diff --git a/src/evalfunc.c b/src/evalfunc.c
index 4456f69..f065026 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -422,6 +422,21 @@
 }
 
 /*
+ * Check "type" is a string or a dict of 'any'
+ */
+    static int
+arg_string_or_dict_any(type_T *type, type_T *decl_type UNUSED, argcontext_T *context)
+{
+    if (type->tt_type == VAR_ANY
+	    || type->tt_type == VAR_UNKNOWN
+	    || type->tt_type == VAR_STRING
+	    || type->tt_type == VAR_DICT)
+	return OK;
+    arg_type_mismatch(&t_string, type, context->arg_idx + 1);
+    return FAIL;
+}
+
+/*
  * Check "type" is a string or a blob
  */
     static int
@@ -998,8 +1013,8 @@
 static argcheck_T arg3_string_any_dict[] = {arg_string, NULL, arg_dict_any};
 static argcheck_T arg3_string_any_string[] = {arg_string, NULL, arg_string};
 static argcheck_T arg3_string_bool_bool[] = {arg_string, arg_bool, arg_bool};
-static argcheck_T arg3_string_bool_dict[] = {arg_string, arg_bool, arg_dict_any};
 static argcheck_T arg3_string_number_bool[] = {arg_string, arg_number, arg_bool};
+static argcheck_T arg3_string_or_dict_bool_dict[] = {arg_string_or_dict_any, arg_bool, arg_dict_any};
 static argcheck_T arg3_string_string_bool[] = {arg_string, arg_string, arg_bool};
 static argcheck_T arg3_string_string_dict[] = {arg_string, arg_string, arg_dict_any};
 static argcheck_T arg3_string_string_number[] = {arg_string, arg_string, arg_number};
@@ -2053,7 +2068,7 @@
 			ret_list_dict_any,  f_maplist},
     {"mapnew",		2, 2, FEARG_1,	    arg2_mapnew,
 			ret_first_cont,	    f_mapnew},
-    {"mapset",		3, 3, FEARG_1,	    arg3_string_bool_dict,
+    {"mapset",		1, 3, FEARG_1,	    arg3_string_or_dict_bool_dict,
 			ret_void,	    f_mapset},
     {"match",		2, 4, FEARG_1,	    arg24_match_func,
 			ret_any,	    f_match},