Auto merge of #62507 - petrochenkov:macunstab, r=alexcrichton

Remove derives `Encodable`/`Decodable` and unstabilize attribute `#[bench]`

`Encodable` and `Decodable` were deprecated before 1.0 and emitted an unsuppressable warning all this time.
`#[bench]` is a part of the custom test framework feature and cannot be used meaningfully on stable, only as `cfg(false)`.

Crater results can be found in #62507 (comment) and below.

This PR also reroutes the tracking issue for `feature(test)` from #27812 (compiler internals) to #50297 (custom test frameworks).

Closes #62048

Author: bors

Diff for: src/libcore/hint.rs

@@ -110,7 +110,7 @@ pub fn spin_loop() {
 ///
 /// This function is a no-op, and does not even read from `dummy`.
 #[inline]
-#[unstable(feature = "test", issue = "27812")]
+#[unstable(feature = "test", issue = "50297")]
 #[allow(unreachable_code)] // this makes #[cfg] a bit easier below.
 pub fn black_box<T>(dummy: T) -> T {
     // We need to "use" the argument in some way LLVM can't introspect, and on

Diff for: src/libcore/macros.rs

@@ -1267,7 +1267,8 @@ pub(crate) mod builtin {
     pub macro test($item:item) { /* compiler built-in */ }
 
     /// Attribute macro applied to a function to turn it into a benchmark test.
-    #[stable(feature = "rust1", since = "1.0.0")]
+    #[unstable(feature = "test", issue = "50297",
+               reason = "`bench` is a part of custom test frameworks which are unstable")]
     #[allow_internal_unstable(test, rustc_attrs)]
     #[rustc_builtin_macro]
     #[rustc_macro_transparency = "semitransparent"]
@@ -1309,37 +1310,13 @@ pub(crate) mod builtin {
     #[allow_internal_unstable(core_intrinsics)]
     pub macro Debug($item:item) { /* compiler built-in */ }
 
-    /// Unstable implementation detail of the `rustc` compiler, do not use.
-    #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_deprecated(
-        since = "1.0.0",
-        reason = "derive(Decodable) is deprecated in favor of derive(RustcDecodable)",
-        suggestion = "RustcDecodable",
-    )]
-    #[allow_internal_unstable(core_intrinsics, libstd_sys_internals)]
-    pub macro Decodable($item:item) { /* compiler built-in */ }
-
     /// Derive macro generating an impl of the trait `Default`.
     #[rustc_builtin_macro]
     #[rustc_macro_transparency = "semitransparent"]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow_internal_unstable(core_intrinsics)]
     pub macro Default($item:item) { /* compiler built-in */ }
 
-    /// Unstable implementation detail of the `rustc` compiler, do not use.
-    #[rustc_builtin_macro]
-    #[rustc_macro_transparency = "semitransparent"]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    #[rustc_deprecated(
-        since = "1.0.0",
-        reason = "derive(Encodable) is deprecated in favor of derive(RustcEncodable)",
-        suggestion = "RustcEncodable",
-    )]
-    #[allow_internal_unstable(core_intrinsics)]
-    pub macro Encodable($item:item) { /* compiler built-in */ }
-
     /// Derive macro generating an impl of the trait `Eq`.
     #[rustc_builtin_macro]
     #[rustc_macro_transparency = "semitransparent"]

Diff for: src/libcore/prelude/v1.rs

@@ -54,9 +54,7 @@ pub use crate::macros::builtin::{
     Clone,
     Copy,
     Debug,
-    Decodable,
     Default,
-    Encodable,
     Eq,
     Hash,
     Ord,

Diff for: src/librustc_data_structures/lib.rs

@@ -22,9 +22,9 @@
 #![feature(stmt_expr_attributes)]
 #![feature(core_intrinsics)]
 #![feature(integer_atomics)]
+#![feature(test)]
 
 #![cfg_attr(unix, feature(libc))]
-#![cfg_attr(test, feature(test))]
 
 #![cfg_attr(not(bootstrap), allow(rustc::default_hash_types))]
 

Diff for: src/libstd/lib.rs

@@ -218,7 +218,7 @@
 // std may use features in a platform-specific way
 #![allow(unused_features)]
 
-#![cfg_attr(test, feature(print_internals, set_stdio, test, update_panic_count))]
+#![cfg_attr(test, feature(print_internals, set_stdio, update_panic_count))]
 #![cfg_attr(all(target_vendor = "fortanix", target_env = "sgx"),
             feature(slice_index_methods, decl_macro, coerce_unsized,
                     sgx_platform, ptr_wrapping_offset_from))]
@@ -304,6 +304,7 @@
 #![feature(stdsimd)]
 #![feature(stmt_expr_attributes)]
 #![feature(str_internals)]
+#![feature(test)]
 #![feature(thread_local)]
 #![feature(todo_macro)]
 #![feature(toowned_clone_into)]

Diff for: src/libstd/prelude/v1.rs

@@ -91,9 +91,7 @@ pub use core::prelude::v1::{
     Clone,
     Copy,
     Debug,
-    Decodable,
     Default,
-    Encodable,
     Eq,
     Hash,
     Ord,

