CommandLine Manual: Writing a custom parser example broke

It looks like the "Writing a custom parser" example from the CommandLine
2.0 Library Manual is broke for 3.0+. This used to work with llvm-2.9.
When I try to compile it I get:

../include/llvm/Support/CommandLine.h:964:20: error: no viable
conversion from 'const FileSizeParser' to 'parser<unsigned>'

I fixed it by changing

struct FileSizeParser : public cl::basic_parser<unsigned> {


struct FileSizeParser : public cl::parser<unsigned> {

on 3.0