trait TypeCheckedTripleEquals extends LowPriorityTypeCheckedConstraint

Provides === and !== operators that return Boolean, delegate the equality determination to an Equality type class, and require the types of the two values compared to be in a subtype/supertype relationship.

Recommended Usage: Trait TypeCheckedTripleEquals is useful (in both production and test code) when you need a stricter type check than is provided by the SuperSafe Community Edition compiler plugin for TripleEquals. For example, if you are developing a library that uses advanced features of Scala's type system, you may want to enforce in your tests that the types appearing in equality comparisons match exactly.

By default under TripleEquals, any use of === will compile, just like the == operator:

scala> import org.scalactic._
import org.scalactic._

scala> import TripleEquals._
import TripleEquals._

scala> 1L === 1 // A Long can equal an Int
res0: Boolean = true

scala> List(1, 2, 3) === Vector(1, 2, 3) // A List can equal a Vector
res1: Boolean = true

scala> "hi" === 1 // Likely a bug, because a String can never equal an Int
res2: Boolean = false

With SuperSafe Community Edition installed, the first two expressions above will be allowed to compile, but the third (which represents a likely bug) will not:

scala> import org.scalactic._
import org.scalactic._

scala> import TripleEquals._
import TripleEquals._

scala> 1L === 1
res0: Boolean = true

scala> List(1, 2, 3) === Vector(1, 2, 3)
res1: Boolean = true

scala> "hi" === 1 // SuperSafe catches the bug at compile time
<console>:17: error: [Artima SuperSafe] Values of type String and Int may not be compared with
the === operator. If you really want to compare them for equality, configure Artima SuperSafe to allow
those types to be compared for equality.  For more information on this kind of error, see:
http://www.artima.com/supersafe_user_guide.html#safer-equality
       "hi" === 1
            ^

By contrast, TypeCheckedTripleEquals will prevent any of the above three expressions from compiling:

scala> import org.scalactic._
import org.scalactic._

scala> import TypeCheckedTripleEquals._
import TypeCheckedTripleEquals._

scala> 1L === 1
<console>:17: error: types Long and Int do not adhere to the type constraint selected for
    the === and !== operators; the missing implicit parameter is of type org.scalactic.CanEqual[Long,Int]
       1L === 1
          ^

scala> List(1, 2, 3) === Vector(1, 2, 3)
<console>:17: error: types List[Int] and scala.collection.immutable.Vector[Int] do not adhere
    to the type constraint selected for the === and !== operators; the missing implicit parameter is
    of type org.scalactic.CanEqual[List[Int],scala.collection.immutable.Vector[Int]]
       List(1, 2, 3) === Vector(1, 2, 3)
                     ^

scala> "hi" === 1
<console>:17: error: types String and Int do not adhere to the type constraint selected for
    the === and !== operators; the missing implicit parameter is of type org.scalactic.CanEqual[String,Int]
       "hi" === 1
            ^

Trait TypeCheckedTripleEquals rejects comparisons of types Int and Long, List[Int] and Vector[Int], and String and Int, because none have a direct subtype/supertype relationship. To compare two types that are unrelated by inheritance under TypeCheckedTripleEquals, you could convert one of them to the other type (because a type is both a subtype and supertype of itself). Here's an example:

scala> 1L === 1.toLong // Now both sides are Long
res0: Boolean = true

scala> List(1, 2, 3) === Vector(1, 2, 3).toList // Now both sides are List[Int]
res1: Boolean = true

