This is also my error, and the author has been informed. He just hasn't updated the post yet, but will. I forgot that this got stabilized. It's easy to lose tr

This is also my error, and the author has been informed. He just hasn't updated the post yet, but will. I forgot that this got stabilized. It's easy to lose track of everything sometimes! EDIT: oops forgot to reply to this: > I'm not sure if it's because Serde started before it was allowed or if it's a stylistic preference or what. This was stabilized post 1.0, and serde is (as you know) older than Rust 1.0. That's why I thought that it wasn't possible. https://doc.rust-lang.org/1.0.0/reference.html#attributes https://doc.rust-lang.org/1.0.0/reference.html#attributes says > An identifier followed by the equals sign '=' and a literal, providing a key/value pair Of course, we didn't even have stable proc macros at that point. I tried to dig into the exact history here for a bit, but didn't manage to find the exact point at which this came to be, it was taking too long.