diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 6f956dabf..21e97d4ca 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -2387,10 +2387,10 @@ JSON_HEDLEY_DIAGNOSTIC_POP
         #define JSON_HAS_CPP_20
         #define JSON_HAS_CPP_17
         #define JSON_HAS_CPP_14
-    #elif (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
+    #elif (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 + 0 == 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)
+    #elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 + 0 == 1)
         #define JSON_HAS_CPP_14
     #endif
     // the cpp 11 flag is always specified because it is the minimal required version