From f6eebc6be877d6b945234705622e99df876d860b Mon Sep 17 00:00:00 2001
From: "John Paul E. Balandan, CPA" <paulbalandan@gmail.com>
Date: Sun, 1 Dec 2024 02:45:14 +0800
Subject: [PATCH] Introduce `ClassAsClassConstantRule`

---
 Makefile                                      |  1 +
 conf/config.level0.neon                       |  1 +
 .../Constants/ClassAsClassConstantRule.php    | 40 +++++++++++++++++++
 .../ClassAsClassConstantRuleTest.php          | 33 +++++++++++++++
 .../data/class-as-class-constant.php          | 17 ++++++++
 5 files changed, 92 insertions(+)
 create mode 100644 src/Rules/Constants/ClassAsClassConstantRule.php
 create mode 100644 tests/PHPStan/Rules/Constants/ClassAsClassConstantRuleTest.php
 create mode 100644 tests/PHPStan/Rules/Constants/data/class-as-class-constant.php

diff --git a/Makefile b/Makefile
index 3282ee2c4e..11807088ca 100644
--- a/Makefile
+++ b/Makefile
@@ -54,6 +54,7 @@ lint:
 		--exclude tests/PHPStan/Rules/Classes/data/first-class-instantiation-callable.php \
 		--exclude tests/PHPStan/Rules/Classes/data/instantiation-callable.php \
 		--exclude tests/PHPStan/Rules/Classes/data/bug-9402.php \
+		--exclude tests/PHPStan/Rules/Constants/data/class-as-class-constant.php \
 		--exclude tests/PHPStan/Rules/Constants/data/value-assigned-to-class-constant-native-type.php \
 		--exclude tests/PHPStan/Rules/Constants/data/overriding-constant-native-types.php \
 		--exclude tests/PHPStan/Rules/Methods/data/bug-10043.php \
diff --git a/conf/config.level0.neon b/conf/config.level0.neon
index 1382d99ee1..15f1048b86 100644
--- a/conf/config.level0.neon
+++ b/conf/config.level0.neon
@@ -68,6 +68,7 @@ rules:
 	- PHPStan\Rules\Classes\NonClassAttributeClassRule
 	- PHPStan\Rules\Classes\ReadOnlyClassRule
 	- PHPStan\Rules\Classes\TraitAttributeClassRule
+	- PHPStan\Rules\Constants\ClassAsClassConstantRule
 	- PHPStan\Rules\Constants\DynamicClassConstantFetchRule
 	- PHPStan\Rules\Constants\FinalConstantRule
 	- PHPStan\Rules\Constants\NativeTypedClassConstantRule
diff --git a/src/Rules/Constants/ClassAsClassConstantRule.php b/src/Rules/Constants/ClassAsClassConstantRule.php
new file mode 100644
index 0000000000..b10d2d0080
--- /dev/null
+++ b/src/Rules/Constants/ClassAsClassConstantRule.php
@@ -0,0 +1,40 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Constants;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+
+/**
+ * @implements Rule<Node\Stmt\ClassConst>
+ */
+final class ClassAsClassConstantRule implements Rule
+{
+
+	public function getNodeType(): string
+	{
+		return Node\Stmt\ClassConst::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		$errors = [];
+
+		foreach ($node->consts as $const) {
+			if ($const->name->toLowerString() !== 'class') {
+				continue;
+			}
+
+			$errors[] = RuleErrorBuilder::message('A class constant must not be called \'class\'; it is reserved for class name fetching.')
+				->line($const->getStartLine())
+				->identifier('classConstant.class')
+				->nonIgnorable()
+				->build();
+		}
+
+		return $errors;
+	}
+
+}
diff --git a/tests/PHPStan/Rules/Constants/ClassAsClassConstantRuleTest.php b/tests/PHPStan/Rules/Constants/ClassAsClassConstantRuleTest.php
new file mode 100644
index 0000000000..1a8fda4bf6
--- /dev/null
+++ b/tests/PHPStan/Rules/Constants/ClassAsClassConstantRuleTest.php
@@ -0,0 +1,33 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Constants;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<ClassAsClassConstantRule>
+ */
+class ClassAsClassConstantRuleTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new ClassAsClassConstantRule();
+	}
+
+	public function testRule(): void
+	{
+		$this->analyse([__DIR__ . '/data/class-as-class-constant.php'], [
+			[
+				'A class constant must not be called \'class\'; it is reserved for class name fetching.',
+				9,
+			],
+			[
+				'A class constant must not be called \'class\'; it is reserved for class name fetching.',
+				16,
+			],
+		]);
+	}
+
+}
diff --git a/tests/PHPStan/Rules/Constants/data/class-as-class-constant.php b/tests/PHPStan/Rules/Constants/data/class-as-class-constant.php
new file mode 100644
index 0000000000..fdf86f77f1
--- /dev/null
+++ b/tests/PHPStan/Rules/Constants/data/class-as-class-constant.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace ClassAsClassConstant;
+
+final class A
+{
+	public const FOO = 'foo';
+	public const BAR = 'bar';
+	public const CLASS = 'qux';
+}
+
+final class B
+{
+	public const YES = 1,
+		NO = 0,
+		CLASS = -1;
+}