diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -459,6 +459,7 @@
     'DifferentialUnitStatus' => 'applications/differential/constants/DifferentialUnitStatus.php',
     'DifferentialUnitTestResult' => 'applications/differential/constants/DifferentialUnitTestResult.php',
     'DifferentialViewPolicyField' => 'applications/differential/customfield/DifferentialViewPolicyField.php',
+    'DiffusionArcanistProjectDatasource' => 'applications/diffusion/typeahead/DiffusionArcanistProjectDatasource.php',
     'DiffusionBranchTableController' => 'applications/diffusion/controller/DiffusionBranchTableController.php',
     'DiffusionBranchTableView' => 'applications/diffusion/view/DiffusionBranchTableView.php',
     'DiffusionBrowseController' => 'applications/diffusion/controller/DiffusionBrowseController.php',
@@ -3175,6 +3176,7 @@
     'DifferentialTransactionView' => 'PhabricatorApplicationTransactionView',
     'DifferentialUnitField' => 'DifferentialCustomField',
     'DifferentialViewPolicyField' => 'DifferentialCoreCustomField',
+    'DiffusionArcanistProjectDatasource' => 'PhabricatorTypeaheadDatasource',
     'DiffusionBranchTableController' => 'DiffusionController',
     'DiffusionBranchTableView' => 'DiffusionView',
     'DiffusionBrowseController' => 'DiffusionController',
diff --git a/src/applications/diffusion/typeahead/DiffusionArcanistProjectDatasource.php b/src/applications/diffusion/typeahead/DiffusionArcanistProjectDatasource.php
new file mode 100644
--- /dev/null
+++ b/src/applications/diffusion/typeahead/DiffusionArcanistProjectDatasource.php
@@ -0,0 +1,30 @@
+<?php
+
+final class DiffusionArcanistProjectDatasource
+  extends PhabricatorTypeaheadDatasource {
+
+  public function getPlaceholderText() {
+    return pht('Type an arcanist project name...');
+  }
+
+  public function getDatasourceApplicationClass() {
+    return 'PhabricatorApplicationDiffusion';
+  }
+
+  public function loadResults() {
+    $viewer = $this->getViewer();
+    $raw_query = $this->getRawQuery();
+
+    $results = array();
+
+    $arcprojs = id(new PhabricatorRepositoryArcanistProject())->loadAll();
+    foreach ($arcprojs as $proj) {
+      $results[] = id(new PhabricatorTypeaheadResult())
+        ->setName($proj->getName())
+        ->setPHID($proj->getPHID());
+    }
+
+    return $results;
+  }
+
+}
diff --git a/src/applications/herald/controller/HeraldRuleController.php b/src/applications/herald/controller/HeraldRuleController.php
--- a/src/applications/herald/controller/HeraldRuleController.php
+++ b/src/applications/herald/controller/HeraldRuleController.php
@@ -593,6 +593,7 @@
       'legaldocuments' => new LegalpadDocumentDatasource(),
       'taskpriority' => new ManiphestTaskPriorityDatasource(),
       'buildplan' => new HarbormasterBuildPlanDatasource(),
+      'arcanistprojects' => new DiffusionArcanistProjectDatasource(),
     );
 
     $sources = mpull($sources, 'getDatasourceURI');
@@ -602,7 +603,6 @@
       'package'       => '/typeahead/common/packages/',
       'project'       => '/typeahead/common/projects/',
       'userorproject' => '/typeahead/common/accountsorprojects/',
-      'arcanistprojects' => '/typeahead/common/arcanistprojects/',
     );
 
     return array(
diff --git a/src/applications/repository/controller/PhabricatorRepositoryArcanistProjectEditController.php b/src/applications/repository/controller/PhabricatorRepositoryArcanistProjectEditController.php
--- a/src/applications/repository/controller/PhabricatorRepositoryArcanistProjectEditController.php
+++ b/src/applications/repository/controller/PhabricatorRepositoryArcanistProjectEditController.php
@@ -95,7 +95,7 @@
         id(new AphrontFormTokenizerControl())
           ->setLabel('Uses Symbols From')
           ->setName('symbolIndexProjects')
-          ->setDatasource('/typeahead/common/arcanistprojects/')
+          ->setDatasource(new DiffusionArcanistProjectDatasource())
           ->setValue($uses))
       ->appendChild(
         id(new AphrontFormSubmitControl())
diff --git a/src/applications/typeahead/controller/PhabricatorTypeaheadCommonDatasourceController.php b/src/applications/typeahead/controller/PhabricatorTypeaheadCommonDatasourceController.php
--- a/src/applications/typeahead/controller/PhabricatorTypeaheadCommonDatasourceController.php
+++ b/src/applications/typeahead/controller/PhabricatorTypeaheadCommonDatasourceController.php
@@ -28,7 +28,6 @@
     $need_projs = false;
     $need_packages = false;
     $need_upforgrabs = false;
-    $need_arcanist_projects = false;
     $need_noproject = false;
     $need_symbols = false;
     $need_jump_objects = false;
@@ -76,9 +75,6 @@
       case 'packages':
         $need_packages = true;
         break;
-      case 'arcanistprojects':
-        $need_arcanist_projects = true;
-        break;
     }
 
     $results = array();
@@ -243,15 +239,6 @@
       }
     }
 
-    if ($need_arcanist_projects) {
-      $arcprojs = id(new PhabricatorRepositoryArcanistProject())->loadAll();
-      foreach ($arcprojs as $proj) {
-        $results[] = id(new PhabricatorTypeaheadResult())
-          ->setName($proj->getName())
-          ->setPHID($proj->getPHID());
-      }
-    }
-
     if ($need_applications) {
       $applications = PhabricatorApplication::getAllInstalledApplications();
       foreach ($applications as $application) {