Unable to iterate json: "ambiguous overload for operator!="

[torridstoic]

I am failing to compile when attempting to iterate a json object. Code:
void parse(const std::string& jsonStr) { const auto jsonObj = nlohmann::json::parse(jsonStr); for (const auto& entry : jsonObj.items()) {} }

I tried both the range-based for example and the stl-iter example from the README's "STL-like access" section: both attempts gave the same compiler error.

I'll post the full output in a response, but here is the error itself:
error: ambiguous overload for ‘operator!=’ (operand types are ‘const nlohmann::detail::iter_impl<const nlohmann::basic_json<> >’ and ‘const nlohmann::detail::iter_impl<const nlohmann::basic_json<> >’)
The first candidate is std::rel_ops::operator!=, and the second is nlohmann::detail::iter_impl::operator!=.

OS is RHEL 8.7, compiler GCC 8.5.0, C++17

[torridstoic]

Full output, including compile args:

Error processing Command:
g++ -ggdb -gdwarf-3 -fPIC -ggdb -ffloat-store -iquote/workspaces/src/c++/lib-src/Json -D_REENTRANT -D_POSIX_PTHREAD_SEMANTICS -DUNIX -Wall -Wextra -Wlogical-op -Wformat=2 -Wformat-signedness -Wsuggest-final-types -Wsuggest-final-methods -Wcast-align -Wwrite-strings -Wno-error=format-y2k -Wno-error=format-nonliteral -Wmissing-include-dirs -fdiagnostics-color=always -c -Werror -Wno-comment -Wno-missing-field-initializers -Wno-unused-parameter -Wunused-macros -Wno-error=sign-compare -Wno-error=conversion -Wno-error=float-conversion -Wno-error=sign-conversion -std=c++17 /workspaces/src/c++/lib-src/Json/JsonMsgParser.cc -o /workspaces/src/c++/lib-src/Json/linux-64/JsonMsgParser.o -MMD -MT /workspaces/src/c++/lib-src/Json/linux-64/JsonMsgParser.o
Output:
PATH=/vscode/vscode-server/bin/linux-x64/1a5daa3a0231a0fbba4f14db7ec463cf99d7768e/bin/remote-cli:/usr/local/lib/nodejs/node-v10.16.0-linux-x64/bin:/usr/share/Modules/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/home/default/.local/bin:/home/default/bin
LD_LIBRARY_PATH=
In file included from /workspaces/src/c++/lib-src/Json/JsonMsgParser.hh:9,
from /workspaces/src/c++/lib-src/Json/JsonMsgParser.cc:7:
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp: In instantiation of �bool nlohmann::detail::iteration_proxy_value::operator!=(const nlohmann::detail::iteration_proxy_value&) const [with IteratorType = nlohmann::detail::iter_impl<const nlohmann::basic_json<> >]�:
/workspaces/src/c++/lib-src/Json/JsonMsgParser.cc:221:125: required from here
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:4377:23: error: ambiguous overload for �operator!=� (operand types are �const nlohmann::detail::iter_impl<const nlohmann::basic_json<> >� and �const nlohmann::detail::iter_impl<const nlohmann::basic_json<> >�)
return anchor != o.anchor;
~~~~~~~^~~~~~~~~~~
In file included from /workspaces/src/c++/lib-src/Json/JsonMsgParser.hh:9,
from /workspaces/src/c++/lib-src/Json/JsonMsgParser.cc:7:
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:11861:10: note: candidate: �bool nlohmann::detail::iter_impl::operator!=(const IterImpl&) const [with IterImpl = nlohmann::detail::iter_impl<const nlohmann::basic_json<> >; typename std::enable_if<(std::is_same<IterImpl, nlohmann::detail::iter_impl >::value || std::is_same<IterImpl, nlohmann::detail::iter_impl<typename std::conditional<std::is_const<_Tp>::value, typename std::remove_const<_Tp>::type, const BasicJsonType>::type> >::value), std::nullptr_t>::type = nullptr; BasicJsonType = const nlohmann::basic_json<>]�
bool operator!=(const IterImpl& other) const
^~~~~~~~
In file included from /usr/include/c++/8/utility:69,
from /usr/include/c++/8/algorithm:60,
from /workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:46,
from /workspaces/src/c++/lib-src/Json/JsonMsgParser.hh:9,
from /workspaces/src/c++/lib-src/Json/JsonMsgParser.cc:7:
/usr/include/c++/8/bits/stl_relops.h:87:7: note: candidate: �bool std::rel_ops::operator!=(const _Tp&, const _Tp&) [with _Tp = nlohmann::detail::iter_impl<const nlohmann::basic_json<> >]�
