Do not report abstract interface methods provided by a non-abstract built-in parent class in MissingMethodImplementationRule

src/Rules/Methods/MissingMethodImplementationRule.php

@@ -7,6 +7,7 @@
 use PHPStan\BetterReflection\Reflector\Exception\IdentifierNotFound;
 use PHPStan\DependencyInjection\RegisteredRule;
 use PHPStan\Node\InClassNode;
+use PHPStan\Reflection\ClassReflection;
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use function sprintf;
@@ -47,6 +48,17 @@ public function processNode(Node $node, Scope $scope): array
 
 			$declaringClass = $method->getDeclaringClass();
 
+			if (
+				$declaringClass->isInterface()
+				&& $this->isProvidedByBuiltinAncestor($classReflection, $declaringClass->getName())
+			) {
+				// A non-abstract built-in class implementing the interface always
+				// provides its methods at runtime, even when a stub reports one as
+				// abstract because it is version-gated (e.g. IntlBreakIterator +
+				// IteratorAggregate::getIterator(), SimpleXMLElement + RecursiveIterator).
+				continue;
+			}
+
 			$classLikeDescription = 'Non-abstract class';
 			if ($classReflection->isEnum()) {
 				$classLikeDescription = 'Enum';
@@ -65,4 +77,21 @@ public function processNode(Node $node, Scope $scope): array
 		return $messages;
 	}
 
+	private function isProvidedByBuiltinAncestor(ClassReflection $classReflection, string $interfaceName): bool
+	{
+		foreach ($classReflection->getParents() as $parent) {
+			if (!$parent->isBuiltin()) {
+				continue;
+			}
+			if ($parent->isAbstract()) {
+				continue;
+			}
+			if ($parent->implementsInterface($interfaceName)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
 }

tests/PHPStan/Rules/Methods/MissingMethodImplementationRulePhp74Test.php

@@ -0,0 +1,31 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Methods;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<MissingMethodImplementationRule>
+ */
+class MissingMethodImplementationRulePhp74Test extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new MissingMethodImplementationRule();
+	}
+
+	public function testBug14964(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-14964.php'], []);
+	}
+
+	public static function getAdditionalConfigFiles(): array
+	{
+		return [
+			__DIR__ . '/data/missing-method-impl-php74.neon',
+		];
+	}
+
+}

tests/PHPStan/Rules/Methods/data/bug-14964.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Bug14964;
+
+final class XmlHelper extends \SimpleXMLElement
+{
+}
+
+final class MyBreakIterator extends \IntlBreakIterator
+{
+}

tests/PHPStan/Rules/Methods/data/missing-method-impl-php74.neon

@@ -0,0 +1,2 @@
+parameters:
+    phpVersion: 70400