scala.tools.nsc.transform.patmat.MatchApproximation

# MatchApproximator

#### trait MatchApproximator extends TreeMakers with TreesAndTypesDomain

Represent a match as a formula in propositional logic that encodes whether the match matches (abstractly: we only consider types)

Source
  MatchAnalysis.scala

Linear Supertypes
MatchApproximation.TreesAndTypesDomain, MatchApproximation.CheckableTreeAndTypeAnalysis, MatchApproximation.PropositionalLogic, MatchApproximation.TreeMakers, MatchApproximation.CodegenCore, MatchApproximation.TypedSubstitution, MatchApproximation.MatchMonadInterface, AnyRef, Any
Known Subclasses
CommonSubconditionElimination, MatchAnalyzer, MatchOptimizer, OptimizingMatchTranslator
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Inherited

1. MatchApproximator
2. TreesAndTypesDomain
3. CheckableTreeAndTypeAnalysis
4. PropositionalLogic
5. TreeMakers
6. CodegenCore
7. TypedSubstitution
8. MatchMonadInterface
9. AnyRef
10. Any

Implicitly

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

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### Type Members

1. #### trait AbsCodegen extends AnyRef

   Definition Classes
     CodegenCore

2. #### trait AbsVar extends AnyRef

   Definition Classes
     PropositionalLogic

3. #### case class AlternativesTreeMaker(prevBinder: Global.Symbol, altss: List[List[TreeMaker]], pos: Global.Position) extends TreeMaker with NoNewBinders with Product with Serializable

   Definition Classes
     TreeMakers

4. #### case class And(a: Prop, b: Prop) extends Prop with Product with Serializable

   Definition Classes
     PropositionalLogic

5. #### case class BodyTreeMaker(body: Global.Tree, matchPt: Global.Type) extends TreeMaker with NoNewBinders with Product with Serializable

   Definition Classes
     TreeMakers

6. #### trait Casegen extends AbsCodegen

   Definition Classes
     CodegenCore

7. #### abstract class CommonCodegen extends AbsCodegen

   Definition Classes
     CodegenCore

8. #### sealed abstract class CondTreeMaker extends FunTreeMaker

   Definition Classes
     TreeMakers

9. #### sealed abstract class Const extends AnyRef

   Definition Classes
     TreesAndTypesDomain

10. #### case class Eq(p: Var, q: Const) extends Prop with Product with Serializable

    Definition Classes
      PropositionalLogic

11. #### case class EqualityTestTreeMaker(prevBinder: Global.Symbol, patTree: Global.Tree, pos: Global.Position) extends CondTreeMaker with Product with Serializable

    Definition Classes
      TreeMakers

12. #### case class ExtractorTreeMaker(extractor: Global.Tree, extraCond: Option[Global.Tree], nextBinder: Global.Symbol)(subPatBinders: List[Global.Symbol], subPatRefs: List[Global.Tree], extractorReturnsBoolean: Boolean, checkedLength: Option[Int], prevBinder: Global.Symbol, ignoredSubPatBinders: Set[Global.Symbol]) extends FunTreeMaker with PreserveSubPatBinders with Product with Serializable

    Make a TreeMaker that will result in an extractor call specified by `extractor` the next TreeMaker (here, we don't know which it'll be) is chained after this one by flatMap'ing a function with binder `nextBinder` over our extractor's result the function's body is determined by the next TreeMaker (furthermore, the interpretation of `flatMap` depends on the codegen instance we're using).

    Make a TreeMaker that will result in an extractor call specified by `extractor` the next TreeMaker (here, we don't know which it'll be) is chained after this one by flatMap'ing a function with binder `nextBinder` over our extractor's result the function's body is determined by the next TreeMaker (furthermore, the interpretation of `flatMap` depends on the codegen instance we're using).

    The values for the subpatterns, as computed by the extractor call in `extractor`, are stored in local variables that re-use the symbols in `subPatBinders`. This makes extractor patterns more debuggable (SI-5739).

