Support ::class on expression (PHP 8.0)

https://wiki.php.net/rfc/class_name_literal_on_object
phpstan · Oct 16, 2020 · cec1be7 · cec1be7
1 parent 869f27b
commit cec1be7
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Showing 7 changed files with 169 additions and 6 deletions.
diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
@@ -1586,15 +1586,26 @@ private function resolveType(Expr $node): Type
 					}
 					$constantClassType = new ObjectType($resolvedName);
 				}
+
+				if (strtolower($constantName) === 'class') {
+					return new ConstantStringType($constantClassType->getClassName(), true);
+				}
 			} else {
 				$constantClassType = $this->getType($node->class);
 			}
 
-			if (strtolower($constantName) === 'class' && $constantClassType instanceof TypeWithClassName) {
-				return new ConstantStringType($constantClassType->getClassName(), true);
-			}
-
 			$referencedClasses = TypeUtils::getDirectClassNames($constantClassType);
+			if (strtolower($constantName) === 'class') {
+				if (count($referencedClasses) === 0) {
+					return new ErrorType();
+				}
+				$classTypes = [];
+				foreach ($referencedClasses as $referencedClass) {
+					$classTypes[] = new GenericClassStringType(new ObjectType($referencedClass));
+				}
+
+				return TypeCombinator::union(...$classTypes);
+			}
 			$types = [];
 			foreach ($referencedClasses as $referencedClass) {
 				if (!$this->reflectionProvider->hasClass($referencedClass)) {

diff --git a/src/Php/PhpVersion.php b/src/Php/PhpVersion.php
@@ -66,4 +66,9 @@ public function supportsThrowExpression(): bool
 		return $this->versionId >= 80000;
 	}
 
+	public function supportsClassConstantOnExpression(): bool
+	{
+		return $this->versionId >= 80000;
+	}
+
 }
diff --git a/src/Rules/Classes/ClassConstantRule.php b/src/Rules/Classes/ClassConstantRule.php
@@ -5,6 +5,7 @@
 use PhpParser\Node;
 use PhpParser\Node\Expr\ClassConstFetch;
 use PHPStan\Analyser\Scope;
+use PHPStan\Php\PhpVersion;
 use PHPStan\Reflection\ReflectionProvider;
 use PHPStan\Rules\ClassCaseSensitivityCheck;
 use PHPStan\Rules\ClassNameNodePair;
@@ -30,15 +31,19 @@ class ClassConstantRule implements \PHPStan\Rules\Rule
 
 	private \PHPStan\Rules\ClassCaseSensitivityCheck $classCaseSensitivityCheck;
 
+	private PhpVersion $phpVersion;
+
 	public function __construct(
 		ReflectionProvider $reflectionProvider,
 		RuleLevelHelper $ruleLevelHelper,
-		ClassCaseSensitivityCheck $classCaseSensitivityCheck
+		ClassCaseSensitivityCheck $classCaseSensitivityCheck,
+		PhpVersion $phpVersion
 	)
 	{
 		$this->reflectionProvider = $reflectionProvider;
 		$this->ruleLevelHelper = $ruleLevelHelper;
 		$this->classCaseSensitivityCheck = $classCaseSensitivityCheck;
+		$this->phpVersion = $phpVersion;
 	}
 
 	public function getNodeType(): string
@@ -107,6 +112,10 @@ public function processNode(Node $node, Scope $scope): array
 				$className = $this->reflectionProvider->getClass($className)->getName();
 			}
 
+			if (strtolower($constantName) === 'class') {
+				return $messages;
+			}
+
 			if ($scope->isInClass() && $scope->getClassReflection()->getName() === $className) {
 				$classType = new ThisType($scope->getClassReflection());
 			} else {
@@ -125,6 +134,24 @@ static function (Type $type) use ($constantName): bool {
 			if ($classType instanceof ErrorType) {
 				return $classTypeResult->getUnknownClassErrors();
 			}
+
+			if (strtolower($constantName) === 'class') {
+				if (!$this->phpVersion->supportsClassConstantOnExpression()) {
+					return [
+						RuleErrorBuilder::message('Accessing ::class constant on an expression is supported only on PHP 8.0 and later.')
+							->nonIgnorable()
+							->build(),
+					];
+				}
+
+				if ((new StringType())->isSuperTypeOf($classType)->yes()) {
+					return [
+						RuleErrorBuilder::message('Accessing ::class constant on a dynamic string is not supported in PHP.')
+							->nonIgnorable()
+							->build(),
+					];
+				}
+			}
 		}
 
 		if ((new StringType())->isSuperTypeOf($classType)->yes()) {

diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -10176,6 +10176,15 @@ public function dataNotEmptyArray(): array
 		return $this->gatherAssertTypes(__DIR__ . '/data/non-empty-array.php');
 	}
 
