diff --git a/phpstan-baseline.php b/phpstan-baseline.php
index 3ff44bea6437..11487806e48d 100644
--- a/phpstan-baseline.php
+++ b/phpstan-baseline.php
@@ -2981,11 +2981,6 @@
 	'count' => 1,
 	'path' => __DIR__ . '/system/Session/Handlers/RedisHandler.php',
 ];
-$ignoreErrors[] = [
-	'message' => '#^Only booleans are allowed in a negated boolean, int given\\.$#',
-	'count' => 1,
-	'path' => __DIR__ . '/system/Session/Handlers/RedisHandler.php',
-];
 $ignoreErrors[] = [
 	'message' => '#^Accessing offset \'HTTP_X_REQUESTED_WITH\' directly on \\$_SERVER is discouraged\\.$#',
 	'count' => 2,
diff --git a/system/Cache/Handlers/RedisHandler.php b/system/Cache/Handlers/RedisHandler.php
index 42b44cd98a96..953de2dc20be 100644
--- a/system/Cache/Handlers/RedisHandler.php
+++ b/system/Cache/Handlers/RedisHandler.php
@@ -245,6 +245,7 @@ public function getMetaData(string $key)
         if ($value !== null) {
             $time = Time::now()->getTimestamp();
             $ttl  = $this->redis->ttl(static::validateKey($key, $this->prefix));
+            assert(is_int($ttl));
 
             return [
                 'expire' => $ttl > 0 ? $time + $ttl : null,
diff --git a/system/Session/Handlers/RedisHandler.php b/system/Session/Handlers/RedisHandler.php
index 815e3644984b..1fb87597ab8a 100644
--- a/system/Session/Handlers/RedisHandler.php
+++ b/system/Session/Handlers/RedisHandler.php
@@ -293,7 +293,10 @@ protected function lockSession(string $sessionID): bool
         $attempt = 0;
 
         do {
-            if (($ttl = $this->redis->ttl($lockKey)) > 0) {
+            $ttl = $this->redis->ttl($lockKey);
+            assert(is_int($ttl));
+
+            if ($ttl > 0) {
                 sleep(1);
 
                 continue;