transitioned from nvim-lsp-installer to mason and mason-lspconfig.

neovim/.config/nvim/lua/LSPconfig.lua

@@ -1,5 +1,3 @@
-local lsp_installer = require("nvim-lsp-installer")
-
 local opts = {}
 
 local on_attach = function()
@@ -30,4 +28,25 @@ local on_attach = function()
 	set_keymap('', ';lp', '<cmd>lua vim.diagnostic.goto_next()<CR>', opts)
 	set_keymap('', ';lm', '<cmd>lua vim.lsp.buf.formatting()<CR>', opts)
 end
-on_attach()
+require("mason-lspconfig").setup_handlers({
+	function(server_name)
+		require("lspconfig")[server_name].setup{}
+		on_attach()
+	end,
+	["rust_analyzer"] = function()
+		require('rust-tools-setup')
+		on_attach()
+	end,
+	["sumneko_lua"] = function ()
+		require('lspconfig').sumneko_lua.setup {
+			settings = {
+				Lua = {
+					diagnostics = {
+						globals = { "vim" }
+					}
+				}
+			}
+		}
+		on_attach()
+	end,
+})

neovim/.config/nvim/lua/packages.lua

@@ -26,33 +26,44 @@ return require('packer').startup(function(use)
 	}
 	use {
 		{
-			"williamboman/nvim-lsp-installer",
-			config = function ()
-				require("nvim-lsp-installer").setup {
-					ensure_installed = {
-						'pyright',
-						'bashls',
-						'rust_analyzer',
-						'sumneko_lua',
-						'texlab',
-					},
-					automatic_installation = false,
+			"williamboman/mason.nvim",
+			config = function()
+				require("mason").setup({
 					ui = {
 						icons = {
-							server_installed = "✓",
-							server_pending = "➜",
-							server_uninstalled = "✗"
-						}
+							package_installed = "✓",
+							package_pending = "➜",
+							package_uninstalled = "✗"
 						}
 					}
+				})
+			end
+		},
+		{
+		    "williamboman/mason-lspconfig.nvim",
+			after = "mason.nvim",
+			config = function()
+				require("mason-lspconfig").setup({
+					ensure_installed = {
+						"sumneko_lua",
+						"rust_analyzer",
+						'pyright',
+						'bashls',
+						'texlab'
+					},
+					automatic_installation=true
+				})
 			end
 		},
 		{
 			"neovim/nvim-lspconfig",
-			after = "nvim-lsp-installer",
+			after = "mason-lspconfig.nvim",
 			config = function()
 				require('LSPconfig')
 			end
+		},
+		{'simrat39/rust-tools.nvim',
+			after = "nvim-lspconfig",
 		}
 	}
 
@@ -289,11 +300,6 @@ return require('packer').startup(function(use)
 
 	--language specific tools.
 
-	use{'simrat39/rust-tools.nvim',
-		config=function()
-			require('rust-tools-setup')
-		end
-	}
 
 	if Packer_Bootstrap then
 		require('packer').sync()

neovim/.config/nvim/lua/rust-tools-setup.lua

@@ -2,7 +2,7 @@ local nvim_lsp = require'lspconfig'
 local opts = {
 	tools = {
 	autoSetHints = true,
-	hover_with_actions = true,
+	RustHoverActions = true,
 
 	-- how to execute terminal commands
 	executor = require("rust-tools/executors").termopen,