[Bug c++/67131] New: [6 Regression] ICE: Segmentation fault

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67131

            Bug ID: 67131
           Summary: [6 Regression] ICE: Segmentation fault
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org
                CC: jason at gcc dot gnu.org
  Target Milestone: ---

trippels@gcc2-power8 test % cat metafunction.ii
template <typename T> typename T::_ type;
template <template <typename...> class> struct A;
template <template <typename> class f> A<f> metafunction;
namespace detail {
template <typename> struct _decltype;
}
template <template <typename...> class F> struct A {
  template <typename... T>
  auto operator()() -> decltype(type<F<detail::_decltype<T>...>>);
};
template <typename F> auto valid_call(F f) -> decltype(f());
constexpr auto valid_call(...) { return 0; }
template <typename> struct no_type;
static_assert(!valid_call(metafunction<no_type>),"");

trippels@gcc2-power8 test % clang++ -Wall -Wextra -c -std=c++14 metafunction.ii
trippels@gcc2-power8 test % g++ -c metafunction.ii
metafunction.ii: In substitution of ‘template<class ... T> decltype
(type<F<detail::_decltype<T>...> >) A< <template-parameter-1-1> >::operator()()
[with T = {}]’:
metafunction.ii:11:57:   required by substitution of ‘template<class F>
decltype (f()) valid_call(F) [with F = A<no_type>]’
metafunction.ii:14:48:   required from here
metafunction.ii:9:8: internal compiler error: Segmentation fault
   auto operator()() -> decltype(type<F<detail::_decltype<T>...>>);
        ^
0x10a19a33 crash_signal
        ../../gcc/gcc/toplev.c:352
0x1031435c invalid_nonstatic_memfn_p
        ../../gcc/gcc/cp/typeck.c:1815
0x10385f67 finish_decltype_type(tree_node*, bool, int)
        ../../gcc/gcc/cp/semantics.c:7172
0x1020c867 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:12686
0x1021219f tsubst_function_type
        ../../gcc/gcc/cp/pt.c:11749
0x1020c033 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:12493
0x1021911b tsubst_decl
        ../../gcc/gcc/cp/pt.c:10969
0x1020c3f3 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:11965
0x10209c4f instantiate_template_1
        ../../gcc/gcc/cp/pt.c:16156
0x10209c4f instantiate_template(tree_node*, tree_node*, int)
        ../../gcc/gcc/cp/pt.c:16207
0x10236c27 fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node*
const*, unsigned int, tree_node*, unification_kind_t, int, bool, bool)
        ../../gcc/gcc/cp/pt.c:16556
0x10188d3b add_template_candidate_real
        ../../gcc/gcc/cp/call.c:3022
0x1018996f add_template_candidate
        ../../gcc/gcc/cp/call.c:3119
0x1018996f add_candidates
        ../../gcc/gcc/cp/call.c:5245
0x1019012b build_op_call_1
        ../../gcc/gcc/cp/call.c:4232
0x1019012b build_op_call(tree_node*, vec<tree_node*, va_gc, vl_embed>**, int)
        ../../gcc/gcc/cp/call.c:4319
0x1037e2e3 finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**,
bool, bool, int)
        ../../gcc/gcc/cp/semantics.c:2408
0x10222d6b tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc/gcc/cp/pt.c:15397
0x1020b8e3 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:12666
0x10211ebb tsubst_function_type
        ../../gcc/gcc/cp/pt.c:11749
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