if (!(a == 1 || b == 2)) {
-            }
-            else {
+            if (!(a == 1 || b == 2));
+            else
                 foo();
-            }
         }
     }
     expect: {
         function f1() {
-            1!=a&&2!=b||foo();
+            1 != a && 2 != b || foo();
         }
         function f2() {
-            1!=a&&2!=b||foo();
+            1 != a && 2 != b || foo();
         }
     }
 }
 
-issue979_test_negated_is_best: {
+test_negated_is_best: {
     options = {
         booleans: true,
         comparisons: true,
@@ -58,53 +55,47 @@ issue979_test_negated_is_best: {
     }
     input: {
         function f3() {
-            if (a == 1 | b == 2) {
+            if (a == 1 | b == 2)
                 foo();
-            }
         }
         function f4() {
-            if (!(a == 1 | b == 2)) {
-            }
-            else {
+            if (!(a == 1 | b == 2));
+            else
                 foo();
-            }
         }
         function f5() {
-            if (a == 1 && b == 2) {
+            if (a == 1 && b == 2)
                 foo();
-            }
         }
         function f6() {
-            if (!(a == 1 && b == 2)) {
-            }
-            else {
+            if (!(a == 1 && b == 2));
+            else
                 foo();
-            }
         }
         function f7() {
-            if (a == 1 || b == 2) {
+            if (a == 1 || b == 2)
                 foo();
-            }
-            else {
+            else
                 return bar();
-            }
         }
     }
     expect: {
         function f3() {
-            1==a|2==b&&foo();
+            1 == a | 2 == b && foo();
         }
         function f4() {
-            1==a|2==b&&foo();
+            1 == a | 2 == b && foo();
         }
         function f5() {
-            1==a&&2==b&&foo();
+            1 == a && 2 == b && foo();
         }
         function f6() {
-            1!=a||2!=b||foo();
+            1 == a && 2 == b && foo();
         }
         function f7() {
-            if(1!=a&&2!=b)return bar();foo()
+            if (1 != a && 2 != b)
+                return bar();
+            foo();
         }
     }
 }

test/compress/join_vars.js

@@ -489,6 +489,160 @@ 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"
+}
+
+inilne_for: {
+    options = {
+        inline: true,
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function() {
+            for (; console.log("PASS"););
+        };
+        a();
+    }
+    expect: {
+        for (; console.log("PASS"););
+    }
+    expect_stdout: "PASS"
+}
+
+inilne_var: {
+    options = {
+        inline: true,
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        A = "PASS";
+        var a = function() {
+            var b = A;
+            for (b in console.log(b));
+        };
+        a();
+    }
+    expect: {
+        A = "PASS";
+        var b = A;
+        for (b in console.log(b));
+    }
+    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,
@@ -990,7 +1144,7 @@ conditional_assignments_3: {
     expect_stdout: "PASS"
 }
 
-issue_3856: {
+issue_3856_1: {
     options = {
         booleans: true,
         conditionals: true,
@@ -1015,9 +1169,46 @@ issue_3856: {
         console.log(function() {
             (function() {
                 var a, b;
-                if (a) return a, 1;
-                for (a = 0; !console;);
-                return 0;
+                if (a) a;
+                else {
+                    a = 0;
+                    for (; !console;);
+                }
+            })();
+        }());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_3856_2: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        if_return: true,
+        join_vars: true,
+        passes: 2,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(function() {
+            (function() {
+                var a;
+                if (!a) {
+                    a = 0;
+                    for (var b; !console;);
+                    return 0;
+                }
+                if (a) return 1;
+            })();
+        }());
+    }
+    expect: {
+        console.log(function() {
+            (function() {
+                var a, b;
+                if (!a)
+                    for (a = 0; !console;);
             })();
         }());
     }
@@ -1172,10 +1363,7 @@ assign_sequence_var: {
         console.log(a, b, c);
     }
     expect: {
-        var a = 0, b = 1;
-        console.log(a),
-        a++;
-        var b = 2, c = 3;
+        var a = 0, b = 1, c = (console.log(a), a++, b = 2, 3);
         console.log(a, b, c);
     }
     expect_stdout: [
@@ -1183,3 +1371,26 @@ 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

@@ -181,10 +181,10 @@ issue_2203_2: {
             a: "FAIL",
             b: function() {
                 return function() {
-                    return (String, (Object, function() {
+                    return (Object, function() {
                         return this;
-                    }())).a;
-                }();
+                    }()).a;
+                }(String);
             }
         }.b());
     }
@@ -925,6 +925,28 @@ duplicate_lambda_defun_name_2: {
     expect_stdout: "0"
 }
 
+function_argument_mangle: {
+    mangle = {
+        keep_fargs: true,
+        toplevel: true,
+    }
+    input: {
+        A = "PASS";
+        var a = A;
+        (function(o) {
+            console.log(a);
+        })("FAIL");
+    }
+    expect: {
+        A = "PASS";
+        var n = A;
+        (function(o) {
+            console.log(n);
+        })("FAIL");
+    }
+    expect_stdout: "PASS"
+}
+
 function_name_mangle: {
     options = {
         keep_fargs: false,
@@ -1217,6 +1239,7 @@ issues_3267_1: {
         evaluate: true,
         inline: true,
         keep_fargs: false,
+        negate_iife: true,
         reduce_vars: true,
         sequences: true,
         side_effects: true,

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) {
-            if (bar) break out;
+        while (foo) {
+            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) {
-            x();
-            y();
+        out: while (42) {
+            console.log("PASS");
             break out;
-            z();
-            k();
+            console.log("FAIL");
         }
     };
     expect: {
-        out: while (foo) {
-            x();
-            y();
-            break out;
+        while (42) {
+            console.log("PASS");
+            break;
         }
     }
+    expect_stdout: "PASS"
 }
 
 issue_4466_1: {

test/compress/let.js

@@ -1,4 +1,4 @@
-retain_block: {
+retain_block_1: {
     options = {}
     input: {
         "use strict";
@@ -20,6 +20,94 @@ retain_block: {
     node_version: ">=4"
 }
 
+retain_block_2: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        {
+            var a;
+            let a;
+        }
+    }
+    expect: {
+        "use strict";
+        {
+            var a;
+            let a;
+        }
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+retain_block_2_mangle: {
+    rename = true
+    mangle = {
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        {
+            var a;
+            let a;
+        }
+    }
+    expect: {
+        "use strict";
+        {
+            var t;
+            let t;
+        }
+    }
+}
+
+retain_block_3: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        {
+            let a;
+            var a;
+        }
+    }
+    expect: {
+        "use strict";
+        {
+            let a;
+            var a;
+        }
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+retain_block_3_mangle: {
+    rename = true
+    mangle = {
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        {
+            let a;
+            var a;
+        }
+    }
+    expect: {
+        "use strict";
+        {
+            let t;
+            var t;
+        }
+    }
+}
+
 retain_assignment: {
     options = {
         dead_code: true,
@@ -182,8 +270,8 @@ merge_vars_3: {
             var b = console;
             console.log(typeof b);
         }
-        var a = 1;
-        console.log(typeof a);
+        var b = 1;
+        console.log(typeof b);
     }
     expect_stdout: [
         "object",
@@ -192,6 +280,38 @@ merge_vars_3: {
     node_version: ">=4"
 }
 
+merge_vars_4: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        var a = 1;
+        console.log(typeof a);
+        {
+            var b = console;
+            console.log(typeof b);
+            let a = 0;
+        }
+    }
+    expect: {
+        "use strict";
+        var a = 1;
+        console.log(typeof a);
+        {
+            var b = console;
+            console.log(typeof b);
+            let a = 0;
+        }
+    }
+    expect_stdout: [
+        "number",
+        "object",
+    ]
+    node_version: ">=4"
+}
+
 use_before_init_1: {
     options = {
         evaluate: true,
@@ -792,8 +912,7 @@ do_if_continue_1: {
     expect: {
         "use strict";
         do {
-            if (!console);
-            else {
+            if (console) {
                 console.log("PASS");
                 {
                     let a = 0;
@@ -826,8 +945,7 @@ do_if_continue_2: {
     expect: {
         "use strict";
         do {
-            if (!console);
-            else {
+            if (console) {
                 console.log("FAIL");
                 {
                     let a = 0;
@@ -966,12 +1084,10 @@ issue_4202: {
         "use strict";
         {
             let o = {};
-            (function() {
-                function f() {
-                    o.p = 42;
-                }
-                f(f);
-            })();
+            function f() {
+                o.p = 42;
+            }
+            f(f);
             console.log(o.p++);
         }
     }
@@ -1549,11 +1665,9 @@ issue_4438: {
     expect: {
         "use strict";
         function f() {
-            if (!console)
-                ;
-            else {
+            if (console) {
                 let a = console.log;
-                a("PASS");
+                void a("PASS");
             }
         }
         f();
@@ -1639,6 +1753,7 @@ issue_4689: {
 
 issue_4691: {
     options = {
+        conditionals: true,
         if_return: true,
         toplevel: true,
     }
@@ -1747,3 +1862,161 @@ issue_4985: {
     expect_stdout: "undefined"
     node_version: ">=4"
 }
+
+issue_5240: {
+    options = {
+        inline: true,
+    }
+    input: {
+        "use strict";
+        function f() {
+            if (console) {
+                let g = function() {
+                    e;
+                }, e;
+                (function() {
+                    if (console) {
+                        console.log(e);
+                        var e = "FAIL";
+                    }
+                })(console.log(e));
+            }
+        }
+        f();
+    }
+    expect: {
+        "use strict";
+        function f() {
+            if (console) {
+                let g = function() {
+                    e;
+                }, e;
+                (function() {
+                    if (console) {
+                        console.log(e);
+                        var e = "FAIL";
+                    }
+                })(console.log(e));
+            }
+        }
+        f();
+    }
+    expect_stdout: [
+        "undefined",
+        "undefined",
+    ]
+    node_version: ">=4"
+}
+
+issue_5254: {
+    options = {
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        do {
+            (function() {
+                let a = console.log;
+                a && a("foo");
+            })();
+        } while (console.log("bar"));
+    }
+    expect: {
+        "use strict";
+        do {
+            let a = console.log;
+            a && a("foo");
+        } while (console.log("bar"));
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    node_version: ">=4"
+}
+
+issue_5260: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        "use strict";
+        var a = "foo", o;
+        while (console.log("bar"));
+        o = {
+            baz: function(b) {
+                console.log(a, b);
+            },
+        };
+        for (let a in o)
+            o[a](a);
+    }
+    expect: {
+        "use strict";
+        var a = "foo", o;
+        while (console.log("bar"));
+        o = {
+            baz: function(b) {
+                console.log(a, b);
+            },
+        };
+        for (let a in o)
+            o[a](a);
+    }
+    expect_stdout: [
+        "bar",
+        "foo baz",
+    ]
+    node_version: ">=4"
+}
+
+issue_5319: {
+    options = {
+        collapse_vars: true,
+        merge_vars: true,
+    }
+    input: {
+        "use strict";
+        (function(a, c) {
+            var b = a, c = b;
+            {
+                let a = c;
+                console.log(c());
+            }
+        })(function() {
+            return "PASS";
+        });
+    }
+    expect: {
+        "use strict";
+        (function(a, c) {
+            var b = a, c;
+            {
+                let a = c = b;
+                console.log(c());
+            }
+        })(function() {
+            return "PASS";
+        });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5338: {
+    options = {
+        unused: true,
+    }
+    input: {
+        "use strict";
+        let a = a;
+    }
+    expect: {
+        "use strict";
+        a;
+        let a;
+    }
+    expect_stdout: ReferenceError("a is not defined")
+    node_version: ">=4"
+}

test/compress/max_line_len.js

@@ -37,6 +37,51 @@ just_enough: {
     expect_warnings: []
 }
 
+drop_semicolon: {
+    beautify = {
+        max_line_len: 5,
+        semicolons: true,
+    }
+    input: {
+        var a;
+        console.log(a || 42);
+    }
+    expect_exact: [
+        "var a",
+        "console.log(",
+        "a||42",
+        ");",
+    ]
+    expect_stdout: "42"
+    expect_warnings: [
+        "WARN: Output exceeds 5 characters",
+    ]
+}
+
+template_newline: {
+    beautify = {
+        max_line_len: 2,
+    }
+    input: {
+        console.log(`foo
+bar`);
+    }
+    expect_exact: [
+        "console.log(",
+        "`foo",
+        "bar`",
+        ");",
+    ]
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    expect_warnings: [
+        "WARN: Output exceeds 2 characters",
+    ]
+    node_version: ">=4"
+}
+
 issue_304: {
     beautify = {
         max_line_len: 10,

test/compress/merge_vars.js

@@ -19,11 +19,11 @@ merge: {
     expect: {
         var a = "foo";
         console.log(a);
-        function f(c) {
-            var c;
-            console.log(c);
-            c = "bar";
-            console.log(c);
+        function f(b) {
+            var b;
+            console.log(b);
+            b = "bar";
+            console.log(b);
         }
         f("baz");
         var d = "moo";
@@ -56,17 +56,17 @@ merge_toplevel: {
         console.log(d);
     }
     expect: {
-        var d = "foo";
-        console.log(d);
-        function f(c) {
-            var c;
-            console.log(c);
-            c = "bar";
-            console.log(c);
+        var a = "foo";
+        console.log(a);
+        function f(b) {
+            var b;
+            console.log(b);
+            b = "bar";
+            console.log(b);
         }
         f("baz");
-        var d = "moo";
-        console.log(d);
+        var a = "moo";
+        console.log(a);
     }
     expect_stdout: [
         "foo",
@@ -94,16 +94,16 @@ segment: {
         console.log(d);
     }
     expect: {
-        var d = "foo";
-        console.log(d);
-        for (var c, i = 0; i < 1; i++) {
-            var c = "bar";
-            console.log(c);
-            c = "baz";
-            console.log(c);
+        var a = "foo";
+        console.log(a);
+        for (var b, i = 0; i < 1; i++) {
+            var b = "bar";
+            console.log(b);
+            b = "baz";
+            console.log(b);
         }
-        var d = "moo";
-        console.log(d);
+        var a = "moo";
+        console.log(a);
     }
     expect_stdout: [
         "foo",
@@ -169,6 +169,158 @@ conditional_branch: {
     expect_stdout: "PASS"
 }
 
