diff --git a/src/PhpDoc/StubValidator.php b/src/PhpDoc/StubValidator.php
index b8396455d8..190d3e296c 100644
--- a/src/PhpDoc/StubValidator.php
+++ b/src/PhpDoc/StubValidator.php
@@ -201,7 +201,7 @@ private function getRuleRegistry(Container $container): RuleRegistry
 				$container->getParameter('featureToggles')['invalidPhpDocTagLine'],
 			),
 			new IncompatibleParamImmediatelyInvokedCallableRule($fileTypeMapper),
-			new IncompatibleSelfOutTypeRule(),
+			new IncompatibleSelfOutTypeRule($unresolvableTypeHelper),
 			new IncompatibleClassConstantPhpDocTypeRule($genericObjectTypeCheck, $unresolvableTypeHelper),
 			new InvalidThrowsPhpDocValueRule($fileTypeMapper),
 
diff --git a/src/Rules/PhpDoc/IncompatibleSelfOutTypeRule.php b/src/Rules/PhpDoc/IncompatibleSelfOutTypeRule.php
index b3092b7a4a..e81665cf8b 100644
--- a/src/Rules/PhpDoc/IncompatibleSelfOutTypeRule.php
+++ b/src/Rules/PhpDoc/IncompatibleSelfOutTypeRule.php
@@ -17,6 +17,10 @@
 final class IncompatibleSelfOutTypeRule implements Rule
 {
 
+	public function __construct(private UnresolvableTypeHelper $unresolvableTypeHelper)
+	{
+	}
+
 	public function getNodeType(): string
 	{
 		return InClassMethodNode::class;
@@ -39,7 +43,7 @@ public function processNode(Node $node, Scope $scope): array
 			$errors[] = RuleErrorBuilder::message(sprintf(
 				'Self-out type %s of method %s::%s is not subtype of %s.',
 				$selfOutType->describe(VerbosityLevel::precise()),
-				$classReflection->getName(),
+				$classReflection->getDisplayName(),
 				$method->getName(),
 				$classType->describe(VerbosityLevel::precise()),
 			))->identifier('selfOut.type')->build();
@@ -51,6 +55,14 @@ public function processNode(Node $node, Scope $scope): array
 				->build();
 		}
 
+		if ($this->unresolvableTypeHelper->containsUnresolvableType($selfOutType)) {
+			$errors[] = RuleErrorBuilder::message(sprintf(
+				'PHPDoc tag @phpstan-self-out for method %s::%s() contains unresolvable type.',
+				$classReflection->getDisplayName(),
+				$method->getName(),
+			))->identifier('parameter.unresolvableType')->build();
+		}
+
 		return $errors;
 	}
 
diff --git a/tests/PHPStan/Rules/PhpDoc/IncompatibleSelfOutTypeRuleTest.php b/tests/PHPStan/Rules/PhpDoc/IncompatibleSelfOutTypeRuleTest.php
index dae30a1039..efb2481bb6 100644
--- a/tests/PHPStan/Rules/PhpDoc/IncompatibleSelfOutTypeRuleTest.php
+++ b/tests/PHPStan/Rules/PhpDoc/IncompatibleSelfOutTypeRuleTest.php
@@ -13,7 +13,7 @@ class IncompatibleSelfOutTypeRuleTest extends RuleTestCase
 
 	protected function getRule(): Rule
 	{
-		return new IncompatibleSelfOutTypeRule();
+		return new IncompatibleSelfOutTypeRule(new UnresolvableTypeHelper());
 	}
 
 	public function testRule(): void
@@ -31,6 +31,14 @@ public function testRule(): void
 				'PHPDoc tag @phpstan-self-out is not supported above static method IncompatibleSelfOutType\Foo::selfOutStatic().',
 				38,
 			],
+			[
+				'PHPDoc tag @phpstan-self-out for method IncompatibleSelfOutType\Foo::doFoo() contains unresolvable type.',
+				46,
+			],
+			[
+				'PHPDoc tag @phpstan-self-out for method IncompatibleSelfOutType\Foo::doBar() contains unresolvable type.',
+				54,
+			],
 		]);
 	}
 
diff --git a/tests/PHPStan/Rules/PhpDoc/data/incompatible-self-out-type.php b/tests/PHPStan/Rules/PhpDoc/data/incompatible-self-out-type.php
index 018b6b1c98..6cf1e7057a 100644
--- a/tests/PHPStan/Rules/PhpDoc/data/incompatible-self-out-type.php
+++ b/tests/PHPStan/Rules/PhpDoc/data/incompatible-self-out-type.php
@@ -40,4 +40,20 @@ public static function selfOutStatic(): void
 
 	}
 
+	/**
+	 * @phpstan-self-out int&string
+	 */
+	public function doFoo(): void
+	{
+
+	}
+
+	/**
+	 * @phpstan-self-out self<int&string>
+	 */
+	public function doBar(): void
+	{
+
+	}
+
 }