Error conversion from const ClassName reference to long long int is ambiguous

[emiliogq]

I'm using Google Mock 1.8.0, and when trying to mock an interface which has some methods that receives some const className references as parameters, I get the following error:

/usr/include/gtest/internal/gtest-internal.h: In instantiation of ‘const bool testing::internal::ImplicitlyConvertible<const ClassName&, long long int>::value’:
/usr/include/gtest/gtest-printers.h:207:73:   required from ‘std::basic_ostream<_CharT, _Traits>& testing::internal2::operator<<(std::basic_ostream<_CharT, _Traits>&, const T&) [with Char = char; CharTraits = std::char_traits<char>; T = ClassName]’
/usr/include/gtest/gtest-printers.h:249:7:   required from ‘void testing_internal::DefaultPrintNonContainerTo(const T&, std::ostream*) [with T = ClassName; std::ostream = std::basic_ostream<char>]’
/usr/include/gtest/gtest-printers.h:439:49:   required from ‘void testing::internal::DefaultPrintTo(testing::internal::IsNotContainer, testing::internal::false_type, const T&, std::ostream*) [with T = ClassName; testing::internal::IsNotContainer = char; testing::internal::false_type = testing::internal::bool_constant<false>; std::ostream = std::basic_ostream<char>]’
/usr/include/gtest/gtest-printers.h:477:17:   required from ‘void testing::internal::PrintTo(const T&, std::ostream*) [with T = ClassName; std::ostream = std::basic_ostream<char>]’
/usr/include/gtest/gtest-printers.h:707:12:   required from ‘static void testing::internal::UniversalPrinter<T>::Print(const T&, std::ostream*) [with T = ClassName; std::ostream = std::basic_ostream<char>]’
/usr/include/gtest/gtest-printers.h:856:30:   [ skipping 3 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/usr/include/gmock/gmock-matchers.h:747:47:   required from ‘static void testing::internal::TuplePrefix<N>::ExplainMatchFailuresTo(const MatcherTuple&, const ValueTuple&, std::ostream*) [with MatcherTuple = std::tuple<testing::Matcher<const long unsigned int&>, testing::Matcher<const unsigned int&>, testing::Matcher<const ClassName&>, testing::Matcher<const long unsigned int&>, testing::Matcher<RTDB_WRITE_PARAMS*> >; ValueTuple = std::tuple<const long unsigned int&, const unsigned int&, const ClassName&, const long unsigned int&, RTDB_WRITE_PARAMS*>; long unsigned int N = 5; std::ostream = std::basic_ostream<char>]’
/usr/include/gmock/gmock-matchers.h:813:71:   required from ‘void testing::internal::ExplainMatchFailureTupleTo(const MatcherTuple&, const ValueTuple&, std::ostream*) [with MatcherTuple = std::tuple<testing::Matcher<const long unsigned int&>, testing::Matcher<const unsigned int&>, testing::Matcher<const ClassName&>, testing::Matcher<const long unsigned int&>, testing::Matcher<RTDB_WRITE_PARAMS*> >; ValueTuple = std::tuple<const long unsigned int&, const unsigned int&, const ClassName&, const long unsigned int&, RTDB_WRITE_PARAMS*>; std::ostream = std::basic_ostream<char>]’
/usr/include/gmock/gmock-spec-builders.h:1117:35:   required from ‘void testing::internal::TypedExpectation<F>::ExplainMatchResultTo(const ArgumentTuple&, std::ostream*) const [with F = void(const long unsigned int&, const unsigned int&, const ClassName&, const long unsigned int&, RTDB_WRITE_PARAMS*); testing::internal::TypedExpectation<F>::ArgumentTuple = std::tuple<const long unsigned int&, const unsigned int&, const ClassName&, const long unsigned int&, RTDB_WRITE_PARAMS*>; std::ostream = std::basic_ostream<char>]’
