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diff --git a/src/node_modules/terser/lib/ast.js b/src/node_modules/terser/lib/ast.js
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+/***********************************************************************
+
+  A JavaScript tokenizer / parser / beautifier / compressor.
+  https://github.com/mishoo/UglifyJS2
+
+  -------------------------------- (C) ---------------------------------
+
+                           Author: Mihai Bazon
+                         <mihai.bazon@gmail.com>
+                       http://mihai.bazon.net/blog
+
+  Distributed under the BSD license:
+
+    Copyright 2012 (c) Mihai Bazon <mihai.bazon@gmail.com>
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+        * Redistributions of source code must retain the above
+          copyright notice, this list of conditions and the following
+          disclaimer.
+
+        * Redistributions in binary form must reproduce the above
+          copyright notice, this list of conditions and the following
+          disclaimer in the documentation and/or other materials
+          provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY
+    EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+    PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
+    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+    TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+    THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+
+ ***********************************************************************/
+
+"use strict";
+
+import {
+    HOP,
+    MAP,
+    noop
+} from "./utils/index.js";
+import { parse } from "./parse.js";
+
+function DEFNODE(type, props, methods, base = AST_Node) {
+    if (!props) props = [];
+    else props = props.split(/\s+/);
+    var self_props = props;
+    if (base && base.PROPS)
+        props = props.concat(base.PROPS);
+    var code = "return function AST_" + type + "(props){ if (props) { ";
+    for (var i = props.length; --i >= 0;) {
+        code += "this." + props[i] + " = props." + props[i] + ";";
+    }
+    const proto = base && Object.create(base.prototype);
+    if (proto && proto.initialize || (methods && methods.initialize))
+        code += "this.initialize();";
+    code += "}";
+    code += "this.flags = 0;";
+    code += "}";
+    var ctor = new Function(code)();
+    if (proto) {
+        ctor.prototype = proto;
+        ctor.BASE = base;
+    }
+    if (base) base.SUBCLASSES.push(ctor);
+    ctor.prototype.CTOR = ctor;
+    ctor.prototype.constructor = ctor;
+    ctor.PROPS = props || null;
+    ctor.SELF_PROPS = self_props;
+    ctor.SUBCLASSES = [];
+    if (type) {
+        ctor.prototype.TYPE = ctor.TYPE = type;
+    }
+    if (methods) for (i in methods) if (HOP(methods, i)) {
+        if (i[0] === "$") {
+            ctor[i.substr(1)] = methods[i];
+        } else {
+            ctor.prototype[i] = methods[i];
+        }
+    }
+    ctor.DEFMETHOD = function(name, method) {
+        this.prototype[name] = method;
+    };
+    return ctor;
+}
+
+const has_tok_flag = (tok, flag) => Boolean(tok.flags & flag);
+const set_tok_flag = (tok, flag, truth) => {
+    if (truth) {
+        tok.flags |= flag;
+    } else {
+        tok.flags &= ~flag;
+    }
+};
+
+const TOK_FLAG_NLB          = 0b0001;
+const TOK_FLAG_QUOTE_SINGLE = 0b0010;
+const TOK_FLAG_QUOTE_EXISTS = 0b0100;
+
+class AST_Token {
+    constructor(type, value, line, col, pos, nlb, comments_before, comments_after, file) {
+        this.flags = (nlb ? 1 : 0);
+
+        this.type = type;
+        this.value = value;
+        this.line = line;
+        this.col = col;
+        this.pos = pos;
+        this.comments_before = comments_before;
+        this.comments_after = comments_after;
+        this.file = file;
+
+        Object.seal(this);
+    }
+
+    get nlb() {
+        return has_tok_flag(this, TOK_FLAG_NLB);
+    }
+
+    set nlb(new_nlb) {
+        set_tok_flag(this, TOK_FLAG_NLB, new_nlb);
+    }
+
+    get quote() {
+        return !has_tok_flag(this, TOK_FLAG_QUOTE_EXISTS)
+            ? ""
+            : (has_tok_flag(this, TOK_FLAG_QUOTE_SINGLE) ? "'" : '"');
+    }
+
+    set quote(quote_type) {
+        set_tok_flag(this, TOK_FLAG_QUOTE_SINGLE, quote_type === "'");
+        set_tok_flag(this, TOK_FLAG_QUOTE_EXISTS, !!quote_type);
+    }
+}
+
+var AST_Node = DEFNODE("Node", "start end", {
+    _clone: function(deep) {
+        if (deep) {
+            var self = this.clone();
+            return self.transform(new TreeTransformer(function(node) {
+                if (node !== self) {
+                    return node.clone(true);
+                }
+            }));
+        }
+        return new this.CTOR(this);
+    },
+    clone: function(deep) {
+        return this._clone(deep);
+    },
+    $documentation: "Base class of all AST nodes",
+    $propdoc: {
+        start: "[AST_Token] The first token of this node",
+        end: "[AST_Token] The last token of this node"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this);
+    },
+    walk: function(visitor) {
+        return this._walk(visitor); // not sure the indirection will be any help
+    },
+    _children_backwards: () => {}
+}, null);
+
+/* -----[ statements ]----- */
+
+var AST_Statement = DEFNODE("Statement", null, {
+    $documentation: "Base class of all statements",
+});
+
+var AST_Debugger = DEFNODE("Debugger", null, {
+    $documentation: "Represents a debugger statement",
+}, AST_Statement);
+
+var AST_Directive = DEFNODE("Directive", "value quote", {
+    $documentation: "Represents a directive, like \"use strict\";",
+    $propdoc: {
+        value: "[string] The value of this directive as a plain string (it's not an AST_String!)",
+        quote: "[string] the original quote character"
+    },
+}, AST_Statement);
+
+var AST_SimpleStatement = DEFNODE("SimpleStatement", "body", {
+    $documentation: "A statement consisting of an expression, i.e. a = 1 + 2",
+    $propdoc: {
+        body: "[AST_Node] an expression node (should not be instanceof AST_Statement)"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.body._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.body);
+    }
+}, AST_Statement);
+
+function walk_body(node, visitor) {
+    const body = node.body;
+    for (var i = 0, len = body.length; i < len; i++) {
+        body[i]._walk(visitor);
+    }
+}
+
+function clone_block_scope(deep) {
+    var clone = this._clone(deep);
+    if (this.block_scope) {
+        // TODO this is sometimes undefined during compression.
+        // But it should always have a value!
