Add non-regression test for bug 8048

Ensures template type T with class-string parameter is correctly
resolved and does not produce false "Unable to resolve the template
type T" errors.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php

@@ -4070,4 +4070,12 @@ public function testBug11894(): void
 		$this->analyse([__DIR__ . '/data/bug-11894.php'], []);
 	}
 
+	public function testBug8048(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->analyse([__DIR__ . '/data/bug-8048.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/bug-8048.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace Bug8048;
+
+interface CustomResponseInterface
+{
+}
+
+final class CustomResponse implements CustomResponseInterface
+{
+}
+
+final class ApiService
+{
+	/**
+	 * @template T of CustomResponseInterface
+	 * @param class-string<T> $class
+	 * @return T|null
+	 */
+	public function request(string $class): ?CustomResponseInterface
+	{
+		return new CustomResponse();
+	}
+}
+
+final class Consumer
+{
+	public function test(): void
+	{
+		$apiService = new ApiService();
+		$result = $apiService->request(CustomResponse::class);
+	}
+}