Hooked properties cannot be both final and private

Makefile

@@ -101,6 +101,12 @@ lint:
 		--exclude tests/PHPStan/Rules/Properties/data/existing-classes-property-hooks.php \
 		--exclude tests/PHPStan/Rules/Properties/data/set-property-hook-parameter.php \
 		--exclude tests/PHPStan/Rules/Properties/data/overriding-final-property.php \
+		--exclude tests/PHPStan/Rules/Properties/data/private-final-property-hooks.php \
+		--exclude tests/PHPStan/Rules/Properties/data/abstract-final-property-hook.php \
+		--exclude tests/PHPStan/Rules/Properties/data/final-property-hooks-in-interface.php \
+		--exclude tests/PHPStan/Rules/Properties/data/final-property-hooks.php \
+		--exclude tests/PHPStan/Rules/Properties/data/final-properties.php \
+		--exclude tests/PHPStan/Rules/Properties/data/property-in-interface-explicit-abstract.php \
 		src tests
 
 cs:

src/Node/ClassPropertyNode.php

@@ -86,6 +86,11 @@ public function isPrivate(): bool
 		return (bool) ($this->flags & Modifiers::PRIVATE);
 	}
 
+	public function isFinal(): bool
+	{
+		return (bool) ($this->flags & Modifiers::FINAL);
+	}
+
 	public function isStatic(): bool
 	{
 		return (bool) ($this->flags & Modifiers::STATIC);

src/Php/PhpVersion.php

@@ -357,6 +357,11 @@ public function supportsPropertyHooks(): bool
 		return $this->versionId >= 80400;
 	}
 
+	public function supportsFinalProperties(): bool
+	{
+		return $this->versionId >= 80400;
+	}
+
 	public function supportsAsymmetricVisibility(): bool
 	{
 		return $this->versionId >= 80400;

src/Rules/Properties/PropertiesInInterfaceRule.php

@@ -32,7 +32,7 @@ public function processNode(Node $node, Scope $scope): array
 
 		if (!$this->phpVersion->supportsPropertyHooks()) {
 			return [
-				RuleErrorBuilder::message('Interfaces cannot include properties.')
+				RuleErrorBuilder::message('Interfaces can include properties only on PHP 8.4 and later.')
 					->nonIgnorable()
 					->identifier('property.inInterface')
 					->build(),
@@ -75,6 +75,37 @@ public function processNode(Node $node, Scope $scope): array
 			];
 		}
 
+		if ($node->isAbstract()) {
+			return [
+				RuleErrorBuilder::message('Property in interface cannot be explicitly abstract.')
+					->nonIgnorable()
+					->identifier('property.abstractInInterface')
+					->build(),
+			];
+		}
+
+		if ($node->isFinal()) {
+			return [
+				RuleErrorBuilder::message('Interfaces cannot include final properties.')
+					->nonIgnorable()
+					->identifier('property.finalInInterface')
+					->build(),
+			];
+		}
+
+		foreach ($node->getHooks() as $hook) {
+			if (!$hook->isFinal()) {
+				continue;
+			}
+
+			return [
+				RuleErrorBuilder::message('Property hook cannot be both abstract and final.')
+					->nonIgnorable()
+					->identifier('property.hookedAbstractFinal')
+					->build(),
+			];
+		}
+
 		if ($this->hasAnyHookBody($node)) {
 			return [
 				RuleErrorBuilder::message('Interfaces cannot include property hooks with bodies.')

src/Rules/Properties/PropertyInClassRule.php

@@ -32,6 +32,18 @@ public function processNode(Node $node, Scope $scope): array
 			return [];
 		}
 
+		if (
+			$node->isFinal()
+			&& !$this->phpVersion->supportsFinalProperties()
+		) {
+			return [
+				RuleErrorBuilder::message('Final properties are supported only on PHP 8.4 and later.')
+					->nonIgnorable()
+					->identifier('property.final')
+					->build(),
+			];
+		}
+
 		if (!$this->phpVersion->supportsPropertyHooks()) {
 			if ($node->hasHooks()) {
 				return [
@@ -81,6 +93,58 @@ public function processNode(Node $node, Scope $scope): array
 			];
 		}
 
+		if ($node->isPrivate()) {
+			if ($node->isFinal()) {
+				return [
+					RuleErrorBuilder::message('Property cannot be both final and private.')
+						->nonIgnorable()
+						->identifier('property.finalPrivate')
+						->build(),
+				];
+			}
+
+			foreach ($node->getHooks() as $hook) {
+				if (!$hook->isFinal()) {
+					continue;
+				}
+
+				return [
+					RuleErrorBuilder::message('Private property cannot have a final hook.')
+						->nonIgnorable()
+						->identifier('property.finalPrivateHook')
+						->build(),
+				];
+			}
+		}
+
+		if ($node->isAbstract()) {
+			if ($node->isFinal()) {
+				return [
+					RuleErrorBuilder::message('Property cannot be both abstract and final.')
+						->nonIgnorable()
+						->identifier('property.abstractFinal')
+						->build(),
+				];
+			}
+
+			foreach ($node->getHooks() as $hook) {
+				if ($hook->body !== null) {
+					continue;
+				}
+
+				if (!$hook->isFinal()) {
+					continue;
+				}
+
+				return [
+					RuleErrorBuilder::message('Property cannot be both abstract and final.')
+						->nonIgnorable()
+						->identifier('property.abstractFinal')
+						->build(),
+				];
+			}
+		}
+
 		if ($node->isReadOnly()) {
 			if ($node->hasHooks()) {
 				return [

tests/PHPStan/Rules/Properties/PropertiesInInterfaceRuleTest.php

@@ -29,17 +29,21 @@ public function testPhp83AndPropertiesInInterface(): void
 
 		$this->analyse([__DIR__ . '/data/properties-in-interface.php'], [
 			[
-				'Interfaces cannot include properties.',
+				'Interfaces can include properties only on PHP 8.4 and later.',
 				7,
 			],
 			[
-				'Interfaces cannot include properties.',
+				'Interfaces can include properties only on PHP 8.4 and later.',
 				9,
 			],
 			[
-				'Interfaces cannot include properties.',
+				'Interfaces can include properties only on PHP 8.4 and later.',
 				11,
 			],
+			[
+				'Interfaces can include properties only on PHP 8.4 and later.',
+				13,
+			],
 		]);
 	}
 