Nevertheless, a better (and the recommended) way to deal with this situation is to use a widening type ascription. A type ascription is simply a colon and a type placed next to a variable, usually surrounded by parentheses. For example, because AnyVal is a common supertype of Int and Long, you could solve the type error by widening the type of one side or the other to AnyVal. Because AnyVal is a supertype of both Int and Long, the type constraint will be satisfied:

scala> 1 === (1L: AnyVal)
res2: Boolean = true

scala> (1: AnyVal) === 1L
res3: Boolean = true

Similarly, since Seq[Int] is a common supertype of both Vector[Int] and List[Int], the type constraint can be satisfied by widening either to their common supertype, Seq[Int]:

scala> List(1, 2, 3) === (Vector(1, 2, 3): Seq[Int])
res4: Boolean = true

scala> (List(1, 2, 3): Seq[Int]) === Vector(1, 2, 3)
res5: Boolean = true

The primary intended use case for TypeCheckedTripleEquals is to enable tests to be very strict about which types can compared for equality, but it can also be used with production code where this level of strictness is desired.

Forcing implicit conversions before equality checks

You can also use a type ascription to force an implicit conversion before a value participates in an equality comparison. For example, although JavaConversions provides an implicit conversion between java.util.Set and scala.collection.mutable.Set, under TypeCheckedTripleEquals an equality comparison between those two types will not be allowed:

scala> import collection.JavaConversions._
import collection.JavaConversions._

scala> import collection.mutable
import collection.mutable

scala> import TypeCheckedTripleEquals._
import TypeCheckedTripleEquals._

scala> mutable.Set.empty[String] === new java.util.HashSet[String]
<console>:36: error: types scala.collection.mutable.Set[String] and java.util.HashSet[String] do not
    adhere to the type constraint selected for the === and !== operators; the missing implicit parameter
    is of type org.scalactic.CanEqual[scala.collection.mutable.Set[String],java.util.HashSet[String]]
       mutable.Set.empty[String] === new java.util.HashSet[String]
                                 ^

To force an implicit conversion of the Java HashSet to a Scala mutable.Set, after which the type constraint will be satisfied, you can use a type ascription:

scala> mutable.Set.empty[String] === (new java.util.HashSet[String]: mutable.Set[String])
res0: Boolean = true

Scoping equality policies

This trait will override or hide implicit methods defined by TripleEquals and can therefore be used to temporarily turn on or off type checking in a limited scope. Here's an example, in which TypeCheckedTripleEquals will cause a compiler error:

import org.scalactic._
import TypeCheckedTripleEquals._

object Example {
def cmp(a: Int, b: Long): Int = { if (a === b) 0 // This line won't compile else if (a < b) -1 else 1 }
def cmp(s: String, t: String): Int = { if (s === t) 0 else if (s < t) -1 else 1 } }

Because Int and Long are not in a subtype/supertype relationship, comparing 1 and 1L in the context of TypeCheckedTripleEquals will generate a compiler error:

Example.scala:9: error: types Int and Long do not adhere to the type constraint selected
  for the === and !== operators; the missing implicit parameter is of
  type org.scalactic.CanEqual[Int,Long]
        if (a === b) 0       // This line won't compile
              ^
one error found

You can “relax” the type checking locally by importing the members of TripleEquals in a limited scope:

package org.scalactic.examples.conversioncheckedtripleequals

import org.scalactic._ import TypeCheckedTripleEquals._
object Example {
def cmp(a: Int, b: Long): Int = { import TripleEquals._ if (a === b) 0 else if (a < b) -1 else 1 }
def cmp(s: String, t: String): Int = { if (s === t) 0 else if (s < t) -1 else 1 } }

With the above change, the Example.scala file compiles fine. The strict checking is disabled only inside the first cmp method that takes an Int and a Long. TypeCheckedTripleEquals is still enforcing its type constraint, for example, for the s === t expression in the other overloaded cmp method that takes strings.

Because the methods TripleEquals and TypeCheckedTripleEquals override all the methods defined in supertype TripleEqualsSupport, you can achieve the same kind of nested tuning of equality constraints whether you mix in traits, import from companion objects, or use some combination of both.

In short, you should be able to select a primary constraint level via either a mixin or import, then change that in nested scopes however you want, again either through a mixin or import, without getting any implicit conversion ambiguity. The innermost constraint level in scope will always be in force.

