v3.14.3

fixes #5159

.github/workflows/build.yml

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

.github/workflows/ci.yml

@@ -7,14 +7,9 @@ jobs:
   test:
     strategy:
       matrix:
-        node: [ '0.8', '0.10', '0.12', '4', '6', '8', '10', '12', '14', latest ]
+        node: [ '0.10', '0.12', '4', '6', '8', '10', '12', '14', 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

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

bin/uglifyjs

@@ -101,7 +101,7 @@ function process_option(name, no_value) {
                 "  --config-file <file>                     Read minify() options from JSON file.",
                 "  -d, --define <expr>[=value]              Global definitions.",
                 "  -e, --enclose [arg[,...][:value[,...]]]  Embed everything in a big function, with configurable argument(s) & value(s).",
-                "  --ie8                                    Support non-standard Internet Explorer 8.",
+                "  --ie                                     Support non-standard Internet Explorer.",
                 "  --keep-fnames                            Do not mangle/drop function names. Useful for code relying on Function.prototype.name.",
                 "  --name-cache <file>                      File to hold mangled name mappings.",
                 "  --rename                                 Force symbol expansion.",
@@ -110,6 +110,7 @@ function process_option(name, no_value) {
                 "  --source-map [options]                   Enable source map/specify source map options.",
                 "  --timings                                Display operations run time on STDERR.",
                 "  --toplevel                               Compress and/or mangle variables in toplevel scope.",
+                "  --v8                                     Support non-standard Chrome & Node.js.",
                 "  --validate                               Perform validation during AST manipulations.",
                 "  --verbose                                Print diagnostic messages.",
                 "  --warn                                   Print warning messages.",
@@ -145,9 +146,11 @@ function process_option(name, no_value) {
         options[name] = read_value();
         break;
       case "annotations":
+      case "ie":
       case "ie8":
       case "timings":
       case "toplevel":
+      case "v8":
       case "validate":
       case "webkit":
         options[name] = true;

lib/ast.js

@@ -1289,13 +1289,14 @@ function must_be_expressions(node, prop, allow_spread, allow_hole) {
     });
 }
 
-var AST_Call = DEFNODE("Call", "args expression optional pure", {
+var AST_Call = DEFNODE("Call", "args expression optional pure terminal", {
     $documentation: "A function call expression",
     $propdoc: {
         args: "[AST_Node*] array of arguments",
         expression: "[AST_Node] expression to invoke as function",
         optional: "[boolean] whether the expression is optional chaining",
         pure: "[string/S] marker for side-effect-free call expression",
+        terminal: "[boolean] whether the chain has ended",
     },
     walk: function(visitor) {
         var node = this;
@@ -1316,6 +1317,7 @@ var AST_New = DEFNODE("New", null, {
     $documentation: "An object instantiation.  Derives from a function call since it has exactly the same properties",
     _validate: function() {
         if (this.optional) throw new Error("optional must be false");
+        if (this.terminal) throw new Error("terminal must be false");
     },
 }, AST_Call);
 
@@ -1338,23 +1340,23 @@ var AST_Sequence = DEFNODE("Sequence", "expressions", {
     },
 });
 
-var AST_PropAccess = DEFNODE("PropAccess", "expression optional property", {
+function root_expr(prop) {
+    while (prop instanceof AST_PropAccess) prop = prop.expression;
+    return prop;
+}
+
+var AST_PropAccess = DEFNODE("PropAccess", "expression optional property terminal", {
     $documentation: "Base class for property access expressions, i.e. `a.foo` or `a[\"foo\"]`",
     $propdoc: {
         expression: "[AST_Node] the “container” expression",
         optional: "[boolean] whether the expression is optional chaining",
         property: "[AST_Node|string] the property to access.  For AST_Dot this is always a plain string, while for AST_Sub it's an arbitrary AST_Node",
+        terminal: "[boolean] whether the chain has ended",
     },
-    getProperty: function() {
+    get_property: function() {
         var p = this.property;
-        if (p instanceof AST_Constant) {
-            return p.value;
-        }
-        if (p instanceof AST_UnaryPrefix
-            && p.operator == "void"
-            && p.expression instanceof AST_Constant) {
-            return;
-        }
+        if (p instanceof AST_Constant) return p.value;
+        if (p instanceof AST_UnaryPrefix && p.operator == "void" && p.expression instanceof AST_Constant) return;
         return p;
     },
     _validate: function() {
@@ -1759,11 +1761,11 @@ var AST_SymbolLambda = DEFNODE("SymbolLambda", null, {
 
 var AST_SymbolDefClass = DEFNODE("SymbolDefClass", null, {
     $documentation: "Symbol defining a class",
-}, AST_SymbolLet);
+}, AST_SymbolConst);
 
 var AST_SymbolClass = DEFNODE("SymbolClass", null, {
     $documentation: "Symbol naming a class expression",
-}, AST_SymbolLet);
+}, AST_SymbolConst);
 
 var AST_SymbolCatch = DEFNODE("SymbolCatch", null, {
     $documentation: "Symbol naming the exception in catch",

lib/minify.js

@@ -76,6 +76,7 @@ function minify(files, options) {
             annotations: undefined,
             compress: {},
             enclose: false,
+            ie: false,
             ie8: false,
             keep_fnames: false,
             mangle: {},
@@ -96,7 +97,8 @@ function minify(files, options) {
         var timings = options.timings && { start: Date.now() };
         if (options.rename === undefined) options.rename = options.compress && options.mangle;
         if (options.annotations !== undefined) set_shorthand("annotations", options, [ "compress", "output" ]);
-        if (options.ie8) set_shorthand("ie8", options, [ "compress", "mangle", "output" ]);
+        if (options.ie8) options.ie = options.ie || options.ie8;
+        if (options.ie) set_shorthand("ie", options, [ "compress", "mangle", "output" ]);
         if (options.keep_fnames) set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
         if (options.toplevel) set_shorthand("toplevel", options, [ "compress", "mangle" ]);
         if (options.v8) set_shorthand("v8", options, [ "mangle", "output" ]);
@@ -106,7 +108,7 @@ function minify(files, options) {
             options.mangle = defaults(options.mangle, {
                 cache: options.nameCache && (options.nameCache.vars || {}),
                 eval: false,
-                ie8: false,
+                ie: false,
                 keep_fnames: false,
                 properties: false,
                 reserved: [],

lib/mozilla-ast.js

@@ -556,7 +556,9 @@
             return node;
         },
         ChainExpression: function(M) {
-            return from_moz(M.expression);
+            var node = from_moz(M.expression);
+            node.terminal = true;
+            return node;
         },
     };
 
@@ -868,7 +870,7 @@
 
     def_to_moz(AST_PropAccess, function To_Moz_MemberExpression(M) {
         var computed = M instanceof AST_Sub;
-        return {
+        var expr = {
             type: "MemberExpression",
             object: to_moz(M.expression),
             computed: computed,
@@ -878,6 +880,10 @@
                 name: M.property,
             },
         };
+        return M.terminal ? {
+            type: "ChainExpression",
+            expression: expr,
+        } : expr;
     });
 
     def_to_moz(AST_Unary, function To_Moz_Unary(M) {

lib/output.js

@@ -56,7 +56,7 @@ function OutputStream(options) {
         braces           : false,
         comments         : false,
         galio            : false,
-        ie8              : false,
+        ie               : false,
         indent_level     : 4,
         indent_start     : 0,
         inline_script    : true,
@@ -193,7 +193,7 @@ function OutputStream(options) {
               case "\t": return "\\t";
               case "\b": return "\\b";
               case "\f": return "\\f";
-              case "\x0B": return options.ie8 ? "\\x0B" : "\\v";
+              case "\x0B": return options.ie ? "\\x0B" : "\\v";
               case "\u2028": return "\\u2028";
               case "\u2029": return "\\u2029";
               case "\ufeff": return "\\ufeff";
@@ -790,35 +790,26 @@ function OutputStream(options) {
         if (p instanceof AST_Unary) return true;
     });
 
-    function lhs_has_optional(node, output) {
-        var p = output.parent();
-        if (p instanceof AST_PropAccess && p.expression === node && is_lhs(p, output.parent(1))) {
-            // ++(foo?.bar).baz
-            // (foo?.()).bar = baz
-            do {
-                if (node.optional) return true;
-                node = node.expression;
-            } while (node.TYPE == "Call" || node instanceof AST_PropAccess);
-        }
+    function need_chain_parens(node, parent) {
+        if (!node.terminal) return false;
+        if (!(parent instanceof AST_Call || parent instanceof AST_PropAccess)) return false;
+        return parent.expression === node;
     }
 
     PARENS(AST_PropAccess, function(output) {
         var node = this;
         var p = output.parent();
-        if (p instanceof AST_New) {
-            if (p.expression !== node) return false;
-            // i.e. new (foo().bar)
-            //
-            // if there's one call into this subtree, then we need
-            // parens around it too, otherwise the call will be
-            // interpreted as passing the arguments to the upper New
-            // expression.
-            do {
-                node = node.expression;
-            } while (node instanceof AST_PropAccess);
-            return node.TYPE == "Call";
-        }
-        return lhs_has_optional(node, output);
+        // i.e. new (foo().bar)
+        //
+        // if there's one call into this subtree, then we need
+        // parens around it too, otherwise the call will be
+        // interpreted as passing the arguments to the upper New
+        // expression.
+        if (p instanceof AST_New && p.expression === node && root_expr(node).TYPE == "Call") return true;
+        // (foo?.bar)()
+        // (foo?.bar).baz
+        // new (foo?.bar)()
+        return need_chain_parens(node, p);
     });
 
     PARENS(AST_Call, function(output) {
@@ -833,7 +824,10 @@ function OutputStream(options) {
             var g = output.parent(1);
             if (g instanceof AST_Assign && g.left === p) return true;
         }
-        return lhs_has_optional(node, output);
+        // (foo?.())()
+        // (foo?.()).bar
+        // new (foo?.())()
+        return need_chain_parens(node, p);
     });
 
