Scala Compiler2.12.21 < Back
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# Packages

-  package root

  The Scala compiler and reflection APIs.

  The Scala compiler and reflection APIs.

  Definition Classes
    root
-  package scala
  Definition Classes
    root
-  package reflect
  Definition Classes
    scala
-  package reify
  Definition Classes
    reflect
-  package codegen
  Definition Classes
    reify
-  package phases
  Definition Classes
    reify
-  package utils
  Definition Classes
    reify
- Errors
- Phases
- Reifier
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- Taggers

t

scala.reflect.reify

# Phases 

###

#### trait Phases extends Reshape with Calculate with Metalevels with Reify

Self Type
  Reifier
Source
  Phases.scala

Linear Supertypes
Reify, GenUtils, GenPositions, GenAnnotationInfos, GenTrees, GenNames, GenTypes, GenSymbols, Metalevels, Calculate, Reshape, AnyRef, Any
Known Subclasses
ApplyReifier, Reifier, UnapplyReifier, Reifier
 
Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. Phases
2. Reify
3. GenUtils
4. GenPositions
5. GenAnnotationInfos
6. GenTrees
7. GenNames
8. GenTypes
9. GenSymbols
10. Metalevels
11. Calculate
12. Reshape
13. AnyRef
14. Any

Implicitly

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

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Visibility

1. Public
2. All

### Type Members

1.  case class Reification(name: tools.nsc.Global.Name, binding: tools.nsc.Global.Tree, tree: tools.nsc.Global.Tree) extends Product with Serializable
   Definition Classes
     GenSymbols
2.  implicit class RichCalculateSymbol extends AnyRef
   Definition Classes
     Calculate
3.  implicit class RichCalculateType extends AnyRef
   Definition Classes
     Calculate

### 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 Phases to any2stringadd[Phases] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd
4.  def ->[B](y: B): (Phases, B)
   Implicit
     This member is added by an implicit conversion from Phases to ArrowAssoc[Phases] 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 boundSymbolsInCallstack: List[tools.nsc.Global.Symbol]
   Definition Classes
     Reify
8.  val calculate: tools.nsc.Global.Traverser { ... /* 2 definitions in type refinement */ }

   Merely traverses the reifiee and records symbols local to the reifee along with their metalevels.

   Merely traverses the reifiee and records symbols local to the reifee along with their metalevels.

   Definition Classes
     Calculate
9.  def call(fname: String, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
   Definition Classes
     GenUtils
10.  def clone(): AnyRef
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( ... ) @native()
11.  def current: Any
    Definition Classes
      Reify
12.  def currents: List[Any]
    Definition Classes
      Reify
13.  def ensuring(cond: (Phases) ⇒ Boolean, msg: ⇒ Any): Phases
    Implicit
      This member is added by an implicit conversion from Phases to Ensuring[Phases] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
14.  def ensuring(cond: (Phases) ⇒ Boolean): Phases
    Implicit
      This member is added by an implicit conversion from Phases to Ensuring[Phases] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
15.  def ensuring(cond: Boolean, msg: ⇒ Any): Phases
    Implicit
      This member is added by an implicit conversion from Phases to Ensuring[Phases] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
16.  def ensuring(cond: Boolean): Phases
    Implicit
      This member is added by an implicit conversion from Phases to Ensuring[Phases] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
17.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
18.  def equals(arg0: Any): Boolean
    Definition Classes
      AnyRef → Any
19.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )
20.  final def getClass(): Class[_]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
21.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
22.  def isCrossStageTypeBearer(tree: tools.nsc.Global.Tree): Boolean
    Definition Classes
      GenUtils
23.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
24.  def isSemiConcreteTypeMember(tpe: tools.nsc.Global.Type): Boolean
    Definition Classes
      GenUtils
25.  val metalevels: tools.nsc.Global.Transformer { ... /* 4 definitions in type refinement */ }

    Makes sense of cross-stage bindings.

    Makes sense of cross-stage bindings.

    Analysis of cross-stage bindings becomes convenient if we introduce the notion of metalevels. Metalevel of a tree is a number that gets incremented every time you reify something and gets decremented when you splice something. Metalevel of a symbol is equal to the metalevel of its definition.

    Example 1. Consider the following snippet:

    reify { val x = 2 // metalevel of symbol x is 1, because it's declared inside reify val y = reify{x} // metalevel of symbol y is 1, because it's declared inside reify // metalevel of Ident(x) is 2, because it's inside two reifies y.splice // metalevel of Ident(y) is 0, because it's inside a designator of a splice }

    Cross-stage bindings are introduced when symbol.metalevel != curr_metalevel. Both bindings introduced in Example 1 are cross-stage.

    Depending on what side of the inequality is greater, the following situations might occur:

    1) symbol.metalevel < curr_metalevel. In this case reifier will generate a free variable that captures both the name of the symbol (to be compiled successfully) and its value (to be run successfully). For example, x in Example 1 will be reified as follows: Ident(newFreeVar("x", IntTpe, x))

    2) symbol.metalevel > curr_metalevel. This leads to a metalevel breach that violates intuitive perception of splicing. As defined in macro spec, splicing takes a tree and inserts it into another tree - as simple as that. However, how exactly do we do that in the case of y.splice? In this very scenario we can use dataflow analysis and inline it, but what if y were a var, and what if it were calculated randomly at runtime?