+conditional_chain_1: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a, b) {
+            var c, d;
+            if (a && (c = a))
+                console.log(c);
+            else
+                b || (d = b) ? console.log("foo") : console.log(d);
+        }
+        f("", null);
+        f("", true);
+        f(42, null);
+        f(42, true);
+    }
+    expect: {
+        function f(a, b) {
+            var a, a;
+            if (a && (a = a))
+                console.log(a);
+            else
+                b || (a = b) ? console.log("foo") : console.log(a);
+        }
+        f("", null);
+        f("", true);
+        f(42, null);
+        f(42, true);
+    }
+    expect_stdout: [
+        "null",
+        "foo",
+        "42",
+        "42",
+    ]
+}
+
+conditional_chain_2: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a, b) {
+            var c, d;
+            if (a && (c = a))
+                console.log(c);
+            else
+                b || (d = b) ? console.log(c) : console.log(d);
+        }
+        f("", null);
+        f("", true);
+        f(42, null);
+        f(42, true);
+    }
+    expect: {
+        function f(a, b) {
+            var c, a;
+            if (a && (c = a))
+                console.log(c);
+            else
+                b || (a = b) ? console.log(c) : console.log(a);
+        }
+        f("", null);
+        f("", true);
+        f(42, null);
+        f(42, true);
+    }
+    expect_stdout: [
+        "null",
+        "undefined",
+        "42",
+        "42",
+    ]
+}
+
+conditional_chain_3: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a, b) {
+            var c, d;
+            if (a && (c = a) || b || (d = b))
+                console.log(c);
+            else
+                console.log(d);
+        }
+        f("", null);
+        f("", true);
+        f(42, null);
+        f(42, true);
+    }
+    expect: {
+        function f(a, b) {
+            var c, a;
+            if (a && (c = a) || b || (a = b))
+                console.log(c);
+            else
+                console.log(a);
+        }
+        f("", null);
+        f("", true);
+        f(42, null);
+        f(42, true);
+    }
+    expect_stdout: [
+        "null",
+        "undefined",
+        "42",
+        "42",
+    ]
+}
+
+conditional_chain_4: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a, b) {
+            var c, d;
+            if (a && b ? c = a : d = b)
+                console.log(c);
+            else
+                console.log(d);
+        }
+        f("", null);
+        f("", true);
+        f(42, null);
+        f(42, true);
+    }
+    expect: {
+        function f(a, b) {
+            var c, d;
+            if (a && b ? c = a : d = b)
+                console.log(c);
+            else
+                console.log(d);
+        }
+        f("", null);
+        f("", true);
+        f(42, null);
+        f(42, true);
+    }
+    expect_stdout: [
+        "null",
+        "undefined",
+        "null",
+        "42",
+    ]
+}
+
 if_branch: {
     options = {
         merge_vars: true,
@@ -253,6 +405,7 @@ read_before_assign_1: {
         inline: true,
         merge_vars: true,
         sequences: true,
+        side_effects: true,
         toplevel: true,
     }
     input: {
@@ -298,6 +451,89 @@ read_before_assign_2: {
     expect_stdout: "PASS"
 }
 
+collapse_vars_1: {
+    options = {
+        collapse_vars: true,
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = a && a.p;
+        var b = "PASS";
+        var b = b && console.log(b);
+    }
+    expect: {
+        var a = a && a.p;
+        var a;
+        var a = (a = "PASS") && console.log(a);
+    }
+    expect_stdout: "PASS"
+}
+
+collapse_vars_2: {
+    options = {
+        collapse_vars: true,
+        merge_vars: true,
+    }
+    input: {
+        "use strict";
+        var log = console.log;
+        (function g(a) {
+            var b = a;
+            var c = Math.random();
+            var c = b;
+            log(c);
+            return c;
+        })("PASS");
+    }
+    expect: {
+        "use strict";
+        var log = console.log;
+        (function g(a) {
+            var a = a;
+            var c = Math.random();
+            var c;
+            log(c = a);
+            return c;
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+not_redefined: {
+    options = {
+        inline: true,
+        join_vars: true,
+        merge_vars: true,
+        reduce_vars: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        var log = console.log;
+        (function() {
+            return f("PASS");
+            function f(a) {
+                const b = a;
+                const c = log(b);
+                const d = log;
+                c && log(d);
+            }
+        })();
+    }
+    expect: {
+        var log = console.log;
+        (function() {
+            return a = "PASS",
+                a = log(a),
+                d = log,
+                void (a && log(d));
+            var a, d;
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
 issue_4103: {
     options = {
         merge_vars: true,
@@ -325,7 +561,7 @@ issue_4103: {
     ]
 }
 
-issue_4107: {
+issue_4107_1: {
     options = {
         keep_fargs: false,
         merge_vars: true,
@@ -342,6 +578,38 @@ issue_4107: {
         })();
         console.log(typeof a);
     }
+    expect: {
+        (function() {
+            (function(c) {
+                c = console || c;
+                console.log(typeof c);
+            })();
+        })();
+        console.log(typeof a);
+    }
+    expect_stdout: [
+        "object",
+        "undefined",
+    ]
+}
+
+issue_4107_2: {
+    options = {
+        keep_fargs: false,
+        merge_vars: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            function f(b, b, a) {
+                var d = 1 && c, c = console || a;
+                console.log(typeof c);
+            }
+            f();
+        })();
+        console.log(typeof a);
+    }
     expect: {
         (function() {
             (function(a) {
@@ -476,9 +744,9 @@ issue_4112: {
             try {
                 throw 42;
             } catch (e) {
-                var a = e;
-                for (e in a);
-                a = function() {};
+                var o = e;
+                for (e in o);
+                function a() {}
                 console.log(typeof a);
                 return a;
             }
@@ -538,12 +806,12 @@ cross_branch_1_1: {
     expect: {
         var a;
         function f() {
-            var y, y;
+            var x, x;
             if (a)
-                y = "foo";
-            console.log(y);
-            y = "bar";
-            console.log(y);
+                x = "foo";
+            console.log(x);
+            x = "bar";
+            console.log(x);
         }
         a = 0;
         f();
@@ -581,13 +849,13 @@ cross_branch_1_2: {
     expect: {
         var a;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
-                y = "foo";
-                console.log(y);
+                x = "foo";
+                console.log(x);
             }
-            y = "bar";
-            console.log(y);
+            x = "bar";
+            console.log(x);
         }
         a = 0;
         f();
@@ -624,13 +892,13 @@ cross_branch_1_3: {
     expect: {
         var a;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
-                y = "foo";
-                console.log(y);
-                y = "bar";
+                x = "foo";
+                console.log(x);
+                x = "bar";
             }
-            console.log(y);
+            console.log(x);
         }
         a = 0;
         f();
@@ -666,12 +934,12 @@ cross_branch_1_4: {
     expect: {
         var a;
         function f() {
-            var y, y;
-            y = "foo";
+            var x, x;
+            x = "foo";
             if (a)
-                console.log(y);
-            y = "bar";
-            console.log(y);
+                console.log(x);
+            x = "bar";
+            console.log(x);
         }
         a = 0;
         f();
@@ -751,12 +1019,12 @@ cross_branch_1_6: {
     expect: {
         var a;
         function f() {
-            var y, y;
-            y = "foo";
+            var x, x;
+            x = "foo";
             if (a) {
-                console.log(y);
-                y = "bar";
-                console.log(y);
+                console.log(x);
+                x = "bar";
+                console.log(x);
             }
         }
         a = 0;
@@ -835,12 +1103,12 @@ cross_branch_1_8: {
     expect: {
         var a;
         function f() {
-            var y, y;
-            y = "foo";
-            console.log(y);
+            var x, x;
+            x = "foo";
+            console.log(x);
             if (a) {
-                y = "bar";
-                console.log(y);
+                x = "bar";
+                console.log(x);
             }
         }
         a = 0;
@@ -877,12 +1145,12 @@ cross_branch_1_9: {
     expect: {
         var a;
         function f() {
-            var y, y;
-            y = "foo";
-            console.log(y);
-            y = "bar";
+            var x, x;
+            x = "foo";
+            console.log(x);
+            x = "bar";
             if (a)
-                console.log(y);
+                console.log(x);
         }
         a = 0;
         f();
@@ -924,14 +1192,14 @@ cross_branch_2a_1: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
                 if (b)
-                    y = "foo";
-                console.log(y);
+                    x = "foo";
+                console.log(x);
             }
-            y = "bar";
-            console.log(y);
+            x = "bar";
+            console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -980,14 +1248,14 @@ cross_branch_2a_2: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
-                y = "foo";
+                x = "foo";
                 if (b)
-                    console.log(y);
+                    console.log(x);
             }
-            y = "bar";
-            console.log(y);
+            x = "bar";
+            console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -1035,14 +1303,14 @@ cross_branch_2a_3: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
                 if (b)
-                    y = "foo";
-                console.log(y);
-                y = "bar";
+                    x = "foo";
+                console.log(x);
+                x = "bar";
             }
-            console.log(y);
+            console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -1092,15 +1360,15 @@ cross_branch_2a_4: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
                 if (b) {
-                    y = "foo";
-                    console.log(y);
+                    x = "foo";
+                    console.log(x);
                 }
-                y = "bar";
+                x = "bar";
             }
-            console.log(y);
+            console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -1148,14 +1416,14 @@ cross_branch_2a_5: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
-                y = "foo";
+                x = "foo";
                 if (b)
-                    console.log(y);
-                y = "bar";
+                    console.log(x);
+                x = "bar";
             }
-            console.log(y);
+            console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -1427,13 +1695,13 @@ cross_branch_2a_10: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
-            y = "foo";
+            var x, x;
+            x = "foo";
             if (a) {
                 if (b)
-                    console.log(y);
-                y = "bar";
-                console.log(y);
+                    console.log(x);
+                x = "bar";
+                console.log(x);
             }
         }
         a = 0, b = 0;
@@ -1590,13 +1858,13 @@ cross_branch_2a_13: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
-            y = "foo";
+            var x, x;
+            x = "foo";
             if (a) {
-                console.log(y);
+                console.log(x);
                 if (b) {
-                    y = "bar";
-                    console.log(y);
+                    x = "bar";
+                    console.log(x);
                 }
             }
         }
@@ -1644,13 +1912,13 @@ cross_branch_2a_14: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
-            y = "foo";
+            var x, x;
+            x = "foo";
             if (a) {
-                console.log(y);
-                y = "bar";
+                console.log(x);
+                x = "bar";
                 if (b)
-                    console.log(y);
+                    console.log(x);
             }
         }
         a = 0, b = 0;
@@ -1753,13 +2021,13 @@ cross_branch_2a_16: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
-            y = "foo";
-            console.log(y);
+            var x, x;
+            x = "foo";
+            console.log(x);
             if (a) {
-                y = "bar";
+                x = "bar";
                 if (b)
-                    console.log(y);
+                    console.log(x);
             }
         }
         a = 0, b = 0;
@@ -1807,13 +2075,13 @@ cross_branch_2b_1: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a)
-                y = "foo";
+                x = "foo";
             if (b)
-                console.log(y);
-            y = "bar";
-            console.log(y);
+                console.log(x);
+            x = "bar";
+            console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -1918,13 +2186,13 @@ cross_branch_2b_3: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a)
-                y = "foo";
+                x = "foo";
             if (b) {
-                console.log(y);
-                y = "bar";
-                console.log(y);
+                console.log(x);
+                x = "bar";
+                console.log(x);
             }
         }
         a = 0, b = 0;
@@ -2028,13 +2296,13 @@ cross_branch_2b_5: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a)
-                y = "foo";
-            console.log(y);
+                x = "foo";
+            console.log(x);
             if (b) {
-                y = "bar";
-                console.log(y);
+                x = "bar";
+                console.log(x);
             }
         }
         a = 0, b = 0;
@@ -2141,14 +2409,14 @@ cross_branch_2b_7: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
-                y = "foo";
-                console.log(y);
+                x = "foo";
+                console.log(x);
             }
             if (b) {
-                y = "bar";
-                console.log(y);
+                x = "bar";
+                console.log(x);
             }
         }
         a = 0, b = 0;
@@ -2195,13 +2463,13 @@ cross_branch_2b_8: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a)
-                y = "foo";
-            console.log(y);
-            y = "bar";
+                x = "foo";
+            console.log(x);
+            x = "bar";
             if (b)
-                console.log(y);
+                console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -2250,14 +2518,14 @@ cross_branch_2b_9: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
-                y = "foo";
-                console.log(y);
+                x = "foo";
+                console.log(x);
             }
-            y = "bar";
+            x = "bar";
             if (b)
-                console.log(y);
+                console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -2304,14 +2572,14 @@ cross_branch_2b_10: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
+            var x, x;
             if (a) {
-                y = "foo";
-                console.log(y);
-                y = "bar";
+                x = "foo";
+                console.log(x);
+                x = "bar";
             }
             if (b)
-                console.log(y);
+                console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -2412,13 +2680,13 @@ cross_branch_2b_12: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
-            y = "foo";
+            var x, x;
+            x = "foo";
             if (a)
-                console.log(y);
+                console.log(x);
             if (b) {
-                y = "bar";
-                console.log(y);
+                x = "bar";
+                console.log(x);
             }
         }
         a = 0, b = 0;
@@ -2465,13 +2733,13 @@ cross_branch_2b_13: {
     expect: {
         var a, b;
         function f() {
-            var y, y;
-            y = "foo";
+            var x, x;
+            x = "foo";
             if (a)
-                console.log(y);
-            y = "bar";
+                console.log(x);
+            x = "bar";
             if (b)
-                console.log(y);
+                console.log(x);
         }
         a = 0, b = 0;
         f();
@@ -2620,11 +2888,11 @@ issue_4126_1: {
             try {
                 console.log("PASS");
             } catch (e) {
-                var c = a;
+                var b = a;
             } finally {
-                var c = c;
+                var a = b;
             }
-            console.log(c);
+            console.log(a);
         }
         f("FAIL");
     }
@@ -2816,11 +3084,11 @@ conditional_write: {
         console.log(b);
     }
     expect: {
-        var b = "FAIL", b;
+        var a = "FAIL", a;
         if (console)
-            b = "PASS";
-        b = [b, 42].join();
-        console.log(b);
+            a = "PASS";
+        a = [a, 42].join();
+        console.log(a);
     }
     expect_stdout: "PASS,42"
 }
@@ -2994,13 +3262,13 @@ issue_4168_use_strict: {
     expect: {
         "use strict";
         var o = {
-            f: function(d, e, f) {
-                var d = d.d;
-                var e = e.e;
-                var f = f.f;
+            f: function(a, b, c) {
+                var a = a.d;
+                var b = b.e;
+                var c = c.f;
                 this.g(arguments);
-                if (d)
-                    console.log(e, f);
+                if (a)
+                    console.log(b, c);
             },
             g: function(args) {
                 console.log(args[0], args[1], args[2]);
@@ -3228,10 +3496,10 @@ issue_4653: {
         f(a++ + (b = b), b |= console.log(a));
     }
     expect: {
-        var b = 1;
+        var b, a = 1;
         (function(c, d) {
             c || console.log(d);
-        })(+b + (b = void 0), b |= console.log(2));
+        })(+a + (b = b), b |= console.log(2));
     }
     expect_stdout: [
         "2",
@@ -3377,3 +3645,90 @@ issue_4956_2: {
     }
     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"
+}
+
+issue_5420: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        do {
+            var a = "FAIL 1";
+            a && a.p;
+            a = "FAIL 2";
+            try {
+                continue;
+            } catch (e) {}
+            var b = "FAIL 3";
+        } while (console.log(b || "PASS"));
+    }
+    expect: {
+        do {
+            var a = "FAIL 1";
+            a && a.p;
+            a = "FAIL 2";
+            try {
+                continue;
+            } catch (e) {}
+            var b = "FAIL 3";
+        } while (console.log(b || "PASS"));
+    }
+    expect_stdout: "PASS"
+}

