v3.15.5

fixes #5436

README.md

@@ -1373,3 +1373,19 @@ To allow for better optimizations, the compiler makes various assumptions:
   // TypeError: const 'a' has already been declared
   ```
   UglifyJS may modify the input which in turn may suppress those errors.
+- Later versions of Chrome and Node.js will give incorrect results with the
+  following:
+  ```javascript
+  try {
+      class A {
+          static 42;
+          static get 42() {}
+      }
+      console.log("PASS");
+  } catch (e) {
+      console.log("FAIL");
+  }
+  // Expected: "PASS"
+  // Actual:   "FAIL"
+  ```
+  UglifyJS may modify the input which in turn may suppress those errors.

lib/ast.js

@@ -851,6 +851,9 @@ var AST_DefClass = DEFNODE("DefClass", null, {
     $propdoc: {
         name: "[AST_SymbolDefClass] the name of this class",
     },
+    resolve: function(def_class) {
+        return def_class ? this : this.parent_scope.resolve();
+    },
     _validate: function() {
         if (!(this.name instanceof AST_SymbolDefClass)) throw new Error("name must be AST_SymbolDefClass");
     },

lib/compress.js

@@ -649,7 +649,7 @@ Compressor.prototype.compress = function(node) {
             }
             if (!HOP(tw.safe_ids, def.id)) {
                 if (!safe) return false;
-                if (safe.read) {
+                if (safe.read || tw.in_loop) {
                     var scope = tw.find_parent(AST_BlockScope);
                     if (scope instanceof AST_Class) return false;
                     if (def.scope.resolve() !== scope.resolve()) return false;
@@ -751,6 +751,34 @@ Compressor.prototype.compress = function(node) {
             });
         }
 
+        function make_fixed(save, fn) {
+            var prev_save, prev_value;
+            return function() {
+                var current = save();
+                if (prev_save !== current) {
+                    prev_save = current;
+                    prev_value = fn(current);
+                }
+                return prev_value;
+            };
+        }
+
+        function make_fixed_default(compressor, node, save) {
+            var prev_save, prev_seq;
+            return function() {
+                var current = save();
+                var ev;
+                if (!is_undefined(current, compressor) && (ev = fuzzy_eval(compressor, current, true)) !== undefined) {
+                    return ev instanceof AST_Node ? node : current;
+                }
+                if (prev_save !== current) {
+                    prev_save = current;
+                    prev_seq = make_sequence(node, [ current, node.value ]);
+                }
+                return prev_seq;
+            };
+        }
+
         function scan_declaration(tw, compressor, lhs, fixed, visit) {
             var scanner = new TreeWalker(function(node) {
                 if (node instanceof AST_DefaultValue) {
@@ -759,15 +787,7 @@ Compressor.prototype.compress = function(node) {
                     node.value.walk(tw);
                     pop(tw);
                     var save = fixed;
-                    if (save) fixed = function() {
-                        var value = save();
-                        var ev;
-                        if (is_undefined(value, compressor)
-                            || (ev = fuzzy_eval(compressor, value, true)) === undefined) {
-                            return make_sequence(node, [ value, node.value ]);
-                        }
-                        return ev instanceof AST_Node ? node : value;
-                    };
+                    if (save) fixed = make_fixed_default(compressor, node, save);
                     node.name.walk(scanner);
                     fixed = save;
                     return true;
@@ -777,18 +797,17 @@ Compressor.prototype.compress = function(node) {
                     var save = fixed;
                     node.elements.forEach(function(node, index) {
                         if (node instanceof AST_Hole) return reset_flags(node);
-                        if (save) fixed = function() {
+                        if (save) fixed = make_fixed(save, function(value) {
                             return make_node(AST_Sub, node, {
-                                expression: save(),
+                                expression: value,
                                 property: make_node(AST_Number, node, { value: index }),
                             });
-                        };
+                        });
                         node.walk(scanner);
                     });
                     if (node.rest) {
                         var fixed_node;
-                        if (save) fixed = compressor.option("rests") && function() {
-                            var value = save();
+                        if (save) fixed = compressor.option("rests") && make_fixed(save, function(value) {
                             if (!(value instanceof AST_Array)) return node;
                             for (var i = 0, len = node.elements.length; i < len; i++) {
                                 if (value.elements[i] instanceof AST_Spread) return node;
@@ -796,7 +815,7 @@ Compressor.prototype.compress = function(node) {
                             if (!fixed_node) fixed_node = make_node(AST_Array, node);
                             fixed_node.elements = value.elements.slice(len);
                             return fixed_node;
-                        };
+                        });
                         node.rest.walk(scanner);
                     }
                     fixed = save;
@@ -812,7 +831,7 @@ Compressor.prototype.compress = function(node) {
                             node.key.walk(tw);
                             pop(tw);
                         }
-                        if (save) fixed = function() {
+                        if (save) fixed = make_fixed(save, function(value) {
                             var key = node.key;
                             var type = AST_Sub;
                             if (typeof key == "string") {
@@ -823,10 +842,10 @@ Compressor.prototype.compress = function(node) {
                                 }
                             }
                             return make_node(type, node, {
-                                expression: save(),
-                                property: key
+                                expression: value,
+                                property: key,
                             });
-                        };
+                        });
                         node.value.walk(scanner);
                     });
                     if (node.rest) {
@@ -2040,13 +2059,17 @@ Compressor.prototype.compress = function(node) {
                     if (is_lhs(node, parent)) {
                         if (value_def && !hit_rhs) assign_used = true;
                         return node;
-                    } else if (value_def) {
+                    }
+                    if (!hit_rhs && verify_ref && node.fixed !== lhs.fixed) {
+                        abort = true;
+                        return node;
+                    }
+                    if (value_def) {
                         if (stop_if_hit && assign_pos == 0) assign_pos = remaining - replaced;
                         if (!hit_rhs) replaced++;
                         return node;
-                    } else {
-                        replaced++;
                     }
+                    replaced++;
                     changed = abort = true;
                     AST_Node.info("Collapsing {node} [{file}:{line},{col}]", {
                         node: node,
@@ -2221,6 +2244,7 @@ Compressor.prototype.compress = function(node) {
                     var candidate = hit_stack[hit_stack.length - 1];
                     var assign_pos = -1;
                     var assign_used = false;
+                    var verify_ref = false;
                     var remaining;
                     var value_def = null;
                     var stop_after = null;
@@ -2248,8 +2272,11 @@ Compressor.prototype.compress = function(node) {
                     var lvalues = get_lvalues(candidate);
                     var lhs_local = is_lhs_local(lhs);
                     var rhs_value = get_rvalue(candidate);
-                    var rvalue = !compound && rhs_value instanceof AST_Sequence ? rhs_value.tail_node() : rhs_value;
-                    if (!side_effects) side_effects = value_has_side_effects();
+                    var rvalue = rhs_value;
+                    if (!side_effects) {
+                        if (!compound && rvalue instanceof AST_Sequence) rvalue = rvalue.tail_node();
+                        side_effects = value_has_side_effects();
+                    }
                     var check_destructured = in_try || !lhs_local ? function(node) {
                         return node instanceof AST_Destructured;
                     } : return_false;
@@ -2936,6 +2963,7 @@ Compressor.prototype.compress = function(node) {
                         if (matches < remaining) {
