I believe that the defect is related to Subversion commit 57503 that was intended to remove a warning, but it has the side-effect of making the Phoenix actors always non-assignable regardless of the template parameters.

During my testing with GCC/Linux I was able to get your code to compile by commenting out line 143 of boost/spirit/home/phoenix/core/actor.hpp

Would you assist me by making the same change and posting your results? If this fixes your problem I shall raise a Trac issue and submit a patch for Phoenix.