+	public function dataClassConstantOnExpression(): array
+	{
+		if (PHP_VERSION_ID < 80000 && !self::$useStaticReflectionProvider) {
+			return [];
+		}
+
+		return $this->gatherAssertTypes(__DIR__ . '/data/class-constant-on-expr.php');
+	}
+
 	/**
 	 * @dataProvider dataBug2574
 	 * @dataProvider dataBug2577
@@ -10255,6 +10264,7 @@ public function dataNotEmptyArray(): array
 	 * @dataProvider dataPow
 	 * @dataProvider dataThrowExpression
 	 * @dataProvider dataNotEmptyArray
+	 * @dataProvider dataClassConstantOnExpression
 	 * @param string $assertType
 	 * @param string $file
 	 * @param mixed ...$args

diff --git a/tests/PHPStan/Analyser/data/class-constant-on-expr.php b/tests/PHPStan/Analyser/data/class-constant-on-expr.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace ClassConstantOnExprAssertType;
+
+use function PHPStan\Analyser\assertType;
+
+class Foo
+{
+
+	public function doFoo(
+		\stdClass $std,
+		string $string,
+		?\stdClass $stdOrNull,
+		?string $stringOrNull
+	): void
+	{
+		assertType('class-string<stdClass>', $std::class);
+		assertType('*ERROR*', $string::class);
+		assertType('class-string<stdClass>', $stdOrNull::class);
+		assertType('*ERROR*', $stringOrNull::class);
+	}
+
+}
diff --git a/tests/PHPStan/Rules/Classes/ClassConstantRuleTest.php b/tests/PHPStan/Rules/Classes/ClassConstantRuleTest.php
@@ -2,6 +2,7 @@
 
 namespace PHPStan\Rules\Classes;
 
+use PHPStan\Php\PhpVersion;
 use PHPStan\Rules\ClassCaseSensitivityCheck;
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleLevelHelper;
@@ -12,14 +13,18 @@
 class ClassConstantRuleTest extends \PHPStan\Testing\RuleTestCase
 {
 
+	/** @var int */
+	private $phpVersion;
+
 	protected function getRule(): Rule
 	{
 		$broker = $this->createReflectionProvider();
-		return new ClassConstantRule($broker, new RuleLevelHelper($broker, true, false, true, false), new ClassCaseSensitivityCheck($broker));
+		return new ClassConstantRule($broker, new RuleLevelHelper($broker, true, false, true, false), new ClassCaseSensitivityCheck($broker), new PhpVersion($this->phpVersion));
 	}
 
 	public function testClassConstant(): void
 	{
+		$this->phpVersion = PHP_VERSION_ID;
 		$this->analyse(
 			[
 				__DIR__ . '/data/class-constant.php',
@@ -85,6 +90,8 @@ public function testClassConstantVisibility(): void
 		if (!self::$useStaticReflectionProvider && PHP_VERSION_ID >= 70400) {
 			$this->markTestSkipped('Test does not run on PHP 7.4 because of referencing parent:: without parent class.');
 		}
+
+		$this->phpVersion = PHP_VERSION_ID;
 		$this->analyse([__DIR__ . '/data/class-constant-visibility.php'], [
 			[
 				'Access to private constant PRIVATE_BAR of class ClassConstantVisibility\Bar.',
@@ -149,6 +156,7 @@ public function testClassConstantVisibility(): void
 
 	public function testClassExists(): void
 	{
+		$this->phpVersion = PHP_VERSION_ID;
 		$this->analyse([__DIR__ . '/data/class-exists.php'], [
 			[
 				'Class UnknownClass\Bar not found.',
@@ -168,4 +176,62 @@ public function testClassExists(): void
 		]);
 	}
 
+	public function dataClassConstantOnExpression(): array
+	{
+		return [
+			[
+				70400,
+				[
+					[
+						'Accessing ::class constant on an expression is supported only on PHP 8.0 and later.',
+						15,
+					],
+					[
+						'Accessing ::class constant on an expression is supported only on PHP 8.0 and later.',
+						16,
+					],
+					[
+						'Accessing ::class constant on an expression is supported only on PHP 8.0 and later.',
+						17,
+					],
+					[
+						'Accessing ::class constant on an expression is supported only on PHP 8.0 and later.',
+						18,
+					],
+				],
+			],
+			[
+				80000,
+				[
+					[
+						'Accessing ::class constant on a dynamic string is not supported in PHP.',
+						16,
+					],
+					[
+						'Cannot access constant class on stdClass|null.',
+						17,
+					],
+					[
+						'Cannot access constant class on string|null.',
+						18,
+					],
+				],
+			],
+		];
+	}
+
+	/**
+	 * @dataProvider dataClassConstantOnExpression
+	 * @param int $phpVersion
+	 * @param mixed[] $errors
+	 */
+	public function testClassConstantOnExpression(int $phpVersion, array $errors): void
+	{
+		if (!self::$useStaticReflectionProvider) {
+			$this->markTestSkipped('Test requires static reflection');
+		}
+		$this->phpVersion = $phpVersion;
+		$this->analyse([__DIR__ . '/data/class-constant-on-expr.php'], $errors);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Classes/data/class-constant-on-expr.php b/tests/PHPStan/Rules/Classes/data/class-constant-on-expr.php
@@ -0,0 +1,21 @@
+<?php // lint >= 8.0
+
+namespace ClassConstantOnExpr;
+
+class Foo
+{
+
+	public function doFoo(
+		\stdClass $std,
+		string $string,
+		?\stdClass $stdOrNull,
+		?string $stringOrNull
+	): void
+	{
+		echo $std::class;
+		echo $string::class;
+		echo $stdOrNull::class;
+		echo $stringOrNull::class;
+	}
+
+}