     PARENS(AST_New, function(output) {
@@ -980,7 +974,6 @@ function OutputStream(options) {
     DEFPRINT(AST_Do, function(output) {
         var self = this;
         output.print("do");
-        output.space();
         make_block(self.body, output);
         output.space();
         output.print("while");
@@ -997,7 +990,6 @@ function OutputStream(options) {
         output.with_parens(function() {
             self.condition.print(output);
         });
-        output.space();
         force_statement(self.body, output);
     });
     DEFPRINT(AST_For, function(output) {
@@ -1027,7 +1019,6 @@ function OutputStream(options) {
                 self.step.print(output);
             }
         });
-        output.space();
         force_statement(self.body, output);
     });
     function print_for_enum(prefix, infix) {
@@ -1042,7 +1033,6 @@ function OutputStream(options) {
                 output.space();
                 self.object.print(output);
             });
-            output.space();
             force_statement(self.body, output);
         };
     }
@@ -1056,7 +1046,6 @@ function OutputStream(options) {
         output.with_parens(function() {
             self.expression.print(output);
         });
-        output.space();
         force_statement(self.body, output);
     });
     DEFPRINT(AST_ExportDeclaration, function(output) {
@@ -1295,7 +1284,7 @@ function OutputStream(options) {
     function make_then(self, output) {
         var b = self.body;
         if (output.option("braces") && !(b instanceof AST_Const || b instanceof AST_Let)
-            || output.option("ie8") && b instanceof AST_Do)
+            || output.option("ie") && b instanceof AST_Do)
             return make_block(b, output);
         // The squeezer replaces "block"-s that contain only a single
         // statement with the statement itself; technically, the AST
@@ -1325,16 +1314,16 @@ function OutputStream(options) {
         output.with_parens(function() {
             self.condition.print(output);
         });
-        output.space();
         if (self.alternative) {
             make_then(self, output);
             output.space();
             output.print("else");
-            output.space();
-            if (self.alternative instanceof AST_If)
+            if (self.alternative instanceof AST_If) {
+                output.space();
                 self.alternative.print(output);
-            else
+            } else {
                 force_statement(self.alternative, output);
+            }
         } else {
             force_statement(self.body, output);
         }
@@ -1520,7 +1509,7 @@ function OutputStream(options) {
         var expr = self.expression;
         expr.print(output);
         var prop = self.property;
-        if (output.option("ie8") && RESERVED_WORDS[prop]) {
+        if (output.option("ie") && RESERVED_WORDS[prop]) {
             output.print(self.optional ? "?.[" : "[");
             output.add_mapping(self.end);
             output.print_string(prop);
@@ -1634,7 +1623,19 @@ function OutputStream(options) {
         var self = this;
         var key = print_property_key(self, output);
         var value = self.value;
-        if (key && value instanceof AST_SymbolDeclaration && key == get_symbol_name(value)) return;
+        if (key) {
+            if (value instanceof AST_DefaultValue) {
+                if (value.name instanceof AST_Symbol && key == get_symbol_name(value.name)) {
+                    output.space();
+                    output.print("=");
+                    output.space();
+                    value.value.print(output);
+                    return;
+                }
+            } else if (value instanceof AST_Symbol) {
+                if (key == get_symbol_name(value)) return;
+            }
+        }
         output.colon();
         value.print(output);
     });
@@ -1683,28 +1684,21 @@ function OutputStream(options) {
 
     function print_property_key(self, output) {
         var key = self.key;
-        if (key instanceof AST_Node) {
-            output.with_square(function() {
-                key.print(output);
-            });
-        } else if (output.option("quote_keys")) {
-            output.print_string(key);
+        if (key instanceof AST_Node) return output.with_square(function() {
+            key.print(output);
+        });
+        var quote = self.start && self.start.quote;
+        if (output.option("quote_keys") || quote && output.option("keep_quoted_props")) {
+            output.print_string(key, quote);
         } else if ("" + +key == key && key >= 0) {
             output.print(make_num(key));
+        } else if (self.private) {
+            output.print_name(key);
+        } else if (RESERVED_WORDS[key] ? !output.option("ie") : is_identifier_string(key)) {
+            output.print_name(key);
+            return key;
         } else {
-            var quote = self.start && self.start.quote;
-            if (self.private) {
-                output.print_name(key);
-            } else if (RESERVED_WORDS[key] ? !output.option("ie8") : is_identifier_string(key)) {
-                if (quote && output.option("keep_quoted_props")) {
-                    output.print_string(key, quote);
-                } else {
-                    output.print_name(key);
-                    return key;
-                }
-            } else {
-                output.print_string(key, quote);
-            }
+            output.print_string(key, quote);
         }
     }
     DEFPRINT(AST_ObjectKeyVal, function(output) {
@@ -1836,6 +1830,7 @@ function OutputStream(options) {
         } else if (stat instanceof AST_EmptyStatement) {
             output.force_semicolon();
         } else {
+            output.space();
             stat.print(output);
         }
     }
@@ -1884,6 +1879,7 @@ function OutputStream(options) {
     }
 
     function make_block(stmt, output) {
+        output.space();
         if (stmt instanceof AST_EmptyStatement) {
             print_braced_empty(stmt, output);
         } else if (stmt instanceof AST_BlockStatement) {

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");
@@ -1192,7 +1200,7 @@ function parse($TEXT, options) {
         if (await || !is("punc", ";")) {
             init = is("keyword", "const")
                 ? (next(), const_(true))
-                : is("keyword", "let")
+                : is("name", "let") && is_vardefs()
                 ? (next(), let_(true))
                 : is("keyword", "var")
                 ? (next(), var_(true))
@@ -1535,12 +1543,18 @@ function parse($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 +1569,6 @@ function parse($TEXT, options) {
             if (!is("operator", "*")) return function_(AST_Defun);
             next();
             return function_(AST_GeneratorDefun);
-          case "let":
-            next();
-            var node = let_();
-            semicolon();
-            return node;
           case "var":
             next();
             var node = var_();
@@ -1720,6 +1729,11 @@ function parse($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(),
@@ -1818,10 +1832,7 @@ function parse($TEXT, options) {
         if (is("punc")) {
             switch (start.value) {
               case "`":
-                var tmpl = template(null);
-                tmpl.start = start;
-                tmpl.end = prev();
-                return subscripts(tmpl, allow_calls);
+                return subscripts(template(null), allow_calls);
               case "(":
                 next();
                 if (is("punc", ")")) {
@@ -2133,7 +2144,7 @@ function parse($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");
     }
 
@@ -2230,6 +2241,7 @@ function parse($TEXT, options) {
     }
 
     function template(tag) {
+        var start = tag ? tag.start : S.token;
         var read = S.input.context().read_template;
         var strings = [];
         var expressions = [];
@@ -2240,58 +2252,60 @@ function parse($TEXT, options) {
         }
         next();
         return new AST_Template({
+            start: start,
             expressions: expressions,
             strings: strings,
             tag: tag,
+            end: prev(),
         });
     }
 
-    var subscripts = function(expr, allow_calls, optional) {
+    function subscripts(expr, allow_calls) {
         var start = expr.start;
-        if (is("punc", "[")) {
-            next();
-            var prop = expression();
-            expect("]");
-            return subscripts(new AST_Sub({
-                start: start,
-                optional: optional,
-                expression: expr,
-                property: prop,
-                end: prev(),
-            }), allow_calls);
-        }
-        if (allow_calls && is("punc", "(")) {
-            next();
-            var call = new AST_Call({
-                start: start,
-                optional: optional,
-                expression: expr,
-                args: expr_list(")", !options.strict),
-                end: prev(),
-            });
-            return subscripts(call, true);
-        }
-        if (optional || is("punc", ".")) {
-            if (!optional) next();
-            return subscripts(new AST_Dot({
-                start: start,
-                optional: optional,
-                expression: expr,
-                property: as_name(),
-                end: prev(),
-            }), allow_calls);
-        }
-        if (is("punc", "`")) {
-            var tmpl = template(expr);
-            tmpl.start = expr.start;
-            tmpl.end = prev();
-            return subscripts(tmpl, allow_calls);
-        }
-        if (is("operator", "?") && is_token(peek(), "punc", ".")) {
-            next();
-            next();
-            return subscripts(expr, allow_calls, true);
+        var optional = null;
+        while (true) {
+            if (is("operator", "?") && is_token(peek(), "punc", ".")) {
+                next();
+                next();
+                optional = expr;
+            }
+            if (is("punc", "[")) {
+                next();
+                var prop = expression();
+                expect("]");
+                expr = new AST_Sub({
+                    start: start,
+                    optional: optional === expr,
+                    expression: expr,
+                    property: prop,
+                    end: prev(),
+                });
+            } else if (allow_calls && is("punc", "(")) {
+                next();
+                expr = new AST_Call({
+                    start: start,
+                    optional: optional === expr,
+                    expression: expr,
+                    args: expr_list(")", !options.strict),
+                    end: prev(),
+                });
+            } else if (optional === expr || is("punc", ".")) {
+                if (optional !== expr) next();
+                expr = new AST_Dot({
+                    start: start,
+                    optional: optional === expr,
+                    expression: expr,
+                    property: as_name(),
+                    end: prev(),
+                });
+            } else if (is("punc", "`")) {
+                if (optional) croak("Invalid template on optional chain");
+                expr = template(expr);
+            } else {
+                break;
+            }
         }
+        if (optional) expr.terminal = true;
         if (expr instanceof AST_Call && !expr.pure) {
             var start = expr.start;
             var comments = start.comments_before;
@@ -2305,7 +2319,7 @@ function parse($TEXT, options) {
             }
         }
         return expr;
-    };
+    }
 
     function maybe_unary(no_in) {
         var start = S.token;

lib/scope.js

@@ -118,7 +118,7 @@ function is_lhs(node, parent) {
 AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
     options = defaults(options, {
         cache: null,
-        ie8: false,
+        ie: false,
     });
 
     // pass 1: setup scope chaining and handle definitions
@@ -211,7 +211,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             entangle(defun, scope);
         } else if (node instanceof AST_SymbolLambda) {
             var def = defun.def_function(node, node.name == "arguments" ? undefined : defun);
-            if (options.ie8) def.defun = defun.parent_scope.resolve();
+            if (options.ie) def.defun = defun.parent_scope.resolve();
         } else if (node instanceof AST_SymbolLet) {
             var def = scope.def_variable(node);
             if (exported) def.exported = true;
@@ -351,7 +351,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
     self.walk(tw);
 
     // pass 3: fix up any scoping issue with IE8
-    if (options.ie8) self.walk(new TreeWalker(function(node) {
+    if (options.ie) self.walk(new TreeWalker(function(node) {
         if (node instanceof AST_SymbolCatch) {
             var scope = node.thedef.defun;
             if (scope.name instanceof AST_SymbolLambda && scope.name.name == node.name) {
@@ -572,7 +572,7 @@ AST_Symbol.DEFMETHOD("definition", function() {
 function _default_mangler_options(options) {
     options = defaults(options, {
         eval        : false,
-        ie8         : false,
+        ie          : false,
         keep_fnames : false,
         reserved    : [],
         toplevel    : false,

lib/utils.js

@@ -143,7 +143,7 @@ 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;
     });

package.json

@@ -3,7 +3,7 @@
   "description": "JavaScript parser, mangler/compressor and beautifier toolkit",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.13.10",
+  "version": "3.14.3",
   "engines": {
     "node": ">=0.8.0"
   },

test/compress/arrows.js

@@ -556,6 +556,75 @@ reduce_iife_3: {
     node_version: ">=4"
 }
 
+reduce_lambda_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f = () => {
+            console.log(a, b);
+        };
+        var a = "foo", b = 42;
+        f();
+        b = "bar";
+        f();
+    }
+    expect: {
+        var f = () => {
+            console.log("foo", b);
+        };
+        var b = 42;
+        f();
+        b = "bar";
+        f();
+    }
+    expect_stdout: [
+        "foo 42",
+        "foo bar",
+    ]
+    node_version: ">=4"
+}
+
+reduce_lambda_2: {
+    options = {
+        evaluate: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function(f, a, b) {
+            f = () => {
+                console.log(a, b);
+            };
+            a = "foo", b = 42;
+            f();
+            b = "bar";
+            f();
+        })();
+    }
+    expect: {
+        (function(f, a, b) {
+            f = () => {
+                console.log("foo", b);
+            };
+            b = 42;
+            f();
+            b = "bar";
+            f();
+        })();
+    }
+    expect_stdout: [
+        "foo 42",
+        "foo bar",
+    ]
+    node_version: ">=4"
+}
+
 single_use_recursive: {
     options = {
         reduce_vars: true,

