diff --git a/src/channel.c b/src/channel.c
index 5f78777..46bdc0e 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -4890,9 +4890,15 @@
     void
 f_ch_log(typval_T *argvars, typval_T *rettv UNUSED)
 {
-    char_u	*msg = tv_get_string(&argvars[0]);
+    char_u	*msg;
     channel_T	*channel = NULL;
 
+    if (in_vim9script()
+	    && (check_for_string_arg(argvars, 0) == FAIL
+		|| check_for_opt_chan_or_job_arg(argvars, 1) == FAIL))
+	return;
+
+    msg = tv_get_string(&argvars[0]);
     if (argvars[1].v_type != VAR_UNKNOWN)
 	channel = get_channel_arg(&argvars[1], FALSE, FALSE, 0);
 
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 2a4e1b2..22952d4 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -542,7 +542,8 @@
 }
 
 /*
- * Check "type" which is the third argument of extend().
+ * Check "type" which is the third argument of extend() (number or string or
+ * any)
  */
     static int
 arg_extend3(type_T *type, argcontext_T *context)
@@ -557,7 +558,8 @@
 }
 
 /*
- * Check "type" which is the second argument of remove().
+ * Check "type" which is the second argument of remove() (number or string or
+ * any)
  */
     static int
 arg_remove2(type_T *type, argcontext_T *context)
@@ -572,7 +574,8 @@
 }
 
 /*
- * Check "type" which is the first argument of repeat().
+ * Check "type" which is the first argument of repeat() (string or number or
+ * list or any)
  */
     static int
 arg_repeat1(type_T *type, argcontext_T *context)
@@ -588,7 +591,8 @@
 }
 
 /*
- * Check "type" which is the first argument of slice().
+ * Check "type" which is the first argument of slice() (list or blob or string
+ * or any)
  */
     static int
 arg_slice1(type_T *type, argcontext_T *context)
@@ -604,7 +608,8 @@
 }
 
 /*
- * Check "type" which is the first argument of count().
+ * Check "type" which is the first argument of count() (string or list or dict
+ * or any)
  */
     static int
 arg_count1(type_T *type, argcontext_T *context)
@@ -620,7 +625,8 @@
 }
 
