diff --git a/compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/FirElementSerializer.kt b/compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/FirElementSerializer.kt
index d6d8d0cc3e2..4358e9ca1b8 100644
--- a/compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/FirElementSerializer.kt
+++ b/compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/FirElementSerializer.kt
@@ -592,8 +592,7 @@ class FirElementSerializer private constructor(
                 }
             }
             is ConeDefinitelyNotNullType,
-            is ConeIntersectionType,
-            is ConeIntegerLiteralType -> {
+            is ConeIntersectionType -> {
                 val approximatedType = if (toSuper) {
                     typeApproximator.approximateToSuperType(type, TypeApproximatorConfiguration.PublicDeclaration)
                 } else {
@@ -604,6 +603,9 @@ class FirElementSerializer private constructor(
                 }
                 return typeProto(approximatedType as ConeKotlinType)
             }
+            is ConeIntegerLiteralType -> {
+                throw IllegalStateException("Integer literal types should not persist up to the serializer: ${type.render()}")
+            }
             is ConeCapturedType -> {
                 throw IllegalStateException("Captured types should not persist up to the serializer: ${type.render()}")
             }