Possible improvements

[JelleZijlstra]

A couple of things we should consider changing:

• Use __a and __b as the names, so we can catch name mangling bugs
• Constrain what kind of expressions appear in subscripts, so we generate less code like (1)[a] that will fail at runtime. I feel such code is less likely to be interesting, as the TypeError from the subscript could hide more interesting errors.
• In the function evaluation code from evaluate namespaces recursively, and function namespaces, too #2, first check how many arguments the function takes using inspect, and pass those arguments. That way, we get a bit more coverage of locals.

[JelleZijlstra]

Another one: the repro case from python/cpython#104619 actually crashed the evalserver with a RecursionError, because the function returned itself and we kept recursively calling it. We should put some limit on the recursive namespace evaluation.