Added reproducer for jqno/equalsverifier#1081.

Author: ianbrandt

settings.gradle.kts

@@ -43,6 +43,7 @@ include("subprojects:constant-dependencies:constant-consumer")
 include("subprojects:constant-dependencies:constant-producer")
 include("subprojects:di-with-koin")
 include("subprojects:effective-kotlin")
+include("subprojects:equalsverifier-with-kotlin")
 include("subprojects:kotlin-dl")
 include("subprojects:kotlin-for-java-devs")
 include("subprojects:kotlin-for-java-devs-client")

subprojects/equalsverifier-with-kotlin/build.gradle.kts

@@ -0,0 +1,15 @@
+plugins {
+	id("org.sdkotlin.buildlogic.kotlin-project")
+	id("org.sdkotlin.buildlogic.test.unit-test-suite")
+}
+
+dependencies {
+
+	testImplementation(platform("org.sdkotlin.platforms:test-platform"))
+
+	testImplementation(libs.equalsverifier)
+
+	testRuntimeOnly(libs.mockito) {
+		because("Used by EqualsVerifier for prefab value generation.")
+	}
+}

subprojects/equalsverifier-with-kotlin/src/main/kotlin/org/sdkotlin/equalsverifier/recusive/DataClassWithSealedTypeProperty.kt

@@ -0,0 +1,41 @@
+package org.sdkotlin.equalsverifier.recusive
+
+data class DataClassWithSealedTypeProperty(
+	val foo: Foo,
+)
+
+sealed interface Foo {
+
+	val value: Int
+
+	companion object {
+		fun get(value: Int): Foo =
+			FooEnum.INSTANCES[value] ?: UnknownFooImpl(value)
+	}
+}
+
+enum class FooEnum(
+	private val delegate: Foo,
+) : Foo by delegate {
+
+	FOO_1(1),
+	FOO_2(2),
+	;
+
+	constructor(
+		value: Int,
+	) : this(FooImpl(value))
+
+	companion object {
+		val INSTANCES: Map<Int, FooEnum> =
+			entries.associateBy { enum -> enum.value }
+	}
+}
+
+internal data class FooImpl(
+	override val value: Int,
+) : Foo
+
+internal data class UnknownFooImpl(
+	override val value: Int,
+) : Foo

subprojects/equalsverifier-with-kotlin/src/test/kotlin/org/sdkotlin/equalsverifier/recusive/DataClassWithSealedTypePropertyTest.kt

@@ -0,0 +1,19 @@
+package org.sdkotlin.equalsverifier.recusive
+
+import nl.jqno.equalsverifier.EqualsVerifier
+import org.junit.jupiter.api.Test
+
+internal class DataClassWithSealedTypePropertyTest {
+
+	@Test
+	fun `test equals, hashCode, and toString`() {
+		EqualsVerifier.forClass(DataClassWithSealedTypeProperty::class.java)
+			// Required per https://github.com/jqno/equalsverifier/issues/1081.
+			.withPrefabValues(
+				Foo::class.java,
+				FooImpl(1),
+				FooImpl(2),
+			)
+			.verify()
+	}
+}