    Definition Classes
      TreeMakers

13. #### abstract type Formula

    Definition Classes
      PropositionalLogic

14. #### abstract type FormulaBuilder

    Definition Classes
      PropositionalLogic

15. #### sealed abstract class FunTreeMaker extends TreeMaker

    Definition Classes
      TreeMakers

16. #### case class GuardTreeMaker(guardTree: Global.Tree) extends TreeMaker with NoNewBinders with Product with Serializable

    Definition Classes
      TreeMakers

17. #### type Model = Map[Sym, Boolean]

    Definition Classes
      PropositionalLogic

18. #### sealed trait NoNewBinders extends TreeMaker

    Definition Classes
      TreeMakers

19. #### case class Not(a: Prop) extends Prop with Product with Serializable

    Definition Classes
      PropositionalLogic

20. #### case class Or(a: Prop, b: Prop) extends Prop with Product with Serializable

    Definition Classes
      PropositionalLogic

21. #### sealed trait PreserveSubPatBinders extends TreeMaker

    Definition Classes
      TreeMakers

22. #### case class ProductExtractorTreeMaker(prevBinder: Global.Symbol, extraCond: Option[Global.Tree])(subPatBinders: List[Global.Symbol], subPatRefs: List[Global.Tree], mutableBinders: List[Global.Symbol], binderKnownNonNull: Boolean, ignoredSubPatBinders: Set[Global.Symbol]) extends FunTreeMaker with PreserveSubPatBinders with Product with Serializable

    An optimized version of ExtractorTreeMaker for Products.

    An optimized version of ExtractorTreeMaker for Products. For now, this is hard-coded to case classes, and we simply extract the case class fields.

    The values for the subpatterns, as specified by the case class fields at the time of extraction, are stored in local variables that re-use the symbols in `subPatBinders`. This makes extractor patterns more debuggable (SI-5739) as well as avoiding mutation after the pattern has been matched (SI-5158, SI-6070)

    TODO: make this user-definable as follows When a companion object defines a method `def unapply_1(x: T): U_1`, but no `def unapply` or `def unapplySeq`, the extractor is considered to match any non-null value of type T the pattern is expected to have as many sub-patterns as there are `def unapply_I(x: T): U_I` methods, and the type of the I'th sub-pattern is `U_I`. The same exception for Seq patterns applies: if the last extractor is of type `Seq[U_N]`, the pattern must have at least N arguments (exactly N if the last argument is annotated with `: _*`). The arguments starting at N (and beyond) are taken from the sequence returned by apply_N, and it is checked that that sequence has enough elements to provide values for all expected sub-patterns.

    For a case class C, the implementation is assumed to be `def unapply_I(x: C) = x._I`, and the extractor call is inlined under that assumption.

    Definition Classes
      TreeMakers

23. #### class Prop extends AnyRef

    Definition Classes
      PropositionalLogic

24. #### trait PropMap extends AnyRef

    Definition Classes
      PropositionalLogic

25. #### trait PropTraverser extends AnyRef

    Definition Classes
      PropositionalLogic

26. #### case class SubstOnlyTreeMaker(prevBinder: Global.Symbol, nextBinder: Global.Symbol) extends TreeMaker with Product with Serializable

    Definition Classes
      TreeMakers

27. #### class Substitution extends AnyRef

    Definition Classes
      TypedSubstitution

28. #### abstract case class Sym(variable: Var, const: Const) extends Prop with Product with Serializable

    Definition Classes
      PropositionalLogic

29. #### case class Test(prop: MatchApproximator.Prop, treeMaker: MatchApproximator.TreeMaker) extends Product with Serializable

30. #### type Tree = Global.Tree

    Definition Classes
      TreesAndTypesDomain → PropositionalLogic

31. #### abstract class TreeMaker extends AnyRef

    Definition Classes
      TreeMakers

32. #### class TreeMakersToProps extends AnyRef

33. #### class TreeMakersToPropsIgnoreNullChecks extends TreeMakersToProps

34. #### case class TrivialTreeMaker(tree: Global.Tree) extends TreeMaker with NoNewBinders with Product with Serializable