+        clone.block_scope = this.block_scope.clone();
+    }
+    return clone;
+}
+
+var AST_Block = DEFNODE("Block", "body block_scope", {
+    $documentation: "A body of statements (usually braced)",
+    $propdoc: {
+        body: "[AST_Statement*] an array of statements",
+        block_scope: "[AST_Scope] the block scope"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            walk_body(this, visitor);
+        });
+    },
+    _children_backwards(push) {
+        let i = this.body.length;
+        while (i--) push(this.body[i]);
+    },
+    clone: clone_block_scope
+}, AST_Statement);
+
+var AST_BlockStatement = DEFNODE("BlockStatement", null, {
+    $documentation: "A block statement",
+}, AST_Block);
+
+var AST_EmptyStatement = DEFNODE("EmptyStatement", null, {
+    $documentation: "The empty statement (empty block or simply a semicolon)"
+}, AST_Statement);
+
+var AST_StatementWithBody = DEFNODE("StatementWithBody", "body", {
+    $documentation: "Base class for all statements that contain one nested body: `For`, `ForIn`, `Do`, `While`, `With`",
+    $propdoc: {
+        body: "[AST_Statement] the body; this should always be present, even if it's an AST_EmptyStatement"
+    }
+}, AST_Statement);
+
+var AST_LabeledStatement = DEFNODE("LabeledStatement", "label", {
+    $documentation: "Statement with a label",
+    $propdoc: {
+        label: "[AST_Label] a label definition"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.label._walk(visitor);
+            this.body._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.body);
+        push(this.label);
+    },
+    clone: function(deep) {
+        var node = this._clone(deep);
+        if (deep) {
+            var label = node.label;
+            var def = this.label;
+            node.walk(new TreeWalker(function(node) {
+                if (node instanceof AST_LoopControl
+                    && node.label && node.label.thedef === def) {
+                    node.label.thedef = label;
+                    label.references.push(node);
+                }
+            }));
+        }
+        return node;
+    }
+}, AST_StatementWithBody);
+
+var AST_IterationStatement = DEFNODE("IterationStatement", "block_scope", {
+    $documentation: "Internal class.  All loops inherit from it.",
+    $propdoc: {
+        block_scope: "[AST_Scope] the block scope for this iteration statement."
+    },
+    clone: clone_block_scope
+}, AST_StatementWithBody);
+
+var AST_DWLoop = DEFNODE("DWLoop", "condition", {
+    $documentation: "Base class for do/while statements",
+    $propdoc: {
+        condition: "[AST_Node] the loop condition.  Should not be instanceof AST_Statement"
+    }
+}, AST_IterationStatement);
+
+var AST_Do = DEFNODE("Do", null, {
+    $documentation: "A `do` statement",
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.body._walk(visitor);
+            this.condition._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.condition);
+        push(this.body);
+    }
+}, AST_DWLoop);
+
+var AST_While = DEFNODE("While", null, {
+    $documentation: "A `while` statement",
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.condition._walk(visitor);
+            this.body._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.body);
+        push(this.condition);
+    },
+}, AST_DWLoop);
+
+var AST_For = DEFNODE("For", "init condition step", {
+    $documentation: "A `for` statement",
+    $propdoc: {
+        init: "[AST_Node?] the `for` initialization code, or null if empty",
+        condition: "[AST_Node?] the `for` termination clause, or null if empty",
+        step: "[AST_Node?] the `for` update clause, or null if empty"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            if (this.init) this.init._walk(visitor);
+            if (this.condition) this.condition._walk(visitor);
+            if (this.step) this.step._walk(visitor);
+            this.body._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.body);
+        if (this.step) push(this.step);
+        if (this.condition) push(this.condition);
+        if (this.init) push(this.init);
+    },
+}, AST_IterationStatement);
+
+var AST_ForIn = DEFNODE("ForIn", "init object", {
+    $documentation: "A `for ... in` statement",
+    $propdoc: {
+        init: "[AST_Node] the `for/in` initialization code",
+        object: "[AST_Node] the object that we're looping through"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.init._walk(visitor);
+            this.object._walk(visitor);
+            this.body._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.body);
+        if (this.object) push(this.object);
+        if (this.init) push(this.init);
+    },
+}, AST_IterationStatement);
+
+var AST_ForOf = DEFNODE("ForOf", "await", {
+    $documentation: "A `for ... of` statement",
+}, AST_ForIn);
+
+var AST_With = DEFNODE("With", "expression", {
+    $documentation: "A `with` statement",
+    $propdoc: {
+        expression: "[AST_Node] the `with` expression"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.expression._walk(visitor);
+            this.body._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.body);
+        push(this.expression);
+    },
+}, AST_StatementWithBody);
+
+/* -----[ scope and functions ]----- */
+
+var AST_Scope = DEFNODE("Scope", "variables functions uses_with uses_eval parent_scope enclosed cname", {
+    $documentation: "Base class for all statements introducing a lexical scope",
+    $propdoc: {
+        variables: "[Map/S] a map of name -> SymbolDef for all variables/functions defined in this scope",
+        functions: "[Map/S] like `variables`, but only lists function declarations",
+        uses_with: "[boolean/S] tells whether this scope uses the `with` statement",
+        uses_eval: "[boolean/S] tells whether this scope contains a direct call to the global `eval`",
+        parent_scope: "[AST_Scope?/S] link to the parent scope",
+        enclosed: "[SymbolDef*/S] a list of all symbol definitions that are accessed from this scope or any subscopes",
+        cname: "[integer/S] current index for mangling variables (used internally by the mangler)",
+    },
+    get_defun_scope: function() {
+        var self = this;
+        while (self.is_block_scope()) {
+            self = self.parent_scope;
+        }
+        return self;
+    },
+    clone: function(deep, toplevel) {
+        var node = this._clone(deep);
+        if (deep && this.variables && toplevel && !this._block_scope) {
+            node.figure_out_scope({}, {
+                toplevel: toplevel,
+                parent_scope: this.parent_scope
+            });
+        } else {
+            if (this.variables) node.variables = new Map(this.variables);
+            if (this.functions) node.functions = new Map(this.functions);
+            if (this.enclosed) node.enclosed = this.enclosed.slice();
+            if (this._block_scope) node._block_scope = this._block_scope;
+        }
+        return node;
+    },
+    pinned: function() {
+        return this.uses_eval || this.uses_with;
+    }
