title: Build fails with 'Program type already present: android.arch.core.util.Function'
body: <p>After updating my Firebase and Play Services dependencies as well as the Play Services Plugin my project fails to build. I've tried multiple Clean-Rebuilds and my app has MultiDex enabled. Reverting to my original dependency versions is also not an option as I added a dependency for cloud functions for which the latest version is incompatible with my other firebase dependencies. I can see the following under Android Issues</p>
  
  <pre><code>Program type already present: android.arch.core.util.Function
  Message{kind=ERROR, text=Program type already present:  android.arch.core.util.Function, sources=[Unknown source file], tool name=Optional.of(D8)}
  </code></pre>
  
  <p>I also see an error message under Run Tasks</p>
  
  <pre><code>org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:transformDexArchiveWithExternalLibsDexMergerForDebug'.
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:100)
  at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:70)
  at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
  at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:62)
  at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
  at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:60)
  at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:97)
  at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:87)
  at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:52)
  at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
  at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
  at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
  at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
  at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:248)
  at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
  at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
  at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
  at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
  at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:241)
  at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:230)
  at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:123)
  at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:79)
  at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:104)
  at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:98)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:626)
  at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:581)
  at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
  at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
  at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
  at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
  at java.lang.Thread.run(Thread.java:745)
  Caused by: java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives: 
  </code></pre>
  
  <p>My gradle dependencies</p>
  
  <pre><code>dependencies {
      implementation fileTree(include: ['*.jar'], dir: 'libs')
      debugImplementation 'com.squareup.leakcanary:leakcanary-android:1.5.4'
      releaseImplementation 'com.squareup.leakcanary:leakcanary-android-no-op:1.5.4'
      implementation 'com.android.support:multidex:1.0.3'
  
      //Android Support
      implementation 'com.android.support:support-v13:27.1.1'
      implementation 'com.android.support:appcompat-v7:27.1.1'
      implementation 'com.android.support:design:27.1.1'
      implementation 'com.android.support:recyclerview-v7:27.1.1'
      implementation "com.android.support:cardview-v7:27.1.1"
      implementation "com.android.support:customtabs:27.1.1"
      implementation 'com.android.support.constraint:constraint-layout:1.1.0'
      implementation "com.android.support:support-v4:27.1.1"
  
      //Firebase
      implementation 'com.google.firebase:firebase-core:16.0.0'
      implementation 'com.google.firebase:firebase-analytics:16.0.0'
      implementation 'com.google.firebase:firebase-appindexing:15.0.1'
      implementation 'com.google.firebase:firebase-auth:16.0.1' //Maintain compatibility with com.firebaseui:firebase-ui-firestore
      implementation 'com.google.firebase:firebase-firestore:17.0.1' //Maintain compatibility with com.firebaseui:firebase-ui-firestore
      implementation 'com.google.firebase:firebase-functions:16.0.1'
      implementation 'com.google.firebase:firebase-messaging:17.0.0'
      //implementation 'com.google.firebase:firebase-storage:16.0.1' //Maintain compatibility with com.firebaseui:firebase-ui-firestore
      implementation('com.crashlytics.sdk.android:crashlytics:2.9.1@aar') {
          transitive = true
      }
      //implementation 'com.google.firebase:firebase-invites:16.0.0'
      implementation 'com.google.firebase:firebase-config:16.0.0'
  
      //Google Play
      implementation 'com.google.android.gms:play-services-ads:15.0.1'
      implementation 'com.google.android.gms:play-services-places:15.0.1'
      implementation 'com.google.android.gms:play-services-location:15.0.1'
  
      //Stream Support
      implementation 'net.sourceforge.streamsupport:android-retrostreams:1.6.1'
      implementation 'net.sourceforge.streamsupport:android-retroflow:1.6.1'
      implementation 'net.sourceforge.streamsupport:android-retrofuture:1.6.1'
  
      //Location
      implementation 'io.nlopez.smartlocation:library:3.3.3'
  
      //Firebase UI
      implementation 'com.firebaseui:firebase-ui-firestore:4.0.0'
  
      //Facebook
      implementation 'com.facebook.android:facebook-login:4.31.0'
  
      //Search
      implementation 'com.algolia:algoliasearch-android:3.14.1'
  
      //Butterknife
      implementation 'com.jakewharton:butterknife:8.8.1'
      annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'
  
      //UI Elements for layout staggering
      implementation 'com.google.android:flexbox:0.3.2'
  
      //Image Handling Library
      implementation 'com.facebook.fresco:fresco:1.8.0'
  
      // UI Element for Country-code
      implementation 'com.hbb20:ccp:2.1.2'
  
      // UI Element for OTP
      implementation 'com.github.GoodieBag:Pinview:v1.3'
  
      //Loading indicator using shimmer
      implementation 'io.supercharge:shimmerlayout:2.0.0'
  
      //UI Element for Tooltip
      implementation 'it.sephiroth.android.library.targettooltip:target-tooltip-library:1.3.15'
  
      //Date/Time Pickers for Hangout Creation
      implementation 'com.wdullaer:materialdatetimepicker:3.5.1'
  
      //UI Element from Drop-down boxes
      implementation('com.weiwangcn.betterspinner:library-material:1.1.0') {
          exclude group: 'com.android.support', module: 'appcompat-v7'
          exclude group: 'com.android.support', module: 'appcompat-v4'
      }
  
      //JSON Handling
      implementation 'com.google.code.gson:gson:2.8.2'
  
      //Permissions using RxPermissions
      implementation 'com.tbruyelle.rxpermissions2:rxpermissions:0.9.5@aar'
  
      //RxBindings for Platform
      implementation 'com.jakewharton.rxbinding2:rxbinding:2.1.1'
      implementation 'com.jakewharton.rxbinding2:rxbinding-recyclerview-v7:2.1.1'
      implementation 'com.jakewharton.rxbinding2:rxbinding-appcompat-v7:2.1.1'
      implementation 'com.jakewharton.rxbinding2:rxbinding-design:2.1.1'
  
      //Logging
      implementation 'com.jakewharton.timber:timber:4.6.0'
  
      //Testing
      testImplementation 'junit:junit:4.12'
      androidTestImplementation 'com.android.support.test:runner:1.0.2'
      androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
  }
  </code></pre>