scala.reflect.api

# Types

#### trait Types extends AnyRef

Self Type
  Universe
Source
  Types.scala

Linear Supertypes
AnyRef, Any
Known Subclasses
Context, Mirror, TreeBuildUtil, Universe
Ordering

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2. By inheritance

Inherited

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1. Types
2. AnyRef
3. Any

Visibility

1. Public
2. All

### Type Members

1. #### abstract class AbsType extends AnyRef

   This class declares operations that are visible in a Type.

2. #### abstract type AnnotatedType <: Type

3. #### abstract class AnnotatedTypeExtractor extends AnyRef

4. #### abstract type ClassInfoType <: CompoundType

   The `ClassInfo` type signature is used to define parents and declarations of classes, traits, and objects.

   The `ClassInfo` type signature is used to define parents and declarations of classes, traits, and objects. If a class, trait, or object C is declared like this

           C extends P_1 with ... with P_m { D_1; ...; D_n}

   its `ClassInfo` type has the following form:

           ClassInfo(List(P_1, ..., P_m), Scope(D_1, ..., D_n), C)

5. #### abstract class ClassInfoTypeExtractor extends AnyRef

   An extractor class to create and pattern match with syntax `ClassInfo(parents, decls, clazz)` Here, `parents` is the list of parent types of the class, `decls` is the scope containing all declarations in the class, and `clazz` is the symbol of the class itself.

6. #### abstract type CompoundType <: Type

   A subtype of Type representing refined types as well as `ClassInfo` signatures.

7. #### abstract type ConstantType <: SingletonType

   The `ConstantType` type is not directly written in user programs, but arises as the type of a constant.

   The `ConstantType` type is not directly written in user programs, but arises as the type of a constant. The REPL expresses constant types like Int(11). Here are some constants with their types.

           1           ConstantType(Constant(1))
           "abc"       ConstantType(Constant("abc"))

8. #### abstract class ConstantTypeExtractor extends AnyRef

   An extractor class to create and pattern match with syntax `ConstantType(constant)` Here, `constant` is the constant value represented by the type.

9. #### abstract type ExistentialType <: Type

10. #### abstract class ExistentialTypeExtractor extends AnyRef

11. #### abstract type MethodType <: Type

    The `MethodType` type signature is used to indicate parameters and result type of a method

12. #### abstract class MethodTypeExtractor extends AnyRef

    An extractor class to create and pattern match with syntax `MethodType(params, respte)` Here, `params` is a potentially empty list of parameter symbols of the method, and `restpe` is the result type of the method.

13. #### abstract type NullaryMethodType <: Type

14. #### abstract class NullaryMethodTypeExtractor extends AnyRef

15. #### abstract type PolyType <: Type

16. #### abstract class PolyTypeExtractor extends AnyRef

17. #### abstract type RefinedType <: CompoundType

    The `RefinedType` type defines types of any of the forms on the left, with their RefinedType representations to the right.

    The `RefinedType` type defines types of any of the forms on the left, with their RefinedType representations to the right.

            P_1 with ... with P_m { D_1; ...; D_n}      RefinedType(List(P_1, ..., P_m), Scope(D_1, ..., D_n))
            P_1 with ... with P_m                       RefinedType(List(P_1, ..., P_m), Scope())
            { D_1; ...; D_n}                            RefinedType(List(AnyRef), Scope(D_1, ..., D_n))

18. #### abstract class RefinedTypeExtractor extends AnyRef

    An extractor class to create and pattern match with syntax `RefinedType(parents, decls)` Here, `parents` is the list of parent types of the class, and `decls` is the scope containing all declarations in the class.

19. #### abstract type SingleType <: SingletonType

    The `SingleType` type describes types of any of the forms on the left, with their TypeRef representations to the right.

    The `SingleType` type describes types of any of the forms on the left, with their TypeRef representations to the right.

            (T # x).type             SingleType(T, x)
            p.x.type                 SingleType(p.type, x)
            x.type                   SingleType(NoPrefix, x)

20. #### abstract class SingleTypeExtractor extends AnyRef

    An extractor class to create and pattern match with syntax `SingleType(pre, sym)` Here, `pre` is the prefix of the single-type, and `sym` is the stable value symbol referred to by the single-type.

21. #### abstract type SingletonType >: Null <: Type

    The type of Scala singleton types, i.

    The type of Scala singleton types, i.e. types that are inhabited by only one nun-null value. These include types of the forms

           C.this.type
           C.super.type
           x.type

    as well as constant types.

22. #### abstract type SuperType <: SingletonType

    The `SuperType` type is not directly written, but arises when `C.super` is used as a prefix in a `TypeRef` or `SingleType`.