                             remaining = matches;
                             assign_pos = 0;
+                            verify_ref = true;
                         }
                     }
                     if (expr.operator == "=") mangleable_var(expr.right);
@@ -3163,47 +3191,42 @@ Compressor.prototype.compress = function(node) {
                     return;
                 }
                 var end = hit_stack.length - 1;
-                if (hit_stack[end - 1].body === hit_stack[end]) end--;
+                var last = hit_stack[end];
+                if (last instanceof AST_VarDef || hit_stack[end - 1].body === last) end--;
                 var tt = new TreeTransformer(function(node, descend, in_list) {
                     if (hit) return node;
                     if (node !== hit_stack[hit_index]) return node;
                     hit_index++;
                     if (hit_index <= end) return handle_custom_scan_order(node, tt);
                     hit = true;
-                    if (node instanceof AST_VarDef) {
-                        declare_only.set(node.name.name, (declare_only.get(node.name.name) || 0) + 1);
+                    if (node instanceof AST_Definitions) {
+                        declare_only.set(last.name.name, (declare_only.get(last.name.name) || 0) + 1);
                         if (value_def) value_def.replaced++;
-                        node = node.clone();
-                        node.value = null;
-                        return value ? List.splice([ value, node ]) : node;
+                        var defns = node.definitions;
+                        var index = defns.indexOf(last);
+                        var defn = last.clone();
+                        defn.value = null;
+                        if (!value) {
+                            node.definitions[index] = defn;
+                            return node;
+                        }
+                        var body = [ make_node(AST_SimpleStatement, value, { body: value }) ];
+                        if (index > 0) {
+                            var head = node.clone();
+                            head.definitions = defns.slice(0, index);
+                            body.unshift(head);
+                            node = node.clone();
+                            node.definitions = defns.slice(index);
+                        }
+                        body.push(node);
+                        node.definitions[0] = defn;
+                        return in_list ? List.splice(body) : make_node(AST_BlockStatement, node, { body: body });
                     }
                     if (!value) return in_list ? List.skip : null;
                     return is_statement(node) ? make_node(AST_SimpleStatement, value, { body: value }) : value;
                 }, function(node, in_list) {
-                    if (node instanceof AST_Definitions) {
-                        var body = [], defns = node.definitions;
-                        for (var index = 0, pos = 0; index < defns.length; index++) {
-                            var defn = defns[index];
-                            if (defn instanceof AST_VarDef) continue;
-                            flush();
-                            pos = index + 1;
-                            body.push(make_node(AST_SimpleStatement, defn, { body: defn }));
-                        }
-                        if (pos == 0) return;
-                        flush();
-                        if (body.length == 1) return body[0];
-                        return in_list ? List.splice(body) : make_node(AST_BlockStatement, node, { body: body });
-                    }
                     if (node instanceof AST_For) return patch_for_init(node, in_list);
-                    return patch_sequence(node, this);
-
-                    function flush() {
-                        if (pos < index) {
-                            var cropped = node.clone();
-                            cropped.definitions = defns.slice(pos, index);
-                            body.push(cropped);
-                        }
-                    }
+                    return patch_sequence(node, tt);
                 });
                 abort = false;
                 hit = false;
@@ -3249,9 +3272,13 @@ Compressor.prototype.compress = function(node) {
                 }
                 var def = lhs.definition();
                 if (def.references.length - def.replaced == referenced) return true;
-                return def.fixed && lhs.fixed && def.references.filter(function(ref) {
+                if (!def.fixed) return false;
+                if (!lhs.fixed) return false;
+                if (def.references.filter(function(ref) {
                     return ref.fixed === lhs.fixed;
-                }).length == referenced;
+                }).length != referenced) return false;
+                verify_ref = true;
+                return true;
             }
 
             function symbol_in_lvalues(sym, parent) {
@@ -3269,7 +3296,7 @@ Compressor.prototype.compress = function(node) {
                 if (def.scope.resolve() !== scope) return true;
                 if (modify_toplevel && compressor.exposed(def)) return true;
                 return !all(def.references, function(ref) {
-                    return ref.scope.resolve() === scope;
+                    return ref.scope.resolve(true) === scope;
                 });
             }
 
@@ -4767,6 +4794,7 @@ Compressor.prototype.compress = function(node) {
         });
         var scan_modified = new TreeWalker(function(node) {
             if (node instanceof AST_Assign) modified(node.left);
+            if (node instanceof AST_ForEnumeration) modified(node.init);
             if (node instanceof AST_Unary && UNARY_POSTFIX[node.operator]) modified(node.expression);
         });
         function modified(node) {
@@ -5425,7 +5453,6 @@ Compressor.prototype.compress = function(node) {
                 return !(prop instanceof AST_ObjectGetter || prop instanceof AST_Spread);
             });
         });
-        def(AST_ObjectIdentity, return_true);
         def(AST_Sequence, function() {
             return this.tail_node().safe_to_spread();
         });
@@ -6054,18 +6081,15 @@ Compressor.prototype.compress = function(node) {
             }
             if (node instanceof AST_Call) {
                 var exp = node.expression;
-                var tail = exp.tail_node();
-                if (!(tail instanceof AST_LambdaExpression)) {
+                if (exp instanceof AST_LambdaExpression) {
+                    node.args.forEach(function(arg) {
+                        arg.walk(tw);
+                    });
+                    exp.walk(tw);
+                } else {
                     descend();
-                    return mark_expression(exp);
+                    mark_expression(exp);
                 }
-                if (exp !== tail) exp.expressions.slice(0, -1).forEach(function(node) {
-                    node.walk(tw);
-                });
-                node.args.forEach(function(arg) {
-                    arg.walk(tw);
-                });
-                tail.walk(tw);
                 return true;
             }
             if (node instanceof AST_Class) {
@@ -6078,9 +6102,10 @@ Compressor.prototype.compress = function(node) {
                     if (prop.static) {
                         prop.value.walk(tw);
                     } else {
-                        push(tw);
+                        push();
+                        segment.block = node;
                         prop.value.walk(tw);
-                        pop(tw);
+                        pop();
                     }
                 });
                 return true;
@@ -6145,6 +6170,8 @@ Compressor.prototype.compress = function(node) {
                 if (node === self) root = segment;
                 if (node instanceof AST_Lambda) {
                     if (node.name) references[node.name.definition().id] = false;
+                    var parent = tw.parent();
+                    var in_iife = parent && parent.TYPE == "Call" && parent.expression === node;
                     var marker = node.uses_arguments && !tw.has_directive("use strict") ? function(node) {
                         if (node instanceof AST_SymbolFunarg) references[node.definition().id] = false;
                     } : function(node) {
@@ -6160,11 +6187,13 @@ Compressor.prototype.compress = function(node) {
                             || node.parent_scope.find_variable(ref.name) === def)) {
                             references[def.id] = false;
                             references[ldef.id] = false;
-                        } else {
+                        } else if (in_iife) {
                             var save = segment;
                             pop();
                             mark(ref, true);
                             segment = save;
+                        } else {
+                            mark(ref, true);
                         }
                         return true;
