clang_error_tsv

./typesafevariant3.cpp:13:43: error: no member named 'bar' in 'type_safe::nullvar_t'
    auto operator()(T x) const { return x.bar(); }
                                        ~ ^
/usr/local/include/type_safe/visitor.hpp:180:29: note: in instantiation of function template
      specialization 'visitor::operator()<type_safe::nullvar_t>' requested here
                -> decltype(std::forward<Visitor>(visitor)(std::forward<Args>(args)...))
                            ^
/usr/local/include/type_safe/visitor.hpp:194:29: note: while substituting deduced template arguments
      into function template 'call_impl' [with Args = <const type_safe::nullvar_t &>]
                -> decltype(call_impl(0, std::forward<Visitor>(visitor),
                            ^
/usr/local/include/type_safe/visitor.hpp:223:50: note: while substituting deduced template arguments
      into function template 'call' [with Args = <const type_safe::nullvar_t &>]
                                        decltype(visit_variant_impl<AllowIncomplete, Visitor>::call(
                                                 ^
/usr/local/include/type_safe/visitor.hpp:263:43: note: while substituting deduced template arguments
      into function template 'call_type' [with $0 = type_safe::detail::visit_variant_impl<false, visitor
      &, type_safe::basic_variant<type_safe::detail::non_empty_variant_policy<false>, a, b, c> &>, Args
      = <>, Variant2 = (no value)]
                                 decltype(RecursiveDecltype::template call_type<RecursiveDecltype>(
                                          ^
/usr/local/include/type_safe/visitor.hpp:263:43: note: while substituting deduced template arguments
      into function template 'call_type' [with RecursiveDecltype =
      type_safe::detail::visit_variant_impl<false, visitor &,
      type_safe::basic_variant<type_safe::detail::non_empty_variant_policy<false>, a, b, c> &>, Head =
      c, Tail = <>, Args = <>]
/usr/local/include/type_safe/visitor.hpp:263:43: note: while substituting deduced template arguments
      into function template 'call_type' [with RecursiveDecltype =
      type_safe::detail::visit_variant_impl<false, visitor &,
      type_safe::basic_variant<type_safe::detail::non_empty_variant_policy<false>, a, b, c> &>, Head =
      b, Tail = <c>, Args = <>]
/usr/local/include/type_safe/visitor.hpp:284:29: note: while substituting deduced template arguments
      into function template 'call_type' [with RecursiveDecltype =
      type_safe::detail::visit_variant_impl<false, visitor &,
      type_safe::basic_variant<type_safe::detail::non_empty_variant_policy<false>, a, b, c> &>, Head =
      a, Tail = <b, c>, Args = <>]
                -> decltype(call_type<visit_variant_impl>(
                            ^
/usr/local/include/type_safe/visitor.hpp:385:13: note: while substituting deduced template arguments
      into function template 'call' [with Args = <>]
            visit_variant_impl<visitor_allow_incomplete<Visitor>::value, Visitor&&,
            ^
/usr/local/include/type_safe/visitor.hpp:415:21: note: while substituting deduced template arguments
      into function template 'visit_variant' [with Visitor = visitor &, Variants =
      <type_safe::basic_variant<type_safe::detail::non_empty_variant_policy<false>, a, b, c> &>]
        -> decltype(detail::visit_variant(std::forward<Visitor>(visitor),
                    ^
./typesafevariant3.cpp:20:5: note: while substituting deduced template arguments into function template
      'visit' [with Visitor = visitor &, Variants =
      <type_safe::basic_variant<type_safe::detail::non_empty_variant_policy<false>, a, b, c> &>, $2 =
      (no value)]
    type_safe::visit(v, x);
    ^