This plugin adds support for the new Roslyn-based C# language server introduced in the VS Code C# extension.

Requires at least Neovim 0.10

1. Navigate to https://dev.azure.com/azure-public/vside/_artifacts/feed/vs-impl to see the latest package feed for Microsoft.CodeAnalysis.LanguageServer
2. Locate the version matching your OS + Arch and click to open it. For example, Microsoft.CodeAnalysis.LanguageServer.linux-x64 matches Linux-based OS in x64 architecture. Note that some OS/Arch specific packages may have an extra version ahead of the "core" non specific package.
3. On the package page, click the "Download" button to begin downloading its .nupkg a. (Note, if you need to get a copyable link for the download you can obtain it on chrome by then opening the downloads page, right clicking the file just downloaded, and hitting "copy link address"
4. .nupkg files are basically zip archives. In the case of Linux, you can use unzip on the downloaded file to unpack it.
5. Copy the contents of <zip root>/content/LanguageServer/<yourArch/ to ~/.local/share/nvim/roslyn a. if you did it right, the file ~/.local/share/nvim/roslyn/Microsoft.CodeAnalysis.LanguageServer.dll should exist now (along with many other .dlls and etc in that dir). You can also specify a custom path to it in the setup function.
6. To test it is working, cd into the aforementioned roslyn directory and invoke dotnet Microsoft.CodeAnalysis.LanguageServer.dll --version. It should output server's version.

Install seblj/roslyn.nvim using your plugin manager.

Example:

require("roslyn").setup({
    config = {
        -- Here you can pass in any options that that you would like to pass to `vim.lsp.start`
        -- The only options that I explicitly override are, which means won't have any effect of setting here are:
        --     - `name`
        --     - `cmd`
        --     - `root_dir`
        --     - `on_init`
        --     - `handlers`
    },
    exe = vim.fs.joinpath(
        vim.fn.stdpath("data") --[[@as string]],
        "roslyn",
        "Microsoft.CodeAnalysis.LanguageServer.dll"
    ),
    -- NOTE: Set `filewatching` to false if you experience performance problems.
    -- Defaults to true, since turning it off is a hack.
    -- If you notice that the server is _super_ slow, it is probably because of file watching
    -- I noticed that neovim became super unresponsive on some large codebases, and that was because
    -- it schedules the file watching on the event loop.
    -- This issue went away by disabling that capability. However, roslyn will fallback to its own
    -- file watching, which can make the server super slow to initialize.
    -- Setting this option to false will indicate to the server that neovim will do the file watching.
    -- However, in `hacks.lua` I will also just don't start off any watchers, which seems to make the server
    -- a lot faster to initialize.
    filewatching = true,
})

1. The plugin will look for a .sln file in the parent directories of cwd, until it finds one.
2. If only one .sln file is found, it will be used to start the server. If multiple .slns are found, you have to run CSTarget to choose the proper solution file.
3. You should see two notifications, if everything goes well. The first one will say Roslyn client initialized for target <target>. It means the server is running and it has started to index your sln. The second one will say Roslyn project initialization complete. It means that the server has finished indexing of your sln.
4. The LSP features (like Go To Definition) will be available only after the mentioned notifications get shown.

• Roslyn requires that .csproj projects are referenced by the matched .sln it discovers. Otherwise, it won't discover and load suggestions for .cs files under the .csproj. Make sure you add your projects to the .sln (dotnet sln add <path-to-csproj>) or Roslyn won't load up properly!

Please note that some features from the VS Code extension might not be supported by this plugin.