Support unstable moves via stable in unstable items

Author: yaahc

core/src/intrinsics.rs

@@ -2649,6 +2649,7 @@ pub const unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) {
 /// Here is an example of how this could cause a problem:
 /// ```no_run
 /// #![feature(const_eval_select)]
+/// #![feature(core_intrinsics)]
 /// use std::hint::unreachable_unchecked;
 /// use std::intrinsics::const_eval_select;
 ///

core/src/unicode/mod.rs

@@ -1,7 +1,9 @@
-#![unstable(feature = "unicode_internals", issue = "none")]
+#![stable(feature = "unicode_version", since = "1.45.0")]
 #![allow(missing_docs)]
 
+#[unstable(feature = "unicode_internals", issue = "none")]
 pub(crate) mod printable;
+#[unstable(feature = "unicode_internals", issue = "none")]
 mod unicode_data;
 
 /// The version of [Unicode](https://www.unicode.org/) that the Unicode parts of
@@ -18,6 +20,7 @@ mod unicode_data;
 pub const UNICODE_VERSION: (u8, u8, u8) = unicode_data::UNICODE_VERSION;
 
 // For use in liballoc, not re-exported in libstd.
+#[unstable(feature = "unicode_internals", issue = "none")]
 pub use unicode_data::{
     case_ignorable::lookup as Case_Ignorable, cased::lookup as Cased, conversions,
 };

std/src/lib.rs

@@ -214,7 +214,7 @@
 #![cfg_attr(not(bootstrap), deny(ffi_unwind_calls))]
 // std may use features in a platform-specific way
 #![allow(unused_features)]
-#![cfg_attr(test, feature(internal_output_capture, print_internals, update_panic_count))]
+#![cfg_attr(test, feature(internal_output_capture, print_internals, update_panic_count, rt))]
 #![cfg_attr(
     all(target_vendor = "fortanix", target_env = "sgx"),
     feature(slice_index_methods, coerce_unsized, sgx_platform)
@@ -297,6 +297,7 @@
 // Library features (alloc):
 #![feature(alloc_layout_extra)]
 #![feature(alloc_c_string)]
+#![feature(alloc_ffi)]
 #![feature(allocator_api)]
 #![feature(get_mut_unchecked)]
 #![feature(map_try_insert)]

std/src/panic.rs

@@ -11,7 +11,7 @@ use crate::thread::Result;
 
 #[doc(hidden)]
 #[unstable(feature = "edition_panic", issue = "none", reason = "use panic!() instead")]
-#[allow_internal_unstable(libstd_sys_internals, const_format_args, core_panic)]
+#[allow_internal_unstable(libstd_sys_internals, const_format_args, core_panic, rt)]
 #[cfg_attr(not(test), rustc_diagnostic_item = "std_panic_2015_macro")]
 #[rustc_macro_transparency = "semitransparent"]
 pub macro panic_2015 {