Fix segfault

src/Type/IntersectionType.php

@@ -19,6 +19,7 @@
 use PHPStan\Type\Accessory\AccessoryNumericStringType;
 use PHPStan\Type\Accessory\AccessoryType;
 use PHPStan\Type\Accessory\NonEmptyArrayType;
+use PHPStan\Type\Generic\TemplateType;
 use PHPStan\Type\Generic\TemplateTypeMap;
 use PHPStan\Type\Generic\TemplateTypeVariance;
 use function array_map;
@@ -96,7 +97,7 @@ public function isSuperTypeOf(Type $otherType): TrinaryLogic
 
 	public function isSubTypeOf(Type $otherType): TrinaryLogic
 	{
-		if ($otherType instanceof self || $otherType instanceof UnionType) {
+		if (($otherType instanceof self || $otherType instanceof UnionType) && !$otherType instanceof TemplateType) {
 			return $otherType->isSuperTypeOf($this);
 		}
 

tests/PHPStan/Analyser/AnalyserIntegrationTest.php

@@ -535,6 +535,12 @@ public function testBug6375(): void
 		$this->assertNoErrors($errors);
 	}
 
+	public function testBug6501(): void
+	{
+		$errors = $this->runAnalyse(__DIR__ . '/data/bug-6501.php');
+		$this->assertNoErrors($errors);
+	}
+
 	/**
 	 * @param string[]|null $allAnalysedFiles
 	 * @return Error[]

tests/PHPStan/Analyser/data/bug-6501.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Bug6501;
+
+/**
+ * @template T of \stdClass
+ * @template R of \stdClass|\Exception
+ */
+abstract class AbstractWithOptionsHydrator
+{
+	/** @var string */
+	protected const OPTION_OWNER_PROPERTY = '';
+
+	/**
+	 * @param T $entity
+	 *
+	 * @return R
+	 */
+	protected function hydrateOption(\stdClass $entity)
+	{
+		/** @var R $option */
+		$option   = new \stdClass();
+		$callable = [$option, 'set' . static::OPTION_OWNER_PROPERTY];
+		if (!is_callable($callable)) {
+			return $option;
+		}
+
+		call_user_func($callable, $entity);
+
+		return $option;
+	}
+}