diff --git a/src/ParamResolver.php b/src/ParamResolver.php
index cb181e4..54b3fdd 100644
--- a/src/ParamResolver.php
+++ b/src/ParamResolver.php
@@ -142,13 +142,11 @@ private function resolveString(string $value, array $resolving = []): mixed
             return $this->resolveString($resolved, $resolving);
         }, $value);
 
-        if (!isset($onlyKey)) {
-            return $replaced;
+        if ($setKey = isset($onlyKey)) {
+            $resolving[$onlyKey] = true;
         }
 
-        $resolving[$onlyKey] = true;
-
-        return $this->resolveValue($this->get($onlyKey), $resolving);
+        return $setKey ? $this->resolveValue($this->get($onlyKey), $resolving) : $replaced;
     }
 
     /**