Source
TypeCheckedTripleEquals.scala
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Type Members

  1. class CheckingEqualizer[L] extends AnyRef

    Class used via an implicit conversion to enable two objects to be compared with === and !== with a Boolean result and an enforced type constraint between two object types.

    Class used via an implicit conversion to enable two objects to be compared with === and !== with a Boolean result and an enforced type constraint between two object types. For example:

    assert(a === b)
    assert(c !== d)
    

    You can also check numeric values against another with a tolerance. Here are some examples:

    assert(a === (2.0 +- 0.1))
    assert(c !== (2.0 +- 0.1))
    

    Definition Classes
    TripleEqualsSupport
  2. class Equalizer[L] extends AnyRef

    Class used via an implicit conversion to enable any two objects to be compared with === and !== with a Boolean result and no enforced type constraint between two object types.

    Class used via an implicit conversion to enable any two objects to be compared with === and !== with a Boolean result and no enforced type constraint between two object types. For example:

    assert(a === b)
    assert(c !== d)
    

    You can also check numeric values against another with a tolerance. Here are some examples:

    assert(a === (2.0 +- 0.1))
    assert(c !== (2.0 +- 0.1))
    

    Definition Classes
    TripleEqualsSupport

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. def !==[T](right: Spread[T]): TripleEqualsInvocationOnSpread[T]

    Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate the “<left> should !== (<pivot> +- <tolerance>)” syntax of Matchers.

    Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate the “<left> should !== (<pivot> +- <tolerance>)” syntax of Matchers.

    right

    the Spread[T] against which to compare the left-hand value

    returns

    a TripleEqualsInvocationOnSpread wrapping the passed Spread[T] value, with expectingEqual set to false.

    Definition Classes
    TripleEqualsSupport
  3. def !==(right: Null): TripleEqualsInvocation[Null]

    Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate the “<left> should !== null” syntax of Matchers.

    Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate the “<left> should !== null” syntax of Matchers.

    right

    a null reference

    returns

    a TripleEqualsInvocation wrapping the passed null value, with expectingEqual set to false.

    Definition Classes
    TripleEqualsSupport
  4. def !==[T](right: T): TripleEqualsInvocation[T]

    Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate the “<left> should !== <right>” syntax of Matchers.

    Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate the “<left> should !== <right>” syntax of Matchers.

    right

    the right-hand side value for an equality assertion

    returns

    a TripleEqualsInvocation wrapping the passed right value, with expectingEqual set to false.

    Definition Classes
    TripleEqualsSupport
  5. final def ##: Int
    Definition Classes
    AnyRef → Any
  6. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  7. def ===[T](right: Spread[T]): TripleEqualsInvocationOnSpread[T]

    Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate the “<left> should === (<pivot> +- <tolerance>)” syntax of Matchers.

    Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate the “<left> should === (<pivot> +- <tolerance>)” syntax of Matchers.

    right

    the Spread[T] against which to compare the left-hand value

    returns

    a TripleEqualsInvocationOnSpread wrapping the passed Spread[T] value, with expectingEqual set to true.

    Definition Classes
    TripleEqualsSupport
  8. def ===(right: Null): TripleEqualsInvocation[Null]

    Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate the “<left> should === null” syntax of Matchers.

    Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate the “<left> should === null” syntax of Matchers.

    right

    a null reference

    returns

    a TripleEqualsInvocation wrapping the passed null value, with expectingEqual set to true.

    Definition Classes
    TripleEqualsSupport
  9. def ===[T](right: T): TripleEqualsInvocation[T]

    Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate the “<left> should === <right>” syntax of Matchers.

    Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate the “<left> should === <right>” syntax of Matchers.

    right

    the right-hand side value for an equality assertion

    returns

    a TripleEqualsInvocation wrapping the passed right value, with expectingEqual set to true.

