diff --git a/src/dict.c b/src/dict.c
index 8bcf28c..080c345 100644
--- a/src/dict.c
+++ b/src/dict.c
@@ -1073,7 +1073,7 @@
  * Otherwise duplicate keys are ignored ("action" is "keep").
  */
     void
-dict_extend(dict_T *d1, dict_T *d2, char_u *action)
+dict_extend(dict_T *d1, dict_T *d2, char_u *action, char *func_name)
 {
     dictitem_T	*di1;
     hashitem_T	*hi2;
@@ -1106,8 +1106,8 @@
 	    }
 
 	    if (type != NULL
-		     && check_typval_arg_type(type, &HI2DI(hi2)->di_tv, 0)
-								       == FAIL)
+		     && check_typval_arg_type(type, &HI2DI(hi2)->di_tv,
+							 func_name, 0) == FAIL)
 		break;
 
 	    if (di1 == NULL)
diff --git a/src/errors.h b/src/errors.h
index 8655d3f..281bda6 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -192,8 +192,12 @@
 	INIT(= N_("E1011: Name too long: %s"));
 EXTERN char e_type_mismatch_expected_str_but_got_str[]
 	INIT(= N_("E1012: Type mismatch; expected %s but got %s"));
+EXTERN char e_type_mismatch_expected_str_but_got_str_in_str[]
+	INIT(= N_("E1012: Type mismatch; expected %s but got %s in %s"));
 EXTERN char e_argument_nr_type_mismatch_expected_str_but_got_str[]
 	INIT(= N_("E1013: Argument %d: type mismatch, expected %s but got %s"));
+EXTERN char e_argument_nr_type_mismatch_expected_str_but_got_str_in_str[]
+	INIT(= N_("E1013: Argument %d: type mismatch, expected %s but got %s in %s"));
 EXTERN char e_invalid_key_str[]
 	INIT(= N_("E1014: Invalid key: %s"));
 EXTERN char e_name_expected_str[]
@@ -494,6 +498,8 @@
 	INIT(= N_("E1162: Register name must be one character: %s"));
 EXTERN char e_variable_nr_type_mismatch_expected_str_but_got_str[]
 	INIT(= N_("E1163: Variable %d: type mismatch, expected %s but got %s"));
+EXTERN char e_variable_nr_type_mismatch_expected_str_but_got_str_in_str[]
+	INIT(= N_("E1163: Variable %d: type mismatch, expected %s but got %s in %s"));
 EXTERN char e_vim9cmd_must_be_followed_by_command[]
 	INIT(= N_("E1164: vim9cmd must be followed by a command"));
 EXTERN char e_cannot_use_range_with_assignment_str[]
diff --git a/src/eval.c b/src/eval.c
index a5c889a..bfe9f61 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1365,8 +1365,8 @@
 	}
 	else
 	{
-	    if (lp->ll_type != NULL
-		       && check_typval_arg_type(lp->ll_type, rettv, 0) == FAIL)
+	    if (lp->ll_type != NULL && check_typval_arg_type(lp->ll_type, rettv,
+							      NULL, 0) == FAIL)
 		return;
 	    set_var_const(lp->ll_name, lp->ll_type, rettv, copy,
 							       flags, var_idx);
@@ -1450,7 +1450,8 @@
 	}
 
 	if (lp->ll_valtype != NULL
-		    && check_typval_arg_type(lp->ll_valtype, rettv, 0) == FAIL)
+		    && check_typval_arg_type(lp->ll_valtype, rettv,
+							      NULL, 0) == FAIL)
 	    return;
 
 	if (lp->ll_newkey != NULL)
diff --git a/src/if_py_both.h b/src/if_py_both.h
index 7f38e17..6d71ac1 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -2043,7 +2043,7 @@
 	    return NULL;
 
