Scala Compiler2.13.2 < 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 tools
  Definition Classes
    scala
-  package nsc
  Definition Classes
    tools
-  package typechecker
  Definition Classes
    nsc
- Adaptations
- Analyzer
- AnalyzerPlugins
- Checkable
- ConstantFolder
- ContextErrors
- ContextMode
- Contexts
- DestructureTypes
- Duplicators
- EtaExpansion
- Fingerprint
- Implicits
- ImplicitsStats
- Infer
- MacroAnnotationAttachments
- MacroAnnotationNamers
- Macros
- MacrosStats
- MethodSynthesis
- Namers
- NamesDefaults
- PatternTypers
- RefChecks
- StdAttachments
- StructuredTypeStrings
- SuperAccessors
- SyntheticMethods
- Tags
- TreeCheckers
- TypeDiagnostics
- TypeStrings
- Typers
- TypersStats
- TypersTracking
- Unapplies

t

scala.tools.nsc.typechecker

# Contexts

###

#### trait Contexts extends AnyRef

Self Type
  Analyzer
Source
  Contexts.scala

Linear Supertypes
AnyRef, Any
Known Subclasses
erasure, treeChecker, ScaladocAnalyzer, InteractiveAnalyzer, Erasure, Duplicator, SpecializationDuplicator, Analyzer, Duplicators, TreeCheckers
Type Hierarchy

Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. Contexts
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.  class Context extends AnyRef

   A motley collection of the state and loosely associated behaviour of the type checker.

   A motley collection of the state and loosely associated behaviour of the type checker. Each `Typer` has an associated context, and as it descends into the tree new `(Typer, Context)` pairs are spawned.

   Meet the crew; first the state:

   - A tree, symbol, and scope representing the focus of the typechecker
   - An enclosing context, `outer`.
   - The current compilation unit.
   - A variety of bits that track the current error reporting policy (more on this later); whether or not implicits/macros are enabled, whether we are in a self or super call or in a constructor suffix. These are represented as bits in the mask `contextMode`.
   - Some odds and ends: undetermined type parameters of the current line of type inference; contextual augmentation for error messages, tracking of the nesting depth.

   And behaviour:

   - The central point for issuing errors and warnings from the typechecker, with a means to buffer these for use in 'silent' type checking, when some recovery might be possible.
   - `Context` is something of a Zipper for the tree were are typechecking: it `enclosingContextChain` is the path back to the root. This is exactly what we need to resolve names (`lookupSymbol`) and to collect in-scope implicit definitions (`implicitss`) Supporting these are `imports`, which represents all `Import` trees in in the enclosing context chain.
   - In a similar vein, we can assess accessibility (`isAccessible`.)

   More on error buffering: When are type errors recoverable? In quite a few places, it turns out. Some examples: trying to type an application with/without the expected type, or with/without implicit views enabled. This is usually mediated by `Typer.silent`, `Inferencer#tryTwice`.

   Initially, starting from the `typer` phase, the contexts either buffer or report errors; afterwards errors are thrown. This is configured in `rootContext`. Additionally, more fine grained control is needed based on the kind of error; ambiguity errors are often suppressed during exploratory typing, such as determining whether `a == b` in an argument position is an assignment or a named argument, when `Inferencer#isApplicableSafe` type checks applications with and without an expected type, or when `Typer#tryTypedApply` tries to fit arguments to a function type with/without implicit views.

   When the error policies entail error/warning buffering, the mutable ContextReporter records everything that is issued. It is important to note, that child Contexts created with `make` "inherit" the very same `ContextReporter` instance, whereas children spawned through `makeSilent` receive a separate, fresh buffer.

2.  abstract class ContextReporter extends AnyRef

   A reporter for use during type checking.

   A reporter for use during type checking. It has multiple modes for handling errors.

   The default (immediate mode) is to send the error to the global reporter. When switched into buffering mode via makeBuffering, errors and warnings are buffered and not be reported (there's a special case for ambiguity errors for some reason: those are force to the reporter when context.ambiguousErrors, or else they are buffered -- TODO: can we simplify this?)

   When using the type checker after typers, an error results in a TypeError being thrown. TODO: get rid of this mode.

