Does unused imports support `@_exported`?

[josh-arnold-1]

Hello,

How hard would it be for this unused imports script to support the usage of @_exported?

For example, say I have a module X that does this:

// My custom module `X`

@_exported import SwiftUI

Then in some other module, Y, we reference the exported module, but no symbols in the actual module `X:

// Inside module `Y`

import X

print(String(describing: Text("Hello world")) // usage of SwiftUI, but no usage of module `X` symbols

Would the unused imports job remove import X because it thinks its "unused", when in reality, its exported symbols/module is still referenced, therefore it shouldn't be removed?

swift-index-store/Sources/unused-imports/main.swift

Line 26 in 9cd7ac9

let alwaysKeepImports: Set<String>

Any help or guidance would be greatly appreciated, thanks!

[keith]

i looked at this at one point a few years ago but don't really recall where i ended up. we weren't using those heavily at the time so we mostly sidestepped this issue. i imagine it is possible to do by keeping the list of exported imports in some sort of graph (im not sure how transitive exported imports work) and cross checking those