 	VimTryStart();
-	dict_extend(self->dict, tv.vval.v_dict, (char_u *) "force");
+	dict_extend(self->dict, tv.vval.v_dict, (char_u *) "force", NULL);
 	clear_tv(&tv);
 	if (VimTryEnd())
 	    return NULL;
diff --git a/src/list.c b/src/list.c
index 55b9fa0..c59197b 100644
--- a/src/list.c
+++ b/src/list.c
@@ -605,7 +605,8 @@
     listitem_T	*li;
 
     if (l->lv_type != NULL && l->lv_type->tt_member != NULL
-		&& check_typval_arg_type(l->lv_type->tt_member, tv, 0) == FAIL)
+		&& check_typval_arg_type(l->lv_type->tt_member, tv,
+							      NULL, 0) == FAIL)
 	return FAIL;
     li = listitem_alloc();
     if (li == NULL)
@@ -722,7 +723,8 @@
     listitem_T	*ni;
 
     if (l->lv_type != NULL && l->lv_type->tt_member != NULL
-		&& check_typval_arg_type(l->lv_type->tt_member, tv, 0) == FAIL)
+		&& check_typval_arg_type(l->lv_type->tt_member, tv,
+							      NULL, 0) == FAIL)
 	return FAIL;
     ni = listitem_alloc();
     if (ni == NULL)
@@ -2085,9 +2087,9 @@
     blob_T	*b = NULL;
     int		rem;
     int		todo;
-    char_u	*ermsg = (char_u *)(filtermap == FILTERMAP_MAP ? "map()"
+    char	*func_name = filtermap == FILTERMAP_MAP ? "map()"
 				  : filtermap == FILTERMAP_MAPNEW ? "mapnew()"
-				  : "filter()");
+				  : "filter()";
     char_u	*arg_errmsg = (char_u *)(filtermap == FILTERMAP_MAP
 							 ? N_("map() argument")
 				       : filtermap == FILTERMAP_MAPNEW
@@ -2144,7 +2146,7 @@
     }
     else
     {
-	semsg(_(e_listdictblobarg), ermsg);
+	semsg(_(e_listdictblobarg), func_name);
 	goto theend;
     }
 
@@ -2210,7 +2212,8 @@
 		    if (filtermap == FILTERMAP_MAP)
 		    {
 			if (type != NULL && check_typval_arg_type(
-					   type->tt_member, &newtv, 0) == FAIL)
+				     type->tt_member, &newtv,
+							 func_name, 0) == FAIL)
 			{
 			    clear_tv(&newtv);
 			    break;
@@ -2345,7 +2348,8 @@
 		    {
 			if (filtermap == FILTERMAP_MAP && type != NULL
 				      && check_typval_arg_type(
-					   type->tt_member, &newtv, 0) == FAIL)
+				     type->tt_member, &newtv,
+							 func_name, 0) == FAIL)
 			{
 			    clear_tv(&newtv);
 			    break;
@@ -2389,7 +2393,7 @@
 		    if (filtermap == FILTERMAP_MAP)
 		    {
 			if (type != NULL && check_typval_arg_type(
-					   type->tt_member, &newtv, 0) == FAIL)
+				type->tt_member, &newtv, func_name, 0) == FAIL)
 			{
 			    clear_tv(&newtv);
 			    break;
@@ -2627,6 +2631,7 @@
 {
     type_T	*type = NULL;
     garray_T	type_list;
+    char	*func_name = is_new ? "extendnew()" : "extend()";
 
     if (!is_new && in_vim9script())
     {
@@ -2680,7 +2685,7 @@
 	    else
 		item = NULL;
 	    if (type != NULL && check_typval_arg_type(
-						 type, &argvars[1], 2) == FAIL)
+				      type, &argvars[1], func_name, 2) == FAIL)
 		goto theend;
 	    list_extend(l1, l2, item);
 
@@ -2737,10 +2742,10 @@
 	    else
 		action = (char_u *)"force";
 
