v3.11.3

fixes #4225

bin/uglifyjs

@@ -342,7 +342,18 @@ function run() {
         }
         fatal(ex);
     } else if (output == "ast") {
-        if (!options.compress && !options.mangle) result.ast.figure_out_scope({});
+        if (!options.compress && !options.mangle) {
+            var toplevel = result.ast;
+            if (!(toplevel instanceof UglifyJS.AST_Toplevel)) {
+                if (!(toplevel instanceof UglifyJS.AST_Statement)) toplevel = new UglifyJS.AST_SimpleStatement({
+                    body: toplevel,
+                });
+                toplevel = new UglifyJS.AST_Toplevel({
+                    body: [ toplevel ],
+                });
+            }
+            toplevel.figure_out_scope({});
+        }
         print(JSON.stringify(result.ast, function(key, value) {
             if (value) switch (key) {
               case "thedef":

lib/ast.js

@@ -203,6 +203,10 @@ var AST_Directive = DEFNODE("Directive", "value quote", {
     },
 }, AST_Statement);
 
+var AST_EmptyStatement = DEFNODE("EmptyStatement", null, {
+    $documentation: "The empty statement (empty block or simply a semicolon)"
+}, AST_Statement);
+
 function must_be_expression(node, prop) {
     if (!(node[prop] instanceof AST_Node)) throw new Error(prop + " must be AST_Node");
     if (node[prop] instanceof AST_Statement && !(node[prop] instanceof AST_Function)) {
@@ -226,6 +230,34 @@ var AST_SimpleStatement = DEFNODE("SimpleStatement", "body", {
     },
 }, AST_Statement);
 
+var AST_BlockScope = DEFNODE("BlockScope", "enclosed functions make_def parent_scope variables", {
+    $documentation: "Base class for all statements introducing a lexical scope",
+    $propdoc: {
+        enclosed: "[SymbolDef*/S] a list of all symbol definitions that are accessed from this scope or any subscopes",
+        functions: "[Object/S] like `variables`, but only lists function declarations",
+        parent_scope: "[AST_Scope?/S] link to the parent scope",
+        variables: "[Object/S] a map of name -> SymbolDef for all variables/functions defined in this scope",
+    },
+    clone: function(deep) {
+        var node = this._clone(deep);
+        if (this.enclosed) node.enclosed = this.enclosed.slice();
+        if (this.functions) node.functions = this.functions.clone();
+        if (this.variables) node.variables = this.variables.clone();
+        return node;
+    },
+    pinned: function() {
+        return this.resolve().pinned();
+    },
+    resolve: function() {
+        return this.parent_scope.resolve();
+    },
+    _validate: function() {
+        if (this.parent_scope == null) return;
+        if (!(this.parent_scope instanceof AST_BlockScope)) throw new Error("parent_scope must be AST_BlockScope");
+        if (!(this.resolve() instanceof AST_Scope)) throw new Error("must be contained within AST_Scope");
+    },
+}, AST_Statement);
+
 function walk_body(node, visitor) {
     node.body.forEach(function(node) {
         node.walk(visitor);
@@ -249,16 +281,12 @@ var AST_Block = DEFNODE("Block", "body", {
             if (node instanceof AST_Function) throw new Error("body cannot contain AST_Function");
         });
     },
-}, AST_Statement);
+}, AST_BlockScope);
 
 var AST_BlockStatement = DEFNODE("BlockStatement", null, {
     $documentation: "A block statement",
 }, AST_Block);
 
-var AST_EmptyStatement = DEFNODE("EmptyStatement", null, {
-    $documentation: "The empty statement (empty block or simply a semicolon)"
-}, AST_Statement);
-
 var AST_StatementWithBody = DEFNODE("StatementWithBody", "body", {
     $documentation: "Base class for all statements that contain one nested body: `For`, `ForIn`, `Do`, `While`, `With`",
     $propdoc: {
@@ -268,7 +296,7 @@ var AST_StatementWithBody = DEFNODE("StatementWithBody", "body", {
         if (!(this.body instanceof AST_Statement)) throw new Error("body must be AST_Statement");
         if (this.body instanceof AST_Function) throw new Error("body cannot be AST_Function");
     },
-}, AST_Statement);
+}, AST_BlockScope);
 
 var AST_LabeledStatement = DEFNODE("LabeledStatement", "label", {
     $documentation: "Statement with a label",
@@ -412,32 +440,16 @@ var AST_With = DEFNODE("With", "expression", {
 
 /* -----[ scope and functions ]----- */
 
-var AST_Scope = DEFNODE("Scope", "cname enclosed uses_eval uses_with parent_scope functions variables make_def", {
+var AST_Scope = DEFNODE("Scope", "uses_eval uses_with", {
     $documentation: "Base class for all statements introducing a lexical scope",
     $propdoc: {
-        cname: "[integer/S] current index for mangling variables (used internally by the mangler)",
-        enclosed: "[SymbolDef*/S] a list of all symbol definitions that are accessed from this scope or any subscopes",
         uses_eval: "[boolean/S] tells whether this scope contains a direct call to the global `eval`",
         uses_with: "[boolean/S] tells whether this scope uses the `with` statement",
-        parent_scope: "[AST_Scope?/S] link to the parent scope",
-        functions: "[Object/S] like `variables`, but only lists function declarations",
-        variables: "[Object/S] a map of name -> SymbolDef for all variables/functions defined in this scope",
-    },
-    clone: function(deep) {
-        var node = this._clone(deep);
-        if (this.variables) node.variables = this.variables.clone();
-        if (this.functions) node.functions = this.functions.clone();
-        if (this.enclosed) node.enclosed = this.enclosed.slice();
-        return node;
     },
     pinned: function() {
         return this.uses_eval || this.uses_with;
     },
-    _validate: function() {
-        if (this.parent_scope != null) {
-            if (!(this.parent_scope instanceof AST_Scope)) throw new Error("parent_scope must be AST_Scope");
-        }
-    },
+    resolve: return_this,
 }, AST_Block);
 
 var AST_Toplevel = DEFNODE("Toplevel", "globals", {
@@ -691,17 +703,19 @@ var AST_Try = DEFNODE("Try", "bcatch bfinally", {
 var AST_Catch = DEFNODE("Catch", "argname", {
     $documentation: "A `catch` node; only makes sense as part of a `try` statement",
     $propdoc: {
-        argname: "[AST_SymbolCatch] symbol for the exception"
+        argname: "[AST_SymbolCatch?] symbol for the exception, or null if not present",
     },
     walk: function(visitor) {
         var node = this;
         visitor.visit(node, function() {
-            node.argname.walk(visitor);
+            if (node.argname) node.argname.walk(visitor);
             walk_body(node, visitor);
         });
     },
     _validate: function() {
-        if (!(this.argname instanceof AST_SymbolCatch)) throw new Error("argname must be AST_SymbolCatch");
+        if (this.argname != null) {
+            if (!(this.argname instanceof AST_SymbolCatch)) throw new Error("argname must be AST_SymbolCatch");
+        }
     },
 }, AST_Block);
 
@@ -723,14 +737,30 @@ var AST_Definitions = DEFNODE("Definitions", "definitions", {
                 defn.walk(visitor);
             });
         });
-    }
+    },
+    _validate: function() {
+        if (this.definitions.length < 1) throw new Error("must have at least one definition");
+    },
 }, AST_Statement);
 
+var AST_Const = DEFNODE("Const", null, {
+    $documentation: "A `const` statement",
+    _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");
+        });
+    },
+}, AST_Definitions);
+
 var AST_Var = DEFNODE("Var", null, {
     $documentation: "A `var` statement",
     _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");
+            if (node.value != null) must_be_expression(node, "value");
         });
     },
 }, AST_Definitions);
@@ -748,10 +778,6 @@ var AST_VarDef = DEFNODE("VarDef", "name value", {
             if (node.value) node.value.walk(visitor);
         });
     },
-    _validate: function() {
-        if (!(this.name instanceof AST_SymbolVar)) throw new Error("name must be AST_SymbolVar");
-        if (this.value != null) must_be_expression(this, "value");
-    },
 });
 
 /* -----[ OTHER ]----- */
@@ -1017,12 +1043,12 @@ var AST_ObjectGetter = DEFNODE("ObjectGetter", null, {
 }, AST_ObjectProperty);
 
 var AST_Symbol = DEFNODE("Symbol", "scope name thedef", {
+    $documentation: "Base class for all symbols",
     $propdoc: {
         name: "[string] name of this symbol",
         scope: "[AST_Scope/S] the current scope (not necessarily the definition scope)",
         thedef: "[SymbolDef/S] the definition of this symbol"
     },
-    $documentation: "Base class for all symbols",
     _validate: function() {
         if (typeof this.name != "string") throw new Error("name must be string");
     },
@@ -1036,6 +1062,10 @@ var AST_SymbolDeclaration = DEFNODE("SymbolDeclaration", "init", {
     $documentation: "A declaration symbol (symbol in var, function name or argument, symbol in catch)",
 }, AST_Symbol);
 
+var AST_SymbolConst = DEFNODE("SymbolConst", null, {
+    $documentation: "Symbol defining a constant",
+}, AST_SymbolDeclaration);
+
 var AST_SymbolVar = DEFNODE("SymbolVar", null, {
     $documentation: "Symbol defining a variable",
 }, AST_SymbolDeclaration);

lib/output.js

@@ -835,10 +835,6 @@ function OutputStream(options) {
         use_asm = was_asm;
     }
 
-    AST_StatementWithBody.DEFMETHOD("_do_print_body", function(output) {
-        force_statement(this.body, output);
-    });
-
     DEFPRINT(AST_Statement, function(output) {
         this.body.print(output);
         output.semicolon();
@@ -897,7 +893,7 @@ function OutputStream(options) {
             self.condition.print(output);
         });
         output.space();
-        self._do_print_body(output);
+        force_statement(self.body, output);
     });
     DEFPRINT(AST_For, function(output) {
         var self = this;
@@ -927,7 +923,7 @@ function OutputStream(options) {
             }
         });
         output.space();
-        self._do_print_body(output);
+        force_statement(self.body, output);
     });
     DEFPRINT(AST_ForIn, function(output) {
         var self = this;
@@ -941,7 +937,7 @@ function OutputStream(options) {
             self.object.print(output);
         });
         output.space();
-        self._do_print_body(output);
+        force_statement(self.body, output);
     });
     DEFPRINT(AST_With, function(output) {
         var self = this;
@@ -951,7 +947,7 @@ function OutputStream(options) {
             self.expression.print(output);
         });
         output.space();
-        self._do_print_body(output);
+        force_statement(self.body, output);
     });
 