test/compress/negate-iife.js

@@ -122,13 +122,41 @@ negate_iife_4: {
         sequences: true,
     }
     input: {
-        (function(){ return t })() ? console.log(true) : console.log(false);
-        (function(){
+        (function() {
+            return t;
+        })() ? console.log(true) : console.log(false);
+        (function() {
             console.log("something");
         })();
     }
     expect: {
-        !function(){ return t }() ? console.log(false) : console.log(true), function(){
+        !function() {
+            return t;
+        }() ? console.log(false) : console.log(true), !function() {
+            console.log("something");
+        }();
+    }
+}
+
+negate_iife_4_drop_side_effect_free: {
+    options = {
+        conditionals: true,
+        negate_iife: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        (function() {
+            return t;
+        })() ? console.log(true) : console.log(false);
+        (function() {
+            console.log("something");
+        })();
+    }
+    expect: {
+        !function() {
+            return t;
+        }() ? console.log(false) : console.log(true), function() {
             console.log("something");
         }();
     }
@@ -176,17 +204,49 @@ negate_iife_5: {
         sequences: true,
     }
     input: {
-        if ((function(){ return t })()) {
+        if (function() {
+            return t;
+        }()) {
             foo(true);
         } else {
             bar(false);
         }
-        (function(){
+        (function() {
             console.log("something");
         })();
     }
     expect: {
-        !function(){ return t }() ? bar(false) : foo(true), function(){
+        !function() {
+            return t;
+        }() ? bar(false) : foo(true), !function() {
+            console.log("something");
+        }();
+    }
+}
+
+negate_iife_5_drop_side_effect_free: {
+    options = {
+        conditionals: true,
+        negate_iife: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        if (function() {
+            return t;
+        }()) {
+            foo(true);
+        } else {
+            bar(false);
+        }
+        (function() {
+            console.log("something");
+        })();
+    }
+    expect: {
+        !function() {
+            return t;
+        }() ? bar(false) : foo(true), function() {
             console.log("something");
         }();
     }
@@ -389,6 +449,7 @@ issue_1288_side_effects: {
     options = {
         conditionals: true,
         negate_iife: true,
+        sequences: true,
         side_effects: true,
     }
     input: {
@@ -409,10 +470,10 @@ issue_1288_side_effects: {
             })(0);
     }
     expect: {
-        w;
+        w,
         x || function() {
             x = {};
-        }();
+        }(),
         y;
     }
 }

test/compress/nullish.js

@@ -262,6 +262,30 @@ de_morgan_2e: {
     node_version: ">=14"
 }
 
+inline_binary_nullish: {
+    options = {
+        inline: true,
+    }
+    input: {
+        (function() {
+            while (console.log("foo"));
+        })() ?? (function() {
+            while (console.log("bar"));
+        })();
+    }
+    expect: {
+        if (null == function() {
+            while (console.log("foo"));
+        }())
+            while (console.log("bar"));
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    node_version: ">=14"
+}
+
 issue_4679: {
     options = {
         comparisons: true,
@@ -280,3 +304,42 @@ issue_4679: {
     expect_stdout: "PASS"
     node_version: ">=14"
 }
+
+issue_5266: {
+    options = {
+        inline: true,
+    }
+    input: {
+        [
+            42,
+            null,
+            false,
+            void 0,
+            "FAIL",
+        ].forEach(function (a) {
+            a ?? function() {
+                while (console.log(a));
+            }();
+        });
+    }
+    expect: {
+        [
+            42,
+            null,
+            false,
+            void 0,
+            "FAIL",
+        ].forEach(function (a) {
+            if (null == a) {
+                while (console.log(a));
+                return;
+            } else
+                return;
+        });
+    }
+    expect_stdout: [
+        "null",
+        "undefined",
+    ]
+    node_version: ">=14"
+}

test/compress/numbers.js

@@ -842,9 +842,9 @@ unary_binary_parentheses: {
         v.forEach(function(x) {
             v.forEach(function(y) {
                 console.log(
-                    +x*y,
-                    +x/y,
-                    +x%y,
+                    x*y,
+                    x/y,
+                    x%y,
                     -x*y,
                     -x/y,
                     -x%y
@@ -1397,7 +1397,7 @@ issue_3695: {
     }
     expect: {
         var a = [];
-        console.log(+(a * (a[0] = false)));
+        console.log(a * (a[0] = false));
     }
     expect_stdout: "NaN"
 }

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

@@ -361,7 +361,9 @@ issue_4906: {
         } while (console.log("PASS"));
     }
     expect: {
-        do {} while (console.log("PASS"));
+        do {
+            var a = a?.[42];
+        } while (console.log("PASS"));
     }
     expect_stdout: "PASS"
     node_version: ">=14"
@@ -434,7 +436,7 @@ issue_5039: {
         console.log("PASS");
     }
     expect: {
-        (function f() {});
+        var a = a?.[function f() {}];
         console.log("PASS");
     }
     expect_stdout: "PASS"
@@ -455,14 +457,163 @@ issue_5091: {
         console.log(f("FAIL 1") || "PASS");
     }
     expect: {
-        function f(b) {
-            var b = b.p;
+        function f(a) {
+            var a = a.p;
             var c;
-            b?.[c = "FAIL 2"];
-            return b || c;
+            a?.[c = "FAIL 2"];
+            return a || c;
         }
         console.log(f("FAIL 1") || "PASS");
     }
     expect_stdout: "PASS"
     node_version: ">=14"
 }
+
+issue_5292_dot: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            }
+        };
+        o?.p;
+    }
+    expect: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            }
+        };
+        o?.p;
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+issue_5292_dot_pure_getters: {
+    options = {
+        pure_getters: true,
+        side_effects: true,
+    }
+    input: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            }
+        };
+        o?.p;
+    }
+    expect: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            }
+        };
+    }
+}
+
+issue_5292_dot_pure_getters_strict: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            }
+        };
+        o?.p;
+    }
+    expect: {
+        var o = {
+            get p() {
+                console.log("PASS");
+            }
+        };
+        o?.p;
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+issue_5292_sub: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        var o = {
+            get p() {
+                console.log("foo");
+            }
+        };
+        o?.[console.log("bar"), "p"];
+    }
+    expect: {
+        var o = {
+            get p() {
+                console.log("foo");
+            }
+        };
+        o?.[console.log("bar"), "p"];
+    }
+    expect_stdout: [
+        "bar",
+        "foo",
+    ]
+    node_version: ">=14"
+}
+
+issue_5292_sub_pure_getters: {
+    options = {
+        pure_getters: true,
+        side_effects: true,
+    }
+    input: {
+        var o = {
+            get p() {
+                console.log("foo");
+            }
+        };
+        o?.[console.log("bar"), "p"];
+    }
+    expect: {
+        var o = {
+            get p() {
+                console.log("foo");
+            }
+        };
+        console.log("bar");
+    }
+}
+
+issue_5292_sub_pure_getters_strict: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        var o = {
+            get p() {
+                console.log("foo");
+            }
+        };
+        o?.[console.log("bar"), "p"];
+    }
+    expect: {
+        var o = {
+            get p() {
+                console.log("foo");
+            }
+        };
+        o?.[console.log("bar"), "p"];
+    }
+    expect_stdout: [
+        "bar",
+        "foo",
+    ]
+    node_version: ">=14"
+}

test/compress/preserve_line.js

@@ -97,10 +97,10 @@ return_5: {
     }
     expect_exact: [
         "_is_selected=function(tags,slug){",
-        "var ref",
+        "var ref;",
         "",
         "",
-        ";return null!=(ref=_.find(tags,{slug:slug}))?ref.selected:void 0};",
+        "return null!=(ref=_.find(tags,{slug:slug}))?ref.selected:void 0};",
     ]
 }
 
@@ -146,10 +146,10 @@ return_7: {
     }
     expect_exact: [
         "_is_selected=function(e,l){",
-        "var n",
+        "var n;",
         "",
         "",
-        ";return null!=(n=_.find(e,{slug:l}))?n.selected:void 0};",
+        "return null!=(n=_.find(e,{slug:l}))?n.selected:void 0};",
     ]
 }
 

test/compress/properties.js

@@ -1510,3 +1510,71 @@ issue_5093_quote_style: {
     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

