Auto merge of rust-lang#116168 - matthiaskrgr:rollup-ys1zmk1, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#116099 (Add regression test for issue rust-lang#79865)
 - rust-lang#116102 (Correct codegen of `ConstValue::Indirect` scalar and scalar pair)
 - rust-lang#116131 (Rename `cold_path` to `outline`)
 - rust-lang#116144 (subst -> instantiate)
 - rust-lang#116151 (Fix typo in rustdoc unstable features doc)
 - rust-lang#116153 (Update books)
 - rust-lang#116162 (Gate and validate `#[rustc_safe_intrinsic]`)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_arena/src/lib.rs

@@ -37,9 +37,10 @@ use std::ptr::{self, NonNull};
 use std::slice;
 use std::{cmp, intrinsics};
 
+/// This calls the passed function while ensuring it won't be inlined into the caller.
 #[inline(never)]
 #[cold]
-fn cold_path<F: FnOnce() -> R, R>(f: F) -> R {
+fn outline<F: FnOnce() -> R, R>(f: F) -> R {
     f()
 }
 
@@ -600,7 +601,7 @@ impl DroplessArena {
                 unsafe { self.write_from_iter(iter, len, mem) }
             }
             (_, _) => {
-                cold_path(move || -> &mut [T] {
+                outline(move || -> &mut [T] {
                     let mut vec: SmallVec<[_; 8]> = iter.collect();
                     if vec.is_empty() {
                         return &mut [];

compiler/rustc_ast_lowering/src/lib.rs

@@ -1664,7 +1664,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     lifetime.ident,
                 ));
 
-                // Now make an arg that we can use for the substs of the opaque tykind.
+                // Now make an arg that we can use for the generic params of the opaque tykind.
                 let id = self.next_node_id();
                 let lifetime_arg = self.new_named_lifetime_with_res(id, lifetime.ident, res);
                 let duplicated_lifetime_def_id = self.local_def_id(duplicated_lifetime_node_id);