     /* -----[ functions ]----- */
@@ -994,7 +990,7 @@ function OutputStream(options) {
     /* -----[ if ]----- */
     function make_then(self, output) {
         var b = self.body;
-        if (output.option("braces")
+        if (output.option("braces") && !(b instanceof AST_Const)
             || output.option("ie8") && b instanceof AST_Do)
             return make_block(b, output);
         // The squeezer replaces "block"-s that contain only a single
@@ -1036,7 +1032,7 @@ function OutputStream(options) {
             else
                 force_statement(self.alternative, output);
         } else {
-            self._do_print_body(output);
+            force_statement(self.body, output);
         }
     });
 
@@ -1099,10 +1095,12 @@ function OutputStream(options) {
     DEFPRINT(AST_Catch, function(output) {
         var self = this;
         output.print("catch");
-        output.space();
-        output.with_parens(function() {
-            self.argname.print(output);
-        });
+        if (self.argname) {
+            output.space();
+            output.with_parens(function() {
+                self.argname.print(output);
+            });
+        }
         output.space();
         print_braced(self, output);
     });
@@ -1112,17 +1110,21 @@ function OutputStream(options) {
         print_braced(this, output);
     });
 
-    DEFPRINT(AST_Var, function(output) {
-        var self = this;
-        output.print("var");
-        output.space();
-        self.definitions.forEach(function(def, i) {
-            if (i) output.comma();
-            def.print(output);
-        });
-        var p = output.parent();
-        if (p && p.init !== self || !(p instanceof AST_For || p instanceof AST_ForIn)) output.semicolon();
-    });
+    function print_definitinos(type) {
+        return function(output) {
+            var self = this;
+            output.print(type);
+            output.space();
+            self.definitions.forEach(function(def, i) {
+                if (i) output.comma();
+                def.print(output);
+            });
+            var p = output.parent();
+            if (p && p.init !== self || !(p instanceof AST_For || p instanceof AST_ForIn)) output.semicolon();
+        };
+    }
+    DEFPRINT(AST_Const, print_definitinos("const"));
+    DEFPRINT(AST_Var, print_definitinos("var"));
 
     function parenthesize_for_noin(node, output, noin) {
         var parens = false;
@@ -1379,13 +1381,12 @@ function OutputStream(options) {
     });
 
     function force_statement(stat, output) {
-        if (output.option("braces")) {
+        if (output.option("braces") && !(stat instanceof AST_Const)) {
             make_block(stat, output);
+        } else if (!stat || stat instanceof AST_EmptyStatement) {
+            output.force_semicolon();
         } else {
-            if (!stat || stat instanceof AST_EmptyStatement)
-                output.force_semicolon();
-            else
-                stat.print(output);
+            stat.print(output);
         }
     }
 

lib/parse.js

@@ -60,8 +60,9 @@ KEYWORDS_ATOM = makePredicate(KEYWORDS_ATOM);
 
 var OPERATOR_CHARS = makePredicate(characters("+-*&%=<>!?|~^"));
 
-var RE_HEX_NUMBER = /^0x[0-9a-f]+$/i;
-var RE_OCT_NUMBER = /^0[0-7]+$/;
+var RE_BIN_NUMBER = /^0b([01]+)$/i;
+var RE_HEX_NUMBER = /^0x([0-9a-f]+)$/i;
+var RE_OCT_NUMBER = /^0o?([0-7]+)$/i;
 
 var OPERATORS = makePredicate([
     "in",
@@ -147,10 +148,6 @@ function is_digit(code) {
     return code >= 48 && code <= 57;
 }
 
-function is_alphanumeric_char(code) {
-    return is_digit(code) || is_letter(code);
-}
-
 function is_unicode_digit(code) {
     return UNICODE.digit.test(String.fromCharCode(code));
 }
@@ -184,14 +181,12 @@ function is_identifier_string(str) {
 }
 
 function parse_js_number(num) {
-    if (RE_HEX_NUMBER.test(num)) {
-        return parseInt(num.substr(2), 16);
-    } else if (RE_OCT_NUMBER.test(num)) {
-        return parseInt(num.substr(1), 8);
-    } else {
-        var val = parseFloat(num);
-        if (val == num) return val;
-    }
+    var match;
+    if (match = RE_BIN_NUMBER.exec(num)) return parseInt(match[1], 2);
+    if (match = RE_HEX_NUMBER.exec(num)) return parseInt(match[1], 16);
+    if (match = RE_OCT_NUMBER.exec(num)) return parseInt(match[1], 8);
+    var val = parseFloat(num);
+    if (val == num) return val;
 }
 
 function JS_Parse_Error(message, filename, line, col, pos) {
@@ -347,11 +342,13 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
               case (after_e = false, 46): // .
                 return (!has_dot && !has_x && !has_e) ? (has_dot = true) : false;
             }
-            return is_alphanumeric_char(code);
+            return is_digit(code) || is_letter(code) || ch == "_";
         });
         if (prefix) num = prefix + num;
-        if (RE_OCT_NUMBER.test(num) && next_token.has_directive("use strict")) {
-            parse_error("Legacy octal literals are not allowed in strict mode");
+        if (/^0[0-7_]+$/.test(num)) {
+            if (next_token.has_directive("use strict")) parse_error("Legacy octal literals are not allowed in strict mode");
+        } else {
+            num = num.replace(has_x ? /([1-9a-f]|.0)_(?=[0-9a-f])/gi : /([1-9]|.0)_(?=[0-9])/gi, "$1");
         }
         var valid = parse_js_number(num);
         if (!isNaN(valid)) return token("num", valid);
@@ -835,6 +832,12 @@ function parse($TEXT, options) {
                 next();
                 return break_cont(AST_Break);
 
+              case "const":
+                next();
+                var node = const_();
+                semicolon();
+                return node;
+
               case "continue":
                 next();
                 return break_cont(AST_Continue);
@@ -991,7 +994,9 @@ function parse($TEXT, options) {
         expect("(");
         var init = null;
         if (!is("punc", ";")) {
-            init = is("keyword", "var")
+            init = is("keyword", "const")
+                ? (next(), const_(true))
+                : is("keyword", "var")
                 ? (next(), var_(true))
                 : expression(true, true);
             if (is("operator", "in")) {
@@ -1133,9 +1138,12 @@ function parse($TEXT, options) {
         if (is("keyword", "catch")) {
             var start = S.token;
             next();
-            expect("(");
-            var name = as_symbol(AST_SymbolCatch);
-            expect(")");
+            var name = null;
+            if (is("punc", "(")) {
+                next();
+                name = as_symbol(AST_SymbolCatch);
+                expect(")");
+            }
             bcatch = new AST_Catch({
                 start   : start,
                 argname : name,
@@ -1161,13 +1169,22 @@ function parse($TEXT, options) {
         });
     }
 
-    function vardefs(no_in) {
+    function vardefs(type, no_in, must_init) {
         var a = [];
         for (;;) {
+            var start = S.token;
+            var name = as_symbol(type);
+            var value = null;
+            if (is("operator", "=")) {
+                next();
+                value = expression(false, no_in);
+            } else if (must_init) {
+                croak("Missing initializer in declaration");
+            }
             a.push(new AST_VarDef({
-                start : S.token,
-                name  : as_symbol(AST_SymbolVar),
-                value : is("operator", "=") ? (next(), expression(false, no_in)) : null,
+                start : start,
+                name  : name,
+                value : value,
                 end   : prev()
             }));
             if (!is("punc", ","))
@@ -1177,10 +1194,18 @@ function parse($TEXT, options) {
         return a;
     }
 
+    var const_ = function(no_in) {
+        return new AST_Const({
+            start       : prev(),
+            definitions : vardefs(AST_SymbolConst, no_in, true),
+            end         : prev()
+        });
+    };
+
     var var_ = function(no_in) {
         return new AST_Var({
             start       : prev(),
-            definitions : vardefs(no_in),
+            definitions : vardefs(AST_SymbolVar, no_in),
             end         : prev()
         });
     };

lib/scope.js

@@ -59,21 +59,17 @@ function SymbolDef(id, scope, orig, init) {
 }
 
 SymbolDef.prototype = {
-    unmangleable: function(options) {
-        return this.global && !options.toplevel
-            || this.undeclared
-            || !options.eval && this.scope.pinned()
-            || options.keep_fnames
-                && (this.orig[0] instanceof AST_SymbolLambda
-                    || this.orig[0] instanceof AST_SymbolDefun);
+    forEach: function(fn) {
+        this.orig.forEach(fn);
+        this.references.forEach(fn);
     },
     mangle: function(options) {
         var cache = options.cache && options.cache.props;
         if (this.global && cache && cache.has(this.name)) {
             this.mangled_name = cache.get(this.name);
         } else if (!this.mangled_name && !this.unmangleable(options)) {
-            var def;
-            if (def = this.redefined()) {
+            var def = this.redefined();
+            if (def) {
                 this.mangled_name = def.mangled_name || def.name;
             } else {
                 this.mangled_name = next_mangled_name(this.scope, options, this);
@@ -84,8 +80,24 @@ SymbolDef.prototype = {
         }
     },
     redefined: function() {
-        return this.defun && this.defun.variables.get(this.name);
-    }
+        var scope = this.defun;
+        if (!scope) return;
+        var name = this.name;
+        var def = scope.variables.get(name)
+            || scope instanceof AST_Toplevel && scope.globals.get(name)
+            || this.orig[0] instanceof AST_SymbolConst && find_if(function(def) {
+                return def.name == name;
+            }, scope.enclosed);
+        if (def && def !== this) return def.redefined() || def;
+    },
+    unmangleable: function(options) {
+        return this.global && !options.toplevel
+            || this.undeclared
+            || !options.eval && this.scope.pinned()
+            || options.keep_fnames
+                && (this.orig[0] instanceof AST_SymbolLambda
+                    || this.orig[0] instanceof AST_SymbolDefun);
+    },
 };
 
 AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
@@ -100,27 +112,42 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
     var next_def_id = 0;
     var scope = self.parent_scope = null;
     var tw = new TreeWalker(function(node, descend) {
-        if (node instanceof AST_Catch) {
-            var save_scope = scope;
-            scope = new AST_Scope(node);
-            scope.init_scope_vars(save_scope);
-            descend();
-            scope = save_scope;
+        if (node instanceof AST_Defun) {
+            node.name.walk(tw);
+            walk_scope(function() {
+                node.argnames.forEach(function(argname) {
+                    argname.walk(tw);
+                });
+                walk_body(node, tw);
+            });
             return true;
         }
-        if (node instanceof AST_Scope) {
-            node.init_scope_vars(scope);
-            var save_scope = scope;
-            var save_defun = defun;
-            defun = scope = node;
+        if (node instanceof AST_SwitchBranch) {
+            node.init_vars(scope);
             descend();
-            scope = save_scope;
-            defun = save_defun;
+            return true;
+        }
+        if (node instanceof AST_Try) {
+            walk_scope(function() {
+                walk_body(node, tw);
+            });
+            if (node.bcatch) node.bcatch.walk(tw);
+            if (node.bfinally) node.bfinally.walk(tw);
             return true;
         }
         if (node instanceof AST_With) {
-            for (var s = scope; s; s = s.parent_scope) s.uses_with = true;
-            return;
+            var s = scope;
+            do {
+                s = s.resolve();
+                if (s.uses_with) break;
+                s.uses_with = true;
+            } while (s = s.parent_scope);
+            walk_scope(descend);
+            return true;
+        }
+        if (node instanceof AST_BlockScope) {
+            walk_scope(descend);
+            return true;
         }
         if (node instanceof AST_Symbol) {
             node.scope = scope;
@@ -129,25 +156,43 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             node.thedef = node;
             node.references = [];
         }
-        if (node instanceof AST_SymbolDefun) {
-            // This should be defined in the parent scope, as we encounter the
-            // AST_Defun node before getting to its AST_Symbol.
-            (node.scope = defun.parent_scope.resolve()).def_function(node, defun);
+        if (node instanceof AST_SymbolCatch) {
+            scope.def_variable(node).defun = defun;
+        } else if (node instanceof AST_SymbolConst) {
+            scope.def_variable(node).defun = defun;
+        } else if (node instanceof AST_SymbolDefun) {
+            defun.def_function(node, tw.parent());
+            entangle(defun, scope);
+        } else if (node instanceof AST_SymbolFunarg) {
+            defun.def_variable(node);
+            entangle(defun, scope);
         } else if (node instanceof AST_SymbolLambda) {
             var def = defun.def_function(node, node.name == "arguments" ? undefined : defun);
             if (options.ie8) def.defun = defun.parent_scope.resolve();
         } else if (node instanceof AST_SymbolVar) {
-            defun.def_variable(node, node.TYPE == "SymbolVar" ? null : undefined);
-            if (defun !== scope) {
-                node.mark_enclosed(options);
-                var def = scope.find_variable(node);
-                if (node.thedef !== def) {
-                    node.thedef = def;
-                }
-                node.reference(options);
-            }
-        } else if (node instanceof AST_SymbolCatch) {
-            scope.def_variable(node).defun = defun;
+            defun.def_variable(node, null);
+            entangle(defun, scope);
+        }
+
+        function walk_scope(descend) {
+            node.init_vars(scope);
+            var save_defun = defun;
+            var save_scope = scope;
+            if (node instanceof AST_Scope) defun = node;
+            scope = node;
+            descend();
+            scope = save_scope;
+            defun = save_defun;
+        }
+
+        function entangle(defun, scope) {
+            if (defun === scope) return;
+            node.mark_enclosed(options);
+            var def = scope.find_variable(node);
+            if (node.thedef === def) return;
+            node.thedef = def;
+            def.orig.push(node);
+            node.mark_enclosed(options);
         }
     });
     self.make_def = function(orig, init) {
@@ -167,15 +212,18 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             var sym = node.scope.find_variable(name);
             if (!sym) {
                 sym = self.def_global(node);
-            } else if (sym.scope instanceof AST_Lambda && name == "arguments") {
+            } else if (name == "arguments" && sym.scope instanceof AST_Lambda) {
                 sym.scope.uses_arguments = true;
             }
             if (name == "eval") {
                 var parent = tw.parent();
                 if (parent.TYPE == "Call" && parent.expression === node) {
-                    for (var s = node.scope; s && !s.uses_eval; s = s.parent_scope) {
+                    var s = node.scope;
+                    do {
+                        s = s.resolve();
+                        if (s.uses_eval) break;
                         s.uses_eval = true;
-                    }
+                    } while (s = s.parent_scope);
                 } else if (sym.undeclared) {
                     self.uses_eval = true;
                 }
@@ -184,7 +232,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             node.reference(options);
             return true;
         }
-        // ensure mangling works if catch reuses a scope variable
+        // ensure mangling works if `catch` reuses a scope variable
         if (node instanceof AST_SymbolCatch) {
             var def = node.definition().redefined();
             if (def) for (var s = node.scope; s; s = s.parent_scope) {
@@ -193,6 +241,12 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             }
             return true;
         }
+        // ensure compression works if `const` reuses a scope variable
+        if (node instanceof AST_SymbolConst) {
+            var redef = node.definition().redefined();
+            if (redef) redef.const_redefs = true;
+            return true;
+        }
     });
     self.walk(tw);
 
@@ -223,8 +277,8 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
         var old_def = node.thedef;
         var new_def = scope.find_variable(name);
         if (new_def) {
-            var redef;
-            while (redef = new_def.redefined()) new_def = redef;
+            var redef = new_def.redefined();
+            if (redef) new_def = redef;
         } else {
             new_def = self.globals.get(name);
         }
@@ -234,7 +288,8 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options) {
             new_def = scope.def_variable(node);
         }
         old_def.defun = new_def.scope;
-        old_def.orig.concat(old_def.references).forEach(function(node) {
+        old_def.forEach(function(node) {
+            node.redef = true;
             node.thedef = new_def;
             node.reference(options);
         });
@@ -256,22 +311,27 @@ AST_Toplevel.DEFMETHOD("def_global", function(node) {
     }
 });
 
-function init_scope_vars(scope, parent) {
-    scope.cname = -1;                               // the current index for mangling functions/variables
+function init_block_vars(scope, parent) {
     scope.enclosed = [];                            // variables from this or outer scope(s) that are referenced from this or inner scopes
-    scope.uses_eval = false;                        // will be set to true if this or nested scope uses the global `eval`
-    scope.uses_with = false;                        // will be set to true if this or some nested scope uses the `with` statement
     scope.parent_scope = parent;                    // the parent scope (null if this is the top level)
     scope.functions = new Dictionary();             // map name to AST_SymbolDefun (functions defined in this scope)
     scope.variables = new Dictionary();             // map name to AST_SymbolVar (variables defined in this scope; includes functions)
     if (parent) scope.make_def = parent.make_def;   // top-level tracking of SymbolDef instances
 }
 
-AST_Scope.DEFMETHOD("init_scope_vars", function(parent_scope) {
+function init_scope_vars(scope, parent) {
+    init_block_vars(scope, parent);
+    scope.uses_eval = false;                        // will be set to true if this or nested scope uses the global `eval`
+    scope.uses_with = false;                        // will be set to true if this or some nested scope uses the `with` statement
+}
+
+AST_BlockScope.DEFMETHOD("init_vars", function(parent_scope) {
+    init_block_vars(this, parent_scope);
+});
+AST_Scope.DEFMETHOD("init_vars", function(parent_scope) {
     init_scope_vars(this, parent_scope);
 });
-
-AST_Lambda.DEFMETHOD("init_scope_vars", function(parent_scope) {
+AST_Lambda.DEFMETHOD("init_vars", function(parent_scope) {
     init_scope_vars(this, parent_scope);
     this.uses_arguments = false;
     this.def_variable(new AST_SymbolFunarg({
@@ -300,20 +360,20 @@ AST_Symbol.DEFMETHOD("reference", function(options) {
     this.mark_enclosed(options);
 });
 
-AST_Scope.DEFMETHOD("find_variable", function(name) {
+AST_BlockScope.DEFMETHOD("find_variable", function(name) {
     if (name instanceof AST_Symbol) name = name.name;
     return this.variables.get(name)
         || (this.parent_scope && this.parent_scope.find_variable(name));
 });
 
-AST_Scope.DEFMETHOD("def_function", function(symbol, init) {
+AST_BlockScope.DEFMETHOD("def_function", function(symbol, init) {
     var def = this.def_variable(symbol, init);
     if (!def.init || def.init instanceof AST_Defun) def.init = init;
     this.functions.set(symbol.name, def);
     return def;
 });
 
-AST_Scope.DEFMETHOD("def_variable", function(symbol, init) {
+AST_BlockScope.DEFMETHOD("def_variable", function(symbol, init) {
     var def = this.variables.get(symbol.name);
     if (def) {
         def.orig.push(symbol);
@@ -326,17 +386,12 @@ AST_Scope.DEFMETHOD("def_variable", function(symbol, init) {
     return symbol.thedef = def;
 });
 
-AST_Lambda.DEFMETHOD("resolve", return_this);
-AST_Scope.DEFMETHOD("resolve", function() {
-    return this.parent_scope.resolve();
-});
-AST_Toplevel.DEFMETHOD("resolve", return_this);
-
 function names_in_use(scope, options) {
     var names = scope.names_in_use;
     if (!names) {
-        scope.names_in_use = names = Object.create(null);
+        scope.cname = -1;
         scope.cname_holes = [];
+        scope.names_in_use = names = Object.create(null);
         var cache = options.cache && options.cache.props;
         scope.enclosed.forEach(function(def) {
             if (def.unmangleable(options)) names[def.name] = true;
@@ -353,7 +408,7 @@ function next_mangled_name(scope, options, def) {
     var holes = scope.cname_holes;
     var names = Object.create(null);
     var scopes = [ scope ];
-    def.references.forEach(function(sym) {
+    def.forEach(function(sym) {
         var scope = sym.scope;
         do {
             if (scopes.indexOf(scope) < 0) {
@@ -434,7 +489,11 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
             lname = save_nesting;
             return true;
         }
-        if (node instanceof AST_Scope) {
+        if (node instanceof AST_BlockScope) {
+            var to_mangle = [];
+            node.variables.each(function(def) {
+                if (!defer_redef(def)) to_mangle.push(def);
+            });
             descend();
             if (options.cache && node instanceof AST_Toplevel) {
                 node.globals.each(mangle);
@@ -444,9 +503,7 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
                 sym.scope = node;
                 sym.reference(options);
             }
-            node.variables.each(function(def) {
-                if (!defer_redef(def)) mangle(def);
-            });
+            to_mangle.forEach(mangle);
             return true;
         }
         if (node instanceof AST_Label) {
@@ -457,13 +514,6 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
             node.mangled_name = name;
             return true;
         }
-        if (!options.ie8 && node instanceof AST_Catch) {
-            var def = node.argname.definition();
-            var redef = defer_redef(def, node.argname);
-            descend();
-            if (!redef) mangle(def);
-            return true;
-        }
     });
     this.walk(tw);
     redefined.forEach(mangle);
@@ -478,7 +528,8 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
         if (!redef) return false;
         redefined.push(def);
         def.references.forEach(reference);
-        if (node) reference(node);
+        var node = def.orig[0];
+        if (node instanceof AST_SymbolCatch || node instanceof AST_SymbolConst) reference(node);
         return true;
 
         function reference(sym) {
@@ -495,8 +546,7 @@ AST_Toplevel.DEFMETHOD("find_colliding_names", function(options) {
     options.reserved.forEach(to_avoid);
     this.globals.each(add_def);
     this.walk(new TreeWalker(function(node) {
-        if (node instanceof AST_Scope) node.variables.each(add_def);
-        if (node instanceof AST_SymbolCatch) add_def(node.definition());
+        if (node instanceof AST_BlockScope) node.variables.each(add_def);
     }));
     return avoid;
 