test/compress/awaits.js

@@ -227,7 +227,7 @@ inline_await_1_trim: {
         console.log("PASS");
     }
     expect: {
-        void 0;
+        0;
         console.log("PASS");
     }
     expect_stdout: "PASS"
@@ -571,7 +571,7 @@ drop_async_1: {
     }
     expect: {
         console.log(function(a) {
-            void (a *= 7);
+            a *= 7;
             return a;
         }(6));
     }
@@ -1774,7 +1774,7 @@ issue_5001: {
     }
     expect: {
         var a = 0;
-        void a++;
+        a++;
         console.log(a ? "PASS" : "FAIL");
     }
     expect_stdout: "PASS"
@@ -2023,3 +2023,192 @@ issue_5034: {
     expect_stdout: "PASS"
     node_version: ">=8"
 }
+
+issue_5070: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                for await (var a of console.log("PASS"));
+            } catch (e) {}
+        })();
+    }
+    expect: {
+        (async function() {
+            try {
+                for await (var a of console.log("PASS"));
+            } catch (e) {}
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=10"
+}
+
+issue_5157_async_function: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        async function f() {
+            throw "FAIL";
+        }
+        (async function() {
+            try {
+                return await f();
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect: {
+        async function f() {
+            throw "FAIL";
+        }
+        (async function() {
+            try {
+                return await f();
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5157_async_iife: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                return await async function() {
+                    throw "FAIL";
+                }();
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect: {
+        (async function() {
+            try {
+                return await async function() {
+                    throw "FAIL";
+                }();
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5157_promise: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        var p = new Promise(function(resolve, reject) {
+            reject("FAIL");
+        });
+        (async function() {
+            try {
+                return await p;
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect: {
+        var p = new Promise(function(resolve, reject) {
+            reject("FAIL");
+        });
+        (async function() {
+            try {
+                return await p;
+            } catch (e) {
+                return "PASS";
+            }
+        })().then(console.log);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5159_1: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                throw "foo";
+            } catch (e) {
+                return await "bar";
+            } finally {
+                console.log("baz");
+            }
+        })().catch(console.log).then(console.log);
+        console.log("moo");
+    }
+    expect: {
+        (async function() {
+            try {
+                throw "foo";
+            } catch (e) {
+                return await "bar";
+            } finally {
+                console.log("baz");
+            }
+        })().catch(console.log).then(console.log);
+        console.log("moo");
+    }
+    expect_stdout: [
+        "moo",
+        "baz",
+        "bar",
+    ]
+    node_version: ">=8"
+}
+
+issue_5159_2: {
+    options = {
+        awaits: true,
+        side_effects: true,
+    }
+    input: {
+        (async function() {
+            try {
+                throw "foo";
+            } catch (e) {
+                return await "bar";
+            }
+        })().catch(console.log).then(console.log);
+        console.log("baz");
+    }
+    expect: {
+        (async function() {
+            try {
+                throw "foo";
+            } catch (e) {
+                return "bar";
+            }
+        })().catch(console.log).then(console.log);
+        console.log("baz");
+    }
+    expect_stdout: [
+        "baz",
+        "bar",
+    ]
+    node_version: ">=8"
+}

test/compress/booleans.js

@@ -406,6 +406,27 @@ conditional_chain: {
     expect_stdout: "PASS"
 }
 
+negated_if: {
+    options = {
+        booleans: true,
+        conditionals: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(function(a) {
+            if (!a)
+                return a ? "FAIL" : "PASS";
+        }(!console));
+    }
+    expect: {
+        console.log(function(a) {
+            if (!a)
+                return "PASS";
+        }(!console));
+    }
+    expect_stdout: "PASS"
+}
+
 issue_3465_1: {
     options = {
         booleans: true,
@@ -634,3 +655,45 @@ issue_5028_3: {
     }
     expect_stdout: "-1"
 }
+
+issue_5041_1: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        var a = 42;
+        if (a)
+            if ([ a = null ])
+                if (a)
+                    console.log("FAIL");
+                else
+                    console.log("PASS");
+    }
+    expect: {
+        var a = 42;
+        a && [ a = null ] && (a ? console.log("FAIL") : console.log("PASS"));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5041_2: {
+    options = {
+        booleans: true,
+        conditionals: true,
+    }
+    input: {
+        var a;
+        if (!a)
+            if (a = 42)
+                if (a)
+                    console.log("PASS");
+                else
+                    console.log("FAIL");
+    }
+    expect: {
+        var a;
+        a || (a = 42) && (a ? console.log("PASS") : console.log("FAIL"));
+    }
+    expect_stdout: "PASS"
+}

test/compress/classes.js

@@ -1157,7 +1157,7 @@ issue_4705: {
 
 issue_4720: {
     options = {
-        ie8: true,
+        ie: true,
         reduce_vars: true,
         toplevel: true,
         unused: true,
@@ -1629,7 +1629,7 @@ issue_4951_2: {
 
 issue_4962_1: {
     options = {
-        ie8: true,
+        ie: true,
         inline: true,
         reduce_vars: true,
         unused: true,
@@ -1656,7 +1656,7 @@ issue_4962_1: {
 
 issue_4962_2: {
     options = {
-        ie8: true,
+        ie: true,
         inline: true,
         reduce_vars: true,
         unused: true,
@@ -1875,3 +1875,225 @@ issue_5015_3: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_5053_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        try {
+            console.log(new class A {
+                constructor() {
+                    A = 42;
+                }
+            }());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            console.log(new class A {
+                constructor() {
+                    A = 42;
+                }
+            }());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5053_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        "use strict";
+        try {
+            console.log(new class A {
+                f() {
+                    A = 42;
+                }
+            }().f());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            console.log(new class A {
+                f() {
+                    A = 42;
+                }
+            }().f());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5053_3: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        try {
+            console.log(new class A {
+                p = A = 42;
+            }().p);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            console.log(new class A {
+                p = A = 42;
+            }().p);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5053_4: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        class A {
+            constructor() {
+                A = 42;
+            }
+        }
+        try {
+            console.log(new A());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        class A {
+            constructor() {
+                A = 42;
+            }
+        }
+        try {
+            console.log(new A());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5082_1: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            class B {
+                static P = new A();
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            new A();
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5082_2: {
+    options = {
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            class A {
+                p = console.log("PASS");
+                q() {}
+            }
+            class B {
+                static P = new A();
+            }
+        })();
+    }
+    expect: {
+        void new class {
+            p = console.log("PASS");
+            q() {}
+        }();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}
+
+issue_5142: {
+    options = {
+        evaluate: true,
+        merge_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0, b;
+        if (++a)
+            new class {
+                p = b = null;
+                constructor(c) {
+                    console.log(c ? "FAIL" : "PASS");
+                }
+            }(b, a);
+    }
+    expect: {
+        var a = 0, b;
+        if (++a)
+            new class {
+                p = b = null;
+                constructor(c) {
+                    console.log(c ? "FAIL" : "PASS");
+                }
+            }(b, 1);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}

test/compress/collapse_vars.js

@@ -6008,7 +6008,7 @@ issue_3215_1: {
     options = {
         collapse_vars: true,
         evaluate: true,
-        ie8: false,
+        ie: false,
         inline: true,
         passes: 2,
         side_effects: true,
@@ -6030,7 +6030,7 @@ issue_3215_2: {
     options = {
         collapse_vars: true,
         evaluate: true,
-        ie8: true,
+        ie: true,
         inline: true,
         passes: 2,
         side_effects: true,
@@ -6055,7 +6055,7 @@ issue_3215_3: {
     options = {
         collapse_vars: true,
         evaluate: true,
-        ie8: false,
+        ie: false,
         inline: true,
         passes: 2,
         side_effects: true,
@@ -6078,7 +6078,7 @@ issue_3215_4: {
     options = {
         collapse_vars: true,
         evaluate: true,
-        ie8: true,
+        ie: true,
         inline: true,
         passes: 2,
         side_effects: true,
@@ -9412,3 +9412,73 @@ issue_4977_2: {
     }
     expect_stdout: "PASS PASS"
 }
+
+issue_5112_1: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        console.log(function(a) {
+            try {
+                try {
+                    if (console + (a = "PASS", ""))
+                        return "FAIL 1";
+                    a.p;
+                } catch (e) {}
+            } finally {
+                return a;
+            }
+        }("FAIL 2"));
+    }
+    expect: {
+        console.log(function(a) {
+            try {
+                try {
+                    if (console + (a = "PASS", ""))
+                        return "FAIL 1";
+                    a.p;
+                } catch (e) {}
+            } finally {
+                return a;
+            }
+        }("FAIL 2"));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5112_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        console.log(function(a) {
+            try {
+                return function() {
+                    try {
+                        if (console + (a = "PASS", ""))
+                            return "FAIL 1";
+                        a.p;
+                    } catch (e) {}
+                }();
+            } finally {
+                return a;
+            }
+        }("FAIL 2"));
+    }
+    expect: {
+        console.log(function(a) {
+            try {
+                return function() {
+                    try {
+                        if (console + (a = "PASS", ""))
+                            return "FAIL 1";
+                        a.p;
+                    } catch (e) {}
+                }();
+            } finally {
+                return a;
+            }
+        }("FAIL 2"));
+    }
+    expect_stdout: "PASS"
+}

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/const.js

@@ -486,7 +486,7 @@ do_continue: {
 
 catch_ie8_1: {
     options = {
-        ie8: true,
+        ie: true,
         unused: true,
     }
     input: {
@@ -506,7 +506,7 @@ catch_ie8_1: {
 catch_ie8_2: {
     options = {
         dead_code: true,
-        ie8: true,
+        ie: true,
         passes: 2,
         toplevel: true,
         unused: true,
@@ -727,7 +727,7 @@ issue_4193: {
 
 issue_4195: {
     mangle = {
-        ie8: true,
+        ie: true,
     }
     input: {
         console.log(function f(a) {
@@ -1131,7 +1131,7 @@ issue_4225: {
 
 issue_4229: {
     options = {
-        ie8: true,
+        ie: true,
         side_effects: true,
     }
     input: {
@@ -1151,7 +1151,7 @@ issue_4229: {
 
 issue_4231: {
     options = {
-        ie8: true,
+        ie: true,
         side_effects: true,
     }
     input: {

test/compress/dead-code.js

@@ -1633,3 +1633,39 @@ issue_5030: {
     expect_stdout: "PASS"
     node_version: ">=0.12"
 }
+
+issue_5106_1: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        console.log(typeof function(a) {
+            return a = arguments;
+        }("FAIL")[0]);
+    }
+    expect: {
+        console.log(typeof function(a) {
+            return a = arguments;
+        }("FAIL")[0]);
+    }
+    expect_stdout: "object"
+}
+
+issue_5106_2: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        "use strict";
+        console.log(function(a) {
+            return a = arguments;
+        }("PASS")[0]);
+    }
+    expect: {
+        "use strict";
+        console.log(function(a) {
+            return arguments;
+        }("PASS")[0]);
+    }
+    expect_stdout: "PASS"
+}

test/compress/default-values.js

@@ -70,7 +70,7 @@ object_shorthand_assign: {
         ({ a = "PASS" } = 42);
         console.log(a);
     }
-    expect_exact: '({a:a="PASS"}=42);console.log(a);'
+    expect_exact: '({a="PASS"}=42);console.log(a);'
     expect_stdout: "PASS"
     node_version: ">=6"
 }
@@ -80,7 +80,7 @@ object_shorthand_declaration: {
         var { a = "PASS" } = 42;
         console.log(a);
     }
-    expect_exact: 'var{a:a="PASS"}=42;console.log(a);'
+    expect_exact: 'var{a="PASS"}=42;console.log(a);'
     expect_stdout: "PASS"
     node_version: ">=6"
 }
@@ -91,7 +91,7 @@ object_shorthand_function: {
             console.log(a);
         })(42);
     }
-    expect_exact: '(function({a:a="PASS"}){console.log(a)})(42);'
+    expect_exact: '(function({a="PASS"}){console.log(a)})(42);'
     expect_stdout: "PASS"
     node_version: ">=6"
 }
@@ -149,7 +149,7 @@ process_boolean_returns: {
     }
     expect: {
         console.log(function(a = console.log("FAIL 1")) {
-            return a() ? "PASS" : "FAIL 2";
+            return 42 ? "PASS" : "FAIL 2";
         }(function() {
             return 1;
         }));
@@ -245,21 +245,64 @@ maintain_if: {
     node_version: ">=6"
 }
 
