$cell_data = [];

if($test_data !== NULL) { // optional cell datas
	$cell_data[‘test’] = $test_data;
}
view_cell(‘test’, $cell_data); // array_key_exists null fix.

system/View/Cell.php

@@ -95,6 +95,7 @@ public function render(string $library, $params = null, int $ttl = 0, string $ca
 		}
 		elseif (
 			($paramCount === 1)
+			&& ($paramArray !== null)
 			&& (
 				(! array_key_exists($refParams[0]->name, $paramArray))
 				|| (
@@ -111,20 +112,23 @@ public function render(string $library, $params = null, int $ttl = 0, string $ca
 			$fireArgs = [];
 			$method_params = [];
 
-			foreach($refParams as $arg)
+			if($paramArray !== null)
 			{
-				$method_params[$arg->name] = true;
-				if (array_key_exists($arg->name, $paramArray))
+				foreach($refParams as $arg)
 				{
-					$fireArgs[$arg->name] = $paramArray[$arg->name];
+					$method_params[$arg->name] = true;
+					if (array_key_exists($arg->name, $paramArray))
+					{
+						$fireArgs[$arg->name] = $paramArray[$arg->name];
+					}
 				}
-			}
 
-			foreach ($paramArray as $key => $val)
-			{
-				if (! isset($method_params[$key]))
+				foreach ($paramArray as $key => $val)
 				{
-					throw new \InvalidArgumentException("{$key} is not a valid param name.");
+					if (! isset($method_params[$key]))
+					{
+						throw new \InvalidArgumentException("{$key} is not a valid param name.");
+					}
 				}
 			}
 
@@ -225,4 +229,4 @@ protected function determineClass(string $library)
 	}
 
 	//--------------------------------------------------------------------
-}
+}