Scala Reflection Library2.13.17 < Back
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# Packages

-  package root
  Definition Classes
    root
-  package scala
  Definition Classes
    root
-  package reflect
  Definition Classes
    scala
-  package api

  EXPERIMENTAL

  EXPERIMENTAL

  The Scala Reflection API (located in scala-reflect.jar).

  In Scala 2.10.0, the Scala Reflection API and its implementation have an "experimental" status. This means that the API and the docs are not complete and can be changed in binary- and source-incompatible manner in 2.10.1. This also means that the implementation has some known issues.

  The following types are the backbone of the Scala Reflection API, and serve as a good starting point for information about Scala Reflection:

  - scala.reflect.api.Symbols
  - scala.reflect.api.Types
  - scala.reflect.api.Mirrors
  - scala.reflect.api.Universe

  For more information about Scala Reflection, see the Reflection Guide

  Definition Classes
    reflect
-  trait Internals extends AnyRef

  EXPERIMENTAL

  EXPERIMENTAL

  This trait assembles APIs occasionally necessary for performing low-level operations on reflection artifacts. See Internals#InternalApi for more information about nature, usefulness and compatibility guarantees of these APIs.

  Definition Classes
    api
- Compat
- CompatApi
- CompatToken
- FreeTermSymbol
- FreeTermSymbolApi
- FreeTypeSymbol
- FreeTypeSymbolApi
- Importer
- Internal
- InternalApi
- ReferenceToBoxed
- ReferenceToBoxedApi
- ReferenceToBoxedExtractor
- ReificationSupportApi

t

scala.reflect.api.Internals

# InternalApi

###

#### trait InternalApi extends AnyRef

Reflection API exhibits a tension inherent to experimental things: on the one hand we want it to grow into a beautiful and robust API, but on the other hand we have to deal with immaturity of underlying mechanisms by providing not very pretty solutions to enable important use cases.

In Scala 2.10, which was our first stab at reflection API, we didn't have a systematic approach to dealing with this tension, sometimes exposing too much of internals (e.g. Symbol.deSkolemize) and sometimes exposing too little (e.g. there's still no facility to change owners, to do typing transformations, etc). This resulted in certain confusion with some internal APIs living among public ones, scaring the newcomers, and some internal APIs only available via casting, which requires intimate knowledge of the compiler and breaks compatibility guarantees.

This led to creation of the `internal` API module for the reflection API, which provides advanced APIs necessary for macros that push boundaries of the state of the art, clearly demarcating them from the more or less straightforward rest and providing compatibility guarantees on par with the rest of the reflection API (full compatibility within minor releases, best effort towards backward compatibility within major releases, clear replacement path in case of rare incompatible changes in major releases).

The `internal` module itself (the value that implements InternalApi) isn't defined here, in scala.reflect.api.Universe, but is provided on per-implementation basis. Runtime API endpoint (scala.reflect.runtime.universe) provides `universe.compat: InternalApi`, whereas compile-time API endpoints (instances of scala.reflect.macros.Context) provide `c.compat: ContextInternalApi`, which extends `InternalApi` with additional universe-specific and context-specific functionality.

Self Type
  Universe.InternalApi
Source
  Internals.scala

Linear Supertypes
AnyRef, Any
Known Subclasses
ContextInternalApi, MacroInternalApi
Type Hierarchy
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Ordering

1. Grouped
2. Alphabetic
3. By Inheritance

Inherited

1. InternalApi
2. AnyRef
3. Any

Implicitly

1. by any2stringadd
2. by StringFormat
3. by Ensuring
4. by ArrowAssoc

1. Hide All
2. Show All

Visibility

1. Public
2. Protected

### Type Members

1.  trait DecoratorApi extends AnyRef

   See also

     Decorators

2.  abstract type Decorators <: DecoratorApi

   Syntactic conveniences for additional internal APIs for trees, symbols and types

### Abstract Value Members

1.  abstract def annotatedType(annotations: List[Universe.Annotation], underlying: Universe.Type): Universe.AnnotatedType

   A creator for `AnnotatedType` types.

2.  abstract def asFreeTerm(symbol: Universe.Symbol): Universe.FreeTermSymbol

   This symbol cast to a free term symbol.

   This symbol cast to a free term symbol.

   Exceptions thrown

     `ScalaReflectionException` if `isFreeTerm` is false.