    The `SuperType` type is not directly written, but arises when `C.super` is used as a prefix in a `TypeRef` or `SingleType`. It's internal presentation is

            SuperType(thistpe, supertpe)

    Here, `thistpe` is the type of the corresponding this-type. For instance, in the type arising from C.super, the `thistpe` part would be `ThisType(C)`. `supertpe` is the type of the super class referred to by the `super`.

23. #### abstract class SuperTypeExtractor extends AnyRef

    An extractor class to create and pattern match with syntax `SingleType(thistpe, supertpe)`

24. #### abstract type ThisType <: SingletonType

    The `ThisType` type describes types of the form on the left with the correspnding ThisType representations to the right.

    The `ThisType` type describes types of the form on the left with the correspnding ThisType representations to the right.

            C.this.type             ThisType(C)

25. #### abstract class ThisTypeExtractor extends AnyRef

    An extractor class to create and pattern match with syntax `ThisType(sym)` where `sym` is the class prefix of the this type.

26. #### abstract type Type >: Null <: AbsType

    The type of Scala types, and also Scala type signatures.

    The type of Scala types, and also Scala type signatures. (No difference is internally made between the two).

27. #### abstract type TypeBounds <: Type

    The `TypeBounds` type signature is used to indicate lower and upper type bounds of type parameters and abstract types.

    The `TypeBounds` type signature is used to indicate lower and upper type bounds of type parameters and abstract types. It is not a first-class type. If an abstract type or type parameter is declared with any of the forms on the left, its type signature is the TypeBounds type on the right.

            T >: L <: U               TypeBounds(L, U)
            T >: L                    TypeBounds(L, Any)
            T <: U                    TypeBounds(Nothing, U)

28. #### abstract class TypeBoundsExtractor extends AnyRef

    An extractor class to create and pattern match with syntax `TypeBound(lower, upper)` Here, `lower` is the lower bound of the `TypeBounds` pair, and `upper` is the upper bound.

29. #### abstract type TypeRef <: Type

    The `TypeRef` type describes types of any of the forms on the left, with their TypeRef representations to the right.

    The `TypeRef` type describes types of any of the forms on the left, with their TypeRef representations to the right.

            T # C[T_1, ..., T_n]      TypeRef(T, C, List(T_1, ..., T_n))
            p.C[T_1, ..., T_n]        TypeRef(p.type, C, List(T_1, ..., T_n))
            C[T_1, ..., T_n]          TypeRef(NoPrefix, C, List(T_1, ..., T_n))
            T # C                     TypeRef(T, C, Nil)
            p.C                       TypeRef(p.type, C, Nil)
            C                         TypeRef(NoPrefix, C, Nil)

30. #### abstract class TypeRefExtractor extends AnyRef

    An extractor class to create and pattern match with syntax `TypeRef(pre, sym, args)` Here, `pre` is the prefix of the type reference, `sym` is the symbol referred to by the type reference, and `args` is a possible empty list of type argumenrts.

### Abstract Value Members

1. #### abstract val AnnotatedType: AnnotatedTypeExtractor

2. #### abstract val ClassInfoType: ClassInfoTypeExtractor

   The constructor/deconstructor for `ClassInfoType` instances.

3. #### abstract val ConstantType: ConstantTypeExtractor

   The constructor/deconstructor for `ConstantType` instances.

4. #### abstract val ExistentialType: ExistentialTypeExtractor

5. #### abstract val MethodType: MethodTypeExtractor

   The constructor/deconstructor for `MethodType` instances.

6. #### abstract val NoPrefix: Type

   This constant is used as a special value denoting the empty prefix in a path dependent type.

   This constant is used as a special value denoting the empty prefix in a path dependent type. For instance `x.type` is represented as `SingleType(NoPrefix, <x>)`, where `<x>` stands for the symbol for `x`.

7. #### abstract val NoType: Type

   This constant is used as a special value that indicates that no meaningful type exists.

8. #### abstract val NullaryMethodType: NullaryMethodTypeExtractor

9. #### abstract val PolyType: PolyTypeExtractor

10. #### abstract val RefinedType: RefinedTypeExtractor

    The constructor/deconstructor for `RefinedType` instances.

11. #### abstract val SingleType: SingleTypeExtractor

    The constructor/deconstructor for `SingleType` instances.

12. #### abstract val SuperType: SuperTypeExtractor

    The constructor/deconstructor for `SuperType` instances.

13. #### abstract val ThisType: ThisTypeExtractor

    The constructor/deconstructor for `ThisType` instances.

14. #### abstract val TypeBounds: TypeBoundsExtractor

    The constructor/deconstructor for `TypeBounds` instances.

15. #### abstract val TypeRef: TypeRefExtractor

    The constructor/deconstructor for `TypeRef` instances.

