diff --git a/src/nvim/testdir/test_expr.vim b/src/nvim/testdir/test_expr.vim
index 9dbc923b96..f33358c59a 100644
--- a/src/nvim/testdir/test_expr.vim
+++ b/src/nvim/testdir/test_expr.vim
@@ -92,10 +92,11 @@ func Test_getreg_empty_list()
   let y = x
   call add(x, 'foo')
   call assert_equal(['foo'], y)
+  call assert_fails('call getreg([])', 'E730:')
 endfunc
 
 func Test_loop_over_null_list()
-  let null_list = submatch(1, 1)
+  let null_list = v:_null_list
   for i in null_list
     call assert_report('should not get here')
   endfor
diff --git a/src/nvim/testdir/test_functions.vim b/src/nvim/testdir/test_functions.vim
index f0cd8ee878..1308beeae5 100644
--- a/src/nvim/testdir/test_functions.vim
+++ b/src/nvim/testdir/test_functions.vim
@@ -127,6 +127,7 @@ func Test_min()
 
   call assert_fails('call min(1)', 'E712:')
   " call assert_fails('call min(v:none)', 'E712:')
+  call assert_fails('call min([1, {}])', 'E728:')
 
   " check we only get one error
   call assert_fails('call min([[1], #{}])', ['E745:', 'E745:'])
@@ -591,6 +592,7 @@ func Test_tr()
   call assert_fails("let s=tr('abcd', 'abcd', 'def')", 'E475:')
   call assert_equal('hEllO', tr('hello', 'eo', 'EO'))
   call assert_equal('hello', tr('hello', 'xy', 'ab'))
+  call assert_fails('call tr("abc", "123", "₁₂")', 'E475:')
   set encoding=utf8
 endfunc
 
diff --git a/src/nvim/testdir/test_listdict.vim b/src/nvim/testdir/test_listdict.vim
index 7ea488f41d..8d7bede403 100644
--- a/src/nvim/testdir/test_listdict.vim
+++ b/src/nvim/testdir/test_listdict.vim
@@ -516,6 +516,11 @@ func Test_list_locked_var_unlet()
       call assert_equal(expected[depth][u][1], ps)
     endfor
   endfor
+  " Deleting a list range should fail if the range is locked
+  let l = [1, 2, 3, 4]
+  lockvar l[1:2]
+  call assert_fails('unlet l[1:2]', 'E741:')
+  unlet l
 endfunc
 
 " Locked variables and :unlet or list / dict functions
diff --git a/src/nvim/testdir/test_registers.vim b/src/nvim/testdir/test_registers.vim
index 5bdbbe7a22..a308a3e7eb 100644
--- a/src/nvim/testdir/test_registers.vim
+++ b/src/nvim/testdir/test_registers.vim
@@ -299,6 +299,7 @@ endfunc
 
 func Test_set_register()
   call assert_fails("call setreg('#', 200)", 'E86:')
+  " call assert_fails("call setreg('a', test_unknown())", 'E908:')
 
   edit Xfile_alt_1
   let b1 = bufnr('')
@@ -490,6 +491,14 @@ func Test_get_reginfo()
   let info = getreginfo('"')
   call assert_equal('z', info.points_to)
 
+  let @a="a1b2"
+  nnoremap <F2> <Cmd>let g:RegInfo = getreginfo()<CR>
+  exe "normal \"a\<F2>"
+  call assert_equal({'regcontents': ['a1b2'], 'isunnamed': v:false,
+        \ 'regtype': 'v'}, g:RegInfo)
+  nunmap <F2>
+  unlet g:RegInfo
+
   bwipe!
 endfunc
 
diff --git a/src/nvim/testdir/test_user_func.vim b/src/nvim/testdir/test_user_func.vim
index f13c082814..4742293ed5 100644
--- a/src/nvim/testdir/test_user_func.vim
+++ b/src/nvim/testdir/test_user_func.vim
@@ -163,6 +163,16 @@ func Test_default_arg()
 	\ .. "1    return deepcopy(a:)\n"
 	\ .. "   endfunction",
 	\ execute('func Args2'))
+
+  " Error in default argument expression
+  let l =<< trim END
+    func F1(x = y)
+      return a:x * 2
+    endfunc
+    echo F1()
+  END
+  let @a = l->join("\n")
+  call assert_fails("exe @a", 'E121:')
 endfunc
 
 func s:addFoo(lead)