diff --git a/.github/ISSUE_TEMPLATE.md b/.github/ISSUE_TEMPLATE.md
index 31ba69d3..44afb511 100644
--- a/.github/ISSUE_TEMPLATE.md
+++ b/.github/ISSUE_TEMPLATE.md
@@ -1,7 +1,9 @@
-- Bug report or feature request?
+- Bug report or feature request? <!-- Note: sub-optimal but correct code is not a bug -->
 - `uglify-js` version (`uglifyjs -V`)
 - JavaScript input - ideally as small as possible.
 - The `uglifyjs` CLI command executed or `minify()` options used.
 - An example of JavaScript output produced and/or the error or warning.
-
-Note: the release version of `uglify-js` only supports ES5. Those wishing to minify ES6 should use the experimental [`harmony`](https://github.com/mishoo/UglifyJS2#harmony) branch.
+<!--
+    Note: the release version of uglify-js only supports ES5. Those wishing
+    to minify ES6 should use the experimental harmony branch.
+-->
diff --git a/bin/uglifyjs b/bin/uglifyjs
index e39a4b4b..635ca365 100755
--- a/bin/uglifyjs
+++ b/bin/uglifyjs
@@ -561,7 +561,7 @@ function getOptions(flag, constants) {
 
         var ast;
         try {
-            ast = UglifyJS.parse(x, { expression: true });
+            ast = UglifyJS.parse(x, { cli: true, expression: true });
         } catch(ex) {
             if (ex instanceof UglifyJS.JS_Parse_Error) {
                 print_error("Error parsing arguments for flag `" + flag + "': " + x);
diff --git a/lib/compress.js b/lib/compress.js
index a1d2244a..a5397b44 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -261,7 +261,7 @@ merge(Compressor.prototype, {
                 if (node instanceof AST_SymbolRef) {
                     var d = node.definition();
                     d.references.push(node);
-                    if (!d.fixed || !is_safe(d)
+                    if (d.fixed === undefined || !is_safe(d)
                         || is_modified(node, 0, d.fixed instanceof AST_Lambda)) {
                         d.fixed = false;
                     }
@@ -274,10 +274,10 @@ merge(Compressor.prototype, {
                         node.name.walk(suppressor);
                     } else {
                         var d = node.name.definition();
-                        if (d.fixed === undefined) {
-                            d.fixed = node.value || make_node(AST_Undefined, node);
+                        if (d.fixed == null) {
+                            d.fixed = node.value;
                             mark_as_safe(d);
-                        } else {
+                        } else if (node.value) {
                             d.fixed = false;
                         }
                     }
@@ -346,7 +346,7 @@ merge(Compressor.prototype, {
                     pop();
                     return true;
                 }
-                if (node instanceof AST_Catch) {
+                if (node instanceof AST_Catch || node instanceof AST_SwitchBranch) {
                     push();
                     descend();
                     pop();
@@ -362,7 +362,14 @@ merge(Compressor.prototype, {
 
         function is_safe(def) {
             for (var i = safe_ids.length, id = def.id; --i >= 0;) {
-                if (safe_ids[i][id]) return true;
+                if (safe_ids[i][id]) {
+                    if (def.fixed == null) {
+                        var orig = def.orig[0];
+                        if (orig instanceof AST_SymbolFunarg || orig.name == "arguments") return false;
+                        def.fixed = make_node(AST_Undefined, orig);
+                    }
+                    return true;
+                }
             }
         }
 
@@ -488,15 +495,6 @@ merge(Compressor.prototype, {
         return x;
     };
 
-    var readOnlyPrefix = makePredicate("! ~ + - void typeof");
-    function statement_to_expression(stat) {
-        if (stat.body instanceof AST_UnaryPrefix && readOnlyPrefix(stat.body.operator)) {
-            return stat.body.expression;
-        } else {
-            return stat.body;
-        }
-    }
-
     function is_iife_call(node) {
         if (node instanceof AST_Call && !(node instanceof AST_New)) {
             return node.expression instanceof AST_Function || is_iife_call(node.expression);
@@ -606,9 +604,10 @@ merge(Compressor.prototype, {
                     // Restrict var replacement to constants if side effects encountered.
                     if (side_effects_encountered |= lvalues_encountered) continue;
 
+                    var value_has_side_effects = var_decl.value.has_side_effects(compressor);
                     // Non-constant single use vars can only be replaced in same scope.
                     if (ref.scope.get_defun_scope() !== self) {
-                        side_effects_encountered |= var_decl.value.has_side_effects(compressor);
+                        side_effects_encountered |= value_has_side_effects;
                         continue;
                     }
 
@@ -635,6 +634,7 @@ merge(Compressor.prototype, {
                                 || (parent instanceof AST_If          && node !== parent.condition)
                                 || (parent instanceof AST_Conditional && node !== parent.condition)
                                 || (node instanceof AST_SymbolRef
+                                    && value_has_side_effects
                                     && !are_references_in_scope(node.definition(), self))
                                 || (parent instanceof AST_Binary
                                     && (parent.operator == "&&" || parent.operator == "||")
@@ -998,10 +998,10 @@ merge(Compressor.prototype, {
             };
             statements.forEach(function(stat){
                 if (stat instanceof AST_SimpleStatement) {
-                    if (seqLength(seq) >= compressor.sequences_limit) {
-                        push_seq();
-                    }
-                    seq.push(seq.length > 0 ? statement_to_expression(stat) : stat.body);
+                    if (seqLength(seq) >= compressor.sequences_limit) push_seq();
+                    var body = stat.body;
+                    if (seq.length > 0) body = body.drop_side_effect_free(compressor);
+                    if (body) seq.push(body);
                 } else {
                     push_seq();
                     ret.push(stat);
@@ -1050,7 +1050,7 @@ merge(Compressor.prototype, {
                                 stat.init = cons_seq(stat.init);
                             }
                             else if (!stat.init) {
-                                stat.init = statement_to_expression(prev);
+                                stat.init = prev.body.drop_side_effect_free(compressor);
                                 ret.pop();
                             }
                         } catch(ex) {
@@ -1190,9 +1190,9 @@ merge(Compressor.prototype, {
                 && this.left.is_number(compressor)
                 && this.right.is_number(compressor);
         });
-        var assign = makePredicate("-= *= /= %= &= |= ^= <<= >>= >>>=");
         def(AST_Assign, function(compressor){
-            return assign(this.operator) || this.right.is_number(compressor);
+            return binary(this.operator.slice(0, -1))
+                || this.operator == "=" && this.right.is_number(compressor);
         });
         def(AST_Seq, function(compressor){
             return this.cdr.is_number(compressor);
@@ -1231,8 +1231,10 @@ merge(Compressor.prototype, {
         node.DEFMETHOD("is_string", func);
     });
 
+    var unary_side_effects = makePredicate("delete ++ --");
+
     function isLHS(node, parent) {
-        return parent instanceof AST_Unary && (parent.operator == "++" || parent.operator == "--")
+        return parent instanceof AST_Unary && unary_side_effects(parent.operator)
             || parent instanceof AST_Assign && parent.left === node;
     }
 
@@ -1636,14 +1638,37 @@ merge(Compressor.prototype, {
             return false;
         });
 
-        def(AST_Block, function(compressor){
-            for (var i = this.body.length; --i >= 0;) {
-                if (this.body[i].has_side_effects(compressor))
+        function any(list, compressor) {
+            for (var i = list.length; --i >= 0;)
+                if (list[i].has_side_effects(compressor))
                     return true;
-            }
             return false;
-        });
+        }
 
+        def(AST_Block, function(compressor){
+            return any(this.body, compressor);
+        });
+        def(AST_Switch, function(compressor){
+            return this.expression.has_side_effects(compressor)
+                || any(this.body, compressor);
+        });
+        def(AST_Case, function(compressor){
+            return this.expression.has_side_effects(compressor)
+                || any(this.body, compressor);
+        });
+        def(AST_Try, function(compressor){
+            return any(this.body, compressor)
+                || this.bcatch && this.bcatch.has_side_effects(compressor)
+                || this.bfinally && this.bfinally.has_side_effects(compressor);
+        });
+        def(AST_If, function(compressor){
+            return this.condition.has_side_effects(compressor)
+                || this.body && this.body.has_side_effects(compressor)
+                || this.alternative && this.alternative.has_side_effects(compressor);
+        });
+        def(AST_LabeledStatement, function(compressor){
+            return this.body.has_side_effects(compressor);
+        });
         def(AST_SimpleStatement, function(compressor){
             return this.body.has_side_effects(compressor);
         });
@@ -1662,17 +1687,14 @@ merge(Compressor.prototype, {
                 || this.alternative.has_side_effects(compressor);
         });
         def(AST_Unary, function(compressor){
-            return member(this.operator, ["delete", "++", "--"])
+            return unary_side_effects(this.operator)
                 || this.expression.has_side_effects(compressor);
         });
         def(AST_SymbolRef, function(compressor){
             return this.global() && this.undeclared();
         });
         def(AST_Object, function(compressor){
-            for (var i = this.properties.length; --i >= 0;)
-                if (this.properties[i].has_side_effects(compressor))
-                    return true;
-            return false;
+            return any(this.properties, compressor);
         });
         def(AST_ObjectProperty, function(compressor){
             if (this.key instanceof AST_ObjectKeyVal &&
@@ -1681,10 +1703,7 @@ merge(Compressor.prototype, {
             return this.value.has_side_effects(compressor);
         });
         def(AST_Array, function(compressor){
-            for (var i = this.elements.length; --i >= 0;)
-                if (this.elements[i].has_side_effects(compressor))
-                    return true;
-            return false;
+            return any(this.elements, compressor);
         });
         def(AST_Dot, function(compressor){
             if (!compressor.option("pure_getters")) return true;
@@ -1927,9 +1946,13 @@ merge(Compressor.prototype, {
                 function before(node, descend, in_list) {
                     if (node instanceof AST_Function
                         && node.name
-                        && !compressor.option("keep_fnames")
-                        && !(node.name.definition().id in in_use_ids)) {
-                        node.name = null;
+                        && !compressor.option("keep_fnames")) {
+                        var def = node.name.definition();
+                        // any declarations with same name will overshadow
+                        // name of this anonymous function and can therefore
+                        // never be used anywhere
+                        if (!(def.id in in_use_ids) || def.orig.length > 1)
+                            node.name = null;
                     }
                     if (node instanceof AST_Lambda && !(node instanceof AST_Accessor)) {
                         var trim = !compressor.option("keep_fargs");
@@ -1980,9 +2003,14 @@ merge(Compressor.prototype, {
                         var def = node.definitions.filter(function(def){
                             if (def.value) def.value = def.value.transform(tt);
                             if (def.name instanceof AST_Destructuring) return true;
-                            if (def.name.definition().id in in_use_ids) return true;
-                            if (!drop_vars && def.name.definition().global) return true;
-
+                            var sym = def.name.definition();
+                            if (sym.id in in_use_ids) return true;
+                            if (!drop_vars && sym.global) return true;
+                            if (sym.orig[0] instanceof AST_SymbolCatch
+                                && sym.scope.parent_scope.find_variable(def.name).orig[0] === def.name) {
+                                def.value = def.value && def.value.drop_side_effect_free(compressor);
+                                return true;
+                            }
                             var w = {
                                 name : def.name.name,
                                 file : def.name.start.file,
@@ -2069,6 +2097,9 @@ merge(Compressor.prototype, {
                             return in_list ? MAP.splice(body) : make_node(AST_BlockStatement, node, {
                                 body: body
                             });
+                        } else if (is_empty(node.init)) {
+                            node.init = null;
+                            return node;
                         }
                     }
                     if (node instanceof AST_BlockStatement) {
@@ -2266,6 +2297,7 @@ merge(Compressor.prototype, {
             switch (this.operator) {
               case "&&":
               case "||":
+                if (right === this.right) return this;
                 var node = this.clone();
                 node.right = right;
                 return node;
@@ -2299,26 +2331,19 @@ merge(Compressor.prototype, {
             return node;
         });
         def(AST_Unary, function(compressor, first_in_statement){
-            switch (this.operator) {
-              case "delete":
-              case "++":
-              case "--":
-                return this;
-              case "typeof":
-                if (this.expression instanceof AST_SymbolRef) return null;
-              default:
-                var expression = this.expression.drop_side_effect_free(compressor, first_in_statement);
-                if (first_in_statement
-                    && this instanceof AST_UnaryPrefix
-                    && is_iife_call(expression)) {
-                    if (expression === this.expression && this.operator.length === 1) return this;
-                    return make_node(AST_UnaryPrefix, this, {
-                        operator: this.operator.length === 1 ? this.operator : "!",
-                        expression: expression
-                    });
-                }
-                return expression;
+            if (unary_side_effects(this.operator)) return this;
+            if (this.operator == "typeof" && this.expression instanceof AST_SymbolRef) return null;
+            var expression = this.expression.drop_side_effect_free(compressor, first_in_statement);
+            if (first_in_statement
+                && this instanceof AST_UnaryPrefix
+                && is_iife_call(expression)) {
+                if (expression === this.expression && this.operator.length === 1) return this;
+                return make_node(AST_UnaryPrefix, this, {
+                    operator: this.operator.length === 1 ? this.operator : "!",
+                    expression: expression
+                });
             }
+            return expression;
         });
         def(AST_SymbolRef, function() {
             return this.undeclared() ? this : null;
@@ -2526,8 +2551,8 @@ merge(Compressor.prototype, {
             return make_node(AST_SimpleStatement, self, {
                 body: make_node(AST_Conditional, self, {
                     condition   : self.condition,
-                    consequent  : statement_to_expression(self.body),
-                    alternative : statement_to_expression(self.alternative)
+                    consequent  : self.body.body,
+                    alternative : self.alternative.body
                 })
             }).optimize(compressor);
         }
@@ -2543,25 +2568,24 @@ merge(Compressor.prototype, {
                 body: make_node(AST_Binary, self, {
                     operator : "||",
                     left     : negated,
-                    right    : statement_to_expression(self.body)
+                    right    : self.body.body
                 })
             }).optimize(compressor);
             return make_node(AST_SimpleStatement, self, {
                 body: make_node(AST_Binary, self, {
                     operator : "&&",
                     left     : self.condition,
-                    right    : statement_to_expression(self.body)
+                    right    : self.body.body
                 })
             }).optimize(compressor);
         }
         if (self.body instanceof AST_EmptyStatement
-            && self.alternative
             && self.alternative instanceof AST_SimpleStatement) {
             return make_node(AST_SimpleStatement, self, {
                 body: make_node(AST_Binary, self, {
                     operator : "||",
                     left     : self.condition,
-                    right    : statement_to_expression(self.alternative)
+                    right    : self.alternative.body
                 })
             }).optimize(compressor);
         }
@@ -2611,105 +2635,93 @@ merge(Compressor.prototype, {
     });
 
