Rustdoc JSON: Duplicated ID's in lists

[aDotInTheVoid]

          Looking at the output (of `tests/rustdoc-json/reexport/same_name_different_types.rs`), for some reason it's duplicating ID's in the output:

  "index": {
    "0:0:1588": {
      "crate_id": 0,
      "docs": null,
      "id": "0:0:1588",
      "inner": {
        "is_crate": true,
        "is_stripped": false,
        "items": [
          "0:1:1582",
          "0:4-0:2:1584",
          "0:4-0:3:1584",
          "0:4-0:2:1584",
          "0:4-0:3:1584",
          "0:5-0:2:1584",
          "0:5-0:3:1584",
          "0:5-0:2:1584",
          "0:5-0:3:1584"
        ]
      },
      "kind": "module",
      "name": "same_name_different_types"
    },

I'm not really sure whats causing this, but idealy it wouldn't happen, although I'd be willing to merge as is, as long as an issue gets created to follow up.

(Also, jsondoclint should probably catch this)

Originally posted by @aDotInTheVoid in #107766 (comment)

CC: #108163

[shogohida]

Hi @aDotInTheVoid, can I work on this? I searched a bit for the source code but I don't know where to start yet...

[aDotInTheVoid]

Your more than welcome to!

Convertion from clean to json for module's happens here, and it just passes of ID's coming from clean

rust/src/librustdoc/json/conversions.rs

Lines 302 to 304 in e7eaed2

	ModuleItem(m) => {
	ItemEnum::Module(Module { is_crate, items: ids(m.items, tcx), is_stripped: false })
	}

Clean makes it's modules here

rust/src/librustdoc/clean/mod.rs

Line 51 in e7eaed2

pub(crate) fn clean_doc_module<'tcx>(doc: &DocModule<'tcx>, cx: &mut DocContext<'tcx>) -> Item {

I'd start by adding debug! calls to see whats going on here. See the rustc dev guide for info on how the debug macros work for rustc. Feel free to ask questions on zulip if you have any

[GuillaumeGomez]

It was fixed in #108349.