diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 4b4096c92c..e75ce4046b 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -1077,6 +1077,12 @@ parameters:
 			count: 2
 			path: src/Type/Enum/EnumCaseObjectType.php
 
+		-
+			rawMessage: 'Doing instanceof PHPStan\Type\ErrorType is error-prone and deprecated. Use Type::isError() instead.'
+			identifier: phpstanApi.instanceofType
+			count: 1
+			path: src/Type/ErrorType.php
+
 		-
 			rawMessage: 'Doing instanceof PHPStan\Type\ConstantScalarType is error-prone and deprecated. Use Type::isConstantScalarValue() or Type::getConstantScalarTypes() or Type::getConstantScalarValues() instead.'
 			identifier: phpstanApi.instanceofType
@@ -1479,6 +1485,12 @@ parameters:
 			count: 1
 			path: src/Type/ObjectType.php
 
+		-
+			rawMessage: 'Doing instanceof PHPStan\Type\ErrorType is error-prone and deprecated. Use Type::isError() instead.'
+			identifier: phpstanApi.instanceofType
+			count: 4
+			path: src/Type/ObjectType.php
+
 		-
 			rawMessage: Doing instanceof PHPStan\Type\Generic\GenericObjectType is error-prone and deprecated.
 			identifier: phpstanApi.instanceofType
diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index 65a2969f90..d813a4dd19 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -1800,7 +1800,7 @@ static function (Node $node, Scope $scope) use ($arrowScope, &$arrowFunctionImpu
 
 			$returnType = $functionReflection->getReturnType();
 			$generatorSendType = $returnType->getTemplateType(Generator::class, 'TSend');
-			if ($generatorSendType instanceof ErrorType) {
+			if ($generatorSendType->isError()->yes()) {
 				return new MixedType();
 			}
 
@@ -1808,7 +1808,7 @@ static function (Node $node, Scope $scope) use ($arrowScope, &$arrowFunctionImpu
 		} elseif ($node instanceof Expr\YieldFrom) {
 			$yieldFromType = $this->getType($node->expr);
 			$generatorReturnType = $yieldFromType->getTemplateType(Generator::class, 'TReturn');
-			if ($generatorReturnType instanceof ErrorType) {
+			if ($generatorReturnType->isError()->yes()) {
 				return new MixedType();
 			}
 
@@ -6040,7 +6040,7 @@ classReflection: $classReflection->withTypes($types)->asFinal(),
 		return TypeTraverser::map($newGenericType, static function (Type $type, callable $traverse) use ($resolvedTemplateTypeMap): Type {
 			if ($type instanceof TemplateType && !$type->isArgument()) {
 				$newType = $resolvedTemplateTypeMap->getType($type->getName());
-				if ($newType === null || $newType instanceof ErrorType) {
+				if ($newType === null || $newType->isError()->yes()) {
 					return $type->getDefault() ?? $type->getBound();
 				}
 
diff --git a/src/Reflection/ClassReflection.php b/src/Reflection/ClassReflection.php
index b6e2f2e908..cbb1fd1ae8 100644
--- a/src/Reflection/ClassReflection.php
+++ b/src/Reflection/ClassReflection.php
@@ -1643,7 +1643,7 @@ public function getActiveTemplateTypeMap(): TemplateTypeMap
 		if ($resolved !== null) {
 			$templateTypeMap = $this->getTemplateTypeMap();
 			return $this->activeTemplateTypeMap = $resolved->map(static function (string $name, Type $type) use ($templateTypeMap): Type {
-				if ($type instanceof ErrorType) {
+				if ($type->isError()->yes()) {
 					$templateType = $templateTypeMap->getType($name);
 					if ($templateType !== null) {
 						return TemplateTypeHelper::resolveToDefaults($templateType);
diff --git a/src/Reflection/InitializerExprTypeResolver.php b/src/Reflection/InitializerExprTypeResolver.php
index 47157cf01a..c3ae1bb05b 100644
--- a/src/Reflection/InitializerExprTypeResolver.php
+++ b/src/Reflection/InitializerExprTypeResolver.php
@@ -518,7 +518,7 @@ public function resolveConcatType(Type $left, Type $right): Type
 		if (TypeCombinator::union(
 			$leftStringType,
 			$rightStringType,
-		) instanceof ErrorType) {
+		)->isError()->yes()) {
 			return new ErrorType();
 		}
 
@@ -974,7 +974,7 @@ public function getBitwiseAndType(Expr $left, Expr $right, callable $getTypeCall
 							$leftNumberType = $leftTypeInner->toNumber();
 							$rightNumberType = $rightTypeInner->toNumber();
 
-							if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+							if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 								return new ErrorType();
 							}
 
@@ -1001,7 +1001,7 @@ public function getBitwiseAndType(Expr $left, Expr $right, callable $getTypeCall
 		$leftNumberType = $leftType->toNumber();
 		$rightNumberType = $rightType->toNumber();
 
-		if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+		if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 			return new ErrorType();
 		}
 
@@ -1043,7 +1043,7 @@ public function getBitwiseOrType(Expr $left, Expr $right, callable $getTypeCallb
 							$leftNumberType = $leftTypeInner->toNumber();
 							$rightNumberType = $rightTypeInner->toNumber();
 
-							if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+							if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 								return new ErrorType();
 							}
 
@@ -1067,7 +1067,7 @@ public function getBitwiseOrType(Expr $left, Expr $right, callable $getTypeCallb
 			return new StringType();
 		}
 
-		if (TypeCombinator::union($leftType->toNumber(), $rightType->toNumber()) instanceof ErrorType) {
+		if (TypeCombinator::union($leftType->toNumber(), $rightType->toNumber())->isError()->yes()) {
 			return new ErrorType();
 		}
 
@@ -1102,7 +1102,7 @@ public function getBitwiseXorType(Expr $left, Expr $right, callable $getTypeCall
 							$leftNumberType = $leftTypeInner->toNumber();
 							$rightNumberType = $rightTypeInner->toNumber();
 
-							if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+							if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 								return new ErrorType();
 							}
 
@@ -1126,7 +1126,7 @@ public function getBitwiseXorType(Expr $left, Expr $right, callable $getTypeCall
 			return new StringType();
 		}
 
-		if (TypeCombinator::union($leftType->toNumber(), $rightType->toNumber()) instanceof ErrorType) {
+		if (TypeCombinator::union($leftType->toNumber(), $rightType->toNumber())->isError()->yes()) {
 			return new ErrorType();
 		}
 
@@ -1187,7 +1187,7 @@ public function getDivType(Expr $left, Expr $right, callable $getTypeCallback):
 						$leftNumberType = $leftTypeInner->toNumber();
 						$rightNumberType = $rightTypeInner->toNumber();
 
-						if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+						if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 							return new ErrorType();
 						}
 
@@ -1238,7 +1238,7 @@ public function getModType(Expr $left, Expr $right, callable $getTypeCallback):
 			return $extensionSpecified;
 		}
 
-		if ($leftType->toNumber() instanceof ErrorType || $rightType->toNumber() instanceof ErrorType) {
+		if ($leftType->toNumber()->isError()->yes() || $rightType->toNumber()->isError()->yes()) {
 			return new ErrorType();
 		}
 
@@ -1255,7 +1255,7 @@ public function getModType(Expr $left, Expr $right, callable $getTypeCallback):
 						$leftNumberType = $leftTypeInner->toNumber();
 						$rightNumberType = $rightTypeInner->toNumber();
 
-						if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+						if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 							return new ErrorType();
 						}
 
@@ -1354,7 +1354,7 @@ public function getPlusType(Expr $left, Expr $right, callable $getTypeCallback):
 						$leftNumberType = $leftTypeInner->toNumber();
 						$rightNumberType = $rightTypeInner->toNumber();
 
-						if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+						if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 							return new ErrorType();
 						}
 
@@ -1533,7 +1533,7 @@ public function getMinusType(Expr $left, Expr $right, callable $getTypeCallback)
 						$leftNumberType = $leftTypeInner->toNumber();
 						$rightNumberType = $rightTypeInner->toNumber();
 
-						if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+						if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 							return new ErrorType();
 						}
 
@@ -1577,7 +1577,7 @@ public function getMulType(Expr $left, Expr $right, callable $getTypeCallback):
 						$leftNumberType = $leftTypeInner->toNumber();
 						$rightNumberType = $rightTypeInner->toNumber();
 
-						if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+						if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 							return new ErrorType();
 						}
 
@@ -1630,7 +1630,7 @@ public function getPowType(Expr $left, Expr $right, callable $getTypeCallback):
 		}
 
 		$exponentiatedTyped = $leftType->exponentiate($rightType);
-		if (!$exponentiatedTyped instanceof ErrorType) {
+		if (!$exponentiatedTyped->isError()->yes()) {
 			return $exponentiatedTyped;
 		}
 
@@ -1662,7 +1662,7 @@ public function getShiftLeftType(Expr $left, Expr $right, callable $getTypeCallb
 						$leftNumberType = $leftTypeInner->toNumber();
 						$rightNumberType = $rightTypeInner->toNumber();
 
-						if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+						if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 							return new ErrorType();
 						}
 
@@ -1689,7 +1689,7 @@ public function getShiftLeftType(Expr $left, Expr $right, callable $getTypeCallb
 		$leftNumberType = $leftType->toNumber();
 		$rightNumberType = $rightType->toNumber();
 
-		if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+		if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 			return new ErrorType();
 		}
 
@@ -1721,7 +1721,7 @@ public function getShiftRightType(Expr $left, Expr $right, callable $getTypeCall
 						$leftNumberType = $leftTypeInner->toNumber();
 						$rightNumberType = $rightTypeInner->toNumber();
 
-						if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+						if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 							return new ErrorType();
 						}
 
@@ -1748,7 +1748,7 @@ public function getShiftRightType(Expr $left, Expr $right, callable $getTypeCall
 		$leftNumberType = $leftType->toNumber();
 		$rightNumberType = $rightType->toNumber();
 
-		if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+		if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 			return new ErrorType();
 		}
 
@@ -1966,7 +1966,7 @@ private function resolveCommonMath(Expr\BinaryOp $expr, Type $leftType, Type $ri
 			return new ErrorType();
 		}
 
-		if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
+		if ($leftNumberType->isError()->yes() || $rightNumberType->isError()->yes()) {
 			return new ErrorType();
 		}
 		if ($leftNumberType instanceof NeverType || $rightNumberType instanceof NeverType) {
diff --git a/src/Reflection/Php/PhpClassReflectionExtension.php b/src/Reflection/Php/PhpClassReflectionExtension.php
index 37959a7a64..0f8bd0190d 100644
--- a/src/Reflection/Php/PhpClassReflectionExtension.php
+++ b/src/Reflection/Php/PhpClassReflectionExtension.php
@@ -41,7 +41,6 @@
 use PHPStan\Type\Constant\ConstantArrayTypeBuilder;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\Enum\EnumCaseObjectType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\FileTypeMapper;
 use PHPStan\Type\GeneralizePrecision;
 use PHPStan\Type\Generic\TemplateMixedType;
@@ -1161,7 +1160,7 @@ private function inferAndCachePropertyTypes(
 			}
 
