Bleeding edge - check classes extending @final classes

conf/bleedingEdge.neon

@@ -23,5 +23,6 @@ parameters:
 		neverInGenericReturnType: true
 		validateOverridingMethodsInStubs: true
 		crossCheckInterfaces: true
+		finalByPhpDocTag: true
 	stubFiles:
 		- ../stubs/arrayFunctions.stub

conf/config.level0.neon

@@ -42,7 +42,6 @@ rules:
 	- PHPStan\Rules\Classes\DuplicateDeclarationRule
 	- PHPStan\Rules\Classes\ExistingClassesInClassImplementsRule
 	- PHPStan\Rules\Classes\ExistingClassesInInterfaceExtendsRule
-	- PHPStan\Rules\Classes\ExistingClassInClassExtendsRule
 	- PHPStan\Rules\Classes\ExistingClassInTraitUseRule
 	- PHPStan\Rules\Classes\InstantiationRule
 	- PHPStan\Rules\Classes\InvalidPromotedPropertiesRule
@@ -98,6 +97,13 @@ services:
 	-
 		class: PHPStan\Rules\Api\PhpStanNamespaceIn3rdPartyPackageRule
 
+	-
+		class: PHPStan\Rules\Classes\ExistingClassInClassExtendsRule
+		arguments:
+			checkFinalByPhpDocTag: %featureToggles.finalByPhpDocTag%
+		tags:
+			- phpstan.rules.rule
+
 	-
 		class: PHPStan\Rules\Classes\ExistingClassInInstanceOfRule
 		tags:

conf/config.neon

@@ -46,6 +46,7 @@ parameters:
 		neverInGenericReturnType: false
 		validateOverridingMethodsInStubs: false
 		crossCheckInterfaces: false
+		finalByPhpDocTag: false
 	fileExtensions:
 		- php
 	checkAlwaysTrueCheckTypeFunctionCall: false
@@ -219,7 +220,8 @@ parametersSchema:
 		deepInspectTypes: bool(),
 		neverInGenericReturnType: bool(),
 		validateOverridingMethodsInStubs: bool(),
-		crossCheckInterfaces: bool()
+		crossCheckInterfaces: bool(),
+		finalByPhpDocTag: bool()
 	])
 	fileExtensions: listOf(string())
 	checkAlwaysTrueCheckTypeFunctionCall: bool()

src/Rules/Classes/ExistingClassInClassExtendsRule.php

@@ -19,13 +19,17 @@ class ExistingClassInClassExtendsRule implements \PHPStan\Rules\Rule
 
 	private ReflectionProvider $reflectionProvider;
 
+	private bool $checkFinalByPhpDocTag;
+
 	public function __construct(
 		ClassCaseSensitivityCheck $classCaseSensitivityCheck,
-		ReflectionProvider $reflectionProvider
+		ReflectionProvider $reflectionProvider,
+		bool $checkFinalByPhpDocTag = false
 	)
 	{
 		$this->classCaseSensitivityCheck = $classCaseSensitivityCheck;
 		$this->reflectionProvider = $reflectionProvider;
+		$this->checkFinalByPhpDocTag = $checkFinalByPhpDocTag;
 	}
 
 	public function getNodeType(): string
@@ -72,6 +76,12 @@ public function processNode(Node $node, Scope $scope): array
 					$currentClassName !== null ? sprintf('Class %s', $currentClassName) : 'Anonymous class',
 					$extendedClassName
 				))->nonIgnorable()->build();
+			} elseif ($this->checkFinalByPhpDocTag && $reflection->isFinal()) {
+				$messages[] = RuleErrorBuilder::message(sprintf(
+					'%s extends @final class %s.',
+					$currentClassName !== null ? sprintf('Class %s', $currentClassName) : 'Anonymous class',
+					$extendedClassName
+				))->build();
 			}
 		}
 

tests/PHPStan/Rules/Classes/ExistingClassInClassExtendsRuleTest.php

@@ -16,7 +16,8 @@ protected function getRule(): Rule
 		$broker = $this->createReflectionProvider();
 		return new ExistingClassInClassExtendsRule(
 			new ClassCaseSensitivityCheck($broker),
-			$broker
+			$broker,
+			true
 		);
 	}
 
@@ -27,6 +28,10 @@ public function testRule(): void
 				'Class ExtendsImplements\Foo referenced with incorrect case: ExtendsImplements\FOO.',
 				15,
 			],
+			[
+				'Class ExtendsImplements\ExtendsFinalWithAnnotation extends @final class ExtendsImplements\FinalWithAnnotation.',
+				43,
+			],
 		]);
 	}
 
@@ -61,4 +66,14 @@ public function testRuleExtendsError(): void
 		]);
 	}
 
+	public function testFinalByTag(): void
+	{
+		$this->analyse([__DIR__ . '/data/extends-final-by-tag.php'], [
+			[
+				'Class ExtendsFinalByTag\Bar2 extends @final class ExtendsFinalByTag\Bar.',
+				21,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Classes/data/extends-final-by-tag.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace ExtendsFinalByTag;
+
+class Foo
+{
+
+}
+
+/** @final */
+class Bar
+{
+
+}
+
+class Foo2 extends Foo
+{
+
+}
+
+class Bar2 extends Bar
+{
+
+}