Issues with the new serde_derive system

[neon64]

When using that plugin, there are two errors:

error: the semantics of constant patterns is not yet settled (see issue #31434)
  --> src/state.rs:10:1
   |
10 | pub enum ArchiveEntryPerReplica {
   | ^
   |
   = help: add #![feature(structural_match)] to the crate attributes to enable

error: internal implementation detail (see issue #29642)
  --> src/state.rs:10:1
   |
10 | pub enum ArchiveEntryPerReplica {
   | ^
   |
   = help: add #![feature(rustc_attrs)] to the crate attributes to enable

Both of these are easily solvable by following the compiler's instructions. But I suppose my question is, why are these needed in the first place and should it be documented so that new users don't get tripped up?

Additionally if I run cargo doc then cargo tries to document the serde_derive crate and complains because it contains items with #[rustc_macro_derive].

error: the `#[rustc_macro_derive]` attribute is only usable with crates of the `rustc-macro` crate type
 --> /home/chris/.cargo/registry/src/github.jparrowsec.cn-1ecc6299db9ec823/serde_derive-0.8.10/src/lib.rs:9:3
  |
9 | #[rustc_macro_derive(Serialize)]
  |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: the `#[rustc_macro_derive]` attribute is only usable with crates of the `rustc-macro` crate type
  --> /home/chris/.cargo/registry/src/github.jparrowsec.cn-1ecc6299db9ec823/serde_derive-0.8.10/src/lib.rs:18:3
   |
18 | #[rustc_macro_derive(Deserialize)]
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I realise it is super early days for serde_derive but I thought I'd just point out these issues as from some quick searching I can't see any acknowledgement of them.

[dtolnay]

Thanks for reporting these!

The first one is fixed in rust-lang/rust#36782 and will be in tomorrow's nightly.

The second one I filed as rust-lang/cargo#3132.

[dtolnay]

I confirmed that #![feature(structural_match, rustc_attrs)] are no longer necessary in rustc 1.14.0-nightly (289f3a4ca 2016-09-29).

The doc issue is in progress at rust-lang/rust#36847.

[neon64]

Thanks very much by the way for the quick progress made on these two issues.

[dtolnay]

The rustdoc fix just merged. I will leave this ticket open until I can confirm that it works.

[dtolnay]

I confirmed that cargo doc works using rustc 1.14.0-nightly (9c31d76e9 2016-10-03).