It is possible with every kind of de-duplicating copy-pasted code. You need some boilerplate for the common template (not necessarily in the C++ sense), then so

It is possible with every kind of de-duplicating copy-pasted code. You need some boilerplate for the common template (not necessarily in the C++ sense), then some more boilerplate for its instantiations to replace the previously-copypasted blocks of code. Then the blocks weren't exactly identical, so the template (again, not necessarily C++) needs to gain placeholders/ifs and the instantiations need to fill them/provide conditions. If you do it with C++ templates using the traits machinery, it generates quite a lot of bloat. It is not a reason to never use these mechanisms, just to be wary of the costs.