When generating code, the Thrift compiler has a "-strict" option that errors out for certain warnings. Specifically, it errors out when there are implicit field keys:
I think that it would be useful to add "-strict" to the arguments for Thrift code generation. It would prevent the introduction of new compatibility issues, because the command would fail rather than generating a warning that is easy to miss.
The current Thrift files already work with -strict, so this should be a painless thing.