Diff for: src/libsyntax_ext/deriving/decodable.rs

@@ -17,23 +17,7 @@ pub fn expand_deriving_rustc_decodable(cx: &mut ExtCtxt<'_>,
                                        mitem: &MetaItem,
                                        item: &Annotatable,
                                        push: &mut dyn FnMut(Annotatable)) {
-    expand_deriving_decodable_imp(cx, span, mitem, item, push, "rustc_serialize")
-}
-
-pub fn expand_deriving_decodable(cx: &mut ExtCtxt<'_>,
-                                 span: Span,
-                                 mitem: &MetaItem,
-                                 item: &Annotatable,
-                                 push: &mut dyn FnMut(Annotatable)) {
-    expand_deriving_decodable_imp(cx, span, mitem, item, push, "serialize")
-}
-
-fn expand_deriving_decodable_imp(cx: &mut ExtCtxt<'_>,
-                                 span: Span,
-                                 mitem: &MetaItem,
-                                 item: &Annotatable,
-                                 push: &mut dyn FnMut(Annotatable),
-                                 krate: &'static str) {
+    let krate = "rustc_serialize";
     let typaram = &*deriving::hygienic_type_parameter(item, "__D");
 
     let trait_def = TraitDef {

Diff for: src/libsyntax_ext/deriving/encodable.rs

@@ -98,23 +98,7 @@ pub fn expand_deriving_rustc_encodable(cx: &mut ExtCtxt<'_>,
                                        mitem: &MetaItem,
                                        item: &Annotatable,
                                        push: &mut dyn FnMut(Annotatable)) {
-    expand_deriving_encodable_imp(cx, span, mitem, item, push, "rustc_serialize")
-}
-
-pub fn expand_deriving_encodable(cx: &mut ExtCtxt<'_>,
-                                 span: Span,
-                                 mitem: &MetaItem,
-                                 item: &Annotatable,
-                                 push: &mut dyn FnMut(Annotatable)) {
-    expand_deriving_encodable_imp(cx, span, mitem, item, push, "serialize")
-}
-
-fn expand_deriving_encodable_imp(cx: &mut ExtCtxt<'_>,
-                                 span: Span,
-                                 mitem: &MetaItem,
-                                 item: &Annotatable,
-                                 push: &mut dyn FnMut(Annotatable),
-                                 krate: &'static str) {
+    let krate = "rustc_serialize";
     let typaram = &*deriving::hygienic_type_parameter(item, "__S");
 
     let trait_def = TraitDef {

Diff for: src/libsyntax_ext/lib.rs

@@ -92,9 +92,7 @@ pub fn register_builtin_macros(resolver: &mut dyn syntax::ext::base::Resolver, e
         Clone: clone::expand_deriving_clone,
         Copy: bounds::expand_deriving_copy,
         Debug: debug::expand_deriving_debug,
-        Decodable: decodable::expand_deriving_decodable,
         Default: default::expand_deriving_default,
-        Encodable: encodable::expand_deriving_encodable,
         Eq: eq::expand_deriving_eq,
         Hash: hash::expand_deriving_hash,
         Ord: ord::expand_deriving_ord,

Diff for: src/libtest/lib.rs

@@ -18,7 +18,7 @@
 // cargo) to detect this crate.
 
 #![crate_name = "test"]
-#![unstable(feature = "test", issue = "27812")]
+#![unstable(feature = "test", issue = "50297")]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/", test(attr(deny(warnings))))]
 #![feature(asm)]
 #![cfg_attr(any(unix, target_os = "cloudabi"), feature(libc, rustc_private))]

Diff for: src/test/run-make-fulldeps/pretty-expanded/input.rs

@@ -2,11 +2,11 @@
 
 // #13544
 
-extern crate serialize;
+extern crate serialize as rustc_serialize;
 
-#[derive(Encodable)] pub struct A;
-#[derive(Encodable)] pub struct B(isize);
-#[derive(Encodable)] pub struct C { x: isize }
-#[derive(Encodable)] pub enum D {}
-#[derive(Encodable)] pub enum E { y }
-#[derive(Encodable)] pub enum F { z(isize) }
+#[derive(RustcEncodable)] pub struct A;
+#[derive(RustcEncodable)] pub struct B(isize);
+#[derive(RustcEncodable)] pub struct C { x: isize }
+#[derive(RustcEncodable)] pub enum D {}
+#[derive(RustcEncodable)] pub enum E { y }
+#[derive(RustcEncodable)] pub enum F { z(isize) }

Diff for: src/test/run-make-fulldeps/save-analysis/foo.rs

@@ -418,8 +418,9 @@ impl Error + 'static + Send {
         <Error + 'static>::is::<T>(self)
     }
 }
-extern crate serialize;
-#[derive(Clone, Copy, Hash, Encodable, Decodable, PartialEq, Eq, PartialOrd, Ord, Debug, Default)]
+extern crate serialize as rustc_serialize;
+#[derive(Clone, Copy, Hash, RustcEncodable, RustcDecodable,
+         PartialEq, Eq, PartialOrd, Ord, Debug, Default)]
 struct AllDerives(i32);
 
 fn test_format_args() {

Diff for: src/test/ui-fulldeps/deprecated-derive.rs

@@ -32,6 +32,7 @@
 
 // check-pass
 
+#![feature(test)]
 #![warn(unused_attributes, unknown_lints)]
 
 // UNGATED WHITE-LISTED BUILT-IN ATTRIBUTES