-reduce_value: {
+reduce_funarg: {
     options = {
         evaluate: true,
+        keep_fargs: false,
         reduce_vars: true,
         unused: true,
     }
     input: {
-        console.log(function(a = "PASS") {
-            return a;
-        }());
+        console.log(...function(a = "foo", b = "bar", c = "baz") {
+            return [ a, b, c ];
+        }(void 0, null));
     }
     expect: {
-        console.log("PASS");
+        console.log(...function() {
+            return [ "foo", null, "baz" ];
+        }());
     }
-    expect_stdout: "PASS"
+    expect_stdout: "foo null baz"
+    node_version: ">=6"
+}
+
+reduce_array: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var [ a = "foo", b = "bar", c = "baz" ] = [ void 0, null ];
+        console.log(a, b, c);
+    }
+    expect: {
+        var [ c = "baz" ] = [];
+        console.log("foo", null, c);
+    }
+    expect_stdout: "foo null baz"
+    node_version: ">=6"
+}
+
+reduce_object: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var { a = "foo", b = "bar", c = "baz" } = { a: void 0, b: null };
+        console.log(a, b, c);
+    }
+    expect: {
+        var { c = "baz" } = {};
+        console.log("foo", null, c);
+    }
+    expect_stdout: "foo null baz"
     node_version: ">=6"
 }
 
@@ -525,6 +568,20 @@ retain_empty_iife: {
     node_version: ">=6"
 }
 
+drop_new_function: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        new function(a = console.log("PASS")) {}();
+    }
+    expect: {
+        void console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 retain_fargs: {
     options = {
         unused: true,
@@ -676,7 +733,7 @@ unused_value_var_2: {
         console.log(a);
     }
     expect: {
-        var [ a ] = [ "PASS" ];
+        var a = [ "PASS" ][0];
         console.log(a);
     }
     expect_stdout: "PASS"
@@ -1257,7 +1314,7 @@ issue_4468: {
     expect: {
         (function() {
             var {
-                [console.log("PASS")]: b = 0,
+                [console.log("PASS")]: b,
             } = 0;
         })();
     }
@@ -1416,6 +1473,7 @@ issue_4502_1: {
     expect: {
         (function() {
             var a = "PASS";
+            void 0,
             console.log(a),
             a++,
             void 0;
@@ -1439,6 +1497,7 @@ issue_4502_2: {
     expect: {
         (function() {
             var a = "PASS";
+            void 0,
             console.log(a),
             a++,
             void 0;
@@ -1664,7 +1723,7 @@ issue_4588_2_evaluate: {
 
 issue_4817: {
     options = {
-        ie8: true,
+        ie: true,
         inline: true,
         unused: true,
     }
@@ -1698,7 +1757,7 @@ issue_4854: {
         }());
     }
     expect: {
-        console.log(void ([] = "foo"));
+        console.log(void 0);
     }
     expect_stdout: "undefined"
     node_version: ">=6"
@@ -1754,3 +1813,128 @@ issue_4994: {
     expect_stdout: "PASS"
     node_version: ">=6"
 }
+
+issue_5057_1: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        sequences: true,
+        unused: true,
+    }
+    input: {
+        var a = 42;
+        (function() {
+            var b = function(c = (console.log("foo"), b = a)) {
+                a && console.log("bar");
+            }();
+        })();
+    }
+    expect: {
+        var a = 42;
+        console.log("foo"),
+        void (a && console.log("bar"));
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+    node_version: ">=6"
+}
+
+issue_5057_2: {
+    options = {
+        inline: true,
+        unused: true,
+    }
+    input: {
+        (function f(a) {
+            (function(b = console.log("FAIL")) {})(a);
+        })(42);
+        console.log(typeof b);
+    }
+    expect: {
+        (function(a) {
+            [ b = console.log("FAIL") ] = [ a ],
+            void 0;
+            var b;
+        })(42);
+        console.log(typeof b);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+issue_5057_3: {
+    options = {
+        inline: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            (function f(b) {
+                (function(a = console.log("FAIL 1")) {})(b);
+                console.log(a);
+            })("FAIL 2");
+        })("PASS");
+    }
+    expect: {
+        (function(a) {
+            (function(b) {
+                (function(a = console.log("FAIL 1")) {})(b);
+                console.log(a);
+            })("FAIL 2");
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5065: {
+    options = {
+        pure_getters: "strict",
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var [ a = console.log("PASS") ] = [ (A = 42).p ];
+    }
+    expect: {
+        var [ a = console.log("PASS") ] = [ (A = 42).p ];
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5138_1: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log(function(a, b = a = "FAIL") {
+            return a;
+        }() && "PASS");
+    }
+    expect: {
+        console.log(function(a, b = a = "FAIL") {
+            return a;
+        }() && "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5138_2: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log(function(a, b = a = "FAIL 1") {
+            return a;
+        }(null, "FAIL 2") || "PASS");
+    }
+    expect: {
+        console.log((null, "PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/compress/destructured.js

@@ -1105,7 +1105,7 @@ drop_unused_1: {
             try {
                 throw 42;
             } catch (a) {
-                var [ a ] = [];
+                var a = [][0];
             }
         }
     }
@@ -1138,6 +1138,175 @@ drop_unused_2: {
     node_version: ">=6"
 }
 
+drop_hole: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var [ a ] = [ , ];
+        console.log(a);
+    }
+    expect: {
+        var a = [][0];
+        console.log(a);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=6"
+}
+
+keep_key_1: {
+    options = {
+        evaluate: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = {
+            [(console.log("PASS"), 42)]: null,
+        });
+    }
+    expect: {
+        ({} = {
+            [(console.log("PASS"), 42)]: 0,
+        });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_key_2: {
+    options = {
+        evaluate: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { 42: a } = { [(console.log("PASS"), 42)](){} };
+    }
+    expect: {
+        var {} = { [(console.log("PASS"), 42)]: 0 };
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_key_2_pure_getters: {
+    options = {
+        evaluate: true,
+        pure_getters: "strict",
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var { 42: a } = { [(console.log("PASS"), 42)](){} };
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_reference: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = [ {}, 42 ];
+        var [ b, c ] = a;
+        console.log(a[0] === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = [ {}, 42 ];
+        var [ b ] = a;
+        console.log(a[0] === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+maintain_position_assign: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(([ , ] = [ , "PASS" ])[1]);
+    }
+    expect: {
+        console.log([ , "PASS" ][1]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+maintain_position_var: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        A = "FAIL";
+        var [ a, b ] = [ A ];
+        console.log(b || "PASS");
+    }
+    expect: {
+        A = "FAIL";
+        var [ , b ] = [ A ];
+        console.log(b || "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+side_effects_array: {
+    options = {
+        unused: true,
+    }
+    input: {
+        try {
+            var [ a ] = 42;
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            var [ a ] = 42;
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+side_effects_object: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = null, b = console, { c } = 42;
+        try {
+            c[a = "PASS"];
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect: {
+        var a = null, c = (console, 42["c"]);
+        try {
+            c[a = "PASS"];
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 join_vars: {
     options = {
         conditionals: true,
@@ -1860,7 +2029,7 @@ issue_4321: {
 
 issue_4323: {
     options = {
-        ie8: true,
+        ie: true,
         inline: true,
         merge_vars: true,
         reduce_vars: true,
@@ -1958,7 +2127,7 @@ issue_4372_2: {
     }
     expect: {
         var a;
-        [ a ] = [ "PASS", "FAIL" ];
+        [ a ] = a = [ "PASS", "FAIL" ];
         console.log(a);
     }
     expect_stdout: "PASS"
@@ -2647,3 +2816,412 @@ issue_5017: {
     expect_stdout: "PASS"
     node_version: ">=6"
 }
+
+issue_5071_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var a;
+        console.log(([ , a ] = [ "PA", , ]).join("SS"));
+    }
+    expect: {
+        var a;
+        console.log(([ , a ] = [ "PA", , ]).join("SS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5071_2: {
+    options = {
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        var a;
+        ([ a ] = []).p = console.log("PASS");
+    }
+    expect: {
+        var a;
+        ([ a ] = []).p = console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_getter: {
+    options = {
+        evaluate: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { get [(console.log("PASS"), 42)]() {} });
+    }
+    expect: {
+        ({} = { [(console.log("PASS"), 42)]: 0 });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_getter_pure_getters: {
+    options = {
+        evaluate: true,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { get [(console.log("PASS"), 42)]() {} });
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_setter: {
+    options = {
+        evaluate: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { set [(console.log("PASS"), 42)](v) {} });
+    }
+    expect: {
+        ({} = { [(console.log("PASS"), 42)]: 0 });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_setter_pure_getters: {
+    options = {
+        evaluate: true,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { set [(console.log("PASS"), 42)](v) {} });
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_method: {
+    options = {
+        evaluate: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { [(console.log("PASS"), 42)]() {} });
+    }
+    expect: {
+        ({} = { [(console.log("PASS"), 42)]: 0 });
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5074_method_pure_getters: {
+    options = {
+        evaluate: true,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        ({} = { [(console.log("PASS"), 42)]() {} });
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5085_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        var [ b ] = [ 42, a ], c = b ? 0 : a = "FAIL";
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        var b = [ 42 ][0];
+        b;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5085_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        side_effects: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function(b) {
+            [ b ] = [ 42, a ];
+            var c = b ? 0 : a = "FAIL";
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        (function(b) {
+            b = [ 42 ][0];
+        })();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5087_1: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        properties: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function() {
+            (function() {
+                (function([ b ]) {
+                    b && console.log(b);
+                })([ a ]);
+            })();
+        })();
+    }
+    expect: {
+        var a = "PASS";
+        (function() {
+            var b;
+            (b = a) && console.log(b);
+        })();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5087_2: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        passes: 2,
+        properties: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function() {
+            (function() {
+                (function([ b ]) {
+                    b && console.log(b);
+                })([ a ]);
+            })();
+        })();
+    }
+    expect: {
+        var a = "PASS";
+        a && console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5114_1: {
+    options = {
+        inline: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function({}, a) {})(42);
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        [ {} ] = [ 42 ],
+        void 0;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5114_2: {
+    options = {
+        inline: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function f([], a) {
+            f.length;
+        })([]);
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        0;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5114_3: {
+    options = {
+        inline: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function f(a, {}) {
+            f.length;
+        })(null, 42);
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        0;
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5153_array_assign: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = function*() {
+            yield b;
+        }(), b;
+        [ b ] = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = function*() {
+            yield b;
+        }(), b;
+        [ b ] = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5153_array_var: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = function*() {
+            yield b;
+        }(), [ b ] = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = function*() {
+            yield b;
+        }(), [ b ] = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5153_object_assign: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = {
+            get p() {
+                return b;
+            },
+        }, b;
+        ({
+            p: b
+        } = b = a);
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = {
+            get p() {
+                return b;
+            },
+        }, b;
+        ({
+            p: b
+        } = b = a);
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5153_object_var: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = {
+            get p() {
+                return b;
+            },
+        }, {
+            p: b
+        } = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect: {
+        var a = {
+            get p() {
+                return b;
+            },
+        }, {
+            p: b
+        } = b = a;
+        console.log(a === b ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/compress/drop-unused.js

