eliminates shadow warnings from filter
eliminates shadow warnings from filter

jkhoogland/cppitertools,jkhoogland/cppitertools,jkhoogland/cppitertools,ryanhaining/cppitertools,tempbottle/cppitertools,ryanhaining/cppitertools,tempbottle/cppitertools,tempbottle/cppitertools,ryanhaining/cppitertools