     OPT(AST_Switch, function(self, compressor){
-        if (self.body.length == 0 && compressor.option("conditionals")) {
-            return make_node(AST_SimpleStatement, self, {
-                body: self.expression
-            }).transform(compressor);
+        var branch;
+        var value = self.expression.evaluate(compressor);
+        if (value !== self.expression) {
+            var expression = make_node_from_constant(value, self.expression).transform(compressor);
+            self.expression = best_of_expression(expression, self.expression);
         }
-        for(;;) {
-            var last_branch = self.body[self.body.length - 1];
-            if (last_branch) {
-                var stat = last_branch.body[last_branch.body.length - 1]; // last statement
-                if (stat instanceof AST_Break && loop_body(compressor.loopcontrol_target(stat.label)) === self)
-                    last_branch.body.pop();
-                if (last_branch instanceof AST_Default && last_branch.body.length == 0) {
-                    self.body.pop();
+        if (!compressor.option("dead_code")) return self;
+        var prev_block;
+        var decl = [];
+        var body = [];
+        var default_branch;
+        var exact_match;
+        var fallthrough;
+        for (var i = 0, len = self.body.length; i < len && !exact_match; i++) {
+            branch = self.body[i];
+            if (branch instanceof AST_Default) {
+                if (!default_branch) default_branch = branch;
+                else if (!fallthrough) {
+                    extract_declarations_from_unreachable_code(compressor, branch, decl);
+                    continue;
+                }
+            } else if (value !== self.expression) {
+                var exp = branch.expression.evaluate(compressor);
+                if (exp === value) {
+                    exact_match = branch;
+                    if (default_branch) {
+                        body.splice(body.indexOf(default_branch), 1);
+                        extract_declarations_from_unreachable_code(compressor, default_branch, decl);
+                        default_branch = null;
+                    }
+                } else if (exp !== branch.expression && !fallthrough) {
+                    extract_declarations_from_unreachable_code(compressor, branch, decl);
                     continue;
                 }
             }
-            break;
+            if (aborts(branch)) {
+                var block = make_node(AST_BlockStatement, branch, branch).print_to_string();
+                if (!fallthrough && prev_block === block) body[body.length - 1].body = [];
+                body.push(branch);
+                prev_block = block;
+                fallthrough = false;
+            } else {
+                body.push(branch);
+                prev_block = null;
+                fallthrough = true;
+            }
         }
-        var value = self.expression.evaluate(compressor);
-        out: if (value !== self.expression) try {
-            // constant expression
-            var expression = make_node_from_constant(value, self.expression);
-            self.expression = best_of_expression(expression, self.expression);
-            if (!compressor.option("dead_code")) break out;
-            var in_if = false;
-            var in_block = false;
-            var started = false;
-            var stopped = false;
-            var ruined = false;
-            var tt = new TreeTransformer(function(node, descend, in_list){
-                if (node instanceof AST_Lambda || node instanceof AST_SimpleStatement) {
-                    // no need to descend these node types
-                    return node;
-                }
-                else if (node instanceof AST_Switch && node === self) {
-                    node = node.clone();
-                    descend(node, this);
-                    return ruined ? node : make_node(AST_BlockStatement, node, {
-                        body: node.body.reduce(function(a, branch){
-                            return a.concat(branch.body);
-                        }, [])
-                    }).transform(compressor);
-                }
-                else if (node instanceof AST_If || node instanceof AST_Try) {
-                    var save = in_if;
-                    in_if = !in_block;
-                    descend(node, this);
-                    in_if = save;
-                    return node;
-                }
-                else if (node instanceof AST_StatementWithBody || node instanceof AST_Switch) {
-                    var save = in_block;
-                    in_block = true;
-                    descend(node, this);
-                    in_block = save;
-                    return node;
-                }
-                else if (node instanceof AST_Break && this.loopcontrol_target(node.label) === self) {
-                    if (in_if) {
-                        ruined = true;
-                        return node;
-                    }
-                    if (in_block) return node;
-                    stopped = true;
-                    return in_list ? MAP.skip : make_node(AST_EmptyStatement, node);
-                }
-                else if (node instanceof AST_SwitchBranch && this.parent() === self) {
-                    if (stopped) return MAP.skip;
-                    if (node instanceof AST_Case) {
-                        var exp = node.expression.evaluate(compressor);
-                        if (exp === node.expression) {
-                            // got a case with non-constant expression, baling out
-                            throw self;
-                        }
-                        if (exp === value || started) {
-                            started = true;
-                            if (aborts(node)) stopped = true;
-                            descend(node, this);
-                            return node;
-                        }
-                        return MAP.skip;
-                    }
-                    descend(node, this);
-                    return node;
-                }
+        for (; i < len && fallthrough; i++) {
+            branch = self.body[i];
+            exact_match.body = exact_match.body.concat(branch.body);
+            fallthrough = !aborts(exact_match);
+        }
+        while (i < len) extract_declarations_from_unreachable_code(compressor, self.body[i++], decl);
+        if (body.length > 0) {
+            body[0].body = decl.concat(body[0].body);
+        }
+        self.body = body;
+        while (branch = body[body.length - 1]) {
+            var stat = branch.body[branch.body.length - 1];
+            if (stat instanceof AST_Break && compressor.loopcontrol_target(stat.label) === self)
+                branch.body.pop();
+            if (branch.body.length || branch instanceof AST_Case
+                && (default_branch || branch.expression.has_side_effects(compressor))) break;
+            if (body.pop() === default_branch) default_branch = null;
+        }
+        if (body.length == 0) {
+            return make_node(AST_BlockStatement, self, {
+                body: decl.concat(make_node(AST_SimpleStatement, self.expression, {
+                    body: self.expression
+                }))
+            }).optimize(compressor);
+        }
+        if (body.length == 1 && (body[0] === exact_match || body[0] === default_branch)) {
+            var has_break = false;
+            var tw = new TreeWalker(function(node) {
+                if (has_break
+                    || node instanceof AST_Lambda
+                    || node instanceof AST_SimpleStatement) return true;
+                if (node instanceof AST_Break && tw.loopcontrol_target(node.label) === self)
+                    has_break = true;
             });
-            tt.stack = compressor.stack.slice(); // so that's able to see parent nodes
-            self = self.transform(tt);
-        } catch(ex) {
-            if (ex !== self) throw ex;
+            self.walk(tw);
+            if (!has_break) return make_node(AST_BlockStatement, self, body[0]).optimize(compressor);
         }
         return self;
     });
 
