diff --git a/src/workflow/ArcanistDiffWorkflow.php b/src/workflow/ArcanistDiffWorkflow.php
--- a/src/workflow/ArcanistDiffWorkflow.php
+++ b/src/workflow/ArcanistDiffWorkflow.php
@@ -494,6 +494,7 @@
     $this->updateLintDiffProperty();
     $this->updateUnitDiffProperty();
     $this->updateLocalDiffProperty();
+    $this->updateGeneratedDiffProperty();
     $this->resolveDiffPropertyUpdates();
 
     $output_json = $this->getArgument('json');
@@ -2360,6 +2361,18 @@
     $this->updateDiffProperty('local:commits', json_encode($local_info));
   }
 
+  /**
+   * Update generated paths for the diff.
+   *
+   * @task diffprop
+   */
+  private function updateGeneratedDiffProperty() {
+    $paths = $this->getWorkingCopy()->getProjectConfig('generated-paths');
+
+    if ($paths) {
+      $this->updateDiffProperty('arc:generated', json_encode($paths));
+    }
+  }
 
   /**
    * Update an arbitrary diff property.