v3.12.0

workaround Safari quirks (#4314 )
fixes #1753
2020-11-23 01:10:39 +08:00 · 2020-11-21 10:30:46 +08:00 · 2020-11-21 08:57:59 +08:00 · 2020-11-21 08:05:40 +08:00 · 2020-11-21 03:37:33 +08:00 · 2020-11-20 06:23:37 +08:00
34 changed files with 4746 additions and 704 deletions
--- a/README.md
+++ b/README.md
@@ -135,6 +135,10 @@ a double dash to prevent input files being used as option arguments:
    --toplevel                  Compress and/or mangle variables in top level scope.
    --verbose                   Print diagnostic messages.
    --warn                      Print warning messages.
+    --webkit                    Support non-standard Safari/Webkit.
+                                Equivalent to setting `webkit: true` in `minify()`
+                                for `mangle` and `output` options.
+                                By default UglifyJS will not try to be Safari-proof.
    --wrap <name>               Embed everything in a big function, making the
                                “exports” and “global” variables available. You
                                need to pass an argument to this option to
@@ -519,6 +523,9 @@ if (result.error) throw result.error;
 - `warnings` (default `false`) — pass `true` to return compressor warnings
  in `result.warnings`. Use the value `"verbose"` for more detailed warnings.

+- `webkit` (default `false`) -- enable workarounds for Safari/WebKit bugs.
+  PhantomJS users should set this option to `true`.
+
 ## Minify options structure

 ```javascript
@@ -868,6 +875,8 @@ can pass additional arguments that control the code output:
  }
  ```

+- `galio` (default `false`) -- enable workarounds for ANT Galio bugs
+
 - `indent_level` (default `4`)

 - `indent_start` (default `0`) -- prefix all lines by that many spaces
@@ -906,8 +915,7 @@ can pass additional arguments that control the code output:

 - `shebang` (default `true`) -- preserve shebang `#!` in preamble (bash scripts)

- `webkit` (default `false`) -- enable workarounds for WebKit bugs.
-  PhantomJS users should set this option to `true`.
+- `v8` (default `false`) -- enable workarounds for Chrome & Node.js bugs

 - `width` (default `80`) -- only takes effect when beautification is on, this
  specifies an (orientative) line width that the beautifier will try to
@@ -1138,7 +1146,7 @@ To enable fast minify mode with the API use:
 UglifyJS.minify(code, { compress: false, mangle: true });
 ```

-#### Source maps and debugging
+### Source maps and debugging

 Various `compress` transforms that simplify, rearrange, inline and remove code
 are known to have an adverse effect on debugging with source maps. This is
@@ -1150,6 +1158,10 @@ disable the Uglify `compress` option and just use `mangle`.

 To allow for better optimizations, the compiler makes various assumptions:

+- The code does not rely on preserving its runtime performance characteristics.
+  Typically uglified code will run faster due to less instructions and easier
+  inlining, but may be slower on rare occasions for a specific platform, e.g.
+  see [`reduce_funcs`](#compress-options).
 - `.toString()` and `.valueOf()` don't have side effects, and for built-in
  objects they have not been overridden.
 - `undefined`, `NaN` and `Infinity` have not been externally redefined.
@@ -1177,3 +1189,7 @@ To allow for better optimizations, the compiler makes various assumptions:
  top.B = "PASS";
  console.log(B);
  ```
+- Use of `arguments` alongside destructuring as function parameters, e.g.
+  `function({}, arguments) {}` will result in `SyntaxError` in earlier versions
+  of Chrome and Node.js - UglifyJS may modify the input which in turn may
+  suppress those errors.
--- a/bin/uglifyjs
+++ b/bin/uglifyjs
@@ -111,6 +111,7 @@ function process_option(name, no_value) {
                "  --validate                               Perform validation during AST manipulations.",
                "  --verbose                                Print diagnostic messages.",
                "  --warn                                   Print warning messages.",
+                "  --webkit                                 Support non-standard Safari/Webkit.",
                "  --wrap <name>                            Embed everything as a function with “exports” corresponding to “name” globally.",
                "  --reduce-test                            Reduce a standalone test case (assumes cloned repository).",
            ].join("\n"));
@@ -142,6 +143,7 @@ function process_option(name, no_value) {
      case "timings":
      case "toplevel":
      case "validate":
+      case "webkit":
        options[name] = true;
        break;
      case "keep-fnames":
@@ -276,7 +278,9 @@ function convert_ast(fn) {
 function run() {
    var content = options.sourceMap && options.sourceMap.content;
    if (content && content != "inline") {
-        UglifyJS.AST_Node.info("Using input source map: " + content);
+        UglifyJS.AST_Node.info("Using input source map: {content}", {
+            content : content,
+        });
        options.sourceMap.content = read_file(content, content);
    }
    try {
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -137,17 +137,17 @@ var AST_Node = DEFNODE("Node", "start end", {
 }, null);

 (AST_Node.log_function = function(fn, verbose) {
-    var printed = Object.create(null);
-    if (fn) {
-        AST_Node.info = verbose ? function(text, props) {
-            log("INFO: " + string_template(text, props));
-        } : noop;
-        AST_Node.warn = function(text, props) {
-            log("WARN: " + string_template(text, props));
-        };
-    } else {
+    if (!fn) {
        AST_Node.info = AST_Node.warn = noop;
+        return;
    }
+    var printed = Object.create(null);
+    AST_Node.info = verbose ? function(text, props) {
+        log("INFO: " + string_template(text, props));
+    } : noop;
+    AST_Node.warn = function(text, props) {
+        log("WARN: " + string_template(text, props));
+    };

    function log(msg) {
        if (printed[msg]) return;
@@ -414,8 +414,12 @@ var AST_ForIn = DEFNODE("ForIn", "init object", {
    _validate: function() {
        if (this.init instanceof AST_Definitions) {
            if (this.init.definitions.length != 1) throw new Error("init must have single declaration");
-        } else if (!(this.init instanceof AST_PropAccess || this.init instanceof AST_SymbolRef)) {
-            throw new Error("init must be assignable");
+        } else {
+            validate_destructured(this.init, function(node) {
+                if (!(node instanceof AST_PropAccess || node instanceof AST_SymbolRef)) {
+                    throw new Error("init must be assignable: " + node.TYPE);
+                }
+            });
        }
        must_be_expression(this, "object");
    },
@@ -496,12 +500,24 @@ var AST_Toplevel = DEFNODE("Toplevel", "globals", {
    }
 }, AST_Scope);

-var AST_Lambda = DEFNODE("Lambda", "name argnames uses_arguments length_read", {
+var AST_Lambda = DEFNODE("Lambda", "name argnames length_read uses_arguments", {
    $documentation: "Base class for functions",
    $propdoc: {
        name: "[AST_SymbolDeclaration?] the name of this function",
-        argnames: "[AST_SymbolFunarg*] array of function arguments",
-        uses_arguments: "[boolean/S] tells whether this function accesses the arguments array"
+        argnames: "[(AST_Destructured|AST_SymbolFunarg)*] array of function arguments and/or destructured literals",
+        uses_arguments: "[boolean/S] tells whether this function accesses the arguments array",
+    },
+    each_argname: function(visit) {
+        var tw = new TreeWalker(function(node) {
+            if (node instanceof AST_DestructuredKeyVal) {
+                node.value.walk(tw);
+                return true;
+            }
+            if (node instanceof AST_SymbolFunarg) visit(node);
+        });
+        this.argnames.forEach(function(argname) {
+            argname.walk(tw);
+        });
    },
    walk: function(visitor) {
        var node = this;
@@ -515,7 +531,9 @@ var AST_Lambda = DEFNODE("Lambda", "name argnames uses_arguments length_read", {
    },
    _validate: function() {
        this.argnames.forEach(function(node) {
-            if (!(node instanceof AST_SymbolFunarg)) throw new Error("argnames must be AST_SymbolFunarg[]");
+            validate_destructured(node, function(node) {
+                if (!(node instanceof AST_SymbolFunarg)) throw new Error("argnames must be AST_SymbolFunarg[]");
+            });
        });
    },
 }, AST_Scope);
@@ -748,8 +766,10 @@ var AST_Const = DEFNODE("Const", null, {
    _validate: function() {
        this.definitions.forEach(function(node) {
            if (!(node instanceof AST_VarDef)) throw new Error("definitions must be AST_VarDef[]");
-            if (!(node.name instanceof AST_SymbolConst)) throw new Error("name must be AST_SymbolConst");
-            must_be_expression(node, "value");
+            validate_destructured(node.name, function(node) {
+                if (!(node instanceof AST_SymbolConst)) throw new Error("name must be AST_SymbolConst");
+            });
+            if (node.value != null) must_be_expression(node, "value");
        });
    },
 }, AST_Definitions);
@@ -759,7 +779,9 @@ var AST_Let = DEFNODE("Let", null, {
    _validate: function() {
        this.definitions.forEach(function(node) {
            if (!(node instanceof AST_VarDef)) throw new Error("definitions must be AST_VarDef[]");
-            if (!(node.name instanceof AST_SymbolLet)) throw new Error("name must be AST_SymbolLet");
+            validate_destructured(node.name, function(node) {
+                if (!(node instanceof AST_SymbolLet)) throw new Error("name must be AST_SymbolLet");
+            });
            if (node.value != null) must_be_expression(node, "value");
        });
    },
@@ -770,7 +792,9 @@ var AST_Var = DEFNODE("Var", null, {
    _validate: function() {
        this.definitions.forEach(function(node) {
            if (!(node instanceof AST_VarDef)) throw new Error("definitions must be AST_VarDef[]");
-            if (!(node.name instanceof AST_SymbolVar)) throw new Error("name must be AST_SymbolVar");
+            validate_destructured(node.name, function(node) {
+                if (!(node instanceof AST_SymbolVar)) throw new Error("name must be AST_SymbolVar");
+            });
            if (node.value != null) must_be_expression(node, "value");
        });
    },
@@ -969,6 +993,14 @@ var AST_Assign = DEFNODE("Assign", null, {
    $documentation: "An assignment expression — `a = b + 5`",
    _validate: function() {
        if (this.operator.indexOf("=") < 0) throw new Error('operator must contain "="');
+        if (this.left instanceof AST_Destructured) {
+            if (this.operator != "=") throw new Error("invalid destructuring operator: " + this.operator);
+            validate_destructured(this.left, function(node) {
+                if (!(node instanceof AST_PropAccess || node instanceof AST_SymbolRef)) {
+                    throw new Error("left must be assignable: " + node.TYPE);
+                }
+            });
+        }
    },
 }, AST_Binary);

@@ -992,6 +1024,77 @@ var AST_Array = DEFNODE("Array", "elements", {
    },
 });

+var AST_Destructured = DEFNODE("Destructured", null, {
+    $documentation: "Base class for destructured literal",
+});
+
+function validate_destructured(node, check) {
+    if (node instanceof AST_DestructuredArray) return node.elements.forEach(function(node) {
+        if (!(node instanceof AST_Hole)) validate_destructured(node, check);
+    });
+    if (node instanceof AST_DestructuredObject) return node.properties.forEach(function(prop) {
+        validate_destructured(prop.value, check);
+    });
+    check(node);
+}
+
+var AST_DestructuredArray = DEFNODE("DestructuredArray", "elements", {
+    $documentation: "A destructured array literal",
+    $propdoc: {
+        elements: "[AST_Node*] array of elements",
+    },
+    walk: function(visitor) {
+        var node = this;
+        visitor.visit(node, function() {
+            node.elements.forEach(function(element) {
+                element.walk(visitor);
+            });
+        });
+    },
+}, AST_Destructured);
+
+var AST_DestructuredKeyVal = DEFNODE("DestructuredKeyVal", "key value", {
+    $documentation: "A key: value destructured property",
+    $propdoc: {
+        key: "[string|AST_Node] property name.  For computed property this is an AST_Node.",
+        value: "[AST_Node] property value",
+    },
+    walk: function(visitor) {
+        var node = this;
+        visitor.visit(node, function() {
+            if (node.key instanceof AST_Node) node.key.walk(visitor);
+            node.value.walk(visitor);
+        });
+    },
+    _validate: function() {
+        if (typeof this.key != "string") {
+            if (!(this.key instanceof AST_Node)) throw new Error("key must be string or AST_Node");
+            must_be_expression(this, "key");
+        }
+        must_be_expression(this, "value");
+    },
+});
+
+var AST_DestructuredObject = DEFNODE("DestructuredObject", "properties", {
+    $documentation: "A destructured object literal",
+    $propdoc: {
+        properties: "[AST_DestructuredKeyVal*] array of properties",
+    },
+    walk: function(visitor) {
+        var node = this;
+        visitor.visit(node, function() {
+            node.properties.forEach(function(prop) {
+                prop.walk(visitor);
+            });
+        });
+    },
+    _validate: function() {
+        this.properties.forEach(function(node) {
+            if (!(node instanceof AST_DestructuredKeyVal)) throw new Error("properties must be AST_DestructuredKeyVal[]");
+        });
+    },
+}, AST_Destructured);
+
 var AST_Object = DEFNODE("Object", "properties", {
    $documentation: "An object literal",
    $propdoc: {
@@ -1015,24 +1118,28 @@ var AST_Object = DEFNODE("Object", "properties", {
 var AST_ObjectProperty = DEFNODE("ObjectProperty", "key value", {
    $documentation: "Base class for literal object properties",
    $propdoc: {
-        key: "[string|AST_SymbolAccessor] property name. For ObjectKeyVal this is a string. For getters and setters this is an AST_SymbolAccessor.",
-        value: "[AST_Node] property value.  For getters and setters this is an AST_Accessor."
+        key: "[string|AST_Node] property name.  For computed property this is an AST_Node.",
+        value: "[AST_Node] property value.  For getters and setters this is an AST_Accessor.",
    },
    walk: function(visitor) {
        var node = this;
        visitor.visit(node, function() {
+            if (node.key instanceof AST_Node) node.key.walk(visitor);
            node.value.walk(visitor);
        });
-    }
-});
-
-var AST_ObjectKeyVal = DEFNODE("ObjectKeyVal", "quote", {
-    $documentation: "A key: value object property",
-    $propdoc: {
-        quote: "[string] the original quote character"
    },
    _validate: function() {
-        if (typeof this.key != "string") throw new Error("key must be string");
+        if (typeof this.key != "string") {
+            if (!(this.key instanceof AST_Node)) throw new Error("key must be string or AST_Node");
+            must_be_expression(this, "key");
+        }
+        if (!(this.value instanceof AST_Node)) throw new Error("value must be AST_Node");
+    },
+});
+
+var AST_ObjectKeyVal = DEFNODE("ObjectKeyVal", null, {
+    $documentation: "A key: value object property",
+    _validate: function() {
        must_be_expression(this, "value");
    },
 }, AST_ObjectProperty);
@@ -1040,7 +1147,6 @@ var AST_ObjectKeyVal = DEFNODE("ObjectKeyVal", "quote", {
 var AST_ObjectSetter = DEFNODE("ObjectSetter", null, {
    $documentation: "An object setter property",
    _validate: function() {
-        if (!(this.key instanceof AST_SymbolAccessor)) throw new Error("key must be AST_SymbolAccessor");
        if (!(this.value instanceof AST_Accessor)) throw new Error("value must be AST_Accessor");
    },
 }, AST_ObjectProperty);
@@ -1048,7 +1154,6 @@ var AST_ObjectSetter = DEFNODE("ObjectSetter", null, {
 var AST_ObjectGetter = DEFNODE("ObjectGetter", null, {
    $documentation: "An object getter property",
    _validate: function() {
-        if (!(this.key instanceof AST_SymbolAccessor)) throw new Error("key must be AST_SymbolAccessor");
        if (!(this.value instanceof AST_Accessor)) throw new Error("value must be AST_Accessor");
    },
 }, AST_ObjectProperty);
@@ -1065,10 +1170,6 @@ var AST_Symbol = DEFNODE("Symbol", "scope name thedef", {
    },
 });