 /*
- * Check "type" which is the first argument of cursor().
+ * Check "type" which is the first argument of cursor() (number or string or
+ * list or any)
  */
     static int
 arg_cursor1(type_T *type, argcontext_T *context)
@@ -666,6 +672,7 @@
 static argcheck_T arg2_string_bool[] = {arg_string, arg_bool};
 static argcheck_T arg2_string_or_list_dict[] = {arg_string_or_list_any, arg_dict_any};
 static argcheck_T arg2_string_string_or_number[] = {arg_string, arg_string_or_nr};
+static argcheck_T arg2_string_chan_or_job[] = {arg_string, arg_chan_or_job};
 static argcheck_T arg2_list_number[] = {arg_list_number, arg_list_number};
 static argcheck_T arg2_list_number_bool[] = {arg_list_number, arg_bool};
 static argcheck_T arg2_list_any_string[] = {arg_list_any, arg_string};
@@ -690,11 +697,14 @@
 static argcheck_T arg2_buffer_bool[] = {arg_buffer, arg_bool};
 static argcheck_T arg2_buffer_lnum[] = {arg_buffer, arg_lnum};
 static argcheck_T arg2_buffer_list_any[] = {arg_buffer, arg_list_any};
+static argcheck_T arg2_buffer_any[] = {arg_buffer, NULL};
 static argcheck_T arg3_string[] = {arg_string, arg_string, arg_string};
 static argcheck_T arg3_number[] = {arg_number, arg_number, arg_number};
 static argcheck_T arg3_number_number_dict[] = {arg_number, arg_number, arg_dict_any};
+static argcheck_T arg3_number_string_string[] = {arg_number, arg_string, arg_string};
 static argcheck_T arg3_number_string_any[] = {arg_number, arg_string, NULL};
 static argcheck_T arg3_number_string_buffer[] = {arg_number, arg_string, arg_buffer};
+static argcheck_T arg3_number_any_dict[] = {arg_number, NULL, arg_dict_any};
 static argcheck_T arg3_string_nr_bool[] = {arg_string, arg_number, arg_bool};
 static argcheck_T arg3_string_string_nr[] = {arg_string, arg_string, arg_number};
 static argcheck_T arg3_string_string_dict[] = {arg_string, arg_string, arg_dict_any};
@@ -707,6 +717,7 @@
 static argcheck_T arg3_buffer_lnum_lnum[] = {arg_buffer, arg_lnum, arg_lnum};
 static argcheck_T arg3_buffer_number_number[] = {arg_buffer, arg_number, arg_number};
 static argcheck_T arg3_buffer_string_dict[] = {arg_buffer, arg_string, arg_dict_any};
+static argcheck_T arg3_buffer_string_any[] = {arg_buffer, arg_string, NULL};
 static argcheck_T arg4_number_number_string_any[] = {arg_number, arg_number, arg_string, NULL};
 static argcheck_T arg4_string_string_number_string[] = {arg_string, arg_string, arg_number, arg_string};
 static argcheck_T arg5_number[] = {arg_number, arg_number, arg_number, arg_number, arg_number};
@@ -726,12 +737,13 @@
 static argcheck_T arg2_mapfilter[] = {arg_list_or_dict_or_blob, NULL};
 static argcheck_T arg14_maparg[] = {arg_string, arg_string, arg_bool, arg_bool};
 static argcheck_T arg25_matchadd[] = {arg_string, arg_string, arg_number, arg_number, arg_dict_any};
-static argcheck_T arg25_matchaddpos[] = {arg_string, arg_list_number, arg_number, arg_number, arg_dict_any};
+static argcheck_T arg25_matchaddpos[] = {arg_string, arg_list_any, arg_number, arg_number, arg_dict_any};
 static argcheck_T arg23_reduce[] = {arg_list_or_blob, NULL, NULL};
 static argcheck_T arg24_remote_expr[] = {arg_string, arg_string, arg_string, arg_number};
 static argcheck_T arg23_remove[] = {arg_list_or_dict_or_blob, arg_remove2, arg_number};
 static argcheck_T arg2_repeat[] = {arg_repeat1, arg_number};
 static argcheck_T arg15_search[] = {arg_string, arg_string, arg_number, arg_number, NULL};
+static argcheck_T arg37_searchpair[] = {arg_string, arg_string, arg_string, arg_string, NULL, arg_number, arg_number};
 static argcheck_T arg3_setbufline[] = {arg_buffer, arg_lnum, arg_str_or_nr_or_list};
 static argcheck_T arg2_setline[] = {arg_lnum, NULL};