3.  abstract def asFreeType(symbol: Universe.Symbol): Universe.FreeTypeSymbol

   This symbol cast to a free type symbol.

   This symbol cast to a free type symbol.

   Exceptions thrown

     `ScalaReflectionException` if `isFreeType` is false.

4.  abstract def boundedWildcardType(bounds: Universe.TypeBounds): Universe.BoundedWildcardType

   A creator for `BoundedWildcardType` types.

5.  abstract def classDef(sym: Universe.Symbol, impl: Universe.Template): Universe.ClassDef

   A factory method for `ClassDef` nodes.

6.  abstract def classInfoType(parents: List[Universe.Type], decls: Universe.Scope, typeSymbol: Universe.Symbol): Universe.ClassInfoType

   A creator for `ClassInfoType` types.

7.  abstract def constantType(value: Universe.Constant): Universe.ConstantType

   A creator for `ConstantType` types.

8.  abstract def createImporter(from0: Universe): Universe.Importer { val from: from0.type }

   Creates an importer that moves reflection artifacts between universes.

   Creates an importer that moves reflection artifacts between universes.

   See also

     Importer

9.  abstract def deSkolemize(symbol: Universe.Symbol): Universe.Symbol

   If this symbol is a skolem, its corresponding type parameter, otherwise the symbol itself.

   If this symbol is a skolem, its corresponding type parameter, otherwise the symbol itself.

   To quote Martin Odersky, skolems are synthetic type "constants" that are copies of existentially bound or universally bound type variables. E.g. if one is inside the right-hand side of a method:

       def foo[T](x: T) = ... foo[List[T]]....

   the skolem named `T` refers to the unknown type instance of `T` when `foo` is called. It needs to be different from the type parameter because in a recursive call as in the `foo[List[T]]` above the type parameter gets substituted with `List[T]`, but the type skolem stays what it is.

   The other form of skolem is an existential skolem. Say one has a function

       def bar(xs: List[T] forSome { type T }) = xs.head

   then each occurrence of `xs` on the right will have type `List[T']` where `T'` is a fresh copy of `T`.

10.  abstract val decorators: Decorators

    See also

      Decorators

11.  abstract def defDef(sym: Universe.Symbol, rhs: (List[List[Universe.Symbol]]) => Universe.Tree): Universe.DefDef

    A factory method for `DefDef` nodes.

12.  abstract def defDef(sym: Universe.Symbol, rhs: Universe.Tree): Universe.DefDef

    A factory method for `DefDef` nodes.

13.  abstract def defDef(sym: Universe.Symbol, mods: Universe.Modifiers, rhs: Universe.Tree): Universe.DefDef

    A factory method for `DefDef` nodes.

14.  abstract def defDef(sym: Universe.Symbol, vparamss: List[List[Universe.ValDef]], rhs: Universe.Tree): Universe.DefDef

    A factory method for `DefDef` nodes.

15.  abstract def defDef(sym: Universe.Symbol, mods: Universe.Modifiers, vparamss: List[List[Universe.ValDef]], rhs: Universe.Tree): Universe.DefDef

    A factory method for `DefDef` nodes.

16.  abstract def existentialAbstraction(tparams: List[Universe.Symbol], tpe0: Universe.Type): Universe.Type

    A creator for existential types.

    A creator for existential types. This generates:

        tpe1 where { tparams }

    where `tpe1` is the result of extrapolating `tpe` with regard to `tparams`. Extrapolating means that type variables in `tparams` occurring in covariant positions are replaced by upper bounds, (minus any SingletonClass markers), type variables in `tparams` occurring in contravariant positions are replaced by upper bounds, provided the resulting type is legal with regard to stability, and does not contain any type variable in `tparams`.

    The abstraction drops all type parameters that are not directly or indirectly referenced by type `tpe1`. If there are no remaining type parameters, simply returns result type `tpe`.

17.  abstract def existentialType(quantified: List[Universe.Symbol], underlying: Universe.Type): Universe.ExistentialType

    A creator for `ExistentialType` types.

18.  abstract def flags(symbol: Universe.Symbol): Universe.FlagSet

    Returns internal flags associated with the symbol.

19.  abstract def freeTerms(tree: Universe.Tree): List[Universe.FreeTermSymbol]

    Extracts free term symbols from a tree that is reified or contains reified subtrees.

20.  abstract def freeTypes(tree: Universe.Tree): List[Universe.FreeTypeSymbol]

    Extracts free type symbols from a tree that is reified or contains reified subtrees.