                     });
@@ -6187,7 +6216,8 @@ Compressor.prototype.compress = function(node) {
                 } else {
                     descend();
                 }
-                return mark_expression(exp);
+                mark_expression(exp);
+                return true;
             }
             if (node instanceof AST_Switch) {
                 node.expression.walk(tw);
@@ -6219,9 +6249,7 @@ Compressor.prototype.compress = function(node) {
             if (node instanceof AST_Try) {
                 var save_try = in_try;
                 in_try = node;
-                var save = segment;
                 walk_body(node, tw);
-                segment = save;
                 if (node.bcatch) {
                     if (node.bcatch.argname) node.bcatch.argname.mark_symbol(function(node) {
                         if (node instanceof AST_SymbolCatch) {
@@ -6239,7 +6267,6 @@ Compressor.prototype.compress = function(node) {
                     }
                 }
                 in_try = save_try;
-                segment = save;
                 if (node.bfinally) node.bfinally.walk(tw);
                 return true;
             }
@@ -6289,11 +6316,9 @@ Compressor.prototype.compress = function(node) {
             }
 
             function mark_expression(exp) {
-                if (compressor.option("ie")) {
-                    var sym = root_expr(exp);
-                    if (sym instanceof AST_SymbolRef) sym.walk(tw);
-                }
-                return true;
+                if (!compressor.option("ie")) return;
+                var sym = root_expr(exp);
+                if (sym instanceof AST_SymbolRef) sym.walk(tw);
             }
 
             function walk_cond(condition, consequent, alternative) {
@@ -6847,7 +6872,14 @@ Compressor.prototype.compress = function(node) {
                     });
                 }
             }
-            if (node instanceof AST_Call) calls_to_drop_args.push(node);
+            if (node instanceof AST_Call) {
+                calls_to_drop_args.push(node);
+                node.args = node.args.map(function(arg) {
+                    return arg.transform(tt);
+                });
+                node.expression = node.expression.transform(tt);
+                return node;
+            }
             if (scope !== self) return;
             if (drop_funcs && node !== self && node instanceof AST_DefClass) {
                 var def = node.name.definition();
@@ -7114,6 +7146,7 @@ Compressor.prototype.compress = function(node) {
                         if (def.orig.length > 1) return null;
                         if (def.assignments > 0) return false;
                         if (def.name == name) return def;
+                        if (compressor.option("keep_fnames")) return false;
                         var forbidden;
                         switch (name) {
                           case "await":
@@ -7818,7 +7851,7 @@ Compressor.prototype.compress = function(node) {
         var consts = new Dictionary();
         var dirs = [];
         var hoisted = [];
-        var vars = new Dictionary(), vars_found = 0;
+        var vars = new Dictionary();
         var tt = new TreeTransformer(function(node, descend, in_list) {
             if (node === self) return;
             if (node instanceof AST_Directive) {
@@ -7846,7 +7879,6 @@ Compressor.prototype.compress = function(node) {
                 })) return node;
                 node.definitions.forEach(function(defn) {
                     vars.set(defn.name.name, defn);
-                    ++vars_found;
                 });
                 var seq = node.to_assignments();
                 if (p instanceof AST_ForEnumeration && p.init === node) {
@@ -7865,7 +7897,7 @@ Compressor.prototype.compress = function(node) {
             }
         });
         self.transform(tt);
-        if (vars_found > 0) {
+        if (vars.size() > 0) {
             // collect only vars which don't show up in self's arguments list
             var defns = [];
             if (self instanceof AST_Lambda) self.each_argname(function(argname) {
@@ -9633,8 +9665,16 @@ Compressor.prototype.compress = function(node) {
                 fixed.escaped = def.escaped;
                 name.fixed = fixed;
                 def.references.forEach(function(ref) {
-                    var assigns = ref.fixed && ref.fixed.assigns;
-                    if (assigns && assigns[0] === defn) assigns[0] = assign;
+                    if (!ref.fixed) return;
+                    var assigns = ref.fixed.assigns;
+                    if (!assigns) return;
+                    if (assigns[0] !== defn) return;
+                    if (assigns.length > 1 || ref.fixed.to_binary || ref.fixed.to_prefix) {
+                        assigns[0] = assign;
+                    } else {
+                        ref.fixed = fixed;
+                        if (def.fixed === ref.fixed) def.fixed = fixed;
+                    }
                 });
                 def.references.push(name);
             }
@@ -11100,9 +11140,15 @@ Compressor.prototype.compress = function(node) {
                 && assign instanceof AST_Assign
                 && assign.operator == "="
                 && self.left.equivalent_to(assign.left)) {
-                self.right = assign.right;
-                assign.right = self;
-                return assign;
+                return make_node(AST_Assign, self, {
+                    operator: "=",
+                    left: assign.left,
+                    right: make_node(AST_Binary, self, {
+                        operator: self.operator,
+                        left: self.left,
+                        right: assign.right,
+                    }),
+                }).optimize(compressor);
             }
         }
         if (compressor.option("comparisons")) switch (self.operator) {
@@ -12901,43 +12947,44 @@ Compressor.prototype.compress = function(node) {
     AST_PropAccess.DEFMETHOD("flatten_object", function(key, compressor) {
         if (!compressor.option("properties")) return;
         if (key === "__proto__") return;
-        var expr = this.expression;
-        if (expr instanceof AST_Object) {
-            var props = expr.properties;
-            for (var i = props.length; --i >= 0;) {
-                var prop = props[i];
-                if (prop.key !== key) continue;
-                if (!all(props, can_hoist_property)) return;
-                if (!safe_to_flatten(prop.value, compressor)) return;
-                var scope, values = [];
-                for (var j = 0; j < props.length; j++) {
-                    var value = props[j].value;
-                    if (props[j] instanceof AST_ObjectMethod) {
-                        var arrow = !(value.uses_arguments || is_generator(value) || value.contains_this());
-                        if (arrow) {
-                            if (!scope) scope = compressor.find_parent(AST_Scope);
-                            var avoid = avoid_await_yield(scope);
-                            value.each_argname(function(argname) {
-                                if (avoid[argname.name]) arrow = false;
-                            });
-                        }
-                        var ctor;
-                        if (arrow) {
-                            ctor = is_async(value) ? AST_AsyncArrow : AST_Arrow;
-                        } else if (i === j && !(compressor.parent() instanceof AST_Call)) {
-                            return;
-                        } else {
-                            ctor = value.CTOR;
-                        }
-                        value = make_node(ctor, value, value);
+        var self = this;
+        var expr = self.expression;
+        if (!(expr instanceof AST_Object)) return;
+        var props = expr.properties;
+        for (var i = props.length; --i >= 0;) {
+            var prop = props[i];
+            if (prop.key !== key) continue;
+            if (!all(props, can_hoist_property)) return;
+            if (!safe_to_flatten(prop.value, compressor)) return;
+            var call, scope, values = [];
+            for (var j = 0; j < props.length; j++) {
+                var value = props[j].value;
+                if (props[j] instanceof AST_ObjectMethod) {
+                    var arrow = !(value.uses_arguments || is_generator(value) || value.contains_this());
+                    if (arrow) {
+                        if (!scope) scope = compressor.find_parent(AST_Scope);
+                        var avoid = avoid_await_yield(scope);
+                        value.each_argname(function(argname) {
+                            if (avoid[argname.name]) arrow = false;
+                        });
                     }
-                    values.push(value);
+                    var ctor;
+                    if (arrow) {
+                        ctor = is_async(value) ? AST_AsyncArrow : AST_Arrow;
+                    } else if (i != j
+                        || (call = compressor.parent()) instanceof AST_Call && call.expression === self) {
