https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103313
Bug ID: 103313
Summary: nontype_argument_pack - compile error due to
unsupported tree
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ispavlick at gmail dot com
Target Milestone: ---
#include <array>
#include <tuple>
using namespace std;
struct Q {
void set(int i) {}
};
template <int I>
struct S {
Q mq[I];
template <size_t ...num>
void f(array<int, I> &a,
index_sequence<num...> n=make_index_sequence<I>{}) {
((mq[num].set(a[num])), ...);
}
};
int main() {
S<3> s;
array a{2, 5, 7};
s.f(a); // error
//s.f(a, make_index_sequence<3>{}); // ok
}
$ g++ 1.cpp -std=c++20
1.cpp: In member function ‘void S<I>::f(std::array<int, I>&,
std::index_sequence<num ...>) [with long unsigned int ...num = {}; int I = 3;
std::index_sequence<num ...> = std
::integer_sequence<long unsigned int>]’:
1.cpp:22:8: error: could not convert ‘std::make_index_sequence<3>{}’ from
‘integer_sequence<[...],‘nontype_argument_pack’ not supported by
dump_expr<expression error>>’ to
integer_sequence<[...],‘nontype_argument_pack’ not supported by
dump_expr<expression error>>’
22 | s.f(a);
| ~~~^~~
| |
| integer_sequence<[...],‘nontype_argument_pack’ not supported by
dump_expr<expression error>>
1.cpp:22:8: note: when instantiating default argument for call to ‘void
S<I>::f(std::array<int, I>&, std::index_sequence<num ...>) [with long unsigned
int ...num = {}; int
I = 3; std::index_sequence<num ...> = std::integer_sequence<long unsigned
int>]’
1.cpp: In function ‘int main()’:
1.cpp:22:8: error: could not convert ‘std::make_index_sequence<3>{}’ from
‘integer_sequence<[...],‘nontype_argument_pack’ not supported by
dump_expr<expression error>>’ to
integer_sequence<[...],‘nontype_argument_pack’ not supported by
dump_expr<expression error>>’
