Scala Compiler2.12.7 < 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
- 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
Version

  1.0

Linear Supertypes
AnyRef, Any
Known Subclasses
erasure, treeChecker, ScaladocAnalyzer, InteractiveAnalyzer, Erasure, Duplicator, SpecializationDuplicator, Analyzer, Duplicators, TreeCheckers
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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

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Visibility

1. Public
2. All

### 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 ReportBuffer records everything that is issued. It is important to note, that child Contexts created with `make` "inherit" the very same `ReportBuffer` instance, whereas children spawned through `makeSilent` receive a separate, fresh buffer.

2.  abstract class ContextReporter extends Reporter

   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.  trait 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 to any2stringadd[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 to ArrowAssoc[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 ambiguousDefnAndImport(owner: Global.Symbol, imp: Analyzer.ImportInfo): Global.LookupAmbiguous
8.  def ambiguousImports(imp1: Analyzer.ImportInfo, imp2: Analyzer.ImportInfo): Global.LookupAmbiguous
9.  final def asInstanceOf[T0]: T0
   Definition Classes
     Any
10.  def clone(): AnyRef
    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @native() @throws( ... )
11.  def ensuring(cond: (Contexts) ⇒ Boolean, msg: ⇒ Any): Contexts
    Implicit
      This member is added by an implicit conversion from Contexts to Ensuring[Contexts] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
12.  def ensuring(cond: (Contexts) ⇒ Boolean): Contexts
    Implicit
      This member is added by an implicit conversion from Contexts to Ensuring[Contexts] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
13.  def ensuring(cond: Boolean, msg: ⇒ Any): Contexts
    Implicit
      This member is added by an implicit conversion from Contexts to Ensuring[Contexts] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
14.  def ensuring(cond: Boolean): Contexts
    Implicit
      This member is added by an implicit conversion from Contexts to Ensuring[Contexts] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
15.  final def eq(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
16.  def equals(arg0: Any): Boolean
    Definition Classes
      AnyRef → Any
17.  def finalize(): Unit
    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )
18.  def formatted(fmtstr: String): String
    Implicit
      This member is added by an implicit conversion from Contexts to StringFormat[Contexts] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()
19.  final def getClass(): Class[_]
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
20.  def hashCode(): Int
    Definition Classes
      AnyRef → Any
    Annotations
      @native()
21.  def isIndividualImport(s: Global.ImportSelector): Boolean
22.  final def isInstanceOf[T0]: Boolean
    Definition Classes
      Any
23.  def isMaskImport(s: Global.ImportSelector): Boolean
24.  def isWildcardImport(s: Global.ImportSelector): Boolean
25.  val lastAccessCheckDetails: String
26.  final def ne(arg0: AnyRef): Boolean
    Definition Classes
      AnyRef
27.  final def notify(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
28.  final def notifyAll(): Unit
    Definition Classes
      AnyRef
    Annotations
      @native()
29.  def onTreeCheckerError(pos: Global.Position, msg: String): Unit
    Attributes
      protected
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. Typically that is `java.lang`, `scala`, and scala.Predef, in that order. Exceptions:

    - if option `-Yno-imports` is given, nothing is imported
    - if the unit is java defined, only `java.lang` is imported
    - if option `-Yno-predef` is given, if the unit body has an import of Predef among its leading imports, or if the tree is scala.Predef, `Predef` is not imported.
    Attributes
      protected
34.  final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
      AnyRef
35.  def toString(): String
    Definition Classes
      AnyRef → Any
36.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
37.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
38.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @native() @throws( ... )
39.  def warnUnusedImports(unit: Global.CompilationUnit): Unit
40.  def →[B](y: B): (Contexts, B)
    Implicit
      This member is added by an implicit conversion from Contexts to ArrowAssoc[Contexts] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc
41.  object NoContext extends Analyzer.Context

### Inherited from AnyRef

### Inherited from Any

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

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

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

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

### Ungrouped