Interfaces cannot include final properties

Author: staabm

Makefile

@@ -103,6 +103,8 @@ lint:
 		--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 \
 		src tests
 

src/Rules/Properties/PropertiesInInterfaceRule.php

@@ -75,6 +75,15 @@ public function processNode(Node $node, Scope $scope): array
 			];
 		}
 
+		if ($node->isFinal()) {
+			return [
+				RuleErrorBuilder::message('Interfaces cannot include final properties.')
+					->nonIgnorable()
+					->identifier('property.finalInInterface')
+					->build(),
+			];
+		}
+
 		if ($this->hasAnyHookBody($node)) {
 			return [
 				RuleErrorBuilder::message('Interfaces cannot include property hooks with bodies.')

tests/PHPStan/Rules/Properties/PropertiesInInterfaceRuleTest.php

@@ -40,6 +40,10 @@ public function testPhp83AndPropertiesInInterface(): void
 				'Interfaces cannot include properties.',
 				11,
 			],
+			[
+				'Interfaces cannot include properties.',
+				13,
+			],
 		]);
 	}
 
@@ -79,6 +83,10 @@ public function testPhp84AndPropertiesInInterface(): void
 				'Interfaces can only include hooked properties.',
 				11,
 			],
+			[
+				'Interfaces can only include hooked properties.',
+				13,
+			],
 		]);
 	}
 
@@ -140,6 +148,28 @@ 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,
+			],
+		]);
+	}
+
 	public function testPhp84AndStaticHookedPropertyInInterface(): void
 	{
 		if (PHP_VERSION_ID < 80400) {

tests/PHPStan/Rules/Properties/PropertyInClassRuleTest.php

@@ -281,4 +281,18 @@ public function testBeforePhp84FinalProperties(): void
 		]);
 	}
 
+	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/final-property-hooks-in-interface.php

@@ -0,0 +1,12 @@
+<?php declare(strict_types=1);
+
+namespace FinalPropertyHooksInInterface;
+
+interface HelloWorld
+{
+	public final string $firstName { get; set; }
+
+	public final string $middleName { get; }
+
+	public final string $lastName { set; }
+}

tests/PHPStan/Rules/Properties/data/final-property-hooks.php

@@ -0,0 +1,28 @@
+<?php declare(strict_types=1);
+
+namespace FinalPropertyHooks;
+
+class HelloWorld
+{
+	public final string $firstName {
+		get => $this->firstName;
+		set => $this->firstName;
+	}
+
+	public final string $middleName { get => $this->middleName; }
+
+	public final string $lastName { set => $this->lastName; }
+}
+
+abstract class HiWorld
+{
+	public abstract final string $firstName { get { return 'jake'; } set; }
+}
+
+final class GoodMorningWorld
+{
+	public string $firstName {
+		get => $this->firstName;
+		set => $this->firstName;
+	}
+}

tests/PHPStan/Rules/Properties/data/properties-in-interface.php

@@ -9,4 +9,6 @@ interface HelloWorld
     public \DateTimeInterface $dateTime;
 
     public static \Closure $callable;
+
+    public final \DateTime $finalProperty;
 }