scala.tools.nsc.typechecker

# Contexts

#### trait Contexts extends AnyRef

Self Type
  Analyzer
Source
  Contexts.scala
Version

  1.0

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

1. Contexts
2. AnyRef
3. Any

Implicitly

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

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### 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 pararameters 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 defintions (`implicitss`) Supporting these are `imports`, which represents all `Import` trees in in the enclosing context chain.
   - In a similar vein, we can assess accessiblity (`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`.

   Intially, 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 exploraratory typing, such as determining whether `a == b` in an argument position is an assignment or a named argument, when `Infererencer#isApplicableSafe` type checks applications with and without an expected type, or whtn `Typer#tryTypedApply` tries to fit arguments to a function type with/without implicit views.

   When the error policies entails 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 an separate, fresh buffer.

2. #### trait ImportContext extends Analyzer.Context

   A `Context` focussed on an `Import` tree

3. #### class ImportInfo extends AnyRef

4. #### type ImportType = Global.ImportType

5. #### final class ReportBuffer extends AnyRef

   A buffer for warnings and errors that are accumulated during speculative type checking.

### 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 information
     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 information
     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. #### object NoContext extends Analyzer.Context

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[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

12. #### def ensuring(cond: (Contexts) ⇒ Boolean, msg: ⇒ Any): Contexts

    Implicit information
      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: (Contexts) ⇒ Boolean): Contexts

    Implicit information
      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, msg: ⇒ Any): Contexts

    Implicit information
      This member is added by an implicit conversion from Contexts to Ensuring[Contexts] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring

15. #### def ensuring(cond: Boolean): Contexts

    Implicit information
      This member is added by an implicit conversion from Contexts to Ensuring[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: Any): Boolean

    Definition Classes
      AnyRef → Any

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

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )

19. #### def formatted(fmtstr: String): String

    Implicit information
      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()

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

    Definition Classes
      AnyRef → Any

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

    Definition Classes
      AnyRef → Any

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

    Definition Classes
      Any

23. #### var lastAccessCheckDetails: String

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

    Definition Classes
      AnyRef

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

    Definition Classes
      AnyRef

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

    Definition Classes
      AnyRef

27. #### def onTreeCheckerError(pos: Global.Position, msg: String): Unit

    Attributes
      protected

28. #### def resetContexts(): Unit

29. #### def rootContext(unit: Global.CompilationUnit, tree: Global.Tree = EmptyTree, erasedTypes: Boolean = false): Analyzer.Context

30. #### 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

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

    Definition Classes
      AnyRef

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

    Definition Classes
      AnyRef → Any

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

36. #### def warnUnusedImports(unit: Global.CompilationUnit): Unit

37. #### def →[B](y: B): (Contexts, B)

    Implicit information
      This member is added by an implicit conversion from Contexts to ArrowAssoc[Contexts] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc

### 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