+}, AST_Block);
+
+var AST_Toplevel = DEFNODE("Toplevel", "globals", {
+    $documentation: "The toplevel scope",
+    $propdoc: {
+        globals: "[Map/S] a map of name -> SymbolDef for all undeclared names",
+    },
+    wrap_commonjs: function(name) {
+        var body = this.body;
+        var wrapped_tl = "(function(exports){'$ORIG';})(typeof " + name + "=='undefined'?(" + name + "={}):" + name + ");";
+        wrapped_tl = parse(wrapped_tl);
+        wrapped_tl = wrapped_tl.transform(new TreeTransformer(function(node) {
+            if (node instanceof AST_Directive && node.value == "$ORIG") {
+                return MAP.splice(body);
+            }
+        }));
+        return wrapped_tl;
+    },
+    wrap_enclose: function(args_values) {
+        if (typeof args_values != "string") args_values = "";
+        var index = args_values.indexOf(":");
+        if (index < 0) index = args_values.length;
+        var body = this.body;
+        return parse([
+            "(function(",
+            args_values.slice(0, index),
+            '){"$ORIG"})(',
+            args_values.slice(index + 1),
+            ")"
+        ].join("")).transform(new TreeTransformer(function(node) {
+            if (node instanceof AST_Directive && node.value == "$ORIG") {
+                return MAP.splice(body);
+            }
+        }));
+    }
+}, AST_Scope);
+
+var AST_Expansion = DEFNODE("Expansion", "expression", {
+    $documentation: "An expandible argument, such as ...rest, a splat, such as [1,2,...all], or an expansion in a variable declaration, such as var [first, ...rest] = list",
+    $propdoc: {
+        expression: "[AST_Node] the thing to be expanded"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.expression.walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.expression);
+    },
+});
+
+var AST_Lambda = DEFNODE("Lambda", "name argnames uses_arguments is_generator async", {
+    $documentation: "Base class for functions",
+    $propdoc: {
+        name: "[AST_SymbolDeclaration?] the name of this function",
+        argnames: "[AST_SymbolFunarg|AST_Destructuring|AST_Expansion|AST_DefaultAssign*] array of function arguments, destructurings, or expanding arguments",
+        uses_arguments: "[boolean/S] tells whether this function accesses the arguments array",
+        is_generator: "[boolean] is this a generator method",
+        async: "[boolean] is this method async",
+    },
+    args_as_names: function () {
+        var out = [];
+        for (var i = 0; i < this.argnames.length; i++) {
+            if (this.argnames[i] instanceof AST_Destructuring) {
+                out.push(...this.argnames[i].all_symbols());
+            } else {
+                out.push(this.argnames[i]);
+            }
+        }
+        return out;
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            if (this.name) this.name._walk(visitor);
+            var argnames = this.argnames;
+            for (var i = 0, len = argnames.length; i < len; i++) {
+                argnames[i]._walk(visitor);
+            }
+            walk_body(this, visitor);
+        });
+    },
+    _children_backwards(push) {
+        let i = this.body.length;
+        while (i--) push(this.body[i]);
+
+        i = this.argnames.length;
+        while (i--) push(this.argnames[i]);
+
+        if (this.name) push(this.name);
+    },
+}, AST_Scope);
+
+var AST_Accessor = DEFNODE("Accessor", null, {
+    $documentation: "A setter/getter function.  The `name` property is always null."
+}, AST_Lambda);
+
+var AST_Function = DEFNODE("Function", null, {
+    $documentation: "A function expression"
+}, AST_Lambda);
+
+var AST_Arrow = DEFNODE("Arrow", null, {
+    $documentation: "An ES6 Arrow function ((a) => b)"
+}, AST_Lambda);
+
+var AST_Defun = DEFNODE("Defun", null, {
+    $documentation: "A function definition"
+}, AST_Lambda);
+
+/* -----[ DESTRUCTURING ]----- */
+var AST_Destructuring = DEFNODE("Destructuring", "names is_array", {
+    $documentation: "A destructuring of several names. Used in destructuring assignment and with destructuring function argument names",
+    $propdoc: {
+        "names": "[AST_Node*] Array of properties or elements",
+        "is_array": "[Boolean] Whether the destructuring represents an object or array"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.names.forEach(function(name) {
+                name._walk(visitor);
+            });
+        });
+    },
+    _children_backwards(push) {
+        let i = this.names.length;
+        while (i--) push(this.names[i]);
+    },
+    all_symbols: function() {
+        var out = [];
+        this.walk(new TreeWalker(function (node) {
+            if (node instanceof AST_Symbol) {
+                out.push(node);
+            }
+        }));
+        return out;
+    }
+});
+
+var AST_PrefixedTemplateString = DEFNODE("PrefixedTemplateString", "template_string prefix", {
+    $documentation: "A templatestring with a prefix, such as String.raw`foobarbaz`",
+    $propdoc: {
+        template_string: "[AST_TemplateString] The template string",
+        prefix: "[AST_Node] The prefix, which will get called."
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function () {
+            this.prefix._walk(visitor);
+            this.template_string._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.template_string);
+        push(this.prefix);
+    },
+});
+
+var AST_TemplateString = DEFNODE("TemplateString", "segments", {
+    $documentation: "A template string literal",
+    $propdoc: {
+        segments: "[AST_Node*] One or more segments, starting with AST_TemplateSegment. AST_Node may follow AST_TemplateSegment, but each AST_Node must be followed by AST_TemplateSegment."
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.segments.forEach(function(seg) {
+                seg._walk(visitor);
+            });
+        });
+    },
+    _children_backwards(push) {
+        let i = this.segments.length;
+        while (i--) push(this.segments[i]);
+    }
+});
+
+var AST_TemplateSegment = DEFNODE("TemplateSegment", "value raw", {
+    $documentation: "A segment of a template string literal",
+    $propdoc: {
+        value: "Content of the segment",
+        raw: "Raw source of the segment",
+    }
+});
+
+/* -----[ JUMPS ]----- */
+
+var AST_Jump = DEFNODE("Jump", null, {
+    $documentation: "Base class for “jumps” (for now that's `return`, `throw`, `break` and `continue`)"
+}, AST_Statement);
+
+var AST_Exit = DEFNODE("Exit", "value", {
+    $documentation: "Base class for “exits” (`return` and `throw`)",
+    $propdoc: {
+        value: "[AST_Node?] the value returned or thrown by this statement; could be null for AST_Return"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, this.value && function() {
+            this.value._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        if (this.value) push(this.value);
+    },
+}, AST_Jump);
+
+var AST_Return = DEFNODE("Return", null, {
+    $documentation: "A `return` statement"
+}, AST_Exit);
+
+var AST_Throw = DEFNODE("Throw", null, {
