Packages

trait IsContravariant[F[_]] extends AnyRef

Type constructors that are contravariant with respect to subtyping.

A type constructor F[_] admits an instance IsContravariant[F] iff F[B] is a subtype of F[A] whenever A is a subtype of B.

The Scala language represents this natively using the [-A] notation on type constructors. The factory scalaContravariant provides an instance of this typeclass for any such type. However, type constructors which behave contravariantly despite not being thus notated can also implement this typeclass. The factory force constructs an instance of IsContravariant for any type, based on the programmer's assertion that it is indeed contravariant.

Note the relationship between this typeclass and Contravariant: whereas Contravariant instances are contravariant functors in the "category" of Scala types and functions, instances of this typeclass are contravariant functors in the "category" of Scala types and subtyping relations.

Self Type
IsContravariant[F]
Source
IsContravariant.scala
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Abstract Value Members

  1. abstract def liftLiskovCt[A, B](implicit ev: <~<[A, B]): <~<[F[B], F[A]]

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
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  4. final def asInstanceOf[T0]: T0
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    Any
  5. def clone(): AnyRef
    Attributes
    protected[lang]
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    @throws( ... ) @native()
  6. final def eq(arg0: AnyRef): Boolean
    Definition Classes
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  7. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  8. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
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    Annotations
    @throws( classOf[java.lang.Throwable] )
  9. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  10. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  11. val isContravariantSyntax: IsContravariantSyntax[F]
  12. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  13. def narrow[A, B](fa: F[B])(implicit ev: <~<[A, B]): F[A]
  14. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  15. final def notify(): Unit
    Definition Classes
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    Annotations
    @native()
  16. final def notifyAll(): Unit
    Definition Classes
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    @native()
  17. def substCo[G[+_], A, B](g: G[F[B]])(implicit ev: <~<[A, B]): G[F[A]]
  18. def substCt[G[-_], A, B](g: G[F[A]])(implicit ev: <~<[A, B]): G[F[B]]
  19. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
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  20. def toString(): String
    Definition Classes
    AnyRef → Any
  21. final def wait(): Unit
    Definition Classes
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    @throws( ... )
  22. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
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    @throws( ... )
  23. final def wait(arg0: Long): Unit
    Definition Classes
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    @throws( ... ) @native()

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