package-level lint: unused, unexposed public members

[srawlins]

I'd like a lint rule that flags public library members (classes, top-level variables, typedefs, functions) and public class members (all the usual suspects) that are unused within their package, and not exposed from a library in the lib/ directory.

// lib/foo.dart

export 'src/foo.dart' show usedConstant;

// lib/src/foo.dart

// BAD
final unusedConstant = "CONSTANT";

final usedConstant = "CONSTANT";

[matanlurey]

I don't see how this is possible for the analyzer, it won't necessarily know the entire scope of imports.

[srawlins]

I thought the linter project had some aims to do package-level analysis? @pq is this done/feasible/planned?

[bwilkerson]

It isn't currently implemented. I'm not sure whether we're going to get there. But I do think we want to do this kind of analysis (and I have a prototype implementation that I've been using on some of our packages).

[pq]

Thanks for chiming in, @bwilkerson! Was just about to ping you. 😄

[chrisnorman7]

I'd like to add my support for this request too. I've been doing a lot of work with FFI bindings recently, and it would be nice to know what new functions ETC ffigen has created that I'm not yet using. Otherwise you have to go out and catalogue every function, and work out if you've already used it yet.

Unless I'm completely mis-writing bindings of course. That is more than possible.

[srawlins]

I had forgotten about my linter request here 😆 and in fact, I think this is beyond what the linter does these days...

I have an internal proposal for Whole World analysis, which would enfold this. I think there are some great benefits to Whole World analysis, and would like to prioritize the feature.