https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100138
Bug ID: 100138
Summary: ICE with constructor constrained (C++20 Concepts) by
parameter pack length
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pkeir at outlook dot com
Target Milestone: ---
Created attachment 50624
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50624&action=edit
The C++ file producing the ICE
Compiling the code below with `-c -std=c++20` produces an ICE.
template <int N = 1>
struct Foo
{
template <typename ...Ts>
Foo(Ts... xs) requires(sizeof...(xs)==N) {}
};
void bar()
{
Foo x{64};
}
As a workaround, using Ts rather than xs within the requires clause avoids the
ICE. The error message is below:
constrained_ctor.hpp: In substitution of ‘template<int N, class ... Ts> Foo(Ts
...)-> Foo<N> requires sizeof ... ((Foo<N>::__ct ::xs ...)) == N [with int N =
1; Ts = {int}]’:
constrained_ctor.hpp:10:11: required from here
constrained_ctor.hpp:5:26: internal compiler error: Segmentation fault
5 | Foo(Ts... xs) requires(sizeof...(xs)==N) {}
| ^~~~~~~~~~~~~
0x10d0e8f crash_signal
../../gcc/toplev.c:327
0x950d49 hash_table<hash_map<tree_node*, tree_node*,
simple_hashmap_traits<default_hash_traits<tree_node*>, tree_node*>
>::hash_entry, false, xcallocator>::find_slot_with_hash(tree_node* const&,
unsigned int, insert_option)
../../gcc/hash-table.h:963
0xac055d hash_map<tree_node*, tree_node*,
simple_hashmap_traits<default_hash_traits<tree_node*>, tree_node*>
>::put(tree_node* const&, tree_node* const&)
../../gcc/hash-map.h:166
0xac055d register_local_specialization(tree_node*, tree_node*)
../../gcc/cp/pt.c:2004
0xad21e1 gen_elem_of_pack_expansion_instantiation
../../gcc/cp/pt.c:12496
0xad21e1 tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*)
../../gcc/cp/pt.c:13173
0xac63be tsubst_copy
../../gcc/cp/pt.c:16925
0xac7ca4 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
../../gcc/cp/pt.c:20896
0xac7ad3 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
../../gcc/cp/pt.c:19856
0xad3128 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../gcc/cp/pt.c:19144
0x95a455 satisfy_atom
../../gcc/cp/constraint.cc:2984
0x95a455 satisfy_constraint_r
../../gcc/cp/constraint.cc:3047
0x95a779 satisfy_normalized_constraints
../../gcc/cp/constraint.cc:3069
0x957d7e satisfy_declaration_constraints
../../gcc/cp/constraint.cc:3277
0x957d7e constraint_satisfaction_value
../../gcc/cp/constraint.cc:3297
0x95a810 constraints_satisfied_p(tree_node*, tree_node*)
../../gcc/cp/constraint.cc:3334
0xaf98a5 fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node*
const*, unsigned int, tree_node*, unification_kind_t, int, conversion**, bool,
bool)
../../gcc/cp/pt.c:21632
0x9053fd add_template_candidate_real
../../gcc/cp/call.c:3456
0x905eda add_template_candidate
../../gcc/cp/call.c:3541
0x905eda add_candidates
../../gcc/cp/call.c:6031
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
