Introduce ClosureType::isStaticClosure()

src/Analyser/ExprHandler/Helper/ClosureTypeResolver.php

@@ -220,13 +220,15 @@ static function (Node $node, Scope $scope) use ($arrowScope, &$arrowFunctionImpu
 					usedVariables: $cachedClosureData['usedVariables'],
 					acceptsNamedArguments: TrinaryLogic::createYes(),
 					mustUseReturnValue: $mustUseReturnValue,
+					isStatic: TrinaryLogic::createFromBoolean($expr->static),
 				);
 			}
 			if (self::$resolveClosureTypeDepth >= 2) {
 				return new ClosureType(
 					$parameters,
 					$scope->getFunctionType($expr->returnType, false, false),
 					$isVariadic,
+					isStatic: TrinaryLogic::createFromBoolean($expr->static),
 				);
 			}
 
@@ -446,6 +448,7 @@ static function (Node $node, Scope $scope) use ($arrowScope, &$arrowFunctionImpu
 			usedVariables: $usedVariables,
 			acceptsNamedArguments: TrinaryLogic::createYes(),
 			mustUseReturnValue: $mustUseReturnValue,
+			isStatic: TrinaryLogic::createFromBoolean($expr->static),
 		);
 	}
 

src/PhpDoc/TypeNodeResolver.php

@@ -1041,7 +1041,7 @@ function (CallableTypeParameterNode $parameterNode) use ($nameScope, &$isVariadi
 				),
 			]);
 		} elseif ($mainType instanceof ClosureType) {
-			$closure = new ClosureType($parameters, $returnType, $isVariadic, $templateTypeMap, templateTags: $templateTags, impurePoints: $mainType->getImpurePoints(), invalidateExpressions: $mainType->getInvalidateExpressions(), usedVariables: $mainType->getUsedVariables(), acceptsNamedArguments: $mainType->acceptsNamedArguments(), mustUseReturnValue: $mainType->mustUseReturnValue());
+			$closure = new ClosureType($parameters, $returnType, $isVariadic, $templateTypeMap, templateTags: $templateTags, impurePoints: $mainType->getImpurePoints(), invalidateExpressions: $mainType->getInvalidateExpressions(), usedVariables: $mainType->getUsedVariables(), acceptsNamedArguments: $mainType->acceptsNamedArguments(), mustUseReturnValue: $mainType->mustUseReturnValue(), isStatic: $mainType->isStaticClosure());
 			if ($closure->isPure()->yes() && $returnType->isVoid()->yes()) {
 				return new ErrorType();
 			}

src/Reflection/Callables/CallableParametersAcceptor.php

@@ -60,4 +60,6 @@ public function mustUseReturnValue(): TrinaryLogic;
 
 	public function getAsserts(): Assertions;
 
+	public function isStaticClosure(): TrinaryLogic;
+
 }

src/Reflection/Callables/FunctionCallableVariant.php

@@ -179,4 +179,9 @@ public function getAsserts(): Assertions
 		return $this->function->getAsserts();
 	}
 
+	public function isStaticClosure(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 }

src/Reflection/ExtendedCallableFunctionVariant.php

@@ -38,6 +38,7 @@ public function __construct(
 		private TrinaryLogic $acceptsNamedArguments,
 		private TrinaryLogic $mustUseReturnValue,
 		private ?Assertions $assertions = null,
+		private ?TrinaryLogic $isStatic = null,
 	)
 	{
 		parent::__construct(
@@ -92,4 +93,9 @@ public function getAsserts(): Assertions
 		return $this->assertions ?? Assertions::createEmpty();
 	}
 
+	public function isStaticClosure(): TrinaryLogic
+	{
+		return $this->isStatic ?? TrinaryLogic::createMaybe();
+	}
+
 }

src/Reflection/GenericParametersAcceptorResolver.php

@@ -134,6 +134,7 @@ public static function resolve(array $argTypes, ParametersAcceptor $parametersAc
 				$originalParametersAcceptor->acceptsNamedArguments(),
 				$originalParametersAcceptor->mustUseReturnValue(),
 				$originalParametersAcceptor->getAsserts(),
+				$originalParametersAcceptor->isStaticClosure(),
 			);
 		}
 

src/Reflection/InaccessibleMethod.php

@@ -98,4 +98,9 @@ public function getAsserts(): Assertions
 		return Assertions::createEmpty();
 	}
 
