title: Why there's no Nullable-Generic Methods? which accept both references and value types
body: <p>This Works</p>
  
  <pre><code>    public static T? Read&lt;T&gt;(object value) where T : struct
      {
          return (T)Convert.ChangeType(value, typeof(T));
      }
  </code></pre>
  
  <p>But this doesn't work:</p>
  
  <blockquote>
    <p>Error CS8370  Feature 'nullable reference types' are not available in C# 7.3. Please use language version 8.0 or greater.</p>
  </blockquote>
  
  <pre><code>   public static T? Read&lt;T&gt;(object value)
      {
          return (T)Convert.ChangeType(value, typeof(T));
      }
  </code></pre>
  
  <p>I am curious about the error or feature I have searched but nothing found.</p>
  
  <p>I may be <strong>deleted</strong> the question if not related. so please inform me of doing that.</p>