diff --git a/README.md b/README.md
index 8ec101f6..ac29e79a 100644
--- a/README.md
+++ b/README.md
@@ -436,16 +436,17 @@ to set `true`; it's effectively a shortcut for `foo=true`).
   compressor from discarding function names.  Useful for code relying on
   `Function.prototype.name`. See also: the `keep_fnames` [mangle option](#mangle).
 
-- `passes` -- default `1`. Number of times to run compress. Use an
-  integer argument larger than 1 to further reduce code size in some cases.
-  Note: raising the number of passes will increase uglify compress time.
+- `passes` -- default `1`. Number of times to run compress with a maximum of 3.
+  In some cases more than one pass leads to further compressed code.  Keep in
+  mind more passes will take more time.
 
 - `keep_infinity` -- default `false`. Pass `true` to prevent `Infinity` from
   being compressed into `1/0`, which may cause performance issues on Chrome.
 
 - `side_effects` -- default `false`. Pass `true` to potentially drop functions
-marked as "pure".  (A function is marked as "pure" via the comment annotation
-`/* @__PURE__ */` or `/* #__PURE__ */`)
+marked as "pure".  A function call is marked as "pure" if a comment annotation
+`/*@__PURE__*/` or `/*#__PURE__*/` immediately precedes the call. For example:
+`/*@__PURE__*/foo()`;
 
 
 ### The `unsafe` option
diff --git a/bin/uglifyjs b/bin/uglifyjs
index 635ca365..63b2f26f 100755
--- a/bin/uglifyjs
+++ b/bin/uglifyjs
@@ -367,19 +367,19 @@ var index = 0;
                     if (ex instanceof UglifyJS.JS_Parse_Error) {
                         print_error("Parse error at " + file + ":" + ex.line + "," + ex.col);
                         var col = ex.col;
-                        var line = code.split(/\r?\n/)[ex.line - (col ? 1 : 2)];
+                        var lines = code.split(/\r?\n/);
+                        var line = lines[ex.line - 1];
+                        if (!line && !col) {
+                            line = lines[ex.line - 2];
+                            col = line.length;
+                        }
                         if (line) {
                             if (col > 40) {
                                 line = line.slice(col - 40);
                                 col = 40;
                             }
-                            if (col) {
-                                print_error(line.slice(0, 80));
-                                print_error(line.slice(0, col).replace(/\S/g, " ") + "^");
-                            } else {
-                                print_error(line.slice(-40));
-                                print_error(line.slice(-40).replace(/\S/g, " ") + "^");
-                            }
+                            print_error(line.slice(0, 80));
+                            print_error(line.slice(0, col).replace(/\S/g, " ") + "^");
                         }
                         print_error(ex.stack);
                         process.exit(1);
diff --git a/lib/ast.js b/lib/ast.js
index cdf75d4d..028772f3 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -798,8 +798,8 @@ var AST_Object = DEFNODE("Object", "properties", {
 var AST_ObjectProperty = DEFNODE("ObjectProperty", "key value", {
     $documentation: "Base class for literal object properties",
     $propdoc: {
-        key: "[string] the property name converted to a string for ObjectKeyVal.  For setters and getters this is an arbitrary AST_Node.",
-        value: "[AST_Node] property value.  For setters and getters this is an AST_Function."
+        key: "[string] the property name converted to a string for ObjectKeyVal.  For setters and getters this is an AST_SymbolAccessor.",
+        value: "[AST_Node] property value.  For setters and getters this is an AST_Accessor."
     },
     _walk: function(visitor) {
         return visitor._visit(this, function(){
diff --git a/lib/compress.js b/lib/compress.js
index d0f9668c..c3adcc5e 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -316,25 +316,55 @@ merge(Compressor.prototype, {
                     safe_ids = save_ids;
                     return true;
                 }
-                var iife;
-                if (node instanceof AST_Function
-                    && !node.name
-                    && (iife = tw.parent()) instanceof AST_Call
-                    && iife.expression === node) {
-                    // Virtually turn IIFE parameters into variable definitions:
-                    //   (function(a,b) {...})(c,d) => (function() {var a=c,b=d; ...})()
-                    // So existing transformation rules can work on them.
-                    node.argnames.forEach(function(arg, i) {
-                        var d = arg.definition();
-                        if (!node.uses_arguments && d.fixed === undefined) {
-                            d.fixed = function() {
-                                return iife.args[i] || make_node(AST_Undefined, iife);
-                            };
-                            mark(d, true);
-                        } else {
-                            d.fixed = false;
-                        }
-                    });
+                if (node instanceof AST_Function) {
+                    push();
+                    var iife;
+                    if (!node.name
+                        && (iife = tw.parent()) instanceof AST_Call
+                        && iife.expression === node) {
+                        // Virtually turn IIFE parameters into variable definitions:
+                        //   (function(a,b) {...})(c,d) => (function() {var a=c,b=d; ...})()
+                        // So existing transformation rules can work on them.
+                        node.argnames.forEach(function(arg, i) {
+                            var d = arg.definition();
+                            if (!node.uses_arguments && d.fixed === undefined) {
+                                d.fixed = function() {
+                                    return iife.args[i] || make_node(AST_Undefined, iife);
+                                };
+                                mark(d, true);
+                            } else {
+                                d.fixed = false;
+                            }
+                        });
+                    }
+                    descend();
+                    pop();
+                    return true;
+                }
+                if (node instanceof AST_Accessor) {
+                    var save_ids = safe_ids;
+                    safe_ids = Object.create(null);
+                    descend();
+                    safe_ids = save_ids;
+                    return true;
+                }
+                if (node instanceof AST_Binary
+                    && (node.operator == "&&" || node.operator == "||")) {
+                    node.left.walk(tw);
+                    push();
+                    node.right.walk(tw);
+                    pop();
+                    return true;
+                }
+                if (node instanceof AST_Conditional) {
+                    node.condition.walk(tw);
+                    push();
+                    node.consequent.walk(tw);
+                    pop();
+                    push();
+                    node.alternative.walk(tw);
+                    pop();
+                    return true;
                 }
                 if (node instanceof AST_If || node instanceof AST_DWLoop) {
                     node.condition.walk(tw);
@@ -1195,12 +1225,12 @@ merge(Compressor.prototype, {
                 && !node.expression.has_side_effects(compressor);
     }
 