+	public function isStaticClosure(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 }

src/Reflection/InitializerExprTypeResolver.php

@@ -263,6 +263,7 @@ public function getType(Expr $expr, InitializerExprContext $context): Type
 				TemplateTypeMap::createEmpty(),
 				TemplateTypeVarianceMap::createEmpty(),
 				acceptsNamedArguments: TrinaryLogic::createYes(),
+				isStatic: TrinaryLogic::createYes(),
 			);
 		}
 		if ($expr instanceof Expr\ArrayDimFetch && $expr->dim !== null) {

src/Reflection/ParametersAcceptorSelector.php

@@ -736,6 +736,7 @@ public static function combineAcceptors(array $acceptors): ExtendedParametersAcc
 		$usedVariables = [];
 		$acceptsNamedArguments = TrinaryLogic::createNo();
 		$mustUseReturnValue = TrinaryLogic::createMaybe();
+		$isStaticClosure = TrinaryLogic::createMaybe();
 
 		foreach ($acceptors as $acceptor) {
 			$returnTypes[] = $acceptor->getReturnType();
@@ -753,6 +754,7 @@ public static function combineAcceptors(array $acceptors): ExtendedParametersAcc
 				$usedVariables = array_merge($usedVariables, $acceptor->getUsedVariables());
 				$acceptsNamedArguments = $acceptsNamedArguments->or($acceptor->acceptsNamedArguments());
 				$mustUseReturnValue = $mustUseReturnValue->or($acceptor->mustUseReturnValue());
+				$isStaticClosure = $isStaticClosure->or($acceptor->isStaticClosure());
 			}
 			$isVariadic = $isVariadic || $acceptor->isVariadic();
 
@@ -860,6 +862,7 @@ public static function combineAcceptors(array $acceptors): ExtendedParametersAcc
 				$usedVariables,
 				$acceptsNamedArguments,
 				$mustUseReturnValue,
+				isStatic: $isStaticClosure,
 			);
 		}
 
@@ -898,6 +901,7 @@ private static function wrapAcceptor(ParametersAcceptor $acceptor): ExtendedPara
 				$acceptor->acceptsNamedArguments(),
 				$acceptor->mustUseReturnValue(),
 				$acceptor->getAsserts(),
+				$acceptor->isStaticClosure(),
 			);
 		}
 

src/Reflection/ResolvedFunctionVariantWithCallable.php

@@ -30,6 +30,7 @@ public function __construct(
 		private TrinaryLogic $acceptsNamedArguments,
 		private TrinaryLogic $mustUseReturnValue,
 		private ?Assertions $assertions = null,
+		private ?TrinaryLogic $isStatic = null,
 	)
 	{
 	}
@@ -124,4 +125,9 @@ public function getAsserts(): Assertions
 		return $this->assertions ?? Assertions::createEmpty();
 	}
 
+	public function isStaticClosure(): TrinaryLogic
+	{
+		return $this->isStatic ?? TrinaryLogic::createMaybe();
+	}
+
 }

src/Reflection/TrivialParametersAcceptor.php

@@ -108,4 +108,9 @@ public function getAsserts(): Assertions
 		return Assertions::createEmpty();
 	}
 
+	public function isStaticClosure(): TrinaryLogic
+	{
+		return TrinaryLogic::createMaybe();
+	}
+
 }

src/Rules/RuleLevelHelper.php

@@ -123,6 +123,7 @@ private function transformAcceptedType(Type $acceptingType, Type $acceptedType):
 					$acceptedType->getUsedVariables(),
 					$acceptedType->acceptsNamedArguments(),
 					$acceptedType->mustUseReturnValue(),
+					isStatic: $acceptedType->isStaticClosure(),
 				);
 			}
 

src/Type/CallableType.php

@@ -404,6 +404,11 @@ public function getAsserts(): Assertions
 		return Assertions::createEmpty();
 	}
 
