https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121325
Bug ID: 121325 Summary: ICE on pack index in noexcept specifier of generic lambda in requires clause Product: gcc Version: 16.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: eczbek.void at gmail dot com Target Milestone: --- https://godbolt.org/z/rM5s13j3f void f(auto... a) requires requires { []<int i = 0> noexcept(noexcept(a...[i])) {}(); } {} int main() { f(0); } <source>: In instantiation of '<lambda()> [with int i = 0]': <source>:1:83: required by substitution of 'template<class ... auto:1> void f(auto:1 ...) requires requires{(<lambda>)();} [with auto:1 = {int}]' 1 | void f(auto... a) requires requires { []<int i = 0> noexcept(noexcept(a...[i])) {}(); } {} | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~ <source>:3:15: required from here 3 | int main() { f(0); } | ~^~~ <source>:1:39: internal compiler error: in tsubst_expr, at cp/pt.cc:22175 1 | void f(auto... a) requires requires { []<int i = 0> noexcept(noexcept(a...[i])) {}(); } {} | ^ 0x288a1c5 diagnostics::context::diagnostic_impl(rich_location*, diagnostics::metadata const*, diagnostics::option_id, char const*, __va_list_tag (*) [1], diagnostics::kind) ???:0 0x287fa76 internal_error(char const*, ...) ???:0 0xaf6192 fancy_abort(char const*, int, char const*) ???:0 0xd74619 tsubst_template_args(tree_node*, tree_node*, int, tree_node*) ???:0 0xd59067 tsubst(tree_node*, tree_node*, int, tree_node*) ???:0 0xd76f14 tsubst_pack_index(tree_node*, tree_node*, int, tree_node*) ???:0 0xd43e8b maybe_instantiate_noexcept(tree_node*, int) ???:0 0xc05b1a mark_used(tree_node*, int) ???:0 0xb32973 build_op_call(tree_node*, vec<tree_node*, va_gc, vl_embed>**, int) ???:0 0xda6d8e finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool, bool, int) ???:0 0xb848e6 tsubst_requires_expr(tree_node*, tree_node*, int, tree_node*) ???:0 0xb85d78 constraints_satisfied_p(tree_node*, tree_node*) ???:0 0xd84a71 fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node* const*, unsigned int, tree_node*, unification_kind_t, int, conversion**, bool, bool) ???:0 0xb2e069 build_new_function_call(tree_node*, vec<tree_node*, va_gc, vl_embed>**, int) ???:0 0xda69ac finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool, bool, int) ???:0 0xd24083 c_parse_file() ???:0 0xe8ec79 c_common_parse_file() ???:0 Please submit a full bug report, with preprocessed source (by using -freport-bug). Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions. Compiler returned: 1