Packages

class Context extends AnyRef

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.

Source
Contexts.scala
Linear Supertypes
AnyRef, Any
Known Subclasses
ImportContext, NoContext
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  1. Context
  2. AnyRef
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Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Type Members

  1. abstract class TryTwice extends AnyRef

    Try inference twice: once without views and once with views, unless views are already disabled.

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 Analyzer.Context to any2stringadd[Analyzer.Context] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (Analyzer.Context, B)
    Implicit
    This member is added by an implicit conversion from Analyzer.Context to ArrowAssoc[Analyzer.Context] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  6. def ambiguousErrors: Boolean
  7. def apply(mask: ContextMode): Boolean

    Is this context in all modes in the given mask?

  8. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  9. def bufferErrors: Boolean
  10. def clone(): AnyRef
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  11. var contextMode: ContextMode

    A bitmask containing all the boolean flags in a context, e.g.

    A bitmask containing all the boolean flags in a context, e.g. are implicit views enabled

  12. def defaultModeForTyped: Mode
  13. def deprecationWarning(pos: Global.Position, sym: Global.Symbol): Unit
  14. def deprecationWarning(pos: Global.Position, sym: Global.Symbol, msg: String, since: String): Unit
  15. val depth: Int
  16. var diagUsedDefaults: Boolean

    To enrich error messages involving default arguments.

    To enrich error messages involving default arguments. When extending the notion, group diagnostics in an object.

  17. def echo(pos: Global.Position, msg: String): Unit
  18. var enclClass: Analyzer.Context

    The next outer context whose tree is a template or package definition

  19. def enclClassOrMethod: Analyzer.Context

    The next enclosing context (potentially this) that is owned by a class or method

  20. var enclMethod: Analyzer.Context

    The next outer context whose tree is a method

  21. def enclosingApply: Analyzer.Context

    ...or an Apply.

  22. def enclosingCaseDef: Analyzer.Context

    The next enclosing context (potentially this) that has a CaseDef as a tree

  23. def enclosingContextChain: List[Analyzer.Context]
  24. def enclosingNonImportContext: Analyzer.Context
  25. def enclosingSubClassContext(clazz: Global.Symbol): Analyzer.Context

    Return the closest enclosing context that defines a subclass of clazz or a companion object thereof, or NoContext if no such context exists.

  26. def enrichmentEnabled: Boolean
  27. def enrichmentEnabled_=(value: Boolean): Unit
  28. def ensuring(cond: (Analyzer.Context) ⇒ Boolean, msg: ⇒ Any): Analyzer.Context
    Implicit
    This member is added by an implicit conversion from Analyzer.Context to Ensuring[Analyzer.Context] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  29. def ensuring(cond: (Analyzer.Context) ⇒ Boolean): Analyzer.Context
    Implicit
    This member is added by an implicit conversion from Analyzer.Context to Ensuring[Analyzer.Context] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  30. def ensuring(cond: Boolean, msg: ⇒ Any): Analyzer.Context
    Implicit
    This member is added by an implicit conversion from Analyzer.Context to Ensuring[Analyzer.Context] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  31. def ensuring(cond: Boolean): Analyzer.Context
    Implicit
    This member is added by an implicit conversion from Analyzer.Context to Ensuring[Analyzer.Context] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  32. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  33. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  34. def error(pos: Global.Position, msg: String): Unit

    Issue/throw the given error message according to the current mode for error reporting.

  35. def extractUndetparams(): List[Global.Symbol]

    Return and clear the undetermined type parameters

  36. def featureWarning(pos: Global.Position, featureName: String, featureDesc: String, featureTrait: Global.Symbol, construct: ⇒ String = "", required: Boolean): Unit
  37. def finalize(): Unit
    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  38. def firstImport: Option[Analyzer.ImportInfo]

    Equivalent to imports.headOption, but more efficient

  39. def fixPosition(pos: Global.Position): Global.Position
  40. def formatted(fmtstr: String): String
    Implicit
    This member is added by an implicit conversion from Analyzer.Context to StringFormat[Analyzer.Context] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  41. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
  42. def hashCode(): Int
    Definition Classes
    AnyRef → Any
  43. def implicitsEnabled: Boolean
  44. def implicitsEnabled_=(value: Boolean): Unit
  45. def implicitss: List[List[Analyzer.ImplicitInfo]]
  46. def imports: List[Analyzer.ImportInfo]