    Definition Classes
      TreeMakers

35. #### type Type = Global.Type

    Definition Classes
      TreesAndTypesDomain → PropositionalLogic

36. #### sealed class TypeConst extends Const

    Definition Classes
      TreesAndTypesDomain

37. #### trait TypeConstExtractor extends AnyRef

    Definition Classes
      PropositionalLogic

38. #### case class TypeTestTreeMaker(prevBinder: Global.Symbol, testedBinder: Global.Symbol, expectedTp: Global.Type, nextBinderTp: Global.Type)(pos: Global.Position, extractorArgTypeTest: Boolean = false) extends CondTreeMaker with Product with Serializable

    implements the run-time aspects of (§8.2) (typedPattern has already done the necessary type transformations)

    implements the run-time aspects of (§8.2) (typedPattern has already done the necessary type transformations)

    Type patterns consist of types, type variables, and wildcards. A type pattern T is of one of the following forms:

    - A reference to a class C, p.C, or T#C. This type pattern matches any non-null instance of the given class. Note that the prefix of the class, if it is given, is relevant for determining class instances. For instance, the pattern p.C matches only instances of classes C which were created with the path p as prefix. The bottom types scala.Nothing and scala.Null cannot be used as type patterns, because they would match nothing in any case.
    - A singleton type p.type. This type pattern matches only the value denoted by the path p (that is, a pattern match involved a comparison of the matched value with p using method eq in class AnyRef). // TODO: the actual pattern matcher uses ==, so that's what I'm using for now // https://issues.scala-lang.org/browse/SI-4577 "pattern matcher, still disappointing us at equality time"
    - A compound type pattern T1 with ... with Tn where each Ti is a type pat- tern. This type pattern matches all values that are matched by each of the type patterns Ti.
    - A parameterized type pattern T[a1,...,an], where the ai are type variable patterns or wildcards _. This type pattern matches all values which match T for some arbitrary instantiation of the type variables and wildcards. The bounds or alias type of these type variable are determined as described in (§8.3).
    - A parameterized type pattern scala.Array[T1], where T1 is a type pattern. // TODO This type pattern matches any non-null instance of type scala.Array[U1], where U1 is a type matched by T1.
    Definition Classes
      TreeMakers

39. #### class UniqueSym extends Sym

    Definition Classes
      PropositionalLogic

40. #### sealed class ValueConst extends Const

    Definition Classes
      TreesAndTypesDomain

41. #### trait ValueConstExtractor extends AnyRef

    Definition Classes
      PropositionalLogic

42. #### class Var extends AbsVar

    Definition Classes
      TreesAndTypesDomain

43. #### trait VarExtractor extends AnyRef

    Definition Classes
      PropositionalLogic

### Abstract Value Members

1. #### abstract val EmptyModel: Model

   Definition Classes
     PropositionalLogic

2. #### abstract val NoModel: Model

   Definition Classes
     PropositionalLogic

3. #### abstract def addFormula(buff: FormulaBuilder, f: Formula): Unit

   Definition Classes
     PropositionalLogic

4. #### abstract def analyzeCases(prevBinder: Global.Symbol, cases: List[List[TreeMaker]], pt: Global.Type, suppression: MatchApproximation.Suppression): Unit

   Definition Classes
     TreeMakers

5. #### abstract def andFormula(a: Formula, b: Formula): Formula

   Definition Classes
     PropositionalLogic

6. #### abstract def cnfString(f: Formula): String

   Definition Classes
     PropositionalLogic

7. #### abstract def codegen: AbsCodegen

   Definition Classes
     CodegenCore

8. #### abstract def eqFreePropToSolvable(p: Prop): Formula

   Definition Classes
     PropositionalLogic

9. #### abstract def findAllModelsFor(f: Formula): List[Model]

   Definition Classes
     PropositionalLogic

10. #### abstract def findModelFor(f: Formula): Model

    Definition Classes
      PropositionalLogic

11. #### abstract def formulaBuilder: FormulaBuilder

    Definition Classes
      PropositionalLogic

12. #### abstract def optimizeCases(prevBinder: Global.Symbol, cases: List[List[TreeMaker]], pt: Global.Type): (List[List[TreeMaker]], List[Global.Tree])