-    // may_eq_null()
-    // returns true if this node may evaluate to null or undefined
+    // may_throw_on_access()
+    // returns true if this node may be null, undefined or contain `AST_Accessor`
     (function(def) {
-        AST_Node.DEFMETHOD("may_eq_null", function(compressor) {
+        AST_Node.DEFMETHOD("may_throw_on_access", function(compressor) {
             var pure_getters = compressor.option("pure_getters");
-            return !pure_getters || this._eq_null(pure_getters);
+            return !pure_getters || this._throw_on_access(pure_getters);
         });
 
         function is_strict(pure_getters) {
@@ -1212,7 +1242,12 @@ merge(Compressor.prototype, {
         def(AST_Undefined, return_true);
         def(AST_Constant, return_false);
         def(AST_Array, return_false);
-        def(AST_Object, return_false);
+        def(AST_Object, function(pure_getters) {
+            if (!is_strict(pure_getters)) return false;
+            for (var i = this.properties.length; --i >=0;)
+                if (this.properties[i].value instanceof AST_Accessor) return true;
+            return false;
+        });
         def(AST_Function, return_false);
         def(AST_UnaryPostfix, return_false);
         def(AST_UnaryPrefix, function() {
@@ -1221,33 +1256,33 @@ merge(Compressor.prototype, {
         def(AST_Binary, function(pure_getters) {
             switch (this.operator) {
               case "&&":
-                return this.left._eq_null(pure_getters);
+                return this.left._throw_on_access(pure_getters);
               case "||":
-                return this.left._eq_null(pure_getters)
-                    && this.right._eq_null(pure_getters);
+                return this.left._throw_on_access(pure_getters)
+                    && this.right._throw_on_access(pure_getters);
               default:
                 return false;
             }
         })
         def(AST_Assign, function(pure_getters) {
             return this.operator == "="
-                && this.right._eq_null(pure_getters);
+                && this.right._throw_on_access(pure_getters);
         })
         def(AST_Conditional, function(pure_getters) {
-            return this.consequent._eq_null(pure_getters)
-                || this.alternative._eq_null(pure_getters);
+            return this.consequent._throw_on_access(pure_getters)
+                || this.alternative._throw_on_access(pure_getters);
         })
         def(AST_Seq, function(pure_getters) {
-            return this.cdr._eq_null(pure_getters);
+            return this.cdr._throw_on_access(pure_getters);
         });
         def(AST_SymbolRef, function(pure_getters) {
             if (this.is_undefined) return true;
             if (!is_strict(pure_getters)) return false;
             var fixed = this.fixed_value();
-            return !fixed || fixed._eq_null(pure_getters);
+            return !fixed || fixed._throw_on_access(pure_getters);
         });
     })(function(node, func) {
-        node.DEFMETHOD("_eq_null", func);
+        node.DEFMETHOD("_throw_on_access", func);
     });
 
     /* -----[ boolean/negation helpers ]----- */
@@ -1787,11 +1822,11 @@ merge(Compressor.prototype, {
             return any(this.elements, compressor);
         });
         def(AST_Dot, function(compressor){
-            return this.expression.may_eq_null(compressor)
+            return this.expression.may_throw_on_access(compressor)
                 || this.expression.has_side_effects(compressor);
         });
         def(AST_Sub, function(compressor){
-            return this.expression.may_eq_null(compressor)
+            return this.expression.may_throw_on_access(compressor)
                 || this.expression.has_side_effects(compressor)
                 || this.property.has_side_effects(compressor);
         });
@@ -2295,6 +2330,7 @@ merge(Compressor.prototype, {
             var args = trim(this.args, compressor, first_in_statement);
             return args && AST_Seq.from_array(args);
         });
+        def(AST_Accessor, return_null);
         def(AST_Function, return_null);
         def(AST_Binary, function(compressor, first_in_statement){
             var right = this.right.drop_side_effect_free(compressor);
@@ -2365,11 +2401,11 @@ merge(Compressor.prototype, {
             return values && AST_Seq.from_array(values);
         });
         def(AST_Dot, function(compressor, first_in_statement){
-            if (this.expression.may_eq_null(compressor)) return this;
+            if (this.expression.may_throw_on_access(compressor)) return this;
             return this.expression.drop_side_effect_free(compressor, first_in_statement);
         });
         def(AST_Sub, function(compressor, first_in_statement){
-            if (this.expression.may_eq_null(compressor)) return this;
+            if (this.expression.may_throw_on_access(compressor)) return this;
             var expression = this.expression.drop_side_effect_free(compressor, first_in_statement);
             if (!expression) return this.property.drop_side_effect_free(compressor, first_in_statement);
             var property = this.property.drop_side_effect_free(compressor);
diff --git a/lib/mozilla-ast.js b/lib/mozilla-ast.js
index 12b55dc5..88a2eb59 100644
--- a/lib/mozilla-ast.js
+++ b/lib/mozilla-ast.js
@@ -111,23 +111,19 @@
         },
         Property: function(M) {
             var key = M.key;
-            var name = key.type == "Identifier" ? key.name : key.value;
             var args = {
                 start    : my_start_token(key),
                 end      : my_end_token(M.value),
-                key      : name,
+                key      : key.type == "Identifier" ? key.name : key.value,
                 value    : from_moz(M.value)
             };
-            switch (M.kind) {
-              case "init":
-                return new AST_ObjectKeyVal(args);
-              case "set":
-                args.value.name = from_moz(key);
-                return new AST_ObjectSetter(args);
-              case "get":
-                args.value.name = from_moz(key);
-                return new AST_ObjectGetter(args);
-            }
+            if (M.kind == "init") return new AST_ObjectKeyVal(args);
+            args.key = new AST_SymbolAccessor({
+                name: args.key
+            });
+            args.value = new AST_Accessor(args.value);
+            if (M.kind == "get") return new AST_ObjectGetter(args);
+            if (M.kind == "set") return new AST_ObjectSetter(args);
         },
         ArrayExpression: function(M) {
             return new AST_Array({
@@ -256,10 +252,7 @@
     map("CallExpression", AST_Call, "callee>expression, arguments@args");
 
     def_to_moz(AST_Toplevel, function To_Moz_Program(M) {
-        return {
-            type: "Program",
-            body: M.body.map(to_moz)
-        };
+        return to_moz_scope("Program", M);
     });
 
     def_to_moz(AST_Defun, function To_Moz_FunctionDeclaration(M) {
@@ -267,7 +260,7 @@
             type: "FunctionDeclaration",
             id: to_moz(M.name),
             params: M.argnames.map(to_moz),
-            body: to_moz_block(M)
+            body: to_moz_scope("BlockStatement", M)
         }
     });
 
@@ -276,7 +269,7 @@
             type: "FunctionExpression",
             id: to_moz(M.name),
             params: M.argnames.map(to_moz),
-            body: to_moz_block(M)
+            body: to_moz_scope("BlockStatement", M)
         }
     });
 
