Make deprecated API hidden, replace deprecated API with new one
diff --git a/core/kotlinx-coroutines-core/src/main/kotlin/kotlinx/coroutines/experimental/Future.kt b/core/kotlinx-coroutines-core/src/main/kotlin/kotlinx/coroutines/experimental/Future.kt
index 6909b99..3490d14 100644
--- a/core/kotlinx-coroutines-core/src/main/kotlin/kotlinx/coroutines/experimental/Future.kt
+++ b/core/kotlinx-coroutines-core/src/main/kotlin/kotlinx/coroutines/experimental/Future.kt
@@ -41,7 +41,7 @@
 @Deprecated(
     message = "Disposable handlers on regular completion are no longer supported",
     replaceWith = ReplaceWith("cancelFutureOnCancellation(future)"),
-    level = DeprecationLevel.WARNING)
+    level = DeprecationLevel.HIDDEN)
 public fun CancellableContinuation<*>.cancelFutureOnCompletion(future: Future<*>): DisposableHandle {
     cancelFutureOnCancellation(future)
     return NonDisposableHandle