-var AST_SymbolAccessor = DEFNODE("SymbolAccessor", null, {
-    $documentation: "The name of a property accessor (setter/getter function)"
-}, AST_Symbol);
-
 var AST_SymbolDeclaration = DEFNODE("SymbolDeclaration", "init", {
    $documentation: "A declaration symbol (symbol in var, function name or argument, symbol in catch)",
 }, AST_Symbol);
--- a/lib/compress.js
+++ b/lib/compress.js
--- a/lib/minify.js
+++ b/lib/minify.js
@@ -33,7 +33,9 @@ function read_source_map(name, toplevel) {
            return to_ascii(match[2]);
        }
    }
-    AST_Node.warn("inline source map not found: " + name);
+    AST_Node.warn("inline source map not found: {name}", {
+        name: name,
+    });
 }

 function parse_source_map(content) {
@@ -87,6 +89,7 @@ function minify(files, options) {
            toplevel: false,
            validate: false,
            warnings: false,
+            webkit: false,
            wrap: false,
        }, true);
        if (options.validate) AST_Node.enable_validation();
@@ -99,6 +102,7 @@ function minify(files, options) {
        set_shorthand("ie8", options, [ "compress", "mangle", "output" ]);
        set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
        set_shorthand("toplevel", options, [ "compress", "mangle" ]);
+        set_shorthand("webkit", options, [ "mangle", "output" ]);
        var quoted_props;
        if (options.mangle) {
            options.mangle = defaults(options.mangle, {
@@ -109,6 +113,7 @@ function minify(files, options) {
                properties: false,
                reserved: [],
                toplevel: false,
+                webkit: false,
            }, true);
            if (options.mangle.properties) {
                if (typeof options.mangle.properties != "object") {
@@ -258,6 +263,7 @@ function minify(files, options) {
    } catch (ex) {
        return { error: ex };
    } finally {
+        AST_Node.log_function();
        AST_Node.disable_validation();
    }
 }
--- a/lib/mozilla-ast.js
+++ b/lib/mozilla-ast.js
@@ -115,9 +115,6 @@
                value    : from_moz(M.value)
            };
            if (M.kind == "init") return new AST_ObjectKeyVal(args);
-            args.key = new AST_SymbolAccessor({
-                name: args.key
-            });
            args.value = new AST_Accessor(args.value);
            if (M.kind == "get") return new AST_ObjectGetter(args);
            if (M.kind == "set") return new AST_ObjectSetter(args);
@@ -385,7 +382,7 @@
    def_to_moz(AST_ObjectProperty, function To_Moz_Property(M) {
        var key = {
            type: "Literal",
-            value: M.key instanceof AST_SymbolAccessor ? M.key.name : M.key
+            value: M.key
        };
        var kind;
        if (M instanceof AST_ObjectKeyVal) {
--- a/lib/output.js
+++ b/lib/output.js
@@ -56,6 +56,7 @@ function OutputStream(options) {
        beautify         : false,
        braces           : false,
        comments         : false,
+        galio            : false,
        ie8              : false,
        indent_level     : 4,
        indent_start     : 0,
@@ -69,6 +70,7 @@ function OutputStream(options) {
        semicolons       : true,
        shebang          : true,
        source_map       : null,
+        v8               : false,
        webkit           : false,
        width            : 80,
        wrap_iife        : false,
@@ -499,11 +501,11 @@ function OutputStream(options) {
                }
            }
            if (/comment[134]/.test(c.type)) {
-                print("//" + c.value.replace(/[@#]__PURE__/g, ' ') + "\n");
+                print("//" + c.value.replace(/[@#]__PURE__/g, " ") + "\n");
                indent();
                last_nlb = true;
            } else if (c.type == "comment2") {
-                print("/*" + c.value.replace(/[@#]__PURE__/g, ' ') + "*/");
+                print("/*" + c.value.replace(/[@#]__PURE__/g, " ") + "*/");
                last_nlb = false;
            }
        });
@@ -557,10 +559,10 @@ function OutputStream(options) {
                space();
            }
            if (/comment[134]/.test(c.type)) {
-                print("//" + c.value.replace(/[@#]__PURE__/g, ' '));
+                print("//" + c.value.replace(/[@#]__PURE__/g, " "));
                need_newline_indented = true;
            } else if (c.type == "comment2") {
-                print("/*" + c.value.replace(/[@#]__PURE__/g, ' ') + "*/");
+                print("/*" + c.value.replace(/[@#]__PURE__/g, " ") + "*/");
                need_space = true;
            }
        });
@@ -610,7 +612,7 @@ function OutputStream(options) {
        },
        parent          : function(n) {
            return stack[stack.length - 2 - (n || 0)];
-        }
+        },
    };
 }

@@ -652,13 +654,7 @@ function OutputStream(options) {
    /* -----[ PARENTHESES ]----- */

    function PARENS(nodetype, func) {
-        if (Array.isArray(nodetype)) {
-            nodetype.forEach(function(nodetype) {
-                PARENS(nodetype, func);
-            });
-        } else {
-            nodetype.DEFMETHOD("needs_parens", func);
-        }
+        nodetype.DEFMETHOD("needs_parens", func);
    }

    PARENS(AST_Node, return_false);
@@ -667,11 +663,11 @@ function OutputStream(options) {
    // the first token to appear in a statement.
    PARENS(AST_Function, function(output) {
        if (!output.has_parens() && first_in_statement(output)) return true;
-        if (output.option('webkit')) {
+        if (output.option("webkit")) {
            var p = output.parent();
            if (p instanceof AST_PropAccess && p.expression === this) return true;
        }
-        if (output.option('wrap_iife')) {
+        if (output.option("wrap_iife")) {
            var p = output.parent();
            if (p instanceof AST_Call && p.expression === this) return true;
        }
@@ -679,9 +675,10 @@ function OutputStream(options) {

    // same goes for an object literal, because otherwise it would be
    // interpreted as a block of code.
-    PARENS(AST_Object, function(output) {
+    function needs_parens_obj(output) {
        return !output.has_parens() && first_in_statement(output);
-    });
+    }
+    PARENS(AST_Object, needs_parens_obj);

    PARENS(AST_Unary, function(output) {
        var p = output.parent();
@@ -699,7 +696,9 @@ function OutputStream(options) {
            // (false, true) ? (a = 10, b = 20) : (c = 30)
            // ==> 20 (side effect, set a := 10 and b := 20)
            || p instanceof AST_Conditional
+            // { [(1, 2)]: 3 }[2] ==> 3
            // { foo: (1, 2) }.foo ==> 2
+            || p instanceof AST_DestructuredKeyVal
            || p instanceof AST_ObjectProperty
            // (1, {foo:2}).foo or (1, {foo:2})["foo"] ==> 2
            || p instanceof AST_PropAccess && p.expression === this
@@ -746,7 +745,7 @@ function OutputStream(options) {
        var p = output.parent();
        if (p instanceof AST_New) return p.expression === this;
        // https://bugs.webkit.org/show_bug.cgi?id=123506
-        if (output.option('webkit')) {
+        if (output.option("webkit")) {
            var g = output.parent(1);
            return this.expression instanceof AST_Function
                && p instanceof AST_PropAccess
@@ -769,24 +768,36 @@ function OutputStream(options) {
        var p = output.parent();
        if (p instanceof AST_PropAccess && p.expression === this) {
            var value = this.value;
-            // https://github.com/mishoo/UglifyJS/issues/115
-            // https://github.com/mishoo/UglifyJS/pull/1009
-            return value < 0 || /^0/.test(make_num(value));
+                // https://github.com/mishoo/UglifyJS/issues/115
+            return value < 0
+                // https://github.com/mishoo/UglifyJS/pull/1009
+                || output.option("galio") && /^0/.test(make_num(value));
        }
    });

-    PARENS([ AST_Assign, AST_Conditional ], function(output) {
+    function needs_parens_assign_cond(self, output) {
        var p = output.parent();
        // 1 + (a = 2) + 3 → 6, side effect setting a = 2
        if (p instanceof AST_Binary) return !(p instanceof AST_Assign);
        // (a = func)() —or— new (a = Object)()
-        if (p instanceof AST_Call) return p.expression === this;
+        if (p instanceof AST_Call) return p.expression === self;
        // (a = foo) ? bar : baz
-        if (p instanceof AST_Conditional) return p.condition === this;
+        if (p instanceof AST_Conditional) return p.condition === self;
        // (a = foo)["prop"] —or— (a = foo).prop
-        if (p instanceof AST_PropAccess) return p.expression === this;
+        if (p instanceof AST_PropAccess) return p.expression === self;
        // !(a = false) → true
        if (p instanceof AST_Unary) return true;
+    }
+    PARENS(AST_Assign, function(output) {
+        if (needs_parens_assign_cond(this, output)) return true;
+        //  v8 parser bug   =>     workaround
+        // f([1], [a] = []) => f([1], ([a] = []))
+        if (output.option("v8")) return this.left instanceof AST_Destructured;
+        // ({ p: a } = o);
+        if (this.left instanceof AST_DestructuredObject) return needs_parens_obj(output);
+    });
+    PARENS(AST_Conditional, function(output) {
+        return needs_parens_assign_cond(this, output);
    });

    /* -----[ PRINTERS ]----- */
@@ -1273,6 +1284,38 @@ function OutputStream(options) {
            output.space();
        } : noop);
    });
+    DEFPRINT(AST_DestructuredArray, function(output) {
+        var a = this.elements, len = a.length;
+        output.with_square(len > 0 ? function() {
+            output.space();
+            a.forEach(function(exp, i) {
+                if (i) output.comma();
+                exp.print(output);
+                // If the final element is a hole, we need to make sure it
+                // doesn't look like a trailing comma, by inserting an actual
+                // trailing comma.
+                if (i === len - 1 && exp instanceof AST_Hole)
+                  output.comma();
+            });
+            output.space();
+        } : noop);
+    });
+    DEFPRINT(AST_DestructuredKeyVal, print_key_value);
+    DEFPRINT(AST_DestructuredObject, function(output) {
+        var props = this.properties;
+        if (props.length > 0) output.with_block(function() {
+            props.forEach(function(prop, i) {
+                if (i) {
+                    output.print(",");
+                    output.newline();
+                }
+                output.indent();
+                prop.print(output);
+            });
+            output.newline();
+        });
+        else print_braced_empty(this, output);
+    });
    DEFPRINT(AST_Object, function(output) {
        var props = this.properties;
        if (props.length > 0) output.with_block(function() {
@@ -1289,34 +1332,43 @@ function OutputStream(options) {
        else print_braced_empty(this, output);
    });

-    function print_property_name(key, quote, output) {
-        if (output.option("quote_keys")) {
+    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);
        } else if ("" + +key == key && key >= 0) {
            output.print(make_num(key));
-        } else if (RESERVED_WORDS[key] ? !output.option("ie8") : is_identifier_string(key)) {
-            if (quote && output.option("keep_quoted_props")) {
-                output.print_string(key, quote);
-            } else {
-                output.print_name(key);
-            }
        } else {
-            output.print_string(key, quote);
+            var quote = self.start && self.start.quote;
+            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);
+                }
+            } else {
+                output.print_string(key, quote);
+            }
        }
    }

-    DEFPRINT(AST_ObjectKeyVal, function(output) {
+    function print_key_value(output) {
        var self = this;
-        print_property_name(self.key, self.quote, output);
+        print_property_key(self, output);
        output.colon();
        self.value.print(output);
-    });
+    }
+    DEFPRINT(AST_ObjectKeyVal, print_key_value);
    function print_accessor(type) {
        return function(output) {
            var self = this;
            output.print(type);
            output.space();
-            print_property_name(self.key.name, self.quote, output);
+            print_property_key(self, output);
            self.value._codegen(output, true);
        };
    }
@@ -1474,6 +1526,7 @@ function OutputStream(options) {
        AST_Constant,
        AST_Debugger,
        AST_Definitions,
+        AST_Destructured,
        AST_Finally,
        AST_Jump,
        AST_Lambda,
@@ -1488,14 +1541,7 @@ function OutputStream(options) {
        output.add_mapping(this.start);
    });