@@ -382,11 +375,10 @@
     });
 
     def_to_moz(AST_ObjectProperty, function To_Moz_Property(M) {
-        var key = (
-            is_identifier(M.key)
-            ? {type: "Identifier", name: M.key}
-            : {type: "Literal", value: M.key}
-        );
+        var key = {
+            type: "Literal",
+            value: M.key instanceof AST_SymbolAccessor ? M.key.name : M.key
+        };
         var kind;
         if (M instanceof AST_ObjectKeyVal) {
             kind = "init";
@@ -547,8 +539,8 @@
         moz_to_me = new Function("U2", "my_start_token", "my_end_token", "from_moz", "return(" + moz_to_me + ")")(
             exports, my_start_token, my_end_token, from_moz
         );
-        me_to_moz = new Function("to_moz", "to_moz_block", "return(" + me_to_moz + ")")(
-            to_moz, to_moz_block
+        me_to_moz = new Function("to_moz", "to_moz_block", "to_moz_scope", "return(" + me_to_moz + ")")(
+            to_moz, to_moz_block, to_moz_scope
         );
         MOZ_TO_ME[moztype] = moz_to_me;
         def_to_moz(mytype, me_to_moz);
@@ -606,4 +598,14 @@
         };
     };
 
+    function to_moz_scope(type, node) {
+        var body = node.body.map(to_moz);
+        if (node.body[0] instanceof AST_SimpleStatement && node.body[0].body instanceof AST_String) {
+            body.unshift(to_moz(new AST_EmptyStatement(node.body[0])));
+        }
+        return {
+            type: type,
+            body: body
+        };
+    };
 })();
diff --git a/lib/parse.js b/lib/parse.js
index c34e13db..edd55e76 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -111,7 +111,7 @@ var WHITESPACE_CHARS = makePredicate(characters(" \u00a0\n\r\t\f\u000b\u200b\u20
 
 var NEWLINE_CHARS = makePredicate(characters("\n\r\u2028\u2029"));
 
-var PUNC_BEFORE_EXPRESSION = makePredicate(characters("[{(,.;:"));
+var PUNC_BEFORE_EXPRESSION = makePredicate(characters("[{(,;:"));
 
 var PUNC_CHARS = makePredicate(characters("[]{}(),;:"));
 
@@ -807,24 +807,20 @@ function parse($TEXT, options) {
         handle_regexp();
         switch (S.token.type) {
           case "string":
-            var dir = false;
-            if (S.in_directives === true) {
-                if ((is_token(peek(), "punc", ";") || peek().nlb) && S.token.raw.indexOf("\\") === -1) {
+            if (S.in_directives) {
+                tmp = peek();
+                if (S.token.raw.indexOf("\\") == -1
+                    && (tmp.nlb
+                        || is_token(tmp, "eof")
+                        || is_token(tmp, "punc", ";")
+                        || is_token(tmp, "punc", "}"))) {
                     S.input.add_directive(S.token.value);
                 } else {
                     S.in_directives = false;
                 }
             }
             var dir = S.in_directives, stat = simple_statement();
-            if (dir) {
-                return new AST_Directive({
-                    start : stat.body.start,
-                    end   : stat.body.end,
-                    quote : stat.body.quote,
-                    value : stat.body.value,
-                });
-            }
-            return stat;
+            return dir ? new AST_Directive(stat.body) : stat;
           case "num":
           case "regexp":
           case "operator":
@@ -1320,10 +1316,15 @@ function parse($TEXT, options) {
             var type = start.type;
             var name = as_property_name();
             if (type == "name" && !is("punc", ":")) {
+                var key = new AST_SymbolAccessor({
+                    start: S.token,
+                    name: as_property_name(),
+                    end: prev()
+                });
                 if (name == "get") {
                     a.push(new AST_ObjectGetter({
                         start : start,
-                        key   : as_atom_node(),
+                        key   : key,
                         value : create_accessor(),
                         end   : prev()
                     }));
@@ -1332,7 +1333,7 @@ function parse($TEXT, options) {
                 if (name == "set") {
                     a.push(new AST_ObjectSetter({
                         start : start,
-                        key   : as_atom_node(),
+                        key   : key,
                         value : create_accessor(),
                         end   : prev()
                     }));
@@ -1354,14 +1355,15 @@ function parse($TEXT, options) {
 
     function as_property_name() {
         var tmp = S.token;
-        next();
         switch (tmp.type) {
+          case "operator":
+            if (!KEYWORDS(tmp.value)) unexpected();
           case "num":
           case "string":
           case "name":
-          case "operator":
           case "keyword":
           case "atom":
+            next();
             return tmp.value;
           default:
             unexpected();
@@ -1370,16 +1372,9 @@ function parse($TEXT, options) {
 
     function as_name() {
         var tmp = S.token;
+        if (tmp.type != "name") unexpected();
         next();
-        switch (tmp.type) {
-          case "name":
-          case "operator":
-          case "keyword":
-          case "atom":
-            return tmp.value;
-          default:
-            unexpected();
-        }
+        return tmp.value;
     };
 
     function _make_symbol(type) {
@@ -1440,14 +1435,14 @@ function parse($TEXT, options) {
         if (is("operator") && UNARY_PREFIX(start.value)) {
             next();
             handle_regexp();
-            var ex = make_unary(AST_UnaryPrefix, start.value, maybe_unary(allow_calls));
+            var ex = make_unary(AST_UnaryPrefix, start, maybe_unary(allow_calls));
             ex.start = start;
             ex.end = prev();
             return ex;
         }
         var val = expr_atom(allow_calls);
         while (is("operator") && UNARY_POSTFIX(S.token.value) && !S.token.nlb) {
-            val = make_unary(AST_UnaryPostfix, S.token.value, val);
+            val = make_unary(AST_UnaryPostfix, S.token, val);
             val.start = start;
             val.end = S.token;
             next();
@@ -1455,9 +1450,10 @@ function parse($TEXT, options) {
         return val;
     };
 
-    function make_unary(ctor, op, expr) {
+    function make_unary(ctor, token, expr) {
+        var op = token.value;
         if ((op == "++" || op == "--") && !is_assignable(expr))
-            croak("Invalid use of " + op + " operator", null, ctor === AST_UnaryPrefix ? expr.start.col - 1 : null);
+            croak("Invalid use of " + op + " operator", token.line, token.col, token.pos);
         return new ctor({ operator: op, expression: expr });
     };
 
diff --git a/lib/scope.js b/lib/scope.js
index 74760e4f..bf6dbcbb 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -361,11 +361,6 @@ AST_Symbol.DEFMETHOD("unmangleable", function(options){
     return this.definition().unmangleable(options);
 });
 