+                        ctor = value.CTOR;
+                    } else {
+                        return;
+                    }
+                    value = make_node(ctor, value, value);
                 }
-                return make_node(AST_Sub, this, {
-                    expression: make_node(AST_Array, expr, { elements: values }),
-                    property: make_node(AST_Number, this, { value: i }),
-                });
+                values.push(value);
             }
+            return make_node(AST_Sub, self, {
+                expression: make_node(AST_Array, expr, { elements: values }),
+                property: make_node(AST_Number, self, { value: i }),
+            });
         }
     });
 
@@ -13134,6 +13181,19 @@ Compressor.prototype.compress = function(node) {
         return found;
     }
 
+    function insert_assign(def, assign) {
+        var visited = [];
+        def.references.forEach(function(ref) {
+            var fixed = ref.fixed;
+            if (!fixed || !push_uniq(visited, fixed)) return;
+            if (fixed.assigns) {
+                fixed.assigns.unshift(assign);
+            } else {
+                fixed.assigns = [ assign ];
+            }
+        });
+    }
+
     function init_ref(compressor, name) {
         var sym = make_node(AST_SymbolRef, name, name);
         var assign = make_node(AST_Assign, name, {
@@ -13147,16 +13207,7 @@ Compressor.prototype.compress = function(node) {
                 return assign.right;
             };
             sym.fixed.assigns = [ assign ];
-            var visited = [];
-            def.references.forEach(function(ref) {
-                var fixed = ref.fixed;
-                if (!fixed || !push_uniq(visited, fixed)) return;
-                if (fixed.assigns) {
-                    fixed.assigns.unshift(assign);
-                } else {
-                    fixed.assigns = [ assign ];
-                }
-            });
+            insert_assign(def, assign);
         }
         def.assignments++;
         def.references.push(sym);
@@ -13260,6 +13311,7 @@ Compressor.prototype.compress = function(node) {
             if (fn.body[0] instanceof AST_Directive) return;
             if (fn.contains_this()) return;
             if (!scope) scope = find_scope(compressor);
+            if (in_async_generator(scope)) return;
             var defined = new Dictionary();
             defined.set("NaN", true);
             while (!(scope instanceof AST_Scope)) {
@@ -13334,7 +13386,7 @@ Compressor.prototype.compress = function(node) {
             });
             var body = [];
             fn.variables.each(function(def, name) {
-                if (name == "arguments") return;
+                if (!arrow && name == "arguments" && def.orig.length == 1) return;
                 names.set(name, true);
                 scope.enclosed.push(def);
                 scope.variables.set(name, def);
@@ -13364,12 +13416,12 @@ Compressor.prototype.compress = function(node) {
                         if (value) body.push(make_node(AST_SimpleStatement, call, { body: value }));
                         return;
                     }
-                    body.push(make_node(AST_Var, call, {
-                        definitions: [ make_node(AST_VarDef, call, {
-                            name: argname.convert_symbol(AST_SymbolVar, process),
-                            value: value || make_node(AST_Undefined, call).transform(compressor),
-                        }) ],
-                    }));
+                    var defn = make_node(AST_VarDef, call, {
+                        name: argname.convert_symbol(AST_SymbolVar, process),
+                        value: value || make_node(AST_Undefined, call).transform(compressor),
+                    });
+                    if (argname instanceof AST_SymbolFunarg) insert_assign(argname.definition(), defn);
+                    body.push(make_node(AST_Var, call, { definitions: [ defn ] }));
                 });
                 if (values.length) body.push(make_node(AST_SimpleStatement, call, {
                     body: make_sequence(call, values),
@@ -13500,6 +13552,12 @@ Compressor.prototype.compress = function(node) {
         def(AST_LabeledStatement, function(compressor, scope, no_return, in_loop) {
             var body = this.body.try_inline(compressor, scope, no_return, in_loop);
             if (!body) return;
+            if (this.body instanceof AST_IterationStatement && body instanceof AST_BlockStatement) {
+                var loop = body.body.pop();
+                this.body = loop;
+                body.body.push(this);
+                return body;
+            }
             this.body = body;
             return this;
         });

lib/minify.js

@@ -96,15 +96,14 @@ function minify(files, options) {
         }, true);
         if (options.validate) AST_Node.enable_validation();
         var timings = options.timings && { start: Date.now() };
-        if (options.rename === undefined) options.rename = options.compress && options.mangle;
         if (options.annotations !== undefined) set_shorthand("annotations", options, [ "compress", "output" ]);
         if (options.ie8) options.ie = options.ie || options.ie8;
-        if (options.ie) set_shorthand("ie", options, [ "compress", "mangle", "output" ]);
-        if (options.keep_fargs) set_shorthand("keep_fargs", options, [ "compress", "mangle" ]);
-        if (options.keep_fnames) set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
-        if (options.toplevel) set_shorthand("toplevel", options, [ "compress", "mangle" ]);
-        if (options.v8) set_shorthand("v8", options, [ "mangle", "output" ]);
-        if (options.webkit) set_shorthand("webkit", options, [ "compress", "mangle", "output" ]);
+        if (options.ie) set_shorthand("ie", options, [ "compress", "mangle", "output", "rename" ]);
+        if (options.keep_fargs) set_shorthand("keep_fargs", options, [ "compress", "mangle", "rename" ]);
+        if (options.keep_fnames) set_shorthand("keep_fnames", options, [ "compress", "mangle", "rename" ]);
+        if (options.toplevel) set_shorthand("toplevel", options, [ "compress", "mangle", "rename" ]);
+        if (options.v8) set_shorthand("v8", options, [ "mangle", "output", "rename" ]);
+        if (options.webkit) set_shorthand("webkit", options, [ "compress", "mangle", "output", "rename" ]);
         var quoted_props;
         if (options.mangle) {
             options.mangle = defaults(options.mangle, {
@@ -135,6 +134,7 @@ function minify(files, options) {
             init_cache(options.mangle.cache);
             init_cache(options.mangle.properties.cache);
         }
+        if (options.rename === undefined) options.rename = options.compress && options.mangle;
         if (options.sourceMap) {
             options.sourceMap = defaults(options.sourceMap, {
                 content: null,
@@ -190,8 +190,8 @@ function minify(files, options) {
         if (options.validate) toplevel.validate_ast();
         if (timings) timings.rename = Date.now();
         if (options.rename) {
-            toplevel.figure_out_scope(options.mangle);
-            toplevel.expand_names(options.mangle);
+            toplevel.figure_out_scope(options.rename);
+            toplevel.expand_names(options.rename);
         }
         if (timings) timings.compress = Date.now();
         if (options.compress) {

lib/parse.js

@@ -1194,10 +1194,10 @@ function parse($TEXT, options) {
     }
 
     function for_() {
-        var await = is("name", "await") && next();
+        var await_token = is("name", "await") && next();
         expect("(");
         var init = null;
-        if (await || !is("punc", ";")) {
+        if (await_token || !is("punc", ";")) {
             init = is("keyword", "const")
                 ? (next(), const_(true))
                 : is("name", "let") && is_vardefs()
@@ -1206,7 +1206,7 @@ function parse($TEXT, options) {
                 ? (next(), var_(true))
                 : expression(true);
             var ctor;
-            if (await) {
+            if (await_token) {
                 expect_token("name", "of");
                 ctor = AST_ForAwaitOf;
             } else if (is("operator", "in")) {

lib/scope.js

@@ -469,6 +469,7 @@ AST_Lambda.DEFMETHOD("init_vars", function(parent_scope) {
     this.uses_arguments = false;
     this.def_variable(new AST_SymbolFunarg({
         name: "arguments",
+        scope: this,
         start: this.start,
         end: this.end,
     }));

package.json

@@ -3,7 +3,7 @@
   "description": "JavaScript parser, mangler/compressor and beautifier toolkit",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.15.3",
+  "version": "3.15.5",
   "engines": {
     "node": ">=0.8.0"
   },

test/compress.js

@@ -183,13 +183,11 @@ function parse_test(file) {
 function reminify(orig_options, input_code, input_formatted, stdout) {
     for (var i = 0; i < minify_options.length; i++) {
         var options = JSON.parse(minify_options[i]);