+	public function isStaticClosure(): TrinaryLogic
+	{
+		return TrinaryLogic::createMaybe();
+	}
+
 	public function toNumber(): Type
 	{
 		return new ErrorType();

src/Type/CallableTypeHelper.php

@@ -113,6 +113,13 @@ public static function isParametersAcceptorSuperTypeOf(
 			$result = $result->and(new IsSuperTypeOfResult($theirs->isPure()->negate(), []));
 		}
 
+		$ourStatic = $ours->isStaticClosure();
+		if ($ourStatic->yes()) {
+			$result = $result->and(new IsSuperTypeOfResult($theirs->isStaticClosure(), []));
+		} elseif ($ourStatic->no()) {
+			$result = $result->and(new IsSuperTypeOfResult($theirs->isStaticClosure()->negate(), []));
+		}
+
 		return $result->and($isReturnTypeSuperType);
 	}
 

src/Type/ClosureType.php

@@ -88,6 +88,8 @@ class ClosureType implements TypeWithClassName, CallableParametersAcceptor
 
 	private Assertions $assertions;
 
+	private TrinaryLogic $isStatic;
+
 	/**
 	 * @api
 	 * @param list<ParameterReflection>|null $parameters
@@ -112,6 +114,7 @@ public function __construct(
 		?TrinaryLogic $acceptsNamedArguments = null,
 		?TrinaryLogic $mustUseReturnValue = null,
 		?Assertions $assertions = null,
+		?TrinaryLogic $isStatic = null,
 	)
 	{
 		if ($acceptsNamedArguments === null) {
@@ -132,6 +135,7 @@ public function __construct(
 		$this->callSiteVarianceMap = $callSiteVarianceMap ?? TemplateTypeVarianceMap::createEmpty();
 		$this->impurePoints = $impurePoints ?? [new SimpleImpurePoint('functionCall', 'call to an unknown Closure', false)];
 		$this->assertions = $assertions ?? Assertions::createEmpty();
+		$this->isStatic = $isStatic ?? TrinaryLogic::createMaybe();
 	}
 
 	public function getAsserts(): Assertions
@@ -268,7 +272,8 @@ public function equals(Type $type): bool
 		}
 
 		return $this->describe(VerbosityLevel::precise()) === $type->describe(VerbosityLevel::precise())
-			&& $this->isPure()->equals($type->isPure());
+			&& $this->isPure()->equals($type->isPure())
+			&& $this->isStatic->equals($type->isStatic);
 	}
 
 	public function describe(VerbosityLevel $level): string
@@ -306,6 +311,72 @@ function (): string {
 
 				return $printer->print($selfWithoutParameterNames->toPhpDocNode());
 			},
+			function (): string {
+				$prefix = $this->isStatic->yes() ? 'static ' : '';
+				if ($this->isCommonCallable) {
+					$name = $this->isPure()->yes() ? 'pure-Closure' : 'Closure';
+					return $prefix . $name;
+				}
+
+				$printer = new Printer();
+				$selfWithoutParameterNames = new self(
+					array_map(static fn (ParameterReflection $p): ParameterReflection => new DummyParameter(
+						'',
+						$p->getType(),
+						optional: $p->isOptional() && !$p->isVariadic(),
+						passedByReference: PassedByReference::createNo(),
+						variadic: $p->isVariadic(),
+						defaultValue: $p->getDefaultValue(),
+					), $this->parameters),
+					$this->returnType,
+					$this->variadic,
+					$this->templateTypeMap,
+					$this->resolvedTemplateTypeMap,
+					$this->callSiteVarianceMap,
+					$this->templateTags,
+					$this->throwPoints,
+					$this->impurePoints,
+					$this->invalidateExpressions,
+					$this->usedVariables,
+					$this->acceptsNamedArguments,
+					$this->mustUseReturnValue,
+				);
+
+				return $prefix . $printer->print($selfWithoutParameterNames->toPhpDocNode());
+			},
+			function (): string {
+				$prefix = !$this->isStatic->maybe() ? ($this->isStatic->yes() ? 'static ' : 'non-static ') : '';
+				if ($this->isCommonCallable) {
+					$name = $this->isPure()->yes() ? 'pure-Closure' : 'Closure';
+					return $prefix . $name;
+				}
+
+				$printer = new Printer();
+				$selfWithoutParameterNames = new self(
+					array_map(static fn (ParameterReflection $p): ParameterReflection => new DummyParameter(
+						'',
+						$p->getType(),
+						optional: $p->isOptional() && !$p->isVariadic(),
+						passedByReference: PassedByReference::createNo(),
+						variadic: $p->isVariadic(),
+						defaultValue: $p->getDefaultValue(),
+					), $this->parameters),
+					$this->returnType,
+					$this->variadic,
+					$this->templateTypeMap,
+					$this->resolvedTemplateTypeMap,
+					$this->callSiteVarianceMap,
+					$this->templateTags,
+					$this->throwPoints,
+					$this->impurePoints,
+					$this->invalidateExpressions,
+					$this->usedVariables,
+					$this->acceptsNamedArguments,
+					$this->mustUseReturnValue,
+				);
+
+				return $prefix . $printer->print($selfWithoutParameterNames->toPhpDocNode());
+			},
 		);
 	}
 