    This question has a genuinely simple answer. Sure, we cannot resolve such splices statically (i.e. during macro expansion of `reify`), but now we have runtime toolboxes, so noone stops us from picking up that reified tree and evaluating it at runtime (in fact, this is something that `Expr.splice` does transparently).

    This is akin to early vs late binding dilemma. The prior is faster, plus, the latter (implemented with reflection) might not work because of visibility issues or might be not available on all platforms. But the latter still has its uses, so I'm allowing metalevel breaches, but introducing the -Xlog-runtime-evals to log them.

    upd. We no longer do that. In case of a runaway `splice` inside a `reify`, one will get a static error. Why? Unfortunately, the cute idea of transparently converting between static and dynamic splices has failed. 1) Runtime eval that services dynamic splices requires scala-compiler.jar, which might not be on library classpath 2) Runtime eval incurs a severe performance penalty, so it'd better to be explicit about it

    As we can see, the only problem is the fact that lhs'es of `splice` can be code blocks that can capture variables from the outside. Code inside the lhs of an `splice` is not reified, while the code from the enclosing reify is.

    Hence some bindings become cross-stage, which is not bad per se (in fact, some cross-stage bindings have sane semantics, as in the example above). However this affects freevars, since they are delicate inter-dimensional beings that refer to both current and next planes of existence. When splicing tears the fabric of the reality apart, some freevars have to go single-dimensional to retain their sanity.

    Example 2. Consider the following snippet:

    reify { val x = 2 reify{x}.splice }

    Since the result of the inner reify is wrapped in a splice, it won't be reified together with the other parts of the outer reify, but will be inserted into that result verbatim.

    The inner reify produces an Expr[Int] that wraps Ident(freeVar("x", IntTpe, x)). However the freevar the reification points to will vanish when the compiler processes the outer reify. That's why we need to replace that freevar with a regular symbol that will point to reified x.

    Example 3. Consider the following fragment:

    reify { val x = 2 val y = reify{x} y.splice }

    In this case the inner reify doesn't appear next to splice, so it will be reified together with x. This means that no special processing is needed here.

    Example 4. Consider the following fragment:

    reify { val x = 2 { val y = 2 val z = reify{reify{x + y}} z.splice }.splice }

    The reasoning from Example 2 still holds here - we do need to inline the freevar that refers to x. However, we must not touch anything inside the splice'd block, because it's not getting reified.

    Definition Classes
      Metalevels
26.  def mirrorBuildCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
27.  def mirrorCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
28.  def mirrorFactoryCall(prefix: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
29.  def mirrorFactoryCall(value: Product, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
30.  def mirrorMirrorCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
31.  def mirrorMirrorSelect(name: tools.nsc.Global.TermName): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
32.  def mirrorSelect(name: tools.nsc.Global.TermName): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
33.  def mirrorSelect(name: String): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
34.  def mkList(args: List[tools.nsc.Global.Tree]): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
35.  def mkListMap(args: List[tools.nsc.Global.Tree]): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
36.  lazy val mkReificationPipeline: (tools.nsc.Global.Tree) ⇒ tools.nsc.Global.Tree
37.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
38.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
39.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
40.  def origin(sym: tools.nsc.Global.Symbol): String
    Definition Classes
      GenUtils
41.  def path(fullname: String, mkName: (String) ⇒ tools.nsc.Global.Name): tools.nsc.Global.Tree

    An (unreified) path that refers to definition with given fully qualified name

    An (unreified) path that refers to definition with given fully qualified name

    mkName

      Creator for last portion of name (either TermName or TypeName)

    Definition Classes
      GenUtils
42.  def reificationIsConcrete: Boolean

    Keeps track of whether this reification contains abstract type parameters

    Keeps track of whether this reification contains abstract type parameters

    Definition Classes
      GenTypes
43.  def reify(reifee: Any): tools.nsc.Global.Tree

    Reifies any supported value.

    Reifies any supported value. For internal use only, use `reified` instead.

    Definition Classes
      Reify
44.  def reifyAnnotationInfo(ann: tools.nsc.Global.AnnotationInfo): tools.nsc.Global.Tree
    Definition Classes
      GenAnnotationInfos
45.  def reifyBuildCall(name: tools.nsc.Global.TermName, args: Any*): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
46.  def reifyFlags(flags: tools.nsc.Global.FlagSet): tools.nsc.Global.Tree
    Definition Classes
      GenTrees
47.  def reifyFreeTerm(binding: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
      GenSymbols
48.  def reifyFreeType(binding: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
      GenSymbols
49.  def reifyList(xs: List[Any]): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
50.  def reifyMirrorObject(x: Product): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
51.  def reifyMirrorObject(name: String): tools.nsc.Global.Tree

