fix #29733, handle variables that completely shadow parameters

pkg/dev_compiler/lib/src/js_ast/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> implements TypeRefVisitor<T> {
   T visitProgram(Program node);
 
   T visitBlock(Block node);
@@ skipping 234 matching lines @@
   T visitAnyTypeRef(AnyTypeRef node) => visitTypeRef(node);
   T visitUnknownTypeRef(UnknownTypeRef node) => visitTypeRef(node);
   T visitArrayTypeRef(ArrayTypeRef node) => visitTypeRef(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;
+  ClosureAnnotation closureAnnotation;
 
   accept(NodeVisitor visitor);
   void visitChildren(NodeVisitor visitor);
 
   // Shallow clone of node.  Does not clone positions since the only use of this
   // private method is create a copy with a new position.
   Node _clone();
 
-  withClosureAnnotation(ClosureAnnotation closureAnnotation) {
-    if (this.closureAnnotation == closureAnnotation) return this;
-
-    return _clone()
-      ..sourceInformation = sourceInformation
-      .._closureAnnotation = closureAnnotation;
-  }
-
   // Returns a node equivalent to [this], but with new source position and end
   // source position.
   Node withSourceInformation(sourceInformation) {
     if (sourceInformation == this.sourceInformation) {
       return this;
     }
     Node clone = _clone();
     // TODO(sra): Should existing data be 'sticky' if we try to overwrite with
     // `null`?
     clone.sourceInformation = sourceInformation;
@@ skipping 1628 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);
 }