GCC6: implicit casting triggers error

[Sandro Mani]

Hi

Med builds are failing with

medfile_int_wrap.cc:11272:30: error: no matching function for call to
'std::vector<double, std::allocator<double>
>::erase(SwigValueWrapper<__gnu_cxx::__normal_iterator<double*,
std::vector<double, std::allocator<double> > > >&)'
    result = (arg1)->erase(arg2);


A standalone version which fails to compile (ignoring the fact that arg2 is not
initialized):

---------------------

#include <vector>

typedef double         med_float;

template<typename T> class SwigValueWrapper {
   struct SwigMovePointer {
     T *ptr;
     SwigMovePointer(T *p) : ptr(p) { }
     ~SwigMovePointer() { delete ptr; }
     SwigMovePointer& operator=(SwigMovePointer& rhs) { T* oldptr = ptr; ptr = 0;
delete oldptr; ptr = rhs.ptr; rhs.ptr = 0; return *this; }
   } pointer;
   SwigValueWrapper& operator=(const SwigValueWrapper<T>& rhs);
   SwigValueWrapper(const SwigValueWrapper<T>& rhs);
public:
   SwigValueWrapper() : pointer(0) { }
   SwigValueWrapper& operator=(const T& t) { SwigMovePointer tmp(new T(t));
pointer = tmp; return *this; }
   operator T&() const { return *pointer.ptr; }
   T *operator&() { return pointer.ptr; }
};

template <typename T> T SwigValueInit() {
   return T();
}

int main() {
   std::vector< med_float > arg1;
   SwigValueWrapper< std::vector< double >::iterator > arg2;
   arg1.erase(arg2);
};

---------------------

GCC 5 compiles the code. GCC6 seems to require an explicit cast, even though

std::vector<double>::iterator it = arg2;


works. GCC bug?

Thanks
asndro