16. #### abstract def glb(ts: List[Type]): Type

    The greatest lower bound wrt <:< of a list of types

17. #### abstract def lub(xs: List[Type]): Type

    The least upper bound wrt <:< of a list of types

### Concrete Value Members

1. #### final def !=(arg0: AnyRef): Boolean

   Definition Classes
     AnyRef

2. #### final def !=(arg0: Any): Boolean

   Test two objects for inequality.

   Test two objects for inequality.

   returns

     `true` if !(this == that), false otherwise.

   Definition Classes
     Any

3. #### final def ##(): Int

   Equivalent to `x.hashCode` except for boxed numeric types and `null`.

   Equivalent to `x.hashCode` except for boxed numeric types and `null`. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For `null` returns a hashcode where `null.hashCode` throws a `NullPointerException`.

   returns

     a hash value consistent with ==

   Definition Classes
     AnyRef → Any

4. #### final def ==(arg0: AnyRef): Boolean

   Definition Classes
     AnyRef

5. #### final def ==(arg0: Any): Boolean

   Test two objects for equality.

   Test two objects for equality. The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

   returns

     `true` if the receiver object is equivalent to the argument; `false` otherwise.

   Definition Classes
     Any

6. #### final def asInstanceOf[T0]: T0

   Cast the receiver object to be of type `T0`.

   Cast the receiver object to be of type `T0`.

   Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression `1.asInstanceOf[String]` will throw a `ClassCastException` at runtime, while the expression `List(1).asInstanceOf[List[String]]` will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

   returns

     the receiver object.

   Definition Classes
     Any
   Exceptions thrown
     ClassCastException

     if the receiver object is not an instance of the erasure of type `T0`.

7. #### def clone(): AnyRef

   Create a copy of the receiver object.

   Create a copy of the receiver object.

   The default implementation of the `clone` method is platform dependent.

   returns

     a copy of the receiver object.

   Attributes
     protected[lang]
   Definition Classes
     AnyRef
   Annotations
     @throws()
   Note

     not specified by SLS as a member of AnyRef

8. #### final def eq(arg0: AnyRef): Boolean

   Tests whether the argument (`arg0`) is a reference to the receiver object (`this`).

   Tests whether the argument (`arg0`) is a reference to the receiver object (`this`).

   The `eq` method implements an equivalence relation on non-null instances of `AnyRef`, and has three additional properties:

   - It is consistent: for any non-null instances `x` and `y` of type `AnyRef`, multiple invocations of `x.eq(y)` consistently returns `true` or consistently returns `false`.
   - For any non-null instance `x` of type `AnyRef`, `x.eq(null)` and `null.eq(x)` returns `false`.
   - `null.eq(null)` returns `true`.

   When overriding the `equals` or `hashCode` methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (`o1 eq o2`), they should be equal to each other (`o1 == o2`) and they should hash to the same value (`o1.hashCode == o2.hashCode`).

   returns

     `true` if the argument is a reference to the receiver object; `false` otherwise.

   Definition Classes
     AnyRef

9. #### def equals(arg0: Any): Boolean

   The equality method for reference types.

   The equality method for reference types. Default implementation delegates to `eq`.

   See also `equals` in Any.

   returns

     `true` if the receiver object is equivalent to the argument; `false` otherwise.

   Definition Classes
     AnyRef → Any

10. #### def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the `finalize` method is invoked, as well as the interaction between `finalize` and non-local returns and exceptions, are all platform dependent.

    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws()
    Note

      not specified by SLS as a member of AnyRef

11. #### final def getClass(): Class[_]

    A representation that corresponds to the dynamic class of the receiver object.

    A representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

      a representation that corresponds to the dynamic class of the receiver object.

    Definition Classes
      AnyRef → Any
    Note

      not specified by SLS as a member of AnyRef

12. #### def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in Any.

    returns

      the hash code value for this object.

    Definition Classes
      AnyRef → Any

13. #### final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is `T0`.

    Test whether the dynamic type of the receiver object is `T0`.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression `1.isInstanceOf[String]` will return `false`, while the expression `List(1).isInstanceOf[List[String]]` will return `true`. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

      `true` if the receiver object is an instance of erasure of type `T0`; `false` otherwise.

    Definition Classes
      Any

14. #### final def ne(arg0: AnyRef): Boolean

    Equivalent to `!(this eq that)`.

    Equivalent to `!(this eq that)`.

    returns

      `true` if the argument is not a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef

15. #### final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

16. #### final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

17. #### final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
      AnyRef

18. #### def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

      a String representation of the object.

    Definition Classes
      AnyRef → Any

19. #### final def wait(): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws()

20. #### final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws()

21. #### final def wait(arg0: Long): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws()

### Inherited from AnyRef

### Inherited from Any