-// property accessors are not mangleable
-AST_SymbolAccessor.DEFMETHOD("unmangleable", function(){
-    return true;
-});
-
 // labels are always mangleable
 AST_Label.DEFMETHOD("unmangleable", function(){
     return false;
diff --git a/package.json b/package.json
index 654b8b5c..e06f4161 100644
--- a/package.json
+++ b/package.json
@@ -33,10 +33,7 @@
     "yargs": "~3.10.0"
   },
   "devDependencies": {
-    "acorn": "~0.6.0",
-    "escodegen": "~1.3.3",
-    "esfuzz": "~0.3.1",
-    "estraverse": "~1.5.1",
+    "acorn": "~5.0.3",
     "mocha": "~2.3.4"
   },
   "optionalDependencies": {
diff --git a/test/compress/dead-code.js b/test/compress/dead-code.js
index bb72451c..af28e253 100644
--- a/test/compress/dead-code.js
+++ b/test/compress/dead-code.js
@@ -256,3 +256,19 @@ try_catch_finally: {
         "1",
     ]
 }
+
+accessor: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        ({
+            get a() {},
+            set a(v){
+                this.b = 2;
+            },
+            b: 1
+        });
+    }
+    expect: {}
+}
diff --git a/test/compress/pure_getters.js b/test/compress/pure_getters.js
index 846b53c3..0ca6a804 100644
--- a/test/compress/pure_getters.js
+++ b/test/compress/pure_getters.js
@@ -119,3 +119,62 @@ chained: {
         a.b.c;
     }
 }
+
+impure_getter_1: {
+    options = {
+        pure_getters: "strict",
+        side_effects: true,
+    }
+    input: {
+        ({
+            get a() {
+                console.log(1);
+            },
+            b: 1
+        }).a;
+        ({
+            get a() {
+                console.log(1);
+            },
+            b: 1
+        }).b;
+    }
+    expect: {
+        ({
+            get a() {
+                console.log(1);
+            },
+            b: 1
+        }).a;
+        ({
+            get a() {
+                console.log(1);
+            },
+            b: 1
+        }).b;
+    }
+    expect_stdout: "1"
+}
+
+impure_getter_2: {
+    options = {
+        pure_getters: true,
+        side_effects: true,
+    }
+    input: {
+        // will produce incorrect output because getter is not pure
+        ({
+            get a() {
+                console.log(1);
+            },
+            b: 1
+        }).a;
+        ({
+            get a() {
+                console.log(1);
+            },
+            b: 1
+        }).b;
+    }
+    expect: {}
+}
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index 767311dd..1cd8bfa0 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -2169,3 +2169,32 @@ issue_1922_2: {
     }
     expect_stdout: "1"
 }
+
+accessor: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = 1;
+        console.log({
+            get a() {
+                a = 2;
+                return a;
+            },
+            b: 1
+        }.b, a);
+    }
+    expect: {
+        var a = 1;
+        console.log({
+            get a() {
+                a = 2;
+                return a;
+            },
+            b: 1
+        }.b, a);
+    }
+    expect_stdout: "1 1"
+}
diff --git a/test/input/invalid/assign_4.js b/test/input/invalid/assign_4.js
new file mode 100644
index 00000000..d4d6b113
--- /dev/null
+++ b/test/input/invalid/assign_4.js
@@ -0,0 +1 @@
+++null
diff --git a/test/input/invalid/dot_1.js b/test/input/invalid/dot_1.js
new file mode 100644
index 00000000..7c4f3a66
--- /dev/null
+++ b/test/input/invalid/dot_1.js
@@ -0,0 +1 @@
+a.=
diff --git a/test/input/invalid/dot_2.js b/test/input/invalid/dot_2.js
new file mode 100644
index 00000000..32c027f8
--- /dev/null
+++ b/test/input/invalid/dot_2.js
@@ -0,0 +1 @@
+%.a;
diff --git a/test/input/invalid/dot_3.js b/test/input/invalid/dot_3.js
new file mode 100644
index 00000000..65573828
--- /dev/null
+++ b/test/input/invalid/dot_3.js
@@ -0,0 +1 @@
+a./();
diff --git a/test/input/invalid/object.js b/test/input/invalid/object.js
new file mode 100644
index 00000000..46216d81
--- /dev/null
+++ b/test/input/invalid/object.js
@@ -0,0 +1 @@
+console.log({%: 1});
diff --git a/test/mocha/accessorTokens-1492.js b/test/mocha/accessorTokens-1492.js
index 861414ee..d4db222d 100644
--- a/test/mocha/accessorTokens-1492.js
+++ b/test/mocha/accessorTokens-1492.js
@@ -16,7 +16,7 @@ describe("Accessor tokens", function() {
                 assert.equal(node.start.pos, 12);
                 assert.equal(node.end.endpos, 46);
 
-                assert(node.key instanceof UglifyJS.AST_SymbolRef);
+                assert(node.key instanceof UglifyJS.AST_SymbolAccessor);
                 assert.equal(node.key.start.pos, 16);
                 assert.equal(node.key.end.endpos, 22);
 