-    OPT(AST_Case, function(self, compressor){
-        self.body = tighten_body(self.body, compressor);
-        return self;
-    });
-
     OPT(AST_Try, function(self, compressor){
         self.body = tighten_body(self.body, compressor);
         return self;
@@ -3056,7 +3068,9 @@ merge(Compressor.prototype, {
                 && (self.car.operator == "++" || self.car.operator == "--")) {
                 left = self.car.expression;
             }
-            if (left) {
+            if (left
+                && !(left instanceof AST_SymbolRef
+                    && left.definition().orig[0] instanceof AST_SymbolLambda)) {
                 var parent, field;
                 var cdr = self.cdr;
                 while (true) {
@@ -3072,9 +3086,14 @@ merge(Compressor.prototype, {
                         return car;
                     }
                     if (cdr instanceof AST_Binary && !(cdr instanceof AST_Assign)) {
-                        field = cdr.left.is_constant() ? "right" : "left";
+                        if (cdr.left.is_constant()) {
+                            if (cdr.operator == "||" || cdr.operator == "&&") break;
+                            field = "right";
+                        } else {
+                            field = "left";
+                        }
                     } else if (cdr instanceof AST_Call
-                        || cdr instanceof AST_Unary && cdr.operator != "++" && cdr.operator != "--") {
+                        || cdr instanceof AST_Unary && !unary_side_effects(cdr.operator)) {
                         field = "expression";
                     } else break;
                     parent = cdr;
@@ -3139,10 +3158,10 @@ merge(Compressor.prototype, {
                 // typeof always returns a non-empty string, thus it's
                 // always true in booleans
                 compressor.warn("Boolean expression always true [{file}:{line},{col}]", self.start);
-                return make_node(AST_Seq, self, {
+                return (e instanceof AST_SymbolRef ? make_node(AST_True, self) : make_node(AST_Seq, self, {
                     car: e,
                     cdr: make_node(AST_True, self)
-                }).optimize(compressor);
+                })).optimize(compressor);
             }
         }
         // avoids infinite recursion of numerals
@@ -3424,6 +3443,7 @@ merge(Compressor.prototype, {
                         left: self.left,
                         right: self.right.expression
                     });
+                    break;
                 }
                 // -a + b => b - a
                 if (self.left instanceof AST_UnaryPrefix
@@ -3435,6 +3455,7 @@ merge(Compressor.prototype, {
                         left: self.right,
                         right: self.left.expression
                     });
+                    break;
                 }
               case "*":
                 associative = compressor.option("unsafe_math");
@@ -3698,21 +3719,30 @@ merge(Compressor.prototype, {
                 alternative: self.consequent
             });
         }
+        var condition = self.condition;
         var consequent = self.consequent;
         var alternative = self.alternative;
+        // x?x:y --> x||y
+        if (condition instanceof AST_SymbolRef
+            && consequent instanceof AST_SymbolRef
+            && condition.definition() === consequent.definition()) {
+            return make_node(AST_Binary, self, {
+                operator: "||",
+                left: condition,
+                right: alternative
+            });
+        }
+        // if (foo) exp = something; else exp = something_else;
+        //                   |
+        //                   v
+        // exp = foo ? something : something_else;
         if (consequent instanceof AST_Assign
             && alternative instanceof AST_Assign
             && consequent.operator == alternative.operator
             && consequent.left.equivalent_to(alternative.left)
-            && (!consequent.left.has_side_effects(compressor)
-                || !self.condition.has_side_effects(compressor))
-           ) {
-            /*
-             * Stuff like this:
-             * if (foo) exp = something; else exp = something_else;
-             * ==>
-             * exp = foo ? something : something_else;
-             */
+            && (!self.condition.has_side_effects(compressor)
+                || consequent.operator == "="
+                    && !consequent.left.has_side_effects(compressor))) {
             return make_node(AST_Assign, self, {
                 operator: consequent.operator,
                 left: consequent.left,
diff --git a/lib/output.js b/lib/output.js
index 7e846f7d..b174c08b 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -904,7 +904,7 @@ function OutputStream(options) {
         output.print("for");
         output.space();
         output.with_parens(function(){
-            if (self.init && !(self.init instanceof AST_EmptyStatement)) {
+            if (self.init) {
                 if (self.init instanceof AST_Definitions) {
                     self.init.print(output);
                 } else {
diff --git a/lib/parse.js b/lib/parse.js
index 4c410040..3b167044 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -852,6 +852,7 @@ function parse($TEXT, options) {
         html5_comments : true,
         bare_returns   : false,
         shebang        : true,
+        cli            : false,
     });
 
     var S = {
@@ -2418,7 +2419,7 @@ function parse($TEXT, options) {
 
     function make_unary(ctor, op, expr) {
         if ((op == "++" || op == "--") && !is_assignable(expr))
-            croak("Invalid use of " + op + " operator");
+            croak("Invalid use of " + op + " operator", null, ctor === AST_UnaryPrefix ? expr.start.col - 1 : null);
         return new ctor({ operator: op, expression: expr });
     };
 
@@ -2467,6 +2468,7 @@ function parse($TEXT, options) {
     };
 
     function is_assignable(expr) {
+        if (options.cli) return true;
         return expr instanceof AST_PropAccess || expr instanceof AST_SymbolRef;
     };
 
diff --git a/lib/scope.js b/lib/scope.js
index 87a56e0c..185ef755 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -83,9 +83,16 @@ SymbolDef.prototype = {
         }
         else if (!this.mangled_name && !this.unmangleable(options)) {
             var s = this.scope;
-            if (!options.screw_ie8 && this.orig[0] instanceof AST_SymbolLambda)
+            var sym = this.orig[0];
+            if (!options.screw_ie8 && sym instanceof AST_SymbolLambda)
                 s = s.parent_scope;
-            this.mangled_name = s.next_mangled(options, this);
+            var def;
+            if (options.screw_ie8
+                && sym instanceof AST_SymbolCatch
+                && (def = s.parent_scope.find_variable(sym))) {
+                this.mangled_name = def.mangled_name || def.name;
+            } else
+                this.mangled_name = s.next_mangled(options, this);
             if (this.global && cache) {
                 cache.set(this.name, this.mangled_name);
             }
@@ -111,8 +118,7 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
         if (node.is_block_scope()) {
             var save_scope = scope;
             scope = new AST_Scope(node);
-            scope.init_scope_vars();
-            scope.parent_scope = save_scope;
+            scope.init_scope_vars(save_scope);
             if (!(node instanceof AST_Scope)) {
                 scope.uses_with = save_scope.uses_with;
                 scope.uses_eval = save_scope.uses_eval;
@@ -129,8 +135,8 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
             return true;
         }
         if (node instanceof AST_Scope) {
-            node.init_scope_vars();
-            var save_scope = node.parent_scope = scope;
+            node.init_scope_vars(scope);
+            var save_scope = scope;
             var save_defun = defun;
             var save_labels = labels;
             defun = scope = node;
@@ -213,6 +219,14 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
             || node instanceof AST_SymbolConst) {
             var def = ((node instanceof AST_SymbolBlockDeclaration) ? scope : defun).def_variable(node, in_export, in_block);
             def.destructuring = in_destructuring;
+            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, in_export, in_block);
@@ -309,14 +323,14 @@ AST_Toplevel.DEFMETHOD("def_global", function(node){
     }
 });
 
-AST_Scope.DEFMETHOD("init_scope_vars", function(){
-    this.variables = new Dictionary(); // map name to AST_SymbolVar (variables defined in this scope; includes functions)
-    this.functions = new Dictionary(); // map name to AST_SymbolDefun (functions defined in this scope)
-    this.uses_with = false;   // will be set to true if this or some nested scope uses the `with` statement
-    this.uses_eval = false;   // will be set to true if this or nested scope uses the global `eval`
-    this.parent_scope = null; // the parent scope
-    this.enclosed = [];       // a list of variables from this or outer scope(s) that are referenced from this or inner scopes
-    this.cname = -1;          // the current index for mangling functions/variables
+AST_Scope.DEFMETHOD("init_scope_vars", function(parent_scope){
+    this.variables = new Dictionary();  // map name to AST_SymbolVar (variables defined in this scope; includes functions)
+    this.functions = new Dictionary();  // map name to AST_SymbolDefun (functions defined in this scope)
+    this.uses_with = false;             // will be set to true if this or some nested scope uses the `with` statement
+    this.uses_eval = false;             // will be set to true if this or nested scope uses the global `eval`
+    this.parent_scope = parent_scope;   // the parent scope
+    this.enclosed = [];                 // a list of variables from this or outer scope(s) that are referenced from this or inner scopes
+    this.cname = -1;                    // the current index for mangling functions/variables
 });
 
 AST_Node.DEFMETHOD("is_block_scope", function(){
@@ -339,15 +353,15 @@ AST_IterationStatement.DEFMETHOD("is_block_scope", function(){
 AST_Lambda.DEFMETHOD("init_scope_vars", function(){
     AST_Scope.prototype.init_scope_vars.apply(this, arguments);
     this.uses_arguments = false;
-
-    var symbol = new AST_VarDef({ name: "arguments", start: this.start, end: this.end });
-    var def = new SymbolDef(this, this.variables.size(), symbol);
-    this.variables.set(symbol.name, def);
+    this.def_variable(new AST_SymbolVar({
+        name: "arguments",
+        start: this.start,
+        end: this.end
+    }));
 });
 
-AST_SymbolRef.DEFMETHOD("reference", function(options) {
+AST_Symbol.DEFMETHOD("mark_enclosed", function(options) {
     var def = this.definition();
-    def.references.push(this);
     var s = this.scope;
     while (s) {
         push_uniq(s.enclosed, def);
@@ -361,6 +375,11 @@ AST_SymbolRef.DEFMETHOD("reference", function(options) {
     }
 });
 