operator!=(const _Tp& __x, const _Tp& __y)
^~~~~~~~
In file included from /workspaces/src/c++/lib-src/Json/JsonMsgParser.hh:9,
from /workspaces/src/c++/lib-src/Json/JsonMsgParser.cc:7:
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp: In instantiation of �bool nlohmann::detail::json_sax_dom_callback_parser::end_object() [with BasicJsonType = nlohmann::basic_json<>]�:
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:10904:33: required from �bool nlohmann::detail::parser<BasicJsonType, InputAdapterType>::sax_parse_internal(SAX*) [with SAX = nlohmann::detail::json_sax_dom_callback_parser<nlohmann::basic_json<> >; BasicJsonType = nlohmann::basic_json<>; InputAdapterType = nlohmann::detail::iterator_input_adapter<const char*>]�
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:10797:13: required from �void nlohmann::detail::parser<BasicJsonType, InputAdapterType>::parse(bool, BasicJsonType&) [with BasicJsonType = nlohmann::basic_json<>; InputAdapterType = nlohmann::detail::iterator_input_adapter<const char*>]�
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:20835:9: required from �static nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType> nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::parse(IteratorType, IteratorType, nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::parser_callback_t, bool, bool) [with IteratorType = const char*; ObjectType = std::map; ArrayType = std::vector; StringType = std::__cxx11::basic_string; BooleanType = bool; NumberIntegerType = long int; NumberUnsignedType = long unsigned int; NumberFloatType = double; AllocatorType = std::allocator; JSONSerializer = nlohmann::adl_serializer; BinaryType = std::vector; nlohmann::basic_json<ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType>::parser_callback_t = std::function<bool(int, nlohmann::detail::parse_event_t, nlohmann::basic_json<>&)>]�
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:21900:42: required from here
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:6148:58: error: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second: [-Werror]
for (auto it = ref_stack.back()->begin(); it != ref_stack.back()->end(); ++it)
In file included from /usr/include/c++/8/utility:69,
from /usr/include/c++/8/algorithm:60,
from /workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:46,
from /workspaces/src/c++/lib-src/Json/JsonMsgParser.hh:9,
from /workspaces/src/c++/lib-src/Json/JsonMsgParser.cc:7:
/usr/include/c++/8/bits/stl_relops.h:87:7: note: candidate 1: �bool std::rel_ops::operator!=(const _Tp&, const _Tp&) [with _Tp = nlohmann::detail::iter_impl<nlohmann::basic_json<> >]�
operator!=(const _Tp& __x, const _Tp& __y)
^~~~~~~~
In file included from /workspaces/src/c++/lib-src/Json/JsonMsgParser.hh:9,
from /workspaces/src/c++/lib-src/Json/JsonMsgParser.cc:7:
/workspaces/src/c++/lib-src/Json/jsoncpp/json.hpp:11861:10: note: candidate 2: �bool nlohmann::detail::iter_impl::operator!=(const IterImpl&) const [with IterImpl = nlohmann::detail::iter_impl<nlohmann::basic_json<> >; typename std::enable_if<(std::is_same<IterImpl, nlohmann::detail::iter_impl >::value || std::is_same<IterImpl, nlohmann::detail::iter_impl<typename std::conditional<std::is_const<_Tp>::value, typename std::remove_const<_Tp>::type, const BasicJsonType>::type> >::value), std::nullptr_t>::type = nullptr; BasicJsonType = nlohmann::basic_json<>]�
bool operator!=(const IterImpl& other) const
^~~~~~~~
cc1plus: all warnings being treated as errors

[torridstoic]

Arrg: I spend days searching for an answer before giving up and asking here. Within an hour of posting, I found the problem and a solution: elsewhere in my codebase, I found using std::rel_ops::operator!=; std::rel_ops::operator>; std::rel_ops::operator<=; std::rel_ops::operator>=;

Removing these statements and replacing them with boost/operators.hpp in the affected class fixed my compile errors.