-    DEFMAP([
-        AST_ObjectGetter,
-        AST_ObjectSetter,
-     ], function(output) {
-        output.add_mapping(this.start, this.key.name);
-    });
-
-    DEFMAP([ AST_ObjectProperty ], function(output) {
-        output.add_mapping(this.start, this.key);
+    DEFMAP([ AST_DestructuredKeyVal, AST_ObjectProperty ], function(output) {
+        if (typeof this.key == "string") output.add_mapping(this.start, this.key);
    });
 })();
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -753,7 +753,7 @@ function parse($TEXT, options) {
        }
    }

-    var statement = embed_tokens(function(strict_defun) {
+    var statement = embed_tokens(function() {
        handle_regexp();
        switch (S.token.type) {
          case "string":
@@ -844,9 +844,6 @@ function parse($TEXT, options) {
                return for_();

              case "function":
-                if (!strict_defun && S.input.has_directive("use strict")) {
-                    croak("In strict mode code, functions can only be declared at top level or immediately within another function.");
-                }
                next();
                return function_(AST_Defun);

@@ -976,14 +973,16 @@ function parse($TEXT, options) {
        if (!is("punc", ";")) {
            init = is("keyword", "const")
                ? (next(), const_(true))
+                : is("keyword", "let")
+                ? (next(), let_(true))
                : is("keyword", "var")
                ? (next(), var_(true))
                : expression(true, true);
            if (is("operator", "in")) {
-                if (init instanceof AST_Var) {
+                if (init instanceof AST_Definitions) {
                    if (init.definitions.length > 1)
                        croak("Only one variable declaration allowed in for..in loop", init.start.line, init.start.col, init.start.pos);
-                } else if (!is_assignable(init)) {
+                } else if (!(is_assignable(init) || (init = to_destructured(init)) instanceof AST_Destructured)) {
                    croak("Invalid left-hand side in for..in loop", init.start.line, init.start.col, init.start.pos);
                }
                next();
@@ -1028,7 +1027,7 @@ function parse($TEXT, options) {
        var argnames = [];
        for (var first = true; !is("punc", ")");) {
            if (first) first = false; else expect(",");
-            argnames.push(as_symbol(AST_SymbolFunarg));
+            argnames.push(maybe_destructured(AST_SymbolFunarg));
        }
        next();
        var loop = S.in_loop;
@@ -1038,7 +1037,7 @@ function parse($TEXT, options) {
        S.input.push_directives_stack();
        S.in_loop = 0;
        S.labels = [];
-        var body = block_(true);
+        var body = block_();
        if (S.input.has_directive("use strict")) {
            if (name) strict_verify_symbol(name);
            argnames.forEach(strict_verify_symbol);
@@ -1067,12 +1066,12 @@ function parse($TEXT, options) {
        });
    }

-    function block_(strict_defun) {
+    function block_() {
        expect("{");
        var a = [];
        while (!is("punc", "}")) {
            if (is("eof")) expect_token("punc", "}");
-            a.push(statement(strict_defun));
+            a.push(statement());
        }
        next();
        return a;
@@ -1149,16 +1148,16 @@ function parse($TEXT, options) {
        });
    }

-    function vardefs(type, no_in, must_init) {
+    function vardefs(type, no_in) {
        var a = [];
        for (;;) {
            var start = S.token;
-            var name = as_symbol(type);
+            var name = maybe_destructured(type);
            var value = null;
            if (is("operator", "=")) {
                next();
                value = expression(false, no_in);
-            } else if (must_init) {
+            } else if (!no_in && (type === AST_SymbolConst || name instanceof AST_Destructured)) {
                croak("Missing initializer in declaration");
            }
            a.push(new AST_VarDef({
@@ -1177,7 +1176,7 @@ function parse($TEXT, options) {
    var const_ = function(no_in) {
        return new AST_Const({
            start       : prev(),
-            definitions : vardefs(AST_SymbolConst, no_in, true),
+            definitions : vardefs(AST_SymbolConst, no_in),
            end         : prev()
        });
    };
@@ -1222,7 +1221,7 @@ function parse($TEXT, options) {
        var tok = S.token, ret;
        switch (tok.type) {
          case "name":
-            ret = _make_symbol(AST_SymbolRef);
+            ret = _make_symbol(AST_SymbolRef, tok);
            break;
          case "num":
            ret = new AST_Number({ start: tok, end: tok, value: tok.value });
@@ -1309,7 +1308,8 @@ function parse($TEXT, options) {
        unexpected();
    };

-    function expr_list(closing, allow_trailing_comma, allow_empty) {
+    function expr_list(closing, allow_trailing_comma, allow_empty, parser) {
+        if (!parser) parser = expression;
        var first = true, a = [];
        while (!is("punc", closing)) {
            if (first) first = false; else expect(",");
@@ -1317,7 +1317,7 @@ function parse($TEXT, options) {
            if (is("punc", ",") && allow_empty) {
                a.push(new AST_Hole({ start: S.token, end: S.token }));
            } else {
-                a.push(expression(false));
+                a.push(parser());
            }
        }
        next();
@@ -1340,51 +1340,62 @@ function parse($TEXT, options) {
        var first = true, a = [];
        while (!is("punc", "}")) {
            if (first) first = false; else expect(",");
-            if (!options.strict && is("punc", "}"))
-                // allow trailing comma
-                break;
+            // allow trailing comma
+            if (!options.strict && is("punc", "}")) break;
            var start = S.token;
-            var type = start.type;
-            var name = as_property_name();
-            if (type == "name" && !is("punc", ":")) {
-                var key = new AST_SymbolAccessor({
-                    start: S.token,
-                    name: "" + as_property_name(),
-                    end: prev()
-                });
-                if (name == "get") {
-                    a.push(new AST_ObjectGetter({
-                        start : start,
-                        key   : key,
-                        value : create_accessor(),
-                        end   : prev()
-                    }));
-                    continue;
-                }
-                if (name == "set") {
-                    a.push(new AST_ObjectSetter({
-                        start : start,
-                        key   : key,
-                        value : create_accessor(),
-                        end   : prev()
-                    }));
-                    continue;
-                }
+            var key = as_property_key();
+            if (is("punc", "(")) {
+                var func_start = S.token;
+                var func = function_(AST_Function);
+                func.start = func_start;
+                func.end = prev();
+                a.push(new AST_ObjectKeyVal({
+                    start: start,
+                    key: key,
+                    value: func,
+                    end: prev(),
+                }));
+                continue;
+            }
+            if (!is("punc", ":") && start.type == "name") switch (key) {
+              case "get":
+                a.push(new AST_ObjectGetter({
+                    start: start,
+                    key: as_property_key(),
+                    value: create_accessor(),
+                    end: prev(),
+                }));
+                continue;
+              case "set":
+                a.push(new AST_ObjectSetter({
+                    start: start,
+                    key: as_property_key(),
+                    value: create_accessor(),
+                    end: prev(),
+                }));
+                continue;
+              default:
+                a.push(new AST_ObjectKeyVal({
+                    start: start,
+                    key: key,
+                    value: _make_symbol(AST_SymbolRef, start),
+                    end: prev(),
+                }));
+                continue;
            }
            expect(":");
            a.push(new AST_ObjectKeyVal({
-                start : start,
-                quote : start.quote,
-                key   : "" + name,
-                value : expression(false),
-                end   : prev()
+                start: start,
+                key: key,
+                value: expression(false),
+                end: prev(),
            }));
        }
        next();
        return new AST_Object({ properties: a });
    });

-    function as_property_name() {
+    function as_property_key() {
        var tmp = S.token;
        switch (tmp.type) {
          case "operator":
@@ -1395,7 +1406,13 @@ function parse($TEXT, options) {
          case "keyword":
          case "atom":
            next();
-            return tmp.value;
+            return "" + tmp.value;
+          case "punc":
+            if (tmp.value != "[") unexpected();
+            next();
+            var key = expression(false);
+            expect("]");
+            return key;
          default:
            unexpected();
        }
@@ -1408,12 +1425,12 @@ function parse($TEXT, options) {
        return name;
    }

-    function _make_symbol(type) {
-        var name = S.token.value;
-        return new (name == "this" ? AST_This : type)({
-            name  : String(name),
-            start : S.token,
-            end   : S.token
+    function _make_symbol(type, token) {
+        var name = token.value;
+        return new (name === "this" ? AST_This : type)({
+            name: "" + name,
+            start: token,
+            end: token,
        });
    }

@@ -1427,7 +1444,7 @@ function parse($TEXT, options) {
            if (!noerror) croak("Name expected");
            return null;
        }
-        var sym = _make_symbol(type);
+        var sym = _make_symbol(type, S.token);
        if (S.input.has_directive("use strict") && sym instanceof AST_SymbolDeclaration) {
            strict_verify_symbol(sym);
        }
@@ -1435,6 +1452,54 @@ function parse($TEXT, options) {
        return sym;
    }

+    function maybe_destructured(type) {
+        var start = S.token;
+        if (is("punc", "[")) {
+            next();
+            return new AST_DestructuredArray({
+                start: start,
+                elements: expr_list("]", !options.strict, true, function() {
+                    return maybe_destructured(type);
+                }),
+                end: prev(),
+            });
+        }
+        if (is("punc", "{")) {
+            next();
+            var first = true, a = [];
+            while (!is("punc", "}")) {
+                if (first) first = false; else expect(",");
+                // allow trailing comma
+                if (!options.strict && is("punc", "}")) break;
+                var key_start = S.token;
+                var key = as_property_key();
+                if (!is("punc", ":") && key_start.type == "name") {
+                    a.push(new AST_DestructuredKeyVal({
+                        start: key_start,
+                        key: key,
+                        value: _make_symbol(type, key_start),
+                        end: prev(),
+                    }));
+                    continue;
+                }
+                expect(":");
+                a.push(new AST_DestructuredKeyVal({
+                    start: key_start,
+                    key: key,
+                    value: maybe_destructured(type),
+                    end: prev(),
+                }));
+            }
+            next();
+            return new AST_DestructuredObject({
+                start: start,
+                properties: a,
+                end: prev(),
+            });
+        }
+        return as_symbol(type);
+    }
+
    function mark_pure(call) {
        var start = call.start;
        var comments = start.comments_before;
@@ -1564,11 +1629,43 @@ function parse($TEXT, options) {
        return expr instanceof AST_PropAccess || expr instanceof AST_SymbolRef;
    }

+    function to_destructured(node) {
+        if (node instanceof AST_Array) {
+            var elements = node.elements.map(to_destructured);
+            return all(elements, function(node) {
+                return node instanceof AST_Destructured || node instanceof AST_Hole || is_assignable(node);
+            }) ? new AST_DestructuredArray({
+                start: node.start,
+                elements: elements,
+                end: node.end,
+            }) : node;
+        }
+        if (!(node instanceof AST_Object)) return node;
+        var props = [];
+        for (var i = 0; i < node.properties.length; i++) {
+            var prop = node.properties[i];
+            if (!(prop instanceof AST_ObjectKeyVal)) return node;
+            var value = to_destructured(prop.value);
+            if (!(value instanceof AST_Destructured || is_assignable(value))) return node;
+            props.push(new AST_DestructuredKeyVal({
+                start: prop.start,
+                key: prop.key,
+                value: value,
+                end: prop.end,
+            }));
+        }
+        return new AST_DestructuredObject({
+            start: node.start,
+            properties: props,
+            end: node.end,
+        });
+    }
+
    var maybe_assign = function(no_in) {
        var start = S.token;
        var left = maybe_conditional(no_in), val = S.token.value;
        if (is("operator") && ASSIGNMENT[val]) {
-            if (is_assignable(left)) {
+            if (is_assignable(left) || val == "=" && (left = to_destructured(left)) instanceof AST_Destructured) {
                next();
                return new AST_Assign({
                    start    : start,
@@ -1616,7 +1713,7 @@ function parse($TEXT, options) {
        var body = [];
        S.input.push_directives_stack();
        while (!is("eof"))
-            body.push(statement(true));
+            body.push(statement());
        S.input.pop_directives_stack();
        var end = prev();
        var toplevel = options.toplevel;
--- a/lib/propmangle.js
+++ b/lib/propmangle.js
@@ -81,8 +81,8 @@ var builtins = function() {

 function reserve_quoted_keys(ast, reserved) {
    ast.walk(new TreeWalker(function(node) {
-        if (node instanceof AST_ObjectKeyVal) {
-            if (node.quote) add(node.key);
+        if (node instanceof AST_ObjectProperty) {
+            if (node.start && node.start.quote) add(node.key);
        } else if (node instanceof AST_Sub) {
            addStrings(node.property, add);
        }
@@ -165,11 +165,8 @@ function mangle_properties(ast, options) {
            }
        } else if (node instanceof AST_Dot) {
            add(node.property);
-        } else if (node instanceof AST_ObjectKeyVal) {
-            add(node.key);
        } else if (node instanceof AST_ObjectProperty) {
-            // setter or getter, since KeyVal is handled above
-            add(node.key.name);
+            if (typeof node.key == "string") add(node.key);
        } else if (node instanceof AST_Sub) {
            addStrings(node.property, add);
        }
@@ -198,11 +195,8 @@ function mangle_properties(ast, options) {
            }
        } else if (node instanceof AST_Dot) {
            node.property = mangle(node.property);
-        } else if (node instanceof AST_ObjectKeyVal) {
-            node.key = mangle(node.key);
        } else if (node instanceof AST_ObjectProperty) {
-            // setter or getter
-            node.key.name = mangle(node.key.name);
+            if (typeof node.key == "string") node.key = mangle(node.key);
        } else if (node instanceof AST_Sub) {
            if (!options.keep_quoted) mangleStrings(node.property);
        }
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -72,7 +72,7 @@ SymbolDef.prototype = {
            if (def) {
                this.mangled_name = def.mangled_name || def.name;
            } else {
-                this.mangled_name = next_mangled_name(this.scope, options, this);
+                this.mangled_name = next_mangled_name(this, options);
            }
            if (this.global && cache) {
                cache.set(this.name, this.mangled_name);
@@ -204,7 +204,17 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {

    // pass 2: find back references and eval
    self.globals = new Dictionary();
+    var in_arg = [];
    var tw = new TreeWalker(function(node) {
+        if (node instanceof AST_Lambda) {
+            in_arg.push(node);
+            node.argnames.forEach(function(argname) {
+                argname.walk(tw);
+            });
+            in_arg.pop();
+            walk_body(node, tw);
+            return true;
+        }
        if (node instanceof AST_LoopControl) {
            if (node.label) node.label.thedef.references.push(node);
            return true;
@@ -212,10 +222,24 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
        if (node instanceof AST_SymbolRef) {
            var name = node.name;
            var sym = node.scope.find_variable(name);
+            for (var i = in_arg.length; i > 0 && sym;) {
+                i = in_arg.lastIndexOf(sym.scope, i - 1);
+                if (i < 0) break;
+                var decl = sym.orig[0];
+                if (decl instanceof AST_SymbolFunarg || decl instanceof AST_SymbolLambda) {
+                    node.in_arg = true;
+                    break;
+                }
+                sym = sym.scope.parent_scope.find_variable(name);
+            }
            if (!sym) {
                sym = self.def_global(node);
            } else if (name == "arguments" && sym.scope instanceof AST_Lambda) {
-                sym.scope.uses_arguments = true;
+                if (!(tw.parent() instanceof AST_PropAccess)) {
+                    sym.scope.uses_arguments = "d";
+                } else if (!sym.scope.uses_arguments) {
+                    sym.scope.uses_arguments = true;
+                }
            }
            if (name == "eval") {
                var parent = tw.parent();
@@ -408,7 +432,8 @@ function names_in_use(scope, options) {
    return names;
 }

-function next_mangled_name(scope, options, def) {
+function next_mangled_name(def, options) {
+    var scope = def.scope;
    var in_use = names_in_use(scope, options);
    var holes = scope.cname_holes;
    var names = Object.create(null);
@@ -461,6 +486,7 @@ function _default_mangler_options(options) {
        keep_fnames : false,
        reserved    : [],
        toplevel    : false,
+        webkit      : false,
    });
    if (!Array.isArray(options.reserved)) options.reserved = [];
    // Never mangle arguments
@@ -495,9 +521,24 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
            return true;
        }
        if (node instanceof AST_BlockScope) {
-            var to_mangle = [];
+            if (options.webkit && node instanceof AST_IterationStatement && node.init instanceof AST_Let) {
+                node.init.definitions.forEach(function(defn) {
+                    defn.name.match_symbol(function(sym) {
+                        if (!(sym instanceof AST_SymbolLet)) return;
+                        var def = sym.definition();
+                        var scope = sym.scope.parent_scope;
+                        var redef = scope.def_variable(sym);
+                        sym.thedef = def;
+                        scope.to_mangle.push(redef);
+                        def.redefined = function() {
+                            return redef;
+                        };
+                    });
+                }, true);
+            }
+            node.to_mangle = [];
            node.variables.each(function(def) {
-                if (!defer_redef(def)) to_mangle.push(def);
+                if (!defer_redef(def)) node.to_mangle.push(def);
            });
            descend();
            if (options.cache && node instanceof AST_Toplevel) {
@@ -508,7 +549,7 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
                sym.scope = node;
                sym.reference(options);
            }
-            to_mangle.forEach(mangle);
+            node.to_mangle.forEach(mangle);
            return true;
        }
        if (node instanceof AST_Label) {
@@ -528,13 +569,19 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
        def.mangle(options);
    }

-    function defer_redef(def, node) {
+    function defer_redef(def) {
+        var sym = def.orig[0];
        var redef = def.redefined();
-        if (!redef) return false;
+        if (!redef) {
+            if (!(sym instanceof AST_SymbolConst)) return false;
+            var scope = def.scope.resolve();
+            if (def.scope === scope) return false;
+            redef = scope.def_variable(sym);
+            scope.to_mangle.push(redef);
+        }
        redefined.push(def);
        def.references.forEach(reference);
-        var node = def.orig[0];
-        if (node instanceof AST_SymbolCatch || node instanceof AST_SymbolConst) reference(node);
+        if (sym instanceof AST_SymbolCatch || sym instanceof AST_SymbolConst) reference(sym);
        return true;

        function reference(sym) {
--- a/lib/transform.js
+++ b/lib/transform.js
@@ -160,10 +160,21 @@ TreeTransformer.prototype = new TreeWalker;
    DEF(AST_Array, function(self, tw) {
        self.elements = do_list(self.elements, tw);
    });
+    DEF(AST_DestructuredArray, function(self, tw) {
+        self.elements = do_list(self.elements, tw);
+    });
+    DEF(AST_DestructuredKeyVal, function(self, tw) {
+        if (self.key instanceof AST_Node) self.key = self.key.transform(tw);
+        self.value = self.value.transform(tw);
+    });
+    DEF(AST_DestructuredObject, function(self, tw) {
+        self.properties = do_list(self.properties, tw);
+    });
    DEF(AST_Object, function(self, tw) {
        self.properties = do_list(self.properties, tw);
    });
    DEF(AST_ObjectProperty, function(self, tw) {
+        if (self.key instanceof AST_Node) self.key = self.key.transform(tw);
        self.value = self.value.transform(tw);
    });
 })(function(node, descend) {
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -143,8 +143,9 @@ function push_uniq(array, el) {
 }

 function string_template(text, props) {
-    return text.replace(/\{(.+?)\}/g, function(str, p) {
-        return props && props[p];
+    return text.replace(/\{([^}]+)\}/g, function(str, p) {
+        var value = props[p];
+        return value instanceof AST_Node ? value.print_to_string() : value;
    });
 }

--- a/package.json
+++ b/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": "3.11.4",
+  "version": "3.12.0",
  "engines": {
    "node": ">=0.8.0"
  },
--- a/test/compress.js
+++ b/test/compress.js
@@ -63,7 +63,6 @@ function make_code(ast, options) {

 function parse_test(file) {
    var script = fs.readFileSync(file, "utf8");
-    // TODO try/catch can be removed after fixing https://github.com/mishoo/UglifyJS/issues/348
    try {
        var ast = U.parse(script, {
            filename: file
@@ -315,6 +314,7 @@ function test_case(test) {
        if (test.mangle.properties) U.mangle_properties(output, test.mangle.properties);
    }
    var output_code = make_code(output, output_options);
+    U.AST_Node.log_function();
    if (expect != output_code) {
        log([
            "!!! failed",
@@ -386,7 +386,7 @@ function test_case(test) {
            mangle: test.mangle
        });
        var actual = stdout[toplevel ? 1 : 0];
-        if (test.expect_stdout === true) {
+        if (test.expect_stdout === true || test.expect_stdout instanceof Error && test.expect_stdout.name === actual.name) {
            test.expect_stdout = actual;
        }
        if (!sandbox.same_stdout(test.expect_stdout, actual)) {
--- a/test/compress/arguments.js
+++ b/test/compress/arguments.js
@@ -807,3 +807,47 @@ issue_4200: {
    }
    expect_stdout: "undefined"
 }
+
+issue_4291_1: {
+    options = {
+        arguments: true,
+        keep_fargs: "strict",
+    }
+    input: {
+        console.log(function() {
+            arguments[0] = "PASS";
+            return arguments;
+        }()[0]);
+    }
+    expect: {
+        console.log(function() {
+            arguments[0] = "PASS";
+            return arguments;
+        }()[0]);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4291_2: {
+    options = {
+        arguments: true,
+        keep_fargs: "strict",
+    }
+    input: {
+        var a = function() {
+            if (arguments[0])
+                arguments[1] = "PASS";
+            return arguments;
+        }(42);
+        console.log(a[1], a[0], a.length);
+    }
+    expect: {
+        var a = function(argument_0) {
+            if (argument_0)
+                arguments[1] = "PASS";
+            return arguments;
+        }(42);
+        console.log(a[1], a[0], a.length);
+    }
+    expect_stdout: "PASS 42 1"
+}
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -8577,3 +8577,28 @@ issue_4242: {
    }
    expect_stdout: "undefined"
 }
+
+issue_4248: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = 0;
+        try {
+            a = 1;
+            b[1];
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect: {
+        var a = 0;
+        try {
+            a = 1;
+            b[1];
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect_stdout: "1"
+}
--- a/test/compress/conditionals.js
+++ b/test/compress/conditionals.js
@@ -83,13 +83,11 @@ ifs_3_should_warn: {
        "WARN: Condition left of && always false [test/compress/conditionals.js:3,12]",
        "WARN: Condition always false [test/compress/conditionals.js:3,12]",
        "WARN: Dropping unreachable code [test/compress/conditionals.js:3,34]",
-        "WARN: Declarations in unreachable code! [test/compress/conditionals.js:4,12]",
        "WARN: + in boolean context always true [test/compress/conditionals.js:10,19]",
        "WARN: Boolean || always true [test/compress/conditionals.js:10,12]",
        "WARN: Condition left of || always true [test/compress/conditionals.js:10,12]",
        "WARN: Condition always true [test/compress/conditionals.js:10,12]",
        "WARN: Dropping unreachable code [test/compress/conditionals.js:12,15]",
-        "WARN: Declarations in unreachable code! [test/compress/conditionals.js:13,12]",
        "WARN: Dropping side-effect-free statement [test/compress/conditionals.js:3,12]",
        "WARN: Dropping side-effect-free statement [test/compress/conditionals.js:10,12]",
    ]
--- a/test/compress/const.js
+++ b/test/compress/const.js
@@ -1,3 +1,45 @@
+mangle_block: {
+    mangle = {
+        toplevel: false,
+    }
+    input: {
+        var o = "PASS";
+        {
+            const a = "FAIL";
+        }
+        console.log(o);
+    }
+    expect: {
+        var o = "PASS";
+        {
+            const a = "FAIL";
+        }
+        console.log(o);
+    }
+    expect_stdout: "PASS"
+}
+
+mangle_block_toplevel: {
+    mangle = {
+        toplevel: true,
+    }
+    input: {
+        var o = "PASS";
+        {
+            const a = "FAIL";
+        }
+        console.log(o);
+    }
+    expect: {
+        var o = "PASS";
+        {
+            const c = "FAIL";
+        }
+        console.log(o);
+    }
+    expect_stdout: "PASS"
+}
+
 mangle_catch_1: {
    mangle = {}
    input: {
@@ -11,8 +53,8 @@ mangle_catch_1: {
    expect: {
        try {
            throw "eeeee";
-        } catch (e) {
-            const o = typeof d;
+        } catch (o) {
+            const e = typeof d;
        }
        console.log(typeof a, typeof b);
    }
@@ -57,6 +99,23 @@ retain_block: {
    expect_stdout: true
 }