+    $documentation: "A `throw` statement"
+}, AST_Exit);
+
+var AST_LoopControl = DEFNODE("LoopControl", "label", {
+    $documentation: "Base class for loop control statements (`break` and `continue`)",
+    $propdoc: {
+        label: "[AST_LabelRef?] the label, or null if none",
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, this.label && function() {
+            this.label._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        if (this.label) push(this.label);
+    },
+}, AST_Jump);
+
+var AST_Break = DEFNODE("Break", null, {
+    $documentation: "A `break` statement"
+}, AST_LoopControl);
+
+var AST_Continue = DEFNODE("Continue", null, {
+    $documentation: "A `continue` statement"
+}, AST_LoopControl);
+
+var AST_Await = DEFNODE("Await", "expression", {
+    $documentation: "An `await` statement",
+    $propdoc: {
+        expression: "[AST_Node] the mandatory expression being awaited",
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.expression._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.expression);
+    },
+});
+
+var AST_Yield = DEFNODE("Yield", "expression is_star", {
+    $documentation: "A `yield` statement",
+    $propdoc: {
+        expression: "[AST_Node?] the value returned or thrown by this statement; could be null (representing undefined) but only when is_star is set to false",
+        is_star: "[Boolean] Whether this is a yield or yield* statement"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, this.expression && function() {
+            this.expression._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        if (this.expression) push(this.expression);
+    }
+});
+
+/* -----[ IF ]----- */
+
+var AST_If = DEFNODE("If", "condition alternative", {
+    $documentation: "A `if` statement",
+    $propdoc: {
+        condition: "[AST_Node] the `if` condition",
+        alternative: "[AST_Statement?] the `else` part, or null if not present"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.condition._walk(visitor);
+            this.body._walk(visitor);
+            if (this.alternative) this.alternative._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        if (this.alternative) {
+            push(this.alternative);
+        }
+        push(this.body);
+        push(this.condition);
+    }
+}, AST_StatementWithBody);
+
+/* -----[ SWITCH ]----- */
+
+var AST_Switch = DEFNODE("Switch", "expression", {
+    $documentation: "A `switch` statement",
+    $propdoc: {
+        expression: "[AST_Node] the `switch` “discriminant”"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.expression._walk(visitor);
+            walk_body(this, visitor);
+        });
+    },
+    _children_backwards(push) {
+        let i = this.body.length;
+        while (i--) push(this.body[i]);
+        push(this.expression);
+    }
+}, AST_Block);
+
+var AST_SwitchBranch = DEFNODE("SwitchBranch", null, {
+    $documentation: "Base class for `switch` branches",
+}, AST_Block);
+
+var AST_Default = DEFNODE("Default", null, {
+    $documentation: "A `default` switch branch",
+}, AST_SwitchBranch);
+
+var AST_Case = DEFNODE("Case", "expression", {
+    $documentation: "A `case` switch branch",
+    $propdoc: {
+        expression: "[AST_Node] the `case` expression"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.expression._walk(visitor);
+            walk_body(this, visitor);
+        });
+    },
+    _children_backwards(push) {
+        let i = this.body.length;
+        while (i--) push(this.body[i]);
+        push(this.expression);
+    },
+}, AST_SwitchBranch);
+
+/* -----[ EXCEPTIONS ]----- */
+
+var AST_Try = DEFNODE("Try", "bcatch bfinally", {
+    $documentation: "A `try` statement",
+    $propdoc: {
+        bcatch: "[AST_Catch?] the catch block, or null if not present",
+        bfinally: "[AST_Finally?] the finally block, or null if not present"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            walk_body(this, visitor);
+            if (this.bcatch) this.bcatch._walk(visitor);
+            if (this.bfinally) this.bfinally._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        if (this.bfinally) push(this.bfinally);
+        if (this.bcatch) push(this.bcatch);
+        let i = this.body.length;
+        while (i--) push(this.body[i]);
+    },
+}, AST_Block);
+
+var AST_Catch = DEFNODE("Catch", "argname", {
+    $documentation: "A `catch` node; only makes sense as part of a `try` statement",
+    $propdoc: {
+        argname: "[AST_SymbolCatch|AST_Destructuring|AST_Expansion|AST_DefaultAssign] symbol for the exception"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            if (this.argname) this.argname._walk(visitor);
+            walk_body(this, visitor);
+        });
+    },
+    _children_backwards(push) {
+        let i = this.body.length;
+        while (i--) push(this.body[i]);
+        if (this.argname) push(this.argname);
+    },
+}, AST_Block);
+
+var AST_Finally = DEFNODE("Finally", null, {
+    $documentation: "A `finally` node; only makes sense as part of a `try` statement"
+}, AST_Block);
+
+/* -----[ VAR/CONST ]----- */
+
+var AST_Definitions = DEFNODE("Definitions", "definitions", {
+    $documentation: "Base class for `var` or `const` nodes (variable declarations/initializations)",
+    $propdoc: {
+        definitions: "[AST_VarDef*] array of variable definitions"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            var definitions = this.definitions;
+            for (var i = 0, len = definitions.length; i < len; i++) {
+                definitions[i]._walk(visitor);
+            }
+        });
+    },
+    _children_backwards(push) {
+        let i = this.definitions.length;
+        while (i--) push(this.definitions[i]);
+    },
+}, AST_Statement);
+
+var AST_Var = DEFNODE("Var", null, {
+    $documentation: "A `var` statement"
+}, AST_Definitions);
+
+var AST_Let = DEFNODE("Let", null, {
+    $documentation: "A `let` statement"
+}, AST_Definitions);
+
+var AST_Const = DEFNODE("Const", null, {
+    $documentation: "A `const` statement"
+}, AST_Definitions);
+
+var AST_VarDef = DEFNODE("VarDef", "name value", {
+    $documentation: "A variable declaration; only appears in a AST_Definitions node",
+    $propdoc: {
+        name: "[AST_Destructuring|AST_SymbolConst|AST_SymbolLet|AST_SymbolVar] name of the variable",
+        value: "[AST_Node?] initializer, or null of there's no initializer"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.name._walk(visitor);
+            if (this.value) this.value._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        if (this.value) push(this.value);
+        push(this.name);
+    },
+});
+
+var AST_NameMapping = DEFNODE("NameMapping", "foreign_name name", {
+    $documentation: "The part of the export/import statement that declare names from a module.",
+    $propdoc: {
+        foreign_name: "[AST_SymbolExportForeign|AST_SymbolImportForeign] The name being exported/imported (as specified in the module)",
+        name: "[AST_SymbolExport|AST_SymbolImport] The name as it is visible to this module."
