settings.json

{
    "rust-analyzer.linkedProjects": [
        {
            "sysroot_src": "/home/matklad/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library",
            "crates": [
                {
                    "root_module": "src/main.rs",
                    "edition": "2018",
                    "deps": [],
                },
            ]
        }
    ]
}