[Bug c++/68884] template of value template crashes the compiler

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68884

--- Comment #5 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
markus@x4 /tmp % cat tst.ii
namespace std {
template <typename _Tp, _Tp __v> struct A { static constexpr _Tp value = __v;
};
typedef A<bool, true> true_type;
}
template <int> struct VsA;
template <class ValueType> struct ValueTemplate {
  template <template <ValueType> class, class> struct IsInstanceOf;
  template <template <ValueType> class TemplateA, ValueType... TypesA>
  struct IsInstanceOf<TemplateA, TemplateA<TypesA...>> : std::true_type {};
};
bool foo = ValueTemplate<int>::IsInstanceOf<VsA, VsA<0>>::value;


markus@x4 /tmp % g++ -c tst.ii
tst.ii:11:57: internal compiler error: in tsubst, at cp/pt.c:12869
 bool foo = ValueTemplate<int>::IsInstanceOf<VsA, VsA<0>>::value;
                                                         ^~

0x64ff30 tsubst(tree_node*, tree_node*, int, tree_node*)
        ../../gcc/gcc/cp/pt.c:12869
0x6524b0 convert_template_argument
        ../../gcc/gcc/cp/pt.c:7194
0x65f379 coerce_template_parms
        ../../gcc/gcc/cp/pt.c:7684
0x66d267 unify
        ../../gcc/gcc/cp/pt.c:19378
0x66c88b unify
        ../../gcc/gcc/cp/pt.c:19709
0x66ebff get_partial_spec_bindings
        ../../gcc/gcc/cp/pt.c:20469
0x66687a most_specialized_partial_spec
        ../../gcc/gcc/cp/pt.c:20741
0x682153 instantiate_class_template_1
        ../../gcc/gcc/cp/pt.c:9698
0x682153 instantiate_class_template(tree_node*)
        ../../gcc/gcc/cp/pt.c:10259
0x72b43b complete_type(tree_node*)
        ../../gcc/gcc/cp/typeck.c:131
0x6f8b90 cp_parser_nested_name_specifier_opt
        ../../gcc/gcc/cp/parser.c:6027
0x71bcc9 cp_parser_simple_type_specifier
        ../../gcc/gcc/cp/parser.c:16120
0x6f7456 cp_parser_postfix_expression
        ../../gcc/gcc/cp/parser.c:6533
0x700ff4 cp_parser_unary_expression
        ../../gcc/gcc/cp/parser.c:7901
0x701c7b cp_parser_cast_expression
        ../../gcc/gcc/cp/parser.c:8578
0x702097 cp_parser_binary_expression
        ../../gcc/gcc/cp/parser.c:8679
0x702a74 cp_parser_assignment_expression
        ../../gcc/gcc/cp/parser.c:8966
0x70300a cp_parser_constant_expression
        ../../gcc/gcc/cp/parser.c:9236
0x7038f5 cp_parser_initializer_clause
        ../../gcc/gcc/cp/parser.c:20679
0x7057f5 cp_parser_initializer
        ../../gcc/gcc/cp/parser.c:20622