added explicit instantiations of 'has_from_json' and 'has_to_json' for std_fs::path (#5209)

* added explicit instantiations of 'has_from_json' and 'has_to_json' for std_fs::path;
Signed-off-by: drcosmin <cosmin.dr@pm.me>

* Fixed amalgamation

Signed-off-by: drcosmin <cosmin.dr@pm.me>

---------

Signed-off-by: drcosmin <cosmin.dr@pm.me>

include/nlohmann/detail/conversions/from_json.hpp

diff --git a/include/nlohmann/detail/conversions/from_json.hpp b/include/nlohmann/detail/conversions/from_json.hpp
index 5a7cdb6..6506503 100644
--- a/include/nlohmann/detail/conversions/from_json.hpp
+++ b/include/nlohmann/detail/conversions/from_json.hpp
@@ -558,6 +558,11 @@
 }
 
 #if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
+
+// Workaround for MSVC 19.51 (and possibly later): in large in large cpp files, the compiler may fail to resolve with generic has_from_json (issue #4996)
+template<typename BasicJsonType>
+struct has_from_json<BasicJsonType, std_fs::path, void> : std::true_type {};
+
 template<typename BasicJsonType>
 inline void from_json(const BasicJsonType& j, std_fs::path& p)
 {

include/nlohmann/detail/conversions/to_json.hpp

diff --git a/include/nlohmann/detail/conversions/to_json.hpp b/include/nlohmann/detail/conversions/to_json.hpp
index 3626593..0e0fb46 100644
--- a/include/nlohmann/detail/conversions/to_json.hpp
+++ b/include/nlohmann/detail/conversions/to_json.hpp
@@ -450,6 +450,10 @@
 }
 #endif
 
+// Workaround for MSVC 19.51 (and possibly later): in large cpp files, the compiler may fail to resolve with generic has_to_json (issue #4996)
+template<typename BasicJsonType>
+struct has_to_json<BasicJsonType, std_fs::path, void> : std::true_type {};
+
 template<typename BasicJsonType>
 inline void to_json(BasicJsonType& j, const std_fs::path& p)
 {

single_include/nlohmann/json.hpp

diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index d2165e8..dec4811 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -5668,6 +5668,11 @@
 }
 
 #if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
+
+// Workaround for MSVC 19.51 (and possibly later): in large in large cpp files, the compiler may fail to resolve with generic has_from_json (issue #4996)
+template<typename BasicJsonType>
+struct has_from_json<BasicJsonType, std_fs::path, void> : std::true_type {};
+
 template<typename BasicJsonType>
 inline void from_json(const BasicJsonType& j, std_fs::path& p)
 {
@@ -6451,6 +6456,10 @@
 }
 #endif
 
+// Workaround for MSVC 19.51 (and possibly later): in large cpp files, the compiler may fail to resolve with generic has_to_json (issue #4996)
+template<typename BasicJsonType>
+struct has_to_json<BasicJsonType, std_fs::path, void> : std::true_type {};
+
 template<typename BasicJsonType>
 inline void to_json(BasicJsonType& j, const std_fs::path& p)
 {