diff --git a/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.fir.ir.txt b/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.fir.ir.txt
index 9017d07e7fc..383d6f1976a 100644
--- a/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.fir.ir.txt
+++ b/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.fir.ir.txt
@@ -143,5 +143,22 @@ FILE fqName:<root> fileName:/selfReferentialAnnotation.kt
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
   FUN name:box visibility:public modality:FINAL <> () returnType:kotlin.String
     BLOCK_BODY
+      VAR name:result type:kotlin.String [val]
+        CALL 'public final fun joinToString <T> (separator: kotlin.CharSequence, prefix: kotlin.CharSequence, postfix: kotlin.CharSequence, limit: kotlin.Int, truncated: kotlin.CharSequence, transform: kotlin.Function1<T of kotlin.collections.joinToString, kotlin.CharSequence>?): kotlin.String declared in kotlin.collections' type=kotlin.String origin=null
+          <T>: <root>.MyRequiresOptIn.MyLevel
+          $receiver: CALL 'public final fun values (): kotlin.Array<<root>.MyRequiresOptIn.MyLevel> declared in <root>.MyRequiresOptIn.MyLevel' type=kotlin.Array<<root>.MyRequiresOptIn.MyLevel> origin=null
       RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
-        CONST String type=kotlin.String value="OK"
+        BLOCK type=kotlin.String origin=WHEN
+          VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:kotlin.String [val]
+            GET_VAR 'val result: kotlin.String declared in <root>.box' type=kotlin.String origin=null
+          WHEN type=kotlin.String origin=WHEN
+            BRANCH
+              if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
+                arg0: GET_VAR 'val tmp_0: kotlin.String declared in <root>.box' type=kotlin.String origin=null
+                arg1: CONST String type=kotlin.String value="WARNING, ERROR"
+              then: CONST String type=kotlin.String value="OK"
+            BRANCH
+              if: CONST Boolean type=kotlin.Boolean value=true
+              then: STRING_CONCATENATION type=kotlin.String
+                CONST String type=kotlin.String value="Fail: "
+                GET_VAR 'val result: kotlin.String declared in <root>.box' type=kotlin.String origin=null
diff --git a/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.fir.txt b/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.fir.txt
index 42217e20fbf..6c8d04ce777 100644
--- a/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.fir.txt
+++ b/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.fir.txt
@@ -39,5 +39,14 @@ FILE: selfReferentialAnnotation.kt
 
     }
     public final fun box(): R|kotlin/String| {
-        ^box String(OK)
+        lval result: R|kotlin/String| = Q|MyRequiresOptIn.MyLevel|.R|/MyRequiresOptIn.MyLevel.values*s|().R|kotlin/collections/joinToString|<R|MyRequiresOptIn.MyLevel|>()
+        ^box when (R|<local>/result|) {
+            ==($subj$, String(WARNING, ERROR)) ->  {
+                String(OK)
+            }
+            else ->  {
+                <strcat>(String(Fail: ), R|<local>/result|)
+            }
+        }
+
     }
diff --git a/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.ir.txt b/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.ir.txt
index 7ef873eec23..238879d394f 100644
--- a/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.ir.txt
+++ b/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.ir.txt
@@ -143,5 +143,22 @@ FILE fqName:<root> fileName:/selfReferentialAnnotation.kt
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
   FUN name:box visibility:public modality:FINAL <> () returnType:kotlin.String
     BLOCK_BODY
+      VAR name:result type:kotlin.String [val]
+        CALL 'public final fun joinToString <T> (separator: kotlin.CharSequence, prefix: kotlin.CharSequence, postfix: kotlin.CharSequence, limit: kotlin.Int, truncated: kotlin.CharSequence, transform: kotlin.Function1<T of kotlin.collections.joinToString, kotlin.CharSequence>?): kotlin.String declared in kotlin.collections' type=kotlin.String origin=null
+          <T>: <root>.MyRequiresOptIn.MyLevel
+          $receiver: CALL 'public final fun values (): kotlin.Array<<root>.MyRequiresOptIn.MyLevel> declared in <root>.MyRequiresOptIn.MyLevel' type=kotlin.Array<<root>.MyRequiresOptIn.MyLevel> origin=null
       RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
-        CONST String type=kotlin.String value="OK"
+        BLOCK type=kotlin.String origin=WHEN
+          VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:kotlin.String [val]
+            GET_VAR 'val result: kotlin.String declared in <root>.box' type=kotlin.String origin=null
+          WHEN type=kotlin.String origin=WHEN
+            BRANCH
+              if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
+                arg0: GET_VAR 'val tmp_0: kotlin.String declared in <root>.box' type=kotlin.String origin=null
+                arg1: CONST String type=kotlin.String value="WARNING, ERROR"
+              then: CONST String type=kotlin.String value="OK"
+            BRANCH
+              if: CONST Boolean type=kotlin.Boolean value=true
+              then: STRING_CONCATENATION type=kotlin.String
+                CONST String type=kotlin.String value="Fail: "
+                GET_VAR 'val result: kotlin.String declared in <root>.box' type=kotlin.String origin=null
diff --git a/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.kt b/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.kt
index 4b8adc554f0..79c6324c908 100644
--- a/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.kt
+++ b/compiler/testData/codegen/box/annotations/selfReferentialAnnotation.kt
@@ -1,5 +1,7 @@
 // FIR_DUMP
 // DUMP_IR
+// WITH_STDLIB
+// IGNORE_BACKEND_K2: ANY
 
 annotation class Ann(@Ann(1) val e: Int)
 
@@ -14,4 +16,10 @@ public annotation class MyRequiresOptIn(
     }
 }
 
-fun box() = "OK"
\ No newline at end of file
+fun box(): String {
+    val result = MyRequiresOptIn.MyLevel.values().joinToString()
+    return when (result) {
+        "WARNING, ERROR" -> "OK"
+        else -> "Fail: $result"
+    }
+}