Auto merge of #116830 - nnethercote:rustc_type_ir, r=compiler-errors

Remove `IdFunctor` trait.

It's defined in `rustc_data_structures` but is only used in
`rustc_type_ir`. The code is shorter and easier to read if we remove
this layer of abstraction and just do the things directly where they are
needed.

r? `@BoxyUwU`

compiler/rustc_data_structures/src/lib.rs

@@ -10,7 +10,6 @@
 #![cfg_attr(not(bootstrap), feature(rustdoc_internals))]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(array_windows)]
-#![feature(associated_type_bounds)]
 #![feature(auto_traits)]
 #![feature(cell_leak)]
 #![feature(core_intrinsics)]
@@ -21,15 +20,12 @@
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(type_alias_impl_trait)]
-#![feature(new_uninit)]
 #![feature(lazy_cell)]
 #![feature(rustc_attrs)]
 #![feature(negative_impls)]
 #![feature(test)]
 #![feature(thread_id_value)]
-#![feature(vec_into_raw_parts)]
 #![feature(allocator_api)]
-#![feature(get_mut_unchecked)]
 #![feature(lint_reasons)]
 #![feature(unwrap_infallible)]
 #![feature(strict_provenance)]
@@ -65,7 +61,6 @@ pub mod binary_search_util;
 pub mod captures;
 pub mod flat_map_in_place;
 pub mod flock;
-pub mod functor;
 pub mod fx;
 pub mod graph;
 pub mod intern;