@@ -1289,6 +1289,7 @@ issue_2878: {
         collapse_vars: true,
         pure_getters: true,
         sequences: true,
+        side_effects: true,
     }
     input: {
         var c = 0;
@@ -1363,9 +1364,8 @@ issue_3490_1: {
     }
     expect: {
         var b = 42, c = "FAIL";
-        if (function() {
-            var a;
-        }(), c = "PASS", b) while ("" == typeof d);
+        var a;
+        if (c = "PASS", b) while ("" == typeof d);
         console.log(c, b);
     }
     expect_stdout: "PASS 42"
@@ -1640,6 +1640,26 @@ 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",

test/compress/reduce_vars.js

@@ -6,6 +6,7 @@ reduce_vars: {
             C: 0,
         },
         inline: true,
+        passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
         toplevel: true,
@@ -41,10 +42,8 @@ reduce_vars: {
     }
     expect: {
         var A = 1;
-        (function() {
-            console.log(-3);
-            console.log(A - 5);
-        })();
+        console.log(-3);
+        console.log(A - 5);
         (function f1() {
             var a = 2;
             console.log(a - 5);
@@ -905,7 +904,7 @@ use_before_var: {
     }
     expect: {
         function f(){
-            console.log(void 0);
+            console.log(t);
             var t = 1;
         }
     }
@@ -981,7 +980,7 @@ inner_var_for_1: {
     expect: {
         function f() {
             var a = 1;
-            x(1, void 0, d);
+            x(1, b, d);
             for (var b = 2, c = 3; x(1, 2, 3, d); x(1, 2, 3, d)) {
                 var d = 4, e = 5;
                 x(1, 2, 3, d, e);
@@ -6671,6 +6670,7 @@ issues_3267_1: {
         dead_code: true,
         evaluate: true,
         inline: true,
+        negate_iife: true,
         reduce_vars: true,
         sequences: true,
         side_effects: true,
@@ -6688,7 +6688,7 @@ issues_3267_1: {
         });
     }
     expect: {
-        !function(i) {
+        !function(x) {
             if (Object())
                 return console.log("PASS");
             throw "FAIL";
@@ -6705,6 +6705,7 @@ issues_3267_2: {
         evaluate: true,
         inline: true,
         keep_fargs: false,
+        negate_iife: true,
         passes: 2,
         reduce_vars: true,
         sequences: true,
@@ -7320,6 +7321,64 @@ 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,
@@ -7435,6 +7494,7 @@ issue_4030: {
         collapse_vars: true,
         evaluate: true,
         reduce_vars: true,
+        side_effects: true,
         toplevel: true,
         unused: true,
     }
@@ -7772,3 +7832,67 @@ issue_5055_2: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5324: {
+    options = {
+        inline: true,
+        merge_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        A = 0;
+        do {
+            var a, b = A;
+            for (a in b)
+                var c = b;
+        } while (function() {
+            var d;
+            console.log(d *= A);
+        }());
+    }
+    expect: {
+        A = 0;
+        do {
+            var a, b = A;
+            for (a in b);
+        } while (b = void 0, void console.log(b *= A));
+    }
+    expect_stdout: "NaN"
+}
+
+issue_5434: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a) {
+            for (var i = 0; i < 2; i++) {
+                var b = "FAIL";
+                f && f();
+                a = b;
+                var f = function() {
+                    b = "PASS";
+                };
+            }
+            return a;
+        }());
+    }
+    expect: {
+        console.log(function(a) {
+            for (var i = 0; i < 2; i++) {
+                var b = "FAIL";
+                f && f();
+                a = b;
+                var f = function() {
+                    b = "PASS";
+                };
+            }
+            return a;
+        }());
+    }
+    expect_stdout: "PASS"
+}

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: {
@@ -270,7 +270,7 @@ retain_destructured_object_1: {
         "1 PASS",
         "2 42",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 retain_destructured_object_2: {
@@ -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: {
@@ -344,11 +344,12 @@ 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: {
     options = {
+        keep_fargs: false,
         unused: true,
     }
     input: {
@@ -359,10 +360,10 @@ retain_funarg_destructured_object_2: {
     expect: {
         console.log(function({ p: a, ... b }) {
             return b;
-        }({ p: "FAIL" }).p || "PASS");
+        }({}).p || "PASS");
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 drop_unused_call_args_1: {
@@ -436,9 +437,9 @@ merge_funarg: {
         })();
     }
     expect: {
-        (function(...b) {
-            var b = b.length;
-            console.log(b);
+        (function(...a) {
+            var a = a.length;
+            console.log(a);
         })();
     }
     expect_stdout: "0"
@@ -456,9 +457,9 @@ merge_funarg_destructured_array: {
         })([]);
     }
     expect: {
-        (function([ ...b ]) {
-            var b = b.length;
-            console.log(b);
+        (function([ ...a ]) {
+            var a = a.length;
+            console.log(a);
         })([]);
     }
     expect_stdout: "0"
@@ -476,13 +477,13 @@ merge_funarg_destructured_object: {
         })([ "PASS" ]);
     }
     expect: {
-        (function({ ...b }) {
-            var b = b[0];
-            console.log(b);
+        (function({ ...a }) {
+            var a = a[0];
+            console.log(a);
         })([ "PASS" ]);
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_arguments: {
@@ -866,9 +867,9 @@ issue_4575: {
     }
     expect: {
         (function(a) {
-            (function a(...d) {
+            (function(d) {
                 console.log(d.length);
-            })();
+            })([]);
         })();
     }
     expect_stdout: "0"
@@ -992,7 +993,7 @@ issue_5089_1: {
         console.log(o.p);
     }
     expect_stdout: "undefined"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_5089_2: {
@@ -1019,7 +1020,7 @@ issue_5089_2: {
         console.log(o.p);
     }
     expect_stdout: "undefined"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_5100_1: {
@@ -1044,17 +1045,19 @@ issue_5100_1: {
     }
     expect: {
         var a;
-        [ {
+        ({
             p: {},
             ...a
-        } ] = [ {
-            p: [ a = 42["q"] ],
+        } = [ {
+            p: {
+                q: a,
+            } = 42,
             r: "PASS",
-        } ];
+        } ][0]);
         console.log(a.r);
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_5100_2: {
@@ -1077,20 +1080,23 @@ issue_5100_2: {
     }
     expect: {
         var a;
-        [ {
+        ({
             p: {},
             ...a
-        } ] = [ {
-            p: [ console.log("PASS"), a = 42["q"] ],
-        } ];
+        } = [ {
+            p: (console.log("PASS"), {
+                q: a,
+            } = 42),
+        } ][0]);
     }
     expect_stdout: "PASS"
-    node_version: ">=10"
+    node_version: ">=10.22.0"
 }
 
 issue_5108: {
     options = {
         evaluate: true,
+        keep_fargs: false,
         reduce_vars: true,
         rests: true,
         unsafe: true,
@@ -1102,10 +1108,258 @@ issue_5108: {
         }([ "PASS", "FAIL" ]));
     }
     expect: {
-        console.log(function([]) {
-            return "PASS";
-        }([ "PASS", "FAIL" ]));
+        console.log("PASS");
     }
     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"
+}
+
+issue_5246_1: {
+    options = {
+        keep_fargs: false,
+        reduce_vars: true,
+        rests: true,
+        unused: true,
+    }
+    input: {
+        console.log(typeof function([ , ...a ]) {
+            return this && a;
+        }([ , function(){} ])[0]);
+    }
+    expect: {
+        console.log(typeof function() {
+            return this && [ function(){} ];
+        }()[0]);
+    }
+    expect_stdout: "function"
+    node_version: ">=6"
+}
+
+issue_5246_2: {
+    options = {
+        keep_fargs: false,
+        reduce_vars: true,
+        rests: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        A = [ , "PASS", "FAIL" ];
+        var  [ , ...a ] = [ ... A ];
+        console.log(a[0]);
+    }
+    expect: {
+        A = [ , "PASS", "FAIL" ];
+        var  [ , ...a ] = [ ... A ];
+        console.log(a[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5246_3: {
+    options = {
+        keep_fargs: false,
+        unused: true,
+    }
+    input: {
+        (function f(...[ [ a ] ]) {
+            console.log(a);
+        })([ "PASS" ]);
+    }
+    expect: {
+        (function(...[ a ]) {
+            console.log(a);
+        })([ "PASS" ][0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5360: {
+    options = {
+        keep_fargs: false,
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        var a;
+        console.log(function({ p: {}, ...b }) {
+            return b.q;
+        }({
+            p: ~a && ([ a ] = []),
+            q: "PASS",
+        }));
+    }
+    expect: {
+        var a;
+        console.log(function({ p: {}, ...b }) {
+            return b.q;
+        }({
+            p: ~a && ([ a ] = []),
+            q: "PASS",
+        }));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8.3.0"
+}
+
+issue_5370: {
+    options = {
+        dead_code: true,
+        ie: true,
+        unused: true,
+    }
+    input: {
+        console.log(function arguments(...a) {
+            return arguments;
+            try {} catch (e) {
+                var arguments;
+            }
+        }());
+    }
+    expect: {
+        console.log(function arguments(...a) {
+            return arguments;
+            var arguments;
+        }());
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+issue_5391: {
+    options = {
+        evaluate: true,
+        keep_fargs: false,
+        objects: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b = function f({
+            p: {},
+            ...c
+        }) {
+            while (c.q);
+        }({
+            p: {
+                r: a++,
+                r: 0,
+            }
+        });
+        console.log(a);
+    }
+    expect: {
+        (function({
+            p: {},
+            ...c
+        }) {
+            while (c.q);
+        })({
+            p: 0,
+        });
+        console.log(NaN);
+    }
+    expect_stdout: "NaN"
+    node_version: ">=8.3.0"
+}

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/sequences.js

@@ -289,8 +289,34 @@ iife: {
         typeof function g() {}();
     }
     expect: {
-        x = 42, function a() {}(), function b() {}(), function c() {}(),
-        function d() {}(), function e() {}(), function f() {}(), function g() {}();
+        x = 42,
+        function a() {}(),
+        !function b() {}(),
+        ~function c() {}(),
+        +function d() {}(),
+        -function e() {}(),
+        void function f() {}(),
+        typeof function g() {}();
+    }
+}
+
+iife_drop_side_effect_free: {
+    options = {
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        x = 42;
+        (function a() {})();
+        !function b() {}();
+        ~function c() {}();
+        +function d() {}();
+        -function e() {}();
+        void function f() {}();
+        typeof function g() {}();
+    }
+    expect: {
+        x = 42;
     }
 }
 
@@ -774,7 +800,7 @@ side_effects_cascade_3: {
     }
     expect: {
         function f(a, b) {
-            (b += a) || (b = a) || (b -= a, b ^= a),
+            (b += a) || (b = a) || (b = b - a ^ a),
             a--;
         }
     }
@@ -910,9 +936,7 @@ hoist_decl: {
         var d;
     }
     expect: {
-        var a;
-        w();
-        var b = x(), c, d;
+        var a, b = (w(), x()), c, d;
         for (y(); 0;) z();
     }
 }
@@ -1047,11 +1071,102 @@ call: {
         b.c = function() {
             console.log(this === b ? "bar" : "baz");
         },
+        a,
         b(),
+        a,
         b.c(),
         (a, b.c)(),
+        a,
         b["c"](),
         (a, b["c"])(),
+        a,
+        function() {
+            console.log(this === a);
+        }(),
+        a,
+        new b(),
+        a,
+        new b.c(),
+        a,
+        new b.c(),
+        a,
+        new b["c"](),
+        a,
+        new b["c"](),
+        a,
+        new function() {
+            console.log(this === a);
+        }(),
+        console.log((a, typeof b.c)),
+        console.log((a, typeof b["c"]));
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "baz",
+        "bar",
+        "baz",
+        "true",
+        "foo",
+        "baz",
+        "baz",
+        "baz",
+        "baz",
+        "false",
+        "function",
+        "function",
+    ]
+}
+
+call_drop_side_effect_free: {
+    options = {
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        var a = function() {
+            return this;
+        }();
+        function b() {
+            console.log("foo");
+        }
+        b.c = function() {
+            console.log(this === b ? "bar" : "baz");
+        };
+        (a, b)();
+        (a, b).c();
+        (a, b.c)();
+        (a, b)["c"]();
+        (a, b["c"])();
+        (a, function() {
+            console.log(this === a);
+        })();
+        new (a, b)();
+        new (a, b).c();
+        new (a, b.c)();
+        new (a, b)["c"]();
+        new (a, b["c"])();
+        new (a, function() {
+            console.log(this === a);
+        })();
+        console.log(typeof (a, b).c);
+        console.log(typeof (a, b)["c"]);
+    }
+    expect: {
+        var a = function() {
+            return this;
+        }();
+        function b() {
+            console.log("foo");
+        }
+        b.c = function() {
+            console.log(this === b ? "bar" : "baz");
+        },
+        b(),
+        b.c(),
+        (0, b.c)(),
+        b["c"](),
+        (0, b["c"])(),
         function() {
             console.log(this === a);
         }(),
@@ -1063,8 +1178,8 @@ call: {
         new function() {
             console.log(this === a);
         }(),
-        console.log((a, typeof b.c)),
-        console.log((a, typeof b["c"]));
+        console.log(typeof b.c),
+        console.log(typeof b["c"]);
     }
     expect_stdout: [
         "foo",
@@ -1099,6 +1214,26 @@ missing_link: {
     expect: {
         var a = 100;
         a,
+        a++ + (0, 1),
+        console.log(a);
+    }
+}
+
+missing_link_drop_side_effect_free: {
+    options = {
+        conditionals: true,
+        evaluate: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 100;
+        a;
+        a++ + (0 ? 2 : 1);
+        console.log(a);
+    }
+    expect: {
+        var a = 100;
         a++,
         console.log(a);
     }
@@ -1162,10 +1297,8 @@ issue_3490_1: {
     }
     expect: {
         var b = 42, c = "FAIL";
-        if (function() {
-            var a;
-            a && a.p;
-        }(), c = "PASS", b) while ("" == typeof d);
+        var a;
+        if (a && a.p, c = "PASS", b) while ("" == typeof d);
         console.log(c, b);
     }
     expect_stdout: "PASS 42"
@@ -1195,9 +1328,8 @@ issue_3490_2: {
     }
     expect: {
         var b = 42, c = "FAIL";
-        for (function() {
-            var a;
-        }(), c = "PASS", b; "" == typeof d;);
+        var a;
+        for (c = "PASS"; "" == typeof d;);
         console.log(c, b);
     }
     expect_stdout: "PASS 42"

test/compress/side_effects.js

@@ -617,7 +617,7 @@ issue_4730_2: {
     }
     expect: {
         var a;
-        !console.log("PASS") || a && a[a.p];
+        console.log("PASS") && a && a[a.p];
     }
     expect_stdout: "PASS"
 }

test/compress/spreads.js

@@ -147,7 +147,7 @@ dont_inline: {
     node_version: ">=6"
 }
 
-do_inline: {
+do_inline_1: {
     options = {
         inline: true,
         spreads: true,
@@ -164,6 +164,46 @@ do_inline: {
     node_version: ">=6"
 }
 