 			$propertyType = $methodScope->getType($expr->expr);
-			if ($propertyType instanceof ErrorType || $propertyType instanceof NeverType) {
+			if ($propertyType->isError()->yes() || $propertyType instanceof NeverType) {
 				continue;
 			}
 
diff --git a/src/Reflection/ResolvedFunctionVariantWithOriginal.php b/src/Reflection/ResolvedFunctionVariantWithOriginal.php
index 21108d658e..4a02b9e80c 100644
--- a/src/Reflection/ResolvedFunctionVariantWithOriginal.php
+++ b/src/Reflection/ResolvedFunctionVariantWithOriginal.php
@@ -4,7 +4,6 @@
 
 use PHPStan\Reflection\Php\ExtendedDummyParameter;
 use PHPStan\Type\ConditionalTypeForParameter;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Generic\GenericObjectType;
 use PHPStan\Type\Generic\GenericStaticType;
 use PHPStan\Type\Generic\TemplateType;
@@ -211,7 +210,7 @@ private function resolveResolvableTemplateTypes(Type $type, TemplateTypeVariance
 				&& $type->getScope()->getFunctionName() !== null
 			) {
 				$newType = $this->resolvedTemplateTypeMap->getType($type->getName());
-				if ($newType === null || $newType instanceof ErrorType) {
+				if ($newType === null || $newType->isError()->yes()) {
 					return $traverse($type);
 				}
 
@@ -252,7 +251,7 @@ private function resolveResolvableTemplateTypes(Type $type, TemplateTypeVariance
 
 			if ($type instanceof TemplateType && !$type->isArgument()) {
 				$newType = $this->resolvedTemplateTypeMap->getType($type->getName());
-				if ($newType === null || $newType instanceof ErrorType) {
+				if ($newType === null || $newType->isError()->yes()) {
 					return $traverse($type);
 				}
 
diff --git a/src/Rules/Api/ApiInstanceofTypeRule.php b/src/Rules/Api/ApiInstanceofTypeRule.php
index c88c5114bf..e633c57523 100644
--- a/src/Rules/Api/ApiInstanceofTypeRule.php
+++ b/src/Rules/Api/ApiInstanceofTypeRule.php
@@ -32,6 +32,7 @@
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\ConstantScalarType;
 use PHPStan\Type\Enum\EnumCaseObjectType;
+use PHPStan\Type\ErrorType;
 use PHPStan\Type\FloatType;
 use PHPStan\Type\Generic\GenericClassStringType;
 use PHPStan\Type\Generic\GenericObjectType;
@@ -79,6 +80,7 @@ final class ApiInstanceofTypeRule implements Rule
 		IntersectionType::class => null,
 		ConstantScalarType::class => 'Type::isConstantScalarValue() or Type::getConstantScalarTypes() or Type::getConstantScalarValues()',
 		ObjectShapeType::class => 'Type::isObject() and Type::hasProperty()',
+		ErrorType::class => 'Type::isError()',
 
 		// accessory types
 		NonEmptyArrayType::class => 'Type::isIterableAtLeastOnce()',
diff --git a/src/Rules/Arrays/ArrayDestructuringRule.php b/src/Rules/Arrays/ArrayDestructuringRule.php
index eac1a12956..9ea574ca5b 100644
--- a/src/Rules/Arrays/ArrayDestructuringRule.php
+++ b/src/Rules/Arrays/ArrayDestructuringRule.php
@@ -14,7 +14,6 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\Type\Constant\ConstantIntegerType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
@@ -65,7 +64,7 @@ private function getErrors(Scope $scope, Node\Expr\List_ $var, Expr $expr): arra
 			static fn (Type $varType): bool => $varType->isArray()->yes() || (new ObjectType(ArrayAccess::class))->isSuperTypeOf($varType)->yes(),
 		);
 		$exprType = $exprTypeResult->getType();
-		if ($exprType instanceof ErrorType) {
+		if ($exprType->isError()->yes()) {
 			return [];
 		}
 		if (!$exprType->isArray()->yes() && !(new ObjectType(ArrayAccess::class))->isSuperTypeOf($exprType)->yes()) {
diff --git a/src/Rules/Arrays/ArrayUnpackingRule.php b/src/Rules/Arrays/ArrayUnpackingRule.php
index 4dc25092a9..496d137296 100644
--- a/src/Rules/Arrays/ArrayUnpackingRule.php
+++ b/src/Rules/Arrays/ArrayUnpackingRule.php
@@ -11,7 +11,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -46,7 +45,7 @@ public function processNode(Node $node, Scope $scope): array
 		);
 
 		$keyType = $typeResult->getType();
-		if ($keyType instanceof ErrorType) {
+		if ($keyType->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 
diff --git a/src/Rules/Arrays/InvalidKeyInArrayDimFetchRule.php b/src/Rules/Arrays/InvalidKeyInArrayDimFetchRule.php
index 0723234b36..0ceca79417 100644
--- a/src/Rules/Arrays/InvalidKeyInArrayDimFetchRule.php
+++ b/src/Rules/Arrays/InvalidKeyInArrayDimFetchRule.php
@@ -10,7 +10,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -49,7 +48,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $varType): bool => $varType->isArray()->no(),
 		)->getType();
 
-		if ($varType instanceof ErrorType) {
+		if ($varType->isError()->yes()) {
 			return [];
 		}
 
@@ -65,7 +64,7 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			static fn (Type $dimType): bool => $allowedArrayKeys->isSuperTypeOf($dimType)->yes(),
 		)->getType();
-		if ($dimensionType instanceof ErrorType) {
+		if ($dimensionType->isError()->yes()) {
 			return [];
 		}
 
diff --git a/src/Rules/Arrays/InvalidKeyInArrayItemRule.php b/src/Rules/Arrays/InvalidKeyInArrayItemRule.php
index 298c65b565..d3b28c8450 100644
--- a/src/Rules/Arrays/InvalidKeyInArrayItemRule.php
+++ b/src/Rules/Arrays/InvalidKeyInArrayItemRule.php
@@ -9,7 +9,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -46,7 +45,7 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			static fn (Type $dimType): bool => $allowedArrayKeys->isSuperTypeOf($dimType)->yes(),
 		)->getType();
-		if ($dimensionType instanceof ErrorType) {
+		if ($dimensionType->isError()->yes()) {
 			return [];
 		}
 
diff --git a/src/Rules/Arrays/IterableInForeachRule.php b/src/Rules/Arrays/IterableInForeachRule.php
index 2e4204b35b..68243b8396 100644
--- a/src/Rules/Arrays/IterableInForeachRule.php
+++ b/src/Rules/Arrays/IterableInForeachRule.php
@@ -9,7 +9,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -40,7 +39,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $type): bool => $type->isIterable()->yes(),
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 		if ($type->isIterable()->yes()) {
diff --git a/src/Rules/Arrays/NonexistentOffsetInArrayDimFetchCheck.php b/src/Rules/Arrays/NonexistentOffsetInArrayDimFetchCheck.php
index 3e4b1e7b3f..46a24ac5f4 100644
--- a/src/Rules/Arrays/NonexistentOffsetInArrayDimFetchCheck.php
+++ b/src/Rules/Arrays/NonexistentOffsetInArrayDimFetchCheck.php
@@ -11,7 +11,6 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\Type\BenevolentUnionType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
@@ -54,7 +53,7 @@ public function check(
 			static fn (Type $type): bool => $type->hasOffsetValueType($dimType)->yes(),
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 
diff --git a/src/Rules/Arrays/NonexistentOffsetInArrayDimFetchRule.php b/src/Rules/Arrays/NonexistentOffsetInArrayDimFetchRule.php
index 9a4947d521..a3485c7148 100644
--- a/src/Rules/Arrays/NonexistentOffsetInArrayDimFetchRule.php
+++ b/src/Rules/Arrays/NonexistentOffsetInArrayDimFetchRule.php
@@ -15,7 +15,6 @@
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\Constant\ConstantIntegerType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function count;
@@ -65,7 +64,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $type): bool => $type->isOffsetAccessible()->yes(),
 		);
 		$isOffsetAccessibleType = $isOffsetAccessibleTypeResult->getType();
-		if ($isOffsetAccessibleType instanceof ErrorType) {
+		if ($isOffsetAccessibleType->isError()->yes()) {
 			return $isOffsetAccessibleTypeResult->getUnknownClassErrors();
 		}
 
diff --git a/src/Rules/Arrays/OffsetAccessAssignOpRule.php b/src/Rules/Arrays/OffsetAccessAssignOpRule.php
index 466d5cd5c8..eac6c16f7b 100644
--- a/src/Rules/Arrays/OffsetAccessAssignOpRule.php
+++ b/src/Rules/Arrays/OffsetAccessAssignOpRule.php
@@ -9,7 +9,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
@@ -50,7 +49,7 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			static function (Type $varType) use ($potentialDimType): bool {
 				$arrayDimType = $varType->setOffsetValueType($potentialDimType, new MixedType());
-				return !($arrayDimType instanceof ErrorType);
+				return !($arrayDimType->isError()->yes());
 			},
 		);
 		$varType = $varTypeResult->getType();
@@ -62,7 +61,7 @@ static function (Type $varType) use ($potentialDimType): bool {
 				'',
 				static function (Type $dimType) use ($varType): bool {
 					$arrayDimType = $varType->setOffsetValueType($dimType, new MixedType());
-					return !($arrayDimType instanceof ErrorType);
+					return !($arrayDimType->isError()->yes());
 				},
 			);
 			$dimType = $dimTypeResult->getType();
@@ -74,7 +73,7 @@ static function (Type $dimType) use ($varType): bool {
 		}
 
 		$resultType = $varType->setOffsetValueType($dimType, new MixedType());
-		if (!($resultType instanceof ErrorType)) {
+		if (!($resultType->isError()->yes())) {
 			return [];
 		}
 
diff --git a/src/Rules/Arrays/OffsetAccessAssignmentRule.php b/src/Rules/Arrays/OffsetAccessAssignmentRule.php
index 838636feb6..adb030d2d9 100644
--- a/src/Rules/Arrays/OffsetAccessAssignmentRule.php
+++ b/src/Rules/Arrays/OffsetAccessAssignmentRule.php
@@ -9,7 +9,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
@@ -48,11 +47,11 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			static function (Type $varType) use ($potentialDimType): bool {
 				$arrayDimType = $varType->setOffsetValueType($potentialDimType, new MixedType());
-				return !($arrayDimType instanceof ErrorType);
+				return !($arrayDimType->isError()->yes());
 			},
 		);
 		$varType = $varTypeResult->getType();
-		if ($varType instanceof ErrorType) {
+		if ($varType->isError()->yes()) {
 			return [];
 		}
 		if (!$varType->isOffsetAccessible()->yes()) {
@@ -66,7 +65,7 @@ static function (Type $varType) use ($potentialDimType): bool {
 				'',
 				static function (Type $dimType) use ($varType): bool {
 					$arrayDimType = $varType->setOffsetValueType($dimType, new MixedType());
-					return !($arrayDimType instanceof ErrorType);
+					return !($arrayDimType->isError()->yes());
 				},
 			);
 			$dimType = $dimTypeResult->getType();
@@ -75,7 +74,7 @@ static function (Type $dimType) use ($varType): bool {
 		}
 