 static argcheck_T arg24_setloclist[] = {arg_number, arg_list_any, arg_string, arg_dict_any};
@@ -1146,7 +1158,7 @@
 			ret_job,	    JOB_FUNC(f_ch_getjob)},
     {"ch_info",		1, 1, FEARG_1,	    arg1_chan_or_job,
 			ret_dict_any,	    JOB_FUNC(f_ch_info)},
-    {"ch_log",		1, 2, FEARG_1,	    NULL,
+    {"ch_log",		1, 2, FEARG_1,	    arg2_string_chan_or_job,
 			ret_void,	    JOB_FUNC(f_ch_log)},
     {"ch_logfile",	1, 2, FEARG_1,	    arg2_string,
 			ret_void,	    JOB_FUNC(f_ch_logfile)},
@@ -1202,7 +1214,7 @@
 			ret_float,	    FLOAT_FUNC(f_cosh)},
     {"count",		2, 4, FEARG_1,	    arg24_count,
 			ret_number,	    f_count},
-    {"cscope_connection",0,3, 0,	    NULL,
+    {"cscope_connection",0,3, 0,	    arg3_number_string_string,
 			ret_number,	    f_cscope_connection},
     {"cursor",		1, 3, FEARG_1,	    arg13_cursor,
 			ret_number,	    f_cursor},
@@ -1310,7 +1322,7 @@
 			ret_list_dict_any,  f_getbufinfo},
     {"getbufline",	2, 3, FEARG_1,	    arg3_buffer_lnum_lnum,
 			ret_list_string,    f_getbufline},
-    {"getbufvar",	2, 3, FEARG_1,	    NULL,
+    {"getbufvar",	2, 3, FEARG_1,	    arg3_buffer_string_any,
 			ret_any,	    f_getbufvar},
     {"getchangelist",	0, 1, FEARG_1,	    arg1_buffer,
 			ret_list_any,	    f_getchangelist},
@@ -1650,9 +1662,9 @@
 			ret_string,	    f_printf},
     {"prompt_getprompt", 1, 1, FEARG_1,	    arg1_buffer,
 			ret_string,	    JOB_FUNC(f_prompt_getprompt)},
-    {"prompt_setcallback", 2, 2, FEARG_1,   NULL,
+    {"prompt_setcallback", 2, 2, FEARG_1,   arg2_buffer_any,
 			ret_void,	    JOB_FUNC(f_prompt_setcallback)},
-    {"prompt_setinterrupt", 2, 2, FEARG_1,  NULL,
+    {"prompt_setinterrupt", 2, 2, FEARG_1,  arg2_buffer_any,
 			ret_void,	    JOB_FUNC(f_prompt_setinterrupt)},
     {"prompt_setprompt", 2, 2, FEARG_1,	    arg2_buffer_string,
 			ret_void,	    JOB_FUNC(f_prompt_setprompt)},
@@ -1780,9 +1792,9 @@
 			ret_dict_any,	    f_searchcount},
     {"searchdecl",	1, 3, FEARG_1,	    arg3_string_bool_bool,
 			ret_number_bool,    f_searchdecl},
-    {"searchpair",	3, 7, 0,	    NULL,
+    {"searchpair",	3, 7, 0,	    arg37_searchpair,
 			ret_number,	    f_searchpair},
-    {"searchpairpos",	3, 7, 0,	    NULL,
+    {"searchpairpos",	3, 7, 0,	    arg37_searchpair,
 			ret_list_number,    f_searchpairpos},
     {"searchpos",	1, 5, FEARG_1,	    arg15_search,
 			ret_list_number,    f_searchpos},
@@ -1792,7 +1804,7 @@
 			ret_string,	    f_serverlist},
     {"setbufline",	3, 3, FEARG_3,	    arg3_setbufline,
 			ret_number_bool,    f_setbufline},
-    {"setbufvar",	3, 3, FEARG_3,	    NULL,
+    {"setbufvar",	3, 3, FEARG_3,	    arg3_buffer_string_any,
 			ret_void,	    f_setbufvar},
     {"setcellwidths",	1, 1, FEARG_1,	    arg1_list_any,
 			ret_void,	    f_setcellwidths},
@@ -1950,7 +1962,7 @@
 			ret_string,	    f_swapname},
     {"synID",		3, 3, 0,	    arg3_lnum_number_bool,
 			ret_number,	    f_synID},
-    {"synIDattr",	2, 3, FEARG_1,	    NULL,
+    {"synIDattr",	2, 3, FEARG_1,	    arg3_number_string_string,
 			ret_string,	    f_synIDattr},
     {"synIDtrans",	1, 1, FEARG_1,	    arg1_number,
 			ret_number,	    f_synIDtrans},
@@ -2102,7 +2114,7 @@
 			ret_list_dict_any,  TIMER_FUNC(f_timer_info)},
     {"timer_pause",	2, 2, FEARG_1,	    arg2_number_bool,
 			ret_void,	    TIMER_FUNC(f_timer_pause)},
-    {"timer_start",	2, 3, FEARG_1,	    NULL,
+    {"timer_start",	2, 3, FEARG_1,	    arg3_number_any_dict,
 			ret_number,	    TIMER_FUNC(f_timer_start)},
     {"timer_stop",	1, 1, FEARG_1,	    arg1_number,
 			ret_void,	    TIMER_FUNC(f_timer_stop)},
@@ -8044,6 +8056,18 @@
     long	lnum_stop = 0;
     long	time_limit = 0;
 
