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 f42ebe77117..6139b895410 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
@@ -987,6 +987,7 @@ class FirElementSerializer private constructor(
             builder.addArgument(typeArgument(typeArguments[argumentIndex++]))
         }
 
+        if (!symbol.isInner) return
         val outerClassId = symbol.classId.outerClassId
         if (outerClassId == null || outerClassId.isLocal) return
         val outerSymbol = outerClassId.toLookupTag().toSymbol(session)