@@ -520,8 +570,7 @@ AST_Toplevel.DEFMETHOD("expand_names", function(options) {
     var cname = 0;
     this.globals.each(rename);
     this.walk(new TreeWalker(function(node) {
-        if (node instanceof AST_Scope) node.variables.each(rename);
-        if (node instanceof AST_SymbolCatch) rename(node.definition());
+        if (node instanceof AST_BlockScope) node.variables.each(rename);
     }));
 
     function next_name() {
@@ -539,7 +588,7 @@ AST_Toplevel.DEFMETHOD("expand_names", function(options) {
         var redef = def.redefined();
         var name = redef ? redef.rename || redef.name : next_name();
         def.rename = name;
-        def.orig.concat(def.references).forEach(function(sym) {
+        def.forEach(function(sym) {
             if (sym.definition() === def) sym.name = name;
         });
     }

lib/transform.js

@@ -116,7 +116,7 @@ TreeTransformer.prototype = new TreeWalker;
         if (self.bfinally) self.bfinally = self.bfinally.transform(tw);
     });
     DEF(AST_Catch, function(self, tw) {
-        self.argname = self.argname.transform(tw);
+        if (self.argname) self.argname = self.argname.transform(tw);
         self.body = do_list(self.body, tw);
     });
     DEF(AST_Definitions, function(self, tw) {

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": "3.11.0",
+  "version": "3.11.3",
   "engines": {
     "node": ">=0.8.0"
   },

test/compress/arguments.js

@@ -783,3 +783,27 @@ issue_3420_7: {
     }
     expect_stdout: "true"
 }
+
+issue_4200: {
+    options = {
+        arguments: true,
+        keep_fargs: false,
+    }
+    input: {
+        var o = {
+            get p() {
+                return arguments[0];
+            },
+        };
+        console.log(o.p);
+    }
+    expect: {
+        var o = {
+            get p() {
+                return arguments[0];
+            },
+        };
+        console.log(o.p);
+    }
+    expect_stdout: "undefined"
+}

test/compress/asm.js

@@ -76,9 +76,8 @@ asm_mixed: {
                 start = start | 0;
                 end = end | 0;
                 var sum = 0.0, p = 0, q = 0;
-                for (p = start << 3, q = end << 3; (p | 0) < (q | 0); p = p + 8 | 0) {
+                for (p = start << 3, q = end << 3; (p | 0) < (q | 0); p = p + 8 | 0)
                     sum = sum + +log(values[p >> 3]);
-                }
                 return +sum;
             }
             function geometricMean(start, end) {
@@ -91,7 +90,8 @@ asm_mixed: {
         function no_asm_GeometricMean(stdlib, foreign, buffer) {
             function logSum(start, end) {
                 start |= 0, end |= 0;
-                for (var sum = 0, p = 0, q = 0, p = start << 3, q = end << 3; (0 | p) < (0 | q); p = p + 8 | 0) sum += +log(values[p >> 3]);
+                for (var sum = 0, p = 0, q = 0, p = start << 3, q = end << 3; (0 | p) < (0 | q); p = p + 8 | 0)
+                    sum += +log(values[p >> 3]);
                 return +sum;
             }
             function geometricMean(start, end) {

test/compress/collapse_vars.js

@@ -346,9 +346,8 @@ collapse_vars_if: {
             return "x" != "Bar" + x / 4 ? g9 : g5;
         }
         function f3(x) {
-            if (x) {
+            if (x)
                 return 1;
-            }
             return 2;
         }
     }
@@ -4192,9 +4191,8 @@ issue_2436_11: {
             if (isCollection(arg1)) {
                 var size = arg1, max = arg2, min = 0, res = _randomDataForMatrix(size.valueOf(), min, max, _randomInt);
                 return size && true === size.isMatrix ? matrix(res) : res;
-            } else {
+            } else
                 return _randomInt(min = arg1, max = arg2);
-            }
         }
     }
 }
@@ -4310,9 +4308,8 @@ issue_2497: {
         function sample() {
             if (true)
                 for (var i = 0; i < 1; ++i)
-                    for (var k = 0; k < 1; ++k) {
+                    for (var k = 0; k < 1; ++k)
                         value = (value = 1) ? value + 1 : 0;
-                    }
             else
                 for (i = 0; i < 1; ++i)
                     for (k = 0; k < 1; ++k)

test/compress/conditionals.js

@@ -55,14 +55,15 @@ ifs_3_should_warn: {
     }
     input: {
         var x, y;
-        if (x && !(x + "1") && y) { // 1
+        // 1
+        if (x && !(x + "1") && y) {
             var qq;
             foo();
         } else {
             bar();
         }
-
-        if (x || !!(x + "1") || y) { // 2
+        // 2
+        if (x || !!(x + "1") || y) {
             foo();
         } else {
             var jj;
@@ -71,9 +72,27 @@ ifs_3_should_warn: {
     }
     expect: {
         var x, y;
-        var qq; bar();          // 1
-        var jj; foo();          // 2
+        // 1
+        var qq; bar();
+        // 2
+        foo(); var jj;
     }
+    expect_warnings: [
+        "WARN: + in boolean context always true [test/compress/conditionals.js:3,18]",
+        "WARN: Boolean && always false [test/compress/conditionals.js:3,12]",
+        "WARN: Condition left of && always false [test/compress/conditionals.js:3,12]",
+        "WARN: Condition always false [test/compress/conditionals.js:3,12]",
+        "WARN: Dropping 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]",
+    ]
 }
 
 ifs_4: {
@@ -1159,7 +1178,7 @@ issue_1645_2: {
     expect_stdout: true
 }
 
-condition_symbol_matches_consequent: {
+condition_matches_consequent: {
     options = {
         conditionals: true,
     }
@@ -1188,6 +1207,35 @@ condition_symbol_matches_consequent: {
     expect_stdout: "3 7 true 4"
 }
 
+condition_matches_alternative: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        function foo(x, y) {
+            return x.p ? y[0] : x.p;
+        }
+        function bar() {
+            return g ? h : g;
+        }
+        var g = 4;
+        var h = 5;
+        console.log(foo({ p: 3 }, [ null ]), foo({ p: 0 }, [ 7 ]), foo({ p: true } , [ false ]), bar());
+    }
+    expect: {
+        function foo(x, y) {
+            return x.p && y[0];
+        }
+        function bar() {
+            return g && h;
+        }
+        var g = 4;
+        var h = 5;
+        console.log(foo({ p: 3 }, [ null ]), foo({ p: 0 }, [ 7 ]), foo({ p: true } , [ false ]), bar());
+    }
+    expect_stdout: "null 0 false 5"
+}
+
 delete_conditional_1: {
     options = {
         booleans: true,

test/compress/dead-code.js

@@ -59,6 +59,11 @@ dead_code_2_should_warn: {
         f();
     }
     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"
 }
 
@@ -89,11 +94,23 @@ dead_code_constant_boolean_should_warn_more: {
         function bar() {}
         // nothing for the while
         // as for the for, it should keep:
-        var moo;
         var x = 10, y;
+        var moo;
         bar();
     }
     expect_stdout: true
+    expect_warnings: [
+        "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]",
+    ]
     node_version: "<=4"
 }
 

test/compress/drop-unused.js

@@ -2992,3 +2992,96 @@ issue_4146: {
     }
     expect_stdout: "function"
 }
+
+var_catch_redefined: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            throw "PASS";
+        } catch (a) {
+            function f() {
+                return a;
+            }
+            console.log(a);
+        }
+        f();
+    }
+    expect: {
+        var a = "FAIL";
+        try {
+            throw "PASS";
+        } catch (a) {
+            function f() {
+                return a;
+            }
+            console.log(a);
+        }
+        f();
+    }
+    expect_stdout: "PASS"
+}
+
+single_use_catch_redefined: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 1;
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+        }
+        console.log(g());
+    }
+    expect: {
+        var a = 1;
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+        }
+        console.log(g());
+    }
+    expect_stdout: true
+}
+
+issue_4184: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var a = function() {}, b = [ a, 1 && b, a = {} ];
+            try {
+                throw 42;
+            } catch (a) {
+                {
+                    console.log(a);
+                }
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            var b = [ function() {}, 1 && b, {} ];
+            try {
+                throw 42;
+            } catch (a) {
+                console.log(a);
+            }
+        })();
+    }
+    expect_stdout: "42"
+}

test/compress/evaluate.js

@@ -3014,3 +3014,36 @@ issue_4119_4: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4214: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            return function() {
+                try {
+                    return a;
+                } finally {
+                    var b = 0;
+                }
+            }(a++ && this());
+        }
+        var c = f();
+        console.log(c);
+    }
+    expect: {
+        var c = function(a) {
+            return function() {
+                try {
+                    return a;
+                } finally {}
+            }(a++ && this());
+        }();
+        console.log(c);
+    }
+    expect_stdout: "NaN"
+}