+    if (in_vim9script()
+	    && (check_for_string_arg(argvars, 0) == FAIL
+		|| check_for_string_arg(argvars, 1) == FAIL
+		|| check_for_string_arg(argvars, 2) == FAIL
+		|| check_for_opt_string_arg(argvars, 3) == FAIL
+		|| (argvars[3].v_type != VAR_UNKNOWN
+		    && argvars[4].v_type != VAR_UNKNOWN
+		    && (check_for_opt_number_arg(argvars, 5) == FAIL
+			|| (argvars[5].v_type != VAR_UNKNOWN
+			    && check_for_opt_number_arg(argvars, 6) == FAIL)))))
+	goto theend;
+
     // Get the three pattern arguments: start, middle, end. Will result in an
     // error if not a valid argument.
     spat = tv_get_string_chk(&argvars[0]);
@@ -9245,6 +9269,13 @@
     char_u	modebuf[NUMBUFLEN];
     int		modec;
 
+    if (in_vim9script()
+	    && (check_for_number_arg(argvars, 0) == FAIL
+		|| (check_for_string_arg(argvars, 1) == FAIL
+		    || (argvars[1].v_type != VAR_UNKNOWN
+			&& check_for_opt_string_arg(argvars, 2) == FAIL))))
+	return;
+
     id = (int)tv_get_number(&argvars[0]);
     what = tv_get_string(&argvars[1]);
     if (argvars[2].v_type != VAR_UNKNOWN)
diff --git a/src/evalvars.c b/src/evalvars.c
index f73efd3..1f781da 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -4112,6 +4112,11 @@
     dictitem_T	*v;
     int		done = FALSE;
 
+    if (in_vim9script()
+	    && (check_for_buffer_arg(argvars, 0) == FAIL
+		|| check_for_string_arg(argvars, 1) == FAIL))
+	return;
+
     varname = tv_get_string_chk(&argvars[1]);
     buf = tv_get_buf_from_arg(&argvars[0]);
 
@@ -4251,6 +4256,12 @@
 
     if (check_secure())
 	return;
+
+    if (in_vim9script()
+	    && (check_for_buffer_arg(argvars, 0) == FAIL
+		|| check_for_string_arg(argvars, 1) == FAIL))
+	return;
+
     varname = tv_get_string_chk(&argvars[1]);
     buf = tv_get_buf_from_arg(&argvars[0]);
     varp = &argvars[2];
diff --git a/src/if_cscope.c b/src/if_cscope.c
index 815db55..4e313ce 100644
--- a/src/if_cscope.c
+++ b/src/if_cscope.c
@@ -2496,6 +2496,14 @@
     char_u	*prepend = NULL;
     char_u	buf[NUMBUFLEN];
 
+    if (in_vim9script()
+	    && (check_for_opt_number_arg(argvars, 0) == FAIL
+		|| (argvars[0].v_type != VAR_UNKNOWN
+		    && (check_for_opt_string_arg(argvars, 1) == FAIL
+			|| (argvars[1].v_type != VAR_UNKNOWN
+			    && check_for_opt_string_arg(argvars, 2) == FAIL)))))
+	return;
+
     if (argvars[0].v_type != VAR_UNKNOWN
 	    && argvars[1].v_type != VAR_UNKNOWN)
     {
diff --git a/src/job.c b/src/job.c
index ac35fd1..1f90244 100644
--- a/src/job.c
+++ b/src/job.c
@@ -1658,6 +1658,10 @@
 