@@ -496,6 +567,11 @@ public function mustUseReturnValue(): TrinaryLogic
 		return $this->mustUseReturnValue;
 	}
 
+	public function isStaticClosure(): TrinaryLogic
+	{
+		return $this->isStatic;
+	}
+
 	public function isCloneable(): TrinaryLogic
 	{
 		return TrinaryLogic::createYes();
@@ -709,6 +785,7 @@ public function traverse(callable $cb): Type
 			$this->acceptsNamedArguments,
 			$this->mustUseReturnValue,
 			$this->assertions,
+			$this->isStatic,
 		);
 	}
 
@@ -761,6 +838,7 @@ public function traverseSimultaneously(Type $right, callable $cb): Type
 			$this->acceptsNamedArguments,
 			$this->mustUseReturnValue,
 			$this->assertions,
+			$this->isStatic,
 		);
 	}
 

src/Type/Php/ClosureBindDynamicReturnTypeExtension.php

@@ -9,7 +9,9 @@
 use PHPStan\Reflection\MethodReflection;
 use PHPStan\Type\ClosureType;
 use PHPStan\Type\DynamicStaticMethodReturnTypeExtension;
+use PHPStan\Type\NullType;
 use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
 
 #[AutowiredService]
 final class ClosureBindDynamicReturnTypeExtension implements DynamicStaticMethodReturnTypeExtension
@@ -32,6 +34,14 @@ public function getTypeFromStaticMethodCall(MethodReflection $methodReflection,
 			return null;
 		}
 
+		if ($closureType->isStaticClosure()->yes()) {
+			return new NullType();
+		}
+
+		if ($closureType->isStaticClosure()->maybe()) {
+			return TypeCombinator::union($closureType, new NullType());
+		}
+
 		return $closureType;
 	}
 

src/Type/Php/ClosureBindToDynamicReturnTypeExtension.php

@@ -9,7 +9,9 @@
 use PHPStan\Reflection\MethodReflection;
 use PHPStan\Type\ClosureType;
 use PHPStan\Type\DynamicMethodReturnTypeExtension;
+use PHPStan\Type\NullType;
 use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
 
 #[AutowiredService]
 final class ClosureBindToDynamicReturnTypeExtension implements DynamicMethodReturnTypeExtension
@@ -32,6 +34,14 @@ public function getTypeFromMethodCall(MethodReflection $methodReflection, Method
 			return null;
 		}
 
+		if ($closureType->isStaticClosure()->yes()) {
+			return new NullType();
+		}
+
+		if ($closureType->isStaticClosure()->maybe()) {
+			return TypeCombinator::union($closureType, new NullType());
+		}
+
 		return $closureType;
 	}
 

src/Type/Php/ClosureFromCallableDynamicReturnTypeExtension.php

@@ -56,6 +56,7 @@ public function getTypeFromStaticMethodCall(MethodReflection $methodReflection,
 				usedVariables: $variant->getUsedVariables(),
 				acceptsNamedArguments: $variant->acceptsNamedArguments(),
 				mustUseReturnValue: $variant->mustUseReturnValue(),
+				isStatic: $variant->isStaticClosure(),
 			);
 		}