-- ASSUME: left-biased union

newtypesTypeDefs :: Newtypes -> M.NameMap DataInfo 
newtypesTypeDefs (Newtypes m)
  = m
newtypesTypeDefs :: Newtypes -> M.NameMap DataInfo
newtypesTypeDefs (Newtypes m)
  = m
newtypesTypeDefs (Newtypes m)
  = m