+    },
+    _walk: function (visitor) {
+        return visitor._visit(this, function() {
+            this.foreign_name._walk(visitor);
+            this.name._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.name);
+        push(this.foreign_name);
+    },
+});
+
+var AST_Import = DEFNODE("Import", "imported_name imported_names module_name", {
+    $documentation: "An `import` statement",
+    $propdoc: {
+        imported_name: "[AST_SymbolImport] The name of the variable holding the module's default export.",
+        imported_names: "[AST_NameMapping*] The names of non-default imported variables",
+        module_name: "[AST_String] String literal describing where this module came from",
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            if (this.imported_name) {
+                this.imported_name._walk(visitor);
+            }
+            if (this.imported_names) {
+                this.imported_names.forEach(function(name_import) {
+                    name_import._walk(visitor);
+                });
+            }
+            this.module_name._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.module_name);
+        if (this.imported_names) {
+            let i = this.imported_names.length;
+            while (i--) push(this.imported_names[i]);
+        }
+        if (this.imported_name) push(this.imported_name);
+    },
+});
+
+var AST_ImportMeta = DEFNODE("ImportMeta", null, {
+    $documentation: "A reference to import.meta",
+});
+
+var AST_Export = DEFNODE("Export", "exported_definition exported_value is_default exported_names module_name", {
+    $documentation: "An `export` statement",
+    $propdoc: {
+        exported_definition: "[AST_Defun|AST_Definitions|AST_DefClass?] An exported definition",
+        exported_value: "[AST_Node?] An exported value",
+        exported_names: "[AST_NameMapping*?] List of exported names",
+        module_name: "[AST_String?] Name of the file to load exports from",
+        is_default: "[Boolean] Whether this is the default exported value of this module"
+    },
+    _walk: function (visitor) {
+        return visitor._visit(this, function () {
+            if (this.exported_definition) {
+                this.exported_definition._walk(visitor);
+            }
+            if (this.exported_value) {
+                this.exported_value._walk(visitor);
+            }
+            if (this.exported_names) {
+                this.exported_names.forEach(function(name_export) {
+                    name_export._walk(visitor);
+                });
+            }
+            if (this.module_name) {
+                this.module_name._walk(visitor);
+            }
+        });
+    },
+    _children_backwards(push) {
+        if (this.module_name) push(this.module_name);
+        if (this.exported_names) {
+            let i = this.exported_names.length;
+            while (i--) push(this.exported_names[i]);
+        }
+        if (this.exported_value) push(this.exported_value);
+        if (this.exported_definition) push(this.exported_definition);
+    }
+}, AST_Statement);
+
+/* -----[ OTHER ]----- */
+
+var AST_Call = DEFNODE("Call", "expression args optional _annotations", {
+    $documentation: "A function call expression",
+    $propdoc: {
+        expression: "[AST_Node] expression to invoke as function",
+        args: "[AST_Node*] array of arguments",
+        optional: "[boolean] whether this is an optional call (IE ?.() )",
+        _annotations: "[number] bitfield containing information about the call"
+    },
+    initialize() {
+        if (this._annotations == null) this._annotations = 0;
+    },
+    _walk(visitor) {
+        return visitor._visit(this, function() {
+            var args = this.args;
+            for (var i = 0, len = args.length; i < len; i++) {
+                args[i]._walk(visitor);
+            }
+            this.expression._walk(visitor);  // TODO why do we need to crawl this last?
+        });
+    },
+    _children_backwards(push) {
+        let i = this.args.length;
+        while (i--) push(this.args[i]);
+        push(this.expression);
+    },
+});
+
+var AST_New = DEFNODE("New", null, {
+    $documentation: "An object instantiation.  Derives from a function call since it has exactly the same properties"
+}, AST_Call);
+
+var AST_Sequence = DEFNODE("Sequence", "expressions", {
+    $documentation: "A sequence expression (comma-separated expressions)",
+    $propdoc: {
+        expressions: "[AST_Node*] array of expressions (at least two)"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.expressions.forEach(function(node) {
+                node._walk(visitor);
+            });
+        });
+    },
+    _children_backwards(push) {
+        let i = this.expressions.length;
+        while (i--) push(this.expressions[i]);
+    },
+});
+
+var AST_PropAccess = DEFNODE("PropAccess", "expression property optional", {
+    $documentation: "Base class for property access expressions, i.e. `a.foo` or `a[\"foo\"]`",
+    $propdoc: {
+        expression: "[AST_Node] the “container” expression",
+        property: "[AST_Node|string] the property to access.  For AST_Dot this is always a plain string, while for AST_Sub it's an arbitrary AST_Node",
+
+        optional: "[boolean] whether this is an optional property access (IE ?.)"
+    }
+});
+
+var AST_Dot = DEFNODE("Dot", "quote", {
+    $documentation: "A dotted property access expression",
+    $propdoc: {
+        quote: "[string] the original quote character when transformed from AST_Sub",
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.expression._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.expression);
+    },
+}, AST_PropAccess);
+
+var AST_Sub = DEFNODE("Sub", null, {
+    $documentation: "Index-style property access, i.e. `a[\"foo\"]`",
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.expression._walk(visitor);
+            this.property._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.property);
+        push(this.expression);
+    },
+}, AST_PropAccess);
+
+var AST_Chain = DEFNODE("Chain", "expression", {
+    $documentation: "A chain expression like a?.b?.(c)?.[d]",
+    $propdoc: {
+        expression: "[AST_Call|AST_Dot|AST_Sub] chain element."
+    },
+    _walk: function (visitor) {
+        return visitor._visit(this, function() {
+            this.expression._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.expression);
+    },
+});
+
+var AST_Unary = DEFNODE("Unary", "operator expression", {
+    $documentation: "Base class for unary expressions",
+    $propdoc: {
+        operator: "[string] the operator",
+        expression: "[AST_Node] expression that this unary operator applies to"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.expression._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.expression);
+    },
+});
+
+var AST_UnaryPrefix = DEFNODE("UnaryPrefix", null, {
+    $documentation: "Unary prefix expression, i.e. `typeof i` or `++i`"
+}, AST_Unary);
+
+var AST_UnaryPostfix = DEFNODE("UnaryPostfix", null, {
+    $documentation: "Unary postfix expression, i.e. `i++`"
+}, AST_Unary);
+
+var AST_Binary = DEFNODE("Binary", "operator left right", {
+    $documentation: "Binary expression, i.e. `a + b`",
+    $propdoc: {
+        left: "[AST_Node] left-hand side expression",
+        operator: "[string] the operator",
+        right: "[AST_Node] right-hand side expression"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.left._walk(visitor);
+            this.right._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.right);
+        push(this.left);
+    },
+});
+
+var AST_Conditional = DEFNODE("Conditional", "condition consequent alternative", {
+    $documentation: "Conditional expression using the ternary operator, i.e. `a ? b : c`",
+    $propdoc: {
+        condition: "[AST_Node]",
+        consequent: "[AST_Node]",
+        alternative: "[AST_Node]"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            this.condition._walk(visitor);
+            this.consequent._walk(visitor);
+            this.alternative._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.alternative);
+        push(this.consequent);
+        push(this.condition);
+    },
+});
+
+var AST_Assign = DEFNODE("Assign", "logical", {
+    $documentation: "An assignment expression — `a = b + 5`",
+    $propdoc: {
+        logical: "Whether it's a logical assignment"
+    }
+}, AST_Binary);
+
+var AST_DefaultAssign = DEFNODE("DefaultAssign", null, {
+    $documentation: "A default assignment expression like in `(a = 3) => a`"
+}, AST_Binary);
+
+/* -----[ LITERALS ]----- */
+
+var AST_Array = DEFNODE("Array", "elements", {
+    $documentation: "An array literal",
+    $propdoc: {
+        elements: "[AST_Node*] array of elements"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            var elements = this.elements;
+            for (var i = 0, len = elements.length; i < len; i++) {
+                elements[i]._walk(visitor);
+            }
+        });
+    },
+    _children_backwards(push) {
+        let i = this.elements.length;
+        while (i--) push(this.elements[i]);
+    },
+});
+
+var AST_Object = DEFNODE("Object", "properties", {
+    $documentation: "An object literal",
+    $propdoc: {
+        properties: "[AST_ObjectProperty*] array of properties"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            var properties = this.properties;
+            for (var i = 0, len = properties.length; i < len; i++) {
+                properties[i]._walk(visitor);
+            }
+        });
+    },
+    _children_backwards(push) {
+        let i = this.properties.length;
+        while (i--) push(this.properties[i]);
+    },
+});
+
+var AST_ObjectProperty = DEFNODE("ObjectProperty", "key value", {
+    $documentation: "Base class for literal object properties",
+    $propdoc: {
+        key: "[string|AST_Node] property name. For ObjectKeyVal this is a string. For getters, setters and computed property this is an AST_Node.",
+        value: "[AST_Node] property value.  For getters and setters this is an AST_Accessor."