test/compress/functions.js

@@ -4808,3 +4808,271 @@ issue_4155: {
         "function",
     ]
 }
+
+issue_4159: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 42, c = function(b) {
+            (b = a) && console.log(a++, b);
+        }(c = a);
+    }
+    expect: {
+        var a = 42;
+        (b = a) && console.log(a++, b);
+        var b;
+    }
+    expect_stdout: "42 42"
+}
+
+direct_inline: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f(a, b) {
+            function g(c) {
+                return c >> 1;
+            }
+            return g(a) + g(b);
+        }
+        console.log(f(13, 31));
+    }
+    expect: {
+        function f(a, b) {
+            return (a >> 1) + (b >> 1);
+        }
+        console.log(f(13, 31));
+    }
+    expect_stdout: "21"
+}
+
+direct_inline_catch_redefined: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 1;
+        function f() {
+            return a;
+        }
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+            console.log(a, f(), g());
+        }
+        console.log(a, f(), g());
+    }
+    expect: {
+        var a = 1;
+        function f() {
+            return a;
+        }
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+            console.log(a, f(), g());
+        }
+        console.log(a, a, g());
+    }
+    expect_stdout: true
+}
+
+issue_4171_1: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a) {
+            try {
+                while (a)
+                    var e = function() {};
+            } catch (e) {
+                return function() {
+                    return e;
+                };
+            }
+        }(!console));
+    }
+    expect: {
+        console.log(function(a) {
+            try {
+                while (a)
+                    var e = function() {};
+            } catch (e) {
+                return function() {
+                    return e;
+                };
+            }
+        }(!console));
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4171_2: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a) {
+            try {
+                while (a);
+            } catch (e) {
+                return function() {
+                    return e;
+                };
+            } finally {
+                var e = function() {};
+            }
+        }(!console));
+    }
+    expect: {
+        console.log(function(a) {
+            try {
+                while (a);
+            } catch (e) {
+                return function() {
+                    return e;
+                };
+            } finally {
+                function e() {}
+            }
+        }(!console));
+    }
+    expect_stdout: "undefined"
+}
+
+catch_defun: {
+    mangle = {
+        toplevel: true,
+    }
+    input: {
+        try {
+            throw 42;
+        } catch (a) {
+            function f() {
+                return typeof a;
+            }
+        }
+        console.log(f());
+    }
+    expect: {
+        try {
+            throw 42;
+        } catch (o) {
+            function t() {
+                return typeof o;
+            }
+        }
+        console.log(t());
+    }
+    expect_stdout: true
+}
+
+catch_no_argname: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        function f() {
+            return a;
+        }
+        try {
+            throw a;
+        } catch {
+            function g() {
+                return a;
+            }
+            console.log(a, f(), g());
+        }
+        console.log(a, f(), g());
+    }
+    expect: {
+        var a = "PASS";
+        try {
+            throw a;
+        } catch {
+            console.log(a, a, a);
+        }
+        console.log(a, a, a);
+    }
+    expect_stdout: [
+        "PASS PASS PASS",
+        "PASS PASS PASS",
+    ]
+    node_version: ">=10"
+}
+
+issue_4186: {
+    options = {
+        conditionals: true,
+        inline: true,
+        reduce_funcs: true,
+        reduce_vars: true,
+        sequences: true,
+        unused: true,
+    }
+    input: {
+        console.log(typeof function() {
+            return function() {
+                function f() {
+                    if (1)
+                        g();
+                    else
+                        (function() {
+                            return f;
+                        });
+                }
+                return f;
+                function g() {
+                    if (1) {
+                        if (0)
+                            h;
+                        else
+                            h();
+                        var key = 0;
+                    }
+                }
+                function h() {
+                    return factory;
+                }
+            };
+        }()());
+    }
+    expect: {
+        console.log(typeof function() {
+            return function f() {
+                1 ? void (1 && (0 ? h : h(), 0)) : function() {
+                    return f;
+                };
+            };
+            function h() {
+                return factory;
+            }
+        }());
+    }
+    expect_stdout: "function"
+}

test/compress/ie8.js

@@ -2714,3 +2714,148 @@ issue_2737: {
     }
     expect_stdout: "function"
 }
+
+single_use_catch_redefined: {
+    options = {
+        ie8: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 1;
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+        }
+        console.log(g());
+    }
+    expect: {
+        var a = 1;
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+        }
+        console.log(g());
+    }
+    expect_stdout: true
+}
+
+single_use_inline_catch_redefined: {
+    options = {
+        ie8: true,
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 1;
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+        }
+        console.log(g());
+    }
+    expect: {
+        var a = 1;
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+        }
+        console.log(g());
+    }
+    expect_stdout: true
+}
+
+direct_inline_catch_redefined: {
+    options = {
+        ie8: true,
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 1;
+        function f() {
+            return a;
+        }
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+            console.log(a, f(), g());
+        }
+        console.log(a, f(), g());
+    }
+    expect: {
+        var a = 1;
+        function f() {
+            return a;
+        }
+        try {
+            throw 2;
+        } catch (a) {
+            function g() {
+                return a;
+            }
+            console.log(a, f(), g());
+        }
+        console.log(a, a, g());
+    }
+    expect_stdout: true
+}
+
+issue_4186: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        ie8: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    mangle = {
+        ie8: true,
+        toplevel: true,
+    }
+    input: {
+        function f() {
+            (function NaN() {
+                var a = 1;
+                while (a--)
+                    try {} finally {
+                        console.log(0/0);
+                        var b;
+                    }
+            })(f);
+        }
+        f();
+        NaN;
+    }
+    expect: {
+        (function() {
+            (function NaN() {
+                var n = 1;
+                while (n--)
+                    console.log(0/0);
+            })();
+        })();
+        NaN;
+    }
+    expect_stdout: "NaN"
+}

test/compress/if_return.js

@@ -663,3 +663,88 @@ nested_if_continue: {
         "even 21",
     ]
 }
+
+nested_if_return: {
+    options = {
+        conditionals: true,
+        if_return: true,
+    }
+    input: {
+        function f() {
+            if (A) {
+                if (B)
+                    return B;
+                if (C)
+                    return D;
+                if (E)
+                    return F;
+                if (G)
+                    return H;
+                if (I) {
+                    if (J)
+                        return K;
+                    return;
+                }
+                if (L) {
+                    if (M)
+                        return;
+                    return N;
+                }
+            }
+        }
+    }
+    expect: {
+        function f() {
+            if (A)
+                return B || (C ? D : E ? F : G ? H : I ? J ? K : void 0 : L && !M ? N : void 0);
+        }
+    }
+}
+
+issue_866_1: {
+    options = {
+        conditionals: true,
+        if_return: true,
+        sequences: false,
+    };
+    input: {
+        function f(a) {
+            if (a)
+                return "";
+            console.log(a);
+        }
+    }
+    expect: {
+        function f(a) {
+            if (a)
+                return "";
+            console.log(a);
+        }
+    }
+}
+
+issue_866_2: {
+    options = {
+        conditionals: true,
+        if_return: true,
+        sequences: true,
+    }
+    input: {
+        (function() {
+            if (a)
+                if (b)
+                    c;
+                else
+                    return d;
+        })();
+    }
+    expect: {
+        (function() {
+            if (a) {
+                if (!b)
+                    return d;
+                c;
+            }
+        })();
+    }
+}

test/compress/issue-1034.js

@@ -90,13 +90,13 @@ non_hoisted_function_after_return_2a: {
         "WARN: Declarations 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: 36",
+        "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 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]",
-        "INFO: pass 1: last_count: 36, count: 18",
+        "INFO: pass 1: last_count: 35, count: 18",
     ]
 }
 
@@ -248,13 +248,13 @@ non_hoisted_function_after_return_2a_strict: {
         "WARN: Declarations 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: 47",
+        "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 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]",
-        "INFO: pass 1: last_count: 47, count: 29",
+        "INFO: pass 1: last_count: 46, count: 29",
     ]
 }
 

test/compress/issue-1052.js

@@ -16,7 +16,7 @@ multiple_functions: {
         ( function() {
             // NOTE: other compression steps will reduce this
             // down to just `window`.
-            if ( window );
+            if ( !window );
             function f() {}
             function g() {}
         } )();
@@ -38,7 +38,7 @@ single_function: {
     }
     expect: {
         ( function() {
-            if ( window );
+            if ( !window );
             function f() {}
         } )();
     }
@@ -67,7 +67,7 @@ deeply_nested: {
             // NOTE: other compression steps will reduce this
             // down to just `window`.
             if ( window )
-                if (document);
+                if ( !document );
             function f() {}
             function g() {}
             function h() {}

test/compress/issue-1105.js

@@ -151,15 +151,18 @@ Infinity_not_in_with_scope: {
         unused: true,
     }
     input: {
-        var o = { Infinity: 'oInfinity' };
+        var o = { Infinity: "FAIL" };
         var vInfinity = "Infinity";
         vInfinity = Infinity;
+        console.log(vInfinity);
     }
     expect: {
-        var o = { Infinity: 'oInfinity' }
-        var vInfinity = "Infinity"
-        vInfinity = 1/0
+        var o = { Infinity: "FAIL" };
+        var vInfinity = "Infinity";
+        vInfinity = 1/0;
+        console.log(vInfinity);
     }
+    expect_stdout: "Infinity"
 }
 
 Infinity_in_with_scope: {
@@ -167,15 +170,18 @@ Infinity_in_with_scope: {
         unused: true,
     }
     input: {
-        var o = { Infinity: 'oInfinity' };
+        var o = { Infinity: "PASS" };
         var vInfinity = "Infinity";
         with (o) { vInfinity = Infinity; }
+        console.log(vInfinity);
     }
     expect: {
-        var o = { Infinity: 'oInfinity' }
-        var vInfinity = "Infinity"
-        with (o) vInfinity = Infinity
+        var o = { Infinity: "PASS" };
+        var vInfinity = "Infinity";
+        with (o) vInfinity = Infinity;
+        console.log(vInfinity);
     }
+    expect_stdout: "PASS"
 }
 
 assorted_Infinity_NaN_undefined_in_with_scope: {

test/compress/loops.js

@@ -201,7 +201,7 @@ evaluate: {
     }
 }
 
-issue_1532: {
+issue_1532_1: {
     options = {
         evaluate: true,
         loops: true,
@@ -210,18 +210,56 @@ issue_1532: {
         function f(x, y) {
             do {
                 if (x) break;
-                foo();
+                console.log(y);
             } while (false);
         }
+        f(null, "PASS");
+        f(42, "FAIL");
+    }
+    expect: {
+        function f(x, y) {
+            for (; !x && (console.log(y), false););
+        }
+        f(null, "PASS");
+        f(42, "FAIL");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_1532_2: {
+    options = {
+        evaluate: true,
+        loops: true,
+    }
+    input: {
+        function f(x, y) {
+            do {
+                if (x) {
+                    console.log(x);
+                    break;
+                }
+                console.log(y);
+            } while (false);
+        }
+        f(null, "PASS");
+        f(42, "FAIL");
     }
     expect: {
         function f(x, y) {
             do {
-                if (x) break;
-                foo();
-            } while (false);
+                if (x) {
+                    console.log(x);
+                    break;
+                }
+            } while (console.log(y), false);
         }
+        f(null, "PASS");
+        f(42, "FAIL");
     }
+    expect_stdout: [
+        "PASS",
+        "42",
+    ]
 }
 
 issue_186: {
@@ -509,8 +547,8 @@ dead_code_condition: {
         console.log(a);
     }
     expect: {
-        var c;
         var a = 0, b = 5;
+        var c;
         a += 1, 0,
         console.log(a);
     }
@@ -1088,3 +1126,99 @@ issue_4091_2: {
     }
     expect_stdout: "undefined"
 }
+
+issue_4182_1: {
+    options = {
+        loops: true,
+    }
+    input: {
+        (function() {
+            do {
+                try {
+                    return;
+                } finally {
+                    continue;
+                }
+                console.log("FAIL");
+            } while (0);
+            console.log("PASS");
+        })();
+    }
+    expect: {
+        (function() {
+            do {
+                try {
+                    return;
+                } finally {
+                    continue;
+                }
+                console.log("FAIL");
+            } while (0);
+            console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_4182_2: {
+    options = {
+        loops: true,
+    }
+    input: {
+        (function() {
+            L: do {
+                do {
+                    try {
+                        return;
+                    } finally {
+                        continue L;
+                    }
+                    console.log("FAIL");
+                } while (0);
+                console.log("FAIL");
+            } while (0);
+            console.log("PASS");
+        })();
+    }
+    expect: {
+        (function() {
+            L: do {
+                do {
+                    try {
+                        return;
+                    } finally {
+                        continue L;
+                    }
+                } while (console.log("FAIL"), 0);
+                console.log("FAIL");
+            } while (0);
+            console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+do_continue: {
+    options = {
+        loops: true,
+    }
+    input: {
+        try {
+            do {
+                continue;
+            } while ([ A ]);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect: {
+        try {
+            do {
+                continue;
+            } while ([ A ]);
+        } catch (e) {
+            console.log("PASS");
+        }
+    }
+    expect_stdout: "PASS"
+}

