1 // PR c++/94819
2 // { dg-do compile { target concepts } }
3 
4 struct dna4 {};
5 struct rna4 {};
6 
7 template <typename component_types>
8 struct alphabet_tuple_base {
9     template <typename component_type>
__is_samealphabet_tuple_base10         requires __is_same(component_type, component_types)
11     alphabet_tuple_base(component_type) {}
12 };
13 
14 template <typename sequence_alphabet_t>
15 struct structured_rna : alphabet_tuple_base<sequence_alphabet_t> {
16     using base_type = alphabet_tuple_base<sequence_alphabet_t>;
17     using base_type::base_type;
18 };
19 
20 structured_rna<rna4> t2{dna4{}}; // { dg-error "no match" }
21 structured_rna<rna4> t3{rna4{}}; // { dg-bogus "no match" }
22