+do_inline_2: {
+    options = {
+        inline: true,
+        side_effects: true,
+    }
+    input: {
+        (function() {
+            (function() {
+                console.log("PASS");
+            })(..."");
+        })();
+    }
+    expect: {
+        [] = [ ..."" ],
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+do_inline_3: {
+    options = {
+        if_return: true,
+        inline: true,
+    }
+    input: {
+        (function() {
+            (function() {
+                while (console.log("PASS"));
+            })(..."");
+        })();
+    }
+    expect: {
+        var [] = [ ..."" ];
+        while (console.log("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 drop_empty_call_1: {
     options = {
         side_effects: true,
@@ -201,7 +241,29 @@ drop_empty_call_2: {
     node_version: ">=6"
 }
 
-convert_hole: {
+convert_hole_array: {
+    options = {
+        spreads: true,
+    }
+    input: {
+        [ ...[ "PASS", , 42 ] ].forEach(function(a) {
+            console.log(a);
+        });
+    }
+    expect: {
+        [ "PASS", void 0, 42 ].forEach(function(a) {
+            console.log(a);
+        });
+    }
+    expect_stdout: [
+        "PASS",
+        "undefined",
+        "42",
+    ]
+    node_version: ">=6"
+}
+
+convert_hole_call: {
     options = {
         spreads: true,
     }
@@ -341,7 +403,7 @@ convert_setter: {
             console.log(k, o[k]);
     }
     expect_stdout: "PASS undefined"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_getter_1: {
@@ -370,7 +432,7 @@ keep_getter_1: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_getter_2: {
@@ -399,7 +461,7 @@ keep_getter_2: {
         "foo",
         "bar",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_getter_3: {
@@ -429,7 +491,7 @@ keep_getter_3: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_getter_4: {
@@ -460,7 +522,7 @@ keep_getter_4: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 keep_accessor: {
@@ -508,7 +570,7 @@ keep_accessor: {
         "q undefined",
         "r null",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_key_order_1: {
@@ -538,7 +600,7 @@ object_key_order_1: {
         "a 3",
         "b 2",
     ]
-    node_version: ">=8 <=10"
+    node_version: ">=8.3.0 <=10"
 }
 
 object_key_order_2: {
@@ -568,7 +630,7 @@ object_key_order_2: {
         "a 3",
         "b 2",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_key_order_3: {
@@ -598,7 +660,7 @@ object_key_order_3: {
         "a 3",
         "b 2",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_key_order_4: {
@@ -628,7 +690,7 @@ object_key_order_4: {
         "a 3",
         "b 2",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_spread_array: {
@@ -654,7 +716,7 @@ object_spread_array: {
         "0 foo",
         "1 bar",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 object_spread_string: {
@@ -681,7 +743,7 @@ object_spread_string: {
         "1 o",
         "2 o",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 unused_var_side_effects: {
@@ -711,7 +773,7 @@ unused_var_side_effects: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 unsafe_join_1: {
@@ -793,7 +855,7 @@ issue_4329: {
         }[0]);
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4331: {
@@ -871,7 +933,7 @@ issue_4345: {
         }[42]);
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4361: {
@@ -901,7 +963,7 @@ issue_4361: {
         "foo",
         "undefined",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4363: {
@@ -922,7 +984,7 @@ issue_4363: {
         });
     }
     expect_stdout: "PASS"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4556: {
@@ -994,7 +1056,7 @@ issue_4849: {
         }()));
     }
     expect_stdout: "object"
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4882_1: {
@@ -1026,7 +1088,7 @@ issue_4882_1: {
         "PASS",
         "undefined",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4882_2: {
@@ -1052,7 +1114,7 @@ issue_4882_2: {
         "42",
         "PASS",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_4882_3: {
@@ -1082,7 +1144,7 @@ issue_4882_3: {
         "PASS",
         "42",
     ]
-    node_version: ">=8"
+    node_version: ">=8.3.0"
 }
 
 issue_5006: {
@@ -1104,3 +1166,31 @@ issue_5006: {
     expect_stdout: "PASS"
     node_version: ">=6"
 }
+
+issue_5382: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        ({
+            f() {
+                ({ ...this });
+            },
+            get p() {
+                console.log("PASS");
+            },
+        }).f();
+    }
+    expect: {
+        ({
+            f() {
+                ({ ...this });
+            },
+            get p() {
+                console.log("PASS");
+            },
+        }).f();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8.3.0"
+}

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: {
@@ -357,13 +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"
@@ -434,3 +534,238 @@ issue_4931: {
     ]
     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/typeof.js

@@ -307,7 +307,7 @@ typeof_defined_1: {
     }
     expect: {
         "undefined" == typeof A && A;
-        "undefined" != typeof A || A;
+        "undefined" == typeof A && A;
     }
 }
 
@@ -324,7 +324,7 @@ typeof_defined_2: {
     }
     expect: {
         "function" != typeof A && A;
-        "function" == typeof A || A;
+        "function" != typeof A && A;
     }
 }
 
@@ -355,16 +355,19 @@ typeof_defined_3: {
         "undefined" == typeof A && "undefined" == typeof B && (A, B);
         "undefined" == typeof A && "undefined" != typeof B && A;
         "undefined" != typeof A && "undefined" == typeof B && B;
+        // dropped
         "undefined" == typeof A && "undefined" == typeof B || (A, B);
         "undefined" == typeof A && "undefined" != typeof B || (A, B);
         "undefined" != typeof A && "undefined" == typeof B || (A, B);
         "undefined" != typeof A && "undefined" != typeof B || (A, B);
-        "undefined" == typeof A || "undefined" == typeof B && B;
-        "undefined" != typeof A || "undefined" == typeof B && (A, B);
-        "undefined" != typeof A || "undefined" != typeof B && A;
-        "undefined" == typeof A || "undefined" != typeof B || B;
-        "undefined" != typeof A || "undefined" == typeof B || A;
-        "undefined" != typeof A || "undefined" != typeof B || (A, B);
+        "undefined" != typeof A && "undefined" == typeof B && B;
+        // dropped
+        "undefined" == typeof A && "undefined" == typeof B && (A, B);
+        "undefined" == typeof A && "undefined" != typeof B && A;
+        // dropped
+        "undefined" != typeof A && "undefined" == typeof B && B;
+        "undefined" == typeof A && "undefined" != typeof B && A;
+        "undefined" == typeof A && "undefined" == typeof B && (A, B);
     }
 }
 
@@ -392,6 +395,7 @@ typeof_defined_4: {
         "object" != typeof A || "object" != typeof B || (A, B);
     }
     expect: {
+        // dropped
         "object" == typeof A && "object" != typeof B && B;
         "object" != typeof A && "object" == typeof B && A;
         "object" != typeof A && "object" != typeof B && (A, B);
@@ -399,12 +403,14 @@ typeof_defined_4: {
         "object" == typeof A && "object" != typeof B || (A, B);
         "object" != typeof A && "object" == typeof B || (A, B);
         "object" != typeof A && "object" != typeof B || (A, B);
-        "object" == typeof A || "object" == typeof B && A;
-        "object" == typeof A || "object" != typeof B && (A, B);
-        "object" != typeof A || "object" != typeof B && B;
-        "object" == typeof A || "object" == typeof B || (A, B);
-        "object" == typeof A || "object" != typeof B || A;
-        "object" != typeof A || "object" == typeof B || B;
+        "object" != typeof A && "object" == typeof B && A;
+        "object" != typeof A && "object" != typeof B && (A, B);
+        // dropped
+        "object" == typeof A && "object" != typeof B && B;
+        "object" != typeof A && "object" != typeof B && (A, B);
+        "object" != typeof A && "object" == typeof B && A;
+        "object" == typeof A && "object" != typeof B && B;
+        // dropped
     }
 }
 
@@ -436,6 +442,245 @@ emberjs_global: {
     expect_stdout: Error("PASS")
 }
 
+reassign: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        passes: 2,
+        typeofs: true,
+    }
+    input: {
+        A = console;
+        if ("undefined" == typeof A)
+            console.log("FAIL 1");
+        else {
+            A = void 0;
+            while (console.log(void 0 === A ? "PASS" : "FAIL 2"));
+        }
+    }
+    expect: {
+        A = console;
+        if ("undefined" == typeof A)
+            console.log("FAIL 1");
+        else {
+            A = void 0;
+            while (console.log(void 0 === A ? "PASS" : "FAIL 2"));
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+reassign_call: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        passes: 2,
+        typeofs: true,
+    }
+    input: {
+        A = console;
+        function f() {
+            A = void 0;
+        }
+        if ("undefined" == typeof A)
+            console.log("FAIL 1");
+        else {
+            f();
+            while (console.log(void 0 === A ? "PASS" : "FAIL 2"));
+        }
+    }
+    expect: {
+        A = console;
+        function f() {
+            A = void 0;
+        }
+        if ("undefined" == typeof A)
+            console.log("FAIL 1");
+        else {
+            f();
+            while (console.log(void 0 === A ? "PASS" : "FAIL 2"));
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+reassign_conditional: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        passes: 2,
+        typeofs: true,
+    }
+    input: {
+        A = console;
+        if ("undefined" == typeof A)
+            console.log("FAIL 1");
+        else {
+            A &&= void 0;
+            while (console.log(void 0 === A ? "PASS" : "FAIL 2"));
+        }
+    }
+    expect: {
+        A = console;
+        if ("undefined" == typeof A)
+            console.log("FAIL 1");
+        else {
+            A &&= void 0;
+            while (console.log(void 0 === A ? "PASS" : "FAIL 2"));
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=15"
+}
+
+reassign_do: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        if_return: true,
+        passes: 2,
+        reduce_vars: true,
+        typeofs: true,
+    }
+    input: {
+        A = console;
+        (function() {
+            if ("undefined" == typeof A)
+                return;
+            var a = A, i = 2;
+            do {
+                console.log(void 0 === A, void 0 === a);
+                A = void 0;
+            } while (--i);
+        })();
+    }
+    expect: {
+        A = console;
+        (function() {
+            if ("undefined" != typeof A) {
+                var a = A, i = 2;
+                do {
+                    console.log(void 0 === A, (a, false));
+                    A = void 0;
+                } while (--i);
+            }
+        })();
+    }
+    expect_stdout: [
+        "false false",
+        "true false",
+    ]
+}
+
+reassign_for: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        passes: 2,
+        reduce_vars: true,
+        toplevel: true,
+        typeofs: true,
+    }
+    input: {
+        if (A = console, "undefined" != typeof A)
+            for (var a = A, i = 0; i < 2; i++)
+                console.log(void 0 === A, void 0 === a),
+                A = void 0;
+    }
+    expect: {
+        if (A = console, "undefined" != typeof A)
+            for (var a = A, i = 0; i < 2; i++)
+                console.log(void 0 === A, (a, false)),
+                A = void 0;
+    }
+    expect_stdout: [
+        "false false",
+        "true false",
+    ]
+}
+
+reassign_for_in: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        passes: 2,
+        reduce_vars: true,
+        typeofs: true,
+    }
+    input: {
+        (A = console) && "undefined" != typeof A && function(a) {
+            for (var k in [ a = A, 42 ]) {
+                console.log(void 0 === A, void 0 === a);
+                A = void 0;
+            }
+        }();
+    }
+    expect: {
+        (A = console) && "undefined" != typeof A && function(a) {
+            for (var k in [ a = A, 42 ]) {
+                console.log(void 0 === A, (a, false));
+                A = void 0;
+            }
+        }();
+    }
+    expect_stdout: [
+        "false false",
+        "true false",
+    ]
+}
+
+reassign_iife: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        passes: 2,
+        typeofs: true,
+    }
+    input: {
+        A = console;
+        if ("undefined" == typeof A)
+            console.log("FAIL 1");
+        else (function() {
+            A = void 0;
+        })(console.log(void 0 === A ? "FAIL 2" : "PASS"));
+    }
+    expect: {
+        A = console;
+        "undefined" == typeof A ? console.log("FAIL 1") : function() {
+            A = void 0;
+        }(console.log((A, false) ? "FAIL 2" : "PASS"));
+    }
+    expect_stdout: "PASS"
+}
+
+reassign_property: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        passes: 2,
+        typeofs: true,
+    }
+    input: {
+        A = console;
+        if ("undefined" == typeof A)
+            console.log("FAIL 1");
+        else {
+            A.p = void 0;
+            console.log(void 0 === A ? "FAIL 2" : "PASS");
+        }
+    }
+    expect: {
+        A = console;
+        if ("undefined" == typeof A)
+            console.log("FAIL 1");
+        else {
+            A.p = void 0;
+            console.log((A, false) ? "FAIL 2" : "PASS");
+        }
+    }
+    expect_stdout: "PASS"
+}
+
 issue_3817: {
     options = {
         comparisons: true,

