diff --git a/compiler/testData/codegen/box/casts/functions/asFunKSmall.kt b/compiler/testData/codegen/box/casts/functions/asFunKSmall.kt
index ba59dbf1e1d..94d2cffd936 100644
--- a/compiler/testData/codegen/box/casts/functions/asFunKSmall.kt
+++ b/compiler/testData/codegen/box/casts/functions/asFunKSmall.kt
@@ -1,3 +1,6 @@
+// FIR inserts incorrect smart casts based on the cast in the
+// lambda. However, that cast can fail and the failure can be caught
+// by the inline function.
 // IGNORE_BACKEND: JS_IR
 // TODO: muted automatically, investigate should it be ran for JS or not
 // IGNORE_BACKEND: JS, NATIVE