    Definition Classes
    TripleEqualsSupport
  10. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  11. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  12. implicit def convertEquivalenceToAToBConstraint[A, B](equivalenceOfB: Equivalence[B])(implicit ev: <:<[A, B]): CanEqual[A, B]

    Provides a A CanEqual B for any two types A and B, enforcing the type constraint that A must be a subtype of B, given an explicit Equivalence[B].

    Provides a A CanEqual B for any two types A and B, enforcing the type constraint that A must be a subtype of B, given an explicit Equivalence[B].

    This method is used to enable the Explicitly DSL for TypeCheckedTripleEquals by requiring an explicit Equivalance[B], but taking an implicit function that provides evidence that A is a subtype of B.

    The returned Constraint's areEqual method uses the implicitly passed Equivalence[B]'s areEquivalent method to determine equality.

    This method is overridden and made implicit by subtraits LowPriorityTypeCheckedConstraint (extended by TypeCheckedTripleEquals), and overriden as non-implicit by the other subtraits in this package.

    equivalenceOfB

    an Equivalence[B] type class to which the Constraint.areEqual method will delegate to determine equality.

    ev

    evidence that A is a subype of B

    returns

    an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of the passed Equivalence[B].

    Definition Classes
    LowPriorityTypeCheckedConstraintTripleEqualsSupport
  13. implicit def convertEquivalenceToBToAConstraint[A, B](equivalenceOfA: Equivalence[A])(implicit ev: <:<[B, A]): CanEqual[A, B]

    Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B must be a subtype of A, given an explicit Equivalence[A].

    Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B must be a subtype of A, given an explicit Equivalence[A].

    This method is used to enable the Explicitly DSL for TypeCheckedTripleEquals by requiring an explicit Equivalance[B], but taking an implicit function that provides evidence that A is a subtype of B. For example, under TypeCheckedTripleEquals, this method (as an implicit method), would be used to compile this statement:

    def closeEnoughTo1(num: Double): Boolean =
      (num === 1.0)(decided by forgivingEquality)
    

    The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

    This method is overridden and made implicit by subtraits TypeCheckedTripleEquals) and overriden as non-implicit by the other subtraits in this package.

    ev

    evidence that B is a subype of A

    returns

    an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of the passed Equivalence[A].

    Definition Classes
    TypeCheckedTripleEqualsTripleEqualsSupport
  14. implicit def convertToCheckingEqualizer[T](left: T): CheckingEqualizer[T]

    Converts to an CheckingEqualizer that provides === and !== operators that result in Boolean and enforce a type constraint.

    Converts to an CheckingEqualizer that provides === and !== operators that result in Boolean and enforce a type constraint.

    This method is overridden and made implicit by subtrait TypeCheckedTripleEquals, and overriden as non-implicit by the other subtraits in this package.

    left

    the object whose type to convert to CheckingEqualizer.

    Definition Classes
    TypeCheckedTripleEqualsTripleEqualsSupport
    Exceptions thrown

    NullPointerException if left is null.

  15. def convertToEqualizer[T](left: T): Equalizer[T]

    Converts to an Equalizer that provides === and !== operators that result in Boolean and enforce no type constraint.

    Converts to an Equalizer that provides === and !== operators that result in Boolean and enforce no type constraint.

    This method is overridden and made implicit by subtrait TripleEquals and overriden as non-implicit by the other subtraits in this package.

    left

    the object whose type to convert to Equalizer.

    Definition Classes
    TypeCheckedTripleEqualsTripleEqualsSupport
    Exceptions thrown

    NullPointerException if left is null.

  16. def defaultEquality[A]: Equality[A]

    Returns an Equality[A] for any type A that determines equality by first calling .deep on any Array (on either the left or right side), then comparing the resulting objects with ==.