test/compress/merge_vars.js

@@ -466,7 +466,7 @@ issue_4112: {
                 var o = e;
                 for (e in o);
                 var a = function() {};
-                console.log;
+                console.log(typeof a);
                 return a;
             }
         }());
@@ -479,12 +479,15 @@ issue_4112: {
                 var a = e;
                 for (e in a);
                 a = function() {};
-                console.log;
+                console.log(typeof a);
                 return a;
             }
         }());
     }
-    expect_stdout: "function"
+    expect_stdout: [
+        "function",
+        "function",
+    ]
 }
 
 issue_4115: {
@@ -2617,9 +2620,9 @@ issue_4126_1: {
             try {
                 console.log("PASS");
             } catch (e) {
-                var c = a;
+                var b = a;
             } finally {
-                var c = c;
+                var c = b;
             }
             console.log(c);
         }
@@ -2860,3 +2863,151 @@ issue_4155: {
         "function",
     ]
 }
+
+issue_4157_1: {
+    options = {
+        dead_code: true,
+        loops: true,
+        merge_vars: true,
+    }
+    input: {
+        (function() {
+            try {
+                for (var a = "FAIL"; a; a++)
+                    return;
+                var b = 0;
+            } finally {
+                console.log(b);
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            try {
+                var a = "FAIL";
+                if (a)
+                    return;
+                var b = 0;
+            } finally {
+                console.log(b);
+            }
+        })();
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4157_2: {
+    options = {
+        dead_code: true,
+        loops: true,
+        merge_vars: true,
+    }
+    input: {
+        (function() {
+            try {
+                throw "FAIL";
+            } catch (e) {
+                for (var a = e; a; a++)
+                    return;
+                var b = 0;
+            } finally {
+                console.log(b);
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            try {
+                throw "FAIL";
+            } catch (e) {
+                var a = e;
+                if (a)
+                    return;
+                var b = 0;
+            } finally {
+                console.log(b);
+            }
+        })();
+    }
+    expect_stdout: "undefined"
+}
+
+issue_4168: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        var o = {
+            f: function(a, b, c) {
+                var d = a.d;
+                var e = b.e;
+                var f = c.f;
+                this.g(arguments);
+                if (d)
+                    console.log(e, f);
+            },
+            g: function(args) {
+                console.log(args[0], args[1], args[2]);
+            },
+        };
+        o.f("PASS", true, 42);
+    }
+    expect: {
+        var o = {
+            f: function(a, b, c) {
+                var d = a.d;
+                var e = b.e;
+                var f = c.f;
+                this.g(arguments);
+                if (d)
+                    console.log(e, f);
+            },
+            g: function(args) {
+                console.log(args[0], args[1], args[2]);
+            },
+        };
+        o.f("PASS", true, 42);
+    }
+    expect_stdout: "PASS true 42"
+}
+
+issue_4168_use_strict: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        "use strict";
+        var o = {
+            f: function(a, b, c) {
+                var d = a.d;
+                var e = b.e;
+                var f = c.f;
+                this.g(arguments);
+                if (d)
+                    console.log(e, f);
+            },
+            g: function(args) {
+                console.log(args[0], args[1], args[2]);
+            },
+        };
+        o.f("PASS", true, 42);
+    }
+    expect: {
+        "use strict";
+        var o = {
+            f: function(d, e, f) {
+                var d = d.d;
+                var e = e.e;
+                var f = f.f;
+                this.g(arguments);
+                if (d)
+                    console.log(e, f);
+            },
+            g: function(args) {
+                console.log(args[0], args[1], args[2]);
+            },
+        };
+        o.f("PASS", true, 42);
+    }
+    expect_stdout: "PASS true 42"
+}

test/compress/properties.js

@@ -1123,11 +1123,7 @@ new_this: {
             }
         }.f(42);
     }
-    expect: {
-        new function(a) {
-            this.a = a;
-        }(42);
-    }
+    expect: {}
 }
 
 issue_2513: {

test/compress/pure_getters.js

@@ -848,9 +848,8 @@ collapse_vars_1_true: {
     }
     expect: {
         function f(a, b) {
-            for (;;) {
+            for (;;)
                 if (a.g() || b.p) break;
-            }
         }
     }
 }

test/compress/reduce_vars.js

@@ -5374,11 +5374,11 @@ defun_catch_4: {
         try {
             throw 42;
         } catch (a) {
+            function a() {}
             console.log(a);
         }
     }
-    expect_stdout: "42"
-    node_version: "<=4"
+    expect_stdout: true
 }
 
 defun_catch_5: {
@@ -5400,10 +5400,10 @@ defun_catch_5: {
             throw 42;
         } catch (a) {
             console.log(a);
+            function a() {}
         }
     }
-    expect_stdout: "42"
-    node_version: "<=4"
+    expect_stdout: true
 }
 
 defun_catch_6: {
@@ -7535,3 +7535,69 @@ global_assign: {
     }
     expect_stdout: "PASS"
 }
+
+issue_4188_1: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            try {
+                while (A)
+                    var a = function() {}, b = a;
+            } catch (a) {
+                console.log(function() {
+                    return typeof a;
+                }(), typeof b);
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            try {
+                while (A)
+                    var a = function() {}, b = a;
+            } catch (a) {
+                console.log(function() {
+                    return typeof a;
+                }(), typeof b);
+            }
+        })();
+    }
+    expect_stdout: "object undefined"
+}
+
+issue_4188_2: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            try {
+                throw 42;
+            } catch (a) {
+                console.log(function() {
+                    return typeof a;
+                }(), typeof b);
+            }
+            while (!console)
+                var a = function() {}, b = a;
+        })();
+    }
+    expect: {
+        (function() {
+            try {
+                throw 42;
+            } catch (a) {
+                console.log(function() {
+                    return typeof a;
+                }(), typeof b);
+            }
+            while (!console)
+                var a = function() {}, b = a;
+        })();
+    }
+    expect_stdout: "number undefined"
+}

test/compress/side_effects.js

@@ -416,3 +416,20 @@ issue_4008: {
         "PASS",
     ]
 }
+
+trim_new: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        new function(a) {
+            console.log(a);
+        }("PASS");
+    }
+    expect: {
+        (function(a) {
+            console.log(a);
+        })("PASS");
+    }
+    expect_stdout: "PASS"
+}

test/input/issue-3294/output.js

@@ -1,2 +1,2 @@
-new function(){console.log(3)};
-//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIl0sInNvdXJjZXNDb250ZW50IjpbImNsYXNzIEZvbyB7IGNvbnN0cnVjdG9yKCl7Y29uc29sZS5sb2coMSsyKTt9IH0gbmV3IEZvbygpO1xuIl0sIm5hbWVzIjpbImNvbnNvbGUiLCJsb2ciXSwibWFwcGluZ3MiOiJBQUErQyxJQUFyQyxXQUFnQkEsUUFBUUMsSUFBSSJ9
+console.log(3);
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIl0sInNvdXJjZXNDb250ZW50IjpbImNsYXNzIEZvbyB7IGNvbnN0cnVjdG9yKCl7Y29uc29sZS5sb2coMSsyKTt9IH0gbmV3IEZvbygpO1xuIl0sIm5hbWVzIjpbImNvbnNvbGUiLCJsb2ciXSwibWFwcGluZ3MiOiJBQUEwQkEsUUFBUUMsSUFBSSJ9

test/input/issue-520/output.js

@@ -1,2 +1,2 @@
-new function(){console.log(3)};
-//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIl0sInNvdXJjZXNDb250ZW50IjpbImNsYXNzIEZvbyB7IGNvbnN0cnVjdG9yKCl7Y29uc29sZS5sb2coMSsyKTt9IH0gbmV3IEZvbygpO1xuIl0sIm5hbWVzIjpbImNvbnNvbGUiLCJsb2ciXSwibWFwcGluZ3MiOiJBQUErQyxJQUFyQyxXQUFnQkEsUUFBUUMsSUFBSSJ9
+console.log(3);
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInN0ZGluIl0sInNvdXJjZXNDb250ZW50IjpbImNsYXNzIEZvbyB7IGNvbnN0cnVjdG9yKCl7Y29uc29sZS5sb2coMSsyKTt9IH0gbmV3IEZvbygpO1xuIl0sIm5hbWVzIjpbImNvbnNvbGUiLCJsb2ciXSwibWFwcGluZ3MiOiJBQUEwQkEsUUFBUUMsSUFBSSJ9

test/mocha/number-literal.js

@@ -28,4 +28,65 @@ describe("Number literals", function() {
             assert.throws(test(inputs[i]), error, inputs[i]);
         }
     });
+    it("Should parse binary, hexadecimal, octal and underscore correctly", function() {
+        [
+            "42",
+            "4_2",
+            "052",
+            "0o52",
+            "0O52",
+            "0o5_2",
+            "0x2a",
+            "0X2A",
+            "0x2_a",
+            "0b101010",
+            "0B101010",
+            "0b101_010",
+            "0.0000000042e+10",
+            "0.0000000042E+10",
+            "0.0_000000042e+10",
+            "0.0000000042e+1_0",
+            "0.000_000_004_2e+1_0",
+            "0.000_000_004_2e+1_0-0B101_010+0x2_A-0o5_2+4_2",
+        ].forEach(function(code) {
+            var result = UglifyJS.minify(code, {
+                compress: {
+                    expression: true,
+                },
+            });
+            if (result.error) throw result.error;
+            assert.strictEqual(result.code, "42;");
+        });
+    });
+    it("Should reject invalid use of underscore", function() {
+        [
+            "_42",
+            "_+42",
+            "+_42",
+        ].forEach(function(code) {
+            var node = UglifyJS.parse(code, {
+                expression: true,
+            });
+            assert.ok(!node.is_constant(), code);
+            assert.ok(!(node instanceof UglifyJS.AST_Statement), code);
+        });
+        [
+            "42_",
+            "4__2",
+            "0_52",
+            "05_2",
+            "0_o52",
+            "0o_52",
+            "0.0000000042_e10",
+            "0.0000000042e_10",
+            "0.0000000042e_+10",
+            "0.0000000042e+_10",
+        ].forEach(function(code) {
+            assert.throws(function() {
+                UglifyJS.parse(code);
+            }, function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error;
+            }, code);
+        });
+    });
 });

test/mocha/with.js

@@ -17,7 +17,7 @@ describe("With", function() {
         var ast = UglifyJS.parse("with(e) {f(1, 2)}");
         ast.figure_out_scope();
         assert.equal(ast.uses_with, true);
-        assert.equal(ast.body[0].expression.scope.uses_with, true);
-        assert.equal(ast.body[0].body.body[0].body.expression.scope.uses_with, true);
+        assert.equal(ast.body[0].expression.scope.resolve().uses_with, true);
+        assert.equal(ast.body[0].body.body[0].body.expression.scope.resolve().uses_with, true);
     });
 });

test/reduce.js

@@ -121,7 +121,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 return;
             }
             // preserve for (var xxx; ...)
-            if (parent instanceof U.AST_For && parent.init === node && node instanceof U.AST_Var) return node;
+            if (parent instanceof U.AST_For && parent.init === node && node instanceof U.AST_Definitions) return node;
             // preserve for (xxx in ...)
             if (parent instanceof U.AST_ForIn && parent.init === node) return node;
 