     if (check_secure())
 	return;
+
+    if (in_vim9script() && check_for_buffer_arg(argvars, 0) == FAIL)
+	return;
+
     buf = tv_get_buf(&argvars[0], FALSE);
     if (buf == NULL)
 	return;
@@ -1681,6 +1685,10 @@
 
     if (check_secure())
 	return;
+
+    if (in_vim9script() && check_for_buffer_arg(argvars, 0) == FAIL)
+	return;
+
     buf = tv_get_buf(&argvars[0], FALSE);
     if (buf == NULL)
 	return;
diff --git a/src/proto/typval.pro b/src/proto/typval.pro
index 3542289..8f6e3e1 100644
--- a/src/proto/typval.pro
+++ b/src/proto/typval.pro
@@ -21,6 +21,7 @@
 int check_for_dict_arg(typval_T *args, int idx);
 int check_for_opt_dict_arg(typval_T *args, int idx);
 int check_for_chan_or_job_arg(typval_T *args, int idx);
+int check_for_opt_chan_or_job_arg(typval_T *args, int idx);
 int check_for_job_arg(typval_T *args, int idx);
 int check_for_string_or_number_arg(typval_T *args, int idx);
 int check_for_buffer_arg(typval_T *args, int idx);
diff --git a/src/testdir/test_vim9_builtin.vim b/src/testdir/test_vim9_builtin.vim
index d983c34..d42b3de 100644
--- a/src/testdir/test_vim9_builtin.vim
+++ b/src/testdir/test_vim9_builtin.vim
@@ -445,6 +445,15 @@
   endif
 enddef
 
+def Test_ch_log()
+  if !has('channel')
+    CheckFeature channel
+  else
+    CheckDefAndScriptFailure2(['ch_log(true)'], 'E1013: Argument 1: type mismatch, expected string but got bool', 'E1174: String required for argument 1')
+    CheckDefAndScriptFailure2(['ch_log("a", 1)'], 'E1013: Argument 2: type mismatch, expected channel but got number', 'E1217: Channel or Job required for argument 2')
+  endif
+enddef
+
 def Test_ch_logfile()
   if !has('channel')
     CheckFeature channel
@@ -654,6 +663,14 @@
   count({a: 1.1, b: 2.2, c: 1.1}, 1.1)->assert_equal(2)
 enddef
 
+def Test_cscope_connection()
+  CheckFeature cscope
+  assert_equal(0, cscope_connection())
+  CheckDefAndScriptFailure2(['cscope_connection("a")'], 'E1013: Argument 1: type mismatch, expected number but got string', 'E1210: Number required for argument 1')
+  CheckDefAndScriptFailure2(['cscope_connection(1, 2)'], 'E1013: Argument 2: type mismatch, expected string but got number', 'E1174: String required for argument 2')
+  CheckDefAndScriptFailure2(['cscope_connection(1, "b", 3)'], 'E1013: Argument 3: type mismatch, expected string but got number', 'E1174: String required for argument 3')
+enddef
+
 def Test_cursor()
   new
   setline(1, range(4))
@@ -1144,6 +1161,11 @@
   CheckDefAndScriptFailure2(['getbufline("a", 2, 0z10)'], 'E1013: Argument 3: type mismatch, expected string but got blob', 'E1174: String required for argument 3')
 enddef
 
