Auto merge of #54271 - petrochenkov:nolegder, r=eddyb,alexcrichton

Unsupport `#[derive(Trait)]` sugar for `#[derive_Trait]` legacy plugin attributes

This is a long deprecated unstable feature that doesn't mesh well with regular resolution/expansion.

How to fix broken code:
- The recommended way is to migrate to stable procedural macros - derives or attributes (https://doc.rust-lang.org/nightly/book/first-edition/procedural-macros.html).
- If that's not possible right now for some reason, you can keep code working with a simple mechanical replacement `#[derive(Legacy)]` -> `#[derive_Legacy]`.

Closes https://github.com/rust-lang/rust/issues/29644

r? @ghost

1 files changed, 3 insertions, 6 deletions

diff --git a/src/libsyntax_ext/lib.rs b/src/libsyntax_ext/lib.rs
index 1d814a67876..c49d5772531 100644
--- a/src/libsyntax_ext/lib.rs
+++ b/src/libsyntax_ext/lib.rs
@@ -39,10 +39,6 @@ extern crate log;
 
 mod diagnostics;
 
-#[macro_use]
-// for custom_derive
-pub mod deriving;
-
 mod asm;
 mod assert;
 mod cfg;
@@ -54,13 +50,14 @@ mod format;
 mod format_foreign;
 mod global_asm;
 mod log_syntax;
-mod trace_macros;
+mod proc_macro_server;
 mod test;
 mod test_case;
+mod trace_macros;
 
+pub mod deriving;
 pub mod proc_macro_decls;
 pub mod proc_macro_impl;
-mod proc_macro_server;
 
 use rustc_data_structures::sync::Lrc;
 use syntax::ast;