Neovim

gsa-lsp speaks standard LSP using textDocument/inlayHint, textDocument/hover, textDocument/publishDiagnostics, and textDocument/codeAction. Neovim's built-in LSP client handles all of these natively.

How It Works

gsa-lsp runs alongside gopls — gopls handles navigation/completion, gsa-lsp provides struct layout analysis via inlay hints, hover, and diagnostics.

Feature	LSP method	What it shows
Struct size at definition	textDocument/inlayHint	Total struct size (and optimizable size if applicable)
Field offset/size/padding	textDocument/inlayHint	Per-field offset, byte size, and preceding padding
Full layout breakdown	textDocument/hover	Field-by-field memory layout with optimal layout alternative
Optimization warnings	textDocument/publishDiagnostics	Warnings when layout can be optimized or GC scan range reduced
Quick fix	textDocument/codeAction	"Reorder struct fields" code action on warning diagnostics

No plugins needed — Neovim's built-in LSP client supports all required methods.

Installation

1. Install gsa-lsp binary

curl -fsSL https://padiazg.github.io/go-struct-analyzer/install.sh | sh

Or download a pre-built binary from GitHub Releases.

2. Configure Neovim LSP

Add to your Neovim config (e.g. ~/.config/nvim/init.lua):

vim.lsp.config('gsa_lsp', {
  cmd = { 'gsa-lsp', 'lsp' },
  filetypes = { 'go' },
  init_options = {
    architecture = 'amd64',
    gcPressureSeverityWarning = false,
    enableStructOptimizationWarnings = true,
    enableReorderCodeAction = true,
    enableGCPressureWarnings = true,
  },
})

vim.lsp.enable('gsa_lsp')

gsa-lsp starts alongside gopls when you open a Go file. Neovim displays inlay hints, hover information, diagnostics, and code actions automatically.

Avoid duplicate registration. Registering gsa-lsp through both an autocmd + vim.lsp.start and vim.lsp.config/vim.lsp.enable (or with two different client names) spins up two independent server processes. Neovim then renders one hover block per client, producing duplicated content. Use exactly one registration method.

Using with gopls

If you already have gopls configured, gsa-lsp works as a secondary server — both run concurrently. gopls provides navigation, completion, and refactoring while gsa-lsp provides struct layout analysis.

LazyVim

LazyVim's nvim-lspconfig spec loops over an opts.servers table and calls vim.lsp.config/vim.lsp.enable for you. In your LazyVim config:

return {
  opts = {
    servers = {
      gsa_lsp = {
        cmd = { 'gsa-lsp', 'lsp' },
        init_options = {
          architecture = 'amd64',
          gcPressureSeverityWarning = false,
          enableStructOptimizationWarnings = true,
          enableReorderCodeAction = true,
          enableGCPressureWarnings = true,
        },
      },
    },
  },
}

Changing settings without restarting (advanced)

gsa-lsp applies configuration changes live via workspace/didChangeConfiguration — no server restart needed. Push new settings from a keymap or autocmd:

vim.keymap.set('n', '<leader>gsr', function()
  local clients = vim.lsp.get_clients({ name = 'gsa_lsp' })
  for _, client in ipairs(clients) do
    client:notify('workspace/didChangeConfiguration', {
      settings = { goStructAnalyzer = { enableReorderCodeAction = false } },
    })
  end
end, { desc = 'Disable gsa-lsp reorder quick fix' })

Verifying

Open a Go file with struct types. You should see:

• Inlay hints showing struct total size after type Foo struct and field offset/size on each field
• Hover over a struct name (K by default) for full memory layout
• Diagnostics in the location list for optimizable structs

Troubleshooting

• Inlay hints not showing: Neovim 0.10+ required. Inlay hints are opt-in — enable them in your LSP attach handler or init.lua:

vim.api.nvim_create_autocmd('LspAttach', {
  callback = function(args)
    vim.lsp.inlay_hint.enable(true, { bufnr = args.buf })
  end,
})

Or toggle per-buffer with :LspInlayHint. Run :checkhealth vim.lsp to verify LSP client state.

• Hover shows nothing: K (default) triggers vim.lsp.buf.hover() — verify the keymap isn't shadowed by another plugin (:map K). gsa-lsp returns a full memory layout table on any struct definition line.

• Server not starting: verify gsa-lsp is on your $PATH and executable. Check :LspLog for errors.

• Hover shows duplicated content: two separate LSP clients are running. This happens when gsa-lsp is registered twice — e.g. one registration via FileType autocmd + vim.lsp.start and another via vim.lsp.config/vim.lsp.enable, or using two different client names. Remove the duplicate registration; Neovim should show exactly one hover block per struct.