-	    if (type != NULL && check_typval_arg_type(
-						 type, &argvars[1], 2) == FAIL)
+	    if (type != NULL && check_typval_arg_type(type, &argvars[1],
+							 func_name, 2) == FAIL)
 		goto theend;
-	    dict_extend(d1, d2, action);
+	    dict_extend(d1, d2, action, func_name);
 
 	    if (is_new)
 	    {
@@ -2753,7 +2758,7 @@
 	}
     }
     else
-	semsg(_(e_listdictarg), is_new ? "extendnew()" : "extend()");
+	semsg(_(e_listdictarg), func_name);
 
 theend:
     if (type != NULL)
diff --git a/src/proto/dict.pro b/src/proto/dict.pro
index 7789d4c..5d76385 100644
--- a/src/proto/dict.pro
+++ b/src/proto/dict.pro
@@ -37,7 +37,7 @@
 char_u *skip_literal_key(char_u *key);
 char_u *get_literal_key(char_u **arg);
 int eval_dict(char_u **arg, typval_T *rettv, evalarg_T *evalarg, int literal);
-void dict_extend(dict_T *d1, dict_T *d2, char_u *action);
+void dict_extend(dict_T *d1, dict_T *d2, char_u *action, char *func_name);
 dictitem_T *dict_lookup(hashitem_T *hi);
 int dict_equal(dict_T *d1, dict_T *d2, int ic, int recursive);
 void f_items(typval_T *argvars, typval_T *rettv);
diff --git a/src/proto/vim9type.pro b/src/proto/vim9type.pro
index a512fa4..559eb5c 100644
--- a/src/proto/vim9type.pro
+++ b/src/proto/vim9type.pro
@@ -11,7 +11,7 @@
 int need_convert_to_bool(type_T *type, typval_T *tv);
 type_T *typval2type(typval_T *tv, int copyID, garray_T *type_gap, int do_member);
 type_T *typval2type_vimvar(typval_T *tv, garray_T *type_gap);
-int check_typval_arg_type(type_T *expected, typval_T *actual_tv, int arg_idx);
+int check_typval_arg_type(type_T *expected, typval_T *actual_tv, char *func_name, int arg_idx);
 int check_typval_type(type_T *expected, typval_T *actual_tv, where_T where);
 void type_mismatch(type_T *expected, type_T *actual);
 void arg_type_mismatch(type_T *expected, type_T *actual, int arg_idx);
diff --git a/src/structs.h b/src/structs.h
index 5331183..265fe02 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -4438,7 +4438,10 @@
 
 // Struct used to pass to error messages about where the error happened.
 typedef struct {
+    char    *wt_func_name;  // function name or NULL
     char    wt_index;	    // argument or variable index, 0 means unknown
     char    wt_variable;    // "variable" when TRUE, "argument" otherwise
 } where_T;
 
+#define WHERE_INIT {NULL, 0, 0}
+
diff --git a/src/testdir/test_vim9_builtin.vim b/src/testdir/test_vim9_builtin.vim
index fb9c868..741e74a 100644
--- a/src/testdir/test_vim9_builtin.vim
+++ b/src/testdir/test_vim9_builtin.vim
@@ -795,6 +795,8 @@
 
   CheckDefFailure(['extend([1], ["b"])'], 'E1013: Argument 2: type mismatch, expected list<number> but got list<string>')
   CheckDefExecFailure(['extend([1], ["b", 1])'], 'E1013: Argument 2: type mismatch, expected list<number> but got list<any>')
+
+  CheckScriptFailure(['vim9script', 'extend([1], ["b", 1])'], 'E1013: Argument 2: type mismatch, expected list<number> but got list<any> in extend()')
 enddef
 
 func g:ExtendDict(d)
@@ -1741,19 +1743,19 @@
     var l: list<number> = [0]
     echo map(l, (_, v) => [])
   END
-  CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected number but got list<unknown>', 2)
+  CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected number but got list<unknown> in map()', 2)
 
   lines =<< trim END
     var l: list<number> = range(2)
     echo map(l, (_, v) => [])
   END
-  CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected number but got list<unknown>', 2)
+  CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected number but got list<unknown> in map()', 2)
 
