diff --git a/runtime/lua/vim/diagnostic.lua b/runtime/lua/vim/diagnostic.lua
index 299f34c921..4fb8c6a686 100644
--- a/runtime/lua/vim/diagnostic.lua
+++ b/runtime/lua/vim/diagnostic.lua
@@ -282,6 +282,11 @@ M.severity = {
   [2] = 'WARN',
   [3] = 'INFO',
   [4] = 'HINT',
+  --- Mappings from qflist/loclist error types to severities
+  E = 1,
+  W = 2,
+  I = 3,
+  N = 4,
 }
 
 --- @alias vim.diagnostic.SeverityInt 1|2|3|4
@@ -289,12 +294,6 @@ M.severity = {
 --- See |diagnostic-severity| and |vim.diagnostic.get()|
 --- @alias vim.diagnostic.SeverityFilter vim.diagnostic.Severity|vim.diagnostic.Severity[]|{min:vim.diagnostic.Severity,max:vim.diagnostic.Severity}
 
--- Mappings from qflist/loclist error types to severities
-M.severity.E = M.severity.ERROR
-M.severity.W = M.severity.WARN
-M.severity.I = M.severity.INFO
-M.severity.N = M.severity.HINT
-
 --- @type vim.diagnostic.Opts
 local global_diagnostic_options = {
   signs = true,
@@ -891,14 +890,14 @@ local function next_diagnostic(search_forward, opts)
   if opts.win_id then
     vim.deprecate('opts.win_id', 'opts.winid', '0.13')
     opts.winid = opts.win_id
-    opts.win_id = nil
+    opts.win_id = nil --- @diagnostic disable-line
   end
 
   -- Support deprecated cursor_position alias
   if opts.cursor_position then
     vim.deprecate('opts.cursor_position', 'opts.pos', '0.13')
     opts.pos = opts.cursor_position
-    opts.cursor_position = nil
+    opts.cursor_position = nil --- @diagnostic disable-line
   end
 
   local winid = opts.winid or api.nvim_get_current_win()
@@ -979,7 +978,7 @@ local function goto_diagnostic(diagnostic, opts)
   if opts.win_id then
     vim.deprecate('opts.win_id', 'opts.winid', '0.13')
     opts.winid = opts.win_id
-    opts.win_id = nil
+    opts.win_id = nil --- @diagnostic disable-line
   end
 
   local winid = opts.winid or api.nvim_get_current_win()
@@ -992,8 +991,9 @@ local function goto_diagnostic(diagnostic, opts)
     vim.cmd('normal! zv')
   end)
 
-  if opts.float then
-    local float_opts = type(opts.float) == 'table' and opts.float or {}
+  local float_opts = opts.float
+  if float_opts then
+    float_opts = type(float_opts) == 'table' and float_opts or {}
     vim.schedule(function()
       M.open_float(vim.tbl_extend('keep', float_opts, {
         bufnr = api.nvim_win_get_buf(winid),
@@ -1317,7 +1317,7 @@ function M.jump(opts)
   if opts.cursor_position then
     vim.deprecate('opts.cursor_position', 'opts.pos', '0.13')
     opts.pos = opts.cursor_position
-    opts.cursor_position = nil
+    opts.cursor_position = nil --- @diagnostic disable-line
   end
 
   local diag = nil
@@ -1488,14 +1488,9 @@ M.handlers.underline = {
     local get_priority = severity_to_extmark_priority(vim.hl.priorities.diagnostics, opts)
 
     for _, diagnostic in ipairs(diagnostics) do
-      --- @type string?
+      -- Default to error if we don't have a highlight associated
       local higroup = underline_highlight_map[assert(diagnostic.severity)]
-
-      if higroup == nil then
-        -- Default to error if we don't have a highlight associated
-        -- TODO(lewis6991): this is always nil since underline_highlight_map only has integer keys
-        higroup = underline_highlight_map.Error
-      end
+        or underline_highlight_map[vim.diagnostic.severity.ERROR]
 
       if diagnostic._tags then
         -- TODO(lewis6991): we should be able to stack these.
@@ -2115,9 +2110,10 @@ function M.enable(enable, filter)
 
   enable = enable == nil and true or enable
   local bufnr = filter.bufnr
+  local ns_id = filter.ns_id
 