 		$resultType = $varType->setOffsetValueType($dimType, new MixedType());
-		if (!($resultType instanceof ErrorType)) {
+		if (!($resultType->isError()->yes())) {
 			return [];
 		}
 
diff --git a/src/Rules/Arrays/OffsetAccessValueAssignmentRule.php b/src/Rules/Arrays/OffsetAccessValueAssignmentRule.php
index 3d21a95970..f538a334a3 100644
--- a/src/Rules/Arrays/OffsetAccessValueAssignmentRule.php
+++ b/src/Rules/Arrays/OffsetAccessValueAssignmentRule.php
@@ -11,7 +11,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
@@ -65,11 +64,11 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			static function (Type $varType) use ($assignedValueType): bool {
 				$result = $varType->setOffsetValueType(new MixedType(), $assignedValueType);
-				return !($result instanceof ErrorType);
+				return !($result->isError()->yes());
 			},
 		);
 		$arrayType = $arrayTypeResult->getType();
-		if ($arrayType instanceof ErrorType) {
+		if ($arrayType->isError()->yes()) {
 			return [];
 		}
 		$isOffsetAccessible = $arrayType->isOffsetAccessible();
@@ -77,7 +76,7 @@ static function (Type $varType) use ($assignedValueType): bool {
 			return [];
 		}
 		$resultType = $arrayType->setOffsetValueType(new MixedType(), $assignedValueType);
-		if (!$resultType instanceof ErrorType) {
+		if (!$resultType->isError()->yes()) {
 			return [];
 		}
 
diff --git a/src/Rules/Arrays/UnpackIterableInArrayRule.php b/src/Rules/Arrays/UnpackIterableInArrayRule.php
index 0e7907b59d..c123ad7c4c 100644
--- a/src/Rules/Arrays/UnpackIterableInArrayRule.php
+++ b/src/Rules/Arrays/UnpackIterableInArrayRule.php
@@ -9,7 +9,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -51,7 +50,7 @@ public function processNode(Node $node, Scope $scope): array
 				static fn (Type $type): bool => $type->isIterable()->yes(),
 			);
 			$type = $typeResult->getType();
-			if ($type instanceof ErrorType) {
+			if ($type->isError()->yes()) {
 				continue;
 			}
 
diff --git a/src/Rules/Cast/EchoRule.php b/src/Rules/Cast/EchoRule.php
index 4844d1e0a0..442e52cefc 100644
--- a/src/Rules/Cast/EchoRule.php
+++ b/src/Rules/Cast/EchoRule.php
@@ -8,7 +8,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -38,11 +37,11 @@ public function processNode(Node $node, Scope $scope): array
 				$scope,
 				$expr,
 				'',
-				static fn (Type $type): bool => !$type->toString() instanceof ErrorType,
+				static fn (Type $type): bool => !$type->toString()->isError()->yes(),
 			);
 
-			if ($typeResult->getType() instanceof ErrorType
-				|| !$typeResult->getType()->toString() instanceof ErrorType
+			if ($typeResult->getType()->isError()->yes()
+				|| !$typeResult->getType()->toString()->isError()->yes()
 			) {
 				continue;
 			}
diff --git a/src/Rules/Cast/InvalidCastRule.php b/src/Rules/Cast/InvalidCastRule.php
index 38b97e396a..af5b7956a0 100644
--- a/src/Rules/Cast/InvalidCastRule.php
+++ b/src/Rules/Cast/InvalidCastRule.php
@@ -9,7 +9,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function get_class;
@@ -64,11 +63,11 @@ static function (Type $type) use ($castTypeCallback): bool {
 
 				[$castType] = $castResult;
 
-				return !$castType instanceof ErrorType;
+				return !$castType->isError()->yes();
 			},
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return [];
 		}
 
@@ -79,7 +78,7 @@ static function (Type $type) use ($castTypeCallback): bool {
 
 		[$castType, $castIdentifier] = $castResult;
 
-		if ($castType instanceof ErrorType) {
+		if ($castType->isError()->yes()) {
 			$classReflection = $this->reflectionProvider->getClass(get_class($node));
 			$shortName = $classReflection->getNativeReflection()->getShortName();
 			$shortName = strtolower($shortName);
diff --git a/src/Rules/Cast/InvalidPartOfEncapsedStringRule.php b/src/Rules/Cast/InvalidPartOfEncapsedStringRule.php
index d8d899e72d..a404cd3659 100644
--- a/src/Rules/Cast/InvalidPartOfEncapsedStringRule.php
+++ b/src/Rules/Cast/InvalidPartOfEncapsedStringRule.php
@@ -9,7 +9,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -45,15 +44,15 @@ public function processNode(Node $node, Scope $scope): array
 				$scope,
 				$part,
 				'',
-				static fn (Type $type): bool => !$type->toString() instanceof ErrorType,
+				static fn (Type $type): bool => !$type->toString()->isError()->yes(),
 			);
 			$partType = $typeResult->getType();
-			if ($partType instanceof ErrorType) {
+			if ($partType->isError()->yes()) {
 				continue;
 			}
 
 			$stringPartType = $partType->toString();
-			if (!$stringPartType instanceof ErrorType) {
+			if (!$stringPartType->isError()->yes()) {
 				continue;
 			}
 			$messages[] = RuleErrorBuilder::message(sprintf(
diff --git a/src/Rules/Cast/PrintRule.php b/src/Rules/Cast/PrintRule.php
index 8e881f8ba3..5b049c844e 100644
--- a/src/Rules/Cast/PrintRule.php
+++ b/src/Rules/Cast/PrintRule.php
@@ -8,7 +8,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -35,11 +34,11 @@ public function processNode(Node $node, Scope $scope): array
 			$scope,
 			$node->expr,
 			'',
-			static fn (Type $type): bool => !$type->toString() instanceof ErrorType,
+			static fn (Type $type): bool => !$type->toString()->isError()->yes(),
 		);
 
-		if (!$typeResult->getType() instanceof ErrorType
-			&& $typeResult->getType()->toString() instanceof ErrorType
+		if (!$typeResult->getType()->isError()->yes()
+			&& $typeResult->getType()->toString()->isError()->yes()
 		) {
 			return [RuleErrorBuilder::message(sprintf(
 				'Parameter %s of print cannot be converted to string.',
diff --git a/src/Rules/Classes/ClassConstantRule.php b/src/Rules/Classes/ClassConstantRule.php
index a8220d5e11..ccca894bce 100644
--- a/src/Rules/Classes/ClassConstantRule.php
+++ b/src/Rules/Classes/ClassConstantRule.php
@@ -21,7 +21,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\StringType;
 use PHPStan\Type\ThisType;
 use PHPStan\Type\Type;
@@ -77,7 +76,7 @@ public function processNode(Node $node, Scope $scope): array
 				);
 
 				$nameType = $nameTypeResult->getType();
-				if (!$nameType instanceof ErrorType && !$nameType->isString()->yes()) {
+				if (!$nameType->isError()->yes() && !$nameType->isString()->yes()) {
 					$className = $node->class instanceof Name
 						? $scope->resolveName($node->class)
 						: $scope->getType($node->class)->describe(VerbosityLevel::typeOnly());
@@ -205,7 +204,7 @@ private function processSingleClassConstFetch(Scope $scope, ClassConstFetch $nod
 				static fn (Type $type): bool => $type->canAccessConstants()->yes() && $type->hasConstant($constantName)->yes(),
 			);
 			$classType = $classTypeResult->getType();
-			if ($classType instanceof ErrorType) {
+			if ($classType->isError()->yes()) {
 				return $classTypeResult->getUnknownClassErrors();
 			}
 
diff --git a/src/Rules/Classes/ImpossibleInstanceOfRule.php b/src/Rules/Classes/ImpossibleInstanceOfRule.php
index 7c866cc30e..83b8d5d70d 100644
--- a/src/Rules/Classes/ImpossibleInstanceOfRule.php
+++ b/src/Rules/Classes/ImpossibleInstanceOfRule.php
@@ -11,7 +11,6 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\Type\Constant\ConstantBooleanType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\ObjectWithoutClassType;
 use PHPStan\Type\StringType;
@@ -61,7 +60,7 @@ public function processNode(Node $node, Scope $scope): array
 				'',
 				static fn (Type $type): bool => !$allowed->isSuperTypeOf($type)->yes(),
 			);
-			if (!$typeResult->getType() instanceof ErrorType && !$allowed->isSuperTypeOf($typeResult->getType())->yes()) {
+			if (!$typeResult->getType()->isError()->yes() && !$allowed->isSuperTypeOf($typeResult->getType())->yes()) {
 				return [
 					RuleErrorBuilder::message(sprintf(
 						'Instanceof between %s and %s results in an error.',
diff --git a/src/Rules/Classes/LocalTypeAliasesCheck.php b/src/Rules/Classes/LocalTypeAliasesCheck.php
index a849ecac8c..a14547c029 100644
--- a/src/Rules/Classes/LocalTypeAliasesCheck.php
+++ b/src/Rules/Classes/LocalTypeAliasesCheck.php
@@ -21,7 +21,6 @@
 use PHPStan\Rules\PhpDoc\UnresolvableTypeHelper;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Type\CircularTypeAliasErrorType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Generic\TemplateType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeTraverser;
@@ -359,7 +358,7 @@ private function hasErrorType(Type $type, string $aliasName, array &$errors): bo
 				return $type;
 			}
 
-			if ($type instanceof ErrorType) {
+			if ($type->isError()->yes()) {
 				$errors[] = RuleErrorBuilder::message(sprintf('Invalid type definition detected in type alias %s.', $aliasName))
 					->identifier('typeAlias.invalidType')
 					->build();
diff --git a/src/Rules/Constants/DynamicClassConstantFetchRule.php b/src/Rules/Constants/DynamicClassConstantFetchRule.php
index 62046c1b50..c1a6970896 100644
--- a/src/Rules/Constants/DynamicClassConstantFetchRule.php
+++ b/src/Rules/Constants/DynamicClassConstantFetchRule.php
@@ -10,7 +10,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -53,7 +52,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $type): bool => $type->isString()->yes(),
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return [];
 		}
 		if ($type->isString()->yes()) {
diff --git a/src/Rules/Exceptions/ThrowExprTypeRule.php b/src/Rules/Exceptions/ThrowExprTypeRule.php
index e2b0debb30..347b9fdc18 100644
--- a/src/Rules/Exceptions/ThrowExprTypeRule.php
+++ b/src/Rules/Exceptions/ThrowExprTypeRule.php
@@ -8,7 +8,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
@@ -44,7 +43,7 @@ public function processNode(Node $node, Scope $scope): array
 		);
 
 		$foundType = $typeResult->getType();
-		if ($foundType instanceof ErrorType) {
+		if ($foundType->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 
diff --git a/src/Rules/FunctionCallParametersCheck.php b/src/Rules/FunctionCallParametersCheck.php
index 5cb8b48761..9dcfc5385a 100644
--- a/src/Rules/FunctionCallParametersCheck.php
+++ b/src/Rules/FunctionCallParametersCheck.php
@@ -18,7 +18,6 @@
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\ConditionalType;
 use PHPStan\Type\Constant\ConstantIntegerType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Generic\TemplateType;
 use PHPStan\Type\IntegerRangeType;
 use PHPStan\Type\NeverType;
@@ -302,7 +301,7 @@ public function check(
 				);
 				$iterableTypeResultType = $iterableTypeResult->getType();
 				if (
-					!$iterableTypeResultType instanceof ErrorType
+					!$iterableTypeResultType->isError()->yes()
 					&& !$iterableTypeResultType->isIterable()->yes()
 				) {
 					$errors[] = RuleErrorBuilder::message(sprintf(
@@ -351,7 +350,7 @@ public function check(
 
 				if (
 					!$parameter->passedByReference()->createsNewVariable()
-					|| (!$isBuiltin && !$argumentValueType instanceof ErrorType)
+					|| (!$isBuiltin && !$argumentValueType->isError()->yes())
 				) {
 					$accepts = $this->ruleLevelHelper->accepts($parameterType, $argumentValueType, $scope->isDeclareStrictTypes());
 
