title: ASPNET Core 3.0 Model validation error with Inheritance
body: <p>I just moved to ASP.NET Core 3.0 and it seems that either model validation with inheritance is broken, or I am missing something. When I post the following model with <code>IlVal00 = null</code>, it says: </p>
  
  <blockquote>
    <p>title=One or more validation errors occurred. status=400, The IlVal00 field is required.</p>
  </blockquote>
  
  <pre class="lang-cs prettyprint-override"><code>public class Stock : BaseClass
  {
      [Required]
      public string Ref { get; set; } = default!;
  }
  
  public class BaseClass
  {
      public string? IlVal00 { get; set; }
  }
  </code></pre>
  
  <p>But if I change my model to the following, it works:</p>
  
  <pre class="lang-cs prettyprint-override"><code>public class Stock : BaseClass
  {
       [Required]
       public string Ref { get; set; } = default!;
  
       public new string? IlVal00 { get; set; }
  }
  
  public class BaseClass
  {
       public string? IlVal00 { get; set; }
  }
  </code></pre>
  
  <p>But I need this to support inheritance. Does anyone have an idea for how to make this work?</p>
  
  <p>Thanks.</p>