title: Moshi 1.9.1 Cannot serialize Kotlin type
body: <p>I have a working code serializing/deserializing data using Moshi 1.8.0</p>
  
  <p>Upgrading to 1.9.1 now leads to a crash when attempting to serialize:</p>
  
  <blockquote>
    <p>java.lang.IllegalArgumentException: Cannot serialize Kotlin type
    com.xxx.Spot. Reflective serialization of Kotlin classes without
    using kotlin-reflect has undefined and unexpected behavior. Please use
    KotlinJsonAdapter from the moshi-kotlin artifact or use code gen from
    the moshi-kotlin-codegen artifact.</p>
  </blockquote>
  
  <p>Here is the serializer code:</p>
  
  <pre><code>val moshi = Moshi.Builder().build()
  val dataListType = newParameterizedType(List::class.java, T::class.java)
  val adapter: JsonAdapter&lt;List&lt;T&gt;&gt; = moshi.adapter(dataListType)
  val json = adapter.toJson(dataList)
  </code></pre>
  
  <p>and the corresponding T class is </p>
  
  <pre><code>@IgnoreExtraProperties
  data class Spot(
      var id: String = "",
      var localizedName: String? = null,
      var type: String = "",
      var location: Location? = null
  )
  </code></pre>
  
  <p>I'm totally clueless about what to do here.</p>
  
  <p>Thanks for the help!</p>