-  if bufnr == nil then
-    if filter.ns_id == nil then
+  if not bufnr then
+    if not ns_id then
       diagnostic_disabled = (
         enable
           -- Enable everything by setting diagnostic_disabled to an empty table.
@@ -2131,12 +2127,12 @@ function M.enable(enable, filter)
         })
       )
     else
-      local ns = M.get_namespace(filter.ns_id)
+      local ns = M.get_namespace(ns_id)
       ns.disabled = not enable
     end
   else
     bufnr = get_bufnr(bufnr)
-    if filter.ns_id == nil then
+    if not ns_id then
       diagnostic_disabled[bufnr] = (not enable) and true or nil
     else
       if type(diagnostic_disabled[bufnr]) ~= 'table' then
@@ -2146,14 +2142,14 @@ function M.enable(enable, filter)
           diagnostic_disabled[bufnr] = {}
         end
       end
-      diagnostic_disabled[bufnr][filter.ns_id] = (not enable) and true or nil
+      diagnostic_disabled[bufnr][ns_id] = (not enable) and true or nil
     end
   end
 
   if enable then
-    M.show(filter.ns_id, bufnr)
+    M.show(ns_id, bufnr)
   else
-    M.hide(filter.ns_id, bufnr)
+    M.hide(ns_id, bufnr)
   end
 end
 
diff --git a/runtime/lua/vim/filetype/detect.lua b/runtime/lua/vim/filetype/detect.lua
index 1cc81b177f..1b9e28efad 100644
--- a/runtime/lua/vim/filetype/detect.lua
+++ b/runtime/lua/vim/filetype/detect.lua
@@ -1908,7 +1908,7 @@ local function match_from_hashbang(contents, path, dispatch_extension)
   end
 
   for k, v in pairs(patterns_hashbang) do
-    local ft = type(v) == 'table' and v[1] or v
+    local ft = type(v) == 'table' and v[1] or v --[[@as string]]
     local opts = type(v) == 'table' and v[2] or {}
     if opts.vim_regex and matchregex(name, k) or name:find(k) then
       return ft
@@ -2080,6 +2080,7 @@ local function match_from_text(contents, path)
         return ft
       end
     else
+      --- @cast k string
       local opts = type(v) == 'table' and v[2] or {}
       if opts.start_lnum and opts.end_lnum then
         assert(
diff --git a/runtime/lua/vim/glob.lua b/runtime/lua/vim/glob.lua
index 22073b15c8..4f86d5e1ca 100644
--- a/runtime/lua/vim/glob.lua
+++ b/runtime/lua/vim/glob.lua
@@ -48,7 +48,7 @@ function M.to_lpeg(pattern)
   end
 
   -- luacheck: push ignore s
-  local function cut(s, idx, match)
+  local function cut(_s, idx, match)
     return idx, match
   end
   -- luacheck: pop
diff --git a/runtime/lua/vim/shared.lua b/runtime/lua/vim/shared.lua
index 94a194cde9..1a3b33c885 100644
--- a/runtime/lua/vim/shared.lua
+++ b/runtime/lua/vim/shared.lua
@@ -782,7 +782,8 @@ end
 
 do
   --- @alias vim.validate.Validator
-  --- | type|'callable'
+  --- | type
+  --- | 'callable'
   --- | (type|'callable')[]
   --- | fun(v:any):boolean, string?
 