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

@@ -13,10 +13,10 @@ reduce_merge_const: {
         console.log(b);
     }
     expect: {
-        var b = console;
-        console.log(typeof b);
-        b = typeof b;
-        console.log(b);
+        var a = console;
+        console.log(typeof a);
+        a = typeof a;
+        console.log(a);
     }
     expect_stdout: [
         "object",
@@ -41,10 +41,10 @@ reduce_merge_let: {
     }
     expect: {
         "use strict";
-        var b = console;
-        console.log(typeof b);
-        b = typeof b;
-        console.log(b);
+        var a = console;
+        console.log(typeof a);
+        a = typeof a;
+        console.log(a);
     }
     expect_stdout: [
         "object",
@@ -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"

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() {
@@ -737,7 +749,7 @@ lift_sequence: {
     node_version: ">=4"
 }
 
-inline_nested_yield: {
+inline_nested: {
     options = {
         inline: true,
         sequences: true,
@@ -772,6 +784,118 @@ inline_nested_yield: {
     node_version: ">=4"
 }
 
+inline_nested_async: {
+    options = {
+        awaits: true,
+        inline: true,
+        sequences: true,
+        side_effects: true,
+        yields: true,
+    }
+    input: {
+        console.log("foo");
+        var a = async function*() {
+            console.log(await(yield* async function*() {
+                yield {
+                    then: r => r("bar"),
+                };
+                return "baz";
+            }()));
+        }();
+        console.log("moo");
+        a.next().then(function f(b) {
+            console.log(b.value);
+            b.done || a.next().then(f);
+        });
+        console.log("moz");
+    }
+    expect: {
+        console.log("foo");
+        var a = async function*() {
+            console.log((yield {
+                then: r => r("bar"),
+            }, await "baz"));
+        }();
+        console.log("moo"),
+        a.next().then(function f(b) {
+            console.log(b.value),
+            b.done || a.next().then(f);
+        }),
+        console.log("moz");
+    }
+    expect_stdout: [
+        "foo",
+        "moo",
+        "moz",
+        "bar",
+        "baz",
+        "undefined",
+    ]
+    node_version: ">=10"
+}
+
+inline_nested_block: {
+    options = {
+        if_return: true,
+        inline: true,
+        yields: true,
+    }
+    input: {
+        var a = function*() {
+            yield* function*() {
+                for (var a of [ "foo", "bar" ])
+                    yield a;
+                return "FAIL";
+            }();
+        }(), b;
+        do {
+            b = a.next();
+            console.log(b.value);
+        } while (!b.done);
+    }
+    expect: {
+        var a = function*() {
+            for (var a of [ "foo", "bar" ])
+                yield a;
+            "FAIL";
+        }(), b;
+        do {
+            b = a.next();
+            console.log(b.value);
+        } while (!b.done);
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "undefined",
+    ]
+    node_version: ">=4"
+}
+
+dont_inline_nested: {
+    options = {
+        inline: true,
+    }
+    input: {
+        var yield = "PASS";
+        (function*() {
+            (function() {
+                console.log(yield);
+            })();
+        })().next();
+    }
+    expect: {
+        var yield = "PASS";
+        (function*() {
+            (function() {
+                console.log(yield);
+            })();
+        })().next();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
 drop_body: {
     options = {
         side_effects: true,
@@ -852,10 +976,10 @@ issue_4454_2: {
         f("PASS");
     }
     expect: {
-        function f(b) {
-            (function*(c = console.log(b)) {})();
-            var b = 42..toString();
-            console.log(b);
+        function f(a) {
+            (function*(c = console.log(a)) {})();
+            var a = 42..toString();
+            console.log(a);
         }
         f("PASS");
     }
@@ -958,7 +1082,7 @@ issue_4639_1: {
         }().next().value());
     }
     expect_stdout: "PASS"
-    node_version: ">=4"
+    node_version: ">=4 <7 || >=8.7.0"
 }
 
 issue_4639_2: {
@@ -1165,9 +1289,9 @@ issue_5032_normal: {
             console.log(value);
             return value;
         }
-        function *f(c) {
-            var b = log(c), c = b;
-            log(b);
+        function *f(a) {
+            var a = log(a), c = a;
+            log(a);
             log(c);
         }
         f("PASS").next();
@@ -1247,12 +1371,13 @@ issue_5034: {
     node_version: ">=4"
 }
 
-issue_5076: {
+issue_5076_1: {
     options = {
         evaluate: true,
         hoist_vars: true,
-        passes: 2,
+        keep_fargs: false,
         pure_getters: "strict",
+        sequences: true,
         side_effects: true,
         toplevel: true,
         unused: true,
@@ -1269,9 +1394,156 @@ issue_5076: {
     }
     expect: {
         var a;
-        console.log("PASS");
+        console.log("PASS"),
         a = 42["a"];
     }
     expect_stdout: "PASS"
     node_version: ">=6"
 }
+
+issue_5076_2: {
+    options = {
+        evaluate: true,
+        hoist_vars: true,
+        keep_fargs: false,
+        passes: 2,
+        pure_getters: "strict",
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+        yields: true,
+    }
+    input: {
+        var a;
+        console.log("PASS");
+        var b = function*({
+            p: {},
+        }) {}({
+            p: { a } = 42,
+        });
+    }
+    expect: {
+        console.log("PASS");
+    }
+    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"
+}
+
+issue_5385_1: {
+    options = {
+        inline: true,
+    }
+    input: {
+        (async function*() {
+            (function() {
+                try {
+                    return console.log("foo");
+                } finally {
+                    return console.log("bar");
+                }
+                console.log("baz");
+            })();
+        })().next();
+        console.log("moo");
+    }
+    expect: {
+        (async function*() {
+            (function() {
+                try {
+                    return console.log("foo");
+                } finally {
+                    return console.log("bar");
+                }
+                console.log("baz");
+            })();
+        })().next();
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+    ]
+    node_version: ">=10"
+}
+
+issue_5385_2: {
+    options = {
+        inline: true,
+    }
+    input: {
+        (async function*() {
+            return function() {
+                try {
+                    return console.log("foo");
+                } finally {
+                    return console.log("bar");
+                }
+            }();
+        })().next();
+        console.log("moo");
+    }
+    expect: {
+        (async function*() {
+            return function() {
+                try {
+                    return console.log("foo");
+                } finally {
+                    return console.log("bar");
+                }
+            }();
+        })().next();
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+    ]
+    node_version: ">=10"
+}
+
+issue_5425: {
+    options = {
+        assignments: true,
+        ie: true,
+        toplevel: true,
+        unused: true,
+        yields: true,
+    }
+    input: {
+        var a = "FAIL";
+        var b = function* f() {}(a ? a = "PASS" : 42);
+        console.log(a, typeof f);
+    }
+    expect: {
+        var a = "FAIL";
+        (function* f() {})(a && (a = "PASS"));
+        console.log(a, typeof f);
+    }
+    expect_stdout: "PASS undefined"
+    node_version: ">=4"
+}

test/input/issue-505/output.js

@@ -1,5 +1,5 @@
 function test(a){
-"aaaaaaaaaaaaaaaa"
-;a(err,data),a(err,
+"aaaaaaaaaaaaaaaa";
+a(err,data),a(err,
 data)}
-//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIjAiXSwibmFtZXMiOlsidGVzdCIsImNhbGxiYWNrIiwiZXJyIiwiZGF0YSJdLCJtYXBwaW5ncyI6IkFBQUEsU0FBU0EsS0FBS0M7O0NBRVZBLEVBQVNDLElBQUtDLE1BQ2RGLEVBQVNDO0FBQUtDIn0=
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIjAiXSwibmFtZXMiOlsidGVzdCIsImNhbGxiYWNrIiwiZXJyIiwiZGF0YSJdLCJtYXBwaW5ncyI6IkFBQUEsU0FBU0E7SEFBS0M7QUFFVkE7aEJBQVNDLElBQUtDLE1BQ2RGLEVBQVNDLElBQUtDIn0=

test/input/reduce/diff_error.reduced.js

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

test/input/reduce/export_default.js

@@ -0,0 +1,17 @@
+var unused;
+export default class {
+    ____11111() {
+        a, b, c, d, e;
+        f, g, h, i, j;
+        k, l, m, n, o;
+        p, q, r, s, t;
+        u, v, w, x, y, z;
+        A, B, C, D, E;
+        F, G, H, I, J;
+        K, L, M, N, O;
+        P, Q, R, S, T;
+        U, V, W, X, Y, Z;
+        $, _;
+        unused;
+    }
+}

test/jetstream.js

@@ -69,6 +69,7 @@ if (typeof phantom == "undefined") {
             npm([
                 "install",
                 "graceful-fs@4.2.6",
+                "is-my-json-valid@2.20.5",
                 "phantomjs-prebuilt@2.1.14",
                 "--no-audit",
                 "--no-optional",

test/mocha/awaits.js

@@ -7,7 +7,7 @@ describe("async", function() {
             "function await() {}",
             "function(await) {}",
             "function() { await; }",
-            "function() { await:{} }",
+            "function() { await: {} }",
             "function() { var await; }",
             "function() { function await() {} }",
             "function() { try {} catch (await) {} }",

test/mocha/cli.js

@@ -2,6 +2,7 @@ var assert = require("assert");
 var exec = require("child_process").exec;
 var fs = require("fs");
 var run_code = require("../sandbox").run_code;
+var semver = require("semver");
 var to_ascii = require("../node").to_ascii;
 
 function read(path) {
@@ -12,10 +13,13 @@ describe("bin/uglifyjs", function() {
     var uglifyjscmd = '"' + process.argv[0] + '" bin/uglifyjs';
     it("Should produce a functional build when using --self", function(done) {
         this.timeout(30000);
-        var command = uglifyjscmd + ' --self -cm --wrap WrappedUglifyJS';
-        exec(command, {
-            maxBuffer: 1048576
-        }, function(err, stdout) {
+        var command = [
+            uglifyjscmd,
+            "--self",
+            semver.satisfies(process.version, "<=0.12") ? "-mc hoist_funs" : "-mc",
+            "--wrap WrappedUglifyJS",
+        ].join(" ");
+        exec(command, { maxBuffer: 1048576 }, function(err, stdout) {
             if (err) throw err;
             eval(stdout);
             assert.strictEqual(typeof WrappedUglifyJS, "object");
@@ -184,6 +188,30 @@ describe("bin/uglifyjs", function() {
             child.stdin.end(read("test/input/issue-3040/input.js"));
         }, 1000);
     });
+    it("Should work with --keep-fargs (mangle only)", function(done) {
+        var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fargs -m';
+        exec(command, function(err, stdout) {
+            if (err) throw err;
+            assert.strictEqual(stdout, "function f(x){return function(){function n(a){return a*a}return x(n)}}function g(op){return op(1)+op(2)}console.log(f(g)()==5);\n");
+            done();
+        });
+    });
+    it("Should work with --keep-fargs (mangle & compress)", function(done) {
+        var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fargs -m -c';
+        exec(command, function(err, stdout) {
+            if (err) throw err;
+            assert.strictEqual(stdout, "function f(x){return function(){return x(function(a){return a*a})}}function g(op){return op(1)+op(2)}console.log(5==f(g)());\n");
+            done();
+        });
+    });
+    it("Should work with keep_fargs under mangler options", function(done) {
+        var command = uglifyjscmd + ' test/input/issue-1431/sample.js -m keep_fargs=true';
+        exec(command, function(err, stdout) {
+            if (err) throw err;
+            assert.strictEqual(stdout, "function f(x){return function(){function n(a){return a*a}return x(n)}}function g(op){return op(1)+op(2)}console.log(f(g)()==5);\n");
+            done();
+        });
+    });
     it("Should work with --keep-fnames (mangle only)", function(done) {
         var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m';
         exec(command, function(err, stdout) {
@@ -193,10 +221,10 @@ describe("bin/uglifyjs", function() {
         });
     });
     it("Should work with --keep-fnames (mangle & compress)", function(done) {
-        var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m -c unused=false';
+        var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m -c';
         exec(command, function(err, stdout) {
             if (err) throw err;
-            assert.strictEqual(stdout, "function f(r){return function(){function n(n){return n*n}return r(n)}}function g(n){return n(1)+n(2)}console.log(5==f(g)());\n");
+            assert.strictEqual(stdout, "function f(n){return function(){return n(function n(r){return r*r})}}function g(n){return n(1)+n(2)}console.log(5==f(g)());\n");
             done();
         });
     });