+AST_Symbol.DEFMETHOD("reference", function(options) {
+    this.definition().references.push(this);
+    this.mark_enclosed(options);
+});
+
 AST_Scope.DEFMETHOD("find_variable", function(name){
     if (name instanceof AST_Symbol) name = name.name;
     return this.variables.get(name)
diff --git a/package.json b/package.json
index f095c793..2ada98ea 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,7 @@
   "homepage": "http://lisperator.net/uglifyjs",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "2.8.15",
+  "version": "2.8.17",
   "engines": {
     "node": ">=0.8.0"
   },
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index dad2adf2..07dcb44a 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -894,7 +894,8 @@ collapse_vars_unary: {
     }
     expect: {
         function f0(o, p) {
-            delete o[p];
+            var x = o[p];
+            delete x;
         }
         function f1(n) {
             return n > +!!n
@@ -1621,3 +1622,71 @@ issue_1631_3: {
     }
     expect_stdout: "6"
 }
+
+var_side_effects_1: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            var twice = x * 2;
+            print('Foo:', twice);
+        }
+        foo(10);
+    }
+    expect: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            print('Foo:', 2 * x);
+        }
+        foo(10);
+    }
+    expect_stdout: true
+}
+
+var_side_effects_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            var twice = x.y * 2;
+            print('Foo:', twice);
+        }
+        foo({ y: 10 });
+    }
+    expect: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            var twice = 2 * x.y;
+            print('Foo:', twice);
+        }
+        foo({ y: 10 });
+    }
+    expect_stdout: true
+}
+
+var_side_effects_3: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            var twice = x.y * 2;
+            print('Foo:', twice);
+        }
+        foo({ y: 10 });
+    }
+    expect: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            print('Foo:', 2 * x.y);
+        }
+        foo({ y: 10 });
+    }
+    expect_stdout: true
+}
diff --git a/test/compress/conditionals.js b/test/compress/conditionals.js
index 7c81cc80..e7ea2bb2 100644
--- a/test/compress/conditionals.js
+++ b/test/compress/conditionals.js
@@ -893,3 +893,72 @@ equality_conditionals_true: {
     }
     expect_stdout: true
 }
+
+issue_1645_1: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        (b = a) ? a++ + (b += a) ? b += a : b += a : b ^= a;
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        (b = a) ? (a++ + (b += a), b += a) : b ^= a;
+        console.log(a,b);
+    }
+    expect_stdout: true
+}
+
+issue_1645_2: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        var a = 0;
+        function f() {
+            return a++;
+        }
+        f() ? a += 2 : a += 4;
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        function f(){
+            return a++;
+        }
+        f() ? a += 2 : a += 4;
+        console.log(a);
+    }
+    expect_stdout: true
+}
+
+condition_symbol_matches_consequent: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        function foo(x, y) {
+            return x ? x : y;
+        }
+        function bar() {
+            return g ? g : h;
+        }
+        var g = 4;
+        var h = 5;
+        console.log(foo(3, null), foo(0, 7), foo(true, false), bar());
+    }
+    expect: {
+        function foo(x, y) {
+            return x || y;
+        }
+        function bar() {
+            return g || h;
+        }
+        var g = 4;
+        var h = 5;
+        console.log(foo(3, null), foo(0, 7), foo(true, false), bar());
+    }
+    expect_stdout: "3 7 true 4"
+}
diff --git a/test/compress/drop-unused.js b/test/compress/drop-unused.js
index d59feb52..796d5598 100644
--- a/test/compress/drop-unused.js
+++ b/test/compress/drop-unused.js
@@ -872,3 +872,143 @@ issue_1583: {
         }
     }
 }
+
+issue_1656: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    beautify = {
+        beautify: true,
+    }
+    input: {
+        for(var a=0;;);
+    }
+    expect_exact: "for (;;) ;"
+}
+
+issue_1709: {
+    options = {
+        unused: true,
+    }
+    input: {
+        console.log(
+            function x() {
+                var x = 1;
+                return x;
+            }(),
+            function y() {
+                const y = 2;
+                return y;
+            }(),
+            function z() {
+                function z() {}
+                return z;
+            }()
+        );
+    }
+    expect: {
+        console.log(
+            function() {
+                var x = 1;
+                return x;
+            }(),
+            function() {
+                const y = 2;
+                return y;
+            }(),
+            function() {
+                function z() {}
+                return z;
+            }()
+        );
+    }
+    expect_stdout: true
+}
+
+issue_1715_1: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var a = 1;
+        function f() {
+            a++;
+            try {} catch (a) {
+                var a;
+            }
+        }
+        f();
+        console.log(a);
+    }
+    expect: {
+        var a = 1;
+        function f() {
+            a++;
+            try {} catch (a) {
+                var a;
+            }
+        }
+        f();
+        console.log(a);
+    }
+    expect_stdout: "1"
+}
+
+issue_1715_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var a = 1;
+        function f() {
+            a++;
+            try {} catch (a) {
+                var a = 2;
+            }
+        }
+        f();
+        console.log(a);
+    }
+    expect: {
+        var a = 1;
+        function f() {
+            a++;
+            try {} catch (a) {
+                var a;
+            }
+        }
+        f();
+        console.log(a);
+    }
+    expect_stdout: "1"
+}
+
+issue_1715_3: {
+    options = {
+        unused: true,
+    }
+    input: {
+        var a = 1;
+        function f() {
+            a++;
+            try {} catch (a) {
+                var a = 2 + x();
+            }
+        }
+        f();
+        console.log(a);
+    }
+    expect: {
+        var a = 1;
+        function f() {
+            a++;
+            try {} catch (a) {
+                var a = x();
+            }
+        }
+        f();
+        console.log(a);
+    }
+    expect_stdout: "1"
+}
diff --git a/test/compress/evaluate.js b/test/compress/evaluate.js
index 6b8f0826..55735ee4 100644
--- a/test/compress/evaluate.js
+++ b/test/compress/evaluate.js
@@ -883,3 +883,16 @@ unsafe_charAt_noop: {
         );
     }
 }
+
+issue_1649: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log(-1 + -1);
+    }
+    expect: {
+        console.log(-2);
+    }
+    expect_stdout: "-2";
+}
diff --git a/test/compress/issue-1639.js b/test/compress/issue-1639.js
new file mode 100644
index 00000000..b6a9647f
--- /dev/null
+++ b/test/compress/issue-1639.js
@@ -0,0 +1,88 @@
+
+issue_1639_1: {
+    options = {
+        booleans: true,
+        cascade: true,
+        conditionals: true,
+        evaluate: true,
+        join_vars: true,
+        loops: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 100, b = 10;
+
+        var L1 = 5;
+        while (--L1 > 0) {
+            if ((--b), false) {
+                if (b) {
+                    var ignore = 0;
+                }
+            }
+        }
+
+        console.log(a, b);
+    }
+    expect: {
+        for (var a = 100, b = 10, L1 = 5; --L1 > 0;)
+            if (--b, !1) var ignore = 0;
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
+issue_1639_2: {
+    options = {
+        booleans: true,
+        cascade: true,
+        conditionals: true,
+        evaluate: true,
+        join_vars: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 100, b = 10;
+
+        function f19() {
+            if (++a, false)
+                if (a)
+                    if (++a);
+        }
+        f19();
+
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        function f19() {
+            ++a, 1;
+        }
+        f19(),
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
+issue_1639_3: {
+    options = {
+        booleans: true,
+        cascade: true,
+        conditionals: true,
+        evaluate: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        a++ && false && a ? 0 : 0;
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        a++,
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
diff --git a/test/compress/issue-1656.js b/test/compress/issue-1656.js
new file mode 100644
index 00000000..8b683a28
--- /dev/null
+++ b/test/compress/issue-1656.js
@@ -0,0 +1,45 @@
+f7: {
+    options = {
+        booleans: true,
+        cascade: true,
+        collapse_vars: true,
+        comparisons: true,
+        conditionals: true,
+        dead_code: true,
+        drop_debugger: true,
+        evaluate: true,
+        hoist_funs: true,
+        if_return: true,
+        join_vars: true,
+        loops: true,
+        negate_iife: true,
+        passes: 3,
+        properties: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    beautify = {
+        beautify: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        function f22464() {
+            var brake146670 = 5;
+            while (((b = a) ? !a : ~a ? null : b += a) && --brake146670 > 0) {
+            }
+        }
+        f22464();
+        console.log(a, b);
+    }
+    expect_exact: [
+        "var a = 100, b = 10;",
+        "",
+        "!function() {",
+        "    for (;b = a, !1; ) ;",
+        "}(), console.log(a, b);",
+    ]
+    expect_stdout: true
+}
diff --git a/test/compress/issue-1673.js b/test/compress/issue-1673.js
new file mode 100644
index 00000000..4628e37c
--- /dev/null
+++ b/test/compress/issue-1673.js
@@ -0,0 +1,159 @@
+side_effects_catch: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                try {
+                    throw 0;
+                } catch (e) {
+                    console.log("PASS");
+                }
+            }
+            g();
+        }
+        f();
+    }
+    expect: {
+        function f() {
+            (function() {
+                try {
+                    throw 0;
+                } catch (e) {
+                    console.log("PASS");
+                }
+            })();
+        }
+        f();
+    }
+    expect_stdout: "PASS"
+}
+
+side_effects_else: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f(x) {
+            function g() {
+                if (x);
+                else console.log("PASS");
+            }
+            g();
+        }
+        f(0);
+    }
+    expect: {
+        function f(x) {
+            (function() {
+                if (x);
+                else console.log("PASS");
+            })();
+        }
+        f(0);
+    }
+    expect_stdout: "PASS"
+}
+
+side_effects_finally: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                try {
+                } catch (e) {
+                } finally {
+                    console.log("PASS");
+                }
+            }
+            g();
+        }
+        f();
+    }
+    expect: {
+        function f() {
+            (function() {
+                try {
+                } catch (e) {
+                } finally {
+                    console.log("PASS");
+                }
+            })();
+        }
+        f();
+    }
+    expect_stdout: "PASS"
+}
+
+side_effects_label: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f(x) {
+            function g() {
+                L: {
+                    console.log("PASS");
+                    break L;
+                }
+            }
+            g();
+        }
+        f(0);
+    }
+    expect: {
+        function f(x) {
+            (function() {
+                L: {
+                    console.log("PASS");
+                    break L;
+                }
+            })();
+        }
+        f(0);
+    }
+    expect_stdout: "PASS"
+}
+
+side_effects_switch: {
+    options = {
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                switch (0) {
+                  default:
+                  case console.log("PASS"):
+                }
+            }
+            g();
+        }
+        f();
+    }
+    expect: {
+        function f() {
+            (function() {
+                switch (0) {
+                  default:
+                  case console.log("PASS"):
+                }
+            })();
+        }
+        f();
+    }
+    expect_stdout: "PASS"
+}
diff --git a/test/compress/issue-1704.js b/test/compress/issue-1704.js
new file mode 100644
index 00000000..a73f7f99
--- /dev/null
+++ b/test/compress/issue-1704.js
@@ -0,0 +1,347 @@
+mangle_catch: {
+    options = {
+        screw_ie8: true,
+        toplevel: false,
+    }
+    mangle = {
+        screw_ie8: true,
+        toplevel: false,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            throw 1;
+        } catch (args) {
+            a = "PASS";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var a="FAIL";try{throw 1}catch(o){a="PASS"}console.log(a);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_ie8: {
+    options = {
+        screw_ie8: false,
+        toplevel: false,
+    }
+    mangle = {
+        screw_ie8: false,
+        toplevel: false,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            throw 1;
+        } catch (args) {
+            a = "PASS";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var a="FAIL";try{throw 1}catch(args){a="PASS"}console.log(a);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_var: {
+    options = {
+        screw_ie8: true,
+        toplevel: false,
+    }
+    mangle = {
+        screw_ie8: true,
+        toplevel: false,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            throw 1;
+        } catch (args) {
+            var a = "PASS";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var a="FAIL";try{throw 1}catch(o){var a="PASS"}console.log(a);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_var_ie8: {
+    options = {
+        screw_ie8: false,
+        toplevel: false,
+    }
+    mangle = {
+        screw_ie8: false,
+        toplevel: false,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            throw 1;
+        } catch (args) {
+            var a = "PASS";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var a="FAIL";try{throw 1}catch(args){var a="PASS"}console.log(a);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_toplevel: {
+    options = {
+        screw_ie8: true,
+        toplevel: true,
+    }
+    mangle = {
+        screw_ie8: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            throw 1;
+        } catch (args) {
+            a = "PASS";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var o="FAIL";try{throw 1}catch(c){o="PASS"}console.log(o);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_ie8_toplevel: {
+    options = {
+        screw_ie8: false,
+        toplevel: true,
+    }
+    mangle = {
+        screw_ie8: false,
+        toplevel: true,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            throw 1;
+        } catch (args) {
+            a = "PASS";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var o="FAIL";try{throw 1}catch(c){o="PASS"}console.log(o);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_var_toplevel: {
+    options = {
+        screw_ie8: true,
+        toplevel: true,
+    }
+    mangle = {
+        screw_ie8: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            throw 1;
+        } catch (args) {
+            var a = "PASS";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var o="FAIL";try{throw 1}catch(r){var o="PASS"}console.log(o);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_var_ie8_toplevel: {
+    options = {
+        screw_ie8: false,
+        toplevel: true,
+    }
+    mangle = {
+        screw_ie8: false,
+        toplevel: true,
+    }
+    input: {
+        var a = "FAIL";
+        try {
+            throw 1;
+        } catch (args) {
+            var a = "PASS";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var o="FAIL";try{throw 1}catch(r){var o="PASS"}console.log(o);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_redef_1: {
+    options = {
+        screw_ie8: true,
+        toplevel: false,
+    }
+    mangle = {
+        screw_ie8: true,
+        toplevel: false,
+    }
+    input: {
+        var a = "PASS";
+        try {
+            throw "FAIL1";
+        } catch (a) {
+            var a = "FAIL2";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var a="PASS";try{throw"FAIL1"}catch(a){var a="FAIL2"}console.log(a);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_redef_1_ie8: {
+    options = {
+        screw_ie8: false,
+        toplevel: false,
+    }
+    mangle = {
+        screw_ie8: false,
+        toplevel: false,
+    }
+    input: {
+        var a = "PASS";
+        try {
+            throw "FAIL1";
+        } catch (a) {
+            var a = "FAIL2";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var a="PASS";try{throw"FAIL1"}catch(a){var a="FAIL2"}console.log(a);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_redef_1_toplevel: {
+    options = {
+        screw_ie8: true,
+        toplevel: true,
+    }
+    mangle = {
+        screw_ie8: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "PASS";
+        try {
+            throw "FAIL1";
+        } catch (a) {
+            var a = "FAIL2";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var o="PASS";try{throw"FAIL1"}catch(o){var o="FAIL2"}console.log(o);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_redef_1_ie8_toplevel: {
+    options = {
+        screw_ie8: false,
+        toplevel: true,
+    }
+    mangle = {
+        screw_ie8: false,
+        toplevel: true,
+    }
+    input: {
+        var a = "PASS";
+        try {
+            throw "FAIL1";
+        } catch (a) {
+            var a = "FAIL2";
+        }
+        console.log(a);
+    }
+    expect_exact: 'var o="PASS";try{throw"FAIL1"}catch(o){var o="FAIL2"}console.log(o);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_redef_2: {
+    options = {
+        screw_ie8: true,
+        toplevel: false,
+    }
+    mangle = {
+        screw_ie8: true,
+        toplevel: false,
+    }
+    input: {
+        try {
+            throw "FAIL1";
+        } catch (a) {
+            var a = "FAIL2";
+        }
+        console.log(a);
+    }
+    expect_exact: 'try{throw"FAIL1"}catch(a){var a="FAIL2"}console.log(a);'
+    expect_stdout: "undefined"
+}
+
+mangle_catch_redef_2_ie8: {
+    options = {
+        screw_ie8: false,
+        toplevel: false,
+    }
+    mangle = {
+        screw_ie8: false,
+        toplevel: false,
+    }
+    input: {
+        try {
+            throw "FAIL1";
+        } catch (a) {
+            var a = "FAIL2";
+        }
+        console.log(a);
+    }
+    expect_exact: 'try{throw"FAIL1"}catch(a){var a="FAIL2"}console.log(a);'
+    expect_stdout: "undefined"
+}
+
+mangle_catch_redef_2_toplevel: {
+    options = {
+        screw_ie8: true,
+        toplevel: true,
+    }
+    mangle = {
+        screw_ie8: true,
+        toplevel: true,
+    }
+    input: {
+        try {
+            throw "FAIL1";
+        } catch (a) {
+            var a = "FAIL2";
+        }
+        console.log(a);
+    }
+    expect_exact: 'try{throw"FAIL1"}catch(o){var o="FAIL2"}console.log(o);'
+    expect_stdout: "undefined"
+}
+
+mangle_catch_redef_2_ie8_toplevel: {
+    options = {
+        screw_ie8: false,
+        toplevel: true,
+    }
+    mangle = {
+        screw_ie8: false,
+        toplevel: true,
+    }
+    input: {
+        try {
+            throw "FAIL1";
+        } catch (a) {
+            var a = "FAIL2";
+        }
+        console.log(a);
+    }
+    expect_exact: 'try{throw"FAIL1"}catch(o){var o="FAIL2"}console.log(o);'
+    expect_stdout: "undefined"
+}
diff --git a/test/compress/loops.js b/test/compress/loops.js
index b55c6162..c8d77840 100644
--- a/test/compress/loops.js
+++ b/test/compress/loops.js
@@ -440,3 +440,21 @@ issue_186_beautify_bracketize_ie8: {
         '}',
     ]
 }
+
+issue_1648: {
+    options = {
+        join_vars: true,
+        loops: true,
+        passes: 2,
+        sequences: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            x();
+            var b = 1;
+            while (1);
+        }
+    }
+    expect_exact: "function f(){for(x();1;);}"
+}
diff --git a/test/compress/negate-iife.js b/test/compress/negate-iife.js
index e9ad37db..343e8e16 100644
--- a/test/compress/negate-iife.js
+++ b/test/compress/negate-iife.js
@@ -353,8 +353,9 @@ issue_1254_negate_iife_nested: {
 
