JS: add tests to show that #KT-12865 fixed as well

compiler/testData/codegen/box/classes/implementComparableInSubclass.kt

@@ -0,0 +1,22 @@
+// See KT-12865
+
+package foo
+
+abstract class Base {
+    val x = 23
+}
+
+class Derived : Base(), Comparable<Derived> {
+    val y = 42
+    override fun compareTo(other: Derived): Int {
+        throw UnsupportedOperationException("not implemented")
+    }
+}
+
+fun box(): String {
+    val b = Derived()
+    if (b.x != 23) return "fail1: ${b.x}"
+    if (b.y != 42) return "fail2: ${b.y}"
+
+    return "OK"
+}

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -2599,6 +2599,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("implementComparableInSubclass.kt")
+        public void testImplementComparableInSubclass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/classes/implementComparableInSubclass.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("inheritSetAndHashSet.kt")
         public void testInheritSetAndHashSet() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/classes/inheritSetAndHashSet.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/ClassesTestGenerated.java

@@ -227,6 +227,12 @@ public class ClassesTestGenerated extends AbstractClassesTest {
         doTest(fileName);
     }
 
+    @TestMetadata("implementComparableInSubclass.kt")
+    public void testImplementComparableInSubclass() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/classes/implementComparableInSubclass.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("inheritSetAndHashSet.kt")
     public void testInheritSetAndHashSet() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/classes/inheritSetAndHashSet.kt");