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/let.js

@@ -1,5 +1,5 @@
 var assert = require("assert");
-var UglifyJS = require("../..");
+var UglifyJS = require("../node");
 
 describe("let", function() {
     this.timeout(30000);
@@ -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");
@@ -419,4 +418,71 @@ describe("test/reduce.js", function() {
         if (result.error) throw result.error;
         assert.deepEqual(result.warnings, []);
     });
+    it("Should handle thrown falsy values gracefully", function() {
+        var code = [
+            "throw 0;",
+            "setTimeout(null, 42);",
+        ].join("\n");
+        var result = reduce_test(code, {
+            mangle: false,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, [
+            "// Can't reproduce test failure",
+            "// minify options: {",
+            '//   "mangle": false',
+            "// }",
+        ].join("\n"));
+    });
+    it("Should transform `export default class` correctly", function() {
+        var result = reduce_test(read("test/input/reduce/export_default.js"), {
+            compress: false,
+            toplevel: true,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, [
+            "// Can't reproduce test failure",
+            "// minify options: {",
+            '//   "compress": false,',
+            '//   "toplevel": true',
+            "// }",
+        ].join("\n"));
+    });
+    it("Should transform `export default function` correctly", function() {
+        var code = [
+            "for (var k in this)",
+            "    console.log(k);",
+            "export default (function f() {});",
+            "console.log(k);",
+        ].join("\n");
+        var result = reduce_test(code, {
+            mangle: false,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, [
+            "// Can't reproduce test failure",
+            "// minify options: {",
+            '//   "mangle": false',
+            "// }",
+        ].join("\n"));
+    });
+    it("Should transform `export default (42)` correctly", function() {
+        var code = [
+            "export default (42);",
+            "for (var k in this)",
+            "    console.log(k);",
+        ].join("\n");
+        var result = reduce_test(code, {
+            compress: false,
+            mangle: false,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, [
+            "// Can't reproduce test failure",
+            "// minify options: {",
+            '//   "compress": false,',
+            '//   "mangle": false',
+            "// }",
+        ].join("\n"));
+    });
 });

test/mocha/sourcemaps.js

@@ -205,8 +205,8 @@ describe("sourcemaps", function() {
             });
             if (result.error) throw result.error;
             assert.strictEqual(result.code, [
-                "var Foo=function(){console.log(3)};new Foo;var bar=function(o){return o};",
-                "//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIiwiMSJdLCJuYW1lcyI6WyJGb28iLCJjb25zb2xlIiwibG9nIiwiYmFyIl0sIm1hcHBpbmdzIjoiQUFBQSxJQUFNQSxJQUFJLFdBQWdCQyxRQUFRQyxJQUFJLElBQVMsSUFBSUYsSUNBbkQsSUFBSUcsSUFDQSxTQUFjQSxHQUNWLE9BQU9BIn0=",
+                "var Foo=function(){console.log(3)},bar=(new Foo,function(o){return o});",
+                "//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIiwiMSJdLCJuYW1lcyI6WyJGb28iLCJjb25zb2xlIiwibG9nIiwiYmFyIl0sIm1hcHBpbmdzIjoiQUFBQSxJQUFNQSxJQUFJLFdBQWdCQyxRQUFRQyxJQUFJLElDQWxDQyxLREEyQyxJQUFJSCxJQ0MvQyxTQUFjRyxHQUNWLE9BQU9BIn0=",
             ].join("\n"));
             assert.deepEqual(result.warnings, [ "WARN: inline source map not found: 1" ]);
         });
@@ -362,7 +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

@@ -1,37 +1,42 @@
 var assert = require("assert");
 var exec = require("child_process").exec;
+var semver = require("semver");
 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 | " +
-            uglifyjs + " -p spidermonkey -cm";
-
-        exec(command, {
-            maxBuffer: 1048576
-        }, function(err, stdout) {
+        var options = semver.satisfies(process.version, "<=0.12") ? "-mc hoist_funs" : "-mc";
+        var command = [
+            [
+                uglifyjs,
+                "--self",
+                options,
+                "--wrap SpiderUglify",
+                "-o spidermonkey",
+            ].join(" "),
+            [
+                uglifyjs,
+                "-p spidermonkey",
+                options,
+            ].join(" "),
+        ].join(" | ");
+        exec(command, { maxBuffer: 1048576 }, 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(
-            UglifyJS.AST_Node.from_mozilla_ast(ast).print_to_string(),
-            input
-        );
+        assert.strictEqual(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/mocha/yields.js

@@ -6,7 +6,7 @@ describe("generator", function() {
         [
             "function yield() {}",
             "function(yield) {}",
-            "function() { yield:{} }",
+            "function() { yield: {} }",
             "function() { var yield; }",
             "function() { function yield() {} }",
             "function() { try {} catch (yield) {} }",

test/sandbox.js

@@ -26,9 +26,11 @@ exports.run_code = semver.satisfies(process.version, "0.8") ? function(code, top
     return stdout;
 } : semver.satisfies(process.version, "<0.12") ? run_code_vm : function(code, toplevel, timeout) {
     if ([
-        /\basync[ \t]*\([\s\S]*?\)[ \t]*=>/,
         /\b(async[ \t]+function|Promise|setImmediate|setInterval|setTimeout)\b/,
-        /\basync([ \t]+|[ \t]*#|[ \t]*\*[ \t]*)[^\s()[\]{},.&|!~=*%/+-]+(\s*\(|[ \t]*=>)/,
+        /\basync([ \t]+|[ \t]*#)[^\s()[\]{}#:;,.&|!~=*%/+-]+(\s*\(|[ \t]*=>)/,
+        /\basync[ \t]*\*[ \t]*[^\s()[\]{}#:;,.&|!~=*%/+-]+\s*\(/,
+        /\basync([ \t]*\*)?[ \t]*\[[\s\S]*?\]\s*\(/,
+        /\basync[ \t]*\([\s\S]*?\)[ \t]*=>/,
     ].some(function(pattern) {
         return pattern.test(code);
     })) {
@@ -50,14 +52,22 @@ exports.same_stdout = semver.satisfies(process.version, "0.12") ? function(expec
     return typeof expected == typeof actual && strip_func_ids(expected) == strip_func_ids(actual);
 };
 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) {
+    var count = 0, has_default = "", imports = [], strict_mode = "";
+    code = code.replace(/^\s*("|')use strict\1\s*;?/, function(match) {
+        strict_mode = match;
+        return "";
+    }).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 (/^export\s+default/.test(match)) has_default = "var _uglify_export_default_;";
         if (!header) return "";
         if (header.length == 1) return "0, " + header;
-        return header.slice(0, -1) + " _" + ++count + header.slice(-1);
+        var name = "_uglify_export_default_";
+        if (/^class\b/.test(header)) do {
+            name = "_uglify_export_default_" + ++count;
+        } while (code.indexOf(name) >= 0);
+        return header.slice(0, -1) + " " + name + 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, ",");
@@ -71,7 +81,7 @@ exports.patch_module_statements = function(code) {
         return "";
     });
     imports.push("");
-    return imports.join("\n") + code;
+    return strict_mode + has_default + imports.join("\n") + code;
 };
 
 function is_error(result) {
@@ -146,7 +156,8 @@ function setup(global, builtins, setup_log, setup_tty) {
                     delete ex[name];
                 }
             }
-            process.stderr.write(inspect(value) + "\n\n-----===== UNCAUGHT EXCEPTION =====-----\n\n");
+            var marker = "\n\n-----===== UNCAUGHT EXCEPTION =====-----\n\n";
+            process.stderr.write(marker + inspect(value) + marker);
             throw ex;
         }).on("unhandledRejection", function() {});
     }
@@ -202,13 +213,11 @@ 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", {
-            value: function() {
-                return "[object global]";
-            },
-        });
-    }
+    global.__proto__ = Object.defineProperty(Object.create(global.__proto__), "toString", {
+        value: function() {
+            return "[object global]";
+        },
+    });
 
     function self() {
         return this;
@@ -254,8 +263,11 @@ 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 });
-        return strip_color_codes(stdout);
+        vm.runInContext(toplevel ? "(function(){\n" + code + "\n})();" : code, ctx, { timeout: timeout });
+        // 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 +277,7 @@ 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(;|$))?/, function(directive) {
             return directive + setup_code;
@@ -278,22 +290,26 @@ function run_code_exec(code, toplevel, timeout) {
         timeout: timeout || 5000,
     });
     if (result.status === 0) return result.stdout;
+    var msg = ("" + result.stderr).replace(/\r\n/g, "\n");
     if (result.error && result.error.code == "ETIMEDOUT" || /FATAL ERROR:/.test(msg)) {
         return new Error("Script execution timed out.");
     }
     if (result.error) return result.error;
-    var msg = result.stderr.replace(/\r\n/g, "\n");
-    var end = msg.indexOf("\n\n-----===== UNCAUGHT EXCEPTION =====-----\n\n");
+    var match = /\n([^:\s]*Error)(?:: ([\s\S]+?))?\n(    at [\s\S]+)\n$/.exec(msg);
+    var marker = "\n\n-----===== UNCAUGHT EXCEPTION =====-----\n\n";
+    var start = msg.indexOf(marker) + marker.length;
+    var end = msg.indexOf(marker, start);
     var details;
     if (end >= 0) {
-        details = msg.slice(0, end).replace(/<([1-9][0-9]*) empty items?>/g, function(match, count) {
+        details = msg.slice(start, end).replace(/<([1-9][0-9]*) empty items?>/g, function(match, count) {
             return new Array(+count).join();
         });
         try {
             details = vm.runInNewContext("(" + details + ")");
         } catch (e) {}
+    } else if (!match) {
+        return new Error("Script execution aborted.");
     }
-    var match = /\n([^:\s]*Error)(?:: ([\s\S]+?))?\n(    at [\s\S]+)\n$/.exec(msg);
     if (!match) return details;
     var ex = new global[match[1]](match[2]);
     ex.stack = ex.stack.slice(0, ex.stack.indexOf("    at ")) + match[3];

test/ufuzz/index.js

@@ -128,7 +128,7 @@ for (var i = 2; i < process.argv.length; ++i) {
 
 var SUPPORT = function(matrix) {
     for (var name in matrix) {
-        matrix[name] = typeof sandbox.run_code(matrix[name]) == "string";
+        matrix[name] = !sandbox.is_error(sandbox.run_code(matrix[name]));
     }
     return matrix;
 }({
@@ -334,6 +334,7 @@ var VAR_NAMES = [
     "arguments",
     "async",
     "await",
+    "let",
     "yield",
 ];
 var INITIAL_NAMES_LEN = VAR_NAMES.length;
@@ -352,7 +353,7 @@ var TYPEOF_OUTCOMES = [
 ];
 
 var avoid_vars = [];
-var block_vars = [];
+var block_vars = [ "let" ];
 var lambda_vars = [];
 var unique_vars = [];
 var classes = [];
@@ -399,7 +400,7 @@ 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;
@@ -1823,7 +1824,13 @@ function createClassLiteral(recurmax, stmtDepth, canThrow, name) {
             declared.push(internal);
         }
         if (SUPPORT.class_field && rng(2)) {
-            s += internal || createObjectKey(recurmax, stmtDepth, canThrow);
+            if (internal) {
+                s += internal;
+            } else if (fixed && bug_static_class_field) {
+                s += getDotKey();
+            } else {
+                s += createObjectKey(recurmax, stmtDepth, canThrow);
+            }
             if (rng(5)) {
                 async = bug_async_class_await && fixed && 0;
                 generator = false;
@@ -2027,6 +2034,7 @@ function removeAvoidVar(name) {
 function isBannedKeyword(name) {
     switch (name) {
       case "arguments":
+      case "let":
         return in_class;
       case "await":
         return async !== false;
@@ -2078,8 +2086,8 @@ if (require.main !== module) {
     return;
 }
 