   lines =<< trim END
     var d: dict<number> = {key: 0}
     echo map(d, (_, v) => [])
   END
-  CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected number but got list<unknown>', 2)
+  CheckDefExecAndScriptFailure(lines, 'E1012: Type mismatch; expected number but got list<unknown> in map()', 2)
 enddef
 
 def Test_maparg()
diff --git a/src/version.c b/src/version.c
index cd0f9ec..02469ed 100644
--- a/src/version.c
+++ b/src/version.c
@@ -756,6 +756,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3200,
+/**/
     3199,
 /**/
     3198,
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 8e8ae3f..4f7a039 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -1033,7 +1033,7 @@
 	int	silent,
 	int	actual_is_const)
 {
-    where_T where;
+    where_T where = WHERE_INIT;
 
     if (expected == &t_bool && actual != &t_bool
 					&& (actual->tt_flags & TTFLAG_BOOL_OK))
@@ -1045,7 +1045,6 @@
     }
 
     where.wt_index = arg_idx;
-    where.wt_variable = FALSE;
     if (check_type(expected, actual, FALSE, where) == OK)
 	return OK;
 
@@ -2804,10 +2803,8 @@
     if (ppconst->pp_used > 0)
     {
 	typval_T    *tv = &ppconst->pp_tv[ppconst->pp_used - 1];
-	where_T	    where;
+	where_T	    where = WHERE_INIT;
 
-	where.wt_index = 0;
-	where.wt_variable = FALSE;
 	return check_typval_type(&t_bool, tv, where);
     }
     return OK;
@@ -4822,12 +4819,10 @@
     {
 	garray_T    *stack = &cctx->ctx_type_stack;
 	type_T	    *actual;
-	where_T	    where;
+	where_T	    where = WHERE_INIT;
 
 	generate_ppconst(cctx, ppconst);
 	actual = ((type_T **)stack->ga_data)[stack->ga_len - 1];
-	where.wt_index = 0;
-	where.wt_variable = FALSE;
 	if (check_type(want_type, actual, FALSE, where) == FAIL)
 	{
 	    if (need_type(actual, want_type, -1, 0, cctx, FALSE, FALSE) == FAIL)
@@ -7975,7 +7970,7 @@
 	int		vimvaridx = -1;
 	type_T		*type = &t_any;
 	type_T		*lhs_type = &t_any;
-	where_T		where;
+	where_T		where = WHERE_INIT;
 
 	p = skip_var_one(arg, FALSE);
 	varlen = p - arg;
@@ -9325,7 +9320,7 @@
 	    garray_T	*stack = &cctx.ctx_type_stack;
 	    type_T	*val_type;
 	    int		arg_idx = first_def_arg + i;
-	    where_T	where;
+	    where_T	where = WHERE_INIT;
 	    int		r;
 	    int		jump_instr_idx = instr->ga_len;
 	    isn_T	*isn;
@@ -9348,7 +9343,6 @@
 	    // specified type.
 	    val_type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
 	    where.wt_index = arg_idx + 1;
-	    where.wt_variable = FALSE;
 	    if (ufunc->uf_arg_types[arg_idx] == &t_unknown)
 	    {
 		did_set_arg_type = TRUE;
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 6cc1fc7..33ad788 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -730,15 +730,18 @@
     int		idx;
     int		did_emsg_before = did_emsg;
     ectx_T	*prev_ectx = current_ectx;
+    char	*save_func_name = ectx->ec_where.wt_func_name;
 
     if (call_prepare(argcount, argvars, ectx) == FAIL)
 	return FAIL;
+    ectx->ec_where.wt_func_name = internal_func_name(func_idx);
 
     // Call the builtin function.  Set "current_ectx" so that when it
     // recursively invokes call_def_function() a closure context can be set.
     current_ectx = ectx;
     call_internal_func_by_idx(func_idx, argvars, STACK_TV_BOT(-1));
     current_ectx = prev_ectx;
+    ectx->ec_where.wt_func_name = save_func_name;
 