   To handle nested contexts, reporters share buffers. TODO: only buffer in BufferingReporter, emit immediately in ImmediateReporter

3.  final class ImportContext extends Analyzer.Context

   A `Context` focussed on an `Import` tree

4.  class ImportInfo extends AnyRef
5.  type ImportType = Global.ImportType

### 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 Contexts toany2stringadd[Contexts] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd
4.  def ->[B](y: B): (Contexts, B)
   Implicit
     This member is added by an implicit conversion from Contexts toArrowAssoc[Contexts] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()
5.  final def ==(arg0: Any): Boolean
   Definition Classes
     AnyRef → Any
6.  val ImportType: Global.ImportType.type
7.  def ambiguousDefinitions(owner: Global.Symbol, other: Global.Symbol): Global.LookupAmbiguous
8.  def ambiguousDefnAndImport(owner: Global.Symbol, imp: Analyzer.ImportInfo): Global.LookupAmbiguous
9.  def ambiguousImports(imp1: Analyzer.ImportInfo, imp2: Analyzer.ImportInfo): Global.LookupAmbiguous
10.  final def asInstanceOf[T0]: T0
    Definition Classes
      Any
11.  def clone(): AnyRef
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.CloneNotSupportedException]) @native()
12.  def ensuring(cond: (Contexts) => Boolean, msg: => Any): Contexts
    Implicit
      This member is added by an implicit conversion from Contexts toEnsuring[Contexts] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
13.  def ensuring(cond: (Contexts) => Boolean): Contexts
    Implicit
      This member is added by an implicit conversion from Contexts toEnsuring[Contexts] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
14.  def ensuring(cond: Boolean, msg: => Any): Contexts
    Implicit
      This member is added by an implicit conversion from Contexts toEnsuring[Contexts] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
15.  def ensuring(cond: Boolean): Contexts
    Implicit
      This member is added by an implicit conversion from Contexts toEnsuring[Contexts] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
16.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
17.  def equals(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef → Any
18.  val excludedRootImportsCached: HashMap[Global.CompilationUnit, List[Global.Symbol]]
19.  def finalize(): Unit
    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.Throwable])
20.  def formatted(fmtstr: String): String
    Implicit
      This member is added by an implicit conversion from Contexts toStringFormat[Contexts] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()
21.  final def getClass(): Class[_ <: AnyRef]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
22.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
23.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
24.  val lastAccessCheckDetails: String
25.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
26.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
27.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
28.  def onTreeCheckerError(pos: Global.Position, msg: String): Unit
    Attributes
      protected
29.  def registerImport(ctx: Analyzer.Context, imp: Global.Import): Unit
30.  def resetContexts(): Unit
31.  def rootContext(unit: Global.CompilationUnit, tree: Global.Tree = EmptyTree, throwing: Boolean = false, checking: Boolean = false): Analyzer.Context
32.  def rootContextPostTyper(unit: Global.CompilationUnit, tree: Global.Tree = EmptyTree): Analyzer.Context
33.  def rootImports(unit: Global.CompilationUnit): List[Global.Symbol]

    List of symbols to import from in a root context.

    List of symbols to import from in a root context. By default, that is `java.lang`, `scala`, and scala.Predef, in that order.

    - if option `-Yimports` is supplied, then that specifies the preamble imports
    - if the unit body has an import of Predef among its leading imports, or if the tree is scala.Predef, `Predef` is not imported. Similarly for any module among the preamble imports.
    - if the unit is java defined, only `java.lang` is imported

    The root imports for a unit are cached.

    Attributes
      protected
34.  val rootImportsCached: HashMap[Global.CompilationUnit, List[Global.Symbol]]
35.  final def synchronized[T0](arg0: => T0): T0
    Definition Classes
      AnyRef
36.  def toString(): String
    Definition Classes
      AnyRef → Any
37.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
38.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException])
39.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws(classOf[java.lang.InterruptedException]) @native()
40.  def warnUnusedImports(unit: Global.CompilationUnit): Unit
41.  object NoContext extends Analyzer.Context

### Deprecated Value Members

1.  def →[B](y: B): (Contexts, B)
   Implicit
     This member is added by an implicit conversion from Contexts toArrowAssoc[Contexts] 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 fromContexts to any2stringadd[Contexts]

### Inherited by implicit conversion StringFormat fromContexts to StringFormat[Contexts]

### Inherited by implicit conversion Ensuring fromContexts to Ensuring[Contexts]

### Inherited by implicit conversion ArrowAssoc fromContexts to ArrowAssoc[Contexts]

### Ungrouped