From ebfbfe95158fd074fa057930e1e0fb858059e358 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 30 Jan 2020 01:10:26 +0100
Subject: [PATCH] Use std::nullopt

---
 src/nix/flake.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/nix/flake.cc b/src/nix/flake.cc
index 295383681..dafd1ae7e 100644
--- a/src/nix/flake.cc
+++ b/src/nix/flake.cc
@@ -645,7 +645,7 @@ struct CmdFlakeArchive : FlakeCommand, MixJSON, MixDryRun
     {
         auto flake = lockFlake();
 
-        auto jsonRoot = json ? std::optional<JSONObject>(std::cout) : std::optional<JSONObject>();
+        auto jsonRoot = json ? std::optional<JSONObject>(std::cout) : std::nullopt;
 
         StorePathSet sources;