Bleeding edge - check template type variance in @param-out

Author: ondrejmirtes

conf/bleedingEdge.neon

@@ -31,3 +31,4 @@ parameters:
 		closureDefaultParameterTypeRule: true
 		newRuleLevelHelper: true
 		instanceofType: true
+		paramOutVariance: true

conf/config.neon

@@ -61,6 +61,7 @@ parameters:
 		closureDefaultParameterTypeRule: false
 		newRuleLevelHelper: false
 		instanceofType: false
+		paramOutVariance: false
 	fileExtensions:
 		- php
 	checkAdvancedIsset: false
@@ -289,6 +290,7 @@ parametersSchema:
 		closureDefaultParameterTypeRule: bool()
 		newRuleLevelHelper: bool()
 		instanceofType: bool()
+		paramOutVariance: bool()
 	])
 	fileExtensions: listOf(string())
 	checkAdvancedIsset: bool()
@@ -1031,6 +1033,8 @@ services:
 
 	-
 		class: PHPStan\Rules\Generics\VarianceCheck
+		arguments:
+			checkParamOutVariance: %featureToggles.paramOutVariance%
 
 	-
 		class: PHPStan\Rules\IssetCheck

src/Rules/Generics/FunctionSignatureVarianceRule.php

@@ -33,6 +33,7 @@ public function processNode(Node $node, Scope $scope): array
 		return $this->varianceCheck->checkParametersAcceptor(
 			ParametersAcceptorSelector::selectSingle($functionReflection->getVariants()),
 			sprintf('in parameter %%s of function %s()', SprintfHelper::escapeFormatString($functionName)),
+			sprintf('in param-out type of parameter %%s of function %s()', SprintfHelper::escapeFormatString($functionName)),
 			sprintf('in return type of function %s()', $functionName),
 			sprintf('in function %s()', $functionName),
 			false,

src/Rules/Generics/MethodSignatureVarianceRule.php

@@ -32,6 +32,7 @@ public function processNode(Node $node, Scope $scope): array
 		return $this->varianceCheck->checkParametersAcceptor(
 			ParametersAcceptorSelector::selectSingle($method->getVariants()),
 			sprintf('in parameter %%s of method %s::%s()', SprintfHelper::escapeFormatString($method->getDeclaringClass()->getDisplayName()), SprintfHelper::escapeFormatString($method->getName())),
+			sprintf('in param-out type of parameter %%s of method %s::%s()', SprintfHelper::escapeFormatString($method->getDeclaringClass()->getDisplayName()), SprintfHelper::escapeFormatString($method->getName())),
 			sprintf('in return type of method %s::%s()', $method->getDeclaringClass()->getDisplayName(), $method->getName()),
 			sprintf('in method %s::%s()', $method->getDeclaringClass()->getDisplayName(), $method->getName()),
 			$method->getName() === '__construct' || $method->isStatic(),

src/Rules/Generics/VarianceCheck.php

@@ -13,10 +13,17 @@
 class VarianceCheck
 {
 
+	public function __construct(
+		private bool $checkParamOutVariance,
+	)
+	{
+	}
+
 	/** @return RuleError[] */
 	public function checkParametersAcceptor(
 		ParametersAcceptorWithPhpDocs $parametersAcceptor,
 		string $parameterTypeMessage,
+		string $parameterOutTypeMessage,
 		string $returnTypeMessage,
 		string $generalMessage,
 		bool $isStatic,
@@ -44,20 +51,35 @@ public function checkParametersAcceptor(
 			return $errors;
 		}
 
+		$covariant = TemplateTypeVariance::createCovariant();
+		$parameterVariance = $isStatic
+			? TemplateTypeVariance::createStatic()
+			: TemplateTypeVariance::createContravariant();
+
 		foreach ($parametersAcceptor->getParameters() as $parameterReflection) {
-			$variance = $isStatic
-				? TemplateTypeVariance::createStatic()
-				: TemplateTypeVariance::createContravariant();
 			$type = $parameterReflection->getType();
 			$message = sprintf($parameterTypeMessage, $parameterReflection->getName());
-			foreach ($this->check($variance, $type, $message) as $error) {
+			foreach ($this->check($parameterVariance, $type, $message) as $error) {
+				$errors[] = $error;
+			}
+
+			if (!$this->checkParamOutVariance) {
+				continue;
+			}
+
+			$paramOutType = $parameterReflection->getOutType();
+			if ($paramOutType === null) {
+				continue;
+			}
+
+			$outMessage = sprintf($parameterOutTypeMessage, $parameterReflection->getName());
+			foreach ($this->check($covariant, $paramOutType, $outMessage) as $error) {
 				$errors[] = $error;
 			}
 		}
 
-		$variance = TemplateTypeVariance::createCovariant();
 		$type = $parametersAcceptor->getReturnType();
-		foreach ($this->check($variance, $type, $returnTypeMessage) as $error) {
+		foreach ($this->check($covariant, $type, $returnTypeMessage) as $error) {
 			$errors[] = $error;
 		}
 

tests/PHPStan/Rules/Generics/ClassAncestorsRuleTest.php

@@ -17,7 +17,7 @@ protected function getRule(): Rule
 			new GenericAncestorsCheck(
 				$this->createReflectionProvider(),
 				new GenericObjectTypeCheck(),
-				new VarianceCheck(),
+				new VarianceCheck(true),
 				true,
 				[],
 			),

tests/PHPStan/Rules/Generics/EnumAncestorsRuleTest.php

@@ -18,7 +18,7 @@ protected function getRule(): Rule
 			new GenericAncestorsCheck(
 				$this->createReflectionProvider(),
 				new GenericObjectTypeCheck(),
-				new VarianceCheck(),
+				new VarianceCheck(true),
 				true,
 				[],
 			),

tests/PHPStan/Rules/Generics/InterfaceAncestorsRuleTest.php

@@ -17,7 +17,7 @@ protected function getRule(): Rule
 			new GenericAncestorsCheck(
 				$this->createReflectionProvider(),
 				new GenericObjectTypeCheck(),
-				new VarianceCheck(),
+				new VarianceCheck(true),
 				true,
 				[],
 			),

tests/PHPStan/Rules/Generics/MethodSignatureVarianceRuleTest.php

@@ -173,6 +173,10 @@ public function testRule(): void
 				'Template type X is declared as contravariant, but occurs in invariant position in return type of method MethodSignatureVariance\Contravariant\C::m().',
 				71,
 			],
+			[
+				'Template type X is declared as contravariant, but occurs in covariant position in param-out type of parameter a of method MethodSignatureVariance\Contravariant\C::paramOut().',
+				79,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/Generics/UsedTraitsRuleTest.php

@@ -19,7 +19,7 @@ protected function getRule(): Rule
 			new GenericAncestorsCheck(
 				$this->createReflectionProvider(),
 				new GenericObjectTypeCheck(),
-				new VarianceCheck(),
+				new VarianceCheck(true),
 				true,
 				[],
 			),

tests/PHPStan/Rules/Generics/data/method-signature-variance-contravariant.php

@@ -72,4 +72,12 @@ function m() {}
 
 	/** @return X */
 	private function n() {}
+
+	/**
+	 * @param-out X $a
+	 */
+	public function paramOut(&$a)
+	{
+
+	}
 }