21.  abstract def fullyInitialize(scope: Universe.Scope): scope.type

    Calls initialize on all the symbols that the scope consists of.

22.  abstract def fullyInitialize(tp: Universe.Type): tp.type

    Calls initialize on all the value and type parameters of the type.

23.  abstract def fullyInitialize(symbol: Universe.Symbol): symbol.type

    Calls initialize on the owner and all the value and type parameters of the symbol.

24.  abstract def initialize(symbol: Universe.Symbol): symbol.type

    Forces all outstanding completers associated with this symbol.

    Forces all outstanding completers associated with this symbol. After this call returns, the symbol becomes immutable and thread-safe.

25.  abstract def intersectionType(tps: List[Universe.Type], owner: Universe.Symbol): Universe.Type

    A creator for intersection type where intersections of a single type are replaced by the type itself, and repeated parent classes are merged.

    A creator for intersection type where intersections of a single type are replaced by the type itself, and repeated parent classes are merged.

    !!! Repeated parent classes are not merged - is this a bug in the comment or in the code?

26.  abstract def intersectionType(tps: List[Universe.Type]): Universe.Type

    A creator for intersection type where intersections of a single type are replaced by the type itself.

27.  abstract def isErroneous(symbol: Universe.Symbol): Boolean

    Does this symbol or its underlying type represent a typechecking error?

28.  abstract def isFreeTerm(symbol: Universe.Symbol): Boolean

    Does this symbol represent a free term captured by reification? If yes, `isTerm` is also guaranteed to be true.

29.  abstract def isFreeType(symbol: Universe.Symbol): Boolean

    Does this symbol represent a free type captured by reification? If yes, `isType` is also guaranteed to be true.

30.  abstract def isSkolem(symbol: Universe.Symbol): Boolean

    Does this symbol represent the definition of a skolem? Skolems are used during typechecking to represent type parameters viewed from inside their scopes.

31.  abstract def labelDef(sym: Universe.Symbol, params: List[Universe.Symbol], rhs: Universe.Tree): Universe.LabelDef

    A factory method for `LabelDef` nodes.

32.  abstract def methodType(params: List[Universe.Symbol], resultType: Universe.Type): Universe.MethodType

    A creator for `MethodType` types.

33.  abstract def moduleDef(sym: Universe.Symbol, impl: Universe.Template): Universe.ModuleDef

    A factory method for `ModuleDef` nodes.

34.  abstract def newClassSymbol(owner: Universe.Symbol, name: Universe.TypeName, pos: Universe.Position = NoPosition, flags: Universe.FlagSet = NoFlags): Universe.ClassSymbol
35.  abstract def newFreeTerm(name: String, value: => Any, flags: Universe.FlagSet = NoFlags, origin: String = null): Universe.FreeTermSymbol
36.  abstract def newFreeType(name: String, flags: Universe.FlagSet = NoFlags, origin: String = null): Universe.FreeTypeSymbol
37.  abstract def newMethodSymbol(owner: Universe.Symbol, name: Universe.TermName, pos: Universe.Position = NoPosition, flags: Universe.FlagSet = NoFlags): Universe.MethodSymbol
38.  abstract def newModuleAndClassSymbol(owner: Universe.Symbol, name: Universe.Name, pos: Universe.Position = NoPosition, flags: Universe.FlagSet = NoFlags): (Universe.ModuleSymbol, Universe.ClassSymbol)
39.  abstract def newScopeWith(elems: Universe.Symbol*): Universe.Scope

    Create a new scope with the given initial elements.

40.  abstract def newTermSymbol(owner: Universe.Symbol, name: Universe.TermName, pos: Universe.Position = NoPosition, flags: Universe.FlagSet = NoFlags): Universe.TermSymbol
41.  abstract def newTypeSymbol(owner: Universe.Symbol, name: Universe.TypeName, pos: Universe.Position = NoPosition, flags: Universe.FlagSet = NoFlags): Universe.TypeSymbol
42.  abstract def nullaryMethodType(resultType: Universe.Type): Universe.NullaryMethodType

    A creator for `NullaryMethodType` types.

43.  abstract def polyType(tparams: List[Universe.Symbol], tpe: Universe.Type): Universe.PolyType

    A creator for type parameterizations that strips empty type parameter lists.

    A creator for type parameterizations that strips empty type parameter lists. Use this factory method to indicate the type has kind * (it's a polymorphic value) until we start tracking explicit kinds equivalent to typeFun (except that the latter requires tparams nonEmpty).

