serde_json fails when using flattening while tracing-bunyan-formatter in dependencies

[thekuom]

Minimal example: https://github.com/thekuom/serde_json_tracing_bunyan_formatter_bug_report

When calling serde_json::from_str() on a struct with #[serde(flatten)], I get the following error:

deserialize failed: Error("invalid type: map, expected i32", line: 3, column: 9)

Without tracing-bunyan-formatter installed, the deserialization succeeds, which you can check on the without-tracing-bunyan-formatter branch in my minimal example.

I also commented on an issue here: serde-rs/json#768 (comment)

[thekuom]

Actually, just found serde-rs/json#505, and tracing-bunyan-formatter has arbitrary-precision on by default