    Returns an Equality[A] for any type A that determines equality by first calling .deep on any Array (on either the left or right side), then comparing the resulting objects with ==.

    returns

    a default Equality for type A

    Definition Classes
    TripleEqualsSupport
  17. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  18. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  19. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  20. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  21. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  22. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  23. implicit def lowPriorityTypeCheckedConstraint[A, B](implicit equivalenceOfB: Equivalence[B], ev: <:<[A, B]): CanEqual[A, B]

    Provides an A CanEqual B for any two types A and B, enforcing the type constraint that A must be a subtype of B, given an implicit Equivalence[B].

    Provides an A CanEqual B for any two types A and B, enforcing the type constraint that A must be a subtype of B, given an implicit Equivalence[B].

    The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

    This method is overridden and made implicit by subtraits LowPriorityTypeCheckedConstraint (extended by TypeCheckedTripleEquals), and overriden as non-implicit by the other subtraits in this package.

    equivalenceOfB

    an Equivalence[B] type class to which the Constraint.areEqual method will delegate to determine equality.

    ev

    evidence that A is a subype of B

    returns

    an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of the passed Equivalence[B].

    Definition Classes
    LowPriorityTypeCheckedConstraintTripleEqualsSupport
  24. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  25. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  26. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  27. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  28. def toString(): String
    Definition Classes
    AnyRef → Any
  29. implicit def typeCheckedConstraint[A, B](implicit equivalenceOfA: Equivalence[A], ev: <:<[B, A]): CanEqual[A, B]

    Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B must be a subtype of A, given an implicit Equivalence[A].

    Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B must be a subtype of A, given an implicit Equivalence[A].

    The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

    This method is overridden and made implicit by subtraits TypeCheckedTripleEquals) and overriden as non-implicit by the other subtraits in this package.

    ev

    evidence that B is a subype of A

    returns

    an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of the passed Equivalence[A].

    Definition Classes
    TypeCheckedTripleEqualsTripleEqualsSupport
  30. def unconstrainedEquality[A, B](implicit equalityOfA: Equality[A]): CanEqual[A, B]

    Provides an A CanEqual B instance for any two types A and B, with no type constraint enforced, given an implicit Equality[A].

    Provides an A CanEqual B instance for any two types A and B, with no type constraint enforced, given an implicit Equality[A].

    The returned Constraint's areEqual method uses the implicitly passed Equality[A]'s areEqual method to determine equality.

    This method is overridden and made implicit by subtraits TripleEquals and overriden as non-implicit by the other subtraits in this package.

    equalityOfA

    an Equality[A] type class to which the Constraint.areEqual method will delegate to determine equality.

    returns

    an A CanEqual B instance whose areEqual method delegates to the areEqual method of the passed Equality[A].

    Definition Classes
    TypeCheckedTripleEqualsTripleEqualsSupport
  31. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  32. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  33. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()

Deprecated Value Members

  1. def conversionCheckedConstraint[A, B](implicit equivalenceOfA: Equivalence[A], cnv: (B) => A): CanEqual[A, B]

    The conversionCheckedConstraint method has been deprecated and will be removed in a future version of Scalactic. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

    The conversionCheckedConstraint method has been deprecated and will be removed in a future version of Scalactic. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

    Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B is implicitly convertible to A, given an implicit Equivalence[A].

    The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

    This method is overridden and made implicit by subtraits ConversionCheckedTripleEquals) and overriden as non-implicit by the other subtraits in this package.

    equivalenceOfA

    an Equivalence[A] type class to which the Constraint.areEqual method will delegate to determine equality.

    cnv

    an implicit conversion from B to A

    returns

    an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of the passed Equivalence[A].

    Definition Classes
    TypeCheckedTripleEqualsTripleEqualsSupport
    Annotations
    @deprecated
    Deprecated

    (Since version 3.1.0) The conversionCheckedConstraint method has been deprecated and will be removed in a future version of ScalaTest. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

  2. def convertEquivalenceToAToBConversionConstraint[A, B](equivalenceOfB: Equivalence[B])(implicit ev: (A) => B): CanEqual[A, B]

    The convertEquivalenceToAToBConversionConstraint method has been deprecated and will be removed in a future version of Scalactic. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

    The convertEquivalenceToAToBConversionConstraint method has been deprecated and will be removed in a future version of Scalactic. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

    Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that A is implicitly convertible to B, given an explicit Equivalence[B].

