Add test for identical description disambiguation with invariant template types

Cover the second code path in VerbosityLevel::getRecommendedLevelByType()
where containsInvariantTemplateType is true. The test uses a generic
Container<T> (invariant template) wrapping template types from different
scopes that would otherwise produce identical descriptions.

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

Author: phpstan-bot

tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php

@@ -423,4 +423,16 @@ public function testBug13453(): void
 		]);
 	}
 
+	public function testBug13453Invariant(): void
+	{
+		$this->checkNullables = true;
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-13453-invariant.php'], [
+			[
+				'Function Bug13453Invariant\run() should return Bug13453Invariant\Container<T of Bug13453Invariant\ResultA (function Bug13453Invariant\run(), argument)> but returns Bug13453Invariant\Container<T of Bug13453Invariant\ResultA (class Bug13453Invariant\I, parameter)>.',
+				37,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Functions/data/bug-13453-invariant.php

@@ -0,0 +1,38 @@
+<?php // lint >= 8.3
+
+declare(strict_types = 1);
+
+namespace Bug13453Invariant;
+
+/** @template T */
+class Container {
+	/** @param T $value */
+	public function __construct(public mixed $value) {}
+}
+
+class ResultA {
+	public function __construct(public string $value) {}
+}
+
+class ResultB extends ResultA {}
+
+/** @template T of ResultA */
+interface I {
+	/** @var class-string<T> */
+	public const string ResultType = ResultA::class;
+}
+
+/** @template-implements I<ResultB> */
+class In implements I {
+	public const string ResultType = ResultB::class;
+}
+
+/**
+ * @template T of ResultA
+ * @param I<T> $in
+ * @return Container<T>
+ */
+function run(I $in): Container {
+	$value = 'abc';
+	return new Container(new ($in::ResultType)($value));
+}