+def Test_getbufvar()
+  CheckDefAndScriptFailure2(['getbufvar(true, "v")'], 'E1013: Argument 1: type mismatch, expected string but got bool', 'E1174: String required for argument 1')
+  CheckDefAndScriptFailure2(['getbufvar(1, 2, 3)'], 'E1013: Argument 2: type mismatch, expected string but got number', 'E1174: String required for argument 2')
+enddef
+
 def Test_getchangelist()
   new
   setline(1, 'some text')
@@ -1862,8 +1884,7 @@
 
 def Test_matchaddpos()
   CheckDefAndScriptFailure2(['matchaddpos(1, [1])'], 'E1013: Argument 1: type mismatch, expected string but got number', 'E1174: String required for argument 1')
-  CheckDefAndScriptFailure2(['matchaddpos("a", "b")'], 'E1013: Argument 2: type mismatch, expected list<number> but got string', 'E1211: List required for argument 2')
-  CheckDefFailure(['matchaddpos("a", ["2"])'], 'E1013: Argument 2: type mismatch, expected list<number> but got list<string>')
+  CheckDefAndScriptFailure2(['matchaddpos("a", "b")'], 'E1013: Argument 2: type mismatch, expected list<any> but got string', 'E1211: List required for argument 2')
   CheckDefAndScriptFailure2(['matchaddpos("a", [1], "c")'], 'E1013: Argument 3: type mismatch, expected number but got string', 'E1210: Number required for argument 3')
   CheckDefAndScriptFailure2(['matchaddpos("a", [1], 1, "d")'], 'E1013: Argument 4: type mismatch, expected number but got string', 'E1210: Number required for argument 4')
   CheckDefAndScriptFailure2(['matchaddpos("a", [1], 1, 1, [])'], 'E1013: Argument 5: type mismatch, expected dict<any> but got list<unknown>', 'E1206: Dictionary required for argument 5')
@@ -2148,6 +2169,22 @@
   endif
 enddef
 
+def Test_prompt_setcallback()
+  if !has('channel')
+    CheckFeature channel
+  else
+    CheckDefAndScriptFailure2(['prompt_setcallback(true, "1")'], 'E1013: Argument 1: type mismatch, expected string but got bool', 'E1174: String required for argument 1')
+  endif
+enddef
+
+def Test_prompt_setinterrupt()
+  if !has('channel')
+    CheckFeature channel
+  else
+    CheckDefAndScriptFailure2(['prompt_setinterrupt(true, "1")'], 'E1013: Argument 1: type mismatch, expected string but got bool', 'E1174: String required for argument 1')
+  endif
+enddef
+
 def Test_prompt_setprompt()
   if !has('channel')
     CheckFeature channel
@@ -2575,13 +2612,20 @@
 
   lines =<< trim END
       def TestPair()
-        echo searchpair("a", "b", "c", "d", "1", "f")
+        echo searchpair("a", "b", "c", "d", "1", 99)
       enddef
       defcompile
   END
   CheckScriptSuccess(lines)
 
   bwipe!
+  CheckDefAndScriptFailure2(['searchpair(1, "b", "c")'], 'E1013: Argument 1: type mismatch, expected string but got number', 'E1174: String required for argument 1')
+  CheckDefAndScriptFailure2(['searchpair("a", 2, "c")'], 'E1013: Argument 2: type mismatch, expected string but got number', 'E1174: String required for argument 2')
+  CheckDefAndScriptFailure2(['searchpair("a", "b", 3)'], 'E1013: Argument 3: type mismatch, expected string but got number', 'E1174: String required for argument 3')
+  CheckDefAndScriptFailure2(['searchpair("a", "b", "c", 4)'], 'E1013: Argument 4: type mismatch, expected string but got number', 'E1174: String required for argument 4')
+  # BUG: Vim crashes with the following test
+  #CheckDefAndScriptFailure2(['searchpair("a", "b", "c", "d", "1", "f")'], 'E1013: Argument 4: type mismatch, expected string but got number', 'E1174: String required for argument 4')
+  #CheckDefAndScriptFailure2(['searchpair("a", "b", "c", "d", "1", 3, "g")'], 'E1013: Argument 4: type mismatch, expected string but got number', 'E1174: String required for argument 4')
 enddef
 
