diff --git a/src/applications/differential/editor/DifferentialCommentEditor.php b/src/applications/differential/editor/DifferentialCommentEditor.php
index 386a0d9e22..8054b791c5 100644
--- a/src/applications/differential/editor/DifferentialCommentEditor.php
+++ b/src/applications/differential/editor/DifferentialCommentEditor.php
@@ -109,7 +109,7 @@ final class DifferentialCommentEditor extends PhabricatorEditor {
     $revision->loadRelationships();
     $reviewer_phids = $revision->getReviewers();
     if ($reviewer_phids) {
-      $reviewer_phids = array_combine($reviewer_phids, $reviewer_phids);
+      $reviewer_phids = array_fuse($reviewer_phids);
     }
 
     $metadata = array();
diff --git a/src/applications/macro/controller/PhabricatorMacroListController.php b/src/applications/macro/controller/PhabricatorMacroListController.php
index db7a1fc591..6cfa39b338 100644
--- a/src/applications/macro/controller/PhabricatorMacroListController.php
+++ b/src/applications/macro/controller/PhabricatorMacroListController.php
@@ -65,7 +65,7 @@ final class PhabricatorMacroListController
     }
 
     if ($authors) {
-      $author_phids = array_combine($authors, $authors);
+      $author_phids = array_fuse($authors);
     } else {
       $author_phids = array();
     }
diff --git a/src/applications/metamta/storage/PhabricatorMetaMTAMail.php b/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
index 86f02f427e..7b98dd4299 100644
--- a/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
+++ b/src/applications/metamta/storage/PhabricatorMetaMTAMail.php
@@ -804,7 +804,7 @@ final class PhabricatorMetaMTAMail extends PhabricatorMetaMTADAO {
       return array();
     }
 
-    $phids = array_combine($phids, $phids);
+    $phids = array_fuse($phids);
 
 
     // Exclude PHIDs explicitly marked for exclusion. We use this to prevent
diff --git a/src/applications/phortune/control/PhortuneMonthYearExpiryControl.php b/src/applications/phortune/control/PhortuneMonthYearExpiryControl.php
index 34aea2791f..a4701aa11c 100644
--- a/src/applications/phortune/control/PhortuneMonthYearExpiryControl.php
+++ b/src/applications/phortune/control/PhortuneMonthYearExpiryControl.php
@@ -59,7 +59,7 @@ final class PhortuneMonthYearExpiryControl extends AphrontFormControl {
 
     $current_year = $this->getCurrentYear();
     $years = range($current_year, $current_year + 20);
-    $years = array_combine($years, $years);
+    $years = array_fuse($years);
 
     if ($this->getMonthInputValue()) {
       $selected_month = $this->getMonthInputValue();
diff --git a/src/applications/settings/panel/PhabricatorSettingsPanelAccount.php b/src/applications/settings/panel/PhabricatorSettingsPanelAccount.php
index 1e2d588016..72b58dae2a 100644
--- a/src/applications/settings/panel/PhabricatorSettingsPanelAccount.php
+++ b/src/applications/settings/panel/PhabricatorSettingsPanelAccount.php
@@ -62,7 +62,7 @@ final class PhabricatorSettingsPanelAccount
     }
 
     $timezone_ids = DateTimeZone::listIdentifiers();
-    $timezone_id_map = array_combine($timezone_ids, $timezone_ids);
+    $timezone_id_map = array_fuse($timezone_ids);
 
     $form = new AphrontFormView();
     $form
diff --git a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
index b34d64af93..7a3d07fd77 100644
--- a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
+++ b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
@@ -522,7 +522,7 @@ abstract class PhabricatorApplicationTransactionEditor
   protected function getPHIDTransactionNewValue(
     PhabricatorApplicationTransaction $xaction) {
 
-    $old = array_combine($xaction->getOldValue(), $xaction->getOldValue());
+    $old = array_fuse($xaction->getOldValue());
 
     $new = $xaction->getNewValue();
     $new_add = idx($new, '+', array());
@@ -531,7 +531,7 @@ abstract class PhabricatorApplicationTransactionEditor
     unset($new['-']);
     $new_set = idx($new, '=', null);
     if ($new_set !== null) {
-      $new_set = array_combine($new_set, $new_set);
+      $new_set = array_fuse($new_set);
     }
     unset($new['=']);
 
diff --git a/src/infrastructure/celerity/CeleritySpriteGenerator.php b/src/infrastructure/celerity/CeleritySpriteGenerator.php
index deaffac9c7..be81839173 100644
--- a/src/infrastructure/celerity/CeleritySpriteGenerator.php
+++ b/src/infrastructure/celerity/CeleritySpriteGenerator.php
@@ -183,7 +183,7 @@ final class CeleritySpriteGenerator {
     // Reorder the sprites so less-specific rules generate earlier in the sheet.
     // Otherwise we end up with blue "a.black" buttons because the blue rules
     // have the same specificity but appear later.
-    $gradients = array_combine($gradients, $gradients);
+    $gradients = array_fuse($gradients);
     $gradients = array_select_keys(
       $gradients,
       array(
diff --git a/src/infrastructure/daemon/workers/PhabricatorWorker.php b/src/infrastructure/daemon/workers/PhabricatorWorker.php
index 685771622c..3cf3159ca7 100644
--- a/src/infrastructure/daemon/workers/PhabricatorWorker.php
+++ b/src/infrastructure/daemon/workers/PhabricatorWorker.php
@@ -102,7 +102,7 @@ abstract class PhabricatorWorker {
   final public static function waitForTasks(array $task_ids) {
     $task_table = new PhabricatorWorkerActiveTask();
 
-    $waiting = array_combine($task_ids, $task_ids);
+    $waiting = array_fuse($task_ids);
     while ($waiting) {
       $conn_w = $task_table->establishConnection('w');
 
diff --git a/src/view/form/control/AphrontFormDateControl.php b/src/view/form/control/AphrontFormDateControl.php
index 4d398f2fa5..b010eed875 100644
--- a/src/view/form/control/AphrontFormDateControl.php
+++ b/src/view/form/control/AphrontFormDateControl.php
@@ -181,7 +181,7 @@ final class AphrontFormDateControl extends AphrontFormControl {
     $max_year = $this->getMaxYear();
 
     $days = range(1, 31);
-    $days = array_combine($days, $days);
+    $days = array_fuse($days);
 
     $months = array(
       1 => 'Jan',
@@ -199,7 +199,7 @@ final class AphrontFormDateControl extends AphrontFormControl {
     );
 
     $years = range($this->getMinYear(), $this->getMaxYear());
-    $years = array_combine($years, $years);
+    $years = array_fuse($years);
 
     $days_sel = AphrontFormSelectControl::renderSelectTag(
       $this->getDayInputValue(),