diff --git a/idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/stubBuilder/KotlinClsStubBuilder.kt b/idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/stubBuilder/KotlinClsStubBuilder.kt
index fa8b85926f8..cc4397403fc 100644
--- a/idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/stubBuilder/KotlinClsStubBuilder.kt
+++ b/idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/stubBuilder/KotlinClsStubBuilder.kt
@@ -35,7 +35,7 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.JetFile
 import org.jetbrains.kotlin.serialization.jvm.JvmProtoBufUtil
 
-public class KotlinClsStubBuilder : ClsStubBuilder() {
+public open class KotlinClsStubBuilder : ClsStubBuilder() {
     override fun getStubVersion() = ClassFileStubBuilder.STUB_VERSION + 1
 
     override fun buildFileStub(content: FileContent): PsiFileStub<*>? {