Fix SimpleXMLElement::xpath return type

Author: VincentLanglet

src/Type/Php/SimpleXMLElementXpathMethodReturnTypeExtension.php

@@ -6,9 +6,9 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Reflection\MethodReflection;
-use PHPStan\Type\ArrayType;
+use PHPStan\Reflection\ParametersAcceptorSelector;
+use PHPStan\Type\Constant\ConstantBooleanType;
 use PHPStan\Type\DynamicMethodReturnTypeExtension;
-use PHPStan\Type\MixedType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
@@ -31,11 +31,12 @@ public function isMethodSupported(MethodReflection $methodReflection): bool
 
 	public function getTypeFromMethodCall(MethodReflection $methodReflection, MethodCall $methodCall, Scope $scope): ?Type
 	{
-		if (!isset($methodCall->getArgs()[0])) {
+		$args = $methodCall->getArgs();
+		if (!isset($args[0])) {
 			return null;
 		}
 
-		$argType = $scope->getType($methodCall->getArgs()[0]->value);
+		$argType = $scope->getType($args[0]->value);
 
 		$xmlElement = new SimpleXMLElement('<foo />');
 
@@ -53,7 +54,9 @@ public function getTypeFromMethodCall(MethodReflection $methodReflection, Method
 			return null;
 		}
 
-		return new ArrayType(new MixedType(), $scope->getType($methodCall->var));
+		$variant = ParametersAcceptorSelector::selectFromArgs($scope, $args, $methodReflection->getVariants());
+
+		return TypeCombinator::remove($variant->getReturnType(), new ConstantBooleanType(false));
 	}
 
 }

tests/PHPStan/Analyser/LegacyNodeScopeResolverTest.php

@@ -3144,7 +3144,7 @@ public static function dataBinaryOperations(): array
 				'$simpleXMLWritingXML',
 			],
 			[
-				'array<SimpleXMLElement>',
+				'array<SimpleXMLElement>|null',
 				'$simpleXMLRightXpath',
 			],
 			[

tests/PHPStan/Analyser/nsrt/bug-9714.php

@@ -10,7 +10,6 @@ public function exampleFunction(): void
 	{
 		$xml = new \SimpleXmlElement('');
 		$elements = $xml->xpath('//data');
-		assertType('array<SimpleXmlElement>', $elements);
+		assertType('array<SimpleXmlElement>|null', $elements);
 	}
 }
-