expand/resolve: Turn #[derive] into a regular macro attribute

Author: petrochenkov

core/src/macros/mod.rs

@@ -1324,6 +1324,14 @@ pub(crate) mod builtin {
         (false) => {{ /* compiler built-in */ }};
     }
 
+    /// Attribute macro used to apply derive macros.
+    #[cfg(not(bootstrap))]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_builtin_macro]
+    pub macro derive($item:item) {
+        /* compiler built-in */
+    }
+
     /// Attribute macro applied to a function to turn it into a unit test.
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(test, rustc_attrs)]

core/src/prelude/v1.rs

@@ -69,6 +69,11 @@ pub use crate::macros::builtin::{
     bench, global_allocator, test, test_case, RustcDecodable, RustcEncodable,
 };
 
+#[cfg(not(bootstrap))]
+#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
+#[doc(no_inline)]
+pub use crate::macros::builtin::derive;
+
 #[unstable(
     feature = "cfg_accessible",
     issue = "64797",

std/src/prelude/v1.rs

@@ -54,6 +54,11 @@ pub use core::prelude::v1::{
     bench, global_allocator, test, test_case, RustcDecodable, RustcEncodable,
 };
 
+#[cfg(not(bootstrap))]
+#[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
+#[doc(hidden)]
+pub use core::prelude::v1::derive;
+
 #[unstable(
     feature = "cfg_accessible",
     issue = "64797",