"Inherent" "impls" save-analysis have empty "value"

[asutherland]

For a rust impl block like impl Loader {...}, the current nightly toolchain generates an impls entry that has a span that references the position of "Loader" in the source file, but the value is the empty string "".

As a particular example, https://github.com/mozsearch/mozsearch/blob/7b87459eea1c0a24beb362b7627960260185034b/tests/tests/files/simple.rs#L36 produces the following prettified impls item:

        {
            "span": {
                "byte_start": 748,
                "column_end": 12,
                "column_start": 6,
                "byte_end": 754,
                "line_end": 36,
                "file_name": "simple.rs",
                "line_start": 36
            },
            "parent": null,
            "kind": "Inherent",
            "children": [
                {
                    "index": 27,
                    "krate": 0
                },
                {
                    "index": 28,
                    "krate": 0
                },
                {
                    "index": 29,
                    "krate": 0
                },
                {
                    "index": 30,
                    "krate": 0
                },
                {
                    "index": 31,
                    "krate": 0
                }
            ],
            "value": "",
            "attributes": [],
            "sig": null,
            "id": 1,
            "docs": ""
        }

The context in which I'm concerned about this is for https://github.com/mozsearch/mozsearch. The rust language indexer uses rls to load the analysis data and processes it at a low level. I've hacked around the issue by extracting the contents of the span manually, but it seems useful to include the value.

Suggested label:A-save-analysis

[jyn514]

Save-analysis has been removed from the compiler.