From 717a307ff22c500d630ba0c6fe4263d75c2a8533 Mon Sep 17 00:00:00 2001
From: levlam <levlam@telegram.org>
Date: Thu, 12 Apr 2018 12:11:48 +0300
Subject: [PATCH] Fix clang 3.4-3.5 CE (2).

GitOrigin-RevId: 3ebf199d67ce42ea63add34aeb982debe8a9af3d
---
 tdutils/td/utils/optional.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tdutils/td/utils/optional.h b/tdutils/td/utils/optional.h
index 8b74f43b3..b1c4244e3 100644
--- a/tdutils/td/utils/optional.h
+++ b/tdutils/td/utils/optional.h
@@ -16,7 +16,7 @@ template <class T>
 class optional {
  public:
   optional() = default;
-  template <class T1>
+  template <class T1, std::enable_if_t<!std::is_same<std::decay_t<T1>, optional>::value, int> = 0>
   optional(T1 &&t) : impl_(std::forward<T1>(t)) {
   }
   explicit operator bool() const {