diff --git a/lib/Net/LDAP3.php b/lib/Net/LDAP3.php
index 89851c24a71f5eeb44cbb414dcf29b1c3c4b9a02..36ec6c41871417881724de8dc641ece7e88b6da0 100644
--- a/lib/Net/LDAP3.php
+++ b/lib/Net/LDAP3.php
@@ -3066,8 +3066,8 @@ class Net_LDAP3
         }
 
         $ckey = 'domain.root::' . $domain;
-        if ($result = $this->icache[$ckey]) {
-            return $result;
+        if (array_key_exists($ckey, $this->icache)) {
+            return $this->icache[$ckey];
         }
 
         $this->_debug("Net_LDAP3::domain_root_dn($domain)");
@@ -3120,7 +3120,7 @@ class Net_LDAP3
         $ckey  = 'domain::' . $domain;
         $ickey = $ckey . '::' . md5(implode(',', $attributes));
 
-        if (isset($this->icache[$ickey])) {
+        if (array_key_exists($ckey, $this->icache)) {
             return $this->icache[$ickey];
         }