diff --git a/test/mocha/cli.js b/test/mocha/cli.js
index b956309a..d5c9585f 100644
--- a/test/mocha/cli.js
+++ b/test/mocha/cli.js
@@ -298,12 +298,87 @@ describe("bin/uglifyjs", function () {
            assert.ok(err);
            assert.strictEqual(stdout, "");
            assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
-               "Parse error at test/input/invalid/assign_3.js:1,18",
+               "Parse error at test/input/invalid/assign_3.js:1,17",
                "console.log(3 || ++this);",
-               "                  ^",
+               "                 ^",
                "SyntaxError: Invalid use of ++ operator"
            ].join("\n"));
            done();
        });
     });
+    it("Should throw syntax error (++null)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/assign_4.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/assign_4.js:1,0",
+               "++null",
+               "^",
+               "SyntaxError: Invalid use of ++ operator"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (a.=)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/dot_1.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/dot_1.js:1,2",
+               "a.=",
+               "  ^",
+               "SyntaxError: Unexpected token: operator (=)"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (%.a)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/dot_2.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/dot_2.js:1,0",
+               "%.a;",
+               "^",
+               "SyntaxError: Unexpected token: operator (%)"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (a./();)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/dot_3.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/dot_3.js:1,2",
+               "a./();",
+               "  ^",
+               "SyntaxError: Unexpected token: operator (/)"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error ({%: 1})", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/object.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/object.js:1,13",
+               "console.log({%: 1});",
+               "             ^",
+               "SyntaxError: Unexpected token: operator (%)"
+           ].join("\n"));
+           done();
+       });
+    });
 });
diff --git a/test/mocha/directives.js b/test/mocha/directives.js
index 5189f1ad..36beb567 100644
--- a/test/mocha/directives.js
+++ b/test/mocha/directives.js
@@ -351,18 +351,28 @@ describe("Directives", function() {
         var tests = [
             [
                 '"use strict";"use strict";"use strict";"use foo";"use strict";;"use sloppy";doSomething("foo");',
-                '"use strict";"use foo";doSomething("foo");'
+                '"use strict";"use foo";doSomething("foo");',
+                'function f(){ "use strict" }',
+                'function f(){ "use asm" }',
+                'function f(){ "use nondirective" }',
+                'function f(){ ;"use strict" }',
+                'function f(){ "use \n"; }',
             ],
             [
                  // Nothing gets optimised in the compressor because "use asm" is the first statement
                 '"use asm";"use\\x20strict";1+1;',
-                '"use asm";;"use strict";1+1;' // Yet, the parser noticed that "use strict" wasn't a directive
+                '"use asm";;"use strict";1+1;', // Yet, the parser noticed that "use strict" wasn't a directive
+                'function f(){"use strict"}',
+                'function f(){"use asm"}',
+                'function f(){"use nondirective"}',
+                'function f(){}',
+                'function f(){}',
             ]
         ];
 
         for (var i = 0; i < tests.length; i++) {
             assert.strictEqual(
-                uglify.minify(tests[i][0], {fromString: true, compress: {collapse_vars: true, side_effects: true}}).code,
+                uglify.minify(tests[i][0], {fromString: true}).code,
                 tests[i][1],
                 tests[i][0]
             );
diff --git a/test/mocha/getter-setter.js b/test/mocha/getter-setter.js
index 641a2026..ddd17f1f 100644
--- a/test/mocha/getter-setter.js
+++ b/test/mocha/getter-setter.js
@@ -71,7 +71,7 @@ describe("Getters and setters", function() {
         var fail = function(data) {
             return function (e) {
                 return e instanceof UglifyJS.JS_Parse_Error &&
-                    e.message === "Invalid getter/setter name: " + data.operator;
+                    e.message === "Unexpected token: operator (" + data.operator + ")";
             };
         };
 
diff --git a/test/mozilla-ast.js b/test/mozilla-ast.js
index e4c84df8..989083d4 100644
--- a/test/mozilla-ast.js
+++ b/test/mozilla-ast.js
@@ -1,103 +1,87 @@
 // Testing UglifyJS <-> SpiderMonkey AST conversion
-// through generative testing.
+"use strict";
 
-var UglifyJS = require(".."),
-    escodegen = require("escodegen"),
-    esfuzz = require("esfuzz"),
-    estraverse = require("estraverse"),
-    prefix = "\r    ";
+var acorn = require("acorn");
+var ufuzz = require("./ufuzz");
+var UglifyJS = require("..");
 
-// Normalizes input AST for UglifyJS in order to get correct comparison.
-
-function normalizeInput(ast) {
-    return estraverse.replace(ast, {
-        enter: function(node, parent) {
-            switch (node.type) {
-                // Internally mark all the properties with semi-standard type "Property".
-                case "ObjectExpression":
-                    node.properties.forEach(function (property) {
-                        property.type = "Property";
-                    });
-                    break;
-
-                // Since UglifyJS doesn"t recognize different types of property keys,
-                // decision on SpiderMonkey node type is based on check whether key
-                // can be valid identifier or not - so we do in input AST.
-                case "Property":
-                    var key = node.key;
-                    if (key.type === "Literal" && typeof key.value === "string" && UglifyJS.is_identifier(key.value)) {
-                        node.key = {
-                            type: "Identifier",
-                            name: key.value
-                        };
-                    } else if (key.type === "Identifier" && !UglifyJS.is_identifier(key.name)) {
-                        node.key = {
-                            type: "Literal",
-                            value: key.name
-                        };
-                    }
-                    break;
-
-                // UglifyJS internally flattens all the expression sequences - either
-                // to one element (if sequence contains only one element) or flat list.
-                case "SequenceExpression":
-                    node.expressions = node.expressions.reduce(function flatten(list, expr) {
-                        return list.concat(expr.type === "SequenceExpression" ? expr.expressions.reduce(flatten, []) : [expr]);
-                    }, []);
-                    if (node.expressions.length === 1) {
-                        return node.expressions[0];
-                    }
-                    break;
-            }
-        }
-    });
-}
-
-module.exports = function(options) {
-    console.log("--- UglifyJS <-> Mozilla AST conversion");
-
-    for (var counter = 0; counter < options.iterations; counter++) {
-        process.stdout.write(prefix + counter + "/" + options.iterations);
-
-        var ast1 = normalizeInput(esfuzz.generate({
-            maxDepth: options.maxDepth
-        }));
-
-        var ast2 =
-            UglifyJS
-            .AST_Node
-            .from_mozilla_ast(ast1)
-            .to_mozilla_ast();
-
-        var astPair = [
-            {name: 'expected', value: ast1},
-            {name: 'actual', value: ast2}
-        ];
-
-        var jsPair = astPair.map(function(item) {
-            return {
-                name: item.name,
-                value: escodegen.generate(item.value)
+function try_beautify(code) {
+    var beautified;
+    try {
+        beautified = UglifyJS.minify(code, {
+            fromString: true,
+            compress: false,
+            mangle: false,
+            output: {
+                beautify: true,
+                bracketize: true
             }
         });
-
-        if (jsPair[0].value !== jsPair[1].value) {
-            var fs = require("fs");
-            var acorn = require("acorn");
-
-            fs.existsSync("tmp") || fs.mkdirSync("tmp");
-
-            jsPair.forEach(function (item) {
-                var fileName = "tmp/dump_" + item.name;
-                var ast = acorn.parse(item.value);
-                fs.writeFileSync(fileName + ".js", item.value);
-                fs.writeFileSync(fileName + ".json", JSON.stringify(ast, null, 2));
-            });
-
-            process.stdout.write("\n");
-            throw new Error("Got different outputs, check out tmp/dump_*.{js,json} for codes and ASTs.");
-        }
+    } catch (ex) {
+        beautified = { error: ex };
     }
+    if (beautified.error) {
+        console.log("// !!! beautify failed !!!");
+        console.log(beautified.error.stack);
+        console.log(code);
+    } else {
+        console.log("// (beautified)");
+        console.log(beautified.code);
+    }
+}
 
