Add stringable access check to ClassConstantRule

conf/bleedingEdge.neon

@@ -1,6 +1,7 @@
 parameters:
 	featureToggles:
 		bleedingEdge: true
+		checkNonStringableDynamicAccess: true
 		checkParameterCastableToNumberFunctions: true
 		skipCheckGenericClasses!: []
 		stricterFunctionMap: true

conf/config.neon

@@ -24,6 +24,7 @@ parameters:
 			tooWideThrowType: true
 	featureToggles:
 		bleedingEdge: false
+		checkNonStringableDynamicAccess: false
 		checkParameterCastableToNumberFunctions: false
 		skipCheckGenericClasses: []
 		stricterFunctionMap: false

conf/parametersSchema.neon

@@ -28,6 +28,7 @@ parametersSchema:
 	])
 	featureToggles: structure([
 		bleedingEdge: bool(),
+		checkNonStringableDynamicAccess: bool(),
 		checkParameterCastableToNumberFunctions: bool(),
 		skipCheckGenericClasses: listOf(string()),
 		stricterFunctionMap: bool()

src/Rules/Classes/ClassConstantRule.php

@@ -5,9 +5,11 @@
 use PhpParser\Node;
 use PhpParser\Node\Expr\BinaryOp\Identical;
 use PhpParser\Node\Expr\ClassConstFetch;
+use PhpParser\Node\Name;
 use PhpParser\Node\Scalar\String_;
 use PHPStan\Analyser\NullsafeOperatorHelper;
 use PHPStan\Analyser\Scope;
+use PHPStan\DependencyInjection\AutowiredParameter;
 use PHPStan\DependencyInjection\RegisteredRule;
 use PHPStan\Internal\SprintfHelper;
 use PHPStan\Php\PhpVersion;
@@ -42,6 +44,8 @@ public function __construct(
 		private RuleLevelHelper $ruleLevelHelper,
 		private ClassNameCheck $classCheck,
 		private PhpVersion $phpVersion,
+		#[AutowiredParameter(ref: '%featureToggles.checkNonStringableDynamicAccess%')]
+		private bool $checkNonStringableDynamicAccess,
 	)
 	{
 	}
@@ -63,6 +67,27 @@ public function processNode(Node $node, Scope $scope): array
 				$name = $constantString->getValue();
 				$constantNameScopes[$name] = $scope->filterByTruthyValue(new Identical($node->name, new String_($name)));
 			}
+
+			if ($this->checkNonStringableDynamicAccess) {
+				$nameTypeResult = $this->ruleLevelHelper->findTypeToCheck(
+					$scope,
+					$node->name,
+					'',
+					static fn (Type $type) => $type->isString()->yes(),
+				);
+
+				$type = $nameTypeResult->getType();
+
+				if (!$type->isString()->yes()) {
+					$className = $node->class instanceof Name
+						? $scope->resolveName($node->class)
+						: $scope->getType($node->class)->describe(VerbosityLevel::typeOnly());
+
+					$errors[] = RuleErrorBuilder::message(sprintf('Class constant name for %s must be a string, but %s was given.', $className, $nameType->describe(VerbosityLevel::precise())))
+						->identifier('classConstant.nameNotString')
+						->build();
+				}
+			}
 		}
 
 		foreach ($constantNameScopes as $constantName => $constantScope) {

tests/PHPStan/Rules/Classes/ClassConstantRuleTest.php

@@ -26,14 +26,15 @@ protected function getRule(): Rule
 		$reflectionProvider = self::createReflectionProvider();
 		return new ClassConstantRule(
 			$reflectionProvider,
-			new RuleLevelHelper($reflectionProvider, true, false, true, false, false, false, true),
+			new RuleLevelHelper($reflectionProvider, true, false, true, true, true, false, true),
 			new ClassNameCheck(
 				new ClassCaseSensitivityCheck($reflectionProvider, true),
 				new ClassForbiddenNameCheck(self::getContainer()),
 				$reflectionProvider,
 				self::getContainer(),
 			),
 			new PhpVersion($this->phpVersion),
+			true,
 		);
 	}
 