    Definition Classes
      TreeMakers

13. #### abstract def reportWarning(message: String): Unit

    Definition Classes
      PropositionalLogic

14. #### abstract def simplifyFormula(a: Formula): Formula

    Definition Classes
      PropositionalLogic

15. #### abstract def toFormula(buff: FormulaBuilder): Formula

    Definition Classes
      PropositionalLogic

16. #### abstract val typer: (analyzer)#Typer

    Definition Classes
      CheckableTreeAndTypeAnalysis

### Concrete 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 MatchApproximator to any2stringadd[MatchApproximator] performed by method any2stringadd in scala.Predef.
   Definition Classes
     any2stringadd

4. #### def ->[B](y: B): (MatchApproximator, B)

   Implicit information
     This member is added by an implicit conversion from MatchApproximator to ArrowAssoc[MatchApproximator] performed by method ArrowAssoc in scala.Predef.
   Definition Classes
     ArrowAssoc
   Annotations
     @inline()

5. #### def /\(props: Iterable[Prop]): Prop

   Definition Classes
     PropositionalLogic

6. #### final def ==(arg0: Any): Boolean

   Definition Classes
     AnyRef → Any

7. #### object AnalysisBudget

   Definition Classes
     PropositionalLogic

8. #### object Const

   Definition Classes
     TreesAndTypesDomain

9. #### object EmptySubstitution extends Substitution

   Definition Classes
     TypedSubstitution

10. #### object False extends Prop with Product with Serializable

    Definition Classes
      PropositionalLogic

11. #### object IrrefutableExtractorTreeMaker

    Definition Classes
      TreeMakers

12. #### object NullConst extends Const with Product with Serializable

    Definition Classes
      TreesAndTypesDomain → PropositionalLogic

13. #### object Substitution

    Definition Classes
      TypedSubstitution

14. #### object Sym extends Serializable

    Definition Classes
      PropositionalLogic

15. #### object Test extends Serializable

16. #### object True extends Prop with Product with Serializable

    Definition Classes
      PropositionalLogic

17. #### object TypeConst extends TypeConstExtractor

    Definition Classes
      TreesAndTypesDomain → PropositionalLogic

18. #### object TypeTestTreeMaker extends Serializable

    Definition Classes
      TreeMakers

19. #### object ValueConst extends ValueConstExtractor

    Definition Classes
      TreesAndTypesDomain → PropositionalLogic

20. #### object Var extends VarExtractor

    Definition Classes
      TreesAndTypesDomain → PropositionalLogic

21. #### def \/(props: Iterable[Prop]): Prop

    Definition Classes
      PropositionalLogic

22. #### def approximateMatchConservative(root: Global.Symbol, cases: List[List[TreeMaker]]): List[List[Test]]

23. #### final def asInstanceOf[T0]: T0

    Definition Classes
      Any

24. #### final def caseWithoutBodyToProp(tests: List[Test]): Prop

    Attributes
      protected

25. #### def checkableType(tp: Global.Type): Global.Type

    Definition Classes
      CheckableTreeAndTypeAnalysis

26. #### def clone(): AnyRef

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

27. #### def combineCases(scrut: Global.Tree, scrutSym: Global.Symbol, casesRaw: List[List[TreeMaker]], pt: Global.Type, owner: Global.Symbol, matchFailGenOverride: Option[(Global.Tree) ⇒ Global.Tree]): Global.Tree

    Definition Classes
      TreeMakers

28. #### def combineCasesNoSubstOnly(scrut: Global.Tree, scrutSym: Global.Symbol, casesNoSubstOnly: List[List[TreeMaker]], pt: Global.Type, owner: Global.Symbol, matchFailGenOverride: Option[(Global.Tree) ⇒ Global.Tree]): Global.Tree

    Definition Classes
      TreeMakers

29. #### def combineExtractors(treeMakers: List[TreeMaker])(casegen: Casegen): Global.Tree

    Definition Classes
      TreeMakers

30. #### val debugInfoEmitVars: Boolean

    Attributes
      protected
    Definition Classes
      TreeMakers

31. #### def emitSwitch(scrut: Global.Tree, scrutSym: Global.Symbol, cases: List[List[TreeMaker]], pt: Global.Type, matchFailGenOverride: Option[(Global.Tree) ⇒ Global.Tree], unchecked: Boolean): Option[Global.Tree]

