Merge pull request #1551 from heavywatal/fix-1535-nodiscard-clang

Remove C++17 extension warning from clang; #1535

Merge pull request #1551 from heavywatal/fix-1535-nodiscard-clang
b52c3638 · Niels Lohmann · GitHub · d21d2983 · 5ccdaf64 · b52c3638
Unverified Commit b52c3638 authored Mar 29, 2019 by Niels Lohmann Committed by GitHub Mar 29, 2019
Hide whitespace changes
Inline Side-by-side

Showing with 26 additions and 18 deletions

macro_scope.hpp include/nlohmann/detail/macro_scope.hpp +13 -9

json.hpp single_include/nlohmann/json.hpp +13 -9

No files found.
--- a/include/nlohmann/detail/macro_scope.hpp
+++ b/include/nlohmann/detail/macro_scope.hpp
@@ -18,6 +18,14 @@
    #endif
 #endif

+// C++ language standard detection
+#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
+    #define JSON_HAS_CPP_17
+    #define JSON_HAS_CPP_14
+#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
+    #define JSON_HAS_CPP_14
+#endif
+
 // disable float-equal warnings on GCC/clang
 #if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
    #pragma GCC diagnostic push
@@ -42,7 +50,11 @@
 // allow for portable nodiscard warnings
 #if defined(__has_cpp_attribute)
    #if __has_cpp_attribute(nodiscard)
-        #define JSON_NODISCARD [[nodiscard]]
+        #if defined(__clang__) && !defined(JSON_HAS_CPP_17) // issue #1535
+            #define JSON_NODISCARD
+        #else
+            #define JSON_NODISCARD [[nodiscard]]
+        #endif
    #elif __has_cpp_attribute(gnu::warn_unused_result)
        #define JSON_NODISCARD [[gnu::warn_unused_result]]
    #else
@@ -95,14 +107,6 @@
    #define JSON_UNLIKELY(x)    x
 #endif

-// C++ language standard detection
-#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
-    #define JSON_HAS_CPP_17
-    #define JSON_HAS_CPP_14
-#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
-    #define JSON_HAS_CPP_14
-#endif
-
 /*!
 @brief macro to briefly define a mapping between an enum and JSON
 @def NLOHMANN_JSON_SERIALIZE_ENUM

--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -469,6 +469,14 @@ class other_error : public exception
    #endif
 #endif

+// C++ language standard detection
+#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
+    #define JSON_HAS_CPP_17
+    #define JSON_HAS_CPP_14
+#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
+    #define JSON_HAS_CPP_14
+#endif
+
 // disable float-equal warnings on GCC/clang
 #if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__)
    #pragma GCC diagnostic push
@@ -493,7 +501,11 @@ class other_error : public exception
 // allow for portable nodiscard warnings
 #if defined(__has_cpp_attribute)
    #if __has_cpp_attribute(nodiscard)
-        #define JSON_NODISCARD [[nodiscard]]
+        #if defined(__clang__) && !defined(JSON_HAS_CPP_17) // issue #1535
+            #define JSON_NODISCARD
+        #else
+            #define JSON_NODISCARD [[nodiscard]]
+        #endif
    #elif __has_cpp_attribute(gnu::warn_unused_result)
        #define JSON_NODISCARD [[gnu::warn_unused_result]]
    #else
@@ -546,14 +558,6 @@ class other_error : public exception
    #define JSON_UNLIKELY(x)    x
 #endif

-// C++ language standard detection
-#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
-    #define JSON_HAS_CPP_17
-    #define JSON_HAS_CPP_14
-#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
-    #define JSON_HAS_CPP_14
-#endif
-
 /*!
 @brief macro to briefly define a mapping between an enum and JSON
 @def NLOHMANN_JSON_SERIALIZE_ENUM