-        if (options.compress) [
+        [
             "keep_fargs",
             "keep_fnames",
         ].forEach(function(name) {
-            if (name in orig_options) {
-                options.compress[name] = orig_options[name];
-            }
+            if (name in orig_options) options[name] = orig_options[name];
         });
         var options_formatted = JSON.stringify(options, null, 4);
         options.validate = true;

test/compress/arrows.js

@@ -1018,3 +1018,91 @@ issue_5356: {
     expect_stdout: "NaN"
     node_version: ">=4"
 }
+
+issue_5414_1: {
+    options = {
+        arrows: true,
+        if_return: true,
+        inline: true,
+        toplevel: true,
+    }
+    input: {
+        (() => {
+            (() => {
+                if (!console)
+                    var arguments = 42;
+                while (console.log(arguments));
+            })();
+        })();
+    }
+    expect: {
+        (() => {
+            if (!console)
+                var arguments = 42;
+            while (console.log(arguments));
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+issue_5414_2: {
+    options = {
+        arrows: true,
+        inline: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        (() => {
+            (() => {
+                if (!console)
+                    var arguments = 42;
+                while (console.log(arguments));
+            })();
+        })();
+    }
+    expect: {
+        (() => {
+            if (!console)
+                var arguments = 42;
+            while (console.log(arguments));
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}
+
+issue_5416: {
+    options = {
+        dead_code: true,
+        evaluate: true,
+        inline: true,
+        loops: true,
+        unused: true,
+    }
+    input: {
+        var f = () => {
+            while ((() => {
+                console;
+                var a = function g(arguments) {
+                    console.log(arguments);
+                }();
+            })());
+        };
+        f();
+    }
+    expect: {
+        var f = () => {
+            {
+                arguments = void 0;
+                console;
+                console.log(arguments);
+                var arguments;
+            }
+        };
+        f();
+    }
+    expect_stdout: "undefined"
+    node_version: ">=4"
+}

test/compress/classes.js

@@ -939,6 +939,8 @@ keep_fnames: {
         class Foo {}
         console.log(Foo.name, class Bar {}.name);
     }
+    expect_stdout: "Foo Bar"
+    node_version: ">=4"
 }
 
 issue_805_1: {
@@ -2502,3 +2504,100 @@ issue_5352: {
     expect_stdout: "PASS"
     node_version: ">=12"
 }
+
+issue_5387: {
+    options = {
+        properties: true,
+    }
+    input: {
+        "use strict";
+        (function(a) {
+            try {
+                class A extends a {}
+            } catch (e) {
+                console.log("PASS");
+            }
+        })({
+            f() {
+                return this;
+            }
+        }.f);
+    }
+    expect: {
+        "use strict";
+        (function(a) {
+            try {
+                class A extends a {}
+            } catch (e) {
+                console.log("PASS");
+            }
+        })({
+            f() {
+                return this;
+            }
+        }.f);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=4"
+}
+
+issue_5389: {
+    options = {
+        collapse_vars: true,
+        toplevel: true,
+    }
+    input: {
+        function log(m, n) {
+            console.log(m, n);
+        }
+        var a = log;
+        class A {
+            [a = "FAIL"] = a = "PASS";
+        }
+        var b = new A();
+        log(a, b.FAIL);
+    }
+    expect: {
+        function log(m, n) {
+            console.log(m, n);
+        }
+        var a = log;
+        class A {
+            [a = "FAIL"] = a = "PASS";
+        }
+        var b = new A();
+        log(a, b.FAIL);
+    }
+    expect_stdout: "PASS PASS"
+    node_version: ">=12"
+}
+
+issue_5436: {
+    options = {
+        merge_vars: true,
+    }
+    input: {
+        function f(a) {
+            class A {
+                p = a;
+            }
+            var b = "FAIL";
+            A == b && b();
+            return new A();
+        }
+        console.log(f("PASS").p);
+    }
+    expect: {
+        function f(a) {
+            class A {
+                p = a;
+            }
+            var b = "FAIL";
+            A == b && b();
+            return new A();
+        }
+        console.log(f("PASS").p);
+    }
+    expect_stdout: "PASS"
+    node_version: ">=12"
+}

test/compress/collapse_vars.js

@@ -9925,3 +9925,57 @@ issue_5309_2: {
     }
     expect_stdout: "PASS"
 }
+
+issue_5394: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+    }
+    input: {
+        try {
+            throw A.p = (console.log("FAIL"), []), !1;
+        } catch (e) {
+            console.log(typeof e);
+        }
+    }
+    expect: {
+        try {
+            throw !(A.p = (console.log("FAIL"), []));
+        } catch (e) {
+            console.log(typeof e);
+        }
+    }
+    expect_stdout: "object"
+}
+
+issue_5396: {
+    options = {
+        collapse_vars: true,
+        merge_vars: true,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a, b;
+        function f() {}
+        b = 0;
+        new function g(c) {
+            var d = a && g(e), e = ++d, i = [ 42 ];
+            for (var j in i)
+                console.log("PASS"),
+                i;
+        }();
+    }
+    expect: {
+        var a, b;
+        function f() {}
+        b = 0;
+        (function g(c) {
+            a && g();
+            for (var j in [ 42 ])
+                console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}

test/compress/default-values.js

@@ -2209,3 +2209,33 @@ issue_5340_3: {
     expect_stdout: "undefined"
     node_version: ">=6"
 }
+
+issue_5407: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        (function(a) {
+            for (var i = 0; i < 2; i++)
+                (function(b = 4) {
+                    console.log(b);
+                    a = 2;
+                })(a);
+        })();
+    }
+    expect: {
+        (function(a) {
+            for (var i = 0; i < 2; i++)
+                (function(b = 4) {
+                    console.log(b);
+                    a = 2;
+                })(a);
+        })();
+    }
+    expect_stdout: [
+        "4",
+        "2",
+    ]
+    node_version: ">=6"
+}

test/compress/destructured.js

@@ -3497,3 +3497,72 @@ issue_5370: {
     expect_stdout: true
     node_version: ">=6"
 }
+
+issue_5405_1: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+    }
+    input: {
+        var [ a ] = [ {} ];
+        console.log(a === a ? "PASS" : "FAIL");
+    }
+    expect: {
+        var [ a ] = [ {} ];
+        console.log(true ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5405_2: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unsafe: true,
+    }
+    input: {
+        var { p: a } = { p: [] };
+        console.log(a === a ? "PASS" : "FAIL");
+    }
+    expect: {
+        var { p: a } = { p: [] };
+        console.log(true ? "PASS" : "FAIL");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=6"
+}
+
+issue_5423: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a, b;
+        function f({
+            [function() {
+                if (++a)
+                    return 42;
+            }()]: c
+        }) {}
+        f(b = f);
+        console.log(typeof b);
+    }
+    expect: {
+        var a, b;
+        function f({
+            [function() {
+                if (++a)
+                    return 42;
+            }()]: c
+        }) {}
+        f(b = f);
+        console.log(typeof b);
+    }
+    expect_stdout: "function"
+    node_version: ">=6"
+}

test/compress/evaluate.js

@@ -3349,3 +3349,30 @@ issue_5362_2: {
     }
     expect_stdout: "true"
 }
+
+issue_5380: {
+    options = {
+        evaluate: true,
+        keep_fnames: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function f(b) {
+            return function g() {
+                for (b in { PASS: 42 });
+            }(), b;
+        }("FAIL");
+        console.log(a);
+    }
+    expect: {
+        var a = function f(b) {
+            return function g() {
+                for (b in { PASS: 42 });
+            }(), b;
+        }("FAIL");
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}

test/compress/functions.js

@@ -3557,6 +3557,27 @@ functions_inner_var: {
     expect_stdout: "undefined undefined"
 }
 
+functions_keep_fnames: {
+    options = {
+        functions: true,
+        keep_fnames: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var FAIL = function PASS() {};
+        FAIL.p = 42;
+        console.log(FAIL.name, FAIL.p);
+    }
+    expect: {
+        var FAIL = function PASS() {};
+        FAIL.p = 42;
+        console.log(FAIL.name, FAIL.p);
+    }
+    expect_stdout: "PASS 42"
+}
+
 issue_2437: {
     options = {
         collapse_vars: true,
@@ -8329,3 +8350,51 @@ issue_5376_2: {
     }
