Problem in debugging templates. Build fails specifically for Linux GCC 7, GCC 6, GCC 5, GCC 4.9 error: template argument 1 is invalid

Question

My Travis is only failing for Linux GCC 7, GCC 6, GCC 5, GCC 4.9 with error

libs/astronomy/test/coordinate/equatorial_coord.cpp:22:57: error: template argument 1 is invalid
         RightAscension<double, quantity<bud::plane_angle>>
                                                         ^
libs/astronomy/test/coordinate/equatorial_coord.cpp:23:39: error: template argument 2 is invalid
                 ra(25.0 * bud::degrees);

Here is equatorial_cord.cpp

#define BOOST_TEST_MODULE equatorial_coord_test

#include <iostream>
#include <boost/units/io.hpp>
#include <boost/units/quantity.hpp>
#include <boost/units/systems/angle/degrees.hpp>
#include <boost/units/systems/si/plane_angle.hpp>
#include <boost/astronomy/coordinate/coord_sys/equatorial_coord.hpp>

#include <boost/test/unit_test.hpp>

using namespace boost::astronomy::coordinate;
using namespace boost::units;
using namespace boost::units::si;
namespace bud = boost::units::degree;
namespace bu = boost::units;

BOOST_AUTO_TEST_SUITE(angle)

    BOOST_AUTO_TEST_CASE(right_ascension) {
        //Create object of Right Ascension
        RightAscension<double, quantity<bud::plane_angle>>
                ra(25.0 * bud::degrees);

        //Check value
        BOOST_CHECK_CLOSE(ra.get_angle().value(), 25.0, 0.001);

        //Quantity stored as expected?
        BOOST_TEST((std::is_same<decltype(ra.get_angle()), quantity<bud::plane_angle>>::value));
    }

BOOST_AUTO_TEST_SUITE_END()

which includes and uses Equatorial_coord.hpp

#include <iostream>
#include <boost/units/io.hpp>
#include <boost/geometry/core/cs.hpp>
#include <boost/geometry/geometries/point.hpp>
#include <boost/units/systems/angle/degrees.hpp>
#include <boost/units/systems/si/plane_angle.hpp>
#include <boost/astronomy/coordinate/coord_sys/coord_sys.hpp>

namespace boost {
    namespace astronomy {
        namespace coordinate {

            namespace bu = boost::units;
            namespace bg = boost::geometry;
            namespace bud = boost::units::degree;

            //Right Ascension
            template
                    <
                            typename CoordinateType = double,
                            typename RightAscensionQuantity = bu::quantity<bu::si::plane_angle, CoordinateType>
                    >
            struct RightAscension {
            private:
                RightAscensionQuantity ra;
            public:
                RightAscension(){
                    ra = 0.0 * bu::si::radian;
                };

                RightAscension(RightAscensionQuantity const& _ra) : ra(_ra) {}

                RightAscensionQuantity get_angle() const{
                    return static_cast<RightAscensionQuantity>(ra);
                }

                void print() {
                    std::cout << "Right Ascension: " << ra;
                }
            };
...

It builds perfectly on my machine and I have tried some variation of code but I cannot understand what am I missing that builds are failing specifically for Linux GCC 7, GCC 6, GCC 5, GCC 4.9.

In this project, I have made many headers in a similar fashion but never faced such an issue. I will be grateful for any suggestions.

https://dev.azure.com/lpranam/lpranam/_build/results?buildId=392&view=logs&j=d5b3eaca-5133-5bed-7ece-a6421a4fcca5&t=9b0787b9-d206-5213-01a9-f3ff4bf8b6d6

Answer 1

There are multiple definitions of namespace bud = boost::units::degree; in the project which is causing the problem. Removing it from Equatorial_coord.hpp would do the magic for you.