@@ -54,11 +58,11 @@ public function testPhp83AndPropertyHooksInInterface(): void
 
 		$this->analyse([__DIR__ . '/data/property-hooks-in-interface.php'], [
 			[
-				'Interfaces cannot include properties.',
+				'Interfaces can include properties only on PHP 8.4 and later.',
 				7,
 			],
 			[
-				'Interfaces cannot include properties.',
+				'Interfaces can include properties only on PHP 8.4 and later.',
 				9,
 			],
 		]);
@@ -79,6 +83,10 @@ public function testPhp84AndPropertiesInInterface(): void
 				'Interfaces can only include hooked properties.',
 				11,
 			],
+			[
+				'Interfaces can only include hooked properties.',
+				13,
+			],
 		]);
 	}
 
@@ -140,6 +148,50 @@ public function testPhp84AndReadonlyPropertyHooksInInterface(): void
 		]);
 	}
 
+	public function testPhp84AndFinalPropertyHooksInInterface(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4 or later.');
+		}
+
+		$this->analyse([__DIR__ . '/data/final-property-hooks-in-interface.php'], [
+			[
+				'Interfaces cannot include final properties.',
+				7,
+			],
+			[
+				'Interfaces cannot include final properties.',
+				9,
+			],
+			[
+				'Interfaces cannot include final properties.',
+				11,
+			],
+			[
+				'Property hook cannot be both abstract and final.',
+				13,
+			],
+			[
+				'Property hook cannot be both abstract and final.',
+				17,
+			],
+		]);
+	}
+
+	public function testPhp84AndExplicitAbstractProperty(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4 or later.');
+		}
+
+		$this->analyse([__DIR__ . '/data/property-in-interface-explicit-abstract.php'], [
+			[
+				'Property in interface cannot be explicitly abstract.',
+				8,
+			],
+		]);
+	}
+
 	public function testPhp84AndStaticHookedPropertyInInterface(): void
 	{
 		if (PHP_VERSION_ID < 80400) {

tests/PHPStan/Rules/Properties/PropertyInClassRuleTest.php

@@ -213,4 +213,101 @@ public function testPhp84AndStaticHookedProperties(): void
 		]);
 	}
 
+	public function testPhp84AndPrivateFinalHookedProperties(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4 or later.');
+		}
+
+		$this->analyse([__DIR__ . '/data/private-final-property-hooks.php'], [
+			[
+				'Property cannot be both final and private.',
+				7,
+			],
+			[
+				'Private property cannot have a final hook.',
+				11,
+			],
+		]);
+	}
+
+	public function testPhp84AndAbstractFinalHookedProperties(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4 or later.');
+		}
+
+		$this->analyse([__DIR__ . '/data/abstract-final-property-hook.php'], [
+			[
+				'Property cannot be both abstract and final.',
+				7,
+			],
+		]);
+	}
+
+	public function testPhp84AndAbstractFinalHookedPropertiesParseError(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4 or later.');
+		}
+
+		// errors when parsing with php-parser, see https://github.com/nikic/PHP-Parser/issues/1071
+		$this->analyse([__DIR__ . '/data/abstract-final-property-hook-parse-error.php'], [
+			[
+				'Cannot use the final modifier on an abstract class member on line 7',
+				7,
+			],
+		]);
+	}
+
+	public function testPhp84FinalProperties(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4 or later.');
+		}
+
+		$this->analyse([__DIR__ . '/data/final-properties.php'], [
+			[
+				'Property cannot be both final and private.',
+				7,
+			],
+		]);
+	}
+
+	public function testBeforePhp84FinalProperties(): void
+	{
+		if (PHP_VERSION_ID >= 80400) {
+			$this->markTestSkipped('Test requires PHP 8.3 or earlier.');
+		}
+
+		$this->analyse([__DIR__ . '/data/final-properties.php'], [
+			[
+				'Final properties are supported only on PHP 8.4 and later.',
+				7,
+			],
+			[
+				'Final properties are supported only on PHP 8.4 and later.',
+				8,
+			],
+			[
+				'Final properties are supported only on PHP 8.4 and later.',
+				9,
+			],
+		]);
+	}
+
+	public function testPhp84FinalPropertyHooks(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4 or later.');
+		}
+
+		$this->analyse([__DIR__ . '/data/final-property-hooks.php'], [
+			[
+				'Cannot use the final modifier on an abstract class member on line 19',
+				19,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Properties/data/abstract-final-property-hook-parse-error.php

@@ -0,0 +1,10 @@
+<?php // lint >= 8.4
+
+namespace AbstractFinalHookParseError;
+
+abstract class User
+{
+	final abstract public string $bar {
+		get;
+	}
+}

tests/PHPStan/Rules/Properties/data/abstract-final-property-hook.php

@@ -0,0 +1,15 @@
+<?php // lint >= 8.4
+
+namespace AbstractFinalHook;
+
+abstract class User
+{
+	abstract public string $foo {
+		final get;
+	}
+}
+
+abstract class Foo
+{
+	abstract public int $i { final get { return 1;} set; }
+}