KT-4107 Data objects

compiler/testData/codegen/box/dataObjects/toString.kt

@@ -0,0 +1,52 @@
+// LANGUAGE: +DataObjects
+// WITH_STDLIB
+
+package com.example
+
+import kotlin.test.*
+
+data object DataObject {
+    data object Nested
+}
+
+class Foo {
+    data object Inner
+}
+
+data object Declared {
+    override fun toString() = "Overriden"
+}
+
+open class WithFinalToString {
+    final override fun toString() = "FinalToString"
+}
+
+data object InheritedFromClassWithFinalToString: WithFinalToString()
+
+open class WithOpenToString {
+    override fun toString() = "OpenToString"
+}
+
+data object InheritedFromClassWithOpenToString: WithOpenToString()
+
+abstract class WithAbstractToString {
+    abstract override fun toString(): String
+}
+
+data object InheritedFromClassWithAbstractToString : WithAbstractToString()
+
+class C {
+    companion object CC
+}
+
+fun box(): String {
+    assertEquals("DataObject", DataObject.toString())
+    assertEquals("Nested", DataObject.Nested.toString())
+    assertEquals("Inner", Foo.Inner.toString())
+    assertEquals("Overriden", Declared.toString())
+    assertEquals("FinalToString", InheritedFromClassWithFinalToString.toString())
+    assertEquals("InheritedFromClassWithOpenToString", InheritedFromClassWithOpenToString.toString())
+    assertEquals("InheritedFromClassWithAbstractToString", InheritedFromClassWithAbstractToString.toString())
+
+    return "OK"
+}