diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/checkers/ExperimentalUsageChecker.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/checkers/ExperimentalUsageChecker.kt
index 7a2a14af573..56cf38f33dc 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/checkers/ExperimentalUsageChecker.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/checkers/ExperimentalUsageChecker.kt
@@ -130,7 +130,7 @@ class ExperimentalUsageChecker(project: Project) : CallChecker {
             if (annotations.any { it.fqName == WAS_EXPERIMENTAL_FQ_NAME }) {
                 val accessibility = checkSinceKotlinVersionAccessibility(languageVersionSettings)
                 if (accessibility is SinceKotlinAccessibility.NotAccessibleButWasExperimental) {
-                    result.addAll(accessibility.markerClasses.map { it.loadExperimentalityForMarkerAnnotation() })
+                    result.addAll(accessibility.markerClasses.mapNotNull { it.loadExperimentalityForMarkerAnnotation() })
                 }
             }