No signature help returned at ':'

[gfreezy]

This test should pass.

#[test]
fn test_enum_in_nested_method_in_lambda() {
    check(
        r#"
enum A {
    A,
    B
}

fn bar(_: A) { }

fn main() {
    let foo = Foo;
    std::thread::spawn(move || { bar(A:$0) } );
}
"#,
        expect![[r#"
                fn bar(_: A)
                (<_: A>)
            "#]],
    );
}

Related ast is as below:

              BLOCK_EXPR@413..436
                L_CURLY@413..414 "{"
                WHITESPACE@414..423 "\n        "
                EXPR_STMT@423..428
                  CALL_EXPR@423..428
                    PATH_EXPR@423..426
                      PATH@423..426
                        PATH_SEGMENT@423..426
                          NAME_REF@423..426
                            IDENT@423..426 "bar"
                    ARG_LIST@426..428
                      L_PAREN@426..427 "("
                      PATH_EXPR@427..428
                        PATH@427..428
                          PATH_SEGMENT@427..428
                            NAME_REF@427..428
                              IDENT@427..428 "A"
                EXPR_STMT@428..429
                  ERROR@428..429
                    COLON@428..429 ":"   <-------- here
                ERROR@429..430
                  R_PAREN@429..430 ")"
                WHITESPACE@430..435 "\n    "
                R_CURLY@435..436 "}"

[bjorn3]

bar(A:$0)

This is not valid rust syntax. You need to remove the :.

[lnicola]

Yeah, it works with both A and A::.

[gfreezy]

Screen.Recording.2021-09-07.at.2.02.06.PM.mov

[gfreezy]

The signature flips when typing A, A:, A::. It's disturbing.

It always show the outer function signature when the cursor is at an invalid syntax node instead of the current function.

[lnicola]

Interestingly, I don't get the thread::spawn docs:

signature.mp4

EDIT:

[gfreezy]

You need to trigger the bar signature first.
It seems to be the vscode behavior. When language server returns empty signature, vscode show the previous one.

input bar( => bar signature => input A: => spawn signature => input A:: => bar signature

[lnicola]

Nope, I still don't see it. But I do get your point.

[gfreezy]

rust-analyzer version: 3dae94bf2 2021-09-07 nightly

vscode

Version: 1.60.0
Commit: e7d7e9a9348e6a8cc8c03f877d39cb72e5dfb1ff
Date: 2021-09-01T10:54:53.442Z
Electron: 13.1.8
Chrome: 91.0.4472.164
Node.js: 14.16.0
V8: 9.1.269.39-electron.0
OS: Darwin x64 20.6.0

[lnicola]

Yeah, I'm on the same Code version. Does it happen with the code in your test?

[gfreezy]

Yeah, I'm on the same Code version. Does it happen with the code in your test?

enum A {
    A,
    B
}

fn bar(_: A) { }

fn main() {
    let foo = Foo;
    std::thread::spawn(move || { 
        bar(A:$0) 
    } // braces is needed 
    );
}

[lnicola]

Ah, right. My rustfmt ate those.