detect override of deprecated property

Author: Khartir

Diff for: rules.neon

@@ -4,6 +4,8 @@ parameters:
 services:
     -
         class: PHPStan\Rules\Deprecations\DeprecatedClassHelper
+    -
+        class: PHPStan\Rules\Deprecations\OverrideDeprecatedPropertyRule
 
 rules:
 	- PHPStan\Rules\Deprecations\AccessDeprecatedPropertyRule
@@ -22,3 +24,7 @@ rules:
 	- PHPStan\Rules\Deprecations\TypeHintDeprecatedInFunctionSignatureRule
 	- PHPStan\Rules\Deprecations\UsageOfDeprecatedCastRule
 	- PHPStan\Rules\Deprecations\UsageOfDeprecatedTraitRule
+
+conditionalTags:
+    PHPStan\Rules\Deprecations\OverrideDeprecatedPropertyRule:
+        phpstan.rules.rule: %featureToggles.bleedingEdge%

Diff for: src/Rules/Deprecations/OverrideDeprecatedPropertyRule.php

@@ -0,0 +1,60 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Deprecations;
+
+use PhpParser\Node;
+use PhpParser\Node\Stmt\Property;
+use PHPStan\Analyser\Scope;
+use PHPStan\Rules\Rule;
+use function sprintf;
+
+/**
+ * @implements Rule<Property>
+ */
+class OverrideDeprecatedPropertyRule implements Rule
+{
+
+	public function getNodeType(): string
+	{
+		return Property::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		if (DeprecatedScopeHelper::isScopeDeprecated($scope)) {
+			return [];
+		}
+
+		if (!$scope->isInClass()) {
+			return [];
+		}
+
+		$class = $scope->getClassReflection();
+
+		$parents = $class->getParents();
+
+		$propertyName = (string) $node->props[0]->name;
+
+		foreach ($parents as $parent) {
+			if (!$parent->hasProperty($propertyName)) {
+				continue;
+			}
+
+			$parentProperty = $parent->getProperty($propertyName, $scope);
+
+			if (!$parentProperty->isDeprecated()->yes()) {
+				return [];
+			}
+
+			return [sprintf(
+				'Class %s overrides deprecated property %s of class %s.',
+				$class->getName(),
+				$propertyName,
+				$parent->getName()
+			)];
+		}
+
+		return [];
+	}
+
+}

Diff for: tests/Rules/Deprecations/OverrideDeprecatedPropertyRuleTest.php

@@ -0,0 +1,32 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Deprecations;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<OverrideDeprecatedPropertyRule>
+ */
+class OverrideDeprecatedPropertyRuleTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new OverrideDeprecatedPropertyRule();
+	}
+
+	public function testDeprecatedPropertyOverride(): void
+	{
+		$this->analyse(
+			[__DIR__ . '/data/override-deprecated-property.php'],
+			[
+				[
+					'Class OverrideDeprecatedProperty\Child overrides deprecated property foo of class OverrideDeprecatedProperty\Foo.',
+					15,
+				],
+			]
+		);
+	}
+
+}

Diff for: tests/Rules/Deprecations/data/override-deprecated-property.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace OverrideDeprecatedProperty;
+
+class Foo
+{
+	/**
+	 * @deprecated
+	 */
+	public $foo;
+}
+
+class Child extends Foo
+{
+	public $foo;
+}