Tracking issue for `custom_derive` feature

[aturon]

Treats #[derive(Anything)] like #[derive_Anything]. Tracking for stabilization.

[eefriedman]

There isn't really much incentive to stabilize this at the moment; this is basically only useful with plugins (and syntex, but the gate doesn't affect that usage).

[nrc]

Is there an RFC for this? I couldn't find one easily.

[eefriedman]

No RFC; see #23137.

[nrc]

Do we know who uses custom_derive? It seems like a horrible hack.

(Thanks for the link @eefriedman)

[pnkfelix]

wow look at the turnaround time on that PR! Proposed, r+'ed, and landed all in one day!

[jimmycuadra]

Two crates that use custom_derive: serde_macros and diesel_codegen.

[eefriedman]

Servo also uses it in a few places, for example https://github.com/servo/heapsize .

[nrc]

Thanks for the info. I think custom derive is something we should support, but not in the current form. I'll have a think about how it fits in to the procedural macro overhaul and write some kind of RFC.

[e-oz]

HOPE WILL NEVER DIE!

Can't use XML/JSON deserialization to structures, but I still hope...

😢