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            if (this.key instanceof AST_Node)
+                this.key._walk(visitor);
+            this.value._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        push(this.value);
+        if (this.key instanceof AST_Node) push(this.key);
+    }
+});
+
+var AST_ObjectKeyVal = DEFNODE("ObjectKeyVal", "quote", {
+    $documentation: "A key: value object property",
+    $propdoc: {
+        quote: "[string] the original quote character"
+    },
+    computed_key() {
+        return this.key instanceof AST_Node;
+    }
+}, AST_ObjectProperty);
+
+var AST_ObjectSetter = DEFNODE("ObjectSetter", "quote static", {
+    $propdoc: {
+        quote: "[string|undefined] the original quote character, if any",
+        static: "[boolean] whether this is a static setter (classes only)"
+    },
+    $documentation: "An object setter property",
+    computed_key() {
+        return !(this.key instanceof AST_SymbolMethod);
+    }
+}, AST_ObjectProperty);
+
+var AST_ObjectGetter = DEFNODE("ObjectGetter", "quote static", {
+    $propdoc: {
+        quote: "[string|undefined] the original quote character, if any",
+        static: "[boolean] whether this is a static getter (classes only)"
+    },
+    $documentation: "An object getter property",
+    computed_key() {
+        return !(this.key instanceof AST_SymbolMethod);
+    }
+}, AST_ObjectProperty);
+
+var AST_ConciseMethod = DEFNODE("ConciseMethod", "quote static is_generator async", {
+    $propdoc: {
+        quote: "[string|undefined] the original quote character, if any",
+        static: "[boolean] is this method static (classes only)",
+        is_generator: "[boolean] is this a generator method",
+        async: "[boolean] is this method async",
+    },
+    $documentation: "An ES6 concise method inside an object or class",
+    computed_key() {
+        return !(this.key instanceof AST_SymbolMethod);
+    }
+}, AST_ObjectProperty);
+
+var AST_Class = DEFNODE("Class", "name extends properties", {
+    $propdoc: {
+        name: "[AST_SymbolClass|AST_SymbolDefClass?] optional class name.",
+        extends: "[AST_Node]? optional parent class",
+        properties: "[AST_ObjectProperty*] array of properties"
+    },
+    $documentation: "An ES6 class",
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            if (this.name) {
+                this.name._walk(visitor);
+            }
+            if (this.extends) {
+                this.extends._walk(visitor);
+            }
+            this.properties.forEach((prop) => prop._walk(visitor));
+        });
+    },
+    _children_backwards(push) {
+        let i = this.properties.length;
+        while (i--) push(this.properties[i]);
+        if (this.extends) push(this.extends);
+        if (this.name) push(this.name);
+    },
+}, AST_Scope /* TODO a class might have a scope but it's not a scope */);
+
+var AST_ClassProperty = DEFNODE("ClassProperty", "static quote", {
+    $documentation: "A class property",
+    $propdoc: {
+        static: "[boolean] whether this is a static key",
+        quote: "[string] which quote is being used"
+    },
+    _walk: function(visitor) {
+        return visitor._visit(this, function() {
+            if (this.key instanceof AST_Node)
+                this.key._walk(visitor);
+            if (this.value instanceof AST_Node)
+                this.value._walk(visitor);
+        });
+    },
+    _children_backwards(push) {
+        if (this.value instanceof AST_Node) push(this.value);
+        if (this.key instanceof AST_Node) push(this.key);
+    },
+    computed_key() {
+        return !(this.key instanceof AST_SymbolClassProperty);
+    }
+}, AST_ObjectProperty);
+
+var AST_DefClass = DEFNODE("DefClass", null, {
+    $documentation: "A class definition",
+}, AST_Class);
+
+var AST_ClassExpression = DEFNODE("ClassExpression", null, {
+    $documentation: "A class expression."
+}, AST_Class);
+
+var AST_Symbol = DEFNODE("Symbol", "scope name thedef", {
+    $propdoc: {
+        name: "[string] name of this symbol",
+        scope: "[AST_Scope/S] the current scope (not necessarily the definition scope)",
+        thedef: "[SymbolDef/S] the definition of this symbol"
+    },
+    $documentation: "Base class for all symbols"
+});
+
+var AST_NewTarget = DEFNODE("NewTarget", null, {
+    $documentation: "A reference to new.target"
+});
+
+var AST_SymbolDeclaration = DEFNODE("SymbolDeclaration", "init", {
+    $documentation: "A declaration symbol (symbol in var/const, function name or argument, symbol in catch)",
+}, AST_Symbol);
+
+var AST_SymbolVar = DEFNODE("SymbolVar", null, {
+    $documentation: "Symbol defining a variable",
+}, AST_SymbolDeclaration);
+
+var AST_SymbolBlockDeclaration = DEFNODE("SymbolBlockDeclaration", null, {
+    $documentation: "Base class for block-scoped declaration symbols"
+}, AST_SymbolDeclaration);
+
+var AST_SymbolConst = DEFNODE("SymbolConst", null, {
+    $documentation: "A constant declaration"
+}, AST_SymbolBlockDeclaration);
+
+var AST_SymbolLet = DEFNODE("SymbolLet", null, {
+    $documentation: "A block-scoped `let` declaration"
+}, AST_SymbolBlockDeclaration);
+
+var AST_SymbolFunarg = DEFNODE("SymbolFunarg", null, {
+    $documentation: "Symbol naming a function argument",
+}, AST_SymbolVar);
+
+var AST_SymbolDefun = DEFNODE("SymbolDefun", null, {
+    $documentation: "Symbol defining a function",
+}, AST_SymbolDeclaration);
+
+var AST_SymbolMethod = DEFNODE("SymbolMethod", null, {
+    $documentation: "Symbol in an object defining a method",
+}, AST_Symbol);
+
+var AST_SymbolClassProperty = DEFNODE("SymbolClassProperty", null, {
+    $documentation: "Symbol for a class property",
+}, AST_Symbol);
+
+var AST_SymbolLambda = DEFNODE("SymbolLambda", null, {
+    $documentation: "Symbol naming a function expression",
+}, AST_SymbolDeclaration);
+
+var AST_SymbolDefClass = DEFNODE("SymbolDefClass", null, {
+    $documentation: "Symbol naming a class's name in a class declaration. Lexically scoped to its containing scope, and accessible within the class."