 issue_1288: {
     options = {
-        negate_iife: true,
         conditionals: true,
+        negate_iife: true,
+        side_effects: false,
     };
     input: {
         if (w) ;
@@ -374,11 +375,11 @@ issue_1288: {
             })(0);
     }
     expect: {
-        w || function f() {}();
-        x || function() {
+        w || !function f() {}();
+        x || !function() {
             x = {};
         }();
-        y ? function() {}() : function(z) {
+        y ? !function() {}() : !function(z) {
             return z;
         }(0);
     }
diff --git a/test/compress/numbers.js b/test/compress/numbers.js
index 0b40bb9c..ea439ecc 100644
--- a/test/compress/numbers.js
+++ b/test/compress/numbers.js
@@ -153,3 +153,18 @@ evaluate_4: {
         );
     }
 }
+
+issue_1710: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        var x = {};
+        console.log((x += 1) + -x);
+    }
+    expect: {
+        var x = {};
+        console.log((x += 1) + -x);
+    }
+    expect_stdout: true
+}
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index 3d5612cf..87942ab9 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -425,7 +425,7 @@ iife_new: {
     expect_stdout: true
 }
 
-multi_def: {
+multi_def_1: {
     options = {
         evaluate: true,
         reduce_vars: true,
@@ -435,7 +435,7 @@ multi_def: {
             if (a)
                 var b = 1;
             else
-                var b = 2
+                var b = 2;
             console.log(b + 1);
         }
     }
@@ -444,7 +444,7 @@ multi_def: {
             if (a)
                 var b = 1;
             else
-                var b = 2
+                var b = 2;
             console.log(b + 1);
         }
     }
@@ -479,6 +479,33 @@ multi_def_2: {
     }
 }
 