+retain_catch: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        try {} catch (a) {
+            const a = "aa";
+        }
+    }
+    expect: {
+        try {} catch (a) {
+            const a = "aa";
+        }
+    }
+    expect_stdout: true
+}
+
 if_dead_branch: {
    options = {
        conditionals: true,
@@ -1084,3 +1143,207 @@ issue_4231: {
    }
    expect_stdout: "function"
 }
+
+issue_4245: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        const a = f();
+        function f() {
+            typeof a;
+        }
+    }
+    expect: {
+        const a = f();
+        function f() {
+            a,
+            1;
+        }
+    }
+    expect_stdout: true
+}
+
+issue_4248: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            (function() {
+                a = "PASS";
+                b[a];
+                const b = 0;
+            })();
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect: {
+        var a = "FAIL";
+        try {
+            (function() {
+                a = "PASS";
+                b[a];
+                const b = 0;
+            })();
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4261: {
+    options = {
+        inline: true,
+        reduce_funcs: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        {
+            const a = 42;
+            (function() {
+                function f() {
+                    console.log(a);
+                }
+                function g() {
+                    while (f());
+                }
+                (function() {
+                    while (g());
+                })();
+            })();
+        }
+    }
+    expect: {
+        {
+            const a = 42;
+            (function() {
+                function g() {
+                    while (void console.log(a));
+                }
+                (function() {
+                    while (g());
+                })();
+            })();
+        }
+    }
+    expect_stdout: "42"
+}
+
+issue_4274_1: {
+    options = {
+        loops: true,
+    }
+    input: {
+        for (;;) {
+            if (console.log("PASS")) {
+                const a = 0;
+            } else {
+                break;
+                var a;
+            }
+        }
+    }
+    expect: {
+        for (; console.log("PASS");) {
+            {
+                const a = 0;
+            }
+            var a;
+        }
+    }
+    expect_stdout: true
+}
+
+issue_4274_2: {
+    options = {
+        loops: true,
+    }
+    input: {
+        for (;;) {
+            if (!console.log("PASS")) {
+                break;
+                var a;
+            } else {
+                const a = 0;
+            }
+        }
+    }
+    expect: {
+        for (; console.log("PASS");) {
+            {
+                const a = 0;
+            }
+            var a;
+        }
+    }
+    expect_stdout: true
+}
+
+issue_4290_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        const a = 0;
+        var a;
+    }
+    expect: {
+        const a = 0;
+        var a;
+    }
+    expect_stdout: true
+}
+
+issue_4305_1: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            const arguments = function() {
+                while (console.log("PASS"));
+            };
+            arguments();
+        })();
+    }
+    expect: {
+        (function() {
+            const arguments = function() {
+                while (console.log("PASS"));
+            };
+            arguments();
+        })();
+    }
+    expect_stdout: true
+}
+
+issue_4305_2: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            const a = function() {
+                while (console.log("aaaaa"));
+            };
+            a();
+        })();
+    }
+    expect: {
+        (function(a) {
+            const a = function() {
+                while (console.log("aaaaa"));
+            };
+            a();
+        })();
+    }
+    expect_stdout: true
+}
--- a/test/compress/dead-code.js
+++ b/test/compress/dead-code.js
@@ -61,8 +61,6 @@ dead_code_2_should_warn: {
    expect_stdout: true
    expect_warnings: [
        "WARN: Dropping unreachable code [test/compress/dead-code.js:8,12]",
-        "WARN: Declarations in unreachable code! [test/compress/dead-code.js:10,16]",
-        "WARN: Dropping unreachable code [test/compress/dead-code.js:10,16]",
    ]
    node_version: "<=4"
 }
@@ -103,11 +101,9 @@ dead_code_constant_boolean_should_warn_more: {
        "WARN: + in boolean context always true [test/compress/dead-code.js:1,33]",
        "WARN: Boolean || always true [test/compress/dead-code.js:1,16]",
        "WARN: Dropping unreachable code [test/compress/dead-code.js:1,45]",
-        "WARN: Declarations in unreachable code! [test/compress/dead-code.js:3,12]",
        "WARN: Boolean expression always true [test/compress/dead-code.js:6,47]",
        "WARN: Boolean && always false [test/compress/dead-code.js:6,28]",
        "WARN: Dropping unreachable code [test/compress/dead-code.js:6,63]",
-        "WARN: Declarations in unreachable code! [test/compress/dead-code.js:9,12]",
        "WARN: Dropping side-effect-free statement [test/compress/dead-code.js:1,15]",
        "WARN: Dropping side-effect-free statement [test/compress/dead-code.js:6,28]",
    ]
--- a/test/compress/destructured.js
+++ b/test/compress/destructured.js
--- a/test/compress/evaluate.js
+++ b/test/compress/evaluate.js
@@ -3047,3 +3047,30 @@ issue_4214: {
    }
    expect_stdout: "NaN"
 }
+
+issue_4271: {
+    options = {
+        evaluate: true,
+        unsafe: true,
+    }
+    input: {
+        ({
+            p: null,
+            q: (console.log("foo"), 42),
+            p: function() {}
+        })[console.log("bar"), "p"] && console.log("PASS");
+    }
+    expect: {
+        ({
+            p: null,
+            q: (console.log("foo"), 42),
+            p: function() {}
+        })[console.log("bar"), "p"],
+        console.log("PASS");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "PASS",
+    ]
+}
--- a/test/compress/functions.js
+++ b/test/compress/functions.js
@@ -521,7 +521,7 @@ issue_2531_2: {
    options = {
        evaluate: true,
        inline: true,
-        passes: 3,
+        passes: 2,
        reduce_funcs: true,
        reduce_vars: true,
        side_effects: true,
@@ -556,9 +556,10 @@ issue_2531_3: {
    options = {
        evaluate: true,
        inline: true,
-        passes: 3,
+        passes: 2,
        reduce_funcs: true,
        reduce_vars: true,
+        sequences: true,
        side_effects: true,
        toplevel: true,
        unused: true,
@@ -2081,7 +2082,7 @@ issue_3016_1: {
        var b = 1;
        do {
            3[b];
-        } while(0);
+        } while (0);
        console.log(b);
    }
    expect_stdout: "1"
@@ -2112,7 +2113,7 @@ issue_3016_2: {
        do {
            a = 3,
            a[b];
-        } while(0);
+        } while (0);
        var a;
        console.log(b);
    }
@@ -2145,7 +2146,7 @@ issue_3016_2_ie8: {
        do {
            a = 3,
            a[b];
-        } while(0);
+        } while (0);
        var a;
        console.log(b);
    }
@@ -2175,7 +2176,7 @@ issue_3016_3: {
        var b = 1;
        do {
            console.log((a = void 0, a ? "FAIL" : a = "PASS"));
-        } while(b--);
+        } while (b--);
        var a;
    }
    expect_stdout: [
@@ -2208,7 +2209,7 @@ issue_3016_3_ie8: {
        var b = 1;
        do {
            console.log((a = void 0, a ? "FAIL" : a = "PASS"));
-        } while(b--);
+        } while (b--);
        var a;
    }
    expect_stdout: [
@@ -5115,3 +5116,102 @@ issue_4233: {
    }
    expect_stdout: "number"
 }
+
+issue_4259: {
+    options = {
+        collapse_vars: true,
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function b() {
+            var c = b;
+            for (b in c);
+        };
+        a();
+        console.log(typeof a);
+    }
+    expect: {
+        function a() {
+            for (a in a);
+        }
+        a();
+        console.log(typeof a);
+    }
+    expect_stdout: "function"
+}
+
+issue_4261: {
+    options = {
+        inline: true,
+        reduce_funcs: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        try {
+            throw 42;
+        } catch (e) {
+            (function() {
+                function f() {
+                    e.p;
+                }
+                function g() {
+                    while (f());
+                }
+                (function() {
+                    while (console.log(g()));
+                })();
+            })();
+        }
+    }
+    expect: {
+        try {
+            throw 42;
+        } catch (e) {
+            (function() {
+                function g() {
+                    while (void e.p);
+                }
+                (function() {
+                    while (console.log(g()));
+                })();
+            })();
+        }
+    }
+    expect_stdout: true
+}
+
+issue_4265: {
+    options = {
+        conditionals: true,
+        dead_code: true,
+        inline: true,
+        sequences: true,
+    }
+    input: {
+        function f() {
+            console;
+            if ([ function() {
+                return this + console.log(a);
+                a;
+                var a;
+            }() ]);
+            return 0;
+        }
+        f();
+    }
+    expect: {
+        function f() {
+            return console, function() {
+                return console.log(a);
+                var a;
+            }(), 0;
+        }
+        f();
+    }
+    expect_stdout: "undefined"
+}
--- a/test/compress/hoist_props.js
+++ b/test/compress/hoist_props.js
@@ -297,6 +297,33 @@ name_collision_3: {
    expect_stdout: "true 4 6"
 }

+name_collision_4: {
+    options = {
+        hoist_props: true,
+        reduce_vars: true,
+    }
+    input: {
+        console.log(function() {
+            var o = {
+                p: 0,
+                q: "PASS",
+            };
+            return function(o_p) {
+                if (!o.p) return o_p;
+            }(o.q);
+        }());
+    }
+    expect: {
+        console.log(function() {
+            var o_p$0 = 0, o_q = "PASS";
+            return function(o_p) {
+                if (!o_p$0) return o_p;
+            }(o_q);
+        }());
+    }
+    expect_stdout: "PASS"
+}
+
 contains_this_1: {
    options = {
        evaluate: true,
--- a/test/compress/ie8.js
+++ b/test/compress/ie8.js
@@ -2877,3 +2877,30 @@ issue_4235: {
    }
    expect_stdout: "undefined"
 }
+
+issue_4250: {
+    options = {
+        ie8: true,
+        loops: true,
+        unused: true,
+    }
+    input: {
+        console.log(function f() {
+            (function() {
+                for (f in "f");
+            })();
+            return f;
+            var f;
+        }());
+    }
+    expect: {
+        console.log(function f() {
+            (function() {
+                for (f in "f");
+            })();
+            return f;
+            var f;
+        }());
+    }
+    expect_stdout: "0"
+}
--- a/test/compress/issue-1034.js
+++ b/test/compress/issue-1034.js
@@ -39,7 +39,7 @@ non_hoisted_function_after_return: {
        "WARN: Dropping unreachable code [test/compress/issue-1034.js:4,16]",
        "WARN: Dropping unreachable code [test/compress/issue-1034.js:7,16]",
        "WARN: Dropping unreachable code [test/compress/issue-1034.js:10,12]",
-        "WARN: Dropping unused function UnusedFunction [test/compress/issue-1034.js:11,21]"
+        "WARN: Dropping unused function UnusedFunction [test/compress/issue-1034.js:11,21]",
    ]
 }

@@ -84,15 +84,12 @@ non_hoisted_function_after_return_2a: {
        }
    }
    expect_warnings: [
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:4,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:4,16]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:7,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:7,16]",
+        "WARN: Dropping initialization in unreachable code [test/compress/issue-1034.js:4,16]",
+        "WARN: Dropping initialization in unreachable code [test/compress/issue-1034.js:7,16]",
        "WARN: Dropping unused variable a [test/compress/issue-1034.js:4,20]",
        "WARN: Dropping unused function nope [test/compress/issue-1034.js:11,21]",
        "INFO: pass 0: last_count: Infinity, count: 35",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:9,12]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:9,12]",
+        "WARN: Dropping initialization in unreachable code [test/compress/issue-1034.js:9,12]",
        "WARN: Dropping unreachable code [test/compress/issue-1034.js:12,12]",
        "INFO: Dropping unused variable b [test/compress/issue-1034.js:7,20]",
        "INFO: Dropping unused variable c [test/compress/issue-1034.js:9,16]",
@@ -138,10 +135,7 @@ non_hoisted_function_after_return_2b: {
        }
    }
    expect_warnings: [
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:6,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:6,16]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:8,12]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:8,12]",
+        "WARN: Dropping initialization in unreachable code [test/compress/issue-1034.js:8,12]",
        "WARN: Dropping unreachable code [test/compress/issue-1034.js:12,12]",
    ]
 }
@@ -242,15 +236,12 @@ non_hoisted_function_after_return_2a_strict: {
    }
    expect_stdout: "5 6"
    expect_warnings: [
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:5,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:5,16]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:8,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:8,16]",
+        "WARN: Dropping initialization in unreachable code [test/compress/issue-1034.js:5,16]",
+        "WARN: Dropping initialization in unreachable code [test/compress/issue-1034.js:8,16]",
        "WARN: Dropping unused variable a [test/compress/issue-1034.js:5,20]",
        "WARN: Dropping unused function nope [test/compress/issue-1034.js:12,21]",
        "INFO: pass 0: last_count: Infinity, count: 46",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:10,12]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:10,12]",
+        "WARN: Dropping initialization in unreachable code [test/compress/issue-1034.js:10,12]",
        "WARN: Dropping unreachable code [test/compress/issue-1034.js:13,12]",
        "INFO: Dropping unused variable b [test/compress/issue-1034.js:8,20]",
        "INFO: Dropping unused variable c [test/compress/issue-1034.js:10,16]",
@@ -301,10 +292,7 @@ non_hoisted_function_after_return_2b_strict: {
    }
    expect_stdout: "5 6"
    expect_warnings: [
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:7,16]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:7,16]",
-        "WARN: Dropping unreachable code [test/compress/issue-1034.js:9,12]",
-        "WARN: Declarations in unreachable code! [test/compress/issue-1034.js:9,12]",
+        "WARN: Dropping initialization in unreachable code [test/compress/issue-1034.js:9,12]",
        "WARN: Dropping unreachable code [test/compress/issue-1034.js:13,12]",
    ]
 }
--- a/test/compress/let.js
+++ b/test/compress/let.js
@@ -20,6 +20,26 @@ retain_block: {
    node_version: ">=4"
 }