    This method is used to enable the Explicitly DSL for ConversionCheckedTripleEquals by requiring an explicit Equivalance[B], but taking an implicit function that converts from A to B.

    The returned Constraint's areEqual method uses the implicitly passed Equivalence[B]'s areEquivalent method to determine equality.

    This method is overridden and made implicit by subtraits LowPriorityConversionCheckedConstraint (extended by ConversionCheckedTripleEquals), and overriden as non-implicit by the other subtraits in this package.

    returns

    an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of the passed Equivalence[B].

    Definition Classes
    TypeCheckedTripleEqualsTripleEqualsSupport
    Annotations
    @deprecated
    Deprecated

    (Since version 3.1.0) The convertEquivalenceToAToBConversionConstraint method has been deprecated and will be removed in a future version of ScalaTest. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

  3. def convertEquivalenceToBToAConversionConstraint[A, B](equivalenceOfA: Equivalence[A])(implicit ev: (B) => A): CanEqual[A, B]

    The convertEquivalenceToBToAConversionConstraint method has been deprecated and will be removed in a future version of Scalactic. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

    The convertEquivalenceToBToAConversionConstraint method has been deprecated and will be removed in a future version of Scalactic. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

    Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B is implicitly convertible to A, given an explicit Equivalence[A].

    This method is used to enable the Explicitly DSL for ConversionCheckedTripleEquals by requiring an explicit Equivalance[A], but taking an implicit function that converts from B to A. For example, under ConversionCheckedTripleEquals, this method (as an implicit method), would be used to compile this statement:

    def closeEnoughTo1(num: Double): Boolean =
      (num === 1.0)(decided by forgivingEquality)
    

    The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s areEquivalent method to determine equality.

    This method is overridden and made implicit by subtraits ConversionCheckedTripleEquals) and overriden as non-implicit by the other subtraits in this package.

    equivalenceOfA

    an Equivalence[A] type class to which the Constraint.areEqual method will delegate to determine equality.

    returns

    an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of the passed Equivalence[A].

    Definition Classes
    TypeCheckedTripleEqualsTripleEqualsSupport
    Annotations
    @deprecated
    Deprecated

    (Since version 3.1.0) The convertEquivalenceToBToAConversionConstraint method has been deprecated and will be removed in a future version of ScalaTest. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

  4. def lowPriorityConversionCheckedConstraint[A, B](implicit equivalenceOfB: Equivalence[B], cnv: (A) => B): CanEqual[A, B]

    The lowPriorityConversionCheckedConstraint method has been deprecated and will be removed in a future version of Scalactic. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

    The lowPriorityConversionCheckedConstraint method has been deprecated and will be removed in a future version of Scalactic. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

    Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that A is implicitly convertible to B, given an implicit Equivalence[B].

    The returned Constraint's areEqual method uses the implicitly passed Equivalence[B]'s areEquivalent method to determine equality.

    This method is overridden and made implicit by subtraits LowPriorityConversionCheckedConstraint (extended by ConversionCheckedTripleEquals), and overriden as non-implicit by the other subtraits in this package.

    cnv

    an implicit conversion from A to B

    returns

    an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of the passed Equivalence[B].

    Definition Classes
    TypeCheckedTripleEqualsTripleEqualsSupport
    Annotations
    @deprecated
    Deprecated

    (Since version 3.1.0) The lowPriorityConversionCheckedConstraint method has been deprecated and will be removed in a future version of ScalaTest. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.

Inherited from TripleEqualsSupport

Inherited from AnyRef

Inherited from Any

Ungrouped