    Definition Classes
      TreeMakers

32. #### def emitTypeSwitch(bindersAndCases: List[(Global.Symbol, List[TreeMaker])], pt: Global.Type): Option[List[Global.CaseDef]]

    Definition Classes
      TreeMakers

33. #### def ensuring(cond: (MatchApproximator) ⇒ Boolean, msg: ⇒ Any): MatchApproximator

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

34. #### def ensuring(cond: (MatchApproximator) ⇒ Boolean): MatchApproximator

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

35. #### def ensuring(cond: Boolean, msg: ⇒ Any): MatchApproximator

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

36. #### def ensuring(cond: Boolean): MatchApproximator

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

37. #### def enumerateSubtypes(tp: Global.Type): Option[List[Global.Type]]

    Definition Classes
      CheckableTreeAndTypeAnalysis

38. #### final def eq(arg0: AnyRef): Boolean

    Definition Classes
      AnyRef

39. #### def equals(arg0: Any): Boolean

    Definition Classes
      AnyRef → Any

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

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

41. #### def fixerUpper(origOwner: Global.Symbol, pos: Global.Position): Global.Traverser

    Attributes
      protected
    Definition Classes
      TreeMakers

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

    Implicit information
      This member is added by an implicit conversion from MatchApproximator to StringFormat[MatchApproximator] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()

43. #### def freshName(prefix: String): Global.TermName

    Definition Classes
      CodegenCore

44. #### def freshSym(pos: Global.Position, tp: Global.Type = NoType, prefix: String = "x"): Global.TermSymbol

    Definition Classes
      CodegenCore

45. #### def gatherVariables(p: Prop): Set[Var]

    Definition Classes
      PropositionalLogic

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

    Definition Classes
      AnyRef → Any

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

    Definition Classes
      AnyRef → Any

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

    Definition Classes
      Any

49. #### val matchOwner: Global.Symbol

    Definition Classes
      MatchMonadInterface

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

    Definition Classes
      AnyRef

51. #### def newSynthCaseLabel(name: String): Global.MethodSymbol

    Definition Classes
      CodegenCore

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

    Definition Classes
      AnyRef

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

    Definition Classes
      AnyRef

54. #### def prepareNewAnalysis(): Unit

    Definition Classes
      TreesAndTypesDomain → PropositionalLogic

55. #### def propToSolvable(p: Prop): Formula

    Definition Classes
      PropositionalLogic

56. #### def propagateSubstitution(treeMakers: List[TreeMaker], initial: Substitution): List[TreeMaker]

    Definition Classes
      TreeMakers

57. #### def pureType(tp: Global.Type): Global.Type

    Definition Classes
      MatchMonadInterface

58. #### def removeSubstOnly(makers: List[TreeMaker]): collection.immutable.List[TreeMaker]

    Definition Classes
      TreeMakers

59. #### def removeVarEq(props: List[Prop], modelNull: Boolean = false): (Formula, List[Formula])

    Definition Classes
      PropositionalLogic

60. #### def reportMissingCases(pos: Global.Position, counterExamples: List[String]): Unit

    Definition Classes
      MatchMonadInterface

61. #### def reportUnreachable(pos: Global.Position): Unit

    Definition Classes
      MatchMonadInterface

62. #### def showTreeMakers(cases: List[List[TreeMaker]]): Unit

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

    Definition Classes
      AnyRef

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

    Definition Classes
      AnyRef → Any

65. #### def uncheckableType(tp: Global.Type): Boolean

    Definition Classes
      CheckableTreeAndTypeAnalysis

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

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

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

69. #### def →[B](y: B): (MatchApproximator, B)

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

### Inherited from MatchApproximation.TreesAndTypesDomain

### Inherited from MatchApproximation.CheckableTreeAndTypeAnalysis

### Inherited from MatchApproximation.PropositionalLogic

### Inherited from MatchApproximation.TreeMakers

### Inherited from MatchApproximation.CodegenCore

### Inherited from MatchApproximation.TypedSubstitution

### Inherited from MatchApproximation.MatchMonadInterface

### Inherited from AnyRef

### Inherited from Any

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

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

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

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

### Ungrouped