$ root.exe -b -l
root [0] struct Content { double d = std::numeric_limits<double>::infinity(); }
root [1] Content c;
root [2] auto s = TBufferJSON::ToJSON(&c)
(TString &) "{
  "_typename" : "Content",
  "d" : 2e308
}"[44]
root [3] Content *p = nullptr;
root [4] TBufferJSON::FromJSON<Content>(p, s)
libc++abi: terminating due to uncaught exception of type nlohmann::detail::out_of_range: [json.exception.out_of_range.406] number overflow parsing '2e308'
Abort trap: 6

root [0] struct Content { double d = std::numeric_limits<double>::infinity(); }
root [1] Content *p = nullptr;
root [2] TString s = "{ \"_typename\" : \"Content\", \"d\" : null }"
(TString &) "{ "_typename" : "Content", "d" : null }"[39]
root [3] TBufferJSON::FromJSON<Content>(p, s)
(bool) true
root [4] p->d
(double) nan