For those interested a link to an article published yesterday on the JSON specifications and the compliance of various parsers. Two of the implementations tested are in Rust, namely rustc_serialize::json and json-rust.
Here is the graph of serde_json results. The only thing we feel the need to address is stack overflow. Beyond that, the two other “failures” are UTF-16 which I am not interested in supporting and large exponents which I think is mistakenly in the “y” category when really it is implementation-defined.