-    process.stdout.write(prefix + "Probability of error is less than " + (100 / options.iterations) + "%, stopping.\n");
-};
+function test(original, estree, description) {
+    var transformed;
+    try {
+        transformed = UglifyJS.minify(estree, {
+            fromString: true,
+            compress: false,
+            mangle: false,
+            spidermonkey: true
+        });
+    } catch (ex) {
+        transformed = { error: ex };
+    }
+    if (transformed.error || original !== transformed.code) {
+        console.log("//=============================================================");
+        console.log("// !!!!!! Failed... round", round);
+        console.log("// original code");
+        try_beautify(original);
+        console.log();
+        console.log();
+        console.log("//-------------------------------------------------------------");
+        console.log("//", description);
+        if (transformed.error) {
+            console.log(transformed.error.stack);
+        } else {
+            try_beautify(transformed.code);
+        }
+        console.log("!!!!!! Failed... round", round);
+        process.exit(1);
+    }
+}
+
+var num_iterations = ufuzz.num_iterations;
+for (var round = 1; round <= num_iterations; round++) {
+    process.stdout.write(round + " of " + num_iterations + "\r");
+    var code = ufuzz.createTopLevelCode();
+    var uglified = {
+        ast: UglifyJS.parse(code),
+        code: UglifyJS.minify(code, {
+            fromString: true,
+            compress: false,
+            mangle: false
+        }).code
+    };
+    test(uglified.code, uglified.ast.to_mozilla_ast(), "AST_Node.to_mozilla_ast()");
+    try {
+        test(uglified.code, acorn.parse(code), "acorn.parse()");
+    } catch (e) {
+        console.log("//=============================================================");
+        console.log("// acorn parser failed... round", round);
+        console.log(e);
+        console.log("// original code");
+        console.log(code);
+    }
+}
+console.log();
diff --git a/test/run-tests.js b/test/run-tests.js
index f3c62e7a..02b839c2 100755
--- a/test/run-tests.js
+++ b/test/run-tests.js
@@ -23,12 +23,6 @@ mocha_tests();
 var run_sourcemaps_tests = require('./sourcemaps');
 run_sourcemaps_tests();
 
-var run_ast_conversion_tests = require("./mozilla-ast");
-
-run_ast_conversion_tests({
-    iterations: 1000
-});
-
 /* -----[ utils ]----- */
 
 function tmpl() {
diff --git a/test/sandbox.js b/test/sandbox.js
index eb9f1f0f..c155f91c 100644
--- a/test/sandbox.js
+++ b/test/sandbox.js
@@ -1,14 +1,16 @@
 var vm = require("vm");
 
-function safe_log(arg) {
+function safe_log(arg, level) {
     if (arg) switch (typeof arg) {
       case "function":
         return arg.toString();
       case "object":
         if (/Error$/.test(arg.name)) return arg.toString();
         arg.constructor.toString();
-        for (var key in arg) {
-            arg[key] = safe_log(arg[key]);
+        if (level--) for (var key in arg) {
+            if (!Object.getOwnPropertyDescriptor(arg, key).get) {
+                arg[key] = safe_log(arg[key], level);
+            }
         }
     }
     return arg;
@@ -48,7 +50,9 @@ exports.run_code = function(code) {
         ].join("\n"), {
             console: {
                 log: function() {
-                    return console.log.apply(console, [].map.call(arguments, safe_log));
+                    return console.log.apply(console, [].map.call(arguments, function(arg) {
+                        return safe_log(arg, 3);
+                    }));
                 }
             }
         }, { timeout: 5000 });
diff --git a/test/ufuzz.js b/test/ufuzz.js
index 22f17c35..afd3373a 100644
--- a/test/ufuzz.js
+++ b/test/ufuzz.js
@@ -48,8 +48,9 @@ var STMT_COUNT_FROM_GLOBAL = true; // count statement depth from nearest functio
 var num_iterations = +process.argv[2] || 1/0;
 var verbose = false; // log every generated test
 var verbose_interval = false; // log every 100 generated tests
-var verbose_error = false;
 var use_strict = false;
+var catch_redef = require.main === module;
+var generate_directive = require.main === module;
 for (var i = 2; i < process.argv.length; ++i) {
     switch (process.argv[i]) {
       case '-v':
@@ -58,9 +59,6 @@ for (var i = 2; i < process.argv.length; ++i) {
       case '-V':
         verbose_interval = true;
         break;
-      case '-E':
-        verbose_error = true;
-        break;
       case '-t':
         MAX_GENERATED_TOPLEVELS_PER_RUN = +process.argv[++i];
         if (!MAX_GENERATED_TOPLEVELS_PER_RUN) throw new Error('Must generate at least one toplevel per run');
@@ -79,6 +77,12 @@ for (var i = 2; i < process.argv.length; ++i) {
         STMT_SECOND_LEVEL_OVERRIDE = STMT_ARG_TO_ID[name];
         if (!(STMT_SECOND_LEVEL_OVERRIDE >= 0)) throw new Error('Unknown statement name; use -? to get a list');
         break;
+      case '--no-catch-redef':
+        catch_redef = false;
+        break;
+      case '--no-directive':
+        generate_directive = false;
+        break;
       case '--use-strict':
         use_strict = true;
         break;
@@ -103,11 +107,12 @@ for (var i = 2; i < process.argv.length; ++i) {
         console.log('<number>: generate this many cases (if used must be first arg)');
         console.log('-v: print every generated test case');
         console.log('-V: print every 100th generated test case');
-        console.log('-E: print generated test case with runtime error');
         console.log('-t <int>: generate this many toplevels per run (more take longer)');
         console.log('-r <int>: maximum recursion depth for generator (higher takes longer)');
         console.log('-s1 <statement name>: force the first level statement to be this one (see list below)');
         console.log('-s2 <statement name>: force the second level statement to be this one (see list below)');
+        console.log('--no-catch-redef: do not redefine catch variables');
+        console.log('--no-directive: do not generate directives');
         console.log('--use-strict: generate "use strict"');
         console.log('--stmt-depth-from-func: reset statement depth counter at each function, counts from global otherwise');
         console.log('--only-stmt <statement names>: a comma delimited white list of statements that may be generated');
@@ -192,12 +197,33 @@ var ASSIGNMENTS = [
     '=',
     '=',
     '=',
+    '=',
+    '=',
+    '=',
+    '=',
+
+    '=',
+    '=',
+    '=',
+    '=',
+    '=',
+    '=',
+    '=',
+    '=',
+    '=',
+    '=',
 