@@ -795,9 +795,9 @@ issue_1656: {
         beautify: true,
     }
     input: {
-        for(var a=0;;);
+        for (var a=0;;);
     }
-    expect_exact: "for (;;) ;"
+    expect_exact: "for (;;);"
 }
 
 issue_1709: {
@@ -1110,7 +1110,7 @@ issue_1838: {
     }
     expect_exact: [
         "function f() {",
-        "    for (a; c; ) ;",
+        "    for (a; c; );",
         "}",
     ]
 }
@@ -1557,9 +1557,9 @@ issue_2665: {
     }
     expect: {
         var a = 1;
-        !function g() {
+        (function g() {
             a-- && g();
-        }();
+        })();
         console.log(a);
     }
     expect_stdout: "-1"
@@ -2345,7 +2345,7 @@ function_argument_reference: {
 
 function_parameter_ie8: {
     options = {
-        ie8: true,
+        ie: true,
         reduce_vars: true,
         unused: true,
     }
@@ -3081,7 +3081,8 @@ issue_4235: {
     }
     expect: {
         void function() {
-            var f = console.log(f);
+            var f;
+            console.log(f);
         }();
     }
     expect_stdout: "undefined"
@@ -3229,7 +3230,7 @@ issue_4558_1: {
 issue_4558_2: {
     options = {
         evaluate: true,
-        ie8: true,
+        ie: true,
         reduce_vars: true,
         unused: true,
     }
@@ -3378,7 +3379,7 @@ issue_4834: {
     }
     expect: {
         try {
-            void b.p;
+            b.p;
         } catch (e) {
             console.log("PASS");
         }
@@ -3468,3 +3469,26 @@ issue_4912_3: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5079: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        do {
+            (a = 123456).p = a;
+            a.q = null;
+        } while (console.log("PASS"));
+    }
+    expect: {
+        do {
+            0, 0, null;
+        } while (console.log("PASS"));
+    }
+    expect_stdout: "PASS"
+}

test/compress/evaluate.js

@@ -684,26 +684,47 @@ prototype_function: {
         side_effects: true,
     }
     input: {
-        var a = ({valueOf: 0}) < 1;
-        var b = ({toString: 0}) < 1;
-        var c = ({valueOf: 0}) + "";
-        var d = ({toString: 0}) + "";
-        var e = (({valueOf: 0}) + "")[2];
-        var f = (({toString: 0}) + "")[2];
-        var g = ({valueOf: 0}).valueOf();
-        var h = ({toString: 0}).toString();
+        function v() {
+            return this.valueOf === v ? "PASS" : "FAIL";
+        }
+        console.log(({ valueOf: v }) < 1);
+        console.log(({ valueOf: v }) + "");
+        console.log((( {valueOf: v }) + "")[2]);
+        console.log(({ valueOf: v }).valueOf());
+        function t() {
+            return this.toString === t ? "PASS" : "FAIL";
+        }
+        console.log(({ toString: t }) < 1);
+        console.log(({ toString: t }) + "");
+        console.log((( {toString: t }) + "")[2]);
+        console.log(({ toString: t }).toString());
     }
     expect: {
-        var a = ({valueOf: 0}) < 1;
-        var b = ({toString: 0}) < 1;
-        var c = ({valueOf: 0}) + "";
-        var d = ({toString: 0}) + "";
-        var e = (({valueOf: 0}) + "")[2];
-        var f = (({toString: 0}) + "")[2];
-        var g = 0();
-        var h = 0();
+        function v() {
+            return this.valueOf === v ? "PASS" : "FAIL";
+        }
+        console.log(({ valueOf: v }) < 1);
+        console.log(({ valueOf: v }) + "");
+        console.log((( {valueOf: v }) + "")[2]);
+        console.log(({ valueOf: v }).valueOf());
+        function t() {
+            return this.toString === t ? "PASS" : "FAIL";
+        }
+        console.log(({ toString: t }) < 1);
+        console.log(({ toString: t }) + "");
+        console.log((( {toString: t }) + "")[2]);
+        console.log(({ toString: t }).toString());
     }
-    expect_stdout: true
+    expect_stdout: [
+        "false",
+        "PASS",
+        "S",
+        "PASS",
+        "false",
+        "PASS",
+        "S",
+        "PASS",
+    ]
 }
 
 call_args: {

test/compress/exponentiation.js

@@ -99,8 +99,8 @@ issue_4664: {
     expect: {
         (function f() {
             new function(a) {
-                console.log(typeof f, 1073741824, typeof this);
-            }(A = 0);
+                console.log(typeof f, a, typeof this);
+            }((A = 0, 2 ** 30));
         })();
     }
     expect_stdout: "function 1073741824 object"

test/compress/exports.js

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

test/compress/functions.js

@@ -1171,11 +1171,11 @@ issue_2620_4: {
     }
     expect: {
         var c = "FAIL";
-        !function() {
+        (function() {
             switch (NaN) {
               case void (c = "PASS"):
             }
-        }();
+        })();
         console.log(c);
     }
     expect_stdout: "PASS"
@@ -2123,7 +2123,7 @@ issue_3016_2: {
 issue_3016_2_ie8: {
     options = {
         dead_code: true,
-        ie8: true,
+        ie: true,
         inline: true,
         toplevel: true,
     }
@@ -2188,7 +2188,7 @@ issue_3016_3: {
 issue_3016_3_ie8: {
     options = {
         dead_code: true,
-        ie8: true,
+        ie: true,
         inline: true,
         toplevel: true,
     }
@@ -2826,6 +2826,36 @@ functions_use_strict: {
     expect_stdout: "a true 42 function function function"
 }
 
+functions_cross_scope_reference: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        log = function(fn) {
+            console.log(typeof fn());
+        };
+        var a = function() {};
+        function f() {
+            return a;
+        }
+        while (log(f));
+    }
+    expect: {
+        log = function(fn) {
+            console.log(typeof fn());
+        };
+        function a() {}
+        function f() {
+            return a;
+        }
+        while (log(f));
+    }
+    expect_stdout: "function"
+}
+
 functions_inner_var: {
     options = {
         functions: true,
@@ -2905,6 +2935,7 @@ issue_2437: {
 issue_2485_1: {
     options = {
         functions: true,
+        passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
         unused: true,
@@ -2955,6 +2986,7 @@ issue_2485_2: {
     options = {
         functions: true,
         inline: true,
+        passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
         unused: true,
@@ -6283,3 +6315,343 @@ issue_5036: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5046: {
+    options = {
+        conditionals: true,
+        evaluate: true,
+        keep_fnames: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0;
+        if (a)
+            0();
+        else
+            (function f() {
+                f;
+                return a = "PASS";
+            })();
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        (a ? 0 : function f() {
+            return a = "PASS";
+        })();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5061_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var f, a = 1;
+        (f = function() {
+            console.log(a ? "foo" : "bar");
+        })();
+        f(a = 0);
+    }
+    expect: {
+        var f, a = 1;
+        (f = function() {
+            console.log(a ? "foo" : "bar");
+        })();
+        f(a = 0);
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_5061_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f, a = 1;
+        (f = function() {
+            console.log(a ? "foo" : "bar");
+        })();
+        f(a = 0);
+    }
+    expect: {
+        var f, a = 1;
+        (f = function() {
+            console.log(a ? "foo" : "bar");
+        })();
+        f(a = 0);
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+    ]
+}
+
+issue_5067: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var f = function() {
+            f();
+        };
+    }
+    expect: {}
+}
+
+issue_5096_1: {
+    options = {
+        evaluate: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b = "FAIL", c = 1;
+        do {
+            a && a();
+            a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect: {
+        var a, b = "FAIL", c = 1;
+        do {
+            a && a();
+            a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5096_2: {
+    options = {
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b = "FAIL", c = 1;
+        do {
+            a && a();
+            a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect: {
+        var a, b = "FAIL", c = 1;
+        do {
+            a && a();
+            a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5096_3: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var b = "FAIL", c = 1;
+        do {
+            a && a();
+            var a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect: {
+        var b = "FAIL", c = 1;
+        do {
+            a && a();
+            var a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5096_4: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var b = "FAIL", c = 1;
+        do {
+            a && a();
+            var a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect: {
+        var b = "FAIL", c = 1;
+        do {
+            a && a();
+            var a = function() {
+                b = "PASS";
+            };
+        } while (c--);
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5098: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(o) {
+            function f() {
+                f = console.log;
+                if (o.p++)
+                    throw "FAIL";
+                f("PASS");
+            }
+            return f;
+        })({ p: 0 })();
+    }
+    expect: {
+        (function(o) {
+            function f() {
+                f = console.log;
+                if (o.p++)
+                    throw "FAIL";
+                f("PASS");
+            }
+            return f;
+        })({ p: 0 })();
+    }
+    expect_stdout: "PASS"
+}
+
+shorter_without_void: {
+    options = {
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a;
+        function f(b) {
+            a = b;
+        }
+        f("foo");
+        console.log(a) || f("bar");
+        console.log(a, f("baz"));
+        console.log(a);
+    }
+    expect: {
+        var a;
+        function f(b) {
+            a = b;
+        }
+        a = "foo";
+        console.log(a) || (a = "bar");
+        console.log(a, f("baz"));
+        console.log(a);
+    }
+    expect_stdout: [
+        "foo",
+        "bar undefined",
+        "baz",
+    ]
+}
+
+issue_5120: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f() {
+            function g() {
+                f || g();
+            }
+            g();
+            return f.valueOf();
+        };
+        console.log(a() === a ? "PASS" : "FAIL");
+    }
+    expect: {
+        function a() {
+            (function g() {
+                a || g();
+            })();
+            return a.valueOf();
+        }
+        console.log(a() === a ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5140: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        A = 42;
+        function f(b) {
+            return b >> 0;
+        }
+        var a = f(42 in []);
+        console.log(f(A));
+    }
+    expect: {
+        function f(b) {
+            return b >> 0;
+        }
+        A = 42;
+        console.log(A >> 0);
+    }
+    expect_stdout: "42"
+}