@@ -145,7 +145,9 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 return permute < 2 ? expr : wrap_with_console_log(expr);
             }
             else if (node instanceof U.AST_BlockStatement) {
-                if (in_list) {
+                if (in_list && node.body.filter(function(node) {
+                    return node instanceof U.AST_Const;
+                }).length == 0) {
                     node.start._permute++;
                     CHANGED = true;
                     return List.splice(node.body);
@@ -410,7 +412,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     start: {},
                 });
             }
-            else if (node instanceof U.AST_Var) {
+            else if (node instanceof U.AST_Definitions) {
                 // remove empty var statement
                 if (node.definitions.length == 0) return in_list ? List.skip : new U.AST_EmptyStatement({
                     start: {},
@@ -427,7 +429,7 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                     if (node.TYPE == "Call" && node.expression.print_to_string() == "console.log") {
                         return to_sequence(node.args);
                     }
-                    if (node instanceof U.AST_Catch) {
+                    if (node instanceof U.AST_Catch && node.argname) {
                         descend(node, this);
                         node.body.unshift(new U.AST_SimpleStatement({
                             body: wrap_with_console_log(new U.AST_SymbolRef(node.argname)),
@@ -499,7 +501,26 @@ module.exports = function reduce_test(testcase, minify_options, reduce_options)
                 log("// reduce test pass " + pass + ": " + testcase.length + " bytes");
             }
         }
-        testcase = try_beautify(testcase, minify_options, differs.unminified_result, result_cache, max_timeout);
+        var beautified = U.minify(testcase, {
+            compress: false,
+            mangle: false,
+            output: {
+                beautify: true,
+                braces: true,
+                comments: true,
+            },
+        });
+        testcase = {
+            code: testcase,
+        };
+        if (!beautified.error) {
+            diff = test_for_diff(beautified.code, minify_options, result_cache, max_timeout);
+            if (diff && !diff.timed_out && !diff.error) {
+                testcase = beautified;
+                testcase.code = "// (beautified)\n" + testcase.code;
+                differs = diff;
+            }
+        }
         var lines = [ "" ];
         if (isNaN(max_timeout)) {
             lines.push("// minify error: " + to_comment(strip_color_codes(differs.minified_result.stack)));
@@ -538,34 +559,6 @@ function trim_trailing_whitespace(value) {
     return ("" + value).replace(/\s+$/, "");
 }
 
-function try_beautify(testcase, minify_options, expected, result_cache, timeout) {
-    var result = U.minify(testcase, {
-        compress: false,
-        mangle: false,
-        output: {
-            beautify: true,
-            braces: true,
-            comments: true,
-        },
-    });
-    if (result.error) return {
-        code: testcase,
-    };
-    var toplevel = sandbox.has_toplevel(minify_options);
-    if (isNaN(timeout)) {
-        if (!U.minify(result.code, minify_options).error) return {
-            code: testcase,
-        };
-    } else {
-        var actual = run_code(result.code, toplevel, result_cache, timeout).result;
-        if (!sandbox.same_stdout(expected, actual)) return {
-            code: testcase,
-        };
-    }
-    result.code = "// (beautified)\n" + result.code;
-    return result;
-}
-
 function has_exit(fn) {
     var found = false;
     var tw = new U.TreeWalker(function(node) {

test/ufuzz/actions.js

@@ -38,6 +38,10 @@ exports.should_stop = function(callback) {
 };
 
 function read(url, callback) {
+    var done = function(reply) {
+        done = function() {};
+        callback(reply);
+    };
     var options = parse(url);
     options.headers = {
         "Authorization": "Token " + token,
@@ -49,7 +53,15 @@ function read(url, callback) {
         response.on("data", function(chunk) {
             chunks.push(chunk);
         }).on("end", function() {
-            callback(JSON.parse(chunks.join("")));
+            var reply;
+            try {
+                reply = JSON.parse(chunks.join(""))
+            } catch (e) {}
+            done(reply);
+        }).on("error", function() {
+            done();
         });
+    }).on("error", function() {
+        done();
     });
 }

test/ufuzz/index.js

@@ -275,6 +275,7 @@ var CANNOT_RETURN = true;
 var NO_DEFUN = false;
 var DEFUN_OK = true;
 var DONT_STORE = true;
+var NO_CONST = true;
 
 var VAR_NAMES = [
     "a",
@@ -312,6 +313,7 @@ var TYPEOF_OUTCOMES = [
     "crap",
 ];
 
+var block_vars = [];
 var unique_vars = [];
 var loops = 0;
 var funcs = 0;
@@ -329,6 +331,7 @@ function strictMode() {
 
 function createTopLevelCode() {
     VAR_NAMES.length = INITIAL_NAMES_LEN; // prune any previous names still in the list
+    block_vars.length = 0;
     unique_vars.length = 0;
     loops = 0;
     funcs = 0;
@@ -374,33 +377,66 @@ function filterDirective(s) {
     return s;
 }
 
+function createBlockVariables(recurmax, stmtDepth, canThrow, fn) {
+    var block_len = block_vars.length;
+    var var_len = VAR_NAMES.length;
+    var consts = [];
+    unique_vars.push("a", "b", "c", "undefined", "NaN", "Infinity");
+    while (!rng(block_vars.length > block_len ? 10 : 100)) {
+        var name = createVarName(MANDATORY, DONT_STORE);
+        consts.push(name);
+        block_vars.push(name);
+    }
+    unique_vars.length -= 6;
+    fn(function() {
+        var s = [];
+        if (consts.length) {
+            var save = VAR_NAMES;
+            VAR_NAMES = VAR_NAMES.filter(function(name) {
+                return consts.indexOf(name) < 0;
+            });
+            var len = VAR_NAMES.length;
+            s.push("const " + consts.map(function(name) {
+                var value = createExpression(recurmax, NO_COMMA, stmtDepth, canThrow);
+                VAR_NAMES.push(name);
+                return name + " = " + value;
+            }).join(", ") + ";");
+            VAR_NAMES = save.concat(VAR_NAMES.slice(len));
+        }
+        return s.join("\n");
+    });
+    block_vars.length = block_len;
+    if (consts.length) VAR_NAMES.splice(var_len, consts.length);
+}
+
 function createFunction(recurmax, allowDefun, canThrow, stmtDepth) {
     if (--recurmax < 0) { return ";"; }
     if (!STMT_COUNT_FROM_GLOBAL) stmtDepth = 0;
-    var namesLenBefore = VAR_NAMES.length;
+    var s = [];
     var name;
-    if (allowDefun || rng(5) > 0) {
-        name = "f" + funcs++;
-    } else {
-        unique_vars.push("a", "b", "c");
-        name = createVarName(MANDATORY, !allowDefun);
-        unique_vars.length -= 3;
-    }
-    var s = [
-        "function " + name + "(" + createParams() + "){",
-        strictMode()
-    ];
-    if (rng(5) === 0) {
-        // functions with functions. lower the recursion to prevent a mess.
-        s.push(createFunctions(rng(5) + 1, Math.ceil(recurmax * 0.7), DEFUN_OK, canThrow, stmtDepth));
-    } else {
-        // functions with statements
-        s.push(createStatements(3, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth));
-    }
-    s.push("}", "");
-    s = filterDirective(s).join("\n");
+    createBlockVariables(recurmax, stmtDepth, canThrow, function(defns) {
+        var namesLenBefore = VAR_NAMES.length;
+        if (allowDefun || rng(5) > 0) {
+            name = "f" + funcs++;
+        } else {
+            unique_vars.push("a", "b", "c");
+            name = createVarName(MANDATORY, !allowDefun);
+            unique_vars.length -= 3;
+        }
+        s.push("function " + name + "(" + createParams() + "){", strictMode());
+        s.push(defns());
+        if (rng(5) === 0) {
+            // functions with functions. lower the recursion to prevent a mess.
+            s.push(createFunctions(rng(5) + 1, Math.ceil(recurmax * 0.7), DEFUN_OK, canThrow, stmtDepth));
+        } else {
+            // functions with statements
+            s.push(_createStatements(3, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth));
+        }
+        s.push("}", "");
+        s = filterDirective(s).join("\n");
 
-    VAR_NAMES.length = namesLenBefore;
+        VAR_NAMES.length = namesLenBefore;
+    });
 
     if (!allowDefun) {
         // avoid "function statements" (decl inside statements)
@@ -414,7 +450,7 @@ function createFunction(recurmax, allowDefun, canThrow, stmtDepth) {
     return s + ";";
 }
 
-function createStatements(n, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) {
+function _createStatements(n, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) {
     if (--recurmax < 0) { return ";"; }
     var s = "";
     while (--n > 0) {
@@ -423,6 +459,15 @@ function createStatements(n, recurmax, canThrow, canBreak, canContinue, cannotRe
     return s;
 }
 
