[Bug c++/82531] New: ICE: Segmentation fault (-std=c++1z -fconcepts)

["gcc-bugs at deta dot lv" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82531

            Bug ID: 82531
           Summary: ICE: Segmentation fault (-std=c++1z -fconcepts)
           Product: gcc
           Version: 7.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gcc-bugs at deta dot lv
  Target Milestone: ---

Got ICE while experimenting with concepts.
The code is definitely no longer valid after passing through creduce, but ICE
is the same.
====
g++ -v
----
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/local-gcc-7.2/bin/../libexec/gcc/x86_64-pc-linux-gnu/7.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure --enable-languages=c,c++,lto --enable-multilib
Thread model: posix
gcc version 7.2.0 (GCC) 
====
command:
----
g++ -std=c++1z -fconcepts -c testcase.cpp
====
compiler output:
----
testcase.cpp: In instantiation of ‘auto operator-(auto:2, auto:2) [with auto:2
= tuple<>]’:
testcase.cpp:16:13:   required from here
testcase.cpp:12:47: internal compiler error: Segmentation fault
 auto operator-(tuple_type, tuple_type u) { map(u); }
                                            ~~~^~~
0xb127af crash_signal
        ../../gcc/toplev.c:337
0x613e10 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/cp/pt.c:13561
0x61e4b2 tsubst_template_args
        ../../gcc/cp/pt.c:11779
0x62714c tsubst_aggr_type
        ../../gcc/cp/pt.c:11981
0x614438 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/cp/pt.c:13487
0x6254e6 tsubst_qualified_id
        ../../gcc/cp/pt.c:14373
0x61f279 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/cp/pt.c:16962
0x618b37 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc/cp/pt.c:16550
0x71bbea satisfy_predicate_constraint
        ../../gcc/cp/constraint.cc:2016
0x71bbea satisfy_constraint_1
        ../../gcc/cp/constraint.cc:2244
0x71be44 satisfy_check_constraint
        ../../gcc/cp/constraint.cc:2061
0x71be44 satisfy_constraint_1
        ../../gcc/cp/constraint.cc:2247
0x71c1d0 satisfy_constraint
        ../../gcc/cp/constraint.cc:2302
0x71c2c3 satisfy_associated_constraints
        ../../gcc/cp/constraint.cc:2326
0x71c3c3 constraints_satisfied_p(tree_node*)
        ../../gcc/cp/constraint.cc:2401
0x5de5b9 add_function_candidate
        ../../gcc/cp/call.c:2072
0x5df0d9 add_template_candidate_real
        ../../gcc/cp/call.c:3208
0x5d6844 add_template_candidate
        ../../gcc/cp/call.c:3252
0x5d6844 add_candidates
        ../../gcc/cp/call.c:5483
0x5e0cc1 perform_overload_resolution
        ../../gcc/cp/call.c:4143
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.
====
reduced test case (testcase.cpp)
----
typedef int size_t;
template <typename _Tp, _Tp __v> struct integral_constant {
        static constexpr _Tp value = __v;
};

typedef integral_constant<bool, true> true_type;
template <typename...> class tuple {};

template <typename> struct is_tuple : true_type {};
template <class T> concept bool tuple_type = is_tuple<T>::value;
template <typename FUN> decltype() map(FUN, tuple_type... tuples);
auto operator-(tuple_type, tuple_type u) { map(u); }

using quantity = tuple<>;
constexpr quantity foo(quantity const& L, quantity const& R){
        return R - L;
}
====
I hope this helps.