-    '==',
-    '!=',
-    '===',
-    '!==',
     '+=',
+    '+=',
+    '+=',
+    '+=',
+    '+=',
+    '+=',
+    '+=',
+    '+=',
+    '+=',
+    '+=',
+
     '-=',
     '*=',
     '/=',
@@ -207,7 +233,8 @@ var ASSIGNMENTS = [
     '<<=',
     '>>=',
     '>>>=',
-    '%=' ];
+    '%=',
+];
 
 var UNARY_SAFE = [
     '+',
@@ -276,6 +303,7 @@ var TYPEOF_OUTCOMES = [
     'symbol',
     'crap' ];
 
+var unique_vars = [];
 var loops = 0;
 var funcs = 0;
 var labels = 10000;
@@ -290,6 +318,10 @@ function strictMode() {
 }
 
 function createTopLevelCode() {
+    VAR_NAMES.length = INITIAL_NAMES_LEN; // prune any previous names still in the list
+    unique_vars.length = 0;
+    loops = 0;
+    funcs = 0;
     return [
         strictMode(),
         'var a = 100, b = 10, c = 0;',
@@ -325,33 +357,36 @@ function createArgs() {
     return args.join(', ');
 }
 
+function filterDirective(s) {
+    if (!generate_directive && !s[1] && /\("/.test(s[2])) s[2] = ';' + s[2];
+    return s;
+}
+
 function createFunction(recurmax, inGlobal, noDecl, canThrow, stmtDepth) {
     if (--recurmax < 0) { return ';'; }
     if (!STMT_COUNT_FROM_GLOBAL) stmtDepth = 0;
     var func = funcs++;
     var namesLenBefore = VAR_NAMES.length;
-    var name = (inGlobal || rng(5) > 0) ? 'f' + func : createVarName(MANDATORY, noDecl);
-    if (name === 'a' || name === 'b' || name === 'c') name = 'f' + func; // quick hack to prevent assignment to func names of being called
-    var s = '';
+    var name;
+    if (inGlobal || rng(5) > 0) name = 'f' + func;
+    else {
+        unique_vars.push('a', 'b', 'c');
+        name = createVarName(MANDATORY, noDecl);
+        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 = [
-            'function ' + name + '(' + createParams() + '){',
-            strictMode(),
-            createFunctions(rng(5) + 1, Math.ceil(recurmax * 0.7), NOT_GLOBAL, ANY_TYPE, canThrow, stmtDepth),
-            '}',
-            ''
-        ].join('\n');
+        s.push(createFunctions(rng(5) + 1, Math.ceil(recurmax * 0.7), NOT_GLOBAL, ANY_TYPE, canThrow, stmtDepth));
     } else {
         // functions with statements
-        s = [
-            'function ' + name + '(' + createParams() + '){',
-            strictMode(),
-            createStatements(3, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth),
-            '}',
-            ''
-        ].join('\n');
+        s.push(createStatements(3, recurmax, canThrow, CANNOT_BREAK, CANNOT_CONTINUE, CAN_RETURN, stmtDepth));
     }
+    s.push('}', '');
+    s = filterDirective(s).join('\n');
 
     VAR_NAMES.length = namesLenBefore;
 
@@ -359,7 +394,6 @@ function createFunction(recurmax, inGlobal, noDecl, canThrow, stmtDepth) {
     // avoid "function statements" (decl inside statements)
     else if (inGlobal || rng(10) > 0) s += 'var ' + createVarName(MANDATORY) + ' = ' + name + '(' + createArgs() + ');';
 
-
     return s;
 }
 
@@ -406,7 +440,7 @@ function getLabel(label) {
     return label && " L" + label;
 }
 
-function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth) {
+function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn, stmtDepth, target) {
     ++stmtDepth;
     var loop = ++loops;
     if (--recurmax < 0) {
@@ -414,10 +448,11 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
     }
 
     // allow to forcefully generate certain structures at first or second recursion level
-    var target = 0;
-    if (stmtDepth === 1 && STMT_FIRST_LEVEL_OVERRIDE >= 0) target = STMT_FIRST_LEVEL_OVERRIDE;
-    else if (stmtDepth === 2 && STMT_SECOND_LEVEL_OVERRIDE >= 0) target = STMT_SECOND_LEVEL_OVERRIDE;
-    else target = STMTS_TO_USE[rng(STMTS_TO_USE.length)];
+    if (target === undefined) {
+        if (stmtDepth === 1 && STMT_FIRST_LEVEL_OVERRIDE >= 0) target = STMT_FIRST_LEVEL_OVERRIDE;
+        else if (stmtDepth === 2 && STMT_SECOND_LEVEL_OVERRIDE >= 0) target = STMT_SECOND_LEVEL_OVERRIDE;
+        else target = STMTS_TO_USE[rng(STMTS_TO_USE.length)];
+    }
 