+retain_catch: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        "use strict";
+        try {} catch (a) {
+            let a = "aa";
+        }
+    }
+    expect: {
+        "use strict";
+        try {} catch (a) {
+            let a = "aa";
+        }
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
 if_dead_branch: {
    options = {
        conditionals: true,
@@ -893,3 +913,318 @@ issue_4231: {
    expect_stdout: "function"
    node_version: ">=4"
 }
+
+issue_4245: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        "use strict";
+        let a = f();
+        function f() {
+            typeof a;
+        }
+    }
+    expect: {
+        "use strict";
+        let a = f();
+        function f() {
+            a,
+            1;
+        }
+    }
+    expect_stdout: ReferenceError("a is not defined")
+    node_version: ">=4"
+}
+
+issue_4248: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            (function() {
+                "use strict";
+                a = "PASS";
+                b[a];
+                let b;
+            })();
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect: {
+        var a = "FAIL";
+        try {
+            (function() {
+                "use strict";
+                a = "PASS";
+                b[a];
+                let b;
+            })();
+        } catch (e) {
+            console.log(a);
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4274_1: {
+    options = {
+        loops: true,
+    }
+    input: {
+        "use strict";
+        for (;;) {
+            if (console.log("PASS")) {
+                let a;
+            } else {
+                break;
+                var a;
+            }
+        }
+    }
+    expect: {
+        "use strict";
+        for (; console.log("PASS");) {
+            {
+                let a;
+            }
+            var a;
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4274_2: {
+    options = {
+        loops: true,
+    }
+    input: {
+        "use strict";
+        for (;;) {
+            if (!console.log("PASS")) {
+                break;
+                var a;
+            } else {
+                let a;
+            }
+        }
+    }
+    expect: {
+        "use strict";
+        for (; console.log("PASS");) {
+            {
+                let a;
+            }
+            var a;
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4276_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        "use strict";
+        try {
+            let a = b, b;
+            console.log("FAIL");
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            let a = b, b;
+            console.log("FAIL");
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4276_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        "use strict";
+        try {
+            let a = f(), b;
+            console.log("FAIL");
+            function f() {
+                return b;
+            }
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            let a = f(), b;
+            console.log("FAIL");
+            function f() {
+                return b;
+            }
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4290_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        "use strict";
+        let a;
+        var a;
+    }
+    expect: {
+        "use strict";
+        let a;
+        var a;
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+issue_4290_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        "use strict";
+        try {
+            console.log(function(a) {
+                a = c;
+                let c;
+                return a;
+            }());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        "use strict";
+        try {
+            console.log(function(a) {
+                a = c;
+                let c;
+                return a;
+            }());
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4305_1: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            let arguments = function() {
+                while (console.log("PASS"));
+            };
+            arguments();
+        })();
+    }
+    expect: {
+        (function() {
+            let arguments = function() {
+                while (console.log("PASS"));
+            };
+            arguments();
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+issue_4305_2: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        (function(a) {
+            let a = function() {
+                while (console.log("aaaaa"));
+            };
+            a();
+        })();
+    }
+    expect: {
+        "use strict";
+        (function(a) {
+            let a = function() {
+                while (console.log("aaaaa"));
+            };
+            a();
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+issue_1753: {
+    mangle = {
+        toplevel: false,
+        webkit: true,
+    }
+    input: {
+        "use strict";
+        let l = null;
+        for (let i = 0; i < 1; i++)
+            console.log(i);
+    }
+    expect: {
+        "use strict";
+        let l = null;
+        for (let i = 0; i < 1; i++)
+            console.log(i);
+    }
+    expect_stdout: "0"
+    node_version: ">=4"
+}
+
+issue_1753_toplevel: {
+    mangle = {
+        toplevel: true,
+        webkit: true,
+    }
+    input: {
+        "use strict";
+        let l = null;
+        for (let i = 0; i < 1; i++)
+            console.log(i);
+    }
+    expect: {
+        "use strict";
+        let l = null;
+        for (let e = 0; e < 1; e++)
+            console.log(e);
+    }
+    expect_stdout: "0"
+    node_version: ">=4"
+}
--- a/test/compress/merge_vars.js
+++ b/test/compress/merge_vars.js
@@ -3092,3 +3092,94 @@ issue_4237_2: {
    }
    expect_stdout: "PASS"
 }
+
+issue_4253: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        switch (0) {
+          default:
+            var a = "FAIL";
+            a = a && a;
+            try {
+                break;
+            } catch (e) {}
+            var b = 42;
+        }
+        console.log(b);
+    }
+    expect: {
+        switch (0) {
+          default:
+            var a = "FAIL";
+            a = a && a;
+            try {
+                break;
+            } catch (e) {}
+            var b = 42;
+        }
+        console.log(b);
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4255: {
+    options = {
+        dead_code: true,
+        loops: true,
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        L: for (var a = 2; --a;)
+            for (var b = 0; console.log(b); --b)
+                break L;
+    }
+    expect: {
+        L: for (var a = 2; --a;) {
+            var b = 0;
+            if (console.log(b))
+                break L;
+        }
+    }
+    expect_stdout: "0"
+}
+
+issue_4257: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 0;
+        for (var i = 0; i < 2; i++)
+            switch (--a) {
+              case 0:
+                var b = 0;
+                break;
+              case 0:
+              default:
+                var c = 1 + (0 | (b && A));
+                console.log(c);
+            }
+    }
+    expect: {
+        var a = 0;
+        for (var i = 0; i < 2; i++)
+            switch (--a) {
+              case 0:
+                var b = 0;
+                break;
+              case 0:
+              default:
+                var c = 1 + (0 | (b && A));
+                console.log(c);
+            }
+    }
+    expect_stdout: [
+        "1",
+        "1",
+    ]
+}
--- a/test/compress/numbers.js
+++ b/test/compress/numbers.js
@@ -1,49 +1,100 @@
-hex_numbers_in_parentheses_for_prototype_functions: {
+parentheses_for_prototype_functions: {
    beautify = {
        beautify: true,
    }
    input: {
-        function f() {
-            (-2);
-            (-2).toFixed(0);
+        (function() {
+            console.log((-2));
+            console.log((-2).toFixed(0));

-            (2);
-            (2).toFixed(0);
+            console.log((2));
+            console.log((2).toFixed(0));

-            (0.2);
-            (0.2).toFixed(0);
+            console.log((0.2));
+            console.log((0.2).toFixed(0));

-            (2.34e20);
-            (2.34e20).toFixed(0);
+            console.log((2.34e20));
+            console.log((2.34e20).toFixed(0));

-            (0.00000002);
-            (0.00000002).toFixed(0);
+            console.log((0.00000002));
+            console.log((0.00000002).toFixed(0));

-            (1000000000000000128);
-            (1000000000000000128).toFixed(0);
+            console.log((1000000000000000128));
+            console.log((1000000000000000128).toFixed(0));

-            (-1000000000000000128);
-            (-1000000000000000128).toFixed(0);
-        }
+            console.log((-1000000000000000128));
+            console.log((-1000000000000000128).toFixed(0));
+        })();
    }
    expect_exact: [
-        "function f() {",
-        "    -2;",
-        "    (-2).toFixed(0);",
-        "    2;",
-        "    2..toFixed(0);",
-        "    .2;",
-        "    .2.toFixed(0);",
-        "    234e18;",
-        "    234e18.toFixed(0);",
-        "    2e-8;",
-        "    2e-8.toFixed(0);",
-        "    0xde0b6b3a7640080;",
-        "    (0xde0b6b3a7640080).toFixed(0);",
-        "    -0xde0b6b3a7640080;",
-        "    (-0xde0b6b3a7640080).toFixed(0);",
-        "}",
+        "(function() {",
+        "    console.log(-2);",
+        "    console.log((-2).toFixed(0));",
+        "    console.log(2);",
+        "    console.log(2..toFixed(0));",
+        "    console.log(.2);",
+        "    console.log(.2.toFixed(0));",
+        "    console.log(234e18);",
+        "    console.log(234e18.toFixed(0));",
+        "    console.log(2e-8);",
+        "    console.log(2e-8.toFixed(0));",
+        "    console.log(0xde0b6b3a7640080);",
+        "    console.log(0xde0b6b3a7640080.toFixed(0));",
+        "    console.log(-0xde0b6b3a7640080);",
+        "    console.log((-0xde0b6b3a7640080).toFixed(0));",
+        "})();",
    ]
+    expect_stdout: true
+}
+
+parentheses_for_prototype_functions_galio: {
+    beautify = {
+        beautify: true,
+        galio: true,
+    }
+    input: {
+        (function() {
+            console.log((-2));
+            console.log((-2).toFixed(0));
+
+            console.log((2));
+            console.log((2).toFixed(0));
+
+            console.log((0.2));
+            console.log((0.2).toFixed(0));
+
+            console.log((2.34e20));
+            console.log((2.34e20).toFixed(0));
+
+            console.log((0.00000002));
+            console.log((0.00000002).toFixed(0));
+
+            console.log((1000000000000000128));
+            console.log((1000000000000000128).toFixed(0));
+
+            console.log((-1000000000000000128));
+            console.log((-1000000000000000128).toFixed(0));
+        })();
+    }
+    expect_exact: [
+        "(function() {",
+        "    console.log(-2);",
+        "    console.log((-2).toFixed(0));",
+        "    console.log(2);",
+        "    console.log(2..toFixed(0));",
+        "    console.log(.2);",
+        "    console.log(.2.toFixed(0));",
+        "    console.log(234e18);",
+        "    console.log(234e18.toFixed(0));",
+        "    console.log(2e-8);",
+        "    console.log(2e-8.toFixed(0));",
+        "    console.log(0xde0b6b3a7640080);",
+        "    console.log((0xde0b6b3a7640080).toFixed(0));",
+        "    console.log(-0xde0b6b3a7640080);",
+        "    console.log((-0xde0b6b3a7640080).toFixed(0));",
+        "})();",
+    ]
+    expect_stdout: true
 }

 comparisons: {
--- a/test/compress/objects.js
+++ b/test/compress/objects.js
@@ -221,3 +221,142 @@ numeric_literal: {
        "8 7 8",
    ]
 }
+
+evaluate_computed_key: {
+    options = {
+        evaluate: true,
+        objects: true,
+    }
+    input: {
+        console.log({
+            ["foo" + "bar"]: "PASS",
+        }.foobar);
+    }
+    expect: {
+        console.log({
+            foobar: "PASS",
+        }.foobar);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+keep_computed_key: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        ({
+            [console.log("PASS")]: 42,
+        });
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4269_1: {
+    options = {
+        evaluate: true,
+        objects: true,
+    }
+    input: {
+        console.log({
+            get 0() {
+                return "FAIL";
+            },
+            [0]: "PASS",
+        }[0]);
+    }
+    expect: {
+        console.log({
+            get 0() {
+                return "FAIL";
+            },
+            [0]: "PASS",
+        }[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4269_2: {
+    options = {
+        evaluate: true,
+        objects: true,
+    }
+    input: {
+        console.log({
+            get [0]() {
+                return "FAIL";
+            },
+            0: "PASS",
+        }[0]);
+    }
+    expect: {
+        console.log({
+            get [0]() {
+                return "FAIL";
+            },
+            0: "PASS",
+        }[0]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4269_3: {
+    options = {
+        evaluate: true,
+        objects: true,
+    }
+    input: {
+        console.log({
+            ["foo"]: "bar",
+            get 42() {
+                return "FAIL";
+            },
+            42: "PASS",
+        }[42]);
+    }
+    expect: {
+        console.log({
+            ["foo"]: "bar",
+            get 42() {
+                return "FAIL";
+            },
+            42: "PASS",
+        }[42]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_4269_4: {
+    options = {
+        evaluate: true,
+        objects: true,
+    }
+    input: {
+        console.log({
+            get 42() {
+                return "FAIL";
+            },
+            ["foo"]: "bar",
+            42: "PASS",
+        }[42]);
+    }
+    expect: {
+        console.log({
+            get 42() {
+                return "FAIL";
+            },
+            ["foo"]: "bar",
+            42: "PASS",
+        }[42]);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -1999,7 +1999,7 @@ issue_1606: {
            var a, b;
            function g(){};
            b = 2;
-            x(b);
+            x(2);
        }
    }
 }
--- a/test/compress/varify.js
+++ b/test/compress/varify.js
@@ -234,3 +234,178 @@ issue_4191_let: {
    expect_stdout: "function undefined"
    node_version: ">=4"
 }
+
+forin_const_1: {
+    options = {
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        varify: true,
+    }
+    input: {
+        const o = {
+            foo: 42,
+            bar: "PASS",
+        };
+        for (const k in o)
+            console.log(k, o[k]);
+    }
+    expect: {
+        var o = {
+            foo: 42,
+            bar: "PASS",
+        };
+        for (const k in o)
+            console.log(k, o[k]);
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+forin_const_2: {
+    options = {
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        varify: true,
+    }
+    input: {
+        const o = {
+            p: 42,
+            q: "PASS",
+        };
+        for (const [ k ] in o)
+            console.log(k, o[k]);
+    }
+    expect: {
+        var o = {
+            p: 42,
+            q: "PASS",
+        }, k;
+        for ([ k ] in o)
+            console.log(k, o[k]);
+    }
+    expect_stdout: [
+        "p 42",
+        "q PASS",
+    ]
+    node_version: ">=6"
+}
+
+forin_let_1: {
+    options = {
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        varify: true,
+    }
+    input: {
+        "use strict";
+        let o = {
+            foo: 42,
+            bar: "PASS",
+        };
+        for (let k in o)
+            console.log(k, o[k]);
+    }
+    expect: {
+        "use strict";
+        var o = {
+            foo: 42,
+            bar: "PASS",
+        }, k;
+        for (k in o)
+            console.log(k, o[k]);
+    }
+    expect_stdout: [
+        "foo 42",
+        "bar PASS",
+    ]
+    node_version: ">=4"
+}
+
+forin_let_2: {
+    options = {
+        join_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        varify: true,
+    }
+    input: {
+        let o = {
+            p: 42,
+            q: "PASS",
+        };
+        for (let [ k ] in o)
+            console.log(k, o[k]);
+    }
+    expect: {
+        var o = {
+            p: 42,
+            q: "PASS",
+        }, k;
+        for ([ k ] in o)
+            console.log(k, o[k]);
+    }
+    expect_stdout: [
+        "p 42",
+        "q PASS",
+    ]
+    node_version: ">=6"
+}
+
+issue_4290_1_const: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        varify: true,
+    }
+    input: {
+        const a = 0;
+        var a;
+    }
+    expect: {
+        const a = 0;
+        var a;
+    }
+    expect_stdout: true
+}
+
+issue_4290_1_let: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        varify: true,
+    }
+    input: {
+        "use strict";
+        let a = 0;
+        var a;
+    }
+    expect: {
+        "use strict";
+        let a = 0;
+        var a;
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+drop_forin_let: {
+    options = {
+        loops: true,
+        toplevel: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        "use strict";
+        for (let a in console.log("PASS"));
+    }
+    expect: {
+        "use strict";
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
--- a/test/mocha/tokens.js
+++ b/test/mocha/tokens.js
@@ -5,7 +5,7 @@ describe("tokens", function() {
    it("Should give correct positions for accessors", function() {
        // location               0         1         2         3         4
        //                        01234567890123456789012345678901234567890123456789
-        var ast = UglifyJS.parse("var obj = { get latest() { return undefined; } }");
+        var ast = UglifyJS.parse("var obj = { get [prop]() { return undefined; } }");
        // test all AST_ObjectProperty tokens are set as expected
        var found = false;
        ast.walk(new UglifyJS.TreeWalker(function(node) {
@@ -13,9 +13,9 @@ describe("tokens", function() {
                found = true;
                assert.equal(node.start.pos, 12);
                assert.equal(node.end.endpos, 46);
-                assert(node.key instanceof UglifyJS.AST_SymbolAccessor);
-                assert.equal(node.key.start.pos, 16);
-                assert.equal(node.key.end.endpos, 22);
+                assert(node.key instanceof UglifyJS.AST_SymbolRef);
+                assert.equal(node.key.start.pos, 17);
+                assert.equal(node.key.end.endpos, 21);
                assert(node.value instanceof UglifyJS.AST_Accessor);
                assert.equal(node.value.start.pos, 22);
                assert.equal(node.value.end.endpos, 46);
--- a/test/reduce.js
+++ b/test/reduce.js
@@ -95,6 +95,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)