@@ -501,7 +500,7 @@ static function (Type $type, callable $traverse) use (&$returnTemplateTypes): Ty
 
 				foreach ($resolvedTypes as $name => $type) {
 					if (
-						!($type instanceof ErrorType)
+						!($type->isError()->yes())
 						&& (
 							!$type instanceof NeverType
 							|| $type->isExplicit()
diff --git a/src/Rules/FunctionReturnTypeCheck.php b/src/Rules/FunctionReturnTypeCheck.php
index e61965ca3a..b371f75cb3 100644
--- a/src/Rules/FunctionReturnTypeCheck.php
+++ b/src/Rules/FunctionReturnTypeCheck.php
@@ -7,7 +7,6 @@
 use PhpParser\Node\Expr;
 use PHPStan\Analyser\Scope;
 use PHPStan\DependencyInjection\AutowiredService;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeUtils;
@@ -50,7 +49,7 @@ public function checkReturnType(
 
 		if ($isGenerator) {
 			$returnType = $returnType->getTemplateType(Generator::class, 'TReturn');
-			if ($returnType instanceof ErrorType) {
+			if ($returnType->isError()->yes()) {
 				return [];
 			}
 		}
diff --git a/src/Rules/Functions/CallCallablesRule.php b/src/Rules/Functions/CallCallablesRule.php
index 4ab0af4b01..54045ae260 100644
--- a/src/Rules/Functions/CallCallablesRule.php
+++ b/src/Rules/Functions/CallCallablesRule.php
@@ -16,7 +16,6 @@
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\ClosureType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function array_merge;
@@ -61,7 +60,7 @@ public function processNode(
 			static fn (Type $type): bool => $type->isCallable()->yes(),
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 
diff --git a/src/Rules/Functions/FunctionCallableRule.php b/src/Rules/Functions/FunctionCallableRule.php
index a4b698d357..5ea97e6c84 100644
--- a/src/Rules/Functions/FunctionCallableRule.php
+++ b/src/Rules/Functions/FunctionCallableRule.php
@@ -13,7 +13,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -98,7 +97,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $type): bool => $type->isCallable()->yes(),
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 
diff --git a/src/Rules/Functions/PrintfParameterTypeRule.php b/src/Rules/Functions/PrintfParameterTypeRule.php
index 68b79d0f00..8ae2624ac6 100644
--- a/src/Rules/Functions/PrintfParameterTypeRule.php
+++ b/src/Rules/Functions/PrintfParameterTypeRule.php
@@ -10,7 +10,6 @@
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\BooleanType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\FloatType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\NullType;
@@ -130,7 +129,7 @@ public function processNode(Node $node, Scope $scope): array
 					fn (Type $t) => $placeholder->doesArgumentTypeMatchPlaceholder($t, $this->checkStrictPrintfPlaceholderTypes),
 				)->getType();
 
-				if ($argType instanceof ErrorType || $placeholder->doesArgumentTypeMatchPlaceholder($argType, $this->checkStrictPrintfPlaceholderTypes)) {
+				if ($argType->isError()->yes() || $placeholder->doesArgumentTypeMatchPlaceholder($argType, $this->checkStrictPrintfPlaceholderTypes)) {
 					continue;
 				}
 
diff --git a/src/Rules/Functions/PrintfPlaceholder.php b/src/Rules/Functions/PrintfPlaceholder.php
index c151395308..883c78430c 100644
--- a/src/Rules/Functions/PrintfPlaceholder.php
+++ b/src/Rules/Functions/PrintfPlaceholder.php
@@ -4,7 +4,6 @@
 
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\Accessory\AccessoryNumericStringType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\FloatType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\IntersectionType;
@@ -35,7 +34,7 @@ public function doesArgumentTypeMatchPlaceholder(Type $argumentType, bool $stric
 			case 'int':
 				return $strictPlaceholderTypes
 					? (new IntegerType())->accepts($argumentType, true)->yes()
-					: ! $argumentType->toInteger() instanceof ErrorType;
+					: ! $argumentType->toInteger()->isError()->yes();
 			case 'float':
 				return $strictPlaceholderTypes
 					? TypeCombinator::union(
@@ -43,7 +42,7 @@ public function doesArgumentTypeMatchPlaceholder(Type $argumentType, bool $stric
 						// numeric-string is allowed for consistency with phpstan-strict-rules.
 						new IntersectionType([new StringType(), new AccessoryNumericStringType()]),
 					)->accepts($argumentType, true)->yes()
-					: ! $argumentType->toFloat() instanceof ErrorType;
+					: ! $argumentType->toFloat()->isError()->yes();
 			case 'string':
 			case 'mixed':
 				// The function signature already limits the parameters to stringable types, so there's
diff --git a/src/Rules/Functions/SortParameterCastableToStringRule.php b/src/Rules/Functions/SortParameterCastableToStringRule.php
index 1625024bd6..80cd21e178 100644
--- a/src/Rules/Functions/SortParameterCastableToStringRule.php
+++ b/src/Rules/Functions/SortParameterCastableToStringRule.php
@@ -12,7 +12,6 @@
 use PHPStan\Rules\ParameterCastableToStringCheck;
 use PHPStan\Rules\Rule;
 use PHPStan\Type\Constant\ConstantIntegerType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeUtils;
 use function array_key_exists;
@@ -112,7 +111,7 @@ public function processNode(Node $node, Scope $scope): array
 			$castFn = static function (Type $t): Type {
 				$float = $t->toFloat();
 
-				return $float instanceof ErrorType
+				return $float->isError()->yes()
 					? $float
 					: $t->toString();
 			};
diff --git a/src/Rules/Generators/YieldFromTypeRule.php b/src/Rules/Generators/YieldFromTypeRule.php
index b77f04b53a..bfd6cedf23 100644
--- a/src/Rules/Generators/YieldFromTypeRule.php
+++ b/src/Rules/Generators/YieldFromTypeRule.php
@@ -11,7 +11,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -118,7 +117,7 @@ public function processNode(Node $node, Scope $scope): array
 		$currentReturnType = $scopeFunction->getReturnType();
 		$exprSendType = $exprType->getTemplateType(Generator::class, 'TSend');
 		$thisSendType = $currentReturnType->getTemplateType(Generator::class, 'TSend');
-		if ($exprSendType instanceof ErrorType || $thisSendType instanceof ErrorType) {
+		if ($exprSendType->isError()->yes() || $thisSendType->isError()->yes()) {
 			return $messages;
 		}
 
diff --git a/src/Rules/Methods/CallToMethodStatementWithNoDiscardRule.php b/src/Rules/Methods/CallToMethodStatementWithNoDiscardRule.php
index 53755ee620..bbc773d566 100644
--- a/src/Rules/Methods/CallToMethodStatementWithNoDiscardRule.php
+++ b/src/Rules/Methods/CallToMethodStatementWithNoDiscardRule.php
@@ -10,7 +10,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use function sprintf;
 
@@ -80,7 +79,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $type): bool => $type->canCallMethods()->yes() && $type->hasMethod($methodName)->yes(),
 		);
 		$calledOnType = $typeResult->getType();
-		if ($calledOnType instanceof ErrorType) {
+		if ($calledOnType->isError()->yes()) {
 			return [];
 		}
 		if (!$calledOnType->canCallMethods()->yes()) {
diff --git a/src/Rules/Methods/CallToMethodStatementWithoutSideEffectsRule.php b/src/Rules/Methods/CallToMethodStatementWithoutSideEffectsRule.php
index 3a064dc646..82c3c69d99 100644
--- a/src/Rules/Methods/CallToMethodStatementWithoutSideEffectsRule.php
+++ b/src/Rules/Methods/CallToMethodStatementWithoutSideEffectsRule.php
@@ -10,7 +10,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
 use function count;
@@ -56,7 +55,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $type): bool => $type->canCallMethods()->yes() && $type->hasMethod($methodName)->yes(),
 		);
 		$calledOnType = $typeResult->getType();
-		if ($calledOnType instanceof ErrorType) {
+		if ($calledOnType->isError()->yes()) {
 			return [];
 		}
 		if (!$calledOnType->canCallMethods()->yes()) {
diff --git a/src/Rules/Methods/CallToStaticMethodStatementWithNoDiscardRule.php b/src/Rules/Methods/CallToStaticMethodStatementWithNoDiscardRule.php
index a1fa42d31e..dd13b1b476 100644
--- a/src/Rules/Methods/CallToStaticMethodStatementWithNoDiscardRule.php
+++ b/src/Rules/Methods/CallToStaticMethodStatementWithNoDiscardRule.php
@@ -11,7 +11,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\Type;
 use function sprintf;
@@ -89,7 +88,7 @@ public function processNode(Node $node, Scope $scope): array
 				static fn (Type $type): bool => $type->canCallMethods()->yes() && $type->hasMethod($methodName)->yes(),
 			);
 			$calledOnType = $typeResult->getType();
-			if ($calledOnType instanceof ErrorType) {
+			if ($calledOnType->isError()->yes()) {
 				return [];
 			}
 		}
diff --git a/src/Rules/Methods/CallToStaticMethodStatementWithoutSideEffectsRule.php b/src/Rules/Methods/CallToStaticMethodStatementWithoutSideEffectsRule.php
index a6fde544ca..39c27a9c58 100644
--- a/src/Rules/Methods/CallToStaticMethodStatementWithoutSideEffectsRule.php
+++ b/src/Rules/Methods/CallToStaticMethodStatementWithoutSideEffectsRule.php
@@ -11,7 +11,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\Type;
@@ -68,7 +67,7 @@ public function processNode(Node $node, Scope $scope): array
 				static fn (Type $type): bool => $type->canCallMethods()->yes() && $type->hasMethod($methodName)->yes(),
 			);
 			$calledOnType = $typeResult->getType();
-			if ($calledOnType instanceof ErrorType) {
+			if ($calledOnType->isError()->yes()) {
 				return [];
 			}
 		}
diff --git a/src/Rules/Methods/MethodCallCheck.php b/src/Rules/Methods/MethodCallCheck.php
index 3be2032165..06fd38559f 100644
--- a/src/Rules/Methods/MethodCallCheck.php
+++ b/src/Rules/Methods/MethodCallCheck.php
@@ -16,7 +16,6 @@
 use PHPStan\Rules\IdentifierRuleError;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\StaticType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
@@ -57,7 +56,7 @@ public function check(
 		);
 
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return [$typeResult->getUnknownClassErrors(), null];
 		}
 
diff --git a/src/Rules/Methods/StaticMethodCallCheck.php b/src/Rules/Methods/StaticMethodCallCheck.php
index b0a6f057e5..31998d0289 100644
--- a/src/Rules/Methods/StaticMethodCallCheck.php
+++ b/src/Rules/Methods/StaticMethodCallCheck.php
@@ -23,7 +23,6 @@
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\TrinaryLogic;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Generic\GenericClassStringType;
 use PHPStan\Type\StaticType;
 use PHPStan\Type\StringType;
@@ -179,7 +178,7 @@ public function check(
 				static fn (Type $type): bool => $type->canCallMethods()->yes() && $type->hasMethod($methodName)->yes(),
 			);
 			$classType = $classTypeResult->getType();
-			if ($classType instanceof ErrorType) {
+			if ($classType->isError()->yes()) {
 				return [$classTypeResult->getUnknownClassErrors(), null];
 			}
 		}
diff --git a/src/Rules/Missing/MissingReturnRule.php b/src/Rules/Missing/MissingReturnRule.php
index 5bc9d3d40e..70b8f98a13 100644
--- a/src/Rules/Missing/MissingReturnRule.php
+++ b/src/Rules/Missing/MissingReturnRule.php
@@ -12,7 +12,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\ShouldNotHappenException;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Generic\TemplateMixedType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\NeverType;
@@ -84,7 +83,7 @@ public function processNode(Node $node, Scope $scope): array
 		if ($statementResult->hasYield()) {
 			if ($this->checkPhpDocMissingReturn) {
 				$generatorReturnType = $returnType->getTemplateType(Generator::class, 'TReturn');
-				if (!$generatorReturnType instanceof ErrorType) {
+				if (!$generatorReturnType->isError()->yes()) {
 					$returnType = $generatorReturnType;
 					if ($returnType->isVoid()->yes()) {
 						return [];
diff --git a/src/Rules/Operators/InvalidBinaryOperationRule.php b/src/Rules/Operators/InvalidBinaryOperationRule.php
index 374aa87bfc..2b648557de 100644
--- a/src/Rules/Operators/InvalidBinaryOperationRule.php
+++ b/src/Rules/Operators/InvalidBinaryOperationRule.php
@@ -12,7 +12,6 @@
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\TrinaryLogic;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -70,11 +69,11 @@ public function processNode(Node $node, Scope $scope): array
 		}
 
 		if ($node instanceof Node\Expr\AssignOp\Concat || $node instanceof Node\Expr\BinaryOp\Concat) {
-			$callback = static fn (Type $type): bool => !$type->toString() instanceof ErrorType;
+			$callback = static fn (Type $type): bool => !$type->toString()->isError()->yes();
 		} elseif ($node instanceof Node\Expr\AssignOp\Plus || $node instanceof Node\Expr\BinaryOp\Plus) {
-			$callback = static fn (Type $type): bool => !$type->toNumber() instanceof ErrorType || $type->isArray()->yes();
+			$callback = static fn (Type $type): bool => !$type->toNumber()->isError()->yes() || $type->isArray()->yes();
 		} else {
-			$callback = static fn (Type $type): bool => !$type->toNumber() instanceof ErrorType;
+			$callback = static fn (Type $type): bool => !$type->toNumber()->isError()->yes();
 		}
 