/usr/include/gmock/gmock-spec-builders.h:1763:40:   required from ‘void testing::internal::FunctionMockerBase<F>::PrintTriedExpectationsLocked(const ArgumentTuple&, std::ostream*) const [with F = void(const long unsigned int&, const unsigned int&, const ClassName&, const long unsigned int&, RTDB_WRITE_PARAMS*); testing::internal::FunctionMockerBase<F>::ArgumentTuple = std::tuple<const long unsigned int&, const unsigned int&, const ClassName&, const long unsigned int&, RTDB_WRITE_PARAMS*>; std::ostream = std::basic_ostream<char>]’
/usr/include/gmock/gmock-spec-builders.h:1739:5:   required from ‘void testing::internal::FunctionMockerBase<F>::FormatUnexpectedCallMessageLocked(const ArgumentTuple&, std::ostream*, std::ostream*) const [with F = void(const long unsigned int&, const unsigned int&, const ClassName&, const long unsigned int&, RTDB_WRITE_PARAMS*); testing::internal::FunctionMockerBase<F>::ArgumentTuple = std::tuple<const long unsigned int&, const unsigned int&, const ClassName&, const long unsigned int&, RTDB_WRITE_PARAMS*>; std::ostream = std::basic_ostream<char>]’
/usr/include/gmock/gmock-spec-builders.h:1689:13:   required from ‘const testing::internal::ExpectationBase* testing::internal::FunctionMockerBase<F>::UntypedFindMatchingExpectation(const void*, const void**, bool*, std::ostream*, std::ostream*) [with F = void(const long unsigned int&, const unsigned int&, const ClassName&, const long unsigned int&, RTDB_WRITE_PARAMS*); std::ostream = std::basic_ostream<char>]’
/usr/include/gmock/gmock-spec-builders.h:1679:34:   required from here
/usr/include/gtest/internal/gtest-internal.h:892:20: error: conversion from ‘const ClassName’ to ‘long long int’ is ambiguous
  892 |       sizeof(Helper(ImplicitlyConvertible::MakeFrom())) == 1;
      |             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ./src/rtdb/rtdb_impl.hpp:6,
                 from ./src/rtdb/rtdb.hpp:4,
                 from ./test/unit_tests/rtdb/rtdb_test.hpp:3,
                 from ./test/unit_tests/rtdb/rtdb_test.cpp:1:
ClassName.h:105:16: note: candidate: ‘ClassName::operator int() const’
  105 |         PUBLIC operator int() const;
      |                ^~~~~~~~
ClassName.h:106:16: note: candidate: ‘ClassName::operator char() const’
  106 |         PUBLIC operator char() const;
      |                ^~~~~~~~
ClassName.h:107:16: note: candidate: ‘ClassName::operator short int() const’
  107 |         PUBLIC operator short() const;
      |                ^~~~~~~~
ClassName.h:111:16: note: candidate: ‘ClassName::operator unsigned int() const’
  111 |         PUBLIC operator unsigned int() const;
      |                ^~~~~~~~
ClassName.h:112:16: note: candidate: ‘ClassName::operator unsigned char() const’
  112 |         PUBLIC operator unsigned char() const;
      |                ^~~~~~~~
ClassName.h:113:16: note: candidate: ‘ClassName::operator short unsigned int() const’
  113 |         PUBLIC operator unsigned short() const;
      |                ^~~~~~~~
ClassName.h:117:16: note: candidate: ‘ClassName::operator float() const’
  117 |         PUBLIC operator float() const;
      |                ^~~~~~~~
ClassName.h:118:16: note: candidate: ‘ClassName::operator double() const’
  118 |         PUBLIC operator double() const;
      |                ^~~~~~~~

I'm using the old style mock methods MOCK_METHODn.

I did not find anything related in gMock documentation.

Does anybody how to sort it out? Just to let you know, the ClassName type is a type from an external library that I cannot modify.

Thanks in advance,