internal: use ControlFlow in "extract function" assist

[dzvon]

Fixes #10272

[Veykril]

There is one slight problem here, ControlFlow isn't in the prelude so this needs to add an import to the module in this case. See the replace_qualified_name_with_use assist for an example on how to do this, it uses ImportScope::find_insert_use_container_with_macros and insert_use to do the job.

For this to then also work in unit tests you will need to add a //- minicore: try directive to the top of the relevant tests fixtures. Look at some other tests in the extract function module which should already be using minicore for some things to see what I mean.

[lnicola]

@dzvon do you need help with @Veykril's remark?

[dzvon]

I need help.

In replace_qualified_name_with_use, the variable scope is built as this.

    let scope = ImportScope::find_insert_use_container_with_macros(path.syntax(), &ctx.sema)?;

But how should I do in this case? What arguments should I pass into find_insert_use_container_with_macros?

I'm sorry, I have many concepts that are not clear to me :(. Thank you for your time and suggestion.

[Veykril]

No problem, you can always ask when something's not clear.

The arguments passed to to find_insert_use_container_with_macros are the node from where we should look for a module in its ancestors and the semantics.
So in this case you can just pass the node variable defined on line 70 in the extract_function file, that should work fine for this use case as that's a node in the module we are doing our edits in.

[Veykril]

Ah right use insertion logic requires mutable node edits. So this is a bit more tricky to get the edit out of as extract_function works with text based edits currently, something we probably want to change first.

I can take a look at doing that first, then you can rebase your changes on top of that if you'd like.

[dzvon]

@Veykril Thanks so much for your explanation. I've finished the import job. Could you give it a review again if you have time? :)

[Veykril]

Lgtm thanks!
bors r+

[bors]

Build succeeded:

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