 		$leftType = $this->ruleLevelHelper->findTypeToCheck(
@@ -83,7 +82,7 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			$callback,
 		)->getType();
-		if ($leftType instanceof ErrorType) {
+		if ($leftType->isError()->yes()) {
 			return [];
 		}
 
@@ -93,7 +92,7 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			$callback,
 		)->getType();
-		if ($rightType instanceof ErrorType) {
+		if ($rightType->isError()->yes()) {
 			return [];
 		}
 
@@ -105,7 +104,7 @@ public function processNode(Node $node, Scope $scope): array
 			->assignVariable($leftName, $leftType, $leftType, TrinaryLogic::createYes())
 			->assignVariable($rightName, $rightType, $rightType, TrinaryLogic::createYes());
 
-		if (!$scope->getType($newNode) instanceof ErrorType) {
+		if (!$scope->getType($newNode)->isError()->yes()) {
 			return [];
 		}
 
diff --git a/src/Rules/Operators/InvalidComparisonOperationRule.php b/src/Rules/Operators/InvalidComparisonOperationRule.php
index b410ae0fb9..b8ff469b5a 100644
--- a/src/Rules/Operators/InvalidComparisonOperationRule.php
+++ b/src/Rules/Operators/InvalidComparisonOperationRule.php
@@ -13,7 +13,6 @@
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\ArrayType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\FloatType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\MixedType;
@@ -73,7 +72,7 @@ public function processNode(Node $node, Scope $scope): array
 		);
 
 		if ($result !== null) {
-			if (! $result instanceof ErrorType) {
+			if (! $result->isError()->yes()) {
 				return [];
 			}
 
@@ -104,7 +103,7 @@ private function isNumberType(Scope $scope, Node\Expr $expr): bool
 		$type = $this->ruleLevelHelper->findTypeToCheck($scope, $expr, '', $onlyNumber)->getType();
 
 		if (
-			$type instanceof ErrorType
+			$type->isError()->yes()
 			|| !$type->equals($scope->getType($expr))
 		) {
 			return false;
diff --git a/src/Rules/Operators/InvalidIncDecOperationRule.php b/src/Rules/Operators/InvalidIncDecOperationRule.php
index 44ea25b7e0..e0a7dce865 100644
--- a/src/Rules/Operators/InvalidIncDecOperationRule.php
+++ b/src/Rules/Operators/InvalidIncDecOperationRule.php
@@ -12,7 +12,6 @@
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\Accessory\AccessoryNumericStringType;
 use PHPStan\Type\BooleanType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\FloatType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\IntersectionType;
@@ -141,7 +140,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $type): bool => $allowedTypes->isSuperTypeOf($type)->yes(),
 		)->getType();
 
-		if ($varType instanceof ErrorType || $allowedTypes->isSuperTypeOf($varType)->yes()) {
+		if ($varType->isError()->yes() || $allowedTypes->isSuperTypeOf($varType)->yes()) {
 			return [];
 		}
 
diff --git a/src/Rules/Operators/InvalidUnaryOperationRule.php b/src/Rules/Operators/InvalidUnaryOperationRule.php
index 1b688dc06d..410a92f0b1 100644
--- a/src/Rules/Operators/InvalidUnaryOperationRule.php
+++ b/src/Rules/Operators/InvalidUnaryOperationRule.php
@@ -11,7 +11,6 @@
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\TrinaryLogic;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -53,7 +52,7 @@ public function processNode(Node $node, Scope $scope): array
 		if ($node instanceof Node\Expr\BitwiseNot) {
 			$callback = static fn (Type $type): bool => $type->isString()->yes() || $type->isInteger()->yes() || $type->isFloat()->yes();
 		} else {
-			$callback = static fn (Type $type): bool => !$type->toNumber() instanceof ErrorType;
+			$callback = static fn (Type $type): bool => !$type->toNumber()->isError()->yes();
 		}
 
 		$exprType = $this->ruleLevelHelper->findTypeToCheck(
@@ -62,7 +61,7 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			$callback,
 		)->getType();
-		if ($exprType instanceof ErrorType) {
+		if ($exprType->isError()->yes()) {
 			return [];
 		}
 
@@ -71,7 +70,7 @@ public function processNode(Node $node, Scope $scope): array
 		}
 
 		$scope = $scope->assignVariable($varName, $exprType, $exprType, TrinaryLogic::createYes());
-		if (!$scope->getType($newNode) instanceof ErrorType) {
+		if (!$scope->getType($newNode)->isError()->yes()) {
 			return [];
 		}
 
diff --git a/src/Rules/Operators/PipeOperatorRule.php b/src/Rules/Operators/PipeOperatorRule.php
index 07cfedeb7e..070a96184f 100644
--- a/src/Rules/Operators/PipeOperatorRule.php
+++ b/src/Rules/Operators/PipeOperatorRule.php
@@ -8,7 +8,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use function sprintf;
 
@@ -36,7 +35,7 @@ public function processNode(Node $node, Scope $scope): array
 			'',
 			static fn (Type $type) => $type->isCallable()->yes(),
 		)->getType();
-		if ($rightType instanceof ErrorType) {
+		if ($rightType->isError()->yes()) {
 			return [];
 		}
 		if (!$rightType->isCallable()->yes()) {
diff --git a/src/Rules/ParameterCastableToStringCheck.php b/src/Rules/ParameterCastableToStringCheck.php
index 244cd1ba4f..15cddf88c2 100644
--- a/src/Rules/ParameterCastableToStringCheck.php
+++ b/src/Rules/ParameterCastableToStringCheck.php
@@ -7,7 +7,6 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Reflection\ParameterReflection;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function sprintf;
@@ -38,12 +37,12 @@ public function checkParameter(
 			$scope,
 			$parameter->value,
 			'',
-			static fn (Type $type): bool => $type->isArray()->yes() && !$castFn($type->getIterableValueType()) instanceof ErrorType,
+			static fn (Type $type): bool => $type->isArray()->yes() && !$castFn($type->getIterableValueType())->isError()->yes(),
 		);
 
 		if (
 			! $typeResult->getType()->isArray()->yes()
-			|| !$castFn($typeResult->getType()->getIterableValueType()) instanceof ErrorType
+			|| !$castFn($typeResult->getType()->getIterableValueType())->isError()->yes()
 		) {
 			return null;
 		}
diff --git a/src/Rules/PhpDoc/AssertRuleHelper.php b/src/Rules/PhpDoc/AssertRuleHelper.php
index 0dc14b638a..7bf91a7645 100644
--- a/src/Rules/PhpDoc/AssertRuleHelper.php
+++ b/src/Rules/PhpDoc/AssertRuleHelper.php
@@ -20,7 +20,6 @@
 use PHPStan\Rules\IdentifierRuleError;
 use PHPStan\Rules\MissingTypehintCheck;
 use PHPStan\Rules\RuleErrorBuilder;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\VerbosityLevel;
 use function array_key_exists;
@@ -83,7 +82,7 @@ public function check(
 			$assertedExpr = $assert->getParameter()->getExpr(new TypeExpr($parametersByName[$parameterName]));
 			$assertedExprType = $scope->getType($assertedExpr);
 			$assertedExprString = $assert->getParameter()->describe();
-			if ($assertedExprType instanceof ErrorType) {
+			if ($assertedExprType->isError()->yes()) {
 				$errors[] = RuleErrorBuilder::message(sprintf('Assert references unknown %s.', $assertedExprString))
 					->identifier('assert.unknownExpr')
 					->build();
diff --git a/src/Rules/PhpDoc/UnresolvableTypeHelper.php b/src/Rules/PhpDoc/UnresolvableTypeHelper.php
index 69f539f373..39f66e63cc 100644
--- a/src/Rules/PhpDoc/UnresolvableTypeHelper.php
+++ b/src/Rules/PhpDoc/UnresolvableTypeHelper.php
@@ -3,7 +3,6 @@
 namespace PHPStan\Rules\PhpDoc;
 
 use PHPStan\DependencyInjection\AutowiredService;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeTraverser;
@@ -16,7 +15,7 @@ public function containsUnresolvableType(Type $type): bool
 	{
 		$containsUnresolvable = false;
 		TypeTraverser::map($type, static function (Type $type, callable $traverse) use (&$containsUnresolvable): Type {
-			if ($type instanceof ErrorType) {
+			if ($type->isError()->yes()) {
 				$containsUnresolvable = true;
 				return $type;
 			}
diff --git a/src/Rules/Properties/AccessPropertiesCheck.php b/src/Rules/Properties/AccessPropertiesCheck.php
index 82d1753a1d..9932a9b32e 100644
--- a/src/Rules/Properties/AccessPropertiesCheck.php
+++ b/src/Rules/Properties/AccessPropertiesCheck.php
@@ -21,7 +21,6 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\Type\Constant\ConstantStringType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\StaticType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
@@ -66,13 +65,13 @@ public function check(PropertyFetch $node, Scope $scope, bool $write): array
 					$scope,
 					$node->name,
 					'',
-					static fn (Type $type) => !$type->toString() instanceof ErrorType && $type->toString()->isString()->yes(),
+					static fn (Type $type) => !$type->toString()->isError()->yes() && $type->toString()->isString()->yes(),
 				);
 				$nameType = $nameTypeResult->getType();
 				if (
-					!$nameType instanceof ErrorType
+					!$nameType->isError()->yes()
 					&& (
-						$nameType->toString() instanceof ErrorType
+						$nameType->toString()->isError()->yes()
 						|| !$nameType->toString()->isString()->yes()
 					)
 				) {
@@ -106,7 +105,7 @@ private function processSingleProperty(Scope $scope, PropertyFetch $node, string
 			),
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 
diff --git a/src/Rules/Properties/AccessStaticPropertiesCheck.php b/src/Rules/Properties/AccessStaticPropertiesCheck.php
index 487453f428..9dbc6383c7 100644
--- a/src/Rules/Properties/AccessStaticPropertiesCheck.php
+++ b/src/Rules/Properties/AccessStaticPropertiesCheck.php
@@ -19,7 +19,6 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
 use PHPStan\Type\Constant\ConstantStringType;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\StringType;
 use PHPStan\Type\ThisType;
 use PHPStan\Type\Type;
@@ -154,7 +153,7 @@ private function processSingleProperty(Scope $scope, StaticPropertyFetch $node,
 				static fn (Type $type): bool => $type->canAccessProperties()->yes() && $type->hasStaticProperty($name)->yes(),
 			);
 			$classType = $classTypeResult->getType();
-			if ($classType instanceof ErrorType) {
+			if ($classType->isError()->yes()) {
 				return $classTypeResult->getUnknownClassErrors();
 			}
 		}
diff --git a/src/Rules/RestrictedUsage/RestrictedClassConstantUsageRule.php b/src/Rules/RestrictedUsage/RestrictedClassConstantUsageRule.php
index 8f8ad16229..074a37c0ff 100644
--- a/src/Rules/RestrictedUsage/RestrictedClassConstantUsageRule.php
+++ b/src/Rules/RestrictedUsage/RestrictedClassConstantUsageRule.php
@@ -12,7 +12,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 
 /**
@@ -63,7 +62,7 @@ public function processNode(Node $node, Scope $scope): array
 				static fn (Type $type): bool => $type->canAccessConstants()->yes() && $type->hasConstant($constantName)->yes(),
 			);
 
