warning can longjmp when condition handlers are on the stack, causing leaks #1474

R -d "valgrind --tool=memcheck --leak-check=full --track-origins=yes" \
	-e "Rcpp::cppFunction('Rcpp::DataFrame test(SEXP a, SEXP b) { \
	      Rcpp::DataFrame DF; \
	      DF.push_back(a);    \
	      DF.push_back(b);    \
	      return DF; }');     \
            tryCatch( test(1:4, 11:15), warning = function(w) {} )"

==307332== 78 bytes in 1 blocks are definitely lost in loss record 37 of 1,605
==307332==    at 0x48859FC: operator new(unsigned long) (in /usr/libexec/valgrind/vgpreload_memcheck-arm64-linux.so)
==307332==    by 0x8923B7B: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_mutate(unsigned long, unsigned long, char const*, unsigned long) (in /usr/lib/aarch64-linux-gnu/libstdc++.so.6.0.33)
==307332==    by 0x8924ED3: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::_M_replace(unsigned long, unsigned long, char const*, unsigned long) (in /usr/lib/aarch64-linux-gnu/libstdc++.so.6.0.33)
==307332==    by 0x2462C4AF: replace (basic_string.h:2208)
==307332==    by 0x2462C4AF: replace (basic_string.h:2405)
==307332==    by 0x2462C4AF: assign<char*> (basic_string.h:1719)
==307332==    by 0x2462C4AF: str (sstream:253)
==307332==    by 0x2462C4AF: str (sstream:931)
==307332==    by 0x2462C4AF: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > tinyformat::format<>(char const*) (tinyformat.h:976)
==307332==    by 0x2462C88F: warning<> (exceptions.h:189)
==307332==    by 0x2462C88F: Rcpp::DataFrame_Impl<Rcpp::PreserveStorage>::set_type_after_push() (DataFrame.h:142)
==307332==    by 0x24625CFB: push_back<SEXPREC*> (DataFrame.h:77)
==307332==    by 0x24625CFB: test(SEXPREC*, SEXPREC*) (file4b0845e6c9e5c.cpp:6)
==307332==    by 0x24625F23: sourceCpp_1_test (file4b0845e6c9e5c.cpp:23)
==307332==    by 0x49C0167: ??? (in /usr/lib/R/lib/libR.so)
==307332==    by 0x49C0733: ??? (in /usr/lib/R/lib/libR.so)
==307332==    by 0x4A18C0B: Rf_eval (in /usr/lib/R/lib/libR.so)
==307332==    by 0x4A1A96B: ??? (in /usr/lib/R/lib/libR.so)
==307332==    by 0x4A1B7D3: Rf_applyClosure (in /usr/lib/R/lib/libR.so)