diff --git a/src/evalfunc.c b/src/evalfunc.c
index 9b3bdf7..67a1427 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -1148,6 +1148,7 @@
 static argcheck_T arg3_buffer_string_any[] = {arg_buffer, arg_string, arg_any};
 static argcheck_T arg3_buffer_string_dict[] = {arg_buffer, arg_string, arg_dict_any};
 static argcheck_T arg3_dict_number_number[] = {arg_dict_any, arg_number, arg_number};
+static argcheck_T arg3_diff[] = {arg_list_string, arg_list_string, arg_dict_any};
 static argcheck_T arg3_list_string_dict[] = {arg_list_any, arg_string, arg_dict_any};
 static argcheck_T arg3_lnum_number_bool[] = {arg_lnum, arg_number, arg_bool};
 static argcheck_T arg3_number[] = {arg_number, arg_number, arg_number};
@@ -1950,6 +1951,8 @@
 			ret_number_bool,    f_deletebufline},
     {"did_filetype",	0, 0, 0,	    NULL,
 			ret_number_bool,    f_did_filetype},
+    {"diff",		2, 3, FEARG_1,	    arg3_diff,
+			ret_list_dict_any,  f_diff},
     {"diff_filler",	1, 1, FEARG_1,	    arg1_lnum,
 			ret_number,	    f_diff_filler},
     {"diff_hlID",	2, 2, FEARG_1,	    arg2_lnum_number,