version 0.4.1

README.md

@@ -48,7 +48,7 @@ This library requires **[Scala 3.3](https://scala-lang.org/blog/2023/05/30/scala
 
 Include the library dependency in your `build.sbt` and enable strict equality:
 ```scala
-libraryDependencies += "ch.produs" %% "type-safe-equality" % "0.4.0"
+libraryDependencies += "ch.produs" %% "type-safe-equality" % "0.4.1"
 
 scalacOptions += "-language:strictEquality"
 scalacOptions += "-Yimports:scala,scala.Predef,java.lang,equality.all"
@@ -151,7 +151,7 @@ SomeProduct() == SomeProduct()
 
 Assumed equality for the bottom classes of a class hierarchy via type class derivation:
 ```scala
-abstract class Animal
+class Animal
 case class Cat() extends Animal derives Eq.assumed
 case class Dog() extends Animal derives Eq.assumed
 
@@ -162,7 +162,7 @@ case class Dog() extends Animal derives Eq.assumed
 
 Assumed equality for the base class of a class hierarchy via type class derivation:
 ```scala
-abstract class Animal derives Eq.assumed
+class Animal derives Eq.assumed
 case class Cat() extends Animal
 case class Dog() extends Animal
 

build.sbt

@@ -5,7 +5,7 @@ ThisBuild / organizationHomepage := None
 ThisBuild / description := "Scala 3 type safe equality"
 ThisBuild / homepage := Some(url("https://github.com/antognini/type-safe-equality"))
 ThisBuild / licenses := Seq("Apache-2.0" -> url("https://www.apache.org/licenses/LICENSE-2.0"))
-ThisBuild / version := "0.4.0"
+ThisBuild / version := "0.4.1"
 ThisBuild / scalaVersion := "3.3.0"
 ThisBuild / versionScheme := Some("semver-spec")
 ThisBuild / publishTo := sonatypePublishToBundle.value

eq/src/main/scala/equality/Eq.scala

@@ -17,8 +17,6 @@ sealed trait Eq[-T]:
    */
   private[equality] val violations: Seq[String] = Nil
 
-  override def toString = "Eq.derived"
-
 object Eq:
   given eq_CanEqual[T: Eq]: CanEqual[T, T] = CanEqual.derived
 
@@ -31,16 +29,13 @@ object Eq:
   object assumed extends assumed[Any]:
     def derived[T]: assumed[T] = assumed
 
-    override def toString = "Eq.assumed"
-
   /**
    * Creates an Eq instance for an arbitrary type without verifying equality requirements.
    *
    * @see [[https://github.com/antognini/type-safe-equality/blob/main/README.md#assuming-equality Library documentation]]
    * @tparam T arbitrary type
    */
-  sealed trait assumed[-T] extends Eq[T]:
-    override def toString = "Eq.assumed"
+  sealed trait assumed[-T] extends Eq[T]
 
   /**
    * Creates an Eq instance for a `Product` type while verifying equality requirements.
@@ -64,6 +59,6 @@ object Eq:
   // For testing only
   private[equality] def apply[T](violationSeq: Seq[String]): Eq[T] =
     new Eq[T]:
-      override val violations: Seq[String] = violationSeq
+      override val violations = violationSeq
 
 end Eq

eq/src/main/scala/equality/EqRef.scala

@@ -1,14 +1,13 @@
 package equality
 
-import equality.Eq
-
+import equality.all.{Eq, given}
 
 /**
  * Equality-safe reference comparison.
  *
  * @see [[https://github.com/antognini/type-safe-equality/tree/main#reference-equality Library documentation]]
  */
-sealed trait EqRef[A <: AnyRef](
+sealed class EqRef[A <: AnyRef] private (
   private val a: Option[A]
 ) derives Eq.assumed:
 
@@ -50,13 +49,15 @@ sealed trait EqRef[A <: AnyRef](
     a match
       case Some(value) =>
         val identity = System.identityHashCode(value)
-        s"EqRef($identity -> $value)"
+        f"EqRef($identity%x -> $value)"
       case _ =>
-        s"EqRef"
+        "EqRef"
 
 end EqRef
 
 object EqRef:
-  def apply[A <: AnyRef]: EqRef[A] = new EqRef[A](None){}
-  def apply[A <: AnyRef](a: A): EqRef[A] = new EqRef[A](Some(a)){}
+  def apply[A <: AnyRef]: EqRef[A] = new EqRef[A](None)
+  def apply[A <: AnyRef](a: A): EqRef[A] = new EqRef[A](Some(a))
+
+  given [A <: AnyRef]: Eq[EqRef[A]] = Eq.assumed
 end EqRef

examples/src/main/scala/examples/Quickstart.scala

@@ -91,7 +91,7 @@ def verified_equality_for_an_existing_arbitrary_class_with_a_given: Unit =
 @nowarn
 def assumed_equality_for_the_bottom_classes_of_a_class_hierarchy_via_type_class_derivation: Unit =
 
-  abstract class Animal
+  class Animal
   case class Cat() extends Animal derives Eq.assumed
   case class Dog() extends Animal derives Eq.assumed
 
@@ -103,7 +103,7 @@ def assumed_equality_for_the_bottom_classes_of_a_class_hierarchy_via_type_class_
 @nowarn
 def assumed_equality_for_the_base_class_of_a_class_hierarchy_via_type_class_derivation: Unit =
 
-  abstract class Animal derives Eq.assumed
+  class Animal derives Eq.assumed
   case class Cat() extends Animal
   case class Dog() extends Animal