[klutzy]

This patchset makes warning if crate-level attribute is used at other places, obsolete attributed is used, or unknown attribute is used, since they are usually from mistakes.

Closes #3348

[alexcrichton]

This may also want to include

• no_implicit_prelude
• license

[klutzy]

no_implicit_prelude can be used on items:

#[no_implicit_prelude]
mod x {
  fn f() -> Option<int> { None } // error: use of undeclared type name `Option`
}

I initially included license, copyright and comment but I've found we don't use them at all, so I don't know how good including them is.

[alexcrichton]

They're not explicitly used anywhere currently, but all crate attributes contribute to the crate hash currently (but that may not stick around very long).

[alexcrichton]

It's probably fine to leave them out for now.

[emberian]

@klutzy any progress on this?

[klutzy]

I've completely forgot this! I've implemented unknown-attr lint but haven't added tests yet. It also needs update to reflect current attributes.

[klutzy]

I think it's done. r?

[emberian]

@klutzy needs rebase

[klutzy]

rebase done.
It may be worth to note that unknown-attr lint can be improved later (I'm not going to do it now): it might be good if it makes warning for #[deriving(Eq)] on function or #[packed]; on crate.