diff --git a/core/util.runtime/src/org/jetbrains/jet/utils/collections.kt b/core/util.runtime/src/org/jetbrains/jet/utils/collections.kt
index 301f562946a..fa20409d6f1 100644
--- a/core/util.runtime/src/org/jetbrains/jet/utils/collections.kt
+++ b/core/util.runtime/src/org/jetbrains/jet/utils/collections.kt
@@ -55,4 +55,6 @@ public fun <K, V: Any> Iterator<K>.keysToMapExceptNulls(value: (K) -> V?): Map<K
         }
     }
     return map
-}
\ No newline at end of file
+}
+
+public fun <T, C: Collection<T>> C.ifEmpty(body: () -> C): C = if (isEmpty()) body() else this
\ No newline at end of file