------- Comment #4 from redi at gcc dot gnu dot org 2009-12-04 17:31 ------- (In reply to comment #3) > the pb is on line : > template < typename X , typename XT2 =T , typename X2 = typename XT2 :: > X > SMART(SMART<X> & value) : data(value.CastUp) {} ;
I don't understand, that line did not appear in your original report. The error you originally posted is caused by the problem I pointed out. > if i replace the line by > > template < typename XT2 = T , typename X2 = typename XT2 :: X > > > SMART(SMART<X2> & value) : data(value.CastUp()) {} ; > the constructor is find but i want an unherited constraint on X => X2 is > T::X I have no idea what an unherited constraint is. > sh-3.2$ gcc-4.5-20091126/bin/g++ -std=c++0x -c main.cc > main.cc: In constructor SMART<T>::SMART(SMART<X2>&) [with XT2 = B, X2 = > A, T = B]: > main.cc:45:13: instantiated from here > main.cc:17:118: erreur: no matching function for call to > SMART<A>::CastUp() CastUp is a template function but the template parameters cannot be deduced, so you need to say value.CastUp<foo>() for some type "foo" The bug is in your code, not GCC. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42272