clang 6.0 compilation error

[Yanpas]

            ^
.../src/json11.cpp:157:24:error:
      invalid operands to binary expression ('nullptr_t' and 'nullptr_t')
  ...m_value < static_cast<const Value<tag, T> *>(other)->m_value;
     ~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.../src/json11.cpp:213:5: note:
      in instantiation of member function
      'json11::Value<json11::Json::NUL, nullptr_t>::less' requested here
    JsonNull() : Value(nullptr) {}
    ^
1 error generated.

[Yanpas]

Patch to fix it:

@@ -208,7 +208,7 @@
     explicit JsonObject(Json::object &&value)      : Value(move(value)) {}
 };

-class JsonNull final : public Value<Json::NUL, std::nullptr_t> {
+class JsonNull final : public Value<Json::NUL, void*> {
 public:
     JsonNull() : Value(nullptr) {}
 };

[artwyman]

I think you're using an older version of json11 (the line numbers in your error message don't match up with the latest master). The issue you mentioned was already fixed in alternative way using the NullStruct helper: https://github.com/dropbox/json11/blob/master/json11.cpp#L220 If you pull the latest you should be all set.