Detect wrong case in name of an inherited method

README.md

@@ -18,6 +18,7 @@
 * Disallow `empty()` - it's a very loose comparison (see [manual](https://secure.php.net/manual/en/function.empty.php)), it's recommended to use more strict one.
 * Always true `instanceof`, type-checking `is_*` functions and strict comparisons `===`/`!==`. These checks can be turned off by setting `checkAlwaysTrueInstanceof`/`checkAlwaysTrueCheckTypeFunctionCall`/`checkAlwaysTrueStrictComparison` to false.
 * Correct case for referenced and called function names.
+* Correct case for inherited and implemented method names.
 
 Additional rules are coming in subsequent releases!
 

rules.neon

@@ -13,6 +13,24 @@ rules:
 	- PHPStan\Rules\BooleansInConditions\BooleanInIfConditionRule
 	- PHPStan\Rules\BooleansInConditions\BooleanInTernaryOperatorRule
 	- PHPStan\Rules\DisallowedConstructs\DisallowedEmptyRule
+	- PHPStan\Rules\Methods\WrongCaseOfInheritedMethodRule
 	- PHPStan\Rules\StrictCalls\DynamicCallOnStaticMethodsRule
 	- PHPStan\Rules\StrictCalls\StrictFunctionCallsRule
 	- PHPStan\Rules\SwitchConditions\MatchingTypeInSwitchCaseConditionRule
+
+services:
+	scopeIsInClass:
+		class: PHPStan\Build\ScopeIsInClassTypeSpecifyingExtension
+		arguments:
+			isInMethodName: isInClass
+			removeNullMethodName: getClassReflection
+		tags:
+			- phpstan.typeSpecifier.methodTypeSpecifyingExtension
+
+	scopeIsInTrait:
+		class: PHPStan\Build\ScopeIsInClassTypeSpecifyingExtension
+		arguments:
+			isInMethodName: isInTrait
+			removeNullMethodName: getTraitReflection
+		tags:
+			- phpstan.typeSpecifier.methodTypeSpecifyingExtension

src/Rules/Methods/WrongCaseOfInheritedMethodRule.php

@@ -0,0 +1,85 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Methods;
+
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\ClassReflection;
+
+class WrongCaseOfInheritedMethodRule implements \PHPStan\Rules\Rule
+{
+
+	public function getNodeType(): string
+	{
+		return \PhpParser\Node\Stmt\ClassMethod::class;
+	}
+
+	/**
+	 * @param \PhpParser\Node\Stmt\ClassMethod $node
+	 * @param \PHPStan\Analyser\Scope $scope
+	 * @return string[]
+	 */
+	public function processNode(
+		\PhpParser\Node $node,
+		Scope $scope
+	): array
+	{
+		if (!$scope->isInClass()) {
+			throw new \PHPStan\ShouldNotHappenException();
+		}
+
+		$methodReflection = $scope->getClassReflection()->getNativeMethod($node->name);
+		$declaringClass = $methodReflection->getDeclaringClass();
+
+		$messages = [];
+		if ($declaringClass->getParentClass() !== false) {
+			$parentMessage = $this->findMethod(
+				$declaringClass,
+				$declaringClass->getParentClass(),
+				$node->name
+			);
+			if ($parentMessage !== null) {
+				$messages[] = $parentMessage;
+			}
+		}
+
+		foreach ($declaringClass->getInterfaces() as $interface) {
+			$interfaceMessage = $this->findMethod(
+				$declaringClass,
+				$interface,
+				$node->name
+			);
+			if ($interfaceMessage === null) {
+				continue;
+			}
+			$messages[] = $interfaceMessage;
+		}
+
+		return $messages;
+	}
+
+	private function findMethod(
+		ClassReflection $declaringClass,
+		ClassReflection $classReflection,
+		string $methodName
+	): ?string
+	{
+		if (!$classReflection->hasNativeMethod($methodName)) {
+			return null;
+		}
+
+		$parentMethod = $classReflection->getNativeMethod($methodName);
+		if ($parentMethod->getName() === $methodName) {
+			return null;
+		}
+
+		return sprintf(
+			'Method %s::%s() does not match %s method name: %s::%s()',
+			$declaringClass->getName(),
+			$methodName,
+			$classReflection->isInterface() ? 'interface' : 'parent',
+			$classReflection->getName(),
+			$parentMethod->getName()
+		);
+	}
+
+}

tests/Rules/Methods/WrongCaseOfInheritedMethodRuleTest.php

@@ -0,0 +1,27 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Methods;
+
+class WrongCaseOfInheritedMethodRuleTest extends \PHPStan\Testing\RuleTestCase
+{
+
+	protected function getRule(): \PHPStan\Rules\Rule
+	{
+		return new WrongCaseOfInheritedMethodRule();
+	}
+
+	public function testRule(): void
+	{
+		$this->analyse([__DIR__ . '/data/wrong-case.php'], [
+			[
+				'Method WrongCase\Foo::GETfoo() does not match interface method name: WrongCase\FooInterface::getFoo()',
+				25,
+			],
+			[
+				'Method WrongCase\Foo::GETbar() does not match parent method name: WrongCase\FooParent::getBar()',
+				30,
+			],
+		]);
+	}
+
+}

tests/Rules/Methods/data/wrong-case.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace WrongCase;
+
+interface FooInterface
+{
+
+	public function getFoo();
+
+}
+
+class FooParent
+{
+
+	public function getBar()
+	{
+
+	}
+
+}
+
+class Foo extends FooParent implements FooInterface
+{
+
+	public function GETfoo()
+	{
+
+	}
+
+	public function GETbar()
+	{
+
+	}
+
+	public function getBaz()
+	{
+
+	}
+
+}