Document reference search for constructiors/initializations

[umanwizard]

struct S {
    pub x: usize,
}

fn print_s(s: S) {
    println!("{}", s.x)
}

fn main() {
    let s = S { x: 42 };
    print_s(s);
}

"find references" on S in the above program will find both the usage of S in the type of the parameter to print_s, as well as the use of S in the instantiation of s in main. However, I often want to see all the places where a struct is created, without having to hunt through the list of all references for those specific ones.

[Veykril]

We actually already have this, though rather obsure(and possibly not really documented).
If you invoke reference search with $0 being the cursor like

struct S$0 {
    pub x: usize,
}

fn print_s(s: S) {
    println!("{}", s.x)
}

fn main() {
    let s = S { x: 42 };
    print_s(s);
}

(that is the cursor at the far end of the definition's ident)
you will get all constructor usages returned. The UX is obviously not really that great but we are somewhat limited by the language server protocol in this regard here.

Nevertheless we should document this behaviour better, assuming we don't yet.

[umanwizard]

The UX is obviously not really that great but we are somewhat limited by the language server protocol in this regard here.

Doesn't rust-analyzer have many extensions to the LSP already?

I could imagine r-a decides to supports thi, and then upstreams a proposal to the folks maintaining LSP (I guess Microsoft). Is this not a good model for how the process works?

In the meantime, thanks for the workaround.

[Veykril]

The main problem here is the question how to even expose this, we could make an extension out of this but that would require each client to somehow expose this special search as well. And in VSCode for example I don't think there is a decent way to offer more "kinds" of reference searches than the default.

[umanwizard]

The workaround doesn't work for me on version 04f03a360 2021-11-02 dev. It still finds all the references. Relevant parts of the server/client communication below:

[Trace - 12:37:12 PM] Sending request 'textDocument/references - (1396)'.
Params: {
  "textDocument": {
    "uri": "file:///Users/brennan/test_rust/src/main.rs"
  },
  "position": {
    "line": 0,
    "character": 8
  },
  "context": {
    "includeDeclaration": false
  }
}


[Trace - 12:37:12 PM] Received response 'textDocument/references - (1396)' in 1ms.
Result: [
  {
    "range": {
      "end": {
        "character": 15,
        "line": 4
      },
      "start": {
        "character": 14,
        "line": 4
      }
    },
    "uri": "file:///Users/brennan/test_rust/src/main.rs"
  },
  {
    "range": {
      "end": {
        "character": 13,
        "line": 9
      },
      "start": {
        "character": 12,
        "line": 9
      }
    },
    "uri": "file:///Users/brennan/test_rust/src/main.rs"
  }
]

[umanwizard]

The main problem here is the question how to even expose this, we could make an extension out of this but that would require each client to somehow expose this special rename as well. And in VSCode for example I don't think there is a decent way to offer more "kinds" of renames than the default.

Did you mean to leave this comment on my other issue, #10713 ?

[Veykril]

Ah my bad, I meant after the last character, not on the last(So in this case the whitespace char after the identifier).

Did you mean to leave this comment on my other issue, #10713 ?

Ah I typed rename by accident, meant reference search of course.

[Veykril]

Wrong again, its on the { char apparently(I rarely used this myself and with no docs I actually had to go check 😅)
So

struct S $0{
   ...
}

should show you all constructor usages, same applies for ( and ; for the different struct and enum variant variations.

[umanwizard]

Thanks, that works.