Invoking derived default() for tuple struct declared in function produces "Expected 1 argument, found 0"

[TedDriggs]

rust-analyzer version: 0.2.449

fn repro() {
    #[derive(Default)]
    struct EvidenceVisitor(String);
    let mut evidence_visitor = EvidenceVisitor::default();
}

This puts an error spanning EvidenceVisitor::default() which says "Expected 1 argument, found 0"

Adding a second member updates the error to "Expected 2 arguments, found 0"

Changing to an explicit impl Default for EvidenceVisitor doesn't change the error.

Changing to a unit struct or named struct makes the error disappear.

Moving the struct declaration outside the function body makes the error disappear. In the real code, I have the struct inside the function declaration because the whole function is cfg-gated, but the repro doesn't depend on conditional compilation.

[lnicola]

Duplicate of #1559.

[TedDriggs]

Ah, sorry. I looked for the error I got and found #5502 but didn't find that one.

[flodiebold]

Hmm there seems to be something going wrong with the name resolution there though, i.e. it looks like we resolve the EvidenceVisitor::default to the EvidenceVisitor constructor? We do have some basic support for function-local things which may be going wrong here, so I think it's worth checking whether there's something additional going on.

I.e. I'd expect EvidenceVisitor::default to not resolve at all, but then we wouldn't be emitting an error. It'd be interesting to see if the bug happens if the type is defined outside the function, but doesn't derive Default at all.

[jonas-schievink]

This no longer occurs, but we still don't support local impls properly

[jonas-schievink]

This is all fixed now