Non-existing files from compiler_builtins are returned when searching symbols

[Frederick888]

I'm using rls 1.41.0 (5fde462 2020-02-21) with coc-rls in NeoVim.

When searching symbols, rls sometimes returns compiler_builtins files which don't really exist. For instance:

$ rls --cli
> symbol g
2: [
    SymbolInformation {
        name: "__gedf2",
        kind: Function,
        deprecated: None,
        location: Location {
            uri: "file:///cargo/registry/src/github.com-1ecc6299db9ec823/compiler_builtins-0.1.25/src/float/cmp.rs",
            range: Range {
                start: Position {
                    line: 148,
                    character: 22,
                },
                end: Position {
                    line: 148,
                    character: 29,
                },
            },
        },
        container_name: Some(
            "cmp",
        ),
    },
    SymbolInformation {
        name: "__gesf2",
        kind: Function,
        deprecated: None,
        location: Location {
            uri: "file:///cargo/registry/src/github.com-1ecc6299db9ec823/compiler_builtins-0.1.25/src/float/cmp.rs",
            range: Range {
                start: Position {
                    line: 119,
                    character: 22,
                },
                end: Position {
                    line: 119,
                    character: 29,
                },
            },
        },
        container_name: Some(
            "cmp",
        ),
    },

This causes coc to show a bunch of errors, while in VSCode I guess they are just silently ignored. I wonder whether these should be filtered out in the server's side or the clients'?