+}, AST_SymbolBlockDeclaration);
+
+var AST_SymbolClass = DEFNODE("SymbolClass", null, {
+    $documentation: "Symbol naming a class's name. Lexically scoped to the class."
+}, AST_SymbolDeclaration);
+
+var AST_SymbolCatch = DEFNODE("SymbolCatch", null, {
+    $documentation: "Symbol naming the exception in catch",
+}, AST_SymbolBlockDeclaration);
+
+var AST_SymbolImport = DEFNODE("SymbolImport", null, {
+    $documentation: "Symbol referring to an imported name",
+}, AST_SymbolBlockDeclaration);
+
+var AST_SymbolImportForeign = DEFNODE("SymbolImportForeign", null, {
+    $documentation: "A symbol imported from a module, but it is defined in the other module, and its real name is irrelevant for this module's purposes",
+}, AST_Symbol);
+
+var AST_Label = DEFNODE("Label", "references", {
+    $documentation: "Symbol naming a label (declaration)",
+    $propdoc: {
+        references: "[AST_LoopControl*] a list of nodes referring to this label"
+    },
+    initialize: function() {
+        this.references = [];
+        this.thedef = this;
+    }
+}, AST_Symbol);
+
+var AST_SymbolRef = DEFNODE("SymbolRef", null, {
+    $documentation: "Reference to some symbol (not definition/declaration)",
+}, AST_Symbol);
+
+var AST_SymbolExport = DEFNODE("SymbolExport", null, {
+    $documentation: "Symbol referring to a name to export",
+}, AST_SymbolRef);
+
+var AST_SymbolExportForeign = DEFNODE("SymbolExportForeign", null, {
+    $documentation: "A symbol exported from this module, but it is used in the other module, and its real name is irrelevant for this module's purposes",
+}, AST_Symbol);
+
+var AST_LabelRef = DEFNODE("LabelRef", null, {
+    $documentation: "Reference to a label symbol",
+}, AST_Symbol);
+
+var AST_This = DEFNODE("This", null, {
+    $documentation: "The `this` symbol",
+}, AST_Symbol);
+
+var AST_Super = DEFNODE("Super", null, {
+    $documentation: "The `super` symbol",
+}, AST_This);
+
+var AST_Constant = DEFNODE("Constant", null, {
+    $documentation: "Base class for all constants",
+    getValue: function() {
+        return this.value;
+    }
+});
+
+var AST_String = DEFNODE("String", "value quote", {
+    $documentation: "A string literal",
+    $propdoc: {
+        value: "[string] the contents of this string",
+        quote: "[string] the original quote character"
+    }
+}, AST_Constant);
+
+var AST_Number = DEFNODE("Number", "value raw", {
+    $documentation: "A number literal",
+    $propdoc: {
+        value: "[number] the numeric value",
+        raw: "[string] numeric value as string"
+    }
+}, AST_Constant);
+
+var AST_BigInt = DEFNODE("BigInt", "value", {
+    $documentation: "A big int literal",
+    $propdoc: {
+        value: "[string] big int value"
+    }
+}, AST_Constant);
+
+var AST_RegExp = DEFNODE("RegExp", "value", {
+    $documentation: "A regexp literal",
+    $propdoc: {
+        value: "[RegExp] the actual regexp",
+    }
+}, AST_Constant);
+
+var AST_Atom = DEFNODE("Atom", null, {
+    $documentation: "Base class for atoms",
+}, AST_Constant);
+
+var AST_Null = DEFNODE("Null", null, {
+    $documentation: "The `null` atom",
+    value: null
+}, AST_Atom);
+
+var AST_NaN = DEFNODE("NaN", null, {
+    $documentation: "The impossible value",
+    value: 0/0
+}, AST_Atom);
+
+var AST_Undefined = DEFNODE("Undefined", null, {
+    $documentation: "The `undefined` value",
+    value: (function() {}())
+}, AST_Atom);
+
+var AST_Hole = DEFNODE("Hole", null, {
+    $documentation: "A hole in an array",
+    value: (function() {}())
+}, AST_Atom);
+
+var AST_Infinity = DEFNODE("Infinity", null, {
+    $documentation: "The `Infinity` value",
+    value: 1/0
+}, AST_Atom);
+
+var AST_Boolean = DEFNODE("Boolean", null, {
+    $documentation: "Base class for booleans",
+}, AST_Atom);
+
+var AST_False = DEFNODE("False", null, {
+    $documentation: "The `false` atom",
+    value: false
+}, AST_Boolean);
+
+var AST_True = DEFNODE("True", null, {
+    $documentation: "The `true` atom",
+    value: true
+}, AST_Boolean);
+
+/* -----[ Walk function ]---- */
+
+/**
+ * Walk nodes in depth-first search fashion.
+ * Callback can return `walk_abort` symbol to stop iteration.
+ * It can also return `true` to stop iteration just for child nodes.
+ * Iteration can be stopped and continued by passing the `to_visit` argument,
+ * which is given to the callback in the second argument.
