diff --git a/vlib/v/ast/table.v b/vlib/v/ast/table.v
index 8a75cb7d78..391437dd88 100644
--- a/vlib/v/ast/table.v
+++ b/vlib/v/ast/table.v
@@ -180,7 +180,8 @@ pub fn (t &Table) fn_type_signature(f &Fn) string {
 		// TODO: for now ignore mut/pts in sig for now
 		typ := arg.typ.set_nr_muls(0)
 		arg_type_sym := t.get_type_symbol(typ)
-		sig += '$arg_type_sym.kind'
+		sig += arg_type_sym.str().to_lower().replace_each(['.', '__', '&', '', '[]', 'arr_', 'chan ',
+			'chan_', 'map[', 'map_of_', ']', '_to_'])
 		if i < f.params.len - 1 {
 			sig += '_'
 		}