test/compress/hoist_props.js

@@ -777,6 +777,32 @@ issue_3046: {
 }
 
 issue_3071_1: {
+    options = {
+        evaluate: true,
+        hoist_props: true,
+        inline: true,
+        join_vars: true,
+        passes: 3,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var obj = {};
+            obj.one = 1;
+            obj.two = 2;
+            console.log(obj.one, obj.two);
+        })();
+    }
+    expect: {
+        console.log(1, 2);
+    }
+    expect_stdout: "1 2"
+}
+
+issue_3071_1_toplevel: {
     options = {
         evaluate: true,
         hoist_props: true,
@@ -1094,3 +1120,24 @@ object_super: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4985: {
+    options = {
+        hoist_props: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = { p: 42 };
+        console.log(function() {
+            a;
+        }());
+    }
+    expect: {
+        var a_p = 42;
+        console.log(function() {
+            ({});
+        }());
+    }
+    expect_stdout: "undefined"
+}

test/compress/hoist_vars.js

@@ -152,7 +152,8 @@ issue_4487: {
     }
     expect: {
         function a() {
-            var f = console.log(typeof f);
+            var f;
+            console.log(typeof f);
         }
         a();
     }
@@ -322,9 +323,7 @@ issue_4893_1: {
     expect: {
         try{
             (function f() {
-                var b;
-                b = null;
-                b.p += 42;
+                null.p += 42;
                 f;
             })();
         } catch (e) {

test/compress/issue-1446.js

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

test/compress/issue-1588.js

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

test/compress/issue-1704.js

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

test/compress/issue-1733.js

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

test/compress/keep_fargs.js

@@ -951,7 +951,7 @@ function_name_mangle_ie8: {
         unused: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {

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

@@ -494,6 +494,41 @@ reduce_vars_3: {
     node_version: ">=4"
 }
 
+reduce_lambda: {
+    options = {
+        evaluate: true,
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        let f = function() {
+            console.log(a, b);
+        };
+        let a = "foo", b = 42;
+        f();
+        b = "bar";
+        f();
+    }
+    expect: {
+        "use strict";
+        function f() {
+            console.log("foo", b);
+        }
+        let b = 42;
+        f();
+        b = "bar";
+        f();
+    }
+    expect_stdout: [
+        "foo 42",
+        "foo bar",
+    ]
+    node_version: ">=4"
+}
+
 hoist_props: {
     options = {
         hoist_props: true,
@@ -1129,7 +1164,7 @@ issue_4225: {
 
 issue_4229: {
     options = {
-        ie8: true,
+        ie: true,
         side_effects: true,
     }
     input: {
@@ -1160,7 +1195,7 @@ issue_4229: {
 
 issue_4231: {
     options = {
-        ie8: true,
+        ie: true,
         side_effects: true,
     }
     input: {
@@ -1529,7 +1564,7 @@ issue_4438: {
 
 issue_4531_1: {
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {
@@ -1555,11 +1590,11 @@ issue_4531_1: {
 issue_4531_2: {
     options = {
         evaluate: true,
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     mangle = {
-        ie8: true,
+        ie: true,
         toplevel: true,
     }
     input: {

test/compress/loops.js

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

test/compress/merge_vars.js

@@ -359,7 +359,7 @@ issue_4107: {
 
 issue_4109: {
     options = {
-        ie8: true,
+        ie: true,
         merge_vars: true,
         toplevel: true,
     }
@@ -2735,8 +2735,7 @@ issue_4135: {
         0;
         a++;
         if (!a)
-            c = (a++, c = 0, void (c && c.p));
-        var c;
+            var c = void a++;
         console.log(a, -1, c);
     }
     expect_stdout: "1 -1 undefined"

test/compress/nullish.js

@@ -265,7 +265,7 @@ de_morgan_2e: {
 issue_4679: {
     options = {
         comparisons: true,
-        ie8: true,
+        ie: true,
     }
     input: {
         var a;

test/compress/optional-chains.js

@@ -58,7 +58,7 @@ assign_parentheses_dot: {
     input: {
         (console?.log).name.p = console.log("PASS");
     }
-    expect_exact: '(console?.log.name).p=console.log("PASS");'
+    expect_exact: '(console?.log).name.p=console.log("PASS");'
     expect_stdout: "PASS"
     node_version: ">=14"
 }
@@ -72,6 +72,26 @@ assign_no_parentheses: {
     node_version: ">=14"
 }
 
+call_parentheses: {
+    input: {
+        (function(o) {
+            console.log(o.f("FAIL"), (o.f)("FAIL"), (0, o.f)(42));
+            console.log(o?.f("FAIL"), (o?.f)("FAIL"), (0, o?.f)(42));
+        })({
+            a: "PASS",
+            f(b) {
+                return this.a || b;
+            },
+        });
+    }
+    expect_exact: '(function(o){console.log(o.f("FAIL"),o.f("FAIL"),(0,o.f)(42));console.log(o?.f("FAIL"),(o?.f)("FAIL"),(0,o?.f)(42))})({a:"PASS",f(b){return this.a||b}});'
+    expect_stdout: [
+        "PASS PASS 42",
+        "PASS PASS 42",
+    ]
+    node_version: ">=14"
+}
+
 unary_parentheses: {
     input: {
         var o = { p: 41 };
@@ -237,6 +257,99 @@ trim_2: {
     node_version: ">=14"
 }
 
+trim_dot_call_1: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+    }
+    input: {
+        console.log(null?.f());
+    }
+    expect: {
+        console.log(void 0);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+trim_dot_call_2: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+        unsafe: true,
+    }
+    input: {
+        try {
+            (null?.p)();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            (void 0)();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+trim_dot_call_3: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+        unsafe: true,
+    }
+    input: {
+        try {
+            ({ p: null })?.p();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            null();
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+trim_dot_sub: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+    }
+    input: {
+        console.log(null?.p[42]);
+    }
+    expect: {
+        console.log(void 0);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
+trim_sub_call_call: {
+    options = {
+        evaluate: true,
+        optional_chains: true,
+    }
+    input: {
+        console.log(null?.[42]()());
+    }
+    expect: {
+        console.log(void 0);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=14"
+}
+
 issue_4906: {
     options = {
         toplevel: true,
@@ -256,7 +369,7 @@ issue_4906: {
 
 issue_4928: {
     options = {
-        ie8: true,
+        ie: true,
         toplevel: true,
         unused: true,
     }
@@ -305,3 +418,51 @@ issue_4947_2: {
     expect_stdout: "PASS"
     node_version: ">=14"
 }
+
+issue_5039: {
+    options = {
+        ie: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = a?.[function f() {
+            f;
+            a;
+        }];
+        console.log("PASS");
+    }
+    expect: {
+        (function f() {});
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}
+
+issue_5091: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a) {
+            var b = a.p;
+            var c;
+            b?.[c = "FAIL 2"];
+            return b || c;
+        }
+        console.log(f("FAIL 1") || "PASS");
+    }
+    expect: {
+        function f(b) {
+            var b = b.p;
+            var c;
+            b?.[c = "FAIL 2"];
+            return b || c;
+        }
+        console.log(f("FAIL 1") || "PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=14"
+}

test/compress/properties.js

@@ -17,7 +17,7 @@ dot_properties: {
         properties: true,
     }
     beautify = {
-        ie8: true,
+        ie: true,
     }
     input: {
         a["foo"] = "bar";
@@ -43,7 +43,7 @@ dot_properties_es5: {
         properties: true,
     }
     beautify = {
-        ie8: false,
+        ie: false,
     }
     input: {
         a["foo"] = "bar";
@@ -1463,3 +1463,50 @@ issue_4888: {
     }
     expect_stdout: "object"
 }
+
+issue_5093: {
+    beautify = {
+        keep_quoted_props: true,
+    }
+    input: {
+        console.log({
+            a: true,
+            '42': "PASS",
+            "null": [],
+        }[6 * 7]);
+    }
+    expect_exact: 'console.log({a:true,"42":"PASS","null":[]}[6*7]);'
+    expect_stdout: "PASS"
+}
+
+issue_5093_quote_keys: {
+    beautify = {
+        keep_quoted_props: true,
+        quote_keys: true,
+    }
+    input: {
+        console.log({
+            a: true,
+            '42': "PASS",
+            "null": [],
+        }[6 * 7]);
+    }
+    expect_exact: 'console.log({"a":true,"42":"PASS","null":[]}[6*7]);'
+    expect_stdout: "PASS"
+}
+
+issue_5093_quote_style: {
+    beautify = {
+        keep_quoted_props: true,
+        quote_style: 3,
+    }
+    input: {
+        console.log({
+            a: true,
+            '42': "PASS",
+            "null": [],
+        }[6 * 7]);
+    }
+    expect_exact: 'console.log({a:true,\'42\':"PASS","null":[]}[6*7]);'
+    expect_stdout: "PASS"
+}

test/compress/pure_getters.js

@@ -1320,6 +1320,7 @@ issue_2878: {
 
 issue_3427: {
     options = {
+        assignments: true,
         evaluate: true,
         inline: true,
         pure_getters: "strict",

test/compress/reduce_vars.js

@@ -1292,6 +1292,7 @@ toplevel_on_loops_3: {
         loops: true,
         reduce_funcs: true,
         reduce_vars: true,
+        side_effects: true,
         toplevel: true,
         unused: true,
     }
@@ -3092,7 +3093,7 @@ accessor_1: {
                 a = 2;
                 return a;
             },
-            b: 1
+            b: 1,
         }.b, a);
     }
     expect: {
@@ -3102,7 +3103,7 @@ accessor_1: {
                 a = 2;
                 return a;
             },
-            b: 1
+            b: 1,
         }.b, a);
     }
     expect_stdout: "1 1"
@@ -3122,7 +3123,7 @@ accessor_2: {
         var B = {
             get c() {
                 console.log(A);
-            }
+            },
         };
         B.c;
     }
@@ -3130,7 +3131,7 @@ accessor_2: {
         ({
             get c() {
                 console.log(1);
-            }
+            },
         }).c;
     }
     expect_stdout: "1"
@@ -3176,7 +3177,7 @@ obj_var_1: {
         var obj = {
             bar: function() {
                 return C + C;
-            }
+            },
         };
         console.log(obj.bar());
     }
@@ -3184,7 +3185,7 @@ obj_var_1: {
         console.log({
             bar: function() {
                 return 2;
-            }
+            },
         }.bar());
     }
     expect_stdout: "2"
@@ -3208,7 +3209,7 @@ obj_var_2: {
         var obj = {
             bar: function() {
                 return C + C;
-            }
+            },
         };
         console.log(obj.bar());
     }
@@ -4422,6 +4423,7 @@ perf_2: {
 
