diff --git a/src/Mutator/Removal/ArrayItemRemoval.php b/src/Mutator/Removal/ArrayItemRemoval.php
index 1b54a4857..c491eab0f 100644
--- a/src/Mutator/Removal/ArrayItemRemoval.php
+++ b/src/Mutator/Removal/ArrayItemRemoval.php
@@ -66,15 +66,17 @@ public function __construct(MutatorConfig $config)
         $this->limit = $settings['limit'];
     }
 
+    /**
+     * @param Node|Node\Expr\Array_  $arrayNode
+     * @return Node|Node[]|\Generator
+     */
     public function mutate(Node $arrayNode): Generator
     {
-        if ($arrayNode instanceof Node\Expr\Array_) {
-            foreach ($this->getItemsIndexes($arrayNode->items) as $indexToRemove) {
-                $newArrayNode = clone $arrayNode;
-                unset($newArrayNode->items[$indexToRemove]);
+        foreach ($this->getItemsIndexes($arrayNode->items) as $indexToRemove) {
+            $newArrayNode = clone $arrayNode;
+            unset($newArrayNode->items[$indexToRemove]);
 
-                yield $newArrayNode;
-            }
+            yield $newArrayNode;
         }
     }
 
diff --git a/tests/Mutator/Removal/ArrayItemRemovalTest.php b/tests/Mutator/Removal/ArrayItemRemovalTest.php
index f5ecdb5cc..9b3e3a950 100644
--- a/tests/Mutator/Removal/ArrayItemRemovalTest.php
+++ b/tests/Mutator/Removal/ArrayItemRemovalTest.php
@@ -56,7 +56,6 @@ public function provideMutationCases(): Generator
     {
         yield 'It does not mutate empty arrays' => [
             '<?php $a = [];',
-            null,
         ];
 
         yield 'It removes only first item by default' => [
@@ -113,7 +112,11 @@ public function provideMutationCases(): Generator
     public function test_settings_validation(string $setting, $value, string $valueInError): void
     {
         $this->expectException(InvalidConfigException::class);
-        $this->expectExceptionMessage("Invalid configuration of ArrayItemRemoval mutator. Setting `$setting` is invalid ($valueInError)");
+        $this->expectExceptionMessage(sprintf(
+            'Invalid configuration of ArrayItemRemoval mutator. Setting `%s` is invalid (%s)',
+            $setting,
+            $valueInError
+        ));
         $this->doTest(
             '<?php $a = [1, 2, 3];',
             "<?php\n\n\$a = [2, 3];",