title: Using System.Dynamic in Roslyn
body: <p>I modified the example that comes with the new version of Roslyn that was released yesterday to use dynamic and ExpandoObject but I am getting a compiler error which I am not sure how to fix. The error is:</p>
  
  <blockquote>
    <p>(7,21): error CS0656: Missing compiler required member 'Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo.Create'</p>
  </blockquote>
  
  <p>Can you not use dynamics in the new compiler yet? How can I fix this? Here is the example that I updated:</p>
  
  <pre><code>[TestMethod]
  public void EndToEndCompileAndRun()
  {
      var text = @"using System.Dynamic;
      public class Calculator
      {
          public static object Evaluate()
          {
              dynamic x = new ExpandoObject();
              x.Result = 42;
              return x.Result;
          } 
      }";
  
      var tree = SyntaxFactory.ParseSyntaxTree(text);
      var compilation = CSharpCompilation.Create(
          "calc.dll",
          options: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary),
          syntaxTrees: new[] {tree},
          references: new[] {new MetadataFileReference(typeof (object).Assembly.Location), new MetadataFileReference(typeof (ExpandoObject).Assembly.Location)});
  
      Assembly compiledAssembly;
      using (var stream = new MemoryStream())
      {
          var compileResult = compilation.Emit(stream);
          compiledAssembly = Assembly.Load(stream.GetBuffer());
      }
  
      Type calculator = compiledAssembly.GetType("Calculator");
      MethodInfo evaluate = calculator.GetMethod("Evaluate");
      string answer = evaluate.Invoke(null, null).ToString();
  
      Assert.AreEqual("42", answer);
  }
  </code></pre>