diff --git a/src/evalbuffer.c b/src/evalbuffer.c
index 8a6c52d..6f552c7 100644
--- a/src/evalbuffer.c
+++ b/src/evalbuffer.c
@@ -387,6 +387,12 @@
     int		error = FALSE;
     char_u	*name;
 
+    if (in_vim9script()
+	    && (check_for_opt_string_or_number_arg(argvars, 0) == FAIL
+		|| (argvars[0].v_type != VAR_UNKNOWN
+		    && check_for_opt_bool_arg(argvars, 1) == FAIL)))
+	return;
+
     if (argvars[0].v_type == VAR_UNKNOWN)
 	buf = curbuf;
     else
@@ -459,6 +465,12 @@
     tabpage_T	*tp;
     win_T	*wp;
 
+    if (in_vim9script()
+	    && (check_for_buffer_arg(argvars, 0) == FAIL
+		|| check_for_lnum_arg(argvars, 1) == FAIL
+		|| check_for_opt_lnum_arg(argvars, 2) == FAIL))
+	return;
+
     buf = tv_get_buf(&argvars[0], FALSE);
     if (buf == NULL)
     {
@@ -727,6 +739,12 @@
     linenr_T	end = 1;
     buf_T	*buf;
 
+    if (in_vim9script()
+	    && (check_for_buffer_arg(argvars, 0) == FAIL
+		|| check_for_lnum_arg(argvars, 1) == FAIL
+		|| check_for_opt_lnum_arg(argvars, 2) == FAIL))
+	return;
+
     buf = tv_get_buf_from_arg(&argvars[0]);
     if (buf != NULL)
     {