            // quick ignores
            if (node instanceof U.AST_Accessor) return;
+            if (node instanceof U.AST_Destructured) return;
            if (node instanceof U.AST_Directive) return;
            if (!in_list && node instanceof U.AST_EmptyStatement) return;
            if (node instanceof U.AST_Label) return;
@@ -114,6 +115,8 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)

            // ignore lvalues
            if (parent instanceof U.AST_Assign && parent.left === node) return;
+            if (parent instanceof U.AST_DestructuredArray) return;
+            if (parent instanceof U.AST_DestructuredKeyVal && parent.value === node) return;
            if (parent instanceof U.AST_Unary && parent.expression === node) switch (parent.operator) {
              case "++":
              case "--":
@@ -250,13 +253,23 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                }
            }
            else if (node instanceof U.AST_ForIn) {
-                var expr = [
-                    node.init,
-                    node.object,
-                    node.body,
-                ][ (node.start._permute * steps | 0) % 3 ];
+                var expr;
+                switch ((node.start._permute * steps | 0) % 3) {
+                  case 0:
+                    if (!(node.init instanceof U.AST_Definitions
+                        && node.init.definitions[0].name instanceof U.AST_Destructured)) {
+                        expr = node.init;
+                    }
+                    break;
+                  case 1:
+                    expr = node.object;
+                    break;
+                  case 2:
+                    if (!has_loopcontrol(node.body, node, parent)) expr = node.body;
+                    break;
+                }
                node.start._permute += step;
-                if (expr && (expr !== node.body || !has_loopcontrol(expr, node, parent))) {
+                if (expr) {
                    CHANGED = true;
                    return to_statement(expr);
                }
@@ -389,6 +402,13 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                    CHANGED = true;
                    return List.skip;
                }
+
+                // skip element/property from (destructured) array/object
+                if (parent instanceof U.AST_Array || parent instanceof U.AST_Destructured || parent instanceof AST_Object) {
+                    node.start._permute++;
+                    CHANGED = true;
+                    return List.skip;
+                }
            }

            // replace this node
@@ -593,7 +613,7 @@ function is_error(result) {
 }

 function is_timed_out(result) {
-    return is_error(result) && /timed out/.test(result);
+    return is_error(result) && /timed out/.test(result.message);
 }

 function is_statement(node) {
--- a/test/ufuzz/index.js
+++ b/test/ufuzz/index.js
@@ -276,6 +276,7 @@ var NO_DEFUN = false;
 var DEFUN_OK = true;
 var DONT_STORE = true;
 var NO_CONST = true;
+var NO_DUPLICATE = true;

 var VAR_NAMES = [
    "a",
@@ -356,11 +357,15 @@ function createFunctions(n, recurmax, allowDefun, canThrow, stmtDepth) {
    return s;
 }

-function createParams() {
+function createParams(noDuplicate) {
+    var len = unique_vars.length;
    var params = [];
    for (var n = rng(4); --n >= 0;) {
-        params.push(createVarName(MANDATORY));
+        var name = createVarName(MANDATORY);
+        if (noDuplicate) unique_vars.push(name);
+        params.push(name);
    }
+    unique_vars.length = len;
    return params.join(", ");
 }

@@ -372,6 +377,118 @@ function createArgs(recurmax, stmtDepth, canThrow) {
    return args.join(", ");
 }

+function createAssignmentPairs(recurmax, noComma, stmtDepth, canThrow, varNames, maybe, dontStore) {
+    var avoid = [];
+    var len = unique_vars.length;
+    var pairs = createPairs(recurmax);
+    unique_vars.length = len;
+    return pairs;
+
+    function createAssignmentValue(recurmax) {
+        var current = VAR_NAMES;
+        VAR_NAMES = (varNames || VAR_NAMES).slice();
+        var value = varNames && rng(2) ? createValue() : createExpression(recurmax, noComma, stmtDepth, canThrow);
+        VAR_NAMES = current;
+        return value;
+    }
+
+    function createKey(recurmax, keys) {
+        var save = VAR_NAMES;
+        VAR_NAMES = VAR_NAMES.filter(function(name) {
+            return avoid.indexOf(name) < 0;
+        });
+        var len = VAR_NAMES.length;
+        var key;
+        do {
+            key = createObjectKey(recurmax, stmtDepth, canThrow);
+        } while (keys.indexOf(key) >= 0);
+        VAR_NAMES = save.concat(VAR_NAMES.slice(len));
+        return key;
+    }
+
+    function createPairs(recurmax) {
+        var names = [], values = [];
+        var m = rng(4), n = rng(4);
+        if (!varNames) m = Math.max(m, n, 1);
+        for (var i = Math.max(m, n); --i >= 0;) {
+            if (i < m && i < n) {
+                createDestructured(recurmax, names, values);
+                continue;
+            }
+            if (i < m) {
+                unique_vars.push("a", "b", "c", "undefined", "NaN", "Infinity");
+                var name = createVarName(maybe, dontStore);
+                unique_vars.length -= 6;
+                avoid.push(name);
+                unique_vars.push(name);
+                names.unshift(name);
+            }
+            if (i < n) {
+                values.unshift(createAssignmentValue(recurmax));
+            }
+        }
+        return {
+            names: names,
+            values: values,
+        };
+    }
+
+    function createDestructured(recurmax, names, values) {
+        switch (rng(20)) {
+          case 0:
+            if (--recurmax < 0) {
+                names.unshift("[]");
+                values.unshift('""');
+            } else {
+                var pairs = createPairs(recurmax);
+                while (!rng(10)) {
+                    var index = rng(pairs.names.length + 1);
+                    pairs.names.splice(index, 0, "");
+                    pairs.values.splice(index, 0, rng(2) ? createAssignmentValue(recurmax) : "");
+                }
+                names.unshift("[ " + pairs.names.join(", ") + " ]");
+                values.unshift("[ " + pairs.values.join(", ") + " ]");
+            }
+            break;
+          case 1:
+            if (--recurmax < 0) {
+                names.unshift("{}");
+                values.unshift('""');
+            } else {
+                var pairs = createPairs(recurmax);
+                var keys = [];
+                pairs.names.forEach(function(name, index) {
+                    if (/^[[{]/.test(name)) {
+                        var key;
+                        do {
+                            key = KEYS[rng(KEYS.length)];
+                        } while (keys.indexOf(key) >= 0);
+                        keys[index] = key;
+                    }
+                });
+                names.unshift("{ " + pairs.names.map(function(name, index) {
+                    var key = index in keys ? keys[index] : rng(10) && createKey(recurmax, keys);
+                    return key ? key + ": " + name : name;
+                }).join(", ") + " }");
+                values.unshift("{ " + pairs.values.map(function(value, index) {
+                    var key = index in keys ? keys[index] : createKey(recurmax, keys);
+                    return key + ": " + value;
+                }).join(", ") + " }");
+            }
+            break;
+          default:
+            unique_vars.push("a", "b", "c", "undefined", "NaN", "Infinity");
+            var name = createVarName(maybe, dontStore);
+            unique_vars.length -= 6;
+            avoid.push(name);
+            unique_vars.push(name);
+            names.unshift(name);
+            values.unshift(createAssignmentValue(recurmax));
+            break;
+        }
+    }
+}
+
 function filterDirective(s) {
    if (!generate_directive && !s[1] && /\("/.test(s[2])) s[2] = ";" + s[2];
    return s;
@@ -410,11 +527,37 @@ function createBlockVariables(recurmax, stmtDepth, canThrow, fn) {
            return names.indexOf(name) < 0;
        });
        var len = VAR_NAMES.length;
-        var s = type + " " + names.map(function(name) {
-            var value = createExpression(recurmax, NO_COMMA, stmtDepth, canThrow);
-            VAR_NAMES.push(name);
-            return name + " = " + value;
-        }).join(", ") + ";";
+        var s = type + " ";
+        switch (rng(10)) {
+          case 0:
+            while (!rng(10)) names.splice(rng(names.length + 1), 0, "");
+            s += "[ " + names.join(", ") + " ] = [ " + names.map(function() {
+                return rng(10) ? createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) : "";
+            }).join(", ") + " ];";
+            break;
+          case 1:
+            var keys = [];
+            s += "{ " + names.map(function(name, i) {
+                var key = createObjectKey(recurmax, stmtDepth, canThrow);
+                if (!/\[/.test(key)) keys[i] = key;
+                return key + ": " + name;
+            }).join(", ") + "} = { " + names.map(function(name, i) {
+                var key = i in keys ? keys[i] : createObjectKey(recurmax, stmtDepth, canThrow);
+                return key + ": " + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow);
+            }).join(", ") + "};";
+            break;
+          default:
+            s += names.map(function(name, i) {
+                if (type == "let" && !rng(10)) {
+                    VAR_NAMES.push(name);
+                    return name;
+                }
+                var value = createExpression(recurmax, NO_COMMA, stmtDepth, canThrow);
+                VAR_NAMES.push(name);
+                return name + " = " + value;
+            }).join(", ") + ";";
+            break;
+        }
        VAR_NAMES = save.concat(VAR_NAMES.slice(len));
        return s;
    }
@@ -424,9 +567,9 @@ function createFunction(recurmax, allowDefun, canThrow, stmtDepth) {
    if (--recurmax < 0) { return ";"; }
    if (!STMT_COUNT_FROM_GLOBAL) stmtDepth = 0;
    var s = [];
-    var name;
+    var name, args;
+    var varNames = VAR_NAMES.slice();
    createBlockVariables(recurmax, stmtDepth, canThrow, function(defns) {
-        var namesLenBefore = VAR_NAMES.length;
        if (allowDefun || rng(5) > 0) {
            name = "f" + funcs++;
        } else {
@@ -434,7 +577,16 @@ function createFunction(recurmax, allowDefun, canThrow, stmtDepth) {
            name = createVarName(MANDATORY, !allowDefun);
            unique_vars.length -= 3;
        }
-        s.push("function " + name + "(" + createParams() + "){", strictMode());
+        var params;
+        if ((!allowDefun || !(name in called)) && rng(2)) {
+            called[name] = false;
+            var pairs = createAssignmentPairs(recurmax, COMMA_OK, stmtDepth, canThrow, varNames, MANDATORY);
+            params = pairs.names.join(", ");
+            args = pairs.values.join(", ");
+        } else {
+            params = createParams();
+        }
+        s.push("function " + name + "(" + params + "){", strictMode());
        s.push(defns());
        if (rng(5) === 0) {
            // functions with functions. lower the recursion to prevent a mess.
@@ -445,17 +597,16 @@ function createFunction(recurmax, allowDefun, canThrow, stmtDepth) {
        }
        s.push("}", "");
        s = filterDirective(s).join("\n");
-
-        VAR_NAMES.length = namesLenBefore;
    });
+    VAR_NAMES = varNames;

    if (!allowDefun) {
        // avoid "function statements" (decl inside statements)
        s = "var " + createVarName(MANDATORY) + " = " + s;
-        s += "(" + createArgs(recurmax, stmtDepth, canThrow) + ")";
-    } else if (!(name in called) || rng(3) > 0) {
+        s += "(" + (args || createArgs(recurmax, stmtDepth, canThrow)) + ")";
+    } else if (!(name in called) || args || rng(3)) {
        s += "var " + createVarName(MANDATORY) + " = " + name;
-        s += "(" + createArgs(recurmax, stmtDepth, canThrow) + ")";
+        s += "(" + (args || createArgs(recurmax, stmtDepth, canThrow)) + ")";
    }

    return s + ";";
@@ -556,8 +707,9 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
        return [
            "{var expr" + loop + " = " + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "; ",
            label.target + " for (",
-            /^key/.test(key) ? "var " : "",
-            key + " in expr" + loop + ") {",
+            !/^key/.test(key) ? rng(10) ? "" : "var " : rng(10) ? "var " : rng(2) ? "let " : "const ",
+            rng(10) ? key : rng(5) ? "[ " + key + " ]" : "{ length: " + key + " }",
+            " in expr" + loop + ") {",
            rng(5) > 1 ? "c = 1 + c; var " + createVarName(MANDATORY) + " = expr" + loop + "[" + key + "]; " : "",
            createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth),
            "}}",
@@ -571,7 +723,12 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
        // note: default does not _need_ to be last
        return "switch (" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ") { " + createSwitchParts(recurmax, 4, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + "}";
      case STMT_VAR:
-        switch (rng(3)) {
+        if (!rng(20)) {
+            var pairs = createAssignmentPairs(recurmax, NO_COMMA, stmtDepth, canThrow, null, MANDATORY);
+            return "var " + pairs.names.map(function(name, index) {
+                return index in pairs.values ? name + " = " + pairs.values[index] : name;
+            }).join(", ") + ";";
+        } else switch (rng(3)) {
          case 0:
            unique_vars.push("c");
            var name = createVarName(MANDATORY);
@@ -714,7 +871,28 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
      case p++:
        return getVarName();
      case p++:
-        return getVarName(NO_CONST) + createAssignment() + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow);
+        switch (rng(20)) {
+          case 0:
+            return [
+                "[ ",
+                new Array(rng(3)).join(","),
+                getVarName(NO_CONST),
+                new Array(rng(3)).join(","),
+                " ] = ",
+                createArrayLiteral(recurmax, stmtDepth, canThrow),
+            ].join("");
+          case 1:
+            return [
+                "{ ",
+                rng(2) ? "" : createObjectKey(recurmax, stmtDepth, canThrow) + ": ",
+                getVarName(NO_CONST),
+                " } = ",
+                createExpression(recurmax, COMMA_OK, stmtDepth, canThrow),
+                " || {}",
+            ].join("");
+          default:
+            return getVarName(NO_CONST) + createAssignment() + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow);
+        }
      case p++:
        return createExpression(recurmax, COMMA_OK, stmtDepth, canThrow);
      case p++:
@@ -859,7 +1037,10 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
      case p++:
      case p++:
      case p++:
-        var name = rng(3) == 0 ? getVarName() : "f" + rng(funcs + 2);
+        var name;
+        do {
+            name = rng(3) == 0 ? getVarName() : "f" + rng(funcs + 2);
+        } while (name in called && !called[name]);
        called[name] = true;
        return "typeof " + name + ' == "function" && --_calls_ >= 0 && ' + name + "(" + createArgs(recurmax, stmtDepth, canThrow) + ")";
    }
@@ -908,21 +1089,27 @@ function getDotKey(assign) {
    return key;
 }

