title: Adding Default Constructor parameter to record using Automapper
body: <p>Im trying to use automapper to map from one record to a new record and add a few defaults based on some logic.
  I was originally expecting &quot;ForCtorParam&quot; to work, but im still getting the same exception after adding it.</p>
  <pre><code>    public record Source(
          int number);
      public record Destination(
          int number,
          string numberAsString);
      [Fact]
      public void automapperTest()
      {
          var config = new MapperConfiguration(cfg =&gt;
          {
              cfg.CreateMap&lt;Source, Destination&gt;()
              .ForCtorParam(&quot;numberAsString&quot;, (opt) =&gt; opt.MapFrom((src) =&gt; src.number.ToString()));
          });
          config.AssertConfigurationIsValid();
      }
  </code></pre>
  <p>Im not sure if i am trying to do something that is not intended or missunderstanding the automapper documentation.</p>
  <p>Hoping someone in here can help
  TIA</p>