+ **/
+function walk(node, cb, to_visit = [node]) {
+    const push = to_visit.push.bind(to_visit);
+    while (to_visit.length) {
+        const node = to_visit.pop();
+        const ret = cb(node, to_visit);
+
+        if (ret) {
+            if (ret === walk_abort) return true;
+            continue;
+        }
+
+        node._children_backwards(push);
+    }
+    return false;
+}
+
+function walk_parent(node, cb, initial_stack) {
+    const to_visit = [node];
+    const push = to_visit.push.bind(to_visit);
+    const stack = initial_stack ? initial_stack.slice() : [];
+    const parent_pop_indices = [];
+
+    let current;
+
+    const info = {
+        parent: (n = 0) => {
+            if (n === -1) {
+                return current;
+            }
+
+            // [ p1 p0 ] [ 1 0 ]
+            if (initial_stack && n >= stack.length) {
+                n -= stack.length;
+                return initial_stack[
+                    initial_stack.length - (n + 1)
+                ];
+            }
+
+            return stack[stack.length - (1 + n)];
+        },
+    };
+
+    while (to_visit.length) {
+        current = to_visit.pop();
+
+        while (
+            parent_pop_indices.length &&
+            to_visit.length == parent_pop_indices[parent_pop_indices.length - 1]
+        ) {
+            stack.pop();
+            parent_pop_indices.pop();
+        }
+
+        const ret = cb(current, info);
+
+        if (ret) {
+            if (ret === walk_abort) return true;
+            continue;
+        }
+
+        const visit_length = to_visit.length;
+
+        current._children_backwards(push);
+
+        // Push only if we're going to traverse the children
+        if (to_visit.length > visit_length) {
+            stack.push(current);
+            parent_pop_indices.push(visit_length - 1);
+        }
+    }
+
+    return false;
+}
+
+const walk_abort = Symbol("abort walk");
+
+/* -----[ TreeWalker ]----- */
+
+class TreeWalker {
+    constructor(callback) {
+        this.visit = callback;
+        this.stack = [];
+        this.directives = Object.create(null);
+    }
+
+    _visit(node, descend) {
+        this.push(node);
+        var ret = this.visit(node, descend ? function() {
+            descend.call(node);
+        } : noop);
+        if (!ret && descend) {
+            descend.call(node);
+        }
+        this.pop();
+        return ret;
+    }
+
+    parent(n) {
+        return this.stack[this.stack.length - 2 - (n || 0)];
+    }
+
+    push(node) {
+        if (node instanceof AST_Lambda) {
+            this.directives = Object.create(this.directives);
+        } else if (node instanceof AST_Directive && !this.directives[node.value]) {
+            this.directives[node.value] = node;
+        } else if (node instanceof AST_Class) {
+            this.directives = Object.create(this.directives);
+            if (!this.directives["use strict"]) {
+                this.directives["use strict"] = node;
+            }
+        }
+        this.stack.push(node);
+    }
+
+    pop() {
+        var node = this.stack.pop();
+        if (node instanceof AST_Lambda || node instanceof AST_Class) {
+            this.directives = Object.getPrototypeOf(this.directives);
+        }
+    }
+
+    self() {
+        return this.stack[this.stack.length - 1];
+    }
+
+    find_parent(type) {
+        var stack = this.stack;
+        for (var i = stack.length; --i >= 0;) {
+            var x = stack[i];
+            if (x instanceof type) return x;
+        }
+    }
+
+    has_directive(type) {
+        var dir = this.directives[type];
+        if (dir) return dir;
+        var node = this.stack[this.stack.length - 1];
+        if (node instanceof AST_Scope && node.body) {
+            for (var i = 0; i < node.body.length; ++i) {
+                var st = node.body[i];
+                if (!(st instanceof AST_Directive)) break;
+                if (st.value == type) return st;
+            }
+        }
+    }
+
+    loopcontrol_target(node) {
+        var stack = this.stack;
+        if (node.label) for (var i = stack.length; --i >= 0;) {
+            var x = stack[i];
+            if (x instanceof AST_LabeledStatement && x.label.name == node.label.name)
+                return x.body;
+        } else for (var i = stack.length; --i >= 0;) {
+            var x = stack[i];
+            if (x instanceof AST_IterationStatement
+                || node instanceof AST_Break && x instanceof AST_Switch)
+                return x;
+        }
+    }
+}
+
+// Tree transformer helpers.
+class TreeTransformer extends TreeWalker {
+    constructor(before, after) {
+        super();
+        this.before = before;
+        this.after = after;
+    }
+}
+
+const _PURE     = 0b00000001;
+const _INLINE   = 0b00000010;
+const _NOINLINE = 0b00000100;
+
+export {
+    AST_Accessor,
+    AST_Array,
+    AST_Arrow,
+    AST_Assign,
+    AST_Atom,
+    AST_Await,
+    AST_BigInt,
+    AST_Binary,
+    AST_Block,
+    AST_BlockStatement,
+    AST_Boolean,
+    AST_Break,
+    AST_Call,
+    AST_Case,
+    AST_Catch,
+    AST_Chain,
+    AST_Class,
+    AST_ClassExpression,
+    AST_ClassProperty,
+    AST_ConciseMethod,
+    AST_Conditional,
+    AST_Const,
+    AST_Constant,
+    AST_Continue,
+    AST_Debugger,
+    AST_Default,
+    AST_DefaultAssign,
+    AST_DefClass,
+    AST_Definitions,
+    AST_Defun,
+    AST_Destructuring,
+    AST_Directive,
+    AST_Do,
+    AST_Dot,
+    AST_DWLoop,
+    AST_EmptyStatement,
+    AST_Exit,
+    AST_Expansion,
+    AST_Export,
+    AST_False,
+    AST_Finally,
+    AST_For,
+    AST_ForIn,
+    AST_ForOf,
+    AST_Function,
+    AST_Hole,
+    AST_If,
+    AST_Import,
+    AST_ImportMeta,
+    AST_Infinity,
+    AST_IterationStatement,
+    AST_Jump,
+    AST_Label,
+    AST_LabeledStatement,
+    AST_LabelRef,
+    AST_Lambda,
+    AST_Let,
+    AST_LoopControl,
+    AST_NameMapping,
+    AST_NaN,
+    AST_New,
+    AST_NewTarget,
+    AST_Node,
+    AST_Null,
+    AST_Number,
+    AST_Object,
+    AST_ObjectGetter,
+    AST_ObjectKeyVal,
+    AST_ObjectProperty,
+    AST_ObjectSetter,
+    AST_PrefixedTemplateString,
+    AST_PropAccess,
+    AST_RegExp,
+    AST_Return,
+    AST_Scope,
+    AST_Sequence,
+    AST_SimpleStatement,
+    AST_Statement,
+    AST_StatementWithBody,
+    AST_String,
+    AST_Sub,
+    AST_Super,
+    AST_Switch,
+    AST_SwitchBranch,
+    AST_Symbol,
+    AST_SymbolBlockDeclaration,
+    AST_SymbolCatch,
+    AST_SymbolClass,
+    AST_SymbolClassProperty,
+    AST_SymbolConst,
+    AST_SymbolDeclaration,
+    AST_SymbolDefClass,
+    AST_SymbolDefun,
+    AST_SymbolExport,
+    AST_SymbolExportForeign,
+    AST_SymbolFunarg,
+    AST_SymbolImport,
+    AST_SymbolImportForeign,
+    AST_SymbolLambda,
+    AST_SymbolLet,
+    AST_SymbolMethod,
+    AST_SymbolRef,
+    AST_SymbolVar,
+    AST_TemplateSegment,
+    AST_TemplateString,
+    AST_This,
+    AST_Throw,
+    AST_Token,
+    AST_Toplevel,
+    AST_True,
+    AST_Try,
+    AST_Unary,
+    AST_UnaryPostfix,
+    AST_UnaryPrefix,
+    AST_Undefined,
+    AST_Var,
+    AST_VarDef,
+    AST_While,
+    AST_With,
+    AST_Yield,
+
+    // Walkers
+    TreeTransformer,
+    TreeWalker,
+    walk,
+    walk_abort,
+    walk_body,
+    walk_parent,
+
+    // annotations
+    _INLINE,
+    _NOINLINE,
+    _PURE,
+};