diff --git a/src/commonMain/kotlin/ru/landrafhomyak/utility/reference_counter/MayBeClosedReferenceCounter.kt b/src/commonMain/kotlin/ru/landrafhomyak/utility/reference_counter/MayBeClosedReferenceCounter.kt
index 01a5526..6771c9a 100644
--- a/src/commonMain/kotlin/ru/landrafhomyak/utility/reference_counter/MayBeClosedReferenceCounter.kt
+++ b/src/commonMain/kotlin/ru/landrafhomyak/utility/reference_counter/MayBeClosedReferenceCounter.kt
@@ -76,6 +76,9 @@ public sealed class MayBeClosedReferenceCounter {
 
 	@JvmName("withRef\$kt")
 	public inline fun <R> withRef(protected: () -> R): R {
+		contract {
+			callsInPlace(protected, InvocationKind.EXACTLY_ONCE)
+		}
 		this.incref()
 		return safeAutoClose1(finally = this::decref, action = protected)
 	}