diff --git a/src/evalfunc.c b/src/evalfunc.c
index 8057408..d78589c 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -533,6 +533,26 @@
 }
 
 /*
+ * Check an expression argument, can be a string, funcref or partial.
+ * Also accept a bool, a constant resulting from compiling a string argument.
+ * Also accept a number, one and zero are accepted.
+ */
+    static int
+arg_string_or_func(type_T *type, argcontext_T *context)
+{
+    if (type->tt_type == VAR_ANY
+	    || type->tt_type == VAR_UNKNOWN
+	    || type->tt_type == VAR_STRING
+	    || type->tt_type == VAR_PARTIAL
+	    || type->tt_type == VAR_FUNC
+	    || type->tt_type == VAR_BOOL
+	    || type->tt_type == VAR_NUMBER)
+	return OK;
+    arg_type_mismatch(&t_func_any, type, context->arg_idx + 1);
+    return FAIL;
+}
+
+/*
  * Check "type" is a list of 'any' or a blob or a string.
  */
     static int
@@ -916,8 +936,8 @@
 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 arg15_search[] = {arg_string, arg_string, arg_number, arg_number, arg_string_or_func};
+static argcheck_T arg37_searchpair[] = {arg_string, arg_string, arg_string, arg_string, arg_string_or_func, 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};