Regression test

Closes phpstan/phpstan#6158

Author: ondrejmirtes

tests/PHPStan/Rules/TooWideTypehints/TooWideMethodReturnTypehintRuleTest.php

@@ -88,4 +88,9 @@ public function testBug5095(): void
 		]);
 	}
 
+	public function testBug6158(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-6158.php'], []);
+	}
+
 }

tests/PHPStan/Rules/TooWideTypehints/data/bug-6158.php

@@ -0,0 +1,87 @@
+<?php
+
+namespace Bug6158;
+
+/**
+ * @template TKey of array-key
+ * @template T
+ * @implements ArrayAccess<TKey|null, T>
+ */
+class Collection implements \ArrayAccess {
+
+	/** @var array<TKey|null, T> */
+	private array $values;
+
+	/**
+	 * @param TKey $offset
+	 */
+	final public function offsetExists(mixed $offset): bool
+	{
+		return array_key_exists($offset, $this->values);
+	}
+
+	/**
+	 * @param TKey $offset
+	 *
+	 * @return T
+	 */
+	final public function offsetGet(mixed $offset): mixed
+	{
+		return $this->values[$offset];
+	}
+
+	/**
+	 * @param TKey|null $offset
+	 * @param T    $value
+	 */
+	final public function offsetSet($offset, $value): void
+	{
+		$this->values[$offset] = $value;
+	}
+
+	/**
+	 * @param TKey $offset
+	 */
+	final public function offsetUnset($offset): void
+	{
+		unset($this->values[$offset]);
+	}
+
+	/** @return T|null */
+	final public function randValue(): mixed
+	{
+		if ($this->values === []) {
+			return null;
+		}
+
+		return $this[array_rand($this->values)];
+	}
+}
+
+final class User {
+
+	public UserCollection $users;
+
+	public function __construct()
+	{
+		$this->users = new UserCollection();
+	}
+
+	public function randValue(): ?User
+	{
+		return $this->rand();
+	}
+
+	private function rand(): ?User
+	{
+		return $this->users->randValue();
+	}
+
+}
+
+/**
+ * @extends Collection<array-key, User>
+ */
+class UserCollection extends Collection
+{
+}