Fixed bug with nested enums lowering + test

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/EnumClassLowering.kt

@@ -599,6 +599,12 @@ internal class EnumClassLowering(val context: Context) : ClassLoweringPass {
         private inner class EnumClassBodyTransformer : IrElementTransformerVoid() {
             private var enumConstructorCallTransformer: EnumConstructorCallTransformer? = null
 
+            override fun visitClass(declaration: IrClass): IrStatement {
+                if (declaration.descriptor.kind == ClassKind.ENUM_CLASS)
+                    return declaration
+                return super.visitClass(declaration)
+            }
+
             override fun visitEnumEntry(declaration: IrEnumEntry): IrStatement {
                 assert(enumConstructorCallTransformer == null) { "Nested enum entry initialization:\n${declaration.dump()}" }
 

backend.native/tests/build.gradle

@@ -671,6 +671,11 @@ task enum_varargParam(type: RunKonanTest) {
     source = "codegen/enum/varargParam.kt"
 }
 
+task enum_nested(type: RunKonanTest) {
+    goldValue = "A\nC\n"
+    source = "codegen/enum/nested.kt"
+}
+
 task mangling(type: LinkKonanTest) {
     goldValue = 
         "Int direct [1, 2, 3, 4]\n" +

backend.native/tests/codegen/enum/nested.kt

@@ -0,0 +1,13 @@
+package codegen.enum.nested
+
+import kotlin.test.*
+
+enum class Foo {
+    A;
+    enum class Bar { C }
+}
+
+@Test fun runTest() {
+    println(Foo.A)
+    println(Foo.Bar.C)
+}