    Reify a case object defined in Mirror

    Reify a case object defined in Mirror

    Definition Classes
      GenUtils
52.  def reifyModifiers(m: tools.nsc.Global.Modifiers): tools.nsc.Global.Tree
    Definition Classes
      GenTrees
53.  def reifyName(name: tools.nsc.Global.Name): tools.nsc.Global.Tree
    Definition Classes
      GenNames
54.  def reifyPosition(pos: tools.nsc.Global.Position): tools.nsc.Global.Tree
    Definition Classes
      GenPositions
55.  def reifyProduct(prefix: String, elements: List[Any]): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
56.  def reifyProduct(x: Product): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
57.  def reifySymDef(sym: tools.nsc.Global.Symbol): tools.nsc.Global.Tree
    Definition Classes
      GenSymbols
58.  def reifySymRef(sym: tools.nsc.Global.Symbol): tools.nsc.Global.Tree

    Reify a reference to a symbol

    Reify a reference to a symbol

    Definition Classes
      GenSymbols
59.  def reifyTree(tree: tools.nsc.Global.Tree): tools.nsc.Global.Tree

    Reify a tree.

    Reify a tree. For internal use only, use `reified` instead.

    Definition Classes
      GenTrees
60.  def reifyTreeSymbols: Boolean
    Definition Classes
      GenTrees
61.  def reifyTreeSyntactically(tree: tools.nsc.Global.Tree): tools.nsc.Global.Tree
    Definition Classes
      GenTrees
62.  def reifyTreeTypes: Boolean
    Definition Classes
      GenTrees
63.  def reifyType(tpe: tools.nsc.Global.Type): tools.nsc.Global.Tree

    Reify a type.

    Reify a type. For internal use only, use `reified` instead.

    Definition Classes
      GenTypes
64.  val reshape: tools.nsc.Global.Transformer { ... /* 2 definitions in type refinement */ }

    Rolls back certain changes that were introduced during typechecking of the reifee.

    Rolls back certain changes that were introduced during typechecking of the reifee.

    These include: * Undoing macro expansions * Replacing type trees with TypeTree(tpe) * Reassembling CompoundTypeTrees into reifiable form * Transforming Modifiers.annotations into Symbol.annotations * Transforming Annotated annotations into AnnotatedType annotations * Transforming Annotated(annot, expr) into Typed(expr, TypeTree(Annotated(annot, _)) * Non-idempotencies of the typechecker: https://github.com/scala/bug/issues/5464

    Definition Classes
      Reshape
65.  def scalaFactoryCall(name: String, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
66.  def scalaFactoryCall(name: tools.nsc.Global.TermName, args: tools.nsc.Global.Tree*): tools.nsc.Global.Tree
    Definition Classes
      GenUtils
67.  def spliceType(tpe: tools.nsc.Global.Type): tools.nsc.Global.Tree
    Definition Classes
      GenTypes
68.  def symtab: Reifier.SymbolTable

    Symbol table of the reifee.

    Symbol table of the reifee.

    Keeps track of auxiliary symbols that are necessary for this reification session. These include: 1) Free vars (terms, types and existentials), 2) Non-locatable symbols (sometimes, e.g. for RefinedTypes, we need to reify these; to do that we create their copies in the reificode) 3) Non-locatable symbols that are referred by #1, #2 and #3

    Exposes three main methods: 1) `syms` that lists symbols belonging to the table, 2) `symXXX` family of methods that provide information about the symbols in the table, 3) `encode` that renders the table into a list of trees (recursively populating #3 and setting up initialization code for #1, #2 and #3)

    Definition Classes
      GenSymbols
69.  final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
      AnyRef
70.  def termPath(fullname: String): tools.nsc.Global.Tree

    An (unreified) path that refers to term definition with given fully qualified name

    An (unreified) path that refers to term definition with given fully qualified name

    Definition Classes
      GenUtils
71.  def toString(): String
    Definition Classes
      AnyRef → Any
72.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
73.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
74.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... ) @native()
75.  def →[B](y: B): (Phases, B)
    Implicit
      This member is added by an implicit conversion from Phases to ArrowAssoc[Phases] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc
76.  object TypedOrAnnotated
    Definition Classes
      GenUtils

### Deprecated Value Members

1.  def formatted(fmtstr: String): String
   Implicit
     This member is added by an implicit conversion from Phases to StringFormat[Phases] 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.

### Inherited from Reify

### Inherited from GenUtils

### Inherited from GenPositions

### Inherited from GenAnnotationInfos

### Inherited from GenTrees

### Inherited from GenNames

### Inherited from GenTypes

### Inherited from GenSymbols

### Inherited from Metalevels

### Inherited from Calculate

### Inherited from Reshape

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from Phases to any2stringadd[Phases]

### Inherited by implicit conversion StringFormat from Phases to StringFormat[Phases]

### Inherited by implicit conversion Ensuring from Phases to Ensuring[Phases]

### Inherited by implicit conversion ArrowAssoc from Phases to ArrowAssoc[Phases]

### Ungrouped