    The currently visible imports

  47. def inConstructorSuffix: Boolean
  48. def inConstructorSuffix_=(value: Boolean): Unit
  49. def inPatAlternative: Boolean
  50. def inPatAlternative_=(value: Boolean): Unit
  51. def inReturnExpr: Boolean
  52. def inSecondTry: Boolean
  53. def inSecondTry_=(value: Boolean): Unit
  54. def inSelfSuperCall: Boolean
  55. def inSelfSuperCall_=(value: Boolean): Unit
  56. final def inSilentMode(expr: ⇒ Boolean): Boolean
    Annotations
    @inline()
  57. def inSuperInit: Boolean
  58. def inSuperInit_=(value: Boolean): Unit
  59. def inTypeConstructorAllowed: Boolean
  60. def initRootContext(throwing: Boolean = false, checking: Boolean = false): Unit

    Use reporter (possibly buffered) for errors/warnings and enable implicit conversion *

  61. def isAccessible(sym: Global.Symbol, pre: Global.Type, superAccess: Boolean = false): Boolean

    Is sym accessible as a member of pre in current context?

  62. def isInPackageObject(sym: Global.Symbol, pkg: Global.Symbol): Boolean

    Must sym defined in package object of package pkg, if it selected from a prefix with pkg as its type symbol?

  63. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  64. def isNameInScope(name: Global.Name): Boolean
  65. def isRootImport: Boolean
  66. final def isSearchingForImplicitParam: Boolean
  67. def lookup(name: Global.Name, expectedOwner: Global.Symbol): Global.Symbol

    Find a symbol in this context or one of its outers.

    Find a symbol in this context or one of its outers.

    Used to find symbols are owned by methods (or fields), they can't be found in some scope.

    Examples: companion module of classes owned by a method, default getter methods of nested methods. See NamesDefaults.scala

  68. final def lookupCompanionInIncompleteOwner(original: Global.Symbol): Global.Symbol
  69. def lookupSymbol(name: Global.Name, qualifies: (Global.Symbol) ⇒ Boolean): Global.NameLookup

    Find the symbol of a simple name starting from this context.

    Find the symbol of a simple name starting from this context. All names are filtered through the "qualifies" predicate, the search continuing as long as no qualifying name is found.

  70. def macrosEnabled: Boolean
  71. def macrosEnabled_=(value: Boolean): Unit
  72. def make(tree: Global.Tree, owner: Global.Symbol, scope: Global.Scope): Analyzer.Context
  73. def make(tree: Global.Tree = tree, owner: Global.Symbol = owner, scope: Global.Scope = scope, unit: Global.CompilationUnit = unit, reporter: Analyzer.ContextReporter = this.reporter): Analyzer.Context

    Construct a child context.

    Construct a child context. The parent and child will share the report buffer. Compare with makeSilent, in which the child has a fresh report buffer.

    If tree is an Import, that import will be available at the head of Context#imports.

  74. def makeConstructorContext: Analyzer.Context

    A context for typing constructor parameter ValDefs, super or self invocation arguments and default getters of constructors.

    A context for typing constructor parameter ValDefs, super or self invocation arguments and default getters of constructors. These expressions need to be type checked in a scope outside the class, cf. spec 5.3.1.

    This method is called by namer / typer where this is the context for the constructor DefDef. The owner of the resulting (new) context is the outer context for the Template, i.e. the context for the ClassDef. This means that class type parameters will be in scope. The value parameters of the current constructor are also entered into the new constructor scope. Members of the class however will not be accessible.

  75. def makeImplicit(reportAmbiguousErrors: Boolean): Analyzer.Context

    Make a silent child context does not allow implicits.

    Make a silent child context does not allow implicits. Used to prevent chaining of implicit views.

  76. def makeNewScope(tree: Global.Tree, owner: Global.Symbol, reporter: Analyzer.ContextReporter = this.reporter): Analyzer.Context

    Make a child context that represents a new nested scope

  77. def makeNonSilent(newtree: Global.Tree): Analyzer.Context
  78. def makeSilent(reportAmbiguousErrors: Boolean = ambiguousErrors, newtree: Global.Tree = tree): Analyzer.Context

    Make a child context that buffers errors and warnings into a fresh report buffer.

