When constructing a new wall to optimize insulation value is it acceptable to install 2 inch foam board on the inside of the wall in addition to the fiberglass batts between studs?

2" of foam is not very vapor permeable, so from that point of view it makes sense to have it on the inside of walls in cold climates, and people did used to do this in the eighties, but all the current literature says that foam must be used on the outside, with a more permeable vapor barrier on the inside. See BUILDERS GUIDE TO COLD CLIMATES by Joseph Lstiburek.