title: Fragment databinding, DataBinderMapperImpl.java cannot find symbol FragmentCollectionBindingImpl
body: <p>I'm binding data between android fragment and ViewModel in kotlin. Compiler throws </p>
  
  <blockquote>
    <p>error: cannot find symbolimport >frydzej.yerbet.databinding.FragmentCollectionBindingImpl</p>
  </blockquote>
  
  <p>I have tried to change gradle version to 3.2.1 and databinding compiler version to 3.2.1. But with same result.
  My Android Studio version is 3.3 RC 3</p>
  
  <p>This is my project gradle buildscript</p>
  
  <pre><code>buildscript {
  ext.kotlin_version = '1.3.11'
  repositories {
      google()
      jcenter()
  }
  dependencies {
      classpath 'com.android.tools.build:gradle:3.3.0-rc03'
      classpath "org.jetbrains.kotlin:kotlin-gradle- 
  plugin:$kotlin_version"
      classpath 'android.arch.navigation:navigation-safe-args-gradle- 
  plugin:1.0.0-alpha09'
   }
  }
  </code></pre>
  
  <p>and app gradle</p>
  
  <pre><code>dataBinding{
          enabled = true
      }
  
  dependencies {
      def lifecycle_version = "2.0.0"
      def room_version = "2.0.0"
      implementation fileTree(dir: 'libs', include: ['*.jar'])
      implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
      implementation 'androidx.appcompat:appcompat:1.1.0-alpha01'
      implementation 'com.google.android.material:material:1.1.0-alpha02'
      implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
      implementation "android.arch.navigation:navigation-fragment-ktx:1.0.0-alpha09"
      implementation "android.arch.navigation:navigation-ui-ktx:1.0.0-alpha09"
      implementation 'androidx.legacy:legacy-support-v4:1.0.0'
      implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
      implementation 'com.cuneytayyildiz:onboarder:1.0.3'
      implementation 'com.android.support:design:28.0.0'
      implementation 'androidx.recyclerview:recyclerview:1.0.0'
      implementation 'com.google.android.material:material:1.0.0'
      implementation 'androidx.appcompat:appcompat:1.0.2'
      implementation "androidx.room:room-runtime:$room_version"
      kapt "androidx.room:room-compiler:$room_version"
      kapt "androidx.lifecycle:lifecycle-compiler:$lifecycle_version"
      testImplementation 'junit:junit:4.12'
      debugImplementation 'com.amitshekhar.android:debug-db:1.0.4'
      androidTestImplementation 'androidx.test:runner:1.1.1'
      androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
  }
  </code></pre>
  
  <p>fragment_collection.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  
  &lt;layout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      xmlns:app="http://schemas.android.com/apk/res-auto"&gt;
  &lt;data&gt;
      &lt;variable name="viewModel" type="frydzej.yerbet.viewModels.CollectionViewModel"/&gt;
  &lt;/data&gt;
  
  &lt;FrameLayout
          android:layout_width="match_parent" android:layout_height="match_parent"
          tools:context=".Views.CollectionFragment"&gt;
  
      &lt;com.google.android.material.floatingactionbutton.FloatingActionButton
              android:id="@+id/add_item_fab"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_gravity="end|bottom"
              android:src="@drawable/ic_add"
              android:onClick="@{() -&gt; viewModel.addFabClicked()}"
              android:layout_margin="16dp"
              app:fabSize="normal"/&gt;
  &lt;/FrameLayout&gt;
  &lt;/layout&gt;
  </code></pre>
  
  <p>and the Fragment view code:</p>
  
  <pre><code>override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
      val binding: FragmentCollectionBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_collection, container, false)
      val view: View = binding.root
      val viewModel: CollectionViewModel = ViewModelProviders.of(this).get(CollectionViewModel::class.java)
      binding.viewModel = viewModel
      return view
  }
  </code></pre>
  
  <p>In MainActivity databinding there is either </p>
  
  <blockquote>
    <p>ActivityMainBinding 
    and 
    ActivityMainBindingImpl, </p>
  </blockquote>
  
  <p>but in CollectionFragment only </p>
  
  <blockquote>
    <p>FragmentCollectionBinding </p>
  </blockquote>
  
  <p>is created</p>