     expect_stdout: Error("PASS")
 }
+
+issue_5401: {
+    options = {
+        inline: true,
+    }
+    input: {
+        L: for (var a in function() {
+            while (console.log("PASS"));
+        }(), a) do {
+            continue L;
+        } while (console.log("FAIL"));
+    }
+    expect: {
+        while (console.log("PASS"));
+        L: for (var a in a) do {
+            continue L;
+        } while (console.log("FAIL"));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5409: {
+    options = {
+        inline: true,
+        merge_vars: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            (a = console) || FAIL(a);
+            (function(b) {
+                console.log(b && b);
+                while (!console);
+            })();
+        })();
+    }
+    expect: {
+        (function(a) {
+            (a = console) || FAIL(a);
+            a = void 0;
+            console.log(a && a);
+            while (!console);
+            return;
+        })();
+    }
+    expect_stdout: "undefined"
+}

test/compress/hoist_vars.js

@@ -224,8 +224,7 @@ issue_4489: {
         console.log(k);
     }
     expect: {
-        !(A = 0);
-        for (var k in true);
+        for (var k in !(A = 0));
         console.log(k);
     }
     expect_stdout: "undefined"
@@ -407,9 +406,9 @@ issue_4893_2: {
     expect: {
         try{
             (function() {
-                var b;
-                b = null;
-                b.p += 42;
+                var a;
+                a = null;
+                a.p += 42;
             })();
         } catch (e) {
             console.log("PASS");
@@ -530,3 +529,77 @@ issue_5378: {
         "undefined",
     ]
 }
+
+issue_5411_1: {
+    options = {
+        collapse_vars: true,
+        dead_code: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+    }
+    input: {
+        var a = "PASS";
+        b++;
+        b = a;
+        var b = b, c = c && c[b];
+        console.log(b);
+    }
+    expect: {
+        var b, c, a = "PASS";
+        b++;
+        b = a;
+        c = c && c[b];
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5411_2: {
+    options = {
+        collapse_vars: true,
+        dead_code: true,
+        evaluate: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        b++;
+        b = a;
+        var b = b, c = c && c[b];
+        console.log(b);
+    }
+    expect: {
+        var b, c;
+        b++;
+        b = "PASS",
+        c = c && c[b];
+        console.log(b);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_5411_3: {
+    options = {
+        collapse_vars: true,
+        hoist_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+    }
+    input: {
+        var a = console;
+        a++;
+        var a = A = a;
+        console.log(A);
+    }
+    expect: {
+        var a = console;
+        a = A = ++a;
+        console.log(A);
+    }
+    expect_stdout: "NaN"
+}

test/compress/keep_fargs.js

@@ -1258,8 +1258,7 @@ issues_3267_1: {
     }
     expect: {
         !function() {
-            var i = Object();
-            if (i)
+            if (Object())
                 return console.log("PASS");
             throw "FAIL";
         }();

test/compress/merge_vars.js

@@ -3702,3 +3702,33 @@ issue_5182: {
     ]
     node_version: ">=4"
 }
+
+issue_5420: {
+    options = {
+        merge_vars: true,
+        toplevel: true,
+    }
+    input: {
+        do {
+            var a = "FAIL 1";
+            a && a.p;
+            a = "FAIL 2";
+            try {
+                continue;
+            } catch (e) {}
+            var b = "FAIL 3";
+        } while (console.log(b || "PASS"));
+    }
+    expect: {
+        do {
+            var a = "FAIL 1";
+            a && a.p;
+            a = "FAIL 2";
+            try {
+                continue;
+            } catch (e) {}
+            var b = "FAIL 3";
+        } while (console.log(b || "PASS"));
+    }
+    expect_stdout: "PASS"
+}

test/compress/reduce_vars.js

@@ -6689,8 +6689,7 @@ issues_3267_1: {
     }
     expect: {
         !function(x) {
-            var i = Object();
-            if (i)
+            if (Object())
                 return console.log("PASS");
             throw "FAIL";
         }();
@@ -7862,3 +7861,38 @@ issue_5324: {
     }
     expect_stdout: "NaN"
 }
+
+issue_5434: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function(a) {
+            for (var i = 0; i < 2; i++) {
+                var b = "FAIL";
+                f && f();
+                a = b;
+                var f = function() {
+                    b = "PASS";
+                };
+            }
+            return a;
+        }());
+    }
+    expect: {
+        console.log(function(a) {
+            for (var i = 0; i < 2; i++) {
+                var b = "FAIL";
+                f && f();
+                a = b;
+                var f = function() {
+                    b = "PASS";
+                };
+            }
+            return a;
+        }());
+    }
+    expect_stdout: "PASS"
+}

test/compress/rests.js

@@ -1323,3 +1323,43 @@ issue_5370: {
     expect_stdout: true
     node_version: ">=6"
 }
+
+issue_5391: {
+    options = {
+        evaluate: true,
+        keep_fargs: false,
+        objects: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a, b = function f({
+            p: {},
+            ...c
+        }) {
+            while (c.q);
+        }({
+            p: {
+                r: a++,
+                r: 0,
+            }
+        });
+        console.log(a);
+    }
+    expect: {
+        (function({
+            p: {},
+            ...c
+        }) {
+            while (c.q);
+        })({
+            p: 0,
+        });
+        console.log(NaN);
+    }
+    expect_stdout: "NaN"
+    node_version: ">=8.3.0"
+}

test/compress/spreads.js

@@ -1166,3 +1166,31 @@ issue_5006: {
     expect_stdout: "PASS"
     node_version: ">=6"
 }
+
+issue_5382: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        ({
+            f() {
+                ({ ...this });
+            },
+            get p() {
+                console.log("PASS");
+            },
+        }).f();
+    }
+    expect: {
+        ({
+            f() {
+                ({ ...this });
+            },
+            get p() {
+                console.log("PASS");
+            },
+        }).f();
+    }
+    expect_stdout: "PASS"
+    node_version: ">=8.3.0"
+}

test/compress/yields.js

@@ -1451,3 +1451,99 @@ issue_5177: {
     expect_stdout: "function"
     node_version: ">=4"
 }
+
+issue_5385_1: {
+    options = {
+        inline: true,
+    }
+    input: {
+        (async function*() {
+            (function() {
+                try {
+                    return console.log("foo");
+                } finally {
+                    return console.log("bar");
+                }
+                console.log("baz");
+            })();
+        })().next();
+        console.log("moo");
+    }
+    expect: {
+        (async function*() {
+            (function() {
+                try {
+                    return console.log("foo");
+                } finally {
+                    return console.log("bar");
+                }
+                console.log("baz");
+            })();
+        })().next();
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+    ]
+    node_version: ">=10"
+}
+
+issue_5385_2: {
+    options = {
+        inline: true,
+    }
+    input: {
+        (async function*() {
+            return function() {
+                try {
+                    return console.log("foo");
+                } finally {
+                    return console.log("bar");
+                }
+            }();
+        })().next();
+        console.log("moo");
+    }
+    expect: {
+        (async function*() {
+            return function() {
+                try {
+                    return console.log("foo");
+                } finally {
+                    return console.log("bar");
+                }
+            }();
+        })().next();
+        console.log("moo");
+    }
+    expect_stdout: [
+        "foo",
+        "bar",
+        "moo",
+    ]
+    node_version: ">=10"
+}
+
+issue_5425: {
+    options = {
+        assignments: true,
+        ie: true,
+        toplevel: true,
+        unused: true,
+        yields: true,
+    }
+    input: {
+        var a = "FAIL";
+        var b = function* f() {}(a ? a = "PASS" : 42);
+        console.log(a, typeof f);
+    }
+    expect: {
+        var a = "FAIL";
+        (function* f() {})(a && (a = "PASS"));
+        console.log(a, typeof f);
+    }
+    expect_stdout: "PASS undefined"
+    node_version: ">=4"
+}

test/mocha/reduce.js

@@ -434,7 +434,7 @@ describe("test/reduce.js", function() {
             "// }",
         ].join("\n"));
     });
-    it("Should transform `export default` correctly", function() {
+    it("Should transform `export default class` correctly", function() {
         var result = reduce_test(read("test/input/reduce/export_default.js"), {
             compress: false,
             toplevel: true,
