diff --git a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt
index a75052e8add..40b7564c189 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/common/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt
@@ -549,7 +549,8 @@ abstract class KotlinCompile @Inject constructor(
 
     @Deprecated(
         "Replaced with 'libraries' input",
-        replaceWith = ReplaceWith("libraries")
+        replaceWith = ReplaceWith("libraries"),
+        level = DeprecationLevel.ERROR
     )
     @get:Internal
     var classpath: FileCollection