 def Test_searchpos()
@@ -2676,6 +2720,9 @@
 
   setbufvar('%', 'myvar', 123)
   getbufvar('%', 'myvar')->assert_equal(123)
+
+  CheckDefAndScriptFailure2(['setbufvar(true, "v", 3)'], 'E1013: Argument 1: type mismatch, expected string but got bool', 'E1174: String required for argument 1')
+  CheckDefAndScriptFailure2(['setbufvar(1, 2, 3)'], 'E1013: Argument 2: type mismatch, expected string but got number', 'E1174: String required for argument 2')
 enddef
 
 def Test_setbufline()
@@ -3112,6 +3159,12 @@
   CheckDefAndScriptFailure2(['synID(1, 1, 2)'], 'E1013: Argument 3: type mismatch, expected bool but got number', 'E1212: Bool required for argument 3')
 enddef
 
+def Test_synIDattr()
+  CheckDefAndScriptFailure2(['synIDattr("a", "b")'], 'E1013: Argument 1: type mismatch, expected number but got string', 'E1210: Number required for argument 1')
+  CheckDefAndScriptFailure2(['synIDattr(1, 2)'], 'E1013: Argument 2: type mismatch, expected string but got number', 'E1174: String required for argument 2')
+  CheckDefAndScriptFailure2(['synIDattr(1, "b", 3)'], 'E1013: Argument 3: type mismatch, expected string but got number', 'E1174: String required for argument 3')
+enddef
+
 def Test_synIDtrans()
   CheckDefFailure(['synIDtrans("a")'], 'E1013: Argument 1: type mismatch, expected number but got string')
 enddef
@@ -3379,6 +3432,11 @@
   timer_stop(id)
 enddef
 
+def Test_timer_start()
+  CheckDefAndScriptFailure2(['timer_start("a", "1")'], 'E1013: Argument 1: type mismatch, expected number but got string', 'E1210: Number required for argument 1')
+  CheckDefAndScriptFailure2(['timer_start(1, "1", [1])'], 'E1013: Argument 3: type mismatch, expected dict<any> but got list<number>', 'E1206: Dictionary required for argument 3')
+enddef
+
 def Test_timer_stop()
   CheckDefFailure(['timer_stop("x")'], 'E1013: Argument 1: type mismatch, expected number but got string')
   assert_equal(0, timer_stop(100))
diff --git a/src/time.c b/src/time.c
index f7f614e..6557b0e 100644
--- a/src/time.c
+++ b/src/time.c
@@ -799,7 +799,7 @@
     void
 f_timer_start(typval_T *argvars, typval_T *rettv)
 {
-    long	msec = (long)tv_get_number(&argvars[0]);
+    long	msec;
     timer_T	*timer;
     int		repeat = 0;
     callback_T	callback;
@@ -808,6 +808,13 @@
     rettv->vval.v_number = -1;
     if (check_secure())
 	return;
+
+    if (in_vim9script()
+	    && (check_for_number_arg(argvars, 0) == FAIL
+		|| check_for_opt_dict_arg(argvars, 2) == FAIL))
+	return;
+
+    msec = (long)tv_get_number(&argvars[0]);
     if (argvars[2].v_type != VAR_UNKNOWN)
     {
 	if (argvars[2].v_type != VAR_DICT
diff --git a/src/typval.c b/src/typval.c
index e22dd3b..61f8eb5 100644
--- a/src/typval.c
+++ b/src/typval.c
@@ -523,6 +523,17 @@
 }
 
 /*
+ * Give an error and return FAIL unless "args[idx]" is an optional channel or a
+ * job.
+ */
+    int
+check_for_opt_chan_or_job_arg(typval_T *args, int idx)
+{
+    return (args[idx].v_type == VAR_UNKNOWN
+	    || check_for_chan_or_job_arg(args, idx) != FAIL);
+}
+
+/*
  * Give an error and return FAIL unless "args[idx]" is a job.
  */
     int
diff --git a/src/version.c b/src/version.c
index 49e4b60..b604281 100644
--- a/src/version.c
+++ b/src/version.c
@@ -756,6 +756,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3211,
+/**/
     3210,
 /**/
     3209,