I can't remember if we've noticed this before, but it might need investigation:

clang-tidy-9 -p=/home/murrayc/checkout/github/libsigcplusplus/cmake_build /home/murrayc/checkout/github/libsigcplusplus/tests/test_limit_reference.cc
/home/murrayc/checkout/github/libsigcplusplus/sigc++/limit_reference.h:113:35: warning: Use of memory after it is freed [clang-analyzer-cplusplus.NewDelete]
inline T_type& invoke() const { return invoked; }
^
/home/murrayc/checkout/github/libsigcplusplus/tests/test_limit_reference.cc:37:7: note: Assuming the condition is false
if (!util->check_command_args(argc, argv))
^
/home/murrayc/checkout/github/libsigcplusplus/tests/test_limit_reference.cc:37:3: note: Taking false branch
if (!util->check_command_args(argc, argv))
^
/home/murrayc/checkout/github/libsigcplusplus/tests/test_limit_reference.cc:40:19: note: Memory is allocated
auto instance = new Derived();
^
/home/murrayc/checkout/github/libsigcplusplus/tests/test_limit_reference.cc:53:3: note: Memory is released
delete instance;
^
/home/murrayc/checkout/github/libsigcplusplus/tests/test_limit_reference.cc:56:3: note: Calling 'bind_functor::operator()'
param();
^
/home/murrayc/checkout/github/libsigcplusplus/sigc++/adaptors/bind.h:190:26: note: Calling 'tuple_transform_each<internal::TransformEachInvoker, std::tuple<sigc::bound_argument<std::reference_wrapper<(anonymous namespace)::Derived> > > &>'
const auto t_bound = internal::tuple_transform_eachinternal::TransformEachInvoker(bound_);
^
/home/murrayc/checkout/github/libsigcplusplus/sigc++/tuple-utils/tuple_transform_each.h:103:10: note: Calling 'tuple_transform_each_impl::tuple_transform_each'
return detail::tuple_transform_each_impl<T_transformer, size>::tuple_transform_each(
^
/home/murrayc/checkout/github/libsigcplusplus/sigc++/tuple-utils/tuple_transform_each.h:39:19: note: 1 is not equal to 0
if constexpr (size_from_index == 0)
^
/home/murrayc/checkout/github/libsigcplusplus/sigc++/tuple-utils/tuple_transform_each.h:39:5: note: Taking false branch
if constexpr (size_from_index == 0)
^
/home/murrayc/checkout/github/libsigcplusplus/sigc++/tuple-utils/tuple_transform_each.h:63:9: note: Calling 'TransformEachInvoker::transform'
T_transformer<from_element_type>::transform(std::get(t_original)));
^
/home/murrayc/checkout/github/libsigcplusplus/sigc++/adaptors/bind.h:110:74: note: Calling 'bound_argument::invoke'
constexpr static decltype(auto) transform(T_element& element) { return element.invoke(); }
^
/home/murrayc/checkout/github/libsigcplusplus/sigc++/adaptors/bound_argument.h:96:39: note: Calling 'limit_reference::invoke'
inline T_wrapped& invoke() { return visited_.invoke(); }
^
/home/murrayc/checkout/github/libsigcplusplus/sigc++/limit_reference.h:113:35: note: Use of memory after it is freed
inline T_type& invoke() const { return invoked; }