Add MethodVisibilityOverrideRule

rules.neon

@@ -20,6 +20,7 @@ rules:
 	- PHPStan\Rules\DisallowedConstructs\DisallowedImplicitArrayCreationRule
 	- PHPStan\Rules\DisallowedConstructs\DisallowedShortTernaryRule
 	- PHPStan\Rules\ForeachLoop\OverwriteVariablesWithForeachRule
+	- PHPStan\Rules\Methods\MethodVisibilityOverrideRule
 	- PHPStan\Rules\Methods\WrongCaseOfInheritedMethodRule
 	- PHPStan\Rules\Operators\OperandInArithmeticPostDecrementRule
 	- PHPStan\Rules\Operators\OperandInArithmeticPostIncrementRule

src/Rules/Methods/MethodVisibilityOverrideRule.php

@@ -0,0 +1,59 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Methods;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\Node\InClassMethodNode;
+use PHPStan\Reflection\MethodReflection;
+use PHPStan\Rules\Rule;
+
+/**
+ * @implements Rule<InClassMethodNode>
+ */
+class MethodVisibilityOverrideRule implements Rule
+{
+
+	public function getNodeType(): string
+	{
+		return InClassMethodNode::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		$methodReflection = $scope->getFunction();
+		if (!$methodReflection instanceof MethodReflection) {
+			return [];
+		}
+
+		$methodName = $methodReflection->getName();
+		if (strtolower($methodName) === '__construct') {
+			return [];
+		}
+
+		$declaringClass = $methodReflection->getDeclaringClass();
+		$parentClass = $declaringClass->getParentClass();
+
+		if ($parentClass === false) {
+			return [];
+		}
+
+		if (!$parentClass->hasNativeMethod($methodName)) {
+			return [];
+		}
+
+		$parentMethodReflection = $parentClass->getNativeMethod($methodName);
+
+		if (!$parentMethodReflection->isPrivate() && !$parentMethodReflection->isPublic() && $methodReflection->isPublic()) {
+			$message = sprintf(
+				'Method %s::%s() overrides visibility from protected to public',
+				$declaringClass->getDisplayName(),
+				$methodName,
+			);
+			return [$message];
+		}
+
+		return [];
+	}
+
+}

tests/Rules/Methods/MethodVisibilityOverrideRuleTest.php

@@ -0,0 +1,27 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Methods;
+
+class MethodVisibilityOverrideRuleTest extends \PHPStan\Testing\RuleTestCase
+{
+
+	protected function getRule(): \PHPStan\Rules\Rule
+	{
+		return new MethodVisibilityOverrideRule();
+	}
+
+	public function testRule(): void
+	{
+		$this->analyse([__DIR__ . '/data/visibility-override.php'], [
+			[
+				'Method MethodVisibilityOverride\\SubClass::foo3() overrides visibility from protected to public',
+				63,
+			],
+			[
+				'Method MethodVisibilityOverride\\OtherSubSubClass::foo3() overrides visibility from protected to public',
+				93,
+			],
+		]);
+	}
+
+}

tests/Rules/Methods/data/visibility-override.php

@@ -0,0 +1,98 @@
+<?php
+
+namespace MethodVisibilityOverride;
+
+class BaseClass
+{
+
+	protected function __construct()
+	{
+
+	}
+
+	public function foo1()
+	{
+
+	}
+
+	protected function foo2()
+	{
+
+	}
+
+	protected function foo3()
+	{
+
+	}
+
+	private function foo4()
+	{
+
+	}
+
+	private function foo5()
+	{
+
+	}
+
+	private function foo6()
+	{
+
+	}
+
+}
+
+class SubClass extends BaseClass
+{
+
+	public function __construct()
+	{
+
+	}
+
+	public function foo1()
+	{
+
+	}
+
+	protected function foo2()
+	{
+
+	}
+
+	public function foo3()
+	{
+
+	}
+
+	public function foo4()
+	{
+
+	}
+
+	protected function foo5()
+	{
+
+	}
+
+	protected function foo6()
+	{
+
+	}
+
+}
+
+class OtherSubClass extends BaseClass
+{
+
+}
+
+class OtherSubSubClass extends OtherSubClass
+{
+
+	public function foo3()
+	{
+
+	}
+
+}