Use default params when --destructure-named-params + fix renaming of reserved destructured params

lib/src/js/nodes.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of js_ast;
 
 abstract class NodeVisitor<T> {
   T visitProgram(Program node);
 
   T visitBlock(Block node);
@@ skipping 74 matching lines @@
   T visitInterpolatedLiteral(InterpolatedLiteral node);
   T visitInterpolatedParameter(InterpolatedParameter node);
   T visitInterpolatedSelector(InterpolatedSelector node);
   T visitInterpolatedStatement(InterpolatedStatement node);
   T visitInterpolatedMethod(InterpolatedMethod node);
   T visitInterpolatedIdentifier(InterpolatedIdentifier node);
 
   T visitArrayBindingPattern(ArrayBindingPattern node);
   T visitObjectBindingPattern(ObjectBindingPattern node);
   T visitDestructuredVariable(DestructuredVariable node);
+  T visitSimpleBindingPattern(SimpleBindingPattern node);
 }
 
 class BaseVisitor<T> implements NodeVisitor<T> {
   T visitNode(Node node) {
     node.visitChildren(this);
     return null;
   }
 
   T visitProgram(Program node) => visitNode(node);
 
@@ skipping 109 matching lines @@
 
   T visitAwait(Await node) => visitExpression(node);
   T visitDartYield(DartYield node) => visitStatement(node);
 
   T visitBindingPattern(BindingPattern node) => visitNode(node);
   T visitArrayBindingPattern(ArrayBindingPattern node)
       => visitBindingPattern(node);
   T visitObjectBindingPattern(ObjectBindingPattern node)
       => visitBindingPattern(node);
   T visitDestructuredVariable(DestructuredVariable node) => visitNode(node);
+  T visitSimpleBindingPattern(SimpleBindingPattern node) => visitNode(node);
 }
 
 abstract class Node {
   /// Sets the source location of this node. For performance reasons, we allow
   /// setting this after construction.
   Object sourceInformation;
 
   ClosureAnnotation _closureAnnotation;
   /// Closure annotation of this node.
   ClosureAnnotation get closureAnnotation => _closureAnnotation;
@@ skipping 536 matching lines @@
   accept(NodeVisitor visitor) => visitor.visitVariableInitialization(this);
 
   VariableInitialization _clone() =>
       new VariableInitialization(declaration, value);
 }
 
 abstract class VariableBinding extends Expression {
 }
 
 class DestructuredVariable extends Expression implements Parameter {
-  final Identifier name;
+  /// [LiteralString] or [Identifier].
+  final Expression name;
   final BindingPattern structure;
   final Expression defaultValue;
   DestructuredVariable({this.name, this.structure, this.defaultValue}) {
     assert(name != null || structure != null);
   }
 
   accept(NodeVisitor visitor) => visitor.visitDestructuredVariable(this);
   void visitChildren(NodeVisitor visitor) {
     name?.accept(visitor);
     structure?.accept(visitor);
     defaultValue?.accept(visitor);
   }
 
   /// Avoid parenthesis when pretty-printing.
   @override int get precedenceLevel => PRIMARY;
   @override Node _clone() =>
       new DestructuredVariable(
           name: name, structure: structure, defaultValue: defaultValue);
 }
 
 abstract class BindingPattern extends Expression implements VariableBinding {
   final List<DestructuredVariable> variables;
   BindingPattern(this.variables);
 
   void visitChildren(NodeVisitor visitor) {
     for (DestructuredVariable v in variables) v.accept(visitor);
   }
 }
 
+class SimpleBindingPattern extends BindingPattern {
+  final Identifier name;
+  SimpleBindingPattern(Identifier name)
+      : super([new DestructuredVariable(name: name)]), this.name = name;
+  accept(NodeVisitor visitor) => visitor.visitSimpleBindingPattern(this);
+
+  /// Avoid parenthesis when pretty-printing.
+  @override int get precedenceLevel => PRIMARY;
+  @override Node _clone() => new SimpleBindingPattern(name);
+}
+
 class ObjectBindingPattern extends BindingPattern {
   ObjectBindingPattern(List<DestructuredVariable> variables)
       : super(variables);
   accept(NodeVisitor visitor) => visitor.visitObjectBindingPattern(this);
 
   /// Avoid parenthesis when pretty-printing.
   @override int get precedenceLevel => PRIMARY;
   @override Node _clone() => new ObjectBindingPattern(variables);
 }
 
@@ skipping 935 matching lines @@
 
   final List<ModuleItem> body;
   Module(this.body, {this.name});
 
   accept(NodeVisitor visitor) => visitor.visitModule(this);
   void visitChildren(NodeVisitor visitor) {
     for (ModuleItem item in body) item.accept(visitor);
   }
   Module _clone() => new Module(body);
 }