warn when a global is shadowed about luacheck HOT 3 CLOSED

Good idea, shadowing a global can lead to same issues as shadowing locals. It can be deliberate when "localizing" a global, e.g. local type = type, but that case is trivial to detect. I'll implement this in the next minor version. Thanks!

from luacheck.

Implementation delayed as it requires some refactoring: the checker needs to have information about existing globals, or else it would have to save information about all declared locals so that then the filter could leave only necessary warnings (separation into two steps is needed for caching and parallel checking.)

from luacheck.

I've decided to not implement this because global localization is a popular and flexible idiom, it's not always in the top level scope and it doesn't always use global of the same name on rhs. So either there would be false positives or heuristics to avoid them would be too complex. I think that a better and more general way to detect this is type inference, whenever it gets implemented.

from luacheck.