     switch (target) {
       case STMT_BLOCK:
@@ -460,20 +495,22 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
       case STMT_VAR:
         switch (rng(3)) {
           case 0:
+            unique_vars.push('c');
             var name = createVarName(MANDATORY);
-            if (name === 'c') name = 'a';
+            unique_vars.pop();
             return 'var ' + name + ';';
           case 1:
             // initializer can only have one expression
+            unique_vars.push('c');
             var name = createVarName(MANDATORY);
-            if (name === 'c') name = 'b';
+            unique_vars.pop();
             return 'var ' + name + ' = ' + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ';';
           default:
             // initializer can only have one expression
+            unique_vars.push('c');
             var n1 = createVarName(MANDATORY);
-            if (n1 === 'c') n1 = 'b';
             var n2 = createVarName(MANDATORY);
-            if (n2 === 'c') n2 = 'b';
+            unique_vars.pop();
             return 'var ' + n1 + ' = ' + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ', ' + n2 + ' = ' + createExpression(recurmax, NO_COMMA, stmtDepth, canThrow) + ';';
         }
       case STMT_RETURN_ETC:
@@ -514,8 +551,11 @@ function createStatement(recurmax, canThrow, canBreak, canContinue, cannotReturn
             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) + ' }';
-            if (freshCatchName) VAR_NAMES.splice(nameLenBefore, 1); // remove catch name
+            // 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;
@@ -593,8 +633,9 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
       case p++:
       case p++:
         var nameLenBefore = VAR_NAMES.length;
+        unique_vars.push('c');
         var name = createVarName(MAYBE); // note: this name is only accessible from _within_ the function. and immutable at that.
-        if (name == 'c') name = 'a';
+        unique_vars.pop();
         var s = [];
         switch (rng(5)) {
           case 0:
@@ -636,7 +677,7 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
                 strictMode()
             );
             if (instantiate) for (var i = rng(4); --i >= 0;) {
-                if (rng(2)) s.push('this.' + getDotKey() + createAssignment() + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ';');
+                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(
@@ -646,7 +687,7 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
             break;
         }
         VAR_NAMES.length = nameLenBefore;
-        return s.join('\n');
+        return filterDirective(s).join('\n');
       case p++:
       case p++:
         return createTypeofExpr(recurmax, stmtDepth, canThrow);
@@ -689,19 +730,19 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
             ") || " + rng(10) + ").toString()[" +
             createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "] ";
       case p++:
-        return createArrayLiteral(recurmax, COMMA_OK, stmtDepth, canThrow);
+        return createArrayLiteral(recurmax, stmtDepth, canThrow);
       case p++:
-        return createObjectLiteral(recurmax, COMMA_OK, stmtDepth, canThrow);
+        return createObjectLiteral(recurmax, stmtDepth, canThrow);
       case p++:
-        return createArrayLiteral(recurmax, COMMA_OK, stmtDepth, canThrow) + '[' +
+        return createArrayLiteral(recurmax, stmtDepth, canThrow) + '[' +
             createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ']';
       case p++:
-        return createObjectLiteral(recurmax, COMMA_OK, stmtDepth, canThrow) + '[' +
+        return createObjectLiteral(recurmax, stmtDepth, canThrow) + '[' +
             createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ']';
       case p++:
-        return createArrayLiteral(recurmax, COMMA_OK, stmtDepth, canThrow) + '.' + getDotKey();
+        return createArrayLiteral(recurmax, stmtDepth, canThrow) + '.' + getDotKey();
       case p++:
-        return createObjectLiteral(recurmax, COMMA_OK, stmtDepth, canThrow) + '.' + getDotKey();
+        return createObjectLiteral(recurmax, stmtDepth, canThrow) + '.' + getDotKey();
       case p++:
         var name = getVarName();
         return name + ' && ' + name + '[' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + ']';
@@ -713,7 +754,7 @@ function _createExpression(recurmax, noComma, stmtDepth, canThrow) {
     return _createExpression(recurmax, noComma, stmtDepth, canThrow);
 }
 
-function createArrayLiteral(recurmax, noComma, stmtDepth, canThrow) {
+function createArrayLiteral(recurmax, stmtDepth, canThrow) {
     recurmax--;
     var arr = "[";
     for (var i = rng(6); --i >= 0;) {
@@ -746,18 +787,56 @@ var KEYS = [
     "3",
 ].concat(SAFE_KEYS);
 
-function getDotKey() {
-    return SAFE_KEYS[rng(SAFE_KEYS.length)];
+function getDotKey(assign) {
+    var key;
+    do {
+        key = SAFE_KEYS[rng(SAFE_KEYS.length)];
+    } while (assign && key == "length");
+    return key;
 }
 
-function createObjectLiteral(recurmax, noComma, stmtDepth, canThrow) {
-    recurmax--;
-    var obj = "({";
-    for (var i = rng(6); --i >= 0;) {
-        var key = KEYS[rng(KEYS.length)];
-        obj += key + ":(" + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + "), ";
+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) + ';',
+            '},'
+        ];
     }
-    return obj + "})";
+    VAR_NAMES.length = namesLenBefore;
+    return filterDirective(s).join('\n');
+}
+
+function createObjectLiteral(recurmax, stmtDepth, canThrow) {
+    recurmax--;
+    var obj = ['({'];
+    for (var i = rng(6); --i >= 0;) {
+        if (rng(20) == 0) {
+            obj.push(createAccessor(recurmax, stmtDepth, canThrow));
+        } else {
+            var key = KEYS[rng(KEYS.length)];
+            obj.push(key + ':(' + createExpression(recurmax, COMMA_OK, stmtDepth, canThrow) + '),');
+        }
+    }
+    obj.push('})');
+    return obj.join('\n');
 }
 
 function createNestedBinaryExpr(recurmax, noComma, stmtDepth, canThrow) {
@@ -787,7 +866,7 @@ function _createSimpleBinaryExpr(recurmax, noComma, stmtDepth, canThrow) {
         return canThrow && rng(10) == 0 ? expr : '(' + assignee + ' && ' + expr + ')';
       case 4:
         assignee = getVarName();
-        expr = '(' + assignee + '.' + getDotKey() + createAssignment()
+        expr = '(' + assignee + '.' + getDotKey(true) + createAssignment()
             + _createBinaryExpr(recurmax, noComma, stmtDepth, canThrow) + ')';
         return canThrow && rng(10) == 0 ? expr : '(' + assignee + ' && ' + expr + ')';
       default:
@@ -844,17 +923,24 @@ function getVarName() {
 
 function createVarName(maybe, dontStore) {
     if (!maybe || rng(2)) {
-        var name = VAR_NAMES[rng(VAR_NAMES.length)];
         var suffix = rng(3);
-        if (suffix) {
-            name += '_' + suffix;
-            if (!dontStore) VAR_NAMES.push(name);
-        }
+        var name;
+        do {
+            name = VAR_NAMES[rng(VAR_NAMES.length)];
+            if (suffix) name += '_' + suffix;
+        } while (unique_vars.indexOf(name) >= 0);
+        if (suffix && !dontStore) VAR_NAMES.push(name);
         return name;
     }
     return '';
 }
 
+if (require.main !== module) {
+    exports.createTopLevelCode = createTopLevelCode;
+    exports.num_iterations = num_iterations;
+    return;
+}
+
 function try_beautify(code, result) {
     try {
         var beautified = UglifyJS.minify(code, {
@@ -978,10 +1064,6 @@ var uglify_code, uglify_result, ok;
 for (var round = 1; round <= num_iterations; round++) {
     process.stdout.write(round + " of " + num_iterations + "\r");
 
-    VAR_NAMES.length = INITIAL_NAMES_LEN; // prune any previous names still in the list
-    loops = 0;
-    funcs = 0;
-
     original_code = createTopLevelCode();
     original_result = sandbox.run_code(original_code);
     (typeof original_result != "string" ? fallback_options : minify_options).forEach(function(options) {
@@ -999,7 +1081,7 @@ for (var round = 1; round <= num_iterations; round++) {
             ok = uglify_code.name == original_result.name;
         }
         if (verbose || (verbose_interval && !(round % INTERVAL_COUNT)) || !ok) log(options);
-        else if (verbose_error && typeof original_result != "string") {
+        else if (typeof original_result != "string") {
             console.log("//=============================================================");
             console.log("// original code");
             try_beautify(original_code, original_result);