anchor.diff:      return visit(node.expression)(f, s);
     };
   
  -  visitPostfixExpression(ast.PostfixExpression node) => unimplemented(node);
  +  visitPostfixExpression(ast.PostfixExpression node) => (f, s) {
  +    return visit(node.operand)(f, (expr) {
  +      return s(AstFactory.postfixExpression(expr, node.operator.type));
  +    });
  +  };
   
     visitPrefixExpression(ast.PrefixExpression node) => (f, s) {
       return visit(node.operand)(f, (expr) {
  
positive.code:           _asCascadeSection(node.leftHandSide), node.operator.type,
            node.rightHandSide);
      }
    }
  
    visitCascadeExpression(ast.CascadeExpression node) => (f, s) {
  
negative.code: 
    visitVariableDeclarationStatement(
        ast.VariableDeclarationStatement node) => (f, r, s) {
      // TODO(kmillikin): A null keyword indicates a type.  Do not discard it!
      var keyword = node.variables.keyword == null
          ? scanner.Keyword.VAR
          : scanner.Keyword.keywords[node.variables.keyword.lexeme];
      return _translateDeclarationList(keyword, node.variables)(f, (decls) {
        _residualizeDeclarationList(keyword, decls);
        return s();
  