Do not report missing implementation abstract method from trait when it's implicitly implemented by enum

Author: ondrejmirtes

src/Rules/Classes/EnumSanityRule.php

@@ -47,20 +47,7 @@ public function processNode(Node $node, Scope $scope): array
 		$errors = [];
 
 		foreach ($enumNode->getMethods() as $methodNode) {
-			if ($methodNode->isAbstract()) {
-				$errors[] = RuleErrorBuilder::message(sprintf(
-					'Enum %s contains abstract method %s().',
-					$classReflection->getDisplayName(),
-					$methodNode->name->name,
-				))
-					->identifier('enum.abstractMethod')
-					->line($methodNode->getStartLine())
-					->nonIgnorable()
-					->build();
-			}
-
 			$lowercasedMethodName = $methodNode->name->toLowerString();
-
 			if ($methodNode->isMagic()) {
 				if ($lowercasedMethodName === '__construct') {
 					$errors[] = RuleErrorBuilder::message(sprintf(

src/Rules/Methods/AbstractMethodInNonAbstractClassRule.php

@@ -7,6 +7,7 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\ShouldNotHappenException;
+use function in_array;
 use function sprintf;
 
 /**
@@ -29,6 +30,18 @@ public function processNode(Node $node, Scope $scope): array
 		$class = $scope->getClassReflection();
 
 		if (!$class->isAbstract() && $node->isAbstract()) {
+			if ($class->isEnum()) {
+				$lowercasedMethodName = $node->name->toLowerString();
+				if ($lowercasedMethodName === 'cases') {
+					return [];
+				}
+				if ($class->isBackedEnum()) {
+					if (in_array($lowercasedMethodName, ['from', 'tryfrom'], true)) {
+						return [];
+					}
+				}
+			}
+
 			$description = $class->getClassTypeDescription();
 			return [
 				RuleErrorBuilder::message(sprintf(

tests/PHPStan/Rules/Classes/EnumSanityRuleTest.php

@@ -24,10 +24,11 @@ public function testRule(): void
 		}
 
 		$expected = [
-			[
+			/*[
+				// reported by AbstractMethodInNonAbstractClassRule
 				'Enum EnumSanity\EnumWithAbstractMethod contains abstract method foo().',
 				7,
-			],
+			],*/
 			[
 				'Enum EnumSanity\EnumWithConstructorAndDestructor contains constructor.',
 				12,
@@ -123,4 +124,30 @@ public function testBug9402(): void
 		]);
 	}
 
+	public function testBug11592(): void
+	{
+		if (PHP_VERSION_ID < 80100) {
+			$this->markTestSkipped('Test requires PHP 8.1');
+		}
+
+		$this->analyse([__DIR__ . '/data/bug-11592.php'], [
+			[
+				'Enum Bug11592\Test2 cannot redeclare native method cases().',
+				22,
+			],
+			[
+				'Enum Bug11592\BackedTest2 cannot redeclare native method cases().',
+				37,
+			],
+			[
+				'Enum Bug11592\BackedTest2 cannot redeclare native method from().',
+				39,
+			],
+			[
+				'Enum Bug11592\BackedTest2 cannot redeclare native method tryFrom().',
+				41,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Classes/data/bug-11592.php

@@ -0,0 +1,47 @@
+<?php // lint >= 8.1
+
+namespace Bug11592;
+
+trait HelloWorld
+{
+	abstract public static function cases(): array;
+
+	abstract public static function from(): self;
+
+	abstract public static function tryFrom(): ?self;
+}
+
+enum Test
+{
+	use HelloWorld;
+}
+
+enum Test2
+{
+
+	abstract public static function cases(): array;
+
+	abstract public static function from(): self;
+
+	abstract public static function tryFrom(): ?self;
+
+}
+
+enum BackedTest: int
+{
+	use HelloWorld;
+}
+
+enum BackedTest2: int
+{
+	abstract public static function cases(): array;
+
+	abstract public static function from(): self;
+
+	abstract public static function tryFrom(): ?self;
+}
+
+enum EnumWithAbstractMethod
+{
+	abstract function foo();
+}

tests/PHPStan/Rules/Methods/AbstractMethodInNonAbstractClassRuleTest.php

@@ -89,4 +89,34 @@ public function testEnum(): void
 		]);
 	}
 
+	public function testBug11592(): void
+	{
+		if (PHP_VERSION_ID < 80100) {
+			$this->markTestSkipped('Test requires PHP 8.1');
+		}
+
+		$this->analyse([__DIR__ . '/../Classes/data/bug-11592.php'], [
+			[
+				'Enum Bug11592\Test contains abstract method from().',
+				9,
+			],
+			[
+				'Enum Bug11592\Test contains abstract method tryFrom().',
+				11,
+			],
+			[
+				'Enum Bug11592\Test2 contains abstract method from().',
+				24,
+			],
+			[
+				'Enum Bug11592\Test2 contains abstract method tryFrom().',
+				26,
+			],
+			[
+				'Enum Bug11592\EnumWithAbstractMethod contains abstract method foo().',
+				46,
+			],
+		]);
+	}
+
 }