Unions with identical types in different cases don't work about cyclonedds-cxx HOT 1 CLOSED

RnR.zip

Hi Erik,

I am facing same problem as you mentioned above, when we try to build the attached idl file, we got the below errors:

/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1110:7: error:
static_assert failed due to requirement
'__detail::__variant::__exactly_once<std::__cxx11::basic_string,
DDS::Duration_t, DDS::Time_t, std::__cxx11::basic_string,
std::__cxx11::basic_string >' "T must occur exactly once in
alternatives"
static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/RnR.hpp:274:17: note:
in instantiation of function template specialization
'std::get<std::__cxx11::basic_string, DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >'
requested here
return std::getstd::string(m__u);
^
In file included from /home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/subscriber.cpp:21:
In file included from /home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/RnR.hpp:15:
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1091:7: error:
static_assert failed due to requirement
'__detail::__variant::__exactly_once<std::__cxx11::basic_string,
DDS::Duration_t, DDS::Time_t, std::__cxx11::basic_string,
std::__cxx11::basic_string >' "T must occur exactly once in
alternatives"
static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/RnR.hpp:283:17: note:
in instantiation of function template specialization
'std::get<std::__cxx11::basic_string, DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >'
requested here
return std::getstd::string(m__u);
^
/home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/RnR.hpp:293:10: error:
no viable overloaded '='
m__u = u;
~~~~ ^ ~
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1368:16: note:
candidate function not viable: no known conversion from
'const std::string' (aka 'const basic_string') to 'const
std::variant<DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >' for
1st argument
variant& operator=(const variant&) = default;
^
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1369:16: note:
candidate function not viable: no known conversion from
'const std::string' (aka 'const basic_string') to
'std::variant<DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >' for
1st argument
variant& operator=(variant&&) = default;
^
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1431:2: note:
candidate template ignored: requirement '18446744073709551615UL <
sizeof...(_Types)' was not satisfied [with _Tp = const
std::__cxx11::basic_string &]
operator=(_Tp&& __rhs)
^
In file included from /home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/subscriber.cpp:21:
/home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/RnR.hpp:303:10: error:
no viable overloaded '='
m__u = u;
~~~~ ^ ~
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1368:16: note:
candidate function not viable: no known conversion from 'std::string' (aka
'basic_string') to 'const std::variant<DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >' for
1st argument
variant& operator=(const variant&) = default;
^
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1369:16: note:
candidate function not viable: no known conversion from 'std::string' (aka
'basic_string') to 'std::variant<DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >' for
1st argument
variant& operator=(variant&&) = default;
^
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1431:2: note:
candidate template ignored: requirement '18446744073709551615UL <
sizeof...(_Types)' was not satisfied [with _Tp =
std::__cxx11::basic_string &]
operator=(_Tp&& __rhs)
^
In file included from /home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/subscriber.cpp:21:
/home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/RnR.hpp:331:10: error:
no viable overloaded '='
m__u = u;
~~~~ ^ ~
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1368:16: note:
candidate function not viable: no known conversion from
'const std::string' (aka 'const basic_string') to 'const
std::variant<DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >' for
1st argument
variant& operator=(const variant&) = default;
^
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1369:16: note:
candidate function not viable: no known conversion from
'const std::string' (aka 'const basic_string') to
'std::variant<DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >' for
1st argument
variant& operator=(variant&&) = default;
^
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1431:2: note:
candidate template ignored: requirement '18446744073709551615UL <
sizeof...(_Types)' was not satisfied [with _Tp = const
std::__cxx11::basic_string &]
operator=(_Tp&& __rhs)
^
In file included from /home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/subscriber.cpp:21:
/home/vivekp/ADLINK-CycloneDDS8/share/CycloneDDS-CXX/examples/rnr-manager/RnR.hpp:341:10: error:
no viable overloaded '='
m__u = u;
~~~~ ^ ~
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1368:16: note:
candidate function not viable: no known conversion from 'std::string' (aka
'basic_string') to 'const std::variant<DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >' for
1st argument
variant& operator=(const variant&) = default;
^
/usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/variant:1369:16: note:
candidate function not viable: no known conversion from 'std::string' (aka
'basic_string') to 'std::variant<DDS::Duration_t, DDS::Time_t,
std::__cxx11::basic_string, std::__cxx11::basic_string >' for
1st argument
variant& operator=(variant&&) = default;

Let me know when will we fix this issue.

With best regards,
Vivek

from cyclonedds-cxx.