  79. var namedApplyBlockInfo: Option[(Global.Tree, Analyzer.NamedApplyInfo)]
  80. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  81. def nextEnclosing(p: (Analyzer.Context) ⇒ Boolean): Analyzer.Context
  82. final def notify(): Unit
    Definition Classes
    AnyRef
  83. final def notifyAll(): Unit
    Definition Classes
    AnyRef
  84. var openImplicits: List[Analyzer.OpenImplicit]

    Types for which implicit arguments are currently searched

  85. final def outer: Analyzer.Context
  86. def outerDepth: Int
    Attributes
    protected
  87. val owner: Global.Symbol
  88. var prefix: Global.Type
  89. def pushTypeBounds(sym: Global.Symbol): Unit
  90. def reportErrors: Boolean
  91. def reporter: Analyzer.ContextReporter
  92. def resetCache(): Unit
  93. def restoreTypeBounds(tp: Global.Type): Global.Type
  94. def returnsSeen: Boolean
  95. def returnsSeen_=(value: Boolean): Unit
  96. def retyping: Boolean
  97. def retyping_=(value: Boolean): Unit
  98. var savedTypeBounds: List[(Global.Symbol, Global.Type)]

    Saved type bounds for type parameters which are narrowed in a GADT.

  99. def savingUndeterminedTypeParams[A](reportAmbiguous: Boolean = ambiguousErrors)(body: ⇒ A): A

    Run body with this context with no undetermined type parameters, restore the original the original list afterwards.

    Run body with this context with no undetermined type parameters, restore the original the original list afterwards.

    reportAmbiguous

    Should ambiguous errors be reported during evaluation of body?

  100. val scope: Global.Scope
  101. def set(enable: ContextMode = NOmode, disable: ContextMode = NOmode): Context.this.type

    Set all modes in the mask enable to true, and all in disable to false.

  102. def siteString: String
  103. def starPatterns: Boolean
  104. def starPatterns_=(value: Boolean): Unit
  105. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  106. def toString(): String
    Definition Classes
    Context → AnyRef → Any
  107. val tree: Global.Tree
  108. def undetparams: List[Global.Symbol]

    Undetermined type parameters.

    Undetermined type parameters. See Infer#{inferExprInstance, adjustTypeArgs}. Not inherited to child contexts

  109. def undetparamsString: String
  110. def undetparams_=(ps: List[Global.Symbol]): Unit
  111. val unit: Global.CompilationUnit
  112. def update(mask: ContextMode, value: Boolean): Unit

    Update all modes in mask to value

  113. var variance: Variance

    Variance relative to enclosing class

  114. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  115. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  116. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  117. def warning(pos: Global.Position, msg: String): Unit

    Issue/throw the given error message according to the current mode for error reporting.

  118. final def withImplicits[T](enabled: Boolean)(op: ⇒ T): T
    Annotations
    @inline()
  119. final def withImplicitsDisabled[T](op: ⇒ T): T
    Annotations
    @inline()
  120. final def withImplicitsDisabledAllowEnrichment[T](op: ⇒ T): T
    Annotations
    @inline()
  121. final def withImplicitsEnabled[T](op: ⇒ T): T
    Annotations
    @inline()
  122. final def withMacros[T](enabled: Boolean)(op: ⇒ T): T
    Annotations
    @inline()
  123. final def withMacrosDisabled[T](op: ⇒ T): T
    Annotations
    @inline()
  124. final def withMacrosEnabled[T](op: ⇒ T): T
    Annotations
    @inline()
  125. final def withMode[T](enabled: ContextMode = NOmode, disabled: ContextMode = NOmode)(op: ⇒ T): T
    Annotations
    @inline()
  126. final def withOnlyStickyModes[T](op: ⇒ T): T
    Annotations
    @inline()
  127. final def withinPatAlternative[T](op: ⇒ T): T
    Annotations
    @inline()
  128. final def withinReturnExpr[T](op: ⇒ T): T
    Annotations
    @inline()
  129. final def withinSecondTry[T](op: ⇒ T): T
    Annotations
    @inline()
  130. final def withinStarPatterns[T](op: ⇒ T): T
    Annotations
    @inline()
  131. final def withinSuperInit[T](op: ⇒ T): T
    Annotations
    @inline()
  132. final def withinTypeConstructorAllowed[T](op: ⇒ T): T

    TypeConstructorAllowed is enabled when we are typing a higher-kinded type.

    TypeConstructorAllowed is enabled when we are typing a higher-kinded type. adapt should then check kind-arity based on the prototypical type's kind arity. Type arguments should not be inferred.

    Annotations
    @inline()
  133. def →[B](y: B): (Analyzer.Context, B)
    Implicit
    This member is added by an implicit conversion from Analyzer.Context to ArrowAssoc[Analyzer.Context] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from Analyzer.Context to any2stringadd[Analyzer.Context]

Inherited by implicit conversion StringFormat from Analyzer.Context to StringFormat[Analyzer.Context]

Inherited by implicit conversion Ensuring from Analyzer.Context to Ensuring[Analyzer.Context]

Inherited by implicit conversion ArrowAssoc from Analyzer.Context to ArrowAssoc[Analyzer.Context]

Ungrouped