From 1b846c9d8191a50c30d63f88a4ae597419ae5735 Mon Sep 17 00:00:00 2001
From: Markus Palonen <markus.palonen@gmail.com>
Date: Tue, 17 Dec 2019 16:25:35 +0200
Subject: [PATCH] Use JSON_HAS_CPP_17 only after it has been defined

---
 .../nlohmann/detail/conversions/from_json.hpp |  8 -------
 .../nlohmann/detail/conversions/to_json.hpp   |  8 -------
 include/nlohmann/detail/macro_scope.hpp       |  8 +++++++
 single_include/nlohmann/json.hpp              | 24 +++++++------------
 4 files changed, 16 insertions(+), 32 deletions(-)

diff --git a/include/nlohmann/detail/conversions/from_json.hpp b/include/nlohmann/detail/conversions/from_json.hpp
index ca16c71122..28b10486ae 100644
--- a/include/nlohmann/detail/conversions/from_json.hpp
+++ b/include/nlohmann/detail/conversions/from_json.hpp
@@ -13,14 +13,6 @@
 #include <utility> // pair, declval
 #include <valarray> // valarray
 
-#ifdef JSON_HAS_CPP_17
-    #if __has_include(<optional>)
-        #include <optional>
-    #elif __has_include(<experimental/optional>)
-        #include <experimental/optional>
-    #endif
-#endif
-
 #include <nlohmann/detail/exceptions.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/cpp_future.hpp>
diff --git a/include/nlohmann/detail/conversions/to_json.hpp b/include/nlohmann/detail/conversions/to_json.hpp
index e9a0f6471c..4666833635 100644
--- a/include/nlohmann/detail/conversions/to_json.hpp
+++ b/include/nlohmann/detail/conversions/to_json.hpp
@@ -10,14 +10,6 @@
 #include <valarray> // valarray
 #include <vector> // vector
 
-#ifdef JSON_HAS_CPP_17
-    #if __has_include(<optional>)
-        #include <optional>
-    #elif __has_include(<experimental/optional>)
-        #include <experimental/optional>
-    #endif
-#endif
-
 #include <nlohmann/detail/iterators/iteration_proxy.hpp>
 #include <nlohmann/detail/meta/cpp_future.hpp>
 #include <nlohmann/detail/meta/type_traits.hpp>
diff --git a/include/nlohmann/detail/macro_scope.hpp b/include/nlohmann/detail/macro_scope.hpp
index 27dddc6be7..16200502bf 100644
--- a/include/nlohmann/detail/macro_scope.hpp
+++ b/include/nlohmann/detail/macro_scope.hpp
@@ -27,6 +27,14 @@
     #define JSON_HAS_CPP_14
 #endif
 
+#ifdef JSON_HAS_CPP_17
+    #if __has_include(<optional>)
+        #include <optional>
+    #elif __has_include(<experimental/optional>)
+        #include <experimental/optional>
+    #endif
+#endif
+
 // disable float-equal warnings on GCC/clang
 #if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
     #pragma GCC diagnostic push
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index ba2575b621..4cd8ed9fcb 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -69,14 +69,6 @@ SOFTWARE.
 #include <utility> // pair, declval
 #include <valarray> // valarray
 
-#ifdef JSON_HAS_CPP_17
-    #if __has_include(<optional>)
-        #include <optional>
-    #elif __has_include(<experimental/optional>)
-        #include <experimental/optional>
-    #endif
-#endif
-
 // #include <nlohmann/detail/exceptions.hpp>
 
 
@@ -1739,6 +1731,14 @@ JSON_HEDLEY_DIAGNOSTIC_POP
     #define JSON_HAS_CPP_14
 #endif
 
+#ifdef JSON_HAS_CPP_17
+    #if __has_include(<optional>)
+        #include <optional>
+    #elif __has_include(<experimental/optional>)
+        #include <experimental/optional>
+    #endif
+#endif
+
 // disable float-equal warnings on GCC/clang
 #if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
     #pragma GCC diagnostic push
@@ -3295,14 +3295,6 @@ constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::va
 #include <valarray> // valarray
 #include <vector> // vector
 
-#ifdef JSON_HAS_CPP_17
-    #if __has_include(<optional>)
-        #include <optional>
-    #elif __has_include(<experimental/optional>)
-        #include <experimental/optional>
-    #endif
-#endif
-
 // #include <nlohmann/detail/iterators/iteration_proxy.hpp>