Kotlin Analysis API Documentation Help

KaType

Represents a Kotlin type. It serves as the base interface for various specific type.

Hierarchy

Inherits from KaAnnotated.

Members

val abbreviation: KaUsualClassType?

The abbreviated type for the given expanded type, or null if this type has not been expanded, or the abbreviated type cannot be resolved.

An abbreviated type is an expanded type alias application. For example, if we have a type alias typealias MyString = String and its application MyString, String would be the type alias expansion and MyString its abbreviated type.

val nullability: KaTypeNullability

The type nullability: NULLABLE, NON_NULLABLE, UNKNOWN (for flexible types).

Subtypes

The KaType interface has several subtypes that represent different kinds of types in Kotlin:

  • KaClassType: Represents a Kotlin class type, encompassing classes, interfaces, objects, and enum classes.

    • KaUsualClassType: Represents a class type that is not a function type.

    • KaFunctionType: Represents Kotlin function types, including regular functions, suspend functions, and those with receivers.

  • KaTypeParameterType: Represents a type parameter type, such as T in the declaration class Box<T>(val element: T).

  • KaDefinitelyNotNullType: Represents a type that is known to be non-nullable at a particular point in the program.

  • KaCapturedType: Represents a type that is captured during type inference, often occurring when working with generics and variance.

  • KaFlexibleType: Represents a type with flexibility in its bounds, commonly used for platform types or types with uncertain nullability.

  • KaIntersectionType: Represents a type formed by the intersection of multiple types.

  • KaDynamicType: Represents the dynamic type in Kotlin, used for interoperability with dynamically-typed languages or platforms.

  • KaErrorType: Represents an unresolved type of some kind.

Transformation utilities

val Iterable<KaType>.commonSupertype: KaType

The common super type of the given collection of [KaType]. The collection must not be empty.

fun KaType.withNullability(newNullability: KaTypeNullability): KaType

Returns the given type with the modified nullability.

Nullability utilities

val KaType.canBeNull: Boolean

true if a public value of the given type can potentially be null.

This means this type is not a subtype of [Any]. However, it does not mean one can assign null to a variable of this type because it may be unknown if this type can accept null.

val KaType.isMarkedNullable: Boolean

true if the given type is explicitly marked as nullable. This means it is safe to assign null to a variable with this type.

val KaType.hasFlexibleNullability: Boolean

true if the given type is a flexible (platform) type, can both safe and ordinary calls are valid on it.

fun KaType.upperBoundIfFlexible(): KaType

Returns the upper bound if the given type is a flexible type, and the given type itself otherwise.

fun KaType.lowerBoundIfFlexible(): KaType

Returns the lower bound if the given type is a flexible type, and the given type itself otherwise.

Type relation utilities

fun KaType.semanticallyEquals(other: KaType, errorTypePolicy: KaSubtypingErrorTypePolicy = KaSubtypingErrorTypePolicy.STRICT): Boolean

Check semantic type equality. Returns true if the given type can be used instead of other.

fun KaType.isSubtypeOf(supertype: KaType, errorTypePolicy: KaSubtypingErrorTypePolicy = KaSubtypingErrorTypePolicy.STRICT): Boolean

Check if the given type is a subtype of the supertype.

fun KaType.isClassType(classId: ClassId): Boolean

true if the given type is a class type with the given ClassId, or its nullable version.

fun KaType.hasCommonSubtypeWith(that: KaType): Boolean

Check whether the given type is compatible with the other type. Compatibility means the types can have a common subtype.

val KaType.directSupertypes: Sequence<KaType>

Direct super types of the given type. For example, for MutableList<String> it will be List<String> and MutableCollection<String>.

val KaType.allSupertypes: Sequence<KaType>

All supertypes of the given type.

val KaType.isArrayOrPrimitiveArray: Boolean

true if the given type is an array or a primitive array type.

val KaType.isNestedArray: Boolean

true if the given type is an array or a primitive array type, and if its element is also an array type.

val KaType.isPrimitive: Boolean

true if the given [KaType] is one of these types: Byte, Short, Int, Long, Float, Double, Char, Boolean, or a nullable version of them.

val KaType.isAnyType
val KaType.isNothingType
val KaType.isUnitType
val KaType.isByteType
val KaType.isUByteType
val KaType.isShortType
val KaType.isUShortType
val KaType.isIntType
val KaType.isUIntType
val KaType.isLongType
val KaType.isULongType
val KaType.isFloatType
val KaType.isDoubleType
val KaType.isCharType
val KaType.isBooleanType
val KaType.isCharSequenceType
val KaType.isStringType

true if the given type is the specified Kotlin type or its nullable version.

val KaType.isFunctionalInterface: Boolean

true if the given type is a functional interface type (SAM type), e.g., Runnable.

val KaType.isFunctionType: Boolean

true if this type is a kotlin.Function type.

val KaType.isKFunctionType: Boolean

true if this type is a kotlin.reflect.KFunction type.

val KaType.isSuspendFunctionType: Boolean

true if this type is a kotlin.coroutines.SuspendFunction type.

val KaType.isKSuspendFunctionType: Boolean

true if this type is a kotlin.reflect.KSuspendFunction type.

val KaType.functionTypeKind: FunctionTypeKind?

The FunctionTypeKind of the given type, or null if the type is not a function type.

Experimental API.

Scope utilities

val KaType.scope: KaTypeScope?

Return a KaTypeScope for a given type. The type scope includes all members which are declared and callable on a given type.

Comparing to a KaScope, in the KaTypeScope all use-site type parameters are substituted.

Experimental API.

val KaType.syntheticJavaPropertiesScope: KaTypeScope?

A KaTypeScope with synthetic Java properties created for a given type.

Other utilities

val builtinTypes: KaBuiltinTypes

An instance providing access to all built-in Kotlin types, including number types, Any, Nothing, String and others.

val KaType.arrayElementType: KaType?

The array element type for a primitive type array or Array, null otherwise.

val KaType.expandedSymbol: KaClassSymbol?

The class symbol backing the given type, or null if the type has no expansion.

val KaType.fullyExpandedType: KaType

The type with type aliases recursively expanded.

val KaType.isDenotable: Boolean

true if this type is denotable. In other words, it can be written in Kotlin by a developer. Flexible type is an example of a non-denotable type.

val KaType.enhancedType: KaType?

The warning-level enhanced type for the given type, or null if it is absent.

Experimental API.

val KaType.enhancedTypeOrSelf: KaType?

The warning-level enhanced type for the given type, or the given type itself if it is absent.

Experimental API.

fun KaType.render(renderer: KaTypeRenderer = KaTypeRendererForSource.WITH_QUALIFIED_NAMES, position: Variance): String

Render the given type to a String. The particular rendering strategy is defined by the renderer.

Experimental API.

Last modified: 30 May 2025
TypesKaClassType