rust/src/test/ui/proc-macro/no-macro-use-attr.rs

// aux-build:derive-a.rs

#![feature(rustc_attrs)]
#![warn(unused_extern_crates)]

extern crate derive_a;
//~^ WARN unused extern crate

#[rustc_error]
fn main() {} //~ ERROR compilation successful
rustc: Implement custom derive (macros 1.1) This commit is an implementation of [RFC 1681] which adds support to the compiler for first-class user-define custom `#[derive]` modes with a far more stable API than plugins have today. [RFC 1681]: https://github.com/rust-lang/rfcs/blob/master/text/1681-macros-1.1.md The main features added by this commit are: * A new `rustc-macro` crate-type. This crate type represents one which will provide custom `derive` implementations and perhaps eventually flower into the implementation of macros 2.0 as well. * A new `rustc_macro` crate in the standard distribution. This crate will provide the runtime interface between macro crates and the compiler. The API here is particularly conservative right now but has quite a bit of room to expand into any manner of APIs required by macro authors. * The ability to load new derive modes through the `#[macro_use]` annotations on other crates. All support added here is gated behind the `rustc_macro` feature gate, both for the library support (the `rustc_macro` crate) as well as the language features. There are a few minor differences from the implementation outlined in the RFC, such as the `rustc_macro` crate being available as a dylib and all symbols are `dlsym`'d directly instead of having a shim compiled. These should only affect the implementation, however, not the public interface. This commit also ended up touching a lot of code related to `#[derive]`, making a few notable changes: * Recognized derive attributes are no longer desugared to `derive_Foo`. Wasn't sure how to keep this behavior and not expose it to custom derive. * Derive attributes no longer have access to unstable features by default, they have to opt in on a granular level. * The `derive(Copy,Clone)` optimization is now done through another "obscure attribute" which is just intended to ferry along in the compiler that such an optimization is possible. The `derive(PartialEq,Eq)` optimization was also updated to do something similar. --- One part of this PR which needs to be improved before stabilizing are the errors and exact interfaces here. The error messages are relatively poor quality and there are surprising spects of this such as `#[derive(PartialEq, Eq, MyTrait)]` not working by default. The custom attributes added by the compiler end up becoming unstable again when going through a custom impl. Hopefully though this is enough to start allowing experimentation on crates.io! syntax-[breaking-change] 2016-08-23 00:07:11 +00:00			`// aux-build:derive-a.rs`
rustdoc: Replace no-pretty-expanded with pretty-expanded Now that features must be declared expanded source often does not compile. This adds 'pretty-expanded' to a bunch of test cases that still work. 2015-03-22 20:13:15 +00:00
Support `#[macro_reexport]`ing custom derives. 2016-11-05 20:30:40 +00:00			`#![feature(rustc_attrs)]`
Stabilize `use_extern_macros` 2018-05-14 00:22:52 +00:00			`#![warn(unused_extern_crates)]`
Support `#[macro_reexport]`ing custom derives. 2016-11-05 20:30:40 +00:00
rustc: Implement custom derive (macros 1.1) This commit is an implementation of [RFC 1681] which adds support to the compiler for first-class user-define custom `#[derive]` modes with a far more stable API than plugins have today. [RFC 1681]: https://github.com/rust-lang/rfcs/blob/master/text/1681-macros-1.1.md The main features added by this commit are: * A new `rustc-macro` crate-type. This crate type represents one which will provide custom `derive` implementations and perhaps eventually flower into the implementation of macros 2.0 as well. * A new `rustc_macro` crate in the standard distribution. This crate will provide the runtime interface between macro crates and the compiler. The API here is particularly conservative right now but has quite a bit of room to expand into any manner of APIs required by macro authors. * The ability to load new derive modes through the `#[macro_use]` annotations on other crates. All support added here is gated behind the `rustc_macro` feature gate, both for the library support (the `rustc_macro` crate) as well as the language features. There are a few minor differences from the implementation outlined in the RFC, such as the `rustc_macro` crate being available as a dylib and all symbols are `dlsym`'d directly instead of having a shim compiled. These should only affect the implementation, however, not the public interface. This commit also ended up touching a lot of code related to `#[derive]`, making a few notable changes: * Recognized derive attributes are no longer desugared to `derive_Foo`. Wasn't sure how to keep this behavior and not expose it to custom derive. * Derive attributes no longer have access to unstable features by default, they have to opt in on a granular level. * The `derive(Copy,Clone)` optimization is now done through another "obscure attribute" which is just intended to ferry along in the compiler that such an optimization is possible. The `derive(PartialEq,Eq)` optimization was also updated to do something similar. --- One part of this PR which needs to be improved before stabilizing are the errors and exact interfaces here. The error messages are relatively poor quality and there are surprising spects of this such as `#[derive(PartialEq, Eq, MyTrait)]` not working by default. The custom attributes added by the compiler end up becoming unstable again when going through a custom impl. Hopefully though this is enough to start allowing experimentation on crates.io! syntax-[breaking-change] 2016-08-23 00:07:11 +00:00			`extern crate derive_a;`
Stabilize `use_extern_macros` 2018-05-14 00:22:52 +00:00			`//~^ WARN unused extern crate`
Make #[derive(Anything)] into sugar for #[derive_Anything] This is a hack, but I don't think we can do much better as long as `derive` is running at the syntax expansion phase. If the custom_derive feature gate is enabled, this works with user-defined traits and syntax extensions. Without the gate, you can't use e.g. #[derive_Clone] directly, so this does not change the stable language. This commit also cleans up the deriving code somewhat, and forbids some previously-meaningless attribute syntax. For this reason it's technically a [breaking-change] 2015-03-06 21:15:54 +00:00
Support `#[macro_reexport]`ing custom derives. 2016-11-05 20:30:40 +00:00			`#[rustc_error]`
			`fn main() {} //~ ERROR compilation successful`