@@ -59,6 +60,10 @@ public function testClassConstant(): void
 					'Access to undefined constant ClassConstantNamespace\Foo::DOLOR.',
 					10,
 				],
+				[
+					'Cannot access constant LOREM on mixed.',
+					11,
+				],
 				[
 					'Access to undefined constant ClassConstantNamespace\Foo::DOLOR.',
 					16,
@@ -439,6 +444,14 @@ public function testDynamicAccess(): void
 		$this->phpVersion = PHP_VERSION_ID;
 
 		$this->analyse([__DIR__ . '/data/dynamic-constant-access.php'], [
+			[
+				'Access to undefined constant ClassConstantDynamicAccess\Foo::FOO.',
+				17,
+			],
+			[
+				'Class constant name for ClassConstantDynamicAccess\Foo must be a string, but object was given.',
+				19,
+			],
 			[
 				'Access to undefined constant ClassConstantDynamicAccess\Foo::FOO.',
 				20,
@@ -474,4 +487,61 @@ public function testDynamicAccess(): void
 		]);
 	}
 
+	#[RequiresPhp('>= 8.3')]
+	public function testStringableDynamicAccess(): void
+	{
+		$this->phpVersion = PHP_VERSION_ID;
+
+		$this->analyse([__DIR__ . '/data/dynamic-constant-stringable-access.php'], [
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Foo must be a string, but mixed was given.',
+				14,
+			],
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Foo must be a string, but string|null was given.',
+				15,
+			],
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Foo must be a string, but Stringable|null was given.',
+				16,
+			],
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Foo must be a string, but int was given.',
+				17,
+			],
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Foo must be a string, but int|null was given.',
+				18,
+			],
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Foo must be a string, but DateTime|string was given.',
+				19,
+			],
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Foo must be a string, but 1111 was given.',
+				20,
+			],
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Foo must be a string, but Stringable was given.',
+				22,
+			],
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Foo must be a string, but mixed was given.',
+				32,
+			],
+			[
+				'Class constant name for ClassConstantDynamicStringableAccess\Bar must be a string, but mixed was given.',
+				33,
+			],
+			[
+				'Class constant name for DateTime|DateTimeImmutable must be a string, but mixed was given.',
+				38,
+			],
+			[
+				'Class constant name for object must be a string, but mixed was given.',
+				39,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Classes/data/dynamic-constant-access.php

@@ -14,7 +14,7 @@ public function test(string $string, object $obj): void
 	{
 		$bar = 'FOO';
 
-		echo self::{$foo};
+		echo self::{$bar};
 		echo self::{$string};
 		echo self::{$obj};
 		echo self::{$this->name};
@@ -44,5 +44,4 @@ public function testScope(): void
 		echo self::{$name};
 	}
 
-
 }

tests/PHPStan/Rules/Classes/data/dynamic-constant-stringable-access.php

@@ -0,0 +1,42 @@
+<?php  // lint >= 8.3
+
+namespace ClassConstantDynamicStringableAccess;
+
+use Stringable;
+use DateTime;
+use DateTimeImmutable;
+
+abstract class Foo
+{
+
+	public function test(mixed $mixed, ?string $nullableStr, ?Stringable $nullableStringable, int $int, ?int $nullableInt, DateTime|string $datetimeOrStr, Stringable $stringable): void
+	{
+		echo self::{$mixed};
+		echo self::{$nullableStr};
+		echo self::{$nullableStringable};
+		echo self::{$int};
+		echo self::{$nullableInt};
+		echo self::{$datetimeOrStr};
+		echo self::{1111};
+		echo self::{(string)$stringable};
+		echo self::{$stringable}; // Uncast Stringable objects will cause a runtime error
+	}
+
+}
+
+final class Bar extends Foo
+{
+
+	public function test(mixed $mixed, ?string $nullableStr, ?Stringable $nullableStringable, int $int, ?int $nullableInt, DateTime|string $datetimeOrStr, Stringable $stringable): void
+	{
+		echo parent::{$mixed};
+		echo self::{$mixed};
+	}
+
+	public function testClassDynamic(DateTime|DateTimeImmutable $datetime, object $obj, mixed $mixed): void
+	{
+		echo $datetime::{$mixed};
+		echo $obj::{$mixed};
+	}
+
+}