Auto merge of rust-lang#108955 - Nilstrieb:dont-use-me-pls, r=oli-obk

Add `internal_features` lint

Implements rust-lang/compiler-team#596

Also requires some more test blessing for codegen tests etc

`@jyn514` had the idea of just `allow`ing the lint by default in the test suite. I'm not sure whether this is a good idea, but it's definitely one worth considering. Additional input encouraged.

Author: bors

alloc/src/lib.rs

@@ -88,6 +88,7 @@
 #![warn(missing_docs)]
 #![allow(explicit_outlives_requirements)]
 #![warn(multiple_supertrait_upcastable)]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
 //
 // Library features:
 // tidy-alphabetical-start

core/src/intrinsics/mir.rs

@@ -14,6 +14,7 @@
 //!
 //! ```rust
 //! #![feature(core_intrinsics, custom_mir)]
+#![cfg_attr(not(bootstrap), doc = "#![allow(internal_features)]")]
 //!
 //! use core::intrinsics::mir::*;
 //!
@@ -63,6 +64,7 @@
 //!
 //! ```rust
 //! #![feature(core_intrinsics, custom_mir)]
+#![cfg_attr(not(bootstrap), doc = "#![allow(internal_features)]")]
 //!
 //! use core::intrinsics::mir::*;
 //!
@@ -315,6 +317,7 @@ define!(
     /// # Examples
     ///
     /// ```rust
+    #[cfg_attr(not(bootstrap), doc = "#![allow(internal_features)]")]
     /// #![feature(custom_mir, core_intrinsics)]
     ///
     /// use core::intrinsics::mir::*;

core/src/lib.rs

@@ -96,6 +96,7 @@
 #![allow(explicit_outlives_requirements)]
 #![allow(incomplete_features)]
 #![warn(multiple_supertrait_upcastable)]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
 //
 // Library features:
 // tidy-alphabetical-start

panic_abort/src/lib.rs

@@ -14,6 +14,7 @@
 #![feature(staged_api)]
 #![feature(rustc_attrs)]
 #![feature(c_unwind)]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
 
 #[cfg(target_os = "android")]
 mod android;

panic_unwind/src/lib.rs

@@ -26,6 +26,7 @@
 #![feature(c_unwind)]
 // `real_imp` is unused with Miri, so silence warnings.
 #![cfg_attr(miri, allow(dead_code))]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
 
 use alloc::boxed::Box;
 use core::any::Any;

proc_macro/src/lib.rs

@@ -33,6 +33,7 @@
 #![feature(min_specialization)]
 #![feature(strict_provenance)]
 #![recursion_limit = "256"]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
 
 #[unstable(feature = "proc_macro_internals", issue = "27812")]
 #[doc(hidden)]

profiler_builtins/src/lib.rs

@@ -7,4 +7,5 @@
     issue = "none"
 )]
 #![allow(unused_features)]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
 #![feature(staged_api)]

std/src/lib.rs

@@ -220,6 +220,7 @@
 #![warn(missing_debug_implementations)]
 #![allow(explicit_outlives_requirements)]
 #![allow(unused_lifetimes)]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
 #![deny(rustc::existing_doc_keyword)]
 #![deny(fuzzy_provenance_casts)]
 // Ensure that std can be linked against panic_abort despite compiled with `-C panic=unwind`

test/src/lib.rs

@@ -21,6 +21,7 @@
 #![feature(process_exitcode_internals)]
 #![feature(panic_can_unwind)]
 #![feature(test)]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
 
 // Public reexports
 pub use self::bench::{black_box, Bencher};

unwind/src/lib.rs

@@ -5,6 +5,7 @@
 #![feature(c_unwind)]
 #![feature(cfg_target_abi)]
 #![cfg_attr(not(target_env = "msvc"), feature(libc))]
+#![cfg_attr(not(bootstrap), allow(internal_features))]
 
 cfg_if::cfg_if! {
     if #[cfg(target_env = "msvc")] {