AST support : Context sensitive auto-completions for import module names

[rundis]

Summary

When the user has started an import declaration, with the cursor in the position where you should provide a module name for the import, an editor should be able to provide a list of applicable module names.

Discussion/Challenges

1. For this feature to work, you need to be aware of all project modules including modules from 3rd party dependencies (+ default imports). This might be out of scope for AST support as such.
2. For this too work at all, the AST would have to support being in an illegal state

Details

Let's say I've imported HTML and I'm in a module where everything is in a legal state, I then write

import Ht - I should now get a suggestion of Html, Html.App etc

• Need to be able to list all import declaration nodes, to be able to filter dupes