-			if ($classTypeResult->getType() instanceof ErrorType) {
+			if ($classTypeResult->getType()->isError()->yes()) {
 				return [];
 			}
 
diff --git a/src/Rules/RestrictedUsage/RestrictedStaticMethodCallableUsageRule.php b/src/Rules/RestrictedUsage/RestrictedStaticMethodCallableUsageRule.php
index 22230ca299..d2408afdfb 100644
--- a/src/Rules/RestrictedUsage/RestrictedStaticMethodCallableUsageRule.php
+++ b/src/Rules/RestrictedUsage/RestrictedStaticMethodCallableUsageRule.php
@@ -13,7 +13,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 
 /**
@@ -64,7 +63,7 @@ public function processNode(Node $node, Scope $scope): array
 				static fn (Type $type): bool => $type->canCallMethods()->yes() && $type->hasMethod($methodName)->yes(),
 			);
 
-			if ($classTypeResult->getType() instanceof ErrorType) {
+			if ($classTypeResult->getType()->isError()->yes()) {
 				return [];
 			}
 
diff --git a/src/Rules/RestrictedUsage/RestrictedStaticMethodUsageRule.php b/src/Rules/RestrictedUsage/RestrictedStaticMethodUsageRule.php
index 898075b514..2b1e26d62c 100644
--- a/src/Rules/RestrictedUsage/RestrictedStaticMethodUsageRule.php
+++ b/src/Rules/RestrictedUsage/RestrictedStaticMethodUsageRule.php
@@ -12,7 +12,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 
 /**
@@ -63,7 +62,7 @@ public function processNode(Node $node, Scope $scope): array
 				static fn (Type $type): bool => $type->canCallMethods()->yes() && $type->hasMethod($methodName)->yes(),
 			);
 
-			if ($classTypeResult->getType() instanceof ErrorType) {
+			if ($classTypeResult->getType()->isError()->yes()) {
 				return [];
 			}
 
diff --git a/src/Rules/RestrictedUsage/RestrictedStaticPropertyUsageRule.php b/src/Rules/RestrictedUsage/RestrictedStaticPropertyUsageRule.php
index 6361276a20..97b55881e7 100644
--- a/src/Rules/RestrictedUsage/RestrictedStaticPropertyUsageRule.php
+++ b/src/Rules/RestrictedUsage/RestrictedStaticPropertyUsageRule.php
@@ -12,7 +12,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 
 /**
@@ -63,7 +62,7 @@ public function processNode(Node $node, Scope $scope): array
 				static fn (Type $type): bool => $type->canAccessProperties()->yes() && $type->hasInstanceProperty($propertyName)->yes(),
 			);
 
-			if ($classTypeResult->getType() instanceof ErrorType) {
+			if ($classTypeResult->getType()->isError()->yes()) {
 				return [];
 			}
 
diff --git a/src/Rules/Variables/ParameterOutAssignedTypeRule.php b/src/Rules/Variables/ParameterOutAssignedTypeRule.php
index 5bc0118057..3bb844552a 100644
--- a/src/Rules/Variables/ParameterOutAssignedTypeRule.php
+++ b/src/Rules/Variables/ParameterOutAssignedTypeRule.php
@@ -10,7 +10,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeUtils;
 use PHPStan\Type\VerbosityLevel;
@@ -85,7 +84,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $type): bool => $outType->isSuperTypeOf($type)->yes(),
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 
diff --git a/src/Rules/Variables/ParameterOutExecutionEndTypeRule.php b/src/Rules/Variables/ParameterOutExecutionEndTypeRule.php
index edddff8a91..fb34626f7d 100644
--- a/src/Rules/Variables/ParameterOutExecutionEndTypeRule.php
+++ b/src/Rules/Variables/ParameterOutExecutionEndTypeRule.php
@@ -14,7 +14,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeUtils;
@@ -102,7 +101,7 @@ private function processSingleParameter(
 			static fn (Type $type): bool => $outType->isSuperTypeOf($type)->yes(),
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 
diff --git a/src/Rules/Variables/VariableCloningRule.php b/src/Rules/Variables/VariableCloningRule.php
index bab0f8d995..f1e6d49c02 100644
--- a/src/Rules/Variables/VariableCloningRule.php
+++ b/src/Rules/Variables/VariableCloningRule.php
@@ -10,7 +10,6 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Rules\RuleLevelHelper;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function is_string;
@@ -41,7 +40,7 @@ public function processNode(Node $node, Scope $scope): array
 			static fn (Type $type): bool => $type->isCloneable()->yes(),
 		);
 		$type = $typeResult->getType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return $typeResult->getUnknownClassErrors();
 		}
 		if ($type->isCloneable()->yes()) {
diff --git a/src/Type/Accessory/AccessoryArrayListType.php b/src/Type/Accessory/AccessoryArrayListType.php
index 6ed6baeced..4dd44f5dcc 100644
--- a/src/Type/Accessory/AccessoryArrayListType.php
+++ b/src/Type/Accessory/AccessoryArrayListType.php
@@ -424,6 +424,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/Accessory/AccessoryLiteralStringType.php b/src/Type/Accessory/AccessoryLiteralStringType.php
index d8a02005d6..d9e9631bfc 100644
--- a/src/Type/Accessory/AccessoryLiteralStringType.php
+++ b/src/Type/Accessory/AccessoryLiteralStringType.php
@@ -147,7 +147,7 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $uni
 	{
 		$stringOffset = (new StringType())->setOffsetValueType($offsetType, $valueType, $unionValues);
 
-		if ($stringOffset instanceof ErrorType) {
+		if ($stringOffset->isError()->yes()) {
 			return $stringOffset;
 		}
 
@@ -332,6 +332,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createYes();
diff --git a/src/Type/Accessory/AccessoryLowercaseStringType.php b/src/Type/Accessory/AccessoryLowercaseStringType.php
index 3e1383bdb4..fde23aef39 100644
--- a/src/Type/Accessory/AccessoryLowercaseStringType.php
+++ b/src/Type/Accessory/AccessoryLowercaseStringType.php
@@ -144,7 +144,7 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $uni
 	{
 		$stringOffset = (new StringType())->setOffsetValueType($offsetType, $valueType, $unionValues);
 
-		if ($stringOffset instanceof ErrorType) {
+		if ($stringOffset->isError()->yes()) {
 			return $stringOffset;
 		}
 
@@ -329,6 +329,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createYes();
diff --git a/src/Type/Accessory/AccessoryNonEmptyStringType.php b/src/Type/Accessory/AccessoryNonEmptyStringType.php
index a8b573809a..36f1f9081e 100644
--- a/src/Type/Accessory/AccessoryNonEmptyStringType.php
+++ b/src/Type/Accessory/AccessoryNonEmptyStringType.php
@@ -156,7 +156,7 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $uni
 	{
 		$stringOffset = (new StringType())->setOffsetValueType($offsetType, $valueType, $unionValues);
 
-		if ($stringOffset instanceof ErrorType) {
+		if ($stringOffset->isError()->yes()) {
 			return $stringOffset;
 		}
 
@@ -327,6 +327,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createYes();
diff --git a/src/Type/Accessory/AccessoryNonFalsyStringType.php b/src/Type/Accessory/AccessoryNonFalsyStringType.php
index f32d613154..2ae0e3a201 100644
--- a/src/Type/Accessory/AccessoryNonFalsyStringType.php
+++ b/src/Type/Accessory/AccessoryNonFalsyStringType.php
@@ -151,7 +151,7 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $uni
 	{
 		$stringOffset = (new StringType())->setOffsetValueType($offsetType, $valueType, $unionValues);
 
-		if ($stringOffset instanceof ErrorType) {
+		if ($stringOffset->isError()->yes()) {
 			return $stringOffset;
 		}
 
@@ -327,6 +327,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createYes();
diff --git a/src/Type/Accessory/AccessoryNumericStringType.php b/src/Type/Accessory/AccessoryNumericStringType.php
index c10dd28082..43f59ef061 100644
--- a/src/Type/Accessory/AccessoryNumericStringType.php
+++ b/src/Type/Accessory/AccessoryNumericStringType.php
@@ -152,7 +152,7 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $uni
 	{
 		$stringOffset = (new StringType())->setOffsetValueType($offsetType, $valueType, $unionValues);
 
-		if ($stringOffset instanceof ErrorType) {
+		if ($stringOffset->isError()->yes()) {
 			return $stringOffset;
 		}
 
@@ -332,6 +332,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createYes();
diff --git a/src/Type/Accessory/AccessoryUppercaseStringType.php b/src/Type/Accessory/AccessoryUppercaseStringType.php
index 5688e62df7..8dfcbff46f 100644
--- a/src/Type/Accessory/AccessoryUppercaseStringType.php
+++ b/src/Type/Accessory/AccessoryUppercaseStringType.php
@@ -144,7 +144,7 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $uni
 	{
 		$stringOffset = (new StringType())->setOffsetValueType($offsetType, $valueType, $unionValues);
 
-		if ($stringOffset instanceof ErrorType) {
+		if ($stringOffset->isError()->yes()) {
 			return $stringOffset;
 		}
 
@@ -329,6 +329,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createYes();
diff --git a/src/Type/Accessory/HasOffsetType.php b/src/Type/Accessory/HasOffsetType.php
index da6c176655..8e42871379 100644
--- a/src/Type/Accessory/HasOffsetType.php
+++ b/src/Type/Accessory/HasOffsetType.php
@@ -342,6 +342,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createMaybe();
diff --git a/src/Type/Accessory/HasOffsetValueType.php b/src/Type/Accessory/HasOffsetValueType.php
index 5e7c834942..c1adf989ea 100644
--- a/src/Type/Accessory/HasOffsetValueType.php
+++ b/src/Type/Accessory/HasOffsetValueType.php
@@ -421,6 +421,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createMaybe();
diff --git a/src/Type/Accessory/NonEmptyArrayType.php b/src/Type/Accessory/NonEmptyArrayType.php
index a58f87cb86..ca42eaa3ce 100644
--- a/src/Type/Accessory/NonEmptyArrayType.php
+++ b/src/Type/Accessory/NonEmptyArrayType.php
@@ -410,6 +410,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/Accessory/OversizedArrayType.php b/src/Type/Accessory/OversizedArrayType.php
index 77fdec48fb..6904fc6806 100644
--- a/src/Type/Accessory/OversizedArrayType.php
+++ b/src/Type/Accessory/OversizedArrayType.php
@@ -394,6 +394,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/ArrayType.php b/src/Type/ArrayType.php
index f97ac2a014..2426cc0931 100644
--- a/src/Type/ArrayType.php
+++ b/src/Type/ArrayType.php
@@ -269,7 +269,7 @@ public function looseCompare(Type $type, PhpVersion $phpVersion): BooleanType
 	public function hasOffsetValueType(Type $offsetType): TrinaryLogic
 	{
 		$offsetArrayKeyType = $offsetType->toArrayKey();
-		if ($offsetArrayKeyType instanceof ErrorType) {
+		if ($offsetArrayKeyType->isError()->yes()) {
 			$allowedArrayKeys = AllowedArrayKeysTypes::getType();
 			$offsetArrayKeyType = TypeCombinator::intersect($allowedArrayKeys, $offsetType)->toArrayKey();
 			if ($offsetArrayKeyType instanceof NeverType) {
@@ -297,7 +297,7 @@ public function getOffsetValueType(Type $offsetType): Type
 		}
 