+multi_def_3: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        function f(a) {
+            var b = 2;
+            if (a)
+                var b;
+            else
+                var b;
+            console.log(b + 1);
+        }
+    }
+    expect: {
+        function f(a) {
+            var b = 2;
+            if (a)
+                var b;
+            else
+                var b;
+            console.log(3);
+        }
+    }
+}
+
 use_before_var: {
     options = {
         evaluate: true,
@@ -1364,3 +1391,466 @@ issue_1606: {
         }
     }
 }
+
+issue_1670_1: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        evaluate: true,
+        dead_code: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function f() {
+            switch (1) {
+              case 0:
+                var a = true;
+                break;
+              default:
+                if (typeof a === "undefined") console.log("PASS");
+                else console.log("FAIL");
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            var a;
+            void 0 === a ? console.log("PASS") : console.log("FAIL");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_1670_2: {
+    options = {
+        conditionals: true,
+        evaluate: true,
+        dead_code: true,
+        passes: 2,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function f() {
+            switch (1) {
+              case 0:
+                var a = true;
+                break;
+              default:
+                if (typeof a === "undefined") console.log("PASS");
+                else console.log("FAIL");
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_1670_3: {
+    options = {
+        comparisons: true,
+        conditionals: true,
+        evaluate: true,
+        dead_code: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function f() {
+            switch (1) {
+              case 0:
+                var a = true;
+                break;
+              case 1:
+                if (typeof a === "undefined") console.log("PASS");
+                else console.log("FAIL");
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            var a;
+            void 0 === a ? console.log("PASS") : console.log("FAIL");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_1670_4: {
+    options = {
+        conditionals: true,
+        evaluate: true,
+        dead_code: true,
+        passes: 2,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function f() {
+            switch (1) {
+              case 0:
+                var a = true;
+                break;
+              case 1:
+                if (typeof a === "undefined") console.log("PASS");
+                else console.log("FAIL");
+            }
+        })();
+    }
+    expect: {
+        (function() {
+            console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_1670_5: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            switch (1) {
+              case a:
+                console.log(a);
+                break;
+              default:
+                console.log(2);
+                break;
+            }
+        })(1);
+    }
+    expect: {
+        (function() {
+            console.log(1);
+        })();
+    }
+    expect_stdout: "1"
+}
+
+issue_1670_6: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            switch (1) {
+              case a = 1:
+                console.log(a);
+                break;
+              default:
+                console.log(2);
+                break;
+            }
+        })(1);
+    }
+    expect: {
+        (function(a) {
+            switch (1) {
+              case a = 1:
+                console.log(a);
+                break;
+              default:
+                console.log(2);
+            }
+        })(1);
+    }
+    expect_stdout: "1"
+}
+
+unary_delete: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var b = 10;
+        function f() {
+            var a;
+            if (delete a) b--;
+        }
+        f();
+        console.log(b);
+    }
+    expect: {
+        var b = 10;
+        function f() {
+            var a;
+            if (delete a) b--;
+        }
+        f();
+        console.log(b);
+    }
+    expect_stdout: true
+}
+
+redefine_arguments_1: {
+    options = {
+        evaluate: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var arguments;
+            return typeof arguments;
+        }
+        function g() {
+            var arguments = 42;
+            return typeof arguments;
+        }
+        function h(x) {
+            var arguments = x;
+            return typeof arguments;
+        }
+        console.log(f(), g(), h());
+    }
+    expect: {
+        function f() {
+            var arguments;
+            return typeof arguments;
+        }
+        function g() {
+            return"number";
+        }
+        function h(x) {
+            var arguments = x;
+            return typeof arguments;
+        }
+        console.log(f(), g(), h());
+    }
+    expect_stdout: "object number undefined"
+}
+
+redefine_arguments_2: {
+    options = {
+        evaluate: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var arguments;
+            return typeof arguments;
+        }
+        function g() {
+            var arguments = 42;
+            return typeof arguments;
+        }
+        function h(x) {
+            var arguments = x;
+            return typeof arguments;
+        }
+        console.log(f(), g(), h());
+    }
+    expect: {
+        console.log(function() {
+            var arguments;
+            return typeof arguments;
+        }(), function() {
+            return"number";
+        }(), function(x) {
+            var arguments = x;
+            return typeof arguments;
+        }());
+    }
+    expect_stdout: "object number undefined"
+}
+
+redefine_arguments_3: {
+    options = {
+        evaluate: true,
+        keep_fargs: false,
+        passes: 3,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            var arguments;
+            return typeof arguments;
+        }
+        function g() {
+            var arguments = 42;
+            return typeof arguments;
+        }
+        function h(x) {
+            var arguments = x;
+            return typeof arguments;
+        }
+        console.log(f(), g(), h());
+    }
+    expect: {
+        console.log(function() {
+            var arguments;
+            return typeof arguments;
+        }(), "number", "undefined");
+    }
+    expect_stdout: "object number undefined"
+}
+
+redefine_farg_1: {
+    options = {
+        evaluate: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            var a;
+            return typeof a;
+        }
+        function g(a) {
+            var a = 42;
+            return typeof a;
+        }
+        function h(a, b) {
+            var a = b;
+            return typeof a;
+        }
+        console.log(f([]), g([]), h([]));
+    }
+    expect: {
+        function f(a) {
+            var a;
+            return typeof a;
+        }
+        function g() {
+            return"number";
+        }
+        function h(a, b) {
+            var a = b;
+            return typeof a;
+        }
+        console.log(f([]), g([]), h([]));
+    }
+    expect_stdout: "object number undefined"
+}
+
+redefine_farg_2: {
+    options = {
+        evaluate: true,
+        keep_fargs: false,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            var a;
+            return typeof a;
+        }
+        function g(a) {
+            var a = 42;
+            return typeof a;
+        }
+        function h(a, b) {
+            var a = b;
+            return typeof a;
+        }
+        console.log(f([]), g([]), h([]));
+    }
+    expect: {
+        console.log(function(a) {
+            var a;
+            return typeof a;
+        }([]), function() {
+            return "number";
+        }(),function(a, b) {
+            var a = b;
+            return typeof a;
+        }([]));
+    }
+    expect_stdout: "object number undefined"
+}
+
+redefine_farg_3: {
+    options = {
+        evaluate: true,
+        keep_fargs: false,
+        passes: 3,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f(a) {
+            var a;
+            return typeof a;
+        }
+        function g(a) {
+            var a = 42;
+            return typeof a;
+        }
+        function h(a, b) {
+            var a = b;
+            return typeof a;
+        }
+        console.log(f([]), g([]), h([]));
+    }
+    expect: {
+        console.log(function(a) {
+            var a;
+            return typeof a;
+        }([]), "number", function(a) {
+            var a = void 0;
+            return typeof a;
+        }([]));
+    }
+    expect_stdout: "object number undefined"
+}
+
+delay_def: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            return a;
+            var a;
+        }
+        function g() {
+            return a;
+            var a = 1;
+        }
+        console.log(f(), g());
+    }
+    expect: {
+        function f() {
+            return a;
+            var a;
+        }
+        function g() {
+            return a;
+            var a = 1;
+        }
+        console.log(f(), g());
+    }
+    expect_stdout: true
+}
diff --git a/test/compress/sequences.js b/test/compress/sequences.js
index 49b61ae0..f1fa0e87 100644
--- a/test/compress/sequences.js
+++ b/test/compress/sequences.js
@@ -306,3 +306,137 @@ unsafe_undefined: {
         }
     }
 }
+
+issue_1685: {
+    options = {
+        cascade: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        function f() {
+            var a = (a--, delete a && --b);
+        }
+        f();
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        function f() {
+            var a = (a--, delete a && --b);
+        }
+        f();
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
+func_def_1: {
+    options = {
+        cascade: true,
+        side_effects: true,
+    }
+    input: {
+        function f() {
+            return f = 0, !!f;
+        }
+        console.log(f());
+    }
+    expect: {
+        function f() {
+            return !!(f = 0);
+        }
+        console.log(f());
+    }
+    expect_stdout: "false"
+}
+
+func_def_2: {
+    options = {
+        cascade: true,
+        side_effects: true,
+    }
+    input: {
+        console.log(function f() {
+            return f = 0, !!f;
+        }());
+    }
+    expect: {
+        console.log(function f() {
+            return f = 0, !!f;
+        }());
+    }
+    expect_stdout: "true"
+}
+
+func_def_3: {
+    options = {
+        cascade: true,
+        side_effects: true,
+    }
+    input: {
+        function f() {
+            function g() {}
+            return g = 0, !!g;
+        }
+        console.log(f());
+    }
+    expect: {
+        function f() {
+            function g() {}
+            return !!(g = 0);
+        }
+        console.log(f());
+    }
+    expect_stdout: "false"
+}
+
+func_def_4: {
+    options = {
+        cascade: true,
+        side_effects: true,
+    }
+    input: {
+        function f() {
+            function g() {
+                return g = 0, !!g;
+            }
+            return g();
+        }
+        console.log(f());
+    }
+    expect: {
+        function f() {
+            function g() {
+                return !!(g = 0);
+            }
+            return g();
+        }
+        console.log(f());
+    }
+    expect_stdout: "false"
+}
+
+func_def_5: {
+    options = {
+        cascade: true,
+        side_effects: true,
+    }
+    input: {
+        function f() {
+            return function g(){
+                return g = 0, !!g;
+            }();
+        }
+        console.log(f());
+    }
+    expect: {
+        function f() {
+            return function g(){
+                return g = 0, !!g;
+            }();
+        }
+        console.log(f());
+    }
+    expect_stdout: "true"
+}
diff --git a/test/compress/switch.js b/test/compress/switch.js
index 62e39cf7..5c12449c 100644
--- a/test/compress/switch.js
+++ b/test/compress/switch.js
@@ -258,3 +258,425 @@ keep_default: {
         }
     }
 }
+
+issue_1663: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        function f() {
+            switch (1) {
+              case 1:
+                b = a++;
+                return ++b;
+              default:
+                var b;
+            }
+        }
+        f();
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        function f() {
+            var b;
+            b = a++;
+            return ++b;
+        }
+        f();
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
+drop_case: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        switch (foo) {
+          case 'bar': baz(); break;
+          case 'moo':
+            break;
+        }
+    }
+    expect: {
+        switch (foo) {
+          case 'bar': baz();
+        }
+    }
+}
+
+keep_case: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        switch (foo) {
+          case 'bar': baz(); break;
+          case moo:
+            break;
+        }
+    }
+    expect: {
+        switch (foo) {
+          case 'bar': baz(); break;
+          case moo:
+        }
+    }
+}
+
+issue_376: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+    }
+    input: {
+        switch (true) {
+          case boolCondition:
+            console.log(1);
+            break;
+          case false:
+            console.log(2);
+            break;
+        }
+    }
+    expect: {
+        switch (true) {
+          case boolCondition:
+            console.log(1);
+        }
+    }
+}
+
+issue_441_1: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        switch (foo) {
+          case bar:
+            qux();
+            break;
+          case baz:
+            qux();
+            break;
+          default:
+            qux();
+            break;
+        }
+    }
+    expect: {
+        switch (foo) {
+          case bar:
+          case baz:
+          default:
+            qux();
+        }
+    }
+}
+
+issue_441_2: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        switch (foo) {
+          case bar:
+            // TODO: Fold into the case below
+            qux();
+            break;
+          case fall:
+          case baz:
+            qux();
+            break;
+          default:
+            qux();
+            break;
+        }
+    }
+    expect: {
+        switch (foo) {
+          case bar:
+            qux();
+            break;
+          case fall:
+          case baz:
+          default:
+            qux();
+        }
+    }
+}
+
+issue_1674: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+    }
+    input: {
+        switch (0) {
+          default:
+            console.log("FAIL");
+            break;
+          case 0:
+            console.log("PASS");
+            break;
+        }
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_1679: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        function f() {
+            switch (--b) {
+              default:
+              case !function x() {}:
+                break;
+              case b--:
+                switch (0) {
+                  default:
+                  case a--:
+                }
+                break;
+              case (a++):
+                break;
+            }
+        }
+        f();
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        function f() {
+            switch (--b) {
+              default:
+              case !function x() {}:
+                break;
+              case b--:
+                switch (0) {
+                  default:
+                  case a--:
+                }
+                break;
+              case (a++):
+            }
+        }
+        f();
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
+issue_1680_1: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+    }
+    input: {
+        function f(x) {
+            console.log(x);
+            return x + 1;
+        }
+        switch (2) {
+          case f(0):
+          case f(1):
+            f(2);
+          case 2:
+          case f(3):
+          case f(4):
+            f(5);
+        }
+    }
+    expect: {
+        function f(x) {
+            console.log(x);
+            return x + 1;
+        }
+        switch (2) {
+          case f(0):
+          case f(1):
+            f(2);
+          case 2:
+            f(5);
+        }
+    }
+    expect_stdout: [
+        "0",
+        "1",
+        "2",
+        "5",
+    ]
+}
+
+issue_1680_2: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        switch (b) {
+          case a--:
+            break;
+          case b:
+            var c;
+            break;
+          case a:
+            break;
+          case a--:
+            break;
+        }
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        switch (b) {
+          case a--:
+            break;
+          case b:
+            var c;
+            break;
+          case a:
+          case a--:
+        }
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
+issue_1690_1: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        switch (console.log("PASS")) {}
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+issue_1690_2: {
+    options = {
+        dead_code: false,
+    }
+    input: {
+        switch (console.log("PASS")) {}
+    }
+    expect: {
+        switch (console.log("PASS")) {}
+    }
+    expect_stdout: "PASS"
+}
+
+if_switch_typeof: {
+    options = {
+        conditionals: true,
+        dead_code: true,
+        side_effects: true,
+    }
+    input: {
+        if (a) switch(typeof b) {}
+    }
+    expect: {
+        a;
+    }
+}
+
+issue_1698: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        var a = 1;
+        !function() {
+            switch (a++) {}
+        }();
+        console.log(a);
+    }
+    expect: {
+        var a = 1;
+        !function() {
+            switch (a++) {}
+        }();
+        console.log(a);
+    }
+    expect_stdout: "2"
+}
+
+issue_1705_1: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = 0;
+        switch (a) {
+          default:
+            console.log("FAIL");
+          case 0:
+            break;
+        }
+    }
+    expect: {
+        var a = 0;
+        switch (a) {
+          default:
+            console.log("FAIL");
+          case 0:
+        }
+    }
+    expect_stdout: true
+}
+
+issue_1705_2: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 0;
+        switch (a) {
+          default:
+            console.log("FAIL");
+          case 0:
+            break;
+        }
+    }
+    expect: {
+    }
+    expect_stdout: true
+}
+
+issue_1705_3: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        switch (a) {
+          case 0:
+            break;
+          default:
+            break;
+        }
+    }
+    expect: {
+        a;
+    }
+    expect_stdout: true
+}
diff --git a/test/compress/transform.js b/test/compress/transform.js
index 1cc72c07..48aa605e 100644
--- a/test/compress/transform.js
+++ b/test/compress/transform.js
@@ -30,7 +30,6 @@ booleans_global_defs: {
     expect: {
         console.log(!0);
     }
-    expect_stdout: true
 }
 