-function run_code(code, toplevel) {
-    return sandbox.run_code(sandbox.patch_module_statements(code), toplevel);
+function run_code(code, toplevel, timeout) {
+    return sandbox.run_code(sandbox.patch_module_statements(code), toplevel, timeout);
 }
 
 function writeln(stream, msg) {
@@ -2108,7 +2116,7 @@ function try_beautify(code, toplevel, result, printfn, options) {
     } else if (options) {
         var uglified = UglifyJS.minify(beautified.code, JSON.parse(options));
         var expected, actual;
-        if (typeof uglify_code != "string" || uglified.error) {
+        if (sandbox.is_error(uglify_code) || uglified.error) {
             expected = uglify_code;
             actual = uglified.error;
         } else {
@@ -2137,7 +2145,7 @@ function log_suspects(minify_options, component) {
     var defs = default_options[component];
     var toplevel = sandbox.has_toplevel(minify_options);
     var suspects = Object.keys(defs).filter(function(name) {
-        var flip = name == "keep_fargs";
+        var flip = component == "compress" && name == "keep_fargs";
         if (flip !== (name in options ? options : defs)[name]) {
             var m = JSON.parse(JSON.stringify(minify_options));
             var o = JSON.parse(JSON.stringify(options));
@@ -2145,7 +2153,7 @@ function log_suspects(minify_options, component) {
             m[component] = o;
             m.validate = true;
             var result = UglifyJS.minify(original_code, m);
-            if (typeof uglify_code != "string") {
+            if (sandbox.is_error(uglify_code)) {
                 return !sandbox.same_stdout(uglify_code, result.error);
             } else if (result.error) {
                 errorln("Error testing options." + component + "." + name);
@@ -2173,7 +2181,7 @@ function log_suspects_global(options, toplevel) {
         m[component] = false;
         m.validate = true;
         var result = UglifyJS.minify(original_code, m);
-        if (typeof uglify_code != "string") {
+        if (sandbox.is_error(uglify_code)) {
             return !sandbox.same_stdout(uglify_code, result.error);
         } else if (result.error) {
             errorln("Error testing options." + component);
@@ -2202,7 +2210,16 @@ function log(options) {
     errorln();
     errorln();
     errorln("//-------------------------------------------------------------");
-    if (typeof uglify_code == "string") {
+    if (sandbox.is_error(uglify_code)) {
+        errorln("// !!! uglify failed !!!");
+        errorln(uglify_code);
+        if (original_erred) {
+            errorln();
+            errorln();
+            errorln("original stacktrace:");
+            errorln(original_result);
+        }
+    } else {
         errorln("// uglified code");
         try_beautify(uglify_code, toplevel, uglify_result, errorln);
         errorln();
@@ -2211,15 +2228,6 @@ function log(options) {
         errorln(original_result);
         errorln("uglified result:");
         errorln(uglify_result);
-    } else {
-        errorln("// !!! uglify failed !!!");
-        errorln(uglify_code);
-        if (errored) {
-            errorln();
-            errorln();
-            errorln("original stacktrace:");
-            errorln(original_result);
-        }
     }
     errorln("//-------------------------------------------------------------");
     if (!ok) {
@@ -2288,7 +2296,7 @@ function fuzzy_match(original, uglified) {
     return true;
 
     function collect(input, nums) {
-        return input.replace(/-?([1-9][0-9]*(\.[0-9]+)?|0\.[0-9]+)(e-?[1-9][0-9]*)?/ig, function(num) {
+        return input.replace(/-?([1-9][0-9]*(\.[0-9]+)?|0\.[0-9]+)(e-?[1-9][0-9]*)?/gi, function(num) {
             return "<|" + nums.push(+num) + "|>";
         });
     }
@@ -2350,7 +2358,7 @@ 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;
@@ -2424,22 +2432,23 @@ var beautify_options = {
     },
 };
 var minify_options = require("./options.json");
-if (typeof sandbox.run_code("A:if (0) B:; else B:;") != "string") {
+if (sandbox.is_error(sandbox.run_code("A:if (0) B:; else B:;"))) {
     minify_options.forEach(function(o) {
         if (!("mangle" in o)) o.mangle = {};
         if (o.mangle) o.mangle.v8 = true;
     });
 }
 var bug_async_arrow_rest = function() {};
-if (SUPPORT.arrow && SUPPORT.async && SUPPORT.rest && typeof sandbox.run_code("async (a = f(...[], b)) => 0;") != "string") {
+if (SUPPORT.arrow && SUPPORT.async && SUPPORT.rest && sandbox.is_error(sandbox.run_code("async (a = f(...[], b)) => 0;"))) {
     bug_async_arrow_rest = function(ex) {
         return ex.name == "SyntaxError" && ex.message == "Rest parameter must be last formal parameter";
     };
 }
-var bug_async_class_await = SUPPORT.async && SUPPORT.class_field && typeof sandbox.run_code("var await; async function f() { class A { static p = await; } }") != "string";
-var bug_for_of_async = SUPPORT.for_await_of && typeof sandbox.run_code("var async; for (async of []);") != "string";
-var bug_for_of_var = SUPPORT.for_of && SUPPORT.let && typeof sandbox.run_code("try {} catch (e) { for (var e of []); }") != "string";
-if (SUPPORT.destructuring && typeof sandbox.run_code("console.log([ 1 ], {} = 2);") != "string") {
+var bug_async_class_await = SUPPORT.async && SUPPORT.class_field && sandbox.is_error(sandbox.run_code("var await; async function f() { class A { static p = await; } }"));
+var bug_for_of_async = SUPPORT.for_await_of && sandbox.is_error(sandbox.run_code("var async; for (async of []);"));
+var bug_for_of_var = SUPPORT.for_of && SUPPORT.let && sandbox.is_error(sandbox.run_code("try {} catch (e) { for (var e of []); }"));
+var bug_static_class_field = SUPPORT.class_field && sandbox.is_error(sandbox.run_code("class A { static 42; static get 42() {} }"));
+if (SUPPORT.destructuring && sandbox.is_error(sandbox.run_code("console.log([ 1 ], {} = 2);"))) {
     beautify_options.output.v8 = true;
     minify_options.forEach(function(o) {
         if (!("output" in o)) o.output = {};
@@ -2448,7 +2457,7 @@ if (SUPPORT.destructuring && typeof sandbox.run_code("console.log([ 1 ], {} = 2)
 }
 beautify_options = JSON.stringify(beautify_options);
 minify_options = minify_options.map(JSON.stringify);
-var original_code, original_result, errored;
+var original_code, original_result, original_erred;
 var uglify_code, uglify_result, ok;
 for (var round = 1; round <= num_iterations; round++) {
     process.stdout.write(round + " of " + num_iterations + "\r");
@@ -2456,7 +2465,7 @@ for (var round = 1; round <= num_iterations; round++) {
     original_code = createTopLevelCode();
     var orig_result = [ run_code(original_code), run_code(original_code, true) ];
     if (orig_result.some(function(result, toplevel) {
-        if (typeof result == "string") return;
+        if (!sandbox.is_error(result)) return;
         println();
         println();
         println("//=============================================================");
@@ -2467,8 +2476,10 @@ for (var round = 1; round <= num_iterations; round++) {
         println("original result:");
         println(result);
         println();
-        // ignore v8 parser bug
-        return bug_async_arrow_rest(result);
+            // ignore v8 parser bug
+        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);
@@ -2476,33 +2487,44 @@ for (var round = 1; round <= num_iterations; round++) {
         o.validate = true;
         uglify_code = UglifyJS.minify(original_code, o);
         original_result = orig_result[toplevel ? 1 : 0];
-        errored = typeof original_result != "string";
+        original_erred = sandbox.is_error(original_result);
         if (!uglify_code.error) {
             uglify_code = uglify_code.code;
             uglify_result = run_code(uglify_code, toplevel);
             ok = sandbox.same_stdout(original_result, uglify_result);
+            var uglify_erred = sandbox.is_error(uglify_result);
             // ignore v8 parser bug
-            if (!ok && bug_async_arrow_rest(uglify_result)) ok = true;
+            if (!ok && uglify_erred && bug_async_arrow_rest(uglify_result)) ok = true;
+            // ignore runtime platform bugs
+            if (!ok && uglify_erred && 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)) {
-                    // ignore difference in error message
-                    ok = true;
-                } else {
+            if (!ok) {
+                if (original_erred && is_error_timeout(original_result)) {
+                    if (uglify_erred && is_error_timeout(uglify_result)) {
+                        // ignore difference in error message
+                        ok = true;
+                    } else {
+                        // ignore spurious time-outs
+                        if (!orig_result[toplevel ? 3 : 2]) orig_result[toplevel ? 3 : 2] = run_code(original_code, toplevel, 10000);
+                        ok = sandbox.same_stdout(orig_result[toplevel ? 3 : 2], uglify_result);
+                    }
+                } else if (uglify_erred && is_error_timeout(uglify_result)) {
                     // ignore spurious time-outs
-                    if (!orig_result[toplevel ? 3 : 2]) orig_result[toplevel ? 3 : 2] = run_code(original_code, toplevel, 10000);
-                    ok = sandbox.same_stdout(orig_result[toplevel ? 3 : 2], uglify_result);
+                    var waited_result = run_code(uglify_code, toplevel, 10000);
+                    ok = sandbox.same_stdout(original_result, waited_result);
                 }
             }
             // ignore declaration order of global variables
             if (!ok && !toplevel) {
-                ok = sandbox.same_stdout(run_code(sort_globals(original_code)), run_code(sort_globals(uglify_code)));
+                if (!(original_erred && original_result.name == "SyntaxError") && !(uglify_erred && uglify_result.name == "SyntaxError")) {
+                    ok = sandbox.same_stdout(run_code(sort_globals(original_code)), run_code(sort_globals(uglify_code)));
+                }
             }
             // ignore numerical imprecision caused by `unsafe_math`
-            if (!ok && o.compress && o.compress.unsafe_math && typeof original_result == typeof uglify_result) {
-                if (typeof original_result == "string") {
+            if (!ok && o.compress && o.compress.unsafe_math) {
+                if (typeof original_result == "string" && typeof uglify_result == "string") {
                     ok = fuzzy_match(original_result, uglify_result);
-                } else if (sandbox.is_error(original_result)) {
+                } else if (original_erred && uglify_erred) {
                     ok = original_result.name == uglify_result.name && fuzzy_match(original_result.message, uglify_result.message);
                 }
                 if (!ok) {
@@ -2511,20 +2533,19 @@ for (var round = 1; round <= num_iterations; round++) {
                 }
             }
             // ignore difference in error message caused by Temporal Dead Zone
-            if (!ok && errored && uglify_result.name == "ReferenceError" && original_result.name == "ReferenceError") ok = true;
+            if (!ok && original_erred && uglify_erred && original_result.name == "ReferenceError" && uglify_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";\n' + original_code, toplevel);
-                var uglify_strict = run_code('"use strict";\n' + uglify_code, toplevel);
-                if (typeof original_strict != "string") {
-                    ok = typeof uglify_strict != "string";
+                if (uglify_erred && /^(Syntax|Type)Error$/.test(uglify_result.name)) {
+                    ok = sandbox.is_error(original_strict);
                 } else {
-                    ok = sandbox.same_stdout(original_strict, uglify_strict);
+                    ok = sandbox.same_stdout(original_strict, uglify_result);
                 }
             }
             // ignore difference in error message caused by `import` symbol redeclaration
-            if (!ok && errored && /\bimport\b/.test(original_code)) {
-                if (is_error_redeclaration(uglify_result) && is_error_redeclaration(original_result)) ok = true;
+            if (!ok && original_erred && uglify_erred && /\bimport\b/.test(original_code)) {
+                if (is_error_redeclaration(original_result) && is_error_redeclaration(uglify_result)) ok = true;
             }
             // ignore difference due to `__proto__` assignment
             if (!ok && /\b__proto__\b/.test(original_code)) {
@@ -2533,24 +2554,32 @@ for (var round = 1; round <= num_iterations; round++) {
                 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;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_in(original_result) && is_error_in(uglify_result)) ok = true;
+            }
             // ignore difference in error message caused by spread syntax
-            if (!ok && errored && is_error_spread(uglify_result) && is_error_spread(original_result)) ok = true;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_spread(original_result) && is_error_spread(uglify_result)) ok = true;
+            }
             // ignore difference in depth of termination caused by infinite recursion
-            if (!ok && errored && is_error_recursion(original_result)) {
-                if (is_error_recursion(uglify_result) || typeof uglify_result == "string") ok = true;
+            if (!ok && original_erred && is_error_recursion(original_result)) {
+                if (!uglify_erred || is_error_recursion(uglify_result)) ok = true;
             }
             // ignore difference in error message caused by destructuring
-            if (!ok && errored && is_error_destructuring(uglify_result) && is_error_destructuring(original_result)) {
-                ok = true;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_destructuring(original_result) && is_error_destructuring(uglify_result)) ok = true;
             }
             // ignore difference in error message caused by call on class
-            if (!ok && errored && is_error_class_constructor(uglify_result) && is_error_class_constructor(original_result)) {
-                ok = true;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_class_constructor(original_result) && is_error_class_constructor(uglify_result)) {
+                    ok = true;
+                }
             }
             // ignore difference in error message caused by setting getter-only property
-            if (!ok && errored && is_error_getter_only_property(uglify_result) && is_error_getter_only_property(original_result)) {
-                ok = true;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_getter_only_property(original_result) && is_error_getter_only_property(uglify_result)) {
+                    ok = true;
+                }
             }
             // ignore errors above when caught by try-catch
             if (!ok) {
@@ -2562,7 +2591,7 @@ for (var round = 1; round <= num_iterations; round++) {
             }
         } else {
             uglify_code = uglify_code.error;
-            ok = errored && uglify_code.name == original_result.name;
+            ok = original_erred && uglify_code.name == original_result.name;
         }
         if (verbose || (verbose_interval && !(round % INTERVAL_COUNT)) || !ok) log(options);
         if (!ok && isFinite(num_iterations)) {

test/ufuzz/options.json

@@ -26,6 +26,7 @@
             "passes": 1e6,
             "unsafe": true
         },
+        "keep_fargs": true,
         "keep_fnames": true,
         "toplevel": true
     },