 perf_3: {
     options = {
+        passes: 2,
         reduce_funcs: true,
         reduce_vars: true,
         toplevel: true,
@@ -4430,10 +4432,10 @@ perf_3: {
     input: {
         var foo = function(x, y, z) {
             return x < y ? x * y + z : x * z - y;
-        }
+        };
         var indirect_foo = function(x, y, z) {
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4462,10 +4464,10 @@ perf_4: {
     input: {
         var foo = function(x, y, z) {
             return x < y ? x * y + z : x * z - y;
-        }
+        };
         var indirect_foo = function(x, y, z) {
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4474,10 +4476,10 @@ perf_4: {
     expect: {
         var foo = function(x, y, z) {
             return x < y ? x * y + z : x * z - y;
-        }
+        };
         var indirect_foo = function(x, y, z) {
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4566,9 +4568,9 @@ perf_7: {
         var indirect_foo = function(x, y, z) {
             var foo = function(x, y, z) {
                 return x < y ? x * y + z : x * z - y;
-            }
+            };
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4598,9 +4600,9 @@ perf_8: {
         var indirect_foo = function(x, y, z) {
             var foo = function(x, y, z) {
                 return x < y ? x * y + z : x * z - y;
-            }
+            };
             return foo(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -4611,7 +4613,7 @@ perf_8: {
             return function(x, y, z) {
                 return x < y ? x * y + z : x * z - y;
             }(x, y, z);
-        }
+        };
         var sum = 0;
         for (var i = 0; i < 100; ++i)
             sum += indirect_foo(i, i + 1, 3 * i);
@@ -7676,3 +7678,97 @@ issue_4949: {
     }
     expect_stdout: "0 1"
 }
+
+issue_5048: {
+    options = {
+        reduce_funcs: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            var a = function() {
+                return a + 42;
+            };
+        }());
+    }
+    expect: {
+        console.log(function() {}());
+    }
+    expect_stdout: "undefined"
+}
+
+issue_5050: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        function f() {
+            console.log(a);
+        }
+        this;
+        var a = 1;
+        f(console.log(2), f(), a = 3);
+    }
+    expect: {
+        function f() {
+            console.log(a);
+        }
+        this;
+        var a = 1;
+        f(console.log(2), f(), a = 3);
+    }
+    expect_stdout: [
+        "2",
+        "1",
+        "3",
+    ]
+}
+
+issue_5055_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "PASS";
+        function f() {
+            console.log(a || "FAIL");
+        }
+        f(0 && (a = 0)(f(this)));
+    }
+    expect: {
+        var a = "PASS";
+        function f() {
+            console.log(a || "FAIL");
+        }
+        f(0);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5055_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        function f() {
+            console.log(a || "FAIL");
+        }
+        f(0 && (a = 0)(f(this)));
+    }
+    expect: {
+        var a = "PASS";
+        function f() {
+            console.log(a || "FAIL");
+        }
+        f(0 && (a = 0)(f()));
+    }
+    expect_stdout: "PASS"
+}

test/compress/rename.js

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

test/compress/rests.js

@@ -244,7 +244,7 @@ retain_destructured_array: {
         console.log.apply(console, b);
     }
     expect: {
-        var [ , ...b ] = [ "FAIL", "PASS", 42 ];
+        var [ ...b ] = [ "PASS", 42 ];
         console.log.apply(console, b);
     }
     expect_stdout: "PASS 42"
@@ -284,7 +284,7 @@ retain_destructured_object_2: {
             console.log(k, b[k]);
     }
     expect: {
-        var { foo: [], ...b } = { foo: [ "FAIL" ], bar: "PASS", baz: 42 };
+        var { foo: {}, ...b } = { foo: 0, bar: "PASS", baz: 42 };
         for (var k in b)
             console.log(k, b[k]);
     }
@@ -407,6 +407,24 @@ drop_unused_call_args_2: {
     node_version: ">=6"
 }
 
+maintain_position: {
+    options = {
+        unused: true,
+    }
+    input: {
+        A = "FAIL";
+        var [ , ...a ] = [ A, "PASS" ];
+        console.log(a[0]);
+    }
+    expect: {
+        A = "FAIL";
+        var [ , ...a ] = [ A, "PASS" ];
+        console.log(a[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 merge_funarg: {
     options = {
         merge_vars: true,
@@ -491,7 +509,7 @@ drop_rest_array: {
         rests: true,
     }
     input: {
-        var [ ...[ a ]] = [ "PASS" ];
+        var [ ...[ a ] ] = [ "PASS" ];
         console.log(a);
     }
     expect: {
@@ -542,6 +560,100 @@ drop_rest_lambda: {
     node_version: ">=6"
 }
 
+keep_rest_array: {
+    options = {
+        rests: true,
+    }
+    input: {
+        var [ ...[ ...a ] ] = "PASS";
+        console.log(a.join(""));
+    }
+    expect: {
+        var [ ...a ] = "PASS";
+        console.log(a.join(""));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_rest_arrow: {
+    options = {
+        arrows: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        rests: true,
+    }
+    input: {
+        console.log(((...[ ...a ]) => a.join(""))("PASS"));
+    }
+    expect: {
+        console.log(((...a) => a.join(""))("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+keep_rest_lambda_1: {
+    options = {
+        keep_fargs: false,
+        reduce_vars: true,
+        rests: true,
+        toplevel: true,
+    }
+    input: {
+        function f(...[ ...a ]) {
+            return a.join("");
+        }
+        console.log(f("PASS"), f([ 42 ]));
+    }
+    expect: {
+        function f(...a) {
+            return a.join("");
+        }
+        console.log(f("PASS"), f([ 42 ]));
+    }
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+keep_rest_lambda_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        function f(...[ ...a ]) {
+            return a.join("");
+        }
+        console.log(f("PASS"), f([ 42 ]));
+    }
+    expect: {
+        function f(...[ ...a ]) {
+            return a.join("");
+        }
+        console.log(f("PASS"), f([ 42 ]));
+    }
+    expect_stdout: "PASS 42"
+    node_version: ">=6"
+}
+
+drop_new_function: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        new function(...{
+            [console.log("PASS")]: a,
+        }) {}();
+    }
+    expect: {
+        void ([ ... {
+            [console.log("PASS")]: [].e,
+        }] = []);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 issue_4525_1: {
     options = {
         arguments: true,
@@ -647,6 +759,78 @@ issue_4544_2: {
     node_version: ">=6"
 }
 
+issue_4560_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0;
+        (function(...{
+            [a++]: {},
+        }) {})(2);
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        (function(...{
+            [a++]: {},
+        }) {})(2);
+        console.log(a);
+    }
+    expect_stdout: "1"
+    node_version: ">=6"
+}
+
+issue_4560_2: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 0;
+        (function(...{
+            [a++]: {},
+        }) {})(2);
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        (function(...{
+            [a++]: {},
+        }) {})(2);
+        console.log(a);
+    }
+    expect_stdout: "1"
+    node_version: ">=6"
+}
+
+issue_4560_3: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0, b;
+        [ ...{
+            [a++]: b,
+        } ] = [ "PASS" ];
+        console.log(b);
+    }
+    expect: {
+        var a = 0, b;
+        [ ...{
+            [a++]: b,
+        } ] = [ "PASS" ];
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
 issue_4562: {
     options = {
         evaluate: true,
@@ -667,7 +851,7 @@ issue_4562: {
 issue_4575: {
     options = {
         collapse_vars: true,
-        ie8: true,
+        ie: true,
         reduce_vars: true,
         rests: true,
         unused: true,
@@ -777,10 +961,193 @@ issue_4666: {
     expect: {
         var a = 0, b = 0;
         var o = (c => +a + c)([ b ]);
-        for(var k in o)
+        for (var k in o)
             b++;
         console.log(1, b);
     }
     expect_stdout: "1 2"
     node_version: ">=6"
 }
+
+issue_5089_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var {
+            p: [] = 42,
+            ...o
+        } = {
+            p: [],
+        };
+        console.log(o.p);
+    }
+    expect: {
+        var {
+            p: {},
+            ...o
+        } = {
+            p: 0,
+        };
+        console.log(o.p);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=8"
+}
+
+issue_5089_2: {
+    options = {
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        var {
+            p: {} = null,
+            ...o
+        } = {
+            p: {},
+        };
+        console.log(o.p);
+    }
+    expect: {
+        var {
+            p: {},
+            ...o
+        } = {
+            p: 0,
+        };
+        console.log(o.p);
+    }
+    expect_stdout: "undefined"
+    node_version: ">=8"
+}
+
+issue_5100_1: {
+    options = {
+        passes: 2,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        [ {
+            p: {},
+            ...a
+        } ] = [ {
+            p: {
+                q: a,
+            } = 42,
+            r: "PASS",
+        } ];
+        console.log(a.r);
+    }
+    expect: {
+        var a;
+        [ {
+            p: {},
+            ...a
+        } ] = [ {
+            p: [ a = 42["q"] ],
+            r: "PASS",
+        } ];
+        console.log(a.r);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8"
+}
+
+issue_5100_2: {
+    options = {
+        passes: 2,
+        pure_getters: "strict",
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        [ {
+            p: {},
+            ...a
+        } ] = [ {
+            p: (console.log("PASS"), {
+                q: a,
+            } = 42),
+        } ];
+    }
+    expect: {
+        var a;
+        [ {
+            p: {},
+            ...a
+        } ] = [ {
+            p: [ console.log("PASS"), a = 42["q"] ],
+        } ];
+    }
+    expect_stdout: "PASS"
+    node_version: ">=10"
+}
+
+issue_5108: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        rests: true,
+        unsafe: true,
+        unused: true,
+    }
+    input: {
+        console.log(function([ ...[ a ] ]) {
+            return a;
+        }([ "PASS", "FAIL" ]));
+    }
+    expect: {
+        console.log(function([]) {
+            return "PASS";
+        }([ "PASS", "FAIL" ]));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5128_1: {
+    options = {
+        inline: true,
+    }
+    input: {
+        console.log(function() {
+            return function f(...[ a ]) {
+                return a;
+            }("PASS");
+        }());
+    }
+    expect: {
+        console.log(function f(...[ a ]) {
+            return a;
+        }("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5128_2: {
+    options = {
+        inline: true,
+        keep_fnames: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            return function f(...[ a ]) {
+                return a;
+            }("PASS");
+        }());
+    }
+    expect: {
+        console.log(function f(...[ a ]) {
+            return a;
+        }("PASS"));
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/compress/spreads.js

@@ -945,78 +945,6 @@ issue_4556: {
     node_version: ">=6"
 }
 
-issue_4560_1: {
-    options = {
-        evaluate: true,
-        reduce_vars: true,
-        toplevel: true,
-    }
-    input: {
-        var a = 0;
-        (function(...{
-            [a++]: {},
-        }) {})(2);
-        console.log(a);
-    }
-    expect: {
-        var a = 0;
-        (function(...{
-            [a++]: {},
-        }) {})(2);
-        console.log(a);
-    }
-    expect_stdout: "1"
-    node_version: ">=6"
-}
-
-issue_4560_2: {
-    options = {
-        reduce_vars: true,
-        toplevel: true,
-        unused: true,
-    }
-    input: {
-        var a = 0;
-        (function(...{
-            [a++]: {},
-        }) {})(2);
-        console.log(a);
-    }
-    expect: {
-        var a = 0;
-        (function(...{
-            [a++]: {},
-        }) {})(2);
-        console.log(a);
-    }
-    expect_stdout: "1"
-    node_version: ">=6"
-}
-
-issue_4560_3: {
-    options = {
-        collapse_vars: true,
-        reduce_vars: true,
-        toplevel: true,
-    }
-    input: {
-        var a = 0, b;
-        [ ...{
-            [a++]: b,
-        } ] = [ "PASS" ];
-        console.log(b);
-    }
-    expect: {
-        var a = 0, b;
-        [ ...{
-            [a++]: b,
-        } ] = [ "PASS" ];
-        console.log(b);
-    }
-    expect_stdout: "PASS"
-    node_version: ">=6"
-}
-
 issue_4614: {
     options = {
         pure_getters: "strict",