 condition_evaluate: {
diff --git a/test/compress/typeof.js b/test/compress/typeof.js
index 7bf8e5e3..60f3d1d0 100644
--- a/test/compress/typeof.js
+++ b/test/compress/typeof.js
@@ -48,3 +48,15 @@ typeof_in_boolean_context: {
         foo();
     }
 }
+
+issue_1668: {
+    options = {
+        booleans: true,
+    }
+    input: {
+        if (typeof bar);
+    }
+    expect: {
+        if (!0);
+    }
+}
diff --git a/test/input/invalid/assign_1.js b/test/input/invalid/assign_1.js
new file mode 100644
index 00000000..6d09d132
--- /dev/null
+++ b/test/input/invalid/assign_1.js
@@ -0,0 +1 @@
+console.log(1 || 5--);
diff --git a/test/input/invalid/assign_2.js b/test/input/invalid/assign_2.js
new file mode 100644
index 00000000..197bdc90
--- /dev/null
+++ b/test/input/invalid/assign_2.js
@@ -0,0 +1 @@
+console.log(2 || (Math.random() /= 2));
diff --git a/test/input/invalid/assign_3.js b/test/input/invalid/assign_3.js
new file mode 100644
index 00000000..7c560e4b
--- /dev/null
+++ b/test/input/invalid/assign_3.js
@@ -0,0 +1 @@
+console.log(3 || ++this);
diff --git a/test/mocha/cli.js b/test/mocha/cli.js
index 2b44c901..b956309a 100644
--- a/test/mocha/cli.js
+++ b/test/mocha/cli.js
@@ -251,4 +251,59 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
+    it("Should support hyphen as shorthand", function(done) {
+       var command = uglifyjscmd + ' test/input/issue-1431/sample.js -m keep-fnames=true';
+
+       exec(command, function (err, stdout) {
+           if (err) throw err;
+
+           assert.strictEqual(stdout, "function f(r){return function(){function n(n){return n*n}return r(n)}}function g(n){return n(1)+n(2)}console.log(f(g)()==5);\n");
+           done();
+       });
+    });
+    it("Should throw syntax error (5--)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/assign_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/assign_1.js:1,18",
+               "console.log(1 || 5--);",
+               "                  ^",
+               "SyntaxError: Invalid use of -- operator"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (Math.random() /= 2)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/assign_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/assign_2.js:1,32",
+               "console.log(2 || (Math.random() /= 2));",
+               "                                ^",
+               "SyntaxError: Invalid assignment"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (++this)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/assign_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/assign_3.js:1,18",
+               "console.log(3 || ++this);",
+               "                  ^",
+               "SyntaxError: Invalid use of ++ operator"
+           ].join("\n"));
+           done();
+       });
+    });
 });
diff --git a/test/mocha/glob.js b/test/mocha/glob.js
index e291efc8..e9555a52 100644
--- a/test/mocha/glob.js
+++ b/test/mocha/glob.js
@@ -5,7 +5,7 @@ var path = require("path");
 describe("minify() with input file globs", function() {
     it("minify() with one input file glob string.", function() {
         var result = Uglify.minify("test/input/issue-1242/foo.*");
-        assert.strictEqual(result.code, 'function foo(o){var n=2*o;print("Foo:",n)}var print=console.log.bind(console);');
+        assert.strictEqual(result.code, 'function foo(o){print("Foo:",2*o)}var print=console.log.bind(console);');
     });
     it("minify() with an array of one input file glob.", function() {
         var result = Uglify.minify([
@@ -20,7 +20,7 @@ describe("minify() with input file globs", function() {
         ], {
             compress: { toplevel: true }
         });
-        assert.strictEqual(result.code, 'var print=console.log.bind(console),a=function(n){return 3*n}(3),b=function(n){return n/2}(12);print("qux",a,b),function(n){var o=2*n;print("Foo:",o)}(11);');
+        assert.strictEqual(result.code, 'var print=console.log.bind(console),a=function(n){return 3*n}(3),b=function(n){return n/2}(12);print("qux",a,b),function(n){print("Foo:",2*n)}(11);');
     });
     it("should throw with non-matching glob string", function() {
         var glob = "test/input/issue-1242/blah.*";
diff --git a/test/run-tests.js b/test/run-tests.js
index 09e70021..3d291416 100755
--- a/test/run-tests.js
+++ b/test/run-tests.js
@@ -105,6 +105,23 @@ function run_compress_tests() {
         function test_case(test) {
             log_test(test.name);
             U.base54.reset();
+            var output_options = test.beautify || {};
+            var expect;
+            if (test.expect) {
+                expect = make_code(as_toplevel(test.expect, test.mangle), output_options);
+            } else {
+                expect = test.expect_exact;
+            }
+            var input = as_toplevel(test.input, test.mangle);
+            var input_code = make_code(input, output_options);
+            var input_formatted = make_code(test.input, {
+                beautify: true,
+                quote_style: 3,
+                keep_quoted_props: true
+            });
+            if (test.mangle_props) {
+                input = U.mangle_properties(input, test.mangle_props);
+            }
             var options = U.defaults(test.options, {
                 warnings: false
             });
@@ -117,22 +134,6 @@ function run_compress_tests() {
                 if (!options.warnings) options.warnings = true;
             }
             var cmp = new U.Compressor(options, true);
-            var output_options = test.beautify || {};
-            var expect;
-            if (test.expect) {
-                expect = make_code(as_toplevel(test.expect, test.mangle), output_options);
-            } else {
-                expect = test.expect_exact;
-            }
-            var input = as_toplevel(test.input, test.mangle);
-            var input_code = make_code(test.input, {
-                beautify: true,
-                quote_style: 3,
-                keep_quoted_props: true
-            });
-            if (test.mangle_props) {
-                input = U.mangle_properties(input, test.mangle_props);
-            }
             var output = cmp.compress(input);
             output.figure_out_scope(test.mangle);
             if (test.mangle) {
@@ -142,7 +143,7 @@ function run_compress_tests() {
             output = make_code(output, output_options);
             if (expect != output) {
                 log("!!! failed\n---INPUT---\n{input}\n---OUTPUT---\n{output}\n---EXPECTED---\n{expected}\n\n", {
-                    input: input_code,
+                    input: input_formatted,
                     output: output,
                     expected: expect
                 });
@@ -155,7 +156,7 @@ function run_compress_tests() {
                     var reparsed_ast = U.parse(output);
                 } catch (ex) {
                     log("!!! Test matched expected result but cannot parse output\n---INPUT---\n{input}\n---OUTPUT---\n{output}\n--REPARSE ERROR--\n{error}\n\n", {
-                        input: input_code,
+                        input: input_formatted,
                         output: output,
                         error: ex.toString(),
                     });
@@ -174,7 +175,7 @@ function run_compress_tests() {
                     var actual_warnings = JSON.stringify(warnings_emitted);
                     if (expected_warnings != actual_warnings) {
                         log("!!! failed\n---INPUT---\n{input}\n---EXPECTED WARNINGS---\n{expected_warnings}\n---ACTUAL WARNINGS---\n{actual_warnings}\n\n", {
-                            input: input_code,
+                            input: input_formatted,
                             expected_warnings: expected_warnings,
                             actual_warnings: actual_warnings,
                         });
@@ -183,13 +184,13 @@ function run_compress_tests() {
                     }
                 }
                 if (test.expect_stdout) {
-                    var stdout = run_code(make_code(input, output_options));
+                    var stdout = run_code(input_code);
                     if (test.expect_stdout === true) {
                         test.expect_stdout = stdout;
                     }
                     if (!same_stdout(test.expect_stdout, stdout)) {
                         log("!!! Invalid input or expected stdout\n---INPUT---\n{input}\n---EXPECTED {expected_type}---\n{expected}\n---ACTUAL {actual_type}---\n{actual}\n\n", {
-                            input: input_code,
+                            input: input_formatted,
                             expected_type: typeof test.expect_stdout == "string" ? "STDOUT" : "ERROR",
                             expected: test.expect_stdout,
                             actual_type: typeof stdout == "string" ? "STDOUT" : "ERROR",
@@ -201,7 +202,7 @@ function run_compress_tests() {
                         stdout = run_code(output);
                         if (!same_stdout(test.expect_stdout, stdout)) {
                             log("!!! failed\n---INPUT---\n{input}\n---EXPECTED {expected_type}---\n{expected}\n---ACTUAL {actual_type}---\n{actual}\n\n", {
-                                input: input_code,
+                                input: input_formatted,
                                 expected_type: typeof test.expect_stdout == "string" ? "STDOUT" : "ERROR",
                                 expected: test.expect_stdout,
                                 actual_type: typeof stdout == "string" ? "STDOUT" : "ERROR",
diff --git a/test/ufuzz.js b/test/ufuzz.js
new file mode 100644
index 00000000..c1ac8f4c
--- /dev/null
+++ b/test/ufuzz.js
@@ -0,0 +1,477 @@
+// ufuzz.js
+// derived from https://github.com/qfox/uglyfuzzer by Peter van der Zee
+"use strict";
+
+// workaround for tty output truncation upon process.exit()
+[process.stdout, process.stderr].forEach(function(stream){
+    if (stream._handle && stream._handle.setBlocking)
+        stream._handle.setBlocking(true);
+});
+
+var vm = require("vm");
+var minify = require("..").minify;
+
+var MAX_GENERATED_FUNCTIONS_PER_RUN = 1;
+var MAX_GENERATION_RECURSION_DEPTH = 15;
+var INTERVAL_COUNT = 100;
+
+var VALUES = [
+  'true',
+  'false',
+  '22',
+  '0',
+  '-0', // 0/-0 !== 0
+  '23..toString()',
+  '24 .toString()',
+  '25. ',
+  '0x26.toString()',
+  '(-1)',
+  'NaN',
+  'undefined',
+  'Infinity',
+  'null',
+  '[]',
+  '[,0][1]', // an array with elisions... but this is always false
+  '([,0].length === 2)', // an array with elisions... this is always true
+  '({})', // wrapped the object causes too many syntax errors in statements
+  '"foo"',
+  '"bar"' ];
+
+var BINARY_OPS_NO_COMMA = [
+  ' + ', // spaces needed to disambiguate with ++ cases (could otherwise cause syntax errors)
+  ' - ',
+  '/',
+  '*',
+  '&',
+  '|',
+  '^',
+  '<<',
+  '>>',
+  '>>>',
+  '%',
+  '&&',
+  '||',
+  '^' ];
+
+var BINARY_OPS = [','].concat(BINARY_OPS_NO_COMMA);
+
+var ASSIGNMENTS = [
+  '=',
+  '=',
+  '=',
+  '=',
+  '=',
+  '=',
+
+  '==',
+  '!=',
+  '===',
+  '!==',
+  '+=',
+  '-=',
+  '*=',
+  '/=',
+  '&=',
+  '|=',
+  '^=',
+  '<<=',
+  '>>=',
+  '>>>=',
+  '%=' ];
+
+var UNARY_OPS = [
+  '--',
+  '++',
+  '~',
+  '!',
+  'void ',
+  'delete ', // should be safe, even `delete foo` and `delete f()` shouldn't crash
+  ' - ',
+  ' + ' ];
+
+var NO_COMMA = true;
+var MAYBE = true;
+var NESTED = true;
+var CAN_THROW = true;
+var CANNOT_THROW = false;
+var CAN_BREAK = true;
+var CAN_CONTINUE = true;
+
+var VAR_NAMES = [
+  'foo',
+  'bar',
+  'a',
+  'b',
+  'undefined', // fun!
+  'eval', // mmmm, ok, also fun!
+  'NaN', // mmmm, ok, also fun!
+  'Infinity', // the fun never ends!
+  'arguments', // this one is just creepy
+  'Math', // since Math is assumed to be a non-constructor/function it may trip certain cases
+  'let' ]; // maybe omit this, it's more a parser problem than minifier
+
+var TYPEOF_OUTCOMES = [
+  'undefined',
+  'string',
+  'number',
+  'object',
+  'boolean',
+  'special',
+  'unknown',
+  'symbol',
+  'crap' ];
+
+var FUNC_TOSTRING = [
+    "Function.prototype.toString = function() {",
+    "    var ids = [];",
+    "    return function() {",
+    "        var i = ids.indexOf(this);",
+    "        if (i < 0) {",
+    "            i = ids.length;",
+    "            ids.push(this);",
+    "        }",
+    '        return "[Function: __func_" + i + "__]";',
+    "    }",
+    "}();",
+    ""
+].join("\n");
+
+function run_code(code) {
+    var stdout = "";
+    var original_write = process.stdout.write;
+    process.stdout.write = function(chunk) {
+        stdout += chunk;
+    };
+    try {
