Add rule test for undefined method calls on union template return types

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: phpstan-bot

tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php

@@ -987,6 +987,23 @@ public function testBug14720(): void
 		$this->analyse([__DIR__ . '/data/bug-14720.php'], []);
 	}
 
+	public function testBug2579(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->analyse([__DIR__ . '/data/bug-2579.php'], [
+			[
+				'Call to an undefined method Bug2579Methods\A1::bar().',
+				30,
+			],
+			[
+				'Call to an undefined method Bug2579Methods\B1::foo().',
+				31,
+			],
+		]);
+	}
+
 	public function testClosureBind(): void
 	{
 		$this->checkThisOnly = false;

tests/PHPStan/Rules/Methods/data/bug-2579.php

@@ -0,0 +1,32 @@
+<?php declare(strict_types = 1);
+
+namespace Bug2579Methods;
+
+class A {}
+class B {}
+class A1 extends A {
+	public function foo(): void {}
+}
+class B1 extends B {
+	public function bar(): void {}
+}
+
+/**
+ * @template T1 of A
+ * @template T2 of B
+ * @param T1|T2 $type
+ * @return T1|T2
+ */
+function f(object $type)
+{
+	return new $type();
+}
+
+function test(): void
+{
+	(f(new A1()))->foo(); // should pass
+	(f(new B1()))->bar(); // should pass
+
+	(f(new A1()))->bar(); // should fail
+	(f(new B1()))->foo(); // should fail
+}