KT-4107 Data objects

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

@@ -0,0 +1,15 @@
+// LANGUAGE: +DataObjects
+// WITH_STDLIB
+
+package com.example
+
+import kotlin.test.*
+
+data object DataObject
+
+fun box(): String {
+    assertEquals(DataObject, DataObject)
+    assertFalse(DataObject == null)
+
+    return  "OK"
+}