@@ -1170,11 +1171,13 @@ function vim._defer_deprecated_module(old_name, new_name)
     ---@param k string
     __index = function(_, k)
       vim.deprecate(old_name, new_name, '2.0.0', nil, false)
+      --- @diagnostic disable-next-line:no-unknown
       local target = require(new_name)
       return target[k]
     end,
     __call = function(self)
       vim.deprecate(old_name, new_name, '2.0.0', nil, false)
+      --- @diagnostic disable-next-line:no-unknown
       local target = require(new_name)
       return target(self)
     end,
@@ -1217,11 +1220,14 @@ local state_restore_order = { 'bo', 'wo', 'go', 'env' }
 --- @param context vim.context.mods
 --- @return vim.context.state
 local get_context_state = function(context)
+  --- @type vim.context.state
   local res = { bo = {}, env = {}, go = {}, wo = {} }
 
   -- Use specific order from possibly most to least intrusive
   for _, scope in ipairs(scope_order) do
-    for name, _ in pairs(context[scope] or {}) do
+    for name, _ in
+      pairs(context[scope] or {} --[[@as table<string,any>]])
+    do
       local sc = scope == 'o' and scope_map[vim.api.nvim_get_option_info2(name, {}).scope] or scope
 
       -- Do not override already set state and fall back to `vim.NIL` for
@@ -1315,7 +1321,10 @@ function vim._with(context, f)
     -- Apply some parts of the context in specific order
     -- NOTE: triggers `OptionSet` event
     for _, scope in ipairs(scope_order) do
-      for name, context_value in pairs(context[scope] or {}) do
+      for name, context_value in
+        pairs(context[scope] or {} --[[@as table<string,any>]])
+      do
+        --- @diagnostic disable-next-line:no-unknown
         vim[scope][name] = context_value
       end
     end
@@ -1326,7 +1335,10 @@ function vim._with(context, f)
     -- Restore relevant cached values in specific order, global scope last
     -- NOTE: triggers `OptionSet` event
     for _, scope in ipairs(state_restore_order) do
-      for name, cached_value in pairs(state[scope]) do
+      for name, cached_value in
+        pairs(state[scope] --[[@as table<string,any>]])
+      do
+        --- @diagnostic disable-next-line:no-unknown
         vim[scope][name] = cached_value
       end
     end
diff --git a/runtime/lua/vim/termcap.lua b/runtime/lua/vim/termcap.lua
index 2c36561587..4aa41bba9b 100644
--- a/runtime/lua/vim/termcap.lua
+++ b/runtime/lua/vim/termcap.lua
@@ -38,7 +38,7 @@ function M.query(caps, cb)
       local k, rest = resp:match('^\027P1%+r(%x+)(.*)$')
       if k and rest then
         local cap = vim.text.hexdecode(k)
-        if not pending[cap] then
+        if not cap or not pending[cap] then
           -- Received a response for a capability we didn't request. This can happen if there are
           -- multiple concurrent XTGETTCAP requests
           return
diff --git a/runtime/lua/vim/treesitter.lua b/runtime/lua/vim/treesitter.lua
index 9f6dc53932..dca89f413c 100644
--- a/runtime/lua/vim/treesitter.lua
+++ b/runtime/lua/vim/treesitter.lua
@@ -165,7 +165,7 @@ function M.get_node_range(node_or_range)
   if type(node_or_range) == 'table' then
     return unpack(node_or_range)
   else
-    return node_or_range:range()
+    return node_or_range:range(false)
   end
 end
 
diff --git a/runtime/lua/vim/ui.lua b/runtime/lua/vim/ui.lua
index 899709d3cf..cd159f0172 100644
--- a/runtime/lua/vim/ui.lua
+++ b/runtime/lua/vim/ui.lua
@@ -43,7 +43,9 @@ function M.select(items, opts, on_choice)
   opts = opts or {}
   local choices = { opts.prompt or 'Select one of:' }
   local format_item = opts.format_item or tostring
-  for i, item in ipairs(items) do
+  for i, item in
+    ipairs(items --[[@as any[] ]])
+  do
     table.insert(choices, string.format('%d: %s', i, format_item(item)))
   end
   local choice = vim.fn.inputlist(choices)
@@ -204,7 +206,9 @@ function M._get_urls()
             if vim.treesitter.node_contains(node, range) then
               local url = metadata[id] and metadata[id].url
               if url and match[url] then
-                for _, n in ipairs(match[url]) do
+                for _, n in
+                  ipairs(match[url] --[[@as TSNode[] ]])
+                do
                   urls[#urls + 1] =
                     vim.treesitter.get_node_text(n, bufnr, { metadata = metadata[url] })
                 end