+function createStatements(n, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) {
+    var s = "";
+    createBlockVariables(recurmax, stmtDepth, canThrow, function(defns) {
+        s += defns() + "\n";
+        s += _createStatements(n, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth);
+    });
+    return s;
+}
+
 function enableLoopControl(flag, defaultValue) {
     return Array.isArray(flag) && flag.indexOf("") < 0 ? flag.concat("") : flag || defaultValue;
 }
@@ -496,7 +541,7 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
         var label = createLabel(canBreak, canContinue);
         canBreak = label.break || enableLoopControl(canBreak, CAN_BREAK);
         canContinue = label.continue || enableLoopControl(canContinue, CAN_CONTINUE);
-        var key = rng(10) ? "key" + loop : getVarName();
+        var key = rng(10) ? "key" + loop : getVarName(NO_CONST);
         return [
             "{var expr" + loop + " = " + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "; ",
             label.target + " for (",
@@ -571,13 +616,18 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
             // the catch var should only be accessible in the catch clause...
             // we have to do go through some trouble here to prevent leaking it
             var nameLenBefore = VAR_NAMES.length;
-            var catchName = createVarName(MANDATORY);
-            var freshCatchName = VAR_NAMES.length !== nameLenBefore;
-            if (!catch_redef) unique_vars.push(catchName);
-            s += " catch (" + catchName + ") { " + createStatements(3, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + " }";
-            // remove catch name
-            if (!catch_redef) unique_vars.pop();
-            if (freshCatchName) VAR_NAMES.splice(nameLenBefore, 1);
+            createBlockVariables(recurmax, stmtDepth, canThrow, function(defns) {
+                var catchName = createVarName(MANDATORY);
+                var freshCatchName = VAR_NAMES.length !== nameLenBefore;
+                if (!catch_redef) unique_vars.push(catchName);
+                s += " catch (" + catchName + ") { ";
+                s += defns() + "\n";
+                s += _createStatements(3, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth);
+                s += " }";
+                // remove catch name
+                if (!catch_redef) unique_vars.pop();
+                if (freshCatchName) VAR_NAMES.splice(nameLenBefore, 1);
+            });
         }
         if (n !== 0) s += " finally { " + createStatements(3, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) + " }";
         return s;
@@ -597,7 +647,7 @@ function createSwitchParts(recurmax, n, canThrow, canBreak, canContinue, cannotR
         if (hadDefault || rng(5) > 0) {
             s.push(
                 "case " + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ":",
-                createStatements(rng(3) + 1, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth),
+                _createStatements(rng(3) + 1, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth),
                 rng(10) > 0 ? " break;" : "/* fall-through */",
                 ""
             );
@@ -605,7 +655,7 @@ function createSwitchParts(recurmax, n, canThrow, canBreak, canContinue, cannotR
             hadDefault = true;
             s.push(
                 "default:",
-                createStatements(rng(3) + 1, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth),
+                _createStatements(rng(3) + 1, recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth),
                 ""
             );
         }
@@ -653,7 +703,7 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
       case p++:
         return getVarName();
       case p++:
-        return getVarName() + createAssignment() + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow);
+        return getVarName(NO_CONST) + createAssignment() + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow);
       case p++:
         return createExpression(recurmax, COMMA_OK, stmtDepth, canThrow);
       case p++:
@@ -699,19 +749,22 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
             );
             break;
           default:
-            var instantiate = rng(4) ? "new " : "";
-            s.push(
-                instantiate + "function " + name + "(){",
-                strictMode()
-            );
-            if (instantiate) for (var i = rng(4); --i >= 0;) {
-                if (rng(2)) s.push("this." + getDotKey(true) + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ";");
-                else  s.push("this[" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "]" + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ";");
-            }
-            s.push(
-                createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
-                rng(2) == 0 ? "}" : "}()"
-            );
+            createBlockVariables(recurmax, stmtDepth, canThrow, function(defns) {
+                var instantiate = rng(4) ? "new " : "";
+                s.push(
+                    instantiate + "function " + name + "(){",
+                    strictMode(),
+                    defns()
+                );
+                if (instantiate) for (var i = rng(4); --i >= 0;) {
+                    if (rng(2)) s.push("this." + getDotKey(true) + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ";");
+                    else  s.push("this[" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "]" + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ";");
+                }
+                s.push(
+                    _createStatements(rng(5) + 1, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
+                    rng(2) == 0 ? "}" : "}()"
+                );
+            });
             break;
         }
         VAR_NAMES.length = nameLenBefore;
@@ -847,28 +900,32 @@ function getDotKey(assign) {
 function createAccessor(recurmax, stmtDepth, canThrow) {
     var namesLenBefore = VAR_NAMES.length;
     var s;
-    var prop1 = getDotKey();
-    if (rng(2) == 0) {
-        s = [
-            "get " + prop1 + "(){",
-            strictMode(),
-            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 {
-        var prop2;
-        do {
-            prop2 = getDotKey();
-        } while (prop1 == prop2);
-        s = [
-            "set " + prop1 + "(" + createVarName(MANDATORY) + "){",
-            strictMode(),
-            createStatements(2, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
-            "this." + prop2 + createAssignment() + _createBinaryExpr(recurmax, COMMA_OK, stmtDepth, canThrow) + ";",
-            "},"
-        ];
-    }
+    createBlockVariables(recurmax, stmtDepth, canThrow, function(defns) {
+        var prop1 = getDotKey();
+        if (rng(2) == 0) {
+            s = [
+                "get " + prop1 + "(){",
+                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 {
+            var prop2;
+            do {
+                prop2 = getDotKey();
+            } while (prop1 == prop2);
+            s = [
+                "set " + prop1 + "(" + createVarName(MANDATORY) + "){",
+                strictMode(),
+                defns(),
+                _createStatements(2, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
+                "this." + prop2 + createAssignment() + _createBinaryExpr(recurmax, COMMA_OK, stmtDepth, canThrow) + ";",
+                "},"
+            ];
+        }
+    });
     VAR_NAMES.length = namesLenBefore;
     return filterDirective(s).join("\n");
 }
@@ -906,7 +963,7 @@ function _createSimpleBinaryExpr(recurmax, noComma, stmtDepth, canThrow) {
       case 1:
         return "(" + createUnarySafePrefix() + "(" + _createSimpleBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + "))";
       case 2:
-        assignee = getVarName();
+        assignee = getVarName(NO_CONST);
         return "(" + assignee + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ")";
       case 3:
         assignee = getVarName();
@@ -968,9 +1025,10 @@ function createUnaryPostfix() {
     return UNARY_POSTFIX[rng(UNARY_POSTFIX.length)];
 }
 
-function getVarName() {
+function getVarName(noConst) {
     // try to get a generated name reachable from current scope. default to just `a`
-    return VAR_NAMES[INITIAL_NAMES_LEN + rng(VAR_NAMES.length - INITIAL_NAMES_LEN)] || "a";
+    var name = VAR_NAMES[INITIAL_NAMES_LEN + rng(VAR_NAMES.length - INITIAL_NAMES_LEN)];
+    return !name || noConst && block_vars.indexOf(name) >= 0 ? "a" : name;
 }
 
 function createVarName(maybe, dontStore) {
@@ -980,7 +1038,7 @@ function createVarName(maybe, dontStore) {
         do {
             name = VAR_NAMES[rng(VAR_NAMES.length)];
             if (suffix) name += "_" + suffix;
-        } while (unique_vars.indexOf(name) >= 0);
+        } while (unique_vars.indexOf(name) >= 0 || block_vars.indexOf(name) >= 0);
         if (suffix && !dontStore) VAR_NAMES.push(name);
         return name;
     }
@@ -1258,10 +1316,6 @@ function patch_try_catch(orig, toplevel) {
     }
 }
 
-var fallback_options = [ JSON.stringify({
-    compress: false,
-    mangle: false
-}) ];
 var minify_options = require("./options.json").map(JSON.stringify);
 var original_code, original_result, errored;
 var uglify_code, uglify_result, ok;
@@ -1269,10 +1323,19 @@ for (var round = 1; round <= num_iterations; round++) {
     process.stdout.write(round + " of " + num_iterations + "\r");
 
     original_code = createTopLevelCode();
-    var orig_result = [ sandbox.run_code(original_code) ];
+    var orig_result = [ sandbox.run_code(original_code), sandbox.run_code(original_code, true) ];
     errored = typeof orig_result[0] != "string";
-    if (!errored) orig_result.push(sandbox.run_code(original_code, true));
-    (errored ? fallback_options : minify_options).forEach(function(options) {
+    if (errored) {
+        println("//=============================================================");
+        println("// original code");
+        try_beautify(original_code, false, orig_result[0], println);
+        println();
+        println();
+        println("original result:");
+        println(orig_result[0]);
+        println();
+    }
+    minify_options.forEach(function(options) {
         var o = JSON.parse(options);
         var toplevel = sandbox.has_toplevel(o);
         o.validate = true;
@@ -1287,13 +1350,15 @@ for (var round = 1; round <= num_iterations; round++) {
                 ok = sandbox.same_stdout(sandbox.run_code(sort_globals(original_code)), sandbox.run_code(sort_globals(uglify_code)));
             }
             // ignore numerical imprecision caused by `unsafe_math`
-            if (!ok && typeof uglify_result == "string" && o.compress && o.compress.unsafe_math) {
+            if (!ok && o.compress && o.compress.unsafe_math && typeof original_result == "string" && typeof uglify_result == "string") {
                 ok = fuzzy_match(original_result, uglify_result);
                 if (!ok) {
                     var fuzzy_result = sandbox.run_code(original_code.replace(/( - 0\.1){3}/g, " - 0.3"), toplevel);
                     ok = sandbox.same_stdout(fuzzy_result, uglify_result);
                 }
             }
+            // ignore difference in error message caused by Temporal Dead Zone
+            if (!ok && errored) ok = uglify_result.name == "ReferenceError" && original_result.name == "ReferenceError";
             // ignore difference in error message caused by `in`
             // ignore difference in depth of termination caused by infinite recursion
             if (!ok) {
@@ -1308,16 +1373,6 @@ for (var round = 1; round <= num_iterations; round++) {
             ok = errored && uglify_code.name == original_result.name;
         }
         if (verbose || (verbose_interval && !(round % INTERVAL_COUNT)) || !ok) log(options);
-        else if (errored) {
-            println("//=============================================================");
-            println("// original code");
-            try_beautify(original_code, toplevel, original_result, println);
-            println();
-            println();
-            println("original result:");
-            println(original_result);
-            println();
-        }
         if (!ok && isFinite(num_iterations)) {
             println();
             process.exit(1);

test/ufuzz/job.js

@@ -48,8 +48,10 @@ function run() {
         stderr = "";
         child.stderr.on("data", trap).pipe(process.stdout);
         log = setInterval(function() {
+            stdout = stdout.replace(/[^\r\n]+\r(?=[^\r\n]+\r)/g, "");
             var end = stdout.lastIndexOf("\r");
-            console.log(stdout.slice(stdout.lastIndexOf("\r", end - 1) + 1, end));
+            if (end < 0) return;
+            console.log(stdout.slice(0, end));
             stdout = stdout.slice(end + 1);
         }, 5 * 60 * 1000);
     }
@@ -57,7 +59,13 @@ function run() {
     function respawn() {
         console.log(stdout.replace(/[^\r\n]*\r/g, ""));
         clearInterval(log);
-        if (!iterations) spawn();
+        if (!iterations) {
+            spawn();
+        } else if (process.exitCode) {
+            tasks.forEach(function(kill) {
+                kill();
+            });
+        }
     }
 
     function trap(data) {