feat(lsp): add native inlay hints (neovim v0.10 only)

lua/astronvim/options.lua

@@ -59,6 +59,7 @@ local options = astronvim.user_opts("options", {
     diagnostics_mode = 3, -- set the visibility of diagnostics in the UI (0=off, 1=only show in status line, 2=virtual text off, 3=all on)
     highlighturl_enabled = true, -- highlight URLs by default
     icons_enabled = true, -- disable icons in the UI (disable if no nerd font is available)
+    inlay_hints_enabled = false, -- enable or disable LSP inlay hints on startup (Neovim v0.10 only)
     lsp_handlers_enabled = true, -- enable or disable default vim.lsp.handlers (hover and signatureHelp)
     semantic_tokens_enabled = true, -- enable or disable LSP semantic tokens on startup
     ui_notifications_enabled = true, -- disable notifications (TODO: rename to  notifications_enabled in AstroNvim v4)

lua/astronvim/utils/lsp.lua

@@ -289,6 +289,18 @@ M.on_attach = function(client, bufnr)
     }
   end
 
+  if client.supports_method "textDocument/inlayHint" then
+    if vim.b.inlay_hints_enabled == nil then vim.b.inlay_hints_enabled = vim.g.inlay_hints_enabled end
+    -- TODO: remove check after dropping support for Neovim v0.9
+    if vim.lsp.buf.inlay_hint then
+      if vim.b.inlay_hints_enabled then vim.lsp.buf.inlay_hint(bufnr, true) end
+      lsp_mappings.n["<leader>uH"] = {
+        function() require("astronvim.utils.ui").toggle_buffer_inlay_hints(bufnr) end,
+        desc = "Toggle LSP inlay hints (buffer)",
+      }
+    end
+  end
+
   if client.supports_method "textDocument/references" then
     lsp_mappings.n["gr"] = {
       function() vim.lsp.buf.references() end,

lua/astronvim/utils/ui.lua

@@ -91,6 +91,17 @@ function M.toggle_buffer_semantic_tokens(bufnr)
   end
 end
 
+--- Toggle buffer LSP inlay hints
+---@param bufnr? number the buffer to toggle the clients on
+function M.toggle_buffer_inlay_hints(bufnr)
+  vim.b.inlay_hints_enabled = not vim.b.inlay_hints_enabled
+  -- TODO: remove check after dropping support for Neovim v0.9
+  if vim.lsp.buf.inlay_hint then
+    vim.lsp.buf.inlay_hint(bufnr or 0, vim.b.inlay_hints_enabled)
+    notify(string.format("Inlay hints %s", bool2str(vim.b.inlay_hints_enabled)))
+  end
+end
+
 --- Toggle codelens
 function M.toggle_codelens()
   vim.g.codelens_enabled = not vim.g.codelens_enabled