[GNATS 24681] Spurious diagnostic for expression must have a constant value

[jhsedg]

Customer bug ID

hof/test/function.cpp, gnats/24681.C

Description

​Here is the reduced test case:
​
​//type:fp
​//options_all:--c++20 --gnu_version 110100 -tused -w
​template struct seq;
​template struct basic_first_of_adaptor : F1 {};
​struct pack_tag;
​template <class...> struct pack_base;
​template <class, class, class X> constexpr int pack_get(X) { return 0; }
​template <unsigned long... Ns, class... Ts>
​struct pack_base<seq<Ns...>, Ts...> {
​ template constexpr auto operator()(F f) {
​ return f(pack_get<Ts, pack_tag>(this)...);
​ }
​};
​struct {
​ template <class... Ts>
​ constexpr auto operator()(Ts...) -> decltype(pack_base<seq<0>, Ts &&...>()) {
​ return pack_base<seq<0>, Ts &&...>();
​ }
​} pack_forward;
​template struct partial_adaptor;
​struct mono_class;
​template struct partial_adaptor_invoke {
​ constexpr F get_function() {
​ return static_cast<partial_adaptor<mono_class> &>(*this);
​ }
​ template <class... Ts> constexpr auto operator()(Ts...) {
​ auto __trans_tmp_1 = pack_forward(Ts()...);
​ pack_base __trans_tmp_4(__trans_tmp_1);
​ return __trans_tmp_4(get_function());
​ }
​};
​struct partial_adaptor_base {
​ typedef basic_first_of_adaptor<partial_adaptor_invoke<mono_class>> type;
​};
​template struct partial_adaptor : partial_adaptor_base::type, F {
​ partial_adaptor_base::type::operator();
​ template partial_adaptor(S);
​};
​struct mono_class {
​ constexpr int operator()(int) { return 1; }
​} mono_partial_constexpr;
​struct test_63 {
​ void operator()() const;
​};
​void test_63::operator()() const {
​ partial_adaptor<mono_class> __trans_tmp_6 = mono_partial_constexpr;
​ static_assert(__trans_tmp_6(2));
​}
​[ellen@lin1 modules]$ (nrt-mods)fgrep Temporary ms_mods.9.3 | wc -l
​fe_only -DTEST_NUMBER=1 --c++20 --gnu_version 110100 -tused -w Test_name.c
​"Test_name.c", line 47: error: expression must have a constant value
​ static_assert(__trans_tmp_6(2));
​ ^
​"Test_name.c", line 24: note: attempt to access run-time storage
​ return static_cast<partial_adaptor<mono_class> &>(*this);
​ ^
​"Test_name.c", line 29: note: called from:
​ return __trans_tmp_4(get_function());
​ ^
​
​1 error detected in the compilation of "Test_name.c".
​24680.C:fp::FAIL--NO PREVIOUS OUTPUT:

Notes

​2024-12-17, ellen:
​Boost 1.87.0 no longer has this test (the math portion was a major update)