Another fun idea is to make a "code denoiser". Removing noise (bugs) from your code. It's quite simple to synthetically inject lots of noise into code, simply

Another fun idea is to make a "code denoiser". Removing noise (bugs) from your code. It's quite simple to synthetically inject lots of noise into code, simply use the wrong variables, operators, numbers, structures, reverse statement ordering, transforming code at the AST level. Then you can learn mappings of bad code => good code! The same idea has worked for natural languages as well, correcting typos.