     // Clear the arguments.
     for (idx = 0; idx < argcount; ++idx)
@@ -907,7 +910,7 @@
 		else if (ufunc->uf_va_type != NULL)
 		    type = ufunc->uf_va_type->tt_member;
 		if (type != NULL && check_typval_arg_type(type,
-						      &argv[i], i + 1) == FAIL)
+						&argv[i], NULL, i + 1) == FAIL)
 		    return FAIL;
 	    }
 	}
@@ -4535,7 +4538,8 @@
 	{
 	    if (ufunc->uf_arg_types != NULL && idx < ufunc->uf_args.ga_len
 		    && check_typval_arg_type(
-			ufunc->uf_arg_types[idx], &argv[idx], idx + 1) == FAIL)
+			ufunc->uf_arg_types[idx], &argv[idx],
+							NULL, idx + 1) == FAIL)
 		goto failed_early;
 	    copy_tv(&argv[idx], STACK_TV_BOT(0));
 	}
@@ -4567,7 +4571,7 @@
 	    for (idx = 0; idx < vararg_count; ++idx)
 	    {
 		if (check_typval_arg_type(expected, &li->li_tv,
-						       argc + idx + 1) == FAIL)
+						 NULL, argc + idx + 1) == FAIL)
 		    goto failed_early;
 		li = li->li_next;
 	    }
diff --git a/src/vim9type.c b/src/vim9type.c
index c4f3cd5..ea50e89 100644
--- a/src/vim9type.c
+++ b/src/vim9type.c
@@ -428,12 +428,16 @@
 }
 
     int
-check_typval_arg_type(type_T *expected, typval_T *actual_tv, int arg_idx)
+check_typval_arg_type(
+	type_T	    *expected,
+	typval_T    *actual_tv,
+	char	    *func_name,
+	int	    arg_idx)
 {
-    where_T	where;
+    where_T	where = WHERE_INIT;
 
     where.wt_index = arg_idx;
-    where.wt_variable = FALSE;
+    where.wt_func_name = func_name;
     return check_typval_type(expected, actual_tv, where);
 }
 
@@ -465,10 +469,9 @@
     void
 arg_type_mismatch(type_T *expected, type_T *actual, int arg_idx)
 {
-    where_T	where;
+    where_T	where = WHERE_INIT;
 
     where.wt_index = arg_idx;
-    where.wt_variable = FALSE;
     type_mismatch_where(expected, actual, where);
 }
 
@@ -481,14 +484,23 @@
 
     if (where.wt_index > 0)
     {
-	semsg(_(where.wt_variable
-			? e_variable_nr_type_mismatch_expected_str_but_got_str
-			: e_argument_nr_type_mismatch_expected_str_but_got_str),
+	if (where.wt_func_name == NULL)
+	    semsg(_(where.wt_variable
+			 ? e_variable_nr_type_mismatch_expected_str_but_got_str
+		       : e_argument_nr_type_mismatch_expected_str_but_got_str),
 					 where.wt_index, typename1, typename2);
+	else
+	    semsg(_(where.wt_variable
+		  ? e_variable_nr_type_mismatch_expected_str_but_got_str_in_str
+		: e_argument_nr_type_mismatch_expected_str_but_got_str_in_str),
+		     where.wt_index, typename1, typename2, where.wt_func_name);
     }
-    else
+    else if (where.wt_func_name == NULL)
 	semsg(_(e_type_mismatch_expected_str_but_got_str),
 							 typename1, typename2);
+    else
+	semsg(_(e_type_mismatch_expected_str_but_got_str_in_str),
+				     typename1, typename2, where.wt_func_name);
     vim_free(tofree1);
     vim_free(tofree2);
 }
@@ -604,7 +616,7 @@
 	    expected = type->tt_args[type->tt_argcount - 1]->tt_member;
 	else
 	    expected = type->tt_args[i];
-	if (check_typval_arg_type(expected, &argvars[i], i + 1) == FAIL)
+	if (check_typval_arg_type(expected, &argvars[i], NULL, i + 1) == FAIL)
 	    return FAIL;
     }
     return OK;