@@ -448,4 +448,41 @@ describe("test/reduce.js", function() {
             "// }",
         ].join("\n"));
     });
+    it("Should transform `export default function` correctly", function() {
+        var code = [
+            "for (var k in this)",
+            "    console.log(k);",
+            "export default (function f() {});",
+            "console.log(k);",
+        ].join("\n");
+        var result = reduce_test(code, {
+            mangle: false,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, [
+            "// Can't reproduce test failure",
+            "// minify options: {",
+            '//   "mangle": false',
+            "// }",
+        ].join("\n"));
+    });
+    it("Should transform `export default (42)` correctly", function() {
+        var code = [
+            "export default (42);",
+            "for (var k in this)",
+            "    console.log(k);",
+        ].join("\n");
+        var result = reduce_test(code, {
+            compress: false,
+            mangle: false,
+        });
+        if (result.error) throw result.error;
+        assert.strictEqual(result.code, [
+            "// Can't reproduce test failure",
+            "// minify options: {",
+            '//   "compress": false,',
+            '//   "mangle": false',
+            "// }",
+        ].join("\n"));
+    });
 });

test/sandbox.js

@@ -52,12 +52,17 @@ exports.same_stdout = semver.satisfies(process.version, "0.12") ? function(expec
     return typeof expected == typeof actual && strip_func_ids(expected) == strip_func_ids(actual);
 };
 exports.patch_module_statements = function(code) {
-    var count = 0, imports = [];
-    code = code.replace(/\bexport(?:\s*\{[^{}]*}\s*?(?:$|\n|;)|\s+default\b(?:\s*(\(|\{|class\s*\{|class\s+(?=extends\b)|(?:async\s+)?function\s*(?:\*\s*)?\())?|\b)/g, function(match, header) {
+    var count = 0, has_default = "", imports = [], strict_mode = "";
+    code = code.replace(/^\s*("|')use strict\1\s*;?/, function(match) {
+        strict_mode = match;
+        return "";
+    }).replace(/\bexport(?:\s*\{[^{}]*}\s*?(?:$|\n|;)|\s+default\b(?:\s*(\(|\{|class\s*\{|class\s+(?=extends\b)|(?:async\s+)?function\s*(?:\*\s*)?\())?|\b)/g, function(match, header) {
+        if (/^export\s+default/.test(match)) has_default = "var _uglify_export_default_;";
         if (!header) return "";
         if (header.length == 1) return "0, " + header;
-        do {
-            var name = "_export_default_" + ++count;
+        var name = "_uglify_export_default_";
+        if (/^class\b/.test(header)) do {
+            name = "_uglify_export_default_" + ++count;
         } while (code.indexOf(name) >= 0);
         return header.slice(0, -1) + " " + name + header.slice(-1);
     }).replace(/\bimport\.meta\b/g, function() {
@@ -76,7 +81,7 @@ exports.patch_module_statements = function(code) {
         return "";
     });
     imports.push("");
-    return imports.join("\n") + code;
+    return strict_mode + has_default + imports.join("\n") + code;
 };
 
 function is_error(result) {

test/ufuzz/index.js

@@ -128,7 +128,7 @@ for (var i = 2; i < process.argv.length; ++i) {
 
 var SUPPORT = function(matrix) {
     for (var name in matrix) {
-        matrix[name] = typeof sandbox.run_code(matrix[name]) == "string";
+        matrix[name] = !sandbox.is_error(sandbox.run_code(matrix[name]));
     }
     return matrix;
 }({
@@ -1824,7 +1824,13 @@ function createClassLiteral(recurmax, stmtDepth, canThrow, name) {
             declared.push(internal);
         }
         if (SUPPORT.class_field && rng(2)) {
-            s += internal || createObjectKey(recurmax, stmtDepth, canThrow);
+            if (internal) {
+                s += internal;
+            } else if (fixed && bug_static_class_field) {
+                s += getDotKey();
+            } else {
+                s += createObjectKey(recurmax, stmtDepth, canThrow);
+            }
             if (rng(5)) {
                 async = bug_async_class_await && fixed && 0;
                 generator = false;
@@ -2110,7 +2116,7 @@ function try_beautify(code, toplevel, result, printfn, options) {
     } else if (options) {
         var uglified = UglifyJS.minify(beautified.code, JSON.parse(options));
         var expected, actual;
-        if (typeof uglify_code != "string" || uglified.error) {
+        if (sandbox.is_error(uglify_code) || uglified.error) {
             expected = uglify_code;
             actual = uglified.error;
         } else {
@@ -2147,7 +2153,7 @@ function log_suspects(minify_options, component) {
             m[component] = o;
             m.validate = true;
             var result = UglifyJS.minify(original_code, m);
-            if (typeof uglify_code != "string") {
+            if (sandbox.is_error(uglify_code)) {
                 return !sandbox.same_stdout(uglify_code, result.error);
             } else if (result.error) {
                 errorln("Error testing options." + component + "." + name);
@@ -2175,7 +2181,7 @@ function log_suspects_global(options, toplevel) {
         m[component] = false;
         m.validate = true;
         var result = UglifyJS.minify(original_code, m);
-        if (typeof uglify_code != "string") {
+        if (sandbox.is_error(uglify_code)) {
             return !sandbox.same_stdout(uglify_code, result.error);
         } else if (result.error) {
             errorln("Error testing options." + component);
@@ -2204,7 +2210,16 @@ function log(options) {
     errorln();
     errorln();
     errorln("//-------------------------------------------------------------");
-    if (typeof uglify_code == "string") {
+    if (sandbox.is_error(uglify_code)) {
+        errorln("// !!! uglify failed !!!");
+        errorln(uglify_code);
+        if (original_erred) {
+            errorln();
+            errorln();
+            errorln("original stacktrace:");
+            errorln(original_result);
+        }
+    } else {
         errorln("// uglified code");
         try_beautify(uglify_code, toplevel, uglify_result, errorln);
         errorln();
@@ -2213,15 +2228,6 @@ function log(options) {
         errorln(original_result);
         errorln("uglified result:");
         errorln(uglify_result);
-    } else {
-        errorln("// !!! uglify failed !!!");
-        errorln(uglify_code);
-        if (errored) {
-            errorln();
-            errorln();
-            errorln("original stacktrace:");
-            errorln(original_result);
-        }
     }
     errorln("//-------------------------------------------------------------");
     if (!ok) {
@@ -2426,22 +2432,23 @@ var beautify_options = {
     },
 };
 var minify_options = require("./options.json");
-if (typeof sandbox.run_code("A:if (0) B:; else B:;") != "string") {
+if (sandbox.is_error(sandbox.run_code("A:if (0) B:; else B:;"))) {
     minify_options.forEach(function(o) {
         if (!("mangle" in o)) o.mangle = {};
         if (o.mangle) o.mangle.v8 = true;
     });
 }
 var bug_async_arrow_rest = function() {};
-if (SUPPORT.arrow && SUPPORT.async && SUPPORT.rest && typeof sandbox.run_code("async (a = f(...[], b)) => 0;") != "string") {
+if (SUPPORT.arrow && SUPPORT.async && SUPPORT.rest && sandbox.is_error(sandbox.run_code("async (a = f(...[], b)) => 0;"))) {
     bug_async_arrow_rest = function(ex) {
         return ex.name == "SyntaxError" && ex.message == "Rest parameter must be last formal parameter";
     };
 }
-var bug_async_class_await = SUPPORT.async && SUPPORT.class_field && typeof sandbox.run_code("var await; async function f() { class A { static p = await; } }") != "string";
-var bug_for_of_async = SUPPORT.for_await_of && typeof sandbox.run_code("var async; for (async of []);") != "string";
-var bug_for_of_var = SUPPORT.for_of && SUPPORT.let && typeof sandbox.run_code("try {} catch (e) { for (var e of []); }") != "string";
-if (SUPPORT.destructuring && typeof sandbox.run_code("console.log([ 1 ], {} = 2);") != "string") {
+var bug_async_class_await = SUPPORT.async && SUPPORT.class_field && sandbox.is_error(sandbox.run_code("var await; async function f() { class A { static p = await; } }"));
+var bug_for_of_async = SUPPORT.for_await_of && sandbox.is_error(sandbox.run_code("var async; for (async of []);"));
+var bug_for_of_var = SUPPORT.for_of && SUPPORT.let && sandbox.is_error(sandbox.run_code("try {} catch (e) { for (var e of []); }"));
+var bug_static_class_field = SUPPORT.class_field && sandbox.is_error(sandbox.run_code("class A { static 42; static get 42() {} }"));
+if (SUPPORT.destructuring && sandbox.is_error(sandbox.run_code("console.log([ 1 ], {} = 2);"))) {
     beautify_options.output.v8 = true;
     minify_options.forEach(function(o) {
         if (!("output" in o)) o.output = {};
@@ -2450,7 +2457,7 @@ if (SUPPORT.destructuring && typeof sandbox.run_code("console.log([ 1 ], {} = 2)
 }
 beautify_options = JSON.stringify(beautify_options);
 minify_options = minify_options.map(JSON.stringify);
-var original_code, original_result, errored;
+var original_code, original_result, original_erred;
 var uglify_code, uglify_result, ok;
