Added regression test

tests/PHPStan/Analyser/nsrt/bug-5207b.php

@@ -0,0 +1,38 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug5207b;
+
+use function PHPStan\Testing\assertType;
+
+abstract class HelloWorld {
+	abstract public function getChild(): ?HelloWorld;
+
+	public function sayHello(): void {
+		$foo = null !== $this->getChild()->getChild();
+		if ($foo) {
+			assertType('Bug5207b\HelloWorld|null', $this->getChild()); // could be Bug5207b\HelloWorld
+			assertType('Bug5207b\HelloWorld', $this->getChild()->getChild());
+			assertType('Bug5207b\HelloWorld|null', $this->getChild()->getChild()->getChild());
+		}
+	}
+
+	public function sayFoo(): void {
+		$foo = null !== $this?->getChild()?->getChild();
+		if ($foo) {
+			assertType('Bug5207b\HelloWorld', $this->getChild());
+			assertType('Bug5207b\HelloWorld', $this->getChild()->getChild());
+			assertType('Bug5207b\HelloWorld|null', $this->getChild()->getChild()->getChild());
+		}
+	}
+
+	public function sayBar(): void {
+		$foo = null !== $this?->getChild()->getChild();
+		if ($foo) {
+			assertType('Bug5207b\HelloWorld', $this->getChild());
+			assertType('Bug5207b\HelloWorld', $this->getChild()->getChild());
+			assertType('Bug5207b\HelloWorld|null', $this->getChild()->getChild()->getChild());
+		}
+	}
+}

tests/PHPStan/Rules/Methods/NullsafeMethodCallRuleTest.php

@@ -74,6 +74,17 @@ public function testBug8523c(): void
 		$this->analyse([__DIR__ . '/data/bug-8523c.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.0.0')]
+	public function testBug5207b(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-5207b.php'], [
+			[
+				'Using nullsafe method call on non-nullable type Bug5207b\OrderCustomerEntity. Use -> instead.',
+				47,
+			],
+		]);
+	}
+
 	#[RequiresPhp('>= 8.1.0')]
 	public function testBug12222(): void
 	{

tests/PHPStan/Rules/Methods/data/bug-5207b.php

@@ -0,0 +1,52 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug5207b;
+
+class OrderEntity
+{
+	public function getOrderCustomer(): ?OrderCustomerEntity
+	{
+		return new OrderCustomerEntity();
+	}
+}
+
+class OrderCustomerEntity
+{
+	public function getCustomer(): ?CustomerEntity
+	{
+		return null;
+	}
+
+	public function getEmail(): string
+	{
+		return '';
+	}
+}
+
+class CustomerEntity
+{
+	public function getGuest(): bool
+	{
+		return true;
+	}
+}
+
+class GuestAuthenticator
+{
+	public function validate(OrderEntity $order, string $s): void
+	{
+		$isOrderByGuest = $order->getOrderCustomer()?->getCustomer()?->getGuest();
+
+		if (!$isOrderByGuest) {
+			throw new \Exception();
+		}
+
+
+		if (mb_strtolower($s) !== mb_strtolower($order->getOrderCustomer()?->getEmail() ?: '')) {
+			throw new \Exception();
+		}
+	}
+}
+