+        new vm.Script(FUNC_TOSTRING + code).runInNewContext({
+            console: {
+                log: function() {
+                    return console.log.apply(console, [].map.call(arguments, function(arg) {
+                        return typeof arg == "function" ? "[Function]" : arg;
+                    }));
+                }
+            }
+        }, { timeout: 5000 });
+        return stdout;
+    } catch (ex) {
+        return ex;
+    } finally {
+        process.stdout.write = original_write;
+    }
+}
+
+function rng(max) {
+  return Math.floor(max * Math.random());
+}
+
+function createFunctionDecls(n, recurmax, nested) {
+  if (--recurmax < 0) { return ';'; }
+  var s = '';
+  while (n-- > 0) {
+    s += createFunctionDecl(recurmax, nested) + '\n';
+  }
+  return s;
+}
+
+var funcs = 0;
+function createFunctionDecl(recurmax, nested) {
+  if (--recurmax < 0) { return ';'; }
+  var func = funcs++;
+  var name = rng(5) > 0 ? 'f' + func : createVarName();
+  if (name === 'a' || name === 'b') name = 'f' + func; // quick hack to prevent assignment to func names of being called
+  if (!nested && name === 'undefined' || name === 'NaN' || name === 'Infinity') name = 'f' + func; // cant redefine these in global space
+  var s = '';
+  if (rng(5) === 1) {
+    // functions with functions. lower the recursion to prevent a mess.
+    s = 'function ' + name + '(){' + createFunctionDecls(rng(5) + 1, Math.ceil(recurmax / 2), NESTED) + '}\n';
+  } else {
+    // functions with statements
+    s = 'function ' + name + '(){' + createStatements(3, recurmax) + '}\n';
+  }
+
+  if (nested) s = '!' + nested; // avoid "function statements" (decl inside statements)
+  else s += name + '();'
+
+  return s;
+}
+
+function createStatements(n, recurmax, canThrow, canBreak, canContinue) {
+  if (--recurmax < 0) { return ';'; }
+  var s = '';
+  while (--n > 0) {
+    s += createStatement(recurmax, canThrow, canBreak, canContinue);
+  }
+  return s;
+}
+
+var loops = 0;
+function createStatement(recurmax, canThrow, canBreak, canContinue) {
+  var loop = ++loops;
+  if (--recurmax < 0) { return ';'; }
+  switch (rng(16)) {
+    case 0:
+      return '{' + createStatements(rng(5) + 1, recurmax, canThrow, canBreak, canContinue) + '}';
+    case 1:
+      return 'if (' + createExpression(recurmax) + ')' + createStatement(recurmax, canThrow, canBreak, canContinue) + (rng(2) === 1 ? ' else ' + createStatement(recurmax, canThrow, canBreak, canContinue) : '');
+    case 2:
+      return '{var brake' + loop + ' = 5; do {' + createStatement(recurmax, canThrow, CAN_BREAK, CAN_CONTINUE) + '} while ((' + createExpression(recurmax) + ') && --brake' + loop + ' > 0);}';
+    case 3:
+      return '{var brake' + loop + ' = 5; while ((' + createExpression(recurmax) + ') && --brake' + loop + ' > 0)' + createStatement(recurmax, canThrow, CAN_BREAK, CAN_CONTINUE) + '}';
+    case 4:
+      return 'for (var brake' + loop + ' = 5; (' + createExpression(recurmax) + ') && brake' + loop + ' > 0; --brake' + loop + ')' + createStatement(recurmax, canThrow, CAN_BREAK, CAN_CONTINUE);
+    case 5:
+      return ';';
+    case 6:
+      return createExpression(recurmax) + ';';
+    case 7:
+      // note: case args are actual expressions
+      // note: default does not _need_ to be last
+      return 'switch (' + createExpression(recurmax) + ') { ' + createSwitchParts(recurmax, 4) + '}';
+    case 8:
+      return 'var ' + createVarName() + ';';
+    case 9:
+      // initializer can only have one expression
+      return 'var ' + createVarName() + ' = ' + createExpression(recurmax, NO_COMMA) + ';';
+    case 10:
+      // initializer can only have one expression
+      return 'var ' + createVarName() + ' = ' + createExpression(recurmax, NO_COMMA) + ', ' + createVarName() + ' = ' + createExpression(recurmax, NO_COMMA) + ';';
+    case 11:
+      if (canBreak && rng(5) === 0) return 'break;';
+      if (canContinue && rng(5) === 0) return 'continue;';
+      return 'return;';
+    case 12:
+      // must wrap in curlies to prevent orphaned `else` statement
+      if (canThrow && rng(5) === 0) return '{ throw ' + createExpression(recurmax) + '}';
+      return '{ return ' + createExpression(recurmax) + '}';
+    case 13:
+      // this is actually more like a parser test, but perhaps it hits some dead code elimination traps
+      // must wrap in curlies to prevent orphaned `else` statement
+      if (canThrow && rng(5) === 0) return '{ throw\n' + createExpression(recurmax) + '}';
+      return '{ return\n' + createExpression(recurmax) + '}';
+    case 14:
+      // "In non-strict mode code, functions can only be declared at top level, inside a block, or ..."
+      // (dont both with func decls in `if`; it's only a parser thing because you cant call them without a block)
+      return '{' + createFunctionDecl(recurmax, NESTED) + '}';
+    case 15:
+      return ';';
+      // catch var could cause some problems
+      // note: the "blocks" are syntactically mandatory for try/catch/finally
+      var s = 'try {' + createStatement(recurmax, CAN_THROW, canBreak, canContinue) + ' }';
+      var n = rng(3); // 0=only catch, 1=only finally, 2=catch+finally
+      if (n !== 1) s += ' catch (' + createVarName() + ') { ' + createStatements(3, recurmax, canBreak, canContinue) + ' }';
+      if (n !== 0) s += ' finally { ' + createStatements(3, recurmax, canBreak, canContinue) + ' }';
+      return s;
+  }
+}
+
+function createSwitchParts(recurmax, n) {
+  var hadDefault = false;
+  var s = '';
+  while (n-- > 0) {
+    hadDefault = n > 0;
+    if (hadDefault || rng(4) > 0) {
+      s += '' +
+        'case ' + createExpression(recurmax) + ':\n' +
+            createStatements(rng(3) + 1, recurmax, CANNOT_THROW, CAN_BREAK) +
+            '\n' +
+            (rng(10) > 0 ? ' break;' : '/* fall-through */') +
+        '\n';
+    } else {
+      hadDefault = true;
+      s += '' +
+        'default:\n' +
+            createStatements(rng(3) + 1, recurmax, CANNOT_THROW, CAN_BREAK) +
+        '\n';
+    }
+  }
+  return s;
+}
+
+function createExpression(recurmax, noComma) {
+  if (--recurmax < 0) {
+    return createValue(); // note: should return a simple non-recursing expression value!
+  }
+  switch (rng(12)) {
+    case 0:
+      return '(' + createUnaryOp() + (rng(2) === 1 ? 'a' : 'b') + ')';
+    case 1:
+      return '(a' + (rng(2) == 1 ? '++' : '--') + ')';
+    case 2:
+      return '(b ' + createAssignment() + ' a)';
+    case 3:
+      return '(' + rng(2) + ' === 1 ? a : b)';
+    case 4:
+      return createExpression(recurmax, noComma) + createBinaryOp(noComma) + createExpression(recurmax, noComma);
+    case 5:
+      return createValue();
+    case 6:
+      return '(' + createExpression(recurmax) + ')';
+    case 7:
+      return createExpression(recurmax, noComma) + '?(' + createExpression(recurmax) + '):(' + createExpression(recurmax) + ')';
+    case 8:
+      switch(rng(4)) {
+        case 0:
+          return '(function ' + createVarName(MAYBE) + '(){' + createStatements(rng(5) + 1, recurmax) + '})()';
+        case 1:
+          return '+function ' + createVarName(MAYBE) + '(){' + createStatements(rng(5) + 1, recurmax) + '}';
+        case 2:
+          return '!function ' + createVarName(MAYBE) + '(){' + createStatements(rng(5) + 1, recurmax) + '}';
+        case 3:
+          return 'void function ' + createVarName(MAYBE) + '(){' + createStatements(rng(5) + 1, recurmax) + '}';
+        default:
+          return 'void function ' + createVarName(MAYBE) + '(){' + createStatements(rng(5) + 1, recurmax) + '}';
+      }
+    case 9:
+      return createTypeofExpr(recurmax);
+    case 10:
+      // you could statically infer that this is just `Math`, regardless of the other expression
+      // I don't think Uglify does this at this time...
+      return ''+
+        'new function(){ \n' +
+        (rng(2) === 1 ? createExpression(recurmax) + '\n' : '') +
+        'return Math;\n' +
+      '}';
+    case 11:
+      // more like a parser test but perhaps comment nodes mess up the analysis?
+      switch (rng(5)) {
+        case 0:
+          return '(a/* ignore */++)';
+        case 1:
+          return '(b/* ignore */--)';
+        case 2:
+          return '(++/* ignore */a)';
+        case 3:
+          return '(--/* ignore */b)';
+        case 4:
+          // only groups that wrap a single variable return a "Reference", so this is still valid.
+          // may just be a parser edge case that is invisible to uglify...
+          return '(--(b))';
+        default:
+          return '(--/* ignore */b)';
+      }
+  }
+}
+
+function createTypeofExpr(recurmax) {
+  if (--recurmax < 0) {
+    return 'typeof undefined === "undefined"';
+  }
+
+  switch (rng(5)) {
+    case 0:
+      return '(typeof ' + createVarName() + ' === "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
+    case 1:
+      return '(typeof ' + createVarName() + ' !== "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
+    case 2:
+      return '(typeof ' + createVarName() + ' == "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
+    case 3:
+      return '(typeof ' + createVarName() + ' != "' + TYPEOF_OUTCOMES[rng(TYPEOF_OUTCOMES.length)] + '")';
+    case 4:
+      return '(typeof ' + createVarName() + ')';
+  }
+}
+
+function createValue() {
+  return VALUES[rng(VALUES.length)];
+}
+
+function createBinaryOp(noComma) {
+  if (noComma) return BINARY_OPS_NO_COMMA[rng(BINARY_OPS_NO_COMMA.length)];
+  return BINARY_OPS[rng(BINARY_OPS.length)];
+}
+
+function createAssignment() {
+  return ASSIGNMENTS[rng(ASSIGNMENTS.length)];
+}
+
+function createUnaryOp() {
+  return UNARY_OPS[rng(UNARY_OPS.length)];
+}
+
+function createVarName(maybe) {
+  if (!maybe || rng(2) === 1) {
+    return VAR_NAMES[rng(VAR_NAMES.length)] + (rng(5) > 0 ? ++loops : '');
+  }
+  return '';
+}
+
+function log(ok) {
+    console.log("//=============================================================");
+    if (!ok) console.log("// !!!!!! Failed...");
+    console.log("// original code");
+    console.log("//");
+    console.log(original_code);
+    console.log();
+    console.log();
+    console.log("//-------------------------------------------------------------");
+    console.log("// original code (beautify'd)");
+    console.log("//");
+    console.log(beautify_code);
+    console.log();
+    console.log();
+    console.log("//-------------------------------------------------------------");
+    console.log("// uglified code");
+    console.log("//");
+    console.log(uglify_code);
+    console.log();
+    console.log();
+    console.log("original result:");
+    console.log(original_result);
+    console.log("beautified result:");
+    console.log(beautify_result);
+    console.log("uglified result:");
+    console.log(uglify_result);
+    if (!ok) console.log("!!!!!! Failed...");
+}
+
+var num_iterations = +process.argv[2] || 1/0;
+var verbose = process.argv[3] === 'v' || process.argv[2] === 'v';
+var verbose_interval = process.argv[3] === 'V' || process.argv[2] === 'V';
+for (var round = 0; round < num_iterations; round++) {
+    var parse_error = false;
+    process.stdout.write(round + " of " + num_iterations + "\r");
+    var original_code = [
+        "var a = 100, b = 10;",
+        createFunctionDecls(rng(MAX_GENERATED_FUNCTIONS_PER_RUN) + 1, MAX_GENERATION_RECURSION_DEPTH),
+        "console.log(a, b);"
+    ].join("\n");
+    var original_result = run_code(original_code);
+
+    try {
+        var beautify_code = minify(original_code, {
+            fromString: true,
+            mangle: false,
+            compress: false,
+            output: {
+                beautify: true,
+                bracketize: true,
+            },
+        }).code;
+    } catch(e) {
+        parse_error = 1;
+    }
+    var beautify_result = run_code(beautify_code);
+
+    try {
+      var uglify_code = minify(beautify_code, {
+          fromString: true,
+          mangle: true,
+          compress: {
+              passes: 3,
+          },
+          output: {
+              //beautify: true,
+              //bracketize: true,
+          },
+      }).code;
+    } catch(e) {
+        parse_error = 2;
+    }
+    var uglify_result = run_code(uglify_code);
+
+    var ok = !parse_error && original_result == beautify_result && original_result == uglify_result;
+    if (verbose || (verbose_interval && !(round % INTERVAL_COUNT)) || !ok) log(ok);
+    if (parse_error === 1) console.log('Parse error while beautifying');
+    if (parse_error === 2) console.log('Parse error while uglifying');
+    if (!ok) break;
+}