 for (var round = 1; round <= num_iterations; round++) {
     process.stdout.write(round + " of " + num_iterations + "\r");
@@ -2458,7 +2465,7 @@ for (var round = 1; round <= num_iterations; round++) {
     original_code = createTopLevelCode();
     var orig_result = [ run_code(original_code), run_code(original_code, true) ];
     if (orig_result.some(function(result, toplevel) {
-        if (typeof result == "string") return;
+        if (!sandbox.is_error(result)) return;
         println();
         println();
         println("//=============================================================");
@@ -2480,19 +2487,20 @@ for (var round = 1; round <= num_iterations; round++) {
         o.validate = true;
         uglify_code = UglifyJS.minify(original_code, o);
         original_result = orig_result[toplevel ? 1 : 0];
-        errored = typeof original_result != "string";
+        original_erred = sandbox.is_error(original_result);
         if (!uglify_code.error) {
             uglify_code = uglify_code.code;
             uglify_result = run_code(uglify_code, toplevel);
             ok = sandbox.same_stdout(original_result, uglify_result);
+            var uglify_erred = sandbox.is_error(uglify_result);
             // ignore v8 parser bug
-            if (!ok && bug_async_arrow_rest(uglify_result)) ok = true;
+            if (!ok && uglify_erred && bug_async_arrow_rest(uglify_result)) ok = true;
             // ignore runtime platform bugs
-            if (!ok && uglify_result.message == "Script execution aborted.") ok = true;
+            if (!ok && uglify_erred && uglify_result.message == "Script execution aborted.") ok = true;
             // handle difference caused by time-outs
             if (!ok) {
-                if (errored && is_error_timeout(original_result)) {
-                    if (is_error_timeout(uglify_result)) {
+                if (original_erred && is_error_timeout(original_result)) {
+                    if (uglify_erred && is_error_timeout(uglify_result)) {
                         // ignore difference in error message
                         ok = true;
                     } else {
@@ -2500,21 +2508,23 @@ for (var round = 1; round <= num_iterations; round++) {
                         if (!orig_result[toplevel ? 3 : 2]) orig_result[toplevel ? 3 : 2] = run_code(original_code, toplevel, 10000);
                         ok = sandbox.same_stdout(orig_result[toplevel ? 3 : 2], uglify_result);
                     }
-                } else if (is_error_timeout(uglify_result)) {
+                } else if (uglify_erred && is_error_timeout(uglify_result)) {
                     // ignore spurious time-outs
                     var waited_result = run_code(uglify_code, toplevel, 10000);
                     ok = sandbox.same_stdout(original_result, waited_result);
                 }
             }
             // ignore declaration order of global variables
-            if (!ok && !toplevel && uglify_result.name != "SyntaxError" && original_result.name != "SyntaxError") {
-                ok = sandbox.same_stdout(run_code(sort_globals(original_code)), run_code(sort_globals(uglify_code)));
+            if (!ok && !toplevel) {
+                if (!(original_erred && original_result.name == "SyntaxError") && !(uglify_erred && uglify_result.name == "SyntaxError")) {
+                    ok = sandbox.same_stdout(run_code(sort_globals(original_code)), run_code(sort_globals(uglify_code)));
+                }
             }
             // ignore numerical imprecision caused by `unsafe_math`
-            if (!ok && o.compress && o.compress.unsafe_math && typeof original_result == typeof uglify_result) {
-                if (typeof original_result == "string") {
+            if (!ok && o.compress && o.compress.unsafe_math) {
+                if (typeof original_result == "string" && typeof uglify_result == "string") {
                     ok = fuzzy_match(original_result, uglify_result);
-                } else if (sandbox.is_error(original_result)) {
+                } else if (original_erred && uglify_erred) {
                     ok = original_result.name == uglify_result.name && fuzzy_match(original_result.message, uglify_result.message);
                 }
                 if (!ok) {
@@ -2523,19 +2533,19 @@ for (var round = 1; round <= num_iterations; round++) {
                 }
             }
             // ignore difference in error message caused by Temporal Dead Zone
-            if (!ok && errored && uglify_result.name == "ReferenceError" && original_result.name == "ReferenceError") ok = true;
+            if (!ok && original_erred && uglify_erred && original_result.name == "ReferenceError" && uglify_result.name == "ReferenceError") ok = true;
             // ignore difference due to implicit strict-mode in `class`
             if (!ok && /\bclass\b/.test(original_code)) {
                 var original_strict = run_code('"use strict";\n' + original_code, toplevel);
-                if (/^(Syntax|Type)Error$/.test(uglify_result.name)) {
-                    ok = typeof original_strict != "string";
+                if (uglify_erred && /^(Syntax|Type)Error$/.test(uglify_result.name)) {
+                    ok = sandbox.is_error(original_strict);
                 } else {
                     ok = sandbox.same_stdout(original_strict, uglify_result);
                 }
             }
             // ignore difference in error message caused by `import` symbol redeclaration
-            if (!ok && errored && /\bimport\b/.test(original_code)) {
-                if (is_error_redeclaration(uglify_result) && is_error_redeclaration(original_result)) ok = true;
+            if (!ok && original_erred && uglify_erred && /\bimport\b/.test(original_code)) {
+                if (is_error_redeclaration(original_result) && is_error_redeclaration(uglify_result)) ok = true;
             }
             // ignore difference due to `__proto__` assignment
             if (!ok && /\b__proto__\b/.test(original_code)) {
@@ -2544,24 +2554,32 @@ for (var round = 1; round <= num_iterations; round++) {
                 ok = sandbox.same_stdout(original_proto, uglify_proto);
             }
             // ignore difference in error message caused by `in`
-            if (!ok && errored && is_error_in(uglify_result) && is_error_in(original_result)) ok = true;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_in(original_result) && is_error_in(uglify_result)) ok = true;
+            }
             // ignore difference in error message caused by spread syntax
-            if (!ok && errored && is_error_spread(uglify_result) && is_error_spread(original_result)) ok = true;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_spread(original_result) && is_error_spread(uglify_result)) ok = true;
+            }
             // ignore difference in depth of termination caused by infinite recursion
-            if (!ok && errored && is_error_recursion(original_result)) {
-                if (is_error_recursion(uglify_result) || typeof uglify_result == "string") ok = true;
+            if (!ok && original_erred && is_error_recursion(original_result)) {
+                if (!uglify_erred || is_error_recursion(uglify_result)) ok = true;
             }
             // ignore difference in error message caused by destructuring
-            if (!ok && errored && is_error_destructuring(uglify_result) && is_error_destructuring(original_result)) {
-                ok = true;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_destructuring(original_result) && is_error_destructuring(uglify_result)) ok = true;
             }
             // ignore difference in error message caused by call on class
-            if (!ok && errored && is_error_class_constructor(uglify_result) && is_error_class_constructor(original_result)) {
-                ok = true;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_class_constructor(original_result) && is_error_class_constructor(uglify_result)) {
+                    ok = true;
+                }
             }
             // ignore difference in error message caused by setting getter-only property
-            if (!ok && errored && is_error_getter_only_property(uglify_result) && is_error_getter_only_property(original_result)) {
-                ok = true;
+            if (!ok && original_erred && uglify_erred) {
+                if (is_error_getter_only_property(original_result) && is_error_getter_only_property(uglify_result)) {
+                    ok = true;
+                }
             }
             // ignore errors above when caught by try-catch
             if (!ok) {
@@ -2573,7 +2591,7 @@ for (var round = 1; round <= num_iterations; round++) {
             }
         } else {
             uglify_code = uglify_code.error;
-            ok = errored && uglify_code.name == original_result.name;
+            ok = original_erred && uglify_code.name == original_result.name;
         }
         if (verbose || (verbose_interval && !(round % INTERVAL_COUNT)) || !ok) log(options);
         if (!ok && isFinite(num_iterations)) {