44.  abstract def refinedType(parents: List[Universe.Type], owner: Universe.Symbol, decls: Universe.Scope, pos: Universe.Position): Universe.Type

    A creator for `RefinedType` types.

45.  abstract def refinedType(parents: List[Universe.Type], owner: Universe.Symbol, decls: Universe.Scope): Universe.Type

    A creator for `RefinedType` types.

46.  abstract def refinedType(parents: List[Universe.Type], owner: Universe.Symbol): Universe.Type

    A creator for `RefinedType` types.

47.  abstract def refinedType(parents: List[Universe.Type], decls: Universe.Scope, clazz: Universe.Symbol): Universe.RefinedType

    A creator for `RefinedType` types.

48.  abstract def refinedType(parents: List[Universe.Type], decls: Universe.Scope): Universe.RefinedType

    A creator for `RefinedType` types.

49.  abstract val reificationSupport: Universe.ReificationSupportApi

    This is an internal implementation module.

50.  abstract def singleType(pre: Universe.Type, sym: Universe.Symbol): Universe.Type

    A creator for `SingleType` types.

51.  abstract def substituteSymbols(tree: Universe.Tree, from: List[Universe.Symbol], to: List[Universe.Symbol]): Universe.Tree

    Substitute symbols in `to` for corresponding occurrences of references to symbols `from` in this type.

52.  abstract def substituteThis(tree: Universe.Tree, clazz: Universe.Symbol, to: => Universe.Tree): Universe.Tree

    Substitute given tree `to` for occurrences of nodes that represent `C.this`, where `C` refers to the given class `clazz`.

53.  abstract def substituteTypes(tree: Universe.Tree, from: List[Universe.Symbol], to: List[Universe.Type]): Universe.Tree

    Substitute types in `to` for corresponding occurrences of references to symbols `from` in this tree.

54.  abstract def superType(thistpe: Universe.Type, supertpe: Universe.Type): Universe.Type

    A creator for `SuperType` types.

55.  abstract def thisType(sym: Universe.Symbol): Universe.Type

    A creator for `ThisType` types.

56.  abstract def typeBounds(lo: Universe.Type, hi: Universe.Type): Universe.TypeBounds

    A creator for `TypeBounds` types.

57.  abstract def typeDef(sym: Universe.Symbol): Universe.TypeDef

    A factory method for `TypeDef` nodes.

58.  abstract def typeDef(sym: Universe.Symbol, rhs: Universe.Tree): Universe.TypeDef

    A factory method for `TypeDef` nodes.

59.  abstract def typeRef(pre: Universe.Type, sym: Universe.Symbol, args: List[Universe.Type]): Universe.Type

    A creator for `TypeRef` types.

60.  abstract def valDef(sym: Universe.Symbol): Universe.ValDef

    A factory method for `ValDef` nodes.

61.  abstract def valDef(sym: Universe.Symbol, rhs: Universe.Tree): Universe.ValDef

    A factory method for `ValDef` nodes.

### Concrete Value Members

1.  final def !=(arg0: Any): Boolean
   Definition Classes
     AnyRef → Any
2.  final def ##: Int
   Definition Classes
     AnyRef → Any
3.  def +(other: String): String
   Implicit
     This member is added by an implicit conversion from Universe.InternalApi toany2stringadd[Universe.InternalApi] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd
4.  def ->[B](y: B): (Universe.InternalApi, B)
   Implicit
     This member is added by an implicit conversion from Universe.InternalApi toArrowAssoc[Universe.InternalApi] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()
5.  final def ==(arg0: Any): Boolean
   Definition Classes
     AnyRef → Any
6.  final def asInstanceOf[T0]: T0
   Definition Classes
     Any
7.  def clone(): AnyRef
   Attributes
     protected[lang]
   Definition Classes
     AnyRef
   Annotations
     @throws(classOf[java.lang.CloneNotSupportedException]) @native()
8.  def ensuring(cond: (Universe.InternalApi) => Boolean, msg: => Any): Universe.InternalApi
   Implicit
     This member is added by an implicit conversion from Universe.InternalApi toEnsuring[Universe.InternalApi] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring
9.  def ensuring(cond: (Universe.InternalApi) => Boolean): Universe.InternalApi
   Implicit
     This member is added by an implicit conversion from Universe.InternalApi toEnsuring[Universe.InternalApi] performed by method Ensuring in scala.Predef.
   Definition Classes
     Ensuring
10.  def ensuring(cond: Boolean, msg: => Any): Universe.InternalApi
    Implicit
      This member is added by an implicit conversion from Universe.InternalApi toEnsuring[Universe.InternalApi] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
11.  def ensuring(cond: Boolean): Universe.InternalApi
    Implicit
      This member is added by an implicit conversion from Universe.InternalApi toEnsuring[Universe.InternalApi] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
12.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
13.  def equals(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef → Any
14.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.Throwable])
15.  final def getClass(): Class[_ <: AnyRef]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
16.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
17.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
18.  def manifestToTypeTag[T](mirror: Any, manifest: Manifest[T]): Universe.TypeTag[T]

