Add regression test for #10172

Closes phpstan/phpstan#10172

Author: phpstan-bot

tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -1310,4 +1310,9 @@ public function testBug9669(): void
 		$this->analyse([__DIR__ . '/data/bug-9669.php'], []);
 	}
 
+	public function testBug10172(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-10172.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/bug-10172.php

@@ -0,0 +1,21 @@
+<?php declare(strict_types = 1);
+
+namespace Bug10172;
+
+class HelloWorld
+{
+    /**
+     * @template T of array{data: array<mixed>}
+     *
+     * @param T $a
+     *
+     * @return T
+     */
+    public function foo(array $a): array
+    {
+        foreach ($a['data'] as $i) {
+        }
+
+        return $a;
+    }
+}