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"
@@ -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 +534,212 @@ 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"
+}

test/compress/transform.js

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

test/compress/webkit.js

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

test/compress/yields.js

@@ -1246,3 +1246,32 @@ issue_5034: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_5076: {
+    options = {
+        evaluate: true,
+        hoist_vars: true,
+        passes: 2,
+        pure_getters: "strict",
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+        yields: true,
+    }
+    input: {
+        var a;
+        console.log("PASS");
+        var b = function*({
+            p: {},
+        }) {}({
+            p: { a } = 42,
+        });
+    }
+    expect: {
+        var a;
+        console.log("PASS");
+        a = 42["a"];
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}

test/input/invalid/optional-template.js

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

test/input/reduce/diff_error.reduced.js

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

test/jetstream.js

@@ -68,6 +68,7 @@ if (typeof phantom == "undefined") {
         (function install() {
             npm([
                 "install",
+                "graceful-fs@4.2.6",
                 "phantomjs-prebuilt@2.1.14",
                 "--no-audit",
                 "--no-optional",

test/mocha/cli.js

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

test/mocha/comments.js

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

test/mocha/glob.js

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

test/mocha/ie8.js

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

test/mocha/let.js

@@ -1,5 +1,5 @@
 var assert = require("assert");
-var UglifyJS = require("../..");
+var UglifyJS = require("../node");
 
 describe("let", function() {
     this.timeout(30000);
@@ -41,7 +41,7 @@ describe("let", function() {
         }
         var result = UglifyJS.minify(s, {
             compress: false,
-            ie8: true,
+            ie: true,
             mangle: {
                 properties: true,
             }
@@ -54,4 +54,43 @@ describe("let", function() {
             assert.notStrictEqual(result.indexOf('v["' + name + '"]'), -1);
         });
     });
+    it("Should parse `let` as name correctly", function() {
+        [
+            "for(var let;let;let)let;",
+            "function let(let){let}",
+        ].forEach(function(code) {
+            var ast = UglifyJS.parse(code);
+            assert.strictEqual(ast.print_to_string(), code);
+            assert.throws(function() {
+                UglifyJS.parse('"use strict";' + code);
+            }, function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error && e.message == "Unexpected let in strict mode";
+            }, code);
+        });
+    });
+    it("Should throw on ambiguous use of `let`", function() {
+        [
+            "export let",
+            [
+                "let",
+                "console.log(42)",
+            ].join("\n"),
+            [
+                "let",
+                "[ console.log(42) ]",
+            ].join("\n"),
+            [
+                "let",
+                "{",
+                "    console.log(42)",
+                "}",
+            ].join("\n"),
+        ].forEach(function(code) {
+            assert.throws(function() {
+                UglifyJS.parse(code);
+            }, function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error;
+            }, code);
+        });
+    });
 });

test/mocha/minify.js

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

test/mocha/reduce.js

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

test/mocha/sourcemaps.js

@@ -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/string-literal.js

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

test/mocha/templates.js

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

test/reduce.js

@@ -22,7 +22,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
     reduce_options = reduce_options || {};
     var print_options = {};
     [
-        "ie8",
+        "ie",
         "v8",
         "webkit",
     ].forEach(function(name) {
@@ -215,9 +215,9 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     // hoist and return expressions from the IIFE function expression
                     var seq = [];
                     node.expression.body.forEach(function(node) {
-                        var expr = expr instanceof U.AST_Exit ? node.value : node.body;
+                        var expr = node instanceof U.AST_Exit ? node.value : node.body;
                         if (expr instanceof U.AST_Node && !U.is_statement(expr) && can_hoist(expr)) {
-                            // collect expressions from each statements' body
+                            // collect expressions from each statement's body
                             seq.push(expr);
                         }
                     });
@@ -395,7 +395,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 var expr = [
                     node.expression,                         // switch expression
                     node.body[0] && node.body[0].expression, // first case expression or undefined
-                    node.body[0] && node.body[0],            // first case body or undefined
+                    node.body[0],                            // first case body or undefined
                 ][ (node.start._permute * steps | 0) % 4 ];
                 node.start._permute += step;
                 if (expr && (!(expr instanceof U.AST_Statement) || !has_loopcontrol(expr, node, parent))) {
@@ -726,7 +726,7 @@ function to_statement_init(node) {
     return node instanceof U.AST_Const || node instanceof U.AST_Let ? new U.AST_BlockStatement({
         body: [ node ],
         start: {},
-    }) : to_statement(node);;
+    }) : to_statement(node);
 }
 
 function wrap_with_console_log(node) {

test/sandbox.js

@@ -28,7 +28,7 @@ exports.run_code = semver.satisfies(process.version, "0.8") ? function(code, top
     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]*#|[ \t]*\*[ \t]*)[^\s()[\]{}#,.&|!~=*%/+-]+(\s*\(|[ \t]*=>)/,
     ].some(function(pattern) {
         return pattern.test(code);
     })) {
@@ -51,13 +51,13 @@ exports.same_stdout = semver.satisfies(process.version, "0.12") ? function(expec
 };
 exports.patch_module_statements = function(code) {
     var count = 0, imports = [];
-    code = code.replace(/\bexport(?:\s*\{[^}]*}\s*?(?:$|\n|;)|\s+default\b(?:\s*(\(|\{|class\s*\{|class\s+(?=extends\b)|(?:async\s+)?function\s*(?:\*\s*)?\())?|\b)/g, function(match, header) {
+    code = code.replace(/\bexport(?:\s*\{[^{}]*}\s*?(?:$|\n|;)|\s+default\b(?:\s*(\(|\{|class\s*\{|class\s+(?=extends\b)|(?:async\s+)?function\s*(?:\*\s*)?\())?|\b)/g, function(match, header) {
         if (!header) return "";
         if (header.length == 1) return "0, " + header;
         return header.slice(0, -1) + " _" + ++count + header.slice(-1);
     }).replace(/\bimport\.meta\b/g, function() {
         return '({ url: "https://example.com/path/index.html" })';
-    }).replace(/\bimport\b(?:\s*([^('"]+)\bfrom\b)?\s*(['"]).*?\2(?:$|\n|;)/g, function(match, symbols) {
+    }).replace(/\bimport\b(?:\s*([^\s('"][^('"]*)\bfrom\b)?\s*(['"]).*?\2(?:$|\n|;)/g, function(match, symbols) {
         if (symbols) {
             if (!/^[{*]/.test(symbols)) symbols = "default:" + symbols;
             symbols = symbols.replace(/[{}]/g, "").trim().replace(/\s*,\s*/g, ",");
@@ -278,11 +278,11 @@ function run_code_exec(code, toplevel, timeout) {
         timeout: timeout || 5000,
     });
     if (result.status === 0) return result.stdout;
+    var msg = ("" + result.stderr).replace(/\r\n/g, "\n");
     if (result.error && result.error.code == "ETIMEDOUT" || /FATAL ERROR:/.test(msg)) {
         return new Error("Script execution timed out.");
     }
     if (result.error) return result.error;
-    var msg = result.stderr.replace(/\r\n/g, "\n");
     var end = msg.indexOf("\n\n-----===== UNCAUGHT EXCEPTION =====-----\n\n");
     var details;
     if (end >= 0) {

test/ufuzz/index.js

@@ -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;
@@ -2027,6 +2028,7 @@ function removeAvoidVar(name) {
 function isBannedKeyword(name) {
     switch (name) {
       case "arguments":
+      case "let":
         return in_class;
       case "await":
         return async !== false;
@@ -2078,8 +2080,8 @@ 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) {
@@ -2256,7 +2258,7 @@ function sort_globals(code) {
             return (typeof global[n] == "function") - (typeof global[m] == "function")
                 || (m < n ? -1 : m > n ? 1 : 0);
         };
-    } + "(this));" + code);
+    } + "(this));\n" + code);
     if (!Array.isArray(globals)) {
         errorln();
         errorln();
@@ -2294,6 +2296,20 @@ function fuzzy_match(original, uglified) {
     }
 }
 
+function patch_proto() {
+    [ Array, Boolean, Error, Function, Number, Object, RegExp, String ].forEach(function(type) {
+        [ "toString", "valueOf" ].forEach(function(prop) {
+            type.prototype[prop] = function(fn) {
+                return function() {
+                    try {
+                        return fn.apply(this, arguments);
+                    } catch (e) {}
+                };
+            }(type.prototype[prop]);
+        });
+    });
+}
+
 function is_error_timeout(ex) {
     return /timed out/.test(ex.message);
 }
@@ -2336,7 +2352,7 @@ function patch_try_catch(orig, toplevel) {
         tries: [],
     } ];
     var tail_throw = '\nif (typeof UFUZZ_ERROR == "object") throw UFUZZ_ERROR;\n';
-    var re = /(?:(?:^|[\s{}):;])try|}\s*catch\s*\(([^)[{]+)\)|}\s*finally)\s*(?={)/g;
+    var re = /(?:(?:^|[\s{}):;])try|}\s*catch\s*\(([^()[{]+)\)|}\s*finally)\s*(?={)/g;
     while (stack.length) {
         var code = stack[0].code;
         var offset = stack[0].offset;
@@ -2500,8 +2516,8 @@ for (var round = 1; round <= num_iterations; round++) {
             if (!ok && errored && uglify_result.name == "ReferenceError" && original_result.name == "ReferenceError") ok = true;
             // ignore difference due to implicit strict-mode in `class`
             if (!ok && /\bclass\b/.test(original_code)) {
-                var original_strict = run_code('"use strict";' + original_code, toplevel);
-                var uglify_strict = run_code('"use strict";' + uglify_code, toplevel);
+                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";
                 } else {
@@ -2512,6 +2528,12 @@ for (var round = 1; round <= num_iterations; round++) {
             if (!ok && errored && /\bimport\b/.test(original_code)) {
                 if (is_error_redeclaration(uglify_result) && is_error_redeclaration(original_result)) ok = true;
             }
+            // ignore difference due to `__proto__` assignment
+            if (!ok && /\b__proto__\b/.test(original_code)) {
+                var original_proto = run_code("(" + patch_proto + ")();\n" + original_code, toplevel);
+                var uglify_proto = run_code("(" + patch_proto + ")();\n" + uglify_code, toplevel);
+                ok = sandbox.same_stdout(original_proto, uglify_proto);
+            }
             // ignore difference in error message caused by `in`
             if (!ok && errored && is_error_in(uglify_result) && is_error_in(original_result)) ok = true;
             // ignore difference in error message caused by spread syntax

test/ufuzz/options.json

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