mbe: Fix feature gate for macro_derive

Author: joshtriplett

compiler/rustc_expand/src/mbe/macro_rules.rs

@@ -702,7 +702,7 @@ pub fn compile_declarative_macro(
             kinds |= MacroKinds::DERIVE;
             let derive_keyword_span = p.prev_token.span;
             if !features.macro_derive() {
-                feature_err(sess, sym::macro_attr, span, "`macro_rules!` derives are unstable")
+                feature_err(sess, sym::macro_derive, span, "`macro_rules!` derives are unstable")
                     .emit();
             }
             if let Some(guar) = check_no_eof(sess, &p, "expected `()` after `derive`") {

tests/ui/feature-gates/feature-gate-macro-derive.stderr

@@ -4,8 +4,8 @@ error[E0658]: `macro_rules!` derives are unstable
 LL | macro_rules! MyDerive { derive() {} => {} }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: see issue #83527 <https://github.com/rust-lang/rust/issues/83527> for more information
-   = help: add `#![feature(macro_attr)]` to the crate attributes to enable
+   = note: see issue #143549 <https://github.com/rust-lang/rust/issues/143549> for more information
+   = help: add `#![feature(macro_derive)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error: aborting due to 1 previous error