 		$type = $this->getItemType();
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			return new MixedType();
 		}
 
@@ -440,7 +440,7 @@ public function fillKeysArray(Type $valueType): Type
 		$itemType = $this->getItemType();
 		if ($itemType->isInteger()->no()) {
 			$stringKeyType = $itemType->toString();
-			if ($stringKeyType instanceof ErrorType) {
+			if ($stringKeyType->isError()->yes()) {
 				return $stringKeyType;
 			}
 
diff --git a/src/Type/BenevolentUnionType.php b/src/Type/BenevolentUnionType.php
index e6d826abdc..c28b91d2b6 100644
--- a/src/Type/BenevolentUnionType.php
+++ b/src/Type/BenevolentUnionType.php
@@ -39,7 +39,7 @@ protected function unionTypes(callable $getType): Type
 		$resultTypes = [];
 		foreach ($this->getTypes() as $type) {
 			$result = $getType($type);
-			if ($result instanceof ErrorType) {
+			if ($result->isError()->yes()) {
 				continue;
 			}
 
@@ -78,7 +78,7 @@ public function getOffsetValueType(Type $offsetType): Type
 		$types = [];
 		foreach ($this->getTypes() as $innerType) {
 			$valueType = $innerType->getOffsetValueType($offsetType);
-			if ($valueType instanceof ErrorType) {
+			if ($valueType->isError()->yes()) {
 				continue;
 			}
 
diff --git a/src/Type/CallableType.php b/src/Type/CallableType.php
index 079afc8c1e..c7cf4ec3e9 100644
--- a/src/Type/CallableType.php
+++ b/src/Type/CallableType.php
@@ -624,6 +624,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return new ObjectWithoutClassType();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/ClosureType.php b/src/Type/ClosureType.php
index 49bbfe8c1b..8ec126ce7a 100644
--- a/src/Type/ClosureType.php
+++ b/src/Type/ClosureType.php
@@ -796,6 +796,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return $this;
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/Constant/ConstantArrayType.php b/src/Type/Constant/ConstantArrayType.php
index 4cec2bf409..f68f543ba3 100644
--- a/src/Type/Constant/ConstantArrayType.php
+++ b/src/Type/Constant/ConstantArrayType.php
@@ -583,7 +583,7 @@ public function findTypeAndMethodNames(): array
 	public function hasOffsetValueType(Type $offsetType): TrinaryLogic
 	{
 		$offsetArrayKeyType = $offsetType->toArrayKey();
-		if ($offsetArrayKeyType instanceof ErrorType) {
+		if ($offsetArrayKeyType->isError()->yes()) {
 			$allowedArrayKeys = AllowedArrayKeysTypes::getType();
 			$offsetArrayKeyType = TypeCombinator::intersect($allowedArrayKeys, $offsetType)->toArrayKey();
 			if ($offsetArrayKeyType instanceof NeverType) {
@@ -677,7 +677,7 @@ public function getOffsetValueType(Type $offsetType): Type
 
 		if (count($matchingValueTypes) > 0) {
 			$type = TypeCombinator::union(...$matchingValueTypes);
-			if ($type instanceof ErrorType) {
+			if ($type->isError()->yes()) {
 				return new MixedType();
 			}
 
@@ -818,7 +818,7 @@ public function fillKeysArray(Type $valueType): Type
 		foreach ($this->valueTypes as $i => $keyType) {
 			if ($keyType->isInteger()->no()) {
 				$stringKeyType = $keyType->toString();
-				if ($stringKeyType instanceof ErrorType) {
+				if ($stringKeyType->isError()->yes()) {
 					return $stringKeyType;
 				}
 
diff --git a/src/Type/Constant/ConstantStringType.php b/src/Type/Constant/ConstantStringType.php
index e4c34e609f..55a05d6a26 100644
--- a/src/Type/Constant/ConstantStringType.php
+++ b/src/Type/Constant/ConstantStringType.php
@@ -399,7 +399,7 @@ public function getOffsetValueType(Type $offsetType): Type
 	public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $unionValues = true): Type
 	{
 		$valueStringType = $valueType->toString();
-		if ($valueStringType instanceof ErrorType) {
+		if ($valueStringType->isError()->yes()) {
 			return new ErrorType();
 		}
 		if (
diff --git a/src/Type/ErrorType.php b/src/Type/ErrorType.php
index 751271aef3..781bd7fe8a 100644
--- a/src/Type/ErrorType.php
+++ b/src/Type/ErrorType.php
@@ -2,6 +2,8 @@
 
 namespace PHPStan\Type;
 
+use PHPStan\TrinaryLogic;
+
 /** @api */
 class ErrorType extends MixedType
 {
@@ -36,6 +38,11 @@ public function subtract(Type $type): Type
 		return new self();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createYes();
+	}
+
 	public function equals(Type $type): bool
 	{
 		return $type instanceof self;
diff --git a/src/Type/FloatType.php b/src/Type/FloatType.php
index 92ebb92cf1..2987d7e4b6 100644
--- a/src/Type/FloatType.php
+++ b/src/Type/FloatType.php
@@ -266,6 +266,11 @@ public function isScalar(): TrinaryLogic
 		return TrinaryLogic::createYes();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function looseCompare(Type $type, PhpVersion $phpVersion): BooleanType
 	{
 		return new BooleanType();
diff --git a/src/Type/Generic/GenericObjectType.php b/src/Type/Generic/GenericObjectType.php
index 54bef86b29..a9450ceaa5 100644
--- a/src/Type/Generic/GenericObjectType.php
+++ b/src/Type/Generic/GenericObjectType.php
@@ -174,7 +174,7 @@ private function isSuperTypeOfInternal(Type $type, bool $acceptsContext): IsSupe
 			if (!isset($this->types[$i])) {
 				continue;
 			}
-			if ($templateType instanceof ErrorType) {
+			if ($templateType->isError()->yes()) {
 				continue;
 			}
 			if (!$templateType instanceof TemplateType) {
diff --git a/src/Type/Generic/TemplateTypeHelper.php b/src/Type/Generic/TemplateTypeHelper.php
index 29ecd48720..acfaeead3b 100644
--- a/src/Type/Generic/TemplateTypeHelper.php
+++ b/src/Type/Generic/TemplateTypeHelper.php
@@ -3,7 +3,6 @@
 namespace PHPStan\Type\Generic;
 
 use PHPStan\Reflection\ParametersAcceptor;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\GeneralizePrecision;
 use PHPStan\Type\NonAcceptingNeverType;
 use PHPStan\Type\Type;
@@ -44,7 +43,7 @@ public static function resolveTemplateTypes(
 					return $traverse($type);
 				}
 
-				if ($newType instanceof ErrorType && !$keepErrorTypes) {
+				if ($newType->isError()->yes() && !$keepErrorTypes) {
 					return $traverse($type->getDefault() ?? $type->getBound());
 				}
 
diff --git a/src/Type/Generic/TemplateTypeTrait.php b/src/Type/Generic/TemplateTypeTrait.php
index 584439c12d..4fe6b147c9 100644
--- a/src/Type/Generic/TemplateTypeTrait.php
+++ b/src/Type/Generic/TemplateTypeTrait.php
@@ -6,7 +6,6 @@
 use PHPStan\PhpDocParser\Ast\Type\TypeNode;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\AcceptsResult;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\IntersectionType;
 use PHPStan\Type\IsSuperTypeOfResult;
 use PHPStan\Type\MixedType;
@@ -18,6 +17,7 @@
 use PHPStan\Type\TypeUtils;
 use PHPStan\Type\UnionType;
 use PHPStan\Type\VerbosityLevel;
+use function is_string;
 use function sprintf;
 
 /**
@@ -74,7 +74,7 @@ public function describe(VerbosityLevel $level): string
 			$defaultDescription = '';
 			if ($this->default !== null) {
 				$recursionGuard = RecursionGuard::runOnObjectIdentity($this->default, fn () => $this->default->describe($level));
-				if (!$recursionGuard instanceof ErrorType) {
+				if (is_string($recursionGuard)) {
 					$defaultDescription .= sprintf(' = %s', $recursionGuard);
 				}
 			}
diff --git a/src/Type/IntersectionType.php b/src/Type/IntersectionType.php
index 16cb33d2dd..a95802f21f 100644
--- a/src/Type/IntersectionType.php
+++ b/src/Type/IntersectionType.php
@@ -786,6 +786,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return $this->intersectTypes(static fn (Type $type): Type => $type->getObjectTypeOrClassStringObjectType());
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return $this->intersectResults(static fn (Type $type): TrinaryLogic => $type->isError());
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return $this->intersectResults(static fn (Type $type): TrinaryLogic => $type->isVoid());
diff --git a/src/Type/IterableType.php b/src/Type/IterableType.php
index c2b44b809b..5238a24e1a 100644
--- a/src/Type/IterableType.php
+++ b/src/Type/IterableType.php
@@ -406,6 +406,11 @@ public function isVoid(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isScalar(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/JustNullableTypeTrait.php b/src/Type/JustNullableTypeTrait.php
index 5435c540ff..85319aa71a 100644
--- a/src/Type/JustNullableTypeTrait.php
+++ b/src/Type/JustNullableTypeTrait.php
@@ -164,6 +164,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return new ErrorType();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/MixedType.php b/src/Type/MixedType.php
index ad8d4fbfb1..71b8ca942f 100644
--- a/src/Type/MixedType.php
+++ b/src/Type/MixedType.php
@@ -1065,6 +1065,17 @@ public function isScalar(): TrinaryLogic
 		return TrinaryLogic::createMaybe();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		if ($this->subtractedType !== null) {
+			if ($this->subtractedType->isSuperTypeOf(new ErrorType())->yes()) {
+				return TrinaryLogic::createNo();
+			}
+		}
+
+		return TrinaryLogic::createMaybe();
+	}
+
 	public function looseCompare(Type $type, PhpVersion $phpVersion): BooleanType
 	{
 		return new BooleanType();
diff --git a/src/Type/NeverType.php b/src/Type/NeverType.php
index 5fc9a05280..d7d310c366 100644
--- a/src/Type/NeverType.php
+++ b/src/Type/NeverType.php
@@ -548,6 +548,11 @@ public function isScalar(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function looseCompare(Type $type, PhpVersion $phpVersion): BooleanType
 	{
 		return new BooleanType();
diff --git a/src/Type/NullType.php b/src/Type/NullType.php
index ef2408e713..f162347069 100644
--- a/src/Type/NullType.php
+++ b/src/Type/NullType.php
@@ -335,6 +335,11 @@ public function isScalar(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function looseCompare(Type $type, PhpVersion $phpVersion): BooleanType
 	{
 		if ($type instanceof ConstantScalarType) {
diff --git a/src/Type/ObjectType.php b/src/Type/ObjectType.php
index 3b7a72baaa..5572d76038 100644
--- a/src/Type/ObjectType.php
+++ b/src/Type/ObjectType.php
@@ -156,7 +156,7 @@ public function hasProperty(string $propertyName): TrinaryLogic
 		}
 
