Fix incorrect inlining of functions that come from MBE macros

[evertedsphere]

Partial fix for #16471.

As a reminder, there are two issues there:

1. missing whitespace in parameter types (the first test)
2. the self parameter not being replaced by this in the function body (the second test)

The first part is fixed in this PR. See this comment for the second.

[lnicola]

Rebasing should fix the CI.

[evertedsphere]

It looks like when the function body comes from a macro, usages_for_locals can't find the self parameter in it and so the renaming fails here:

rust-analyzer/crates/ide-assists/src/handlers/inline_call.rs

Lines 361 to 370 in 57a4542

	if let Some(self_local) = params[0].2.as_local(sema.db) {
	usages_for_locals(self_local)
	.filter_map(|FileReference { name, range, .. }| match name {
	FileReferenceNode::NameRef(_) => Some(body.syntax().covering_element(range)),
	_ => None,
	})
	.for_each(|usage| {
	ted::replace(usage, &this());
	});
	}

Specifically, in my second test (at the end of the file), we have

        self.value.$0hash2(state) // function comes from macro, fails to inline

but, as can be seen from other tests, a small change makes it pass:

        self.value.$0write2_u64(state) // function was written by hand, inlines correctly

Perhaps there is some kind of analysis that needs to be run on the function body if it comes from a macro so it is "parsed" into a syntax tree instead of being "opaque" like it seems to be here...?

[Veykril]

The usage only exists in a macro expansion so usage search can't find it. That is currently expected and non-trivial to fix as we can't look through all macro expansions that there are for obvious performance reasons. We could special case this search for locals as the scope of macro expansions is contained to the body the local belongs to, implementing that is already tricky though I believe.

[evertedsphere]

@Veykril would you be okay with me removing the second test and merging the other fix for now then? I can try to do the other one separately.

[Veykril]

That's fine yes

[Veykril]

That clippy issue should be fixed on master already, thanks!
@bors r+

[bors]

📌 Commit 18be556 has been approved by Veykril

It is now in the queue for this repository.

[bors]

⌛ Testing commit 18be556 with merge aa97edb...

[bors]

☀️ Test successful - checks-actions
Approved by: Veykril
Pushing aa97edb to master...