diff --git a/bin/naive-benchmark.php b/bin/naive-benchmark.php
index 8b0bfeb..e7044dd 100644
--- a/bin/naive-benchmark.php
+++ b/bin/naive-benchmark.php
@@ -127,7 +127,8 @@ private static function getImplementations(
       'uncached prefix match' => () ==>
         PrefixMatchingResolver::fromFlatMap($map),
       'cached prefix map' => () ==> {
-        $prefix_map = \apc_fetch(__FUNCTION__);
+        $_success = null;
+        $prefix_map = \apc_fetch(__FUNCTION__, inout $_success);
         if ($prefix_map === false) {
           $prefix_map =
             Dict\map($map, $v ==> PrefixMatching\PrefixMap::fromFlatMap($v));
diff --git a/src/router/BaseRouter.php b/src/router/BaseRouter.php
index 3ffe2bd..8616e5c 100644
--- a/src/router/BaseRouter.php
+++ b/src/router/BaseRouter.php
@@ -66,7 +66,8 @@ protected function getResolver(): IResolver<TResponder> {
     if (is_dev()) {
       $routes = null;
     } else {
-      $routes = \apc_fetch(__FILE__.'/cache');
+      $_success = null;
+      $routes = \apc_fetch(__FILE__.'/cache', inout $_success);
       if ($routes === false) {
         $routes = null;
       }