https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107460
Bug ID: 107460
Summary: ICE with "using enum" member passed to template
function (g++ 11.x-13)
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: chris-gcc-bugzilla at cybermato dot com
Target Milestone: ---
Created attachment 53793
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53793&action=edit
file generated by -freport-bug
The following code (also attached) causes an ICE in tsubst_copy on every
version of g++ that can handle "using enum", with either -std=c++20 or
-std=gnu++20, regardless of -O0, -O1, -O2, etc.:
trunk (13.0.0 20221028) (Godbolt)
12.2.0 (Godbolt)
12.1.0 (Ubuntu 22.04)
11.3.0 (Godbolt)
11.2.0 (Ubuntu 22.04)
11.1 (Ubuntu 20.04)
(10.4 and earlier don't seem to support "using enum")
clang 13, 14, and 15 compile it with no complaint, as does MSVC (19.33 per
Godbolt, plus VS 2019 and VS 2022).
If I pass 'EventCat::kEventCat_Min' to boundsCheck() instead of just
'kEventCat_Min', it compiles without error.
---------------------------------------------------------------------------------
void fatal [[noreturn]] (const char * msg);
template <typename ToType, typename FromType, typename MinType>
ToType boundsCheck(const FromType & value, const MinType & min)
{
if (int(value) >= int(min))
{
return static_cast<ToType>(value);
}
fatal ("nope");
}
enum class EventCat
{
kEventCat_NeverUseThis = 0,
kUninitialized,
kTesting,
kEventCat_Min = kEventCat_NeverUseThis + 1,
};
struct Event
{
using enum EventCat;
Event(EventCat a_category, auto)
: category(a_category)
{
boundsCheck<EventCat>(a_category, kEventCat_Min); // using
"EventCat::kEventCat_Min" instead of just "kEventCat_Min" makes this not fail
}
EventCat category = EventCat::kUninitialized;
};
void foo()
{
Event(EventCat::kTesting, 0);
}
---------------------------------------------------------------------------------
On Ubuntu 22.04 using g++-12 (Ubuntu 12.1.0-2ubuntu1~22.04) 12.1.0:
$ g++-12 -c -std=c++20 g++-ice-in-tsubst_copy.cpp
g++-ice-in-tsubst_copy.cpp: In instantiation of ‘Event::Event(EventCat, auto:1)
[with auto:1 = int]’:
g++-ice-in-tsubst_copy.cpp:38:32: required from here
g++-ice-in-tsubst_copy.cpp:30:30: internal compiler error: in tsubst_copy, at
cp/pt.cc:16919
30 | boundsCheck<EventCat>(a_category, kEventCat_Min); // using
"EventCat::kEventCat_Min" instead of just "kEventCat_Min" makes this not fail
| ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
0x661b9b tsubst_copy
../../src/gcc/cp/pt.cc:16919
0x80f2ce tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
../../src/gcc/cp/pt.cc:21399
0x81e961 tsubst_copy_and_build_call_args
../../src/gcc/cp/pt.cc:19937
0x80f8c0 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
../../src/gcc/cp/pt.cc:20687
0x8200e8 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:19491
0x821097 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:18462
0x821097 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:18504
0x820c28 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:18462
0x820c28 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:18833
0x821632 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:18462
0x821632 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:18476
0x820c28 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:18462
0x820c28 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:18833
0x81f63c tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
../../src/gcc/cp/pt.cc:26412
0x81f63c instantiate_body
../../src/gcc/cp/pt.cc:26412
0x81ff09 instantiate_decl(tree_node*, bool, bool)
../../src/gcc/cp/pt.cc:26704
0x834bdb instantiate_pending_templates(int)
../../src/gcc/cp/pt.cc:26783
0x739197 c_parse_final_cleanups()
../../src/gcc/cp/decl2.cc:5128
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <file:///usr/share/doc/gcc-12/README.Bugs> for instructions.
