Improve

Author: VincentLanglet

src/Type/Php/IsAFunctionTypeSpecifyingHelper.php

@@ -47,14 +47,18 @@ static function (Type $type, callable $traverse) use ($objectOrClassType, $objec
 				}
 				if ($type instanceof ConstantStringType) {
 					if (!$allowSameClass) {
-						// For objectType we cannot be sure since 'Foo' is used for both
-						// - the Foo class
-						// - a child of foo class
-						if (
-							$objectOrClassTypeClassNames === [$type->getValue()]
-							&& $objectOrClassType->isString()->yes()
-						) {
-							return new NeverType();
+						if ($objectOrClassTypeClassNames === [$type->getValue()]) {
+							$isSameClass = true;
+							foreach ($objectOrClassType->getObjectClassReflections() as $classReflection) {
+								if (!$classReflection->isFinal()) {
+									$isSameClass = false;
+									break;
+								}
+							}
+
+							if ($isSameClass) {
+								return new NeverType();
+							}
 						}
 
 						if (

tests/PHPStan/Analyser/nsrt/bug-6305.php

@@ -15,5 +15,5 @@ class B extends A {}
 }
 
 if (is_subclass_of($b, B::class)) {
-	assertType('Bug6305Types\B', $b); // Could be NEVER
+	assertType('*NEVER*', $b);
 }

tests/PHPStan/Rules/Comparison/ImpossibleCheckTypeFunctionCallRuleTest.php

@@ -393,10 +393,10 @@ public function testBug6305(): void
 				'Call to function is_subclass_of() with Bug6305\B and \'Bug6305\\\A\' will always evaluate to true.',
 				11,
 			],
-			// [
-			//	'Call to function is_subclass_of() with Bug6305\B and \'Bug6305\\\B\' will always evaluate to false.',
-			//	14,
-			// ],
+			[
+				'Call to function is_subclass_of() with Bug6305\B and \'Bug6305\\\B\' will always evaluate to false.',
+				14,
+			],
 		]);
 	}