Rollup merge of rust-lang#61660 - petrochenkov:nocusta, r=Centril

Minimize use of `#![feature(custom_attribute)]`

Some preparations before resurrecting rust-lang#57921.

Author: Centril

src/doc/rustc/src/lints/listing/warn-by-default.md

@@ -728,19 +728,17 @@ This lint detects attributes that were not used by the compiler. Some
 example code that triggers this lint:
 
 ```rust
-#![feature(custom_attribute)]
-
-#![mutable_doc]
+#![macro_export]
 ```
 
 This will produce:
 
 ```text
 warning: unused attribute
- --> src/main.rs:4:1
+ --> src/main.rs:1:1
   |
-4 | #![mutable_doc]
-  | ^^^^^^^^^^^^^^^
+1 | #![macro_export]
+  | ^^^^^^^^^^^^^^^^
   |
 ```
 

src/liballoc/alloc.rs

@@ -15,7 +15,8 @@ extern "Rust" {
     // them from the `#[global_allocator]` attribute if there is one, or uses the
     // default implementations in libstd (`__rdl_alloc` etc in `src/libstd/alloc.rs`)
     // otherwise.
-    #[allocator]
+    #[cfg_attr(bootstrap, allocator)]
+    #[cfg_attr(not(bootstrap), rustc_allocator)]
     #[rustc_allocator_nounwind]
     fn __rust_alloc(size: usize, align: usize) -> *mut u8;
     #[rustc_allocator_nounwind]

src/liballoc/lib.rs

@@ -79,7 +79,7 @@
 #![feature(coerce_unsized)]
 #![feature(dispatch_from_dyn)]
 #![feature(core_intrinsics)]
-#![feature(custom_attribute)]
+#![cfg_attr(bootstrap, feature(custom_attribute))]
 #![feature(dropck_eyepatch)]
 #![feature(exact_size_is_empty)]
 #![feature(fmt_internals)]

src/libcore/lib.rs

@@ -75,7 +75,6 @@
 #![feature(concat_idents)]
 #![feature(const_fn)]
 #![feature(const_fn_union)]
-#![feature(custom_attribute)]
 #![feature(doc_cfg)]
 #![feature(doc_spotlight)]
 #![feature(extern_types)]

src/librustc/hir/mod.rs

@@ -2574,7 +2574,7 @@ bitflags! {
         /// `#[cold]`: a hint to LLVM that this function, when called, is never on
         /// the hot path.
         const COLD                      = 1 << 0;
-        /// `#[allocator]`: a hint to LLVM that the pointer returned from this
+        /// `#[rustc_allocator]`: a hint to LLVM that the pointer returned from this
         /// function is never null.
         const ALLOCATOR                 = 1 << 1;
         /// `#[unwind]`: an indicator that this function may unwind despite what

src/librustc_codegen_llvm/lib.rs

@@ -10,7 +10,6 @@
 #![feature(box_syntax)]
 #![feature(const_cstr_unchecked)]
 #![feature(crate_visibility_modifier)]
-#![feature(custom_attribute)]
 #![feature(extern_types)]
 #![feature(in_band_lifetimes)]
 #![allow(unused_attributes)]

src/librustc_codegen_ssa/lib.rs

@@ -3,7 +3,6 @@
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(core_intrinsics)]
-#![feature(custom_attribute)]
 #![feature(libc)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(stmt_expr_attributes)]

src/librustc_codegen_utils/lib.rs

@@ -8,7 +8,6 @@
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(core_intrinsics)]
-#![feature(custom_attribute)]
 #![feature(never_type)]
 #![feature(nll)]
 #![allow(unused_attributes)]

src/librustc_errors/lib.rs

@@ -1,6 +1,5 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
-#![feature(custom_attribute)]
 #![allow(unused_attributes)]
 #![cfg_attr(unix, feature(libc))]
 #![feature(nll)]

src/librustc_save_analysis/lib.rs

@@ -1,5 +1,4 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
-#![feature(custom_attribute)]
 #![feature(nll)]
 #![deny(rust_2018_idioms)]
 #![deny(internal)]