    Convert a scala.reflect.Manifest to a scala.reflect.api.TypeTags#TypeTag.

    Convert a scala.reflect.Manifest to a scala.reflect.api.TypeTags#TypeTag.

    Compiler usually generates these conversions automatically, when a manifest for a type `T` is in scope, and an implicit of type `TypeTag[T]` is requested, but this method can also be called manually. For example:

        manifestToTypeTag(scala.reflect.runtime.currentMirror, implicitly[Manifest[String]])

19.  def markForAsyncTransform(owner: Universe.Symbol, method: Universe.DefDef, awaitSymbol: Universe.Symbol, config: Map[String, AnyRef]): Universe.DefDef

    Mark the given `DefDef` for later processing by the `async` phase of the compiler

    Mark the given `DefDef` for later processing by the `async` phase of the compiler

    owner

      current owner the owner of the call site being transformed into an async state machine

    method

      A method of the form `def $name($paramName: $ParamType): $T = $CODE`, where calls to `$CODE` `awaitSymbol` in `$CODE` mark continuation points.

    awaitSymbol

      The `await` method, of a typically of a type like `[T](Future[T): T`

    config

      Untyped channel for additional configuration parameters. This currently allows

      - "postAnfTransform" : A function from `Block => Block`
      - "stateDiagram" : A function from `(Symbol, Tree) => Option[String => Unit]` that can opt to receive a .dot diagram of the state machine.
20.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
21.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
22.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
23.  final def synchronized[T0](arg0: => T0): T0
    Definition Classes
      AnyRef
24.  def toString(): String
    Definition Classes
      AnyRef → Any
25.  def typeTagToManifest[T](mirror: Any, tag: Universe.TypeTag[T])(implicit arg0: ClassTag[T]): Manifest[T]

    Convert a scala.reflect.api.TypeTags#TypeTag to a scala.reflect.Manifest.

    Convert a scala.reflect.api.TypeTags#TypeTag to a scala.reflect.Manifest.

    Compiler usually generates these conversions automatically, when a type tag for a type `T` is in scope, and an implicit of type `Manifest[T]` is requested, but this method can also be called manually. For example:

        typeTagToManifest(scala.reflect.runtime.currentMirror, implicitly[TypeTag[String]])

26.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
27.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
28.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException]) @native()

### Deprecated Value Members

1.  def formatted(fmtstr: String): String
   Implicit
     This member is added by an implicit conversion from Universe.InternalApi toStringFormat[Universe.InternalApi] performed by method StringFormat in scala.Predef.
   Definition Classes
     StringFormat
   Annotations
     @deprecated @inline()
   Deprecated

     (Since version 2.12.16) Use `formatString.format(value)` instead of `value.formatted(formatString)`, or use the `f""` string interpolator. In Java 15 and later, `formatted` resolves to the new method in String which has reversed parameters.

2.  def →[B](y: B): (Universe.InternalApi, B)
   Implicit
     This member is added by an implicit conversion from Universe.InternalApi toArrowAssoc[Universe.InternalApi] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @deprecated
   Deprecated

     (Since version 2.13.0) Use `->` instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd fromUniverse.InternalApi to any2stringadd[Universe.InternalApi]

### Inherited by implicit conversion StringFormat fromUniverse.InternalApi to StringFormat[Universe.InternalApi]

### Inherited by implicit conversion Ensuring fromUniverse.InternalApi to Ensuring[Universe.InternalApi]

### Inherited by implicit conversion ArrowAssoc fromUniverse.InternalApi to ArrowAssoc[Universe.InternalApi]

### TagInterop

### TypeCreators

### Ungrouped