-function createAccessor(recurmax, stmtDepth, canThrow) {
+function createObjectKey(recurmax, stmtDepth, canThrow) {
+    return rng(10) ? KEYS[rng(KEYS.length)] : "[" + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + "]";
+}
+
+function createObjectFunction(recurmax, stmtDepth, canThrow) {
    var namesLenBefore = VAR_NAMES.length;
    var s;
    createBlockVariables(recurmax, stmtDepth, canThrow, function(defns) {
-        var prop1 = getDotKey();
-        if (rng(2) == 0) {
+        switch (rng(3)) {
+          case 0:
            s = [
-                "get " + prop1 + "(){",
+                "get " + createObjectKey(recurmax, stmtDepth, canThrow) + "(){",
                strictMode(),
                defns(),
                _createStatements(2, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
                createStatement(recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth, STMT_RETURN_ETC),
-                "},"
+                "},",
            ];
-        } else {
+            break;
+          case 1:
+            var prop1 = createObjectKey(recurmax, stmtDepth, canThrow);
            var prop2;
            do {
                prop2 = getDotKey();
@@ -933,8 +1120,18 @@ function createAccessor(recurmax, stmtDepth, canThrow) {
                defns(),
                _createStatements(2, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
                "this." + prop2 + createAssignment() + _createBinaryExpr(recurmax, COMMA_OK, stmtDepth, canThrow) + ";",
-                "},"
+                "},",
            ];
+            break;
+          default:
+            s = [
+                createObjectKey(recurmax, stmtDepth, canThrow) + "(" + createParams(NO_DUPLICATE) + "){",
+                strictMode(),
+                defns(),
+                _createStatements(3, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
+                "},",
+            ]
+            break;
        }
    });
    VAR_NAMES.length = namesLenBefore;
@@ -944,13 +1141,16 @@ function createAccessor(recurmax, stmtDepth, canThrow) {
 function createObjectLiteral(recurmax, stmtDepth, canThrow) {
    recurmax--;
    var obj = ["({"];
-    for (var i = rng(6); --i >= 0;) {
-        if (rng(20) == 0) {
-            obj.push(createAccessor(recurmax, stmtDepth, canThrow));
-        } else {
-            var key = KEYS[rng(KEYS.length)];
-            obj.push(key + ":(" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "),");
-        }
+    for (var i = rng(6); --i >= 0;) switch (rng(30)) {
+      case 0:
+        obj.push(createObjectFunction(recurmax, stmtDepth, canThrow));
+        break;
+      case 1:
+        obj.push(getVarName() + ",");
+        break;
+      default:
+        obj.push(createObjectKey(recurmax, stmtDepth, canThrow) + ":(" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "),");
+        break;
    }
    obj.push("})");
    return obj.join("\n");
@@ -978,13 +1178,77 @@ function _createSimpleBinaryExpr(recurmax, noComma, stmtDepth, canThrow) {
        return "(" + assignee + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ")";
      case 3:
        assignee = getVarName();
-        expr = "(" + assignee + "[" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow)
-            + "]" + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ")";
+        switch (rng(20)) {
+          case 0:
+            expr = [
+                "([ ",
+                assignee,
+                "[", createExpression(recurmax, COMMA_OK, stmtDepth, canThrow), "]",
+                " ] = [ ",
+                _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow),
+                " ])",
+            ].join("");
+            break;
+          case 1:
+            var key1 = createObjectKey(recurmax, stmtDepth, canThrow);
+            var key2 = /^\[/.test(key1) ? createObjectKey(recurmax, stmtDepth, canThrow) : key1;
+            expr = [
+                "({ ",
+                key1, ": ", assignee,
+                "[", createExpression(recurmax, COMMA_OK, stmtDepth, canThrow), "]",
+                " } = { ",
+                key2, ": ", _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow),
+                " })",
+            ].join("");
+            break;
+          default:
+            expr = [
+                "(",
+                assignee,
+                "[", createExpression(recurmax, COMMA_OK, stmtDepth, canThrow), "]",
+                createAssignment(),
+                _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow),
+                ")",
+            ].join("");
+            break;
+        }
        return canThrow && rng(10) == 0 ? expr : "(" + assignee + " && " + expr + ")";
      case 4:
        assignee = getVarName();
-        expr = "(" + assignee + "." + getDotKey(true) + createAssignment()
-            + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ")";
+        switch (rng(20)) {
+          case 0:
+            expr = [
+                "([ ",
+                assignee,
+                ".", getDotKey(true),
+                " ] = [ ",
+                _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow),
+                " ])",
+            ].join("");
+            break;
+          case 1:
+            var key1 = createObjectKey(recurmax, stmtDepth, canThrow);
+            var key2 = /^\[/.test(key1) ? createObjectKey(recurmax, stmtDepth, canThrow) : key1;
+            expr = [
+                "({ ",
+                key1, ": ", assignee,
+                ".", getDotKey(true),
+                " } = { ",
+                key2, ": ", _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow),
+                " })",
+            ].join("");
+            break;
+          default:
+            expr = [
+                "(",
+                assignee,
+                ".", getDotKey(true),
+                createAssignment(),
+                _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow),
+                ")",
+            ].join("");
+            break;
+        }
        return canThrow && rng(10) == 0 ? expr : "(" + assignee + " && " + expr + ")";
      default:
        return _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow);
@@ -1327,7 +1591,14 @@ function patch_try_catch(orig, toplevel) {
    }
 }

-var minify_options = require("./options.json").map(JSON.stringify);
+var minify_options = require("./options.json");
+if (typeof sandbox.run_code("console.log([ 1 ], {} = 2);") != "string") {
+    minify_options.forEach(function(o) {
+        if (!("output" in o)) o.output = {};
+        o.output.v8 = true;
+    });
+}
+minify_options = minify_options.map(JSON.stringify);
 var original_code, original_result, errored;
 var uglify_code, uglify_result, ok;
 for (var round = 1; round <= num_iterations; round++) {
@@ -1369,7 +1640,12 @@ for (var round = 1; round <= num_iterations; round++) {
                }
            }
            // ignore difference in error message caused by Temporal Dead Zone
-            if (!ok && errored) ok = uglify_result.name == "ReferenceError" && original_result.name == "ReferenceError";
+            if (!ok && errored && uglify_result.name == "ReferenceError" && original_result.name == "ReferenceError") ok = true;
+            // ignore spurious time-outs
+            if (!ok && errored && /timed out/.test(original_result.message) && !/timed out/.test(uglify_result.message)) {
+                if (!orig_result[toplevel ? 3 : 2]) orig_result[toplevel ? 3 : 2] = sandbox.run_code(original_code, toplevel, 10000);
+                ok = sandbox.same_stdout(orig_result[toplevel ? 3 : 2], uglify_result);
+            }
            // ignore difference in error message caused by `in`
            // ignore difference in depth of termination caused by infinite recursion
            if (!ok) {
Author	SHA1	Message	Date
Alex Lam S.L	9f67866147	v3.12.0	2020-11-23 01:10:39 +08:00
Alex Lam S.L	645d5a348b	workaround Safari quirks (#4314 ) fixes #1753	2020-11-21 10:30:46 +08:00
Alex Lam S.L	cf120c7cea	fix corner case in `merge_vars` & `reduce_vars` (#4313 ) fixes #4312	2020-11-21 08:57:59 +08:00
Alex Lam S.L	8d30902ba9	fix corner case in `mangle` (#4311 )	2020-11-21 08:05:40 +08:00
Alex Lam S.L	02459cddf9	gate `galio` workaround (#4310 )	2020-11-21 03:37:33 +08:00
Alex Lam S.L	1b579779be	fix corner case in `collapse_vars` (#4309 ) fixes #4308	2020-11-20 06:23:37 +08:00
Alex Lam S.L	b18b70f63b	fix corner case in `hoist_props` (#4307 )	2020-11-20 00:02:25 +08:00
Alex Lam S.L	641406d491	fix corner cases in `reduce_vars` & `unused` (#4306 )	2020-11-19 11:25:36 +08:00
Alex Lam S.L	134ef0b1eb	fix corner case in `dead_code` (#4304 )	2020-11-19 08:34:55 +08:00
Alex Lam S.L	db87dcf13e	enhance `varify` (#4303 )	2020-11-19 07:58:33 +08:00
Alex Lam S.L	aecbabc587	fix corner case in `merge_vars` (#4302 ) fixes #4301	2020-11-19 05:44:47 +08:00
Alex Lam S.L	fd6544b340	fix corner case `reduce_vars` (#4300 ) fixes #4297	2020-11-19 01:11:28 +08:00
Alex Lam S.L	f6a83f7944	fix corner case in `merge_vars` (#4299 ) fixes #4298	2020-11-18 23:43:55 +08:00
Alex Lam S.L	35283e5dd1	enhance `arguments` (#4296 )	2020-11-18 11:39:32 +08:00
Alex Lam S.L	7a51c17ff0	fix corner case in `merge_vars` (#4295 ) fixes #4294	2020-11-18 09:32:53 +08:00
Alex Lam S.L	aff842f2f9	fix corner case in `arguments` (#4293 ) fixes #4291	2020-11-18 08:54:58 +08:00
Alex Lam S.L	0bedd031da	fix corner cases in `collapse_vars`, `unused` & `varify` (#4292 ) fixes #4290	2020-11-18 08:22:54 +08:00
Alex Lam S.L	caa92aea5d	fix corner case in `merge_vars` (#4289 ) fixes #4288	2020-11-18 04:03:20 +08:00
Alex Lam S.L	383163afa6	fix corner case in `collapse_vars` (#4287 ) fixes #4286	2020-11-17 18:03:31 +08:00
Alex Lam S.L	8a83c8dd46	fix corner cases in `collapse_vars` & `dead_code` (#4285 ) fixes #4284	2020-11-17 16:23:50 +08:00
Alex Lam S.L	2a612fd472	fix corner case in `reduce_vars` (#4283 ) fixes #4282	2020-11-17 14:43:04 +08:00
Alex Lam S.L	b9798a01a8	fix corner case in `reduce_vars` (#4281 ) fixes #4280	2020-11-17 12:59:44 +08:00
Alex Lam S.L	6dbacb5e3f	enhance `varify` (#4279 )	2020-11-17 12:35:00 +08:00
Alex Lam S.L	e5f80afc53	support destructured literals (#4278 )	2020-11-17 08:01:24 +08:00
Alex Lam S.L	42e34c870a	fix corner case in `unused` (#4277 ) fixes #4276	2020-11-17 02:06:00 +08:00
Alex Lam S.L	e390e7e124	v3.11.6	2020-11-14 22:21:19 +08:00
Alex Lam S.L	6fd5b5b371	fix corner case in `loops` (#4275 ) fixes #4274	2020-11-14 02:08:05 +08:00
Alex Lam S.L	fba27bfb71	fix corner case in `evaluate` (#4272 ) fixes #4271	2020-11-11 00:06:13 +08:00
Alex Lam S.L	41310e6404	fix corner case in `objects` (#4270 ) fixes #4269	2020-11-09 10:47:02 +08:00
Alex Lam S.L	91fc1c82b5	support computed property name in object literal (#4268 )	2020-11-08 23:38:32 +08:00
Alex Lam S.L	810cd40356	fix corner case in `inline` (#4266 ) fixes #4265	2020-11-08 18:50:08 +08:00
Alex Lam S.L	1cbd07e789	support shorthand method name in object literal (#4264 )	2020-11-08 13:17:53 +08:00
Alex Lam S.L	b82de04775	support shorthand property name in object literal (#4263 )	2020-11-08 10:44:44 +08:00
Alex Lam S.L	4bbeb09f7c	fix corner case in `reduce_vars` (#4262 ) fixes #4261	2020-11-07 10:00:04 +08:00
Alex Lam S.L	c2f6fd5fde	fix corner case in `functions` (#4260 ) fixes #4259	2020-11-06 03:55:25 +08:00
Alex Lam S.L	af4ea3ff69	v3.11.5	2020-11-03 08:59:02 +08:00
Alex Lam S.L	e7643248a3	fix corner case in `merge_vars` (#4258 ) fixes #4257	2020-11-02 01:01:00 +08:00
Alex Lam S.L	68091dbf69	fix corner case in `merge_vars` (#4256 ) fixes #4255	2020-11-01 14:34:07 +08:00
Alex Lam S.L	cbf7269296	fix corner case in `merge_vars` (#4254 ) fixes #4253	2020-11-01 10:37:21 +08:00
Alex Lam S.L	d8563caba7	improve resilience against spurious time-outs (#4252 )	2020-10-30 11:06:48 +08:00
Alex Lam S.L	2e0ad40fe6	fix corner case in `ie8` (#4251 ) fixes #4250	2020-10-30 11:06:31 +08:00
Alex Lam S.L	5d12abc41b	fix corner cases in `collapse_vars` (#4249 ) fixes #4248	2020-10-30 10:04:23 +08:00
Alex Lam S.L	79e5c3f564	improve warnings (#4247 ) closes #4244	2020-10-27 17:39:33 +08:00
Alex Lam S.L	607f87c5cd	fix corner case in `booleans` (#4246 ) fixes #4245	2020-10-26 18:53:58 +08:00