 		$classHasProperty = RecursionGuard::run($this, static fn (): bool => $classReflection->hasProperty($propertyName));
-		if ($classHasProperty === true || $classHasProperty instanceof ErrorType) {
+		if ($classHasProperty !== false) {
 			return TrinaryLogic::createYes();
 		}
 
@@ -262,7 +262,7 @@ public function hasInstanceProperty(string $propertyName): TrinaryLogic
 		}
 
 		$classHasProperty = RecursionGuard::run($this, static fn (): bool => $classReflection->hasInstanceProperty($propertyName));
-		if ($classHasProperty === true || $classHasProperty instanceof ErrorType) {
+		if ($classHasProperty !== false) {
 			return TrinaryLogic::createYes();
 		}
 
@@ -368,7 +368,7 @@ public function hasStaticProperty(string $propertyName): TrinaryLogic
 		}
 
 		$classHasProperty = RecursionGuard::run($this, static fn (): bool => $classReflection->hasStaticProperty($propertyName));
-		if ($classHasProperty === true || $classHasProperty instanceof ErrorType) {
+		if ($classHasProperty !== false) {
 			return TrinaryLogic::createYes();
 		}
 
@@ -1076,7 +1076,7 @@ public function getTemplateType(string $ancestorClassName, string $templateTypeN
 		if ($type === null) {
 			return new ErrorType();
 		}
-		if ($type instanceof ErrorType) {
+		if ($type->isError()->yes()) {
 			$templateTypeMap = $ancestorClassReflection->getTemplateTypeMap();
 			$templateType = $templateTypeMap->getType($templateTypeName);
 			if ($templateType === null) {
@@ -1138,7 +1138,7 @@ public function getIterableKeyType(): Type
 		if (!$extraOffsetAccessible && $this->isInstanceOf(Traversable::class)->yes()) {
 			$isTraversable = true;
 			$tKey = $this->getTemplateType(Traversable::class, 'TKey');
-			if (!$tKey instanceof ErrorType) {
+			if (!$tKey->isError()->yes()) {
 				if (!$tKey instanceof MixedType || $tKey->isExplicitMixed()) {
 					return $tKey;
 				}
@@ -1185,7 +1185,7 @@ public function getIterableValueType(): Type
 		if (!$extraOffsetAccessible && $this->isInstanceOf(Traversable::class)->yes()) {
 			$isTraversable = true;
 			$tValue = $this->getTemplateType(Traversable::class, 'TValue');
-			if (!$tValue instanceof ErrorType) {
+			if (!$tValue->isError()->yes()) {
 				if (!$tValue instanceof MixedType || $tValue->isExplicitMixed()) {
 					return $tValue;
 				}
@@ -1317,6 +1317,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return $this;
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/Php/AbsFunctionDynamicReturnTypeExtension.php b/src/Type/Php/AbsFunctionDynamicReturnTypeExtension.php
index 7de2eebbd7..5a1c7ebd32 100644
--- a/src/Type/Php/AbsFunctionDynamicReturnTypeExtension.php
+++ b/src/Type/Php/AbsFunctionDynamicReturnTypeExtension.php
@@ -7,7 +7,6 @@
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\Type;
 
 #[AutowiredService]
@@ -35,7 +34,7 @@ public function getTypeFromFunctionCall(
 
 		$outputType = $inputType->toAbsoluteNumber();
 
-		if ($outputType instanceof ErrorType) {
+		if ($outputType->isError()->yes()) {
 			return null;
 		}
 
diff --git a/src/Type/Php/ArrayCombineFunctionReturnTypeExtension.php b/src/Type/Php/ArrayCombineFunctionReturnTypeExtension.php
index a9b9c0e042..6e63747a79 100644
--- a/src/Type/Php/ArrayCombineFunctionReturnTypeExtension.php
+++ b/src/Type/Php/ArrayCombineFunctionReturnTypeExtension.php
@@ -14,7 +14,6 @@
 use PHPStan\Type\Constant\ConstantBooleanType;
 use PHPStan\Type\ConstantScalarType;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
@@ -98,7 +97,7 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 			$itemType = $keysParamType->getIterableValueType();
 
 			if ($itemType->isInteger()->no()) {
-				if ($itemType->toString() instanceof ErrorType) {
+				if ($itemType->toString()->isError()->yes()) {
 					return new NeverType();
 				}
 
@@ -140,7 +139,7 @@ private function sanitizeConstantArrayKeyTypes(array $types): ?array
 		$sanitizedTypes = [];
 
 		foreach ($types as $type) {
-			if ($type->isInteger()->no() && ! $type->toString() instanceof ErrorType) {
+			if ($type->isInteger()->no() && ! $type->toString()->isError()->yes()) {
 				$type = $type->toString();
 			}
 
diff --git a/src/Type/Php/IteratorToArrayFunctionReturnTypeExtension.php b/src/Type/Php/IteratorToArrayFunctionReturnTypeExtension.php
index b4ed3b2d18..d0d43d65dd 100644
--- a/src/Type/Php/IteratorToArrayFunctionReturnTypeExtension.php
+++ b/src/Type/Php/IteratorToArrayFunctionReturnTypeExtension.php
@@ -9,7 +9,6 @@
 use PHPStan\Type\Accessory\AccessoryArrayListType;
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
@@ -48,7 +47,7 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 
 		$arrayKeyType = $traversableType->getIterableKeyType()->toArrayKey();
 
-		if ($arrayKeyType instanceof ErrorType) {
+		if ($arrayKeyType->isError()->yes()) {
 			return new NeverType(true);
 		}
 
diff --git a/src/Type/Php/StrvalFamilyFunctionReturnTypeExtension.php b/src/Type/Php/StrvalFamilyFunctionReturnTypeExtension.php
index 3fa0403bab..24647a25ec 100644
--- a/src/Type/Php/StrvalFamilyFunctionReturnTypeExtension.php
+++ b/src/Type/Php/StrvalFamilyFunctionReturnTypeExtension.php
@@ -8,7 +8,6 @@
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
-use PHPStan\Type\ErrorType;
 use PHPStan\Type\FloatType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\NullType;
@@ -50,13 +49,13 @@ public function getTypeFromFunctionCall(
 				return $argType->toString();
 			case 'intval':
 				$type = $argType->toInteger();
-				return $type instanceof ErrorType ? new IntegerType() : $type;
+				return $type->isError()->yes() ? new IntegerType() : $type;
 			case 'boolval':
 				return $argType->toBoolean();
 			case 'floatval':
 			case 'doubleval':
 				$type = $argType->toFloat();
-				return $type instanceof ErrorType ? new FloatType() : $type;
+				return $type->isError()->yes() ? new FloatType() : $type;
 			default:
 				throw new ShouldNotHappenException();
 		}
diff --git a/src/Type/StaticType.php b/src/Type/StaticType.php
index 21622b5b93..fe0d295910 100644
--- a/src/Type/StaticType.php
+++ b/src/Type/StaticType.php
@@ -659,6 +659,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return $this;
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return $this->getStaticObjectType()->isError();
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return $this->getStaticObjectType()->isVoid();
diff --git a/src/Type/StrictMixedType.php b/src/Type/StrictMixedType.php
index 71678b77a4..643d986db8 100644
--- a/src/Type/StrictMixedType.php
+++ b/src/Type/StrictMixedType.php
@@ -330,6 +330,11 @@ public function isScalar(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function looseCompare(Type $type, PhpVersion $phpVersion): BooleanType
 	{
 		return new BooleanType();
diff --git a/src/Type/StringType.php b/src/Type/StringType.php
index 44fa96ab15..2a97ee42fc 100644
--- a/src/Type/StringType.php
+++ b/src/Type/StringType.php
@@ -86,7 +86,7 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $uni
 		}
 
 		$valueStringType = $valueType->toString();
-		if ($valueStringType instanceof ErrorType) {
+		if ($valueStringType->isError()->yes()) {
 			return new ErrorType();
 		}
 
diff --git a/src/Type/Traits/ArrayTypeTrait.php b/src/Type/Traits/ArrayTypeTrait.php
index 813b0136d9..15a004c4f5 100644
--- a/src/Type/Traits/ArrayTypeTrait.php
+++ b/src/Type/Traits/ArrayTypeTrait.php
@@ -179,6 +179,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return new ErrorType();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/Traits/LateResolvableTypeTrait.php b/src/Type/Traits/LateResolvableTypeTrait.php
index d35ee72461..aeaa9a69bc 100644
--- a/src/Type/Traits/LateResolvableTypeTrait.php
+++ b/src/Type/Traits/LateResolvableTypeTrait.php
@@ -523,6 +523,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return $this->resolve()->getObjectTypeOrClassStringObjectType();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return $this->resolve()->isError();
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return $this->resolve()->isVoid();
diff --git a/src/Type/Traits/ObjectTypeTrait.php b/src/Type/Traits/ObjectTypeTrait.php
index 51a4922f43..b4282a58dc 100644
--- a/src/Type/Traits/ObjectTypeTrait.php
+++ b/src/Type/Traits/ObjectTypeTrait.php
@@ -265,6 +265,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return $this;
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return TrinaryLogic::createNo();
diff --git a/src/Type/Type.php b/src/Type/Type.php
index e9cbca0b7a..1e316fc51e 100644
--- a/src/Type/Type.php
+++ b/src/Type/Type.php
@@ -292,6 +292,8 @@ public function isVoid(): TrinaryLogic;
 
 	public function isScalar(): TrinaryLogic;
 
+	public function isError(): TrinaryLogic;
+
 	public function looseCompare(Type $type, PhpVersion $phpVersion): BooleanType;
 
 	public function getSmallerType(PhpVersion $phpVersion): Type;
diff --git a/src/Type/TypehintHelper.php b/src/Type/TypehintHelper.php
index 076fedcacc..6796c7ddcc 100644
--- a/src/Type/TypehintHelper.php
+++ b/src/Type/TypehintHelper.php
@@ -85,7 +85,7 @@ public static function decideType(
 			return $type;
 		}
 
-		if ($phpDocType !== null && !$phpDocType instanceof ErrorType) {
+		if ($phpDocType !== null && !$phpDocType->isError()->yes()) {
 			if ($phpDocType instanceof NeverType && $phpDocType->isExplicit()) {
 				return $phpDocType;
 			}
diff --git a/src/Type/UnionType.php b/src/Type/UnionType.php
index a1855a713b..425dd2c9e5 100644
--- a/src/Type/UnionType.php
+++ b/src/Type/UnionType.php
@@ -732,6 +732,11 @@ public function getObjectTypeOrClassStringObjectType(): Type
 		return $this->unionTypes(static fn (Type $type): Type => $type->getObjectTypeOrClassStringObjectType());
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return $this->unionResults(static fn (Type $type): TrinaryLogic => $type->isError());
+	}
+
 	public function isVoid(): TrinaryLogic
 	{
 		return $this->unionResults(static fn (Type $type): TrinaryLogic => $type->isVoid());
@@ -769,7 +774,7 @@ public function getOffsetValueType(Type $offsetType): Type
 		$types = [];
 		foreach ($this->types as $innerType) {
 			$valueType = $innerType->getOffsetValueType($offsetType);
-			if ($valueType instanceof ErrorType) {
+			if ($valueType->isError()->yes()) {
 				continue;
 			}
 
diff --git a/src/Type/VoidType.php b/src/Type/VoidType.php
index 83c5a05726..f02857ee63 100644
--- a/src/Type/VoidType.php
+++ b/src/Type/VoidType.php
@@ -239,6 +239,11 @@ public function isScalar(): TrinaryLogic
 		return TrinaryLogic::createNo();
 	}
 
+	public function isError(): TrinaryLogic
+	{
+		return TrinaryLogic::createNo();
+	}
+
 	public function looseCompare(Type $type, PhpVersion $phpVersion): BooleanType
 	{
 		return new BooleanType();