diff --git a/doc/lspconfig.txt b/doc/lspconfig.txt
index 5a1da207e7..6d30a27e17 100644
--- a/doc/lspconfig.txt
+++ b/doc/lspconfig.txt
@@ -110,7 +110,7 @@ listed in `:help vim.lsp.start_client()` with the following unique entries:
 
 - {on_new_config}
 
-    `function(new_config, new_root_dir)`
+    `function(new_config, new_root_dir, single_file)`
 
     Function executed after a root directory is detected. This is used to
     modify the server configuration (including `cmd` itself). Most commonly,
diff --git a/lua/lspconfig/configs.lua b/lua/lspconfig/configs.lua
index 532befd10c..e49e75fffa 100644
--- a/lua/lspconfig/configs.lua
+++ b/lua/lspconfig/configs.lua
@@ -186,7 +186,7 @@ function configs.__newindex(t, config_name, config_def)
       M.manager = nil
     end
 
-    local make_config = function(root_dir)
+    local make_config = function(root_dir, single_file)
       local new_config = tbl_deep_extend('keep', vim.empty_dict(), config) --[[@as lspconfig.Config]]
       new_config.capabilities = tbl_deep_extend('keep', new_config.capabilities, {
         workspace = {
@@ -195,10 +195,10 @@ function configs.__newindex(t, config_name, config_def)
       })
 
       if config_def.on_new_config then
-        pcall(config_def.on_new_config, new_config, root_dir)
+        pcall(config_def.on_new_config, new_config, root_dir, single_file)
       end
       if config.on_new_config then
-        pcall(config.on_new_config, new_config, root_dir)
+        pcall(config.on_new_config, new_config, root_dir, single_file)
       end
 
       new_config.on_init = util.add_hook_after(new_config.on_init, function(client, result)
diff --git a/lua/lspconfig/manager.lua b/lua/lspconfig/manager.lua
index 5d260b414e..0beefdcf64 100644
--- a/lua/lspconfig/manager.lua
+++ b/lua/lspconfig/manager.lua
@@ -25,11 +25,11 @@ end
 --- @class lspconfig.Manager
 --- @field _clients table<string,table>
 --- @field config lspconfig.Config
---- @field make_config fun(root_dir: string): lspconfig.Config
+--- @field make_config fun(root_dir: string, single_file: boolean): lspconfig.Config
 local M = {}
 
 --- @param config lspconfig.Config
---- @param make_config fun(root_dir: string): lspconfig.Config
+--- @param make_config fun(root_dir: string, single_file: boolean): lspconfig.Config
 --- @return lspconfig.Manager
 function M.new(config, make_config)
   return setmetatable({
@@ -200,7 +200,7 @@ end
 ---@param bufnr integer
 function M:add(root_dir, single_file, bufnr)
   root_dir = util.path.sanitize(root_dir)
-  local new_config = self.make_config(root_dir)
+  local new_config = self.make_config(root_dir, single_file)
   local client = self:_get_client_from_cache(root_dir, new_config.name)
 
   if not client then
diff --git a/lua/lspconfig/server_configurations/rust_analyzer.lua b/lua/lspconfig/server_configurations/rust_analyzer.lua
index 6ed471d2d5..e73d25fe4b 100644
--- a/lua/lspconfig/server_configurations/rust_analyzer.lua
+++ b/lua/lspconfig/server_configurations/rust_analyzer.lua
@@ -70,7 +70,13 @@ return {
         or util.root_pattern 'rust-project.json'(fname)
         or util.find_git_ancestor(fname)
     end,
+    single_file_support = true,
     capabilities = register_cap(),
+    on_new_config = function(config, _, single_file)
+      if single_file then
+        config.init_options.detachedFiles = { vim.api.nvim_buf_get_name(0) }
+      end
+    end,
   },
   commands = {
     CargoReload = {