Auto merge of #72036 - Dylan-DPC:rollup-ca8b0ql, r=Dylan-DPC

Rollup of 8 pull requests

Successful merges:

 - #70834 (Add core::future::{pending,ready})
 - #71839 (Make BTreeMap::new and BTreeSet::new const)
 - #71890 (Simplify the error Registry methods a little)
 - #71942 (Shrink `LocalDecl`)
 - #71947 (Dead-code pass highlights too much of impl functions)
 - #71981 (Fix `strip-priv-imports` pass name in the rustdoc documentation)
 - #72018 (Fix canonicalization links)
 - #72031 (Better documentation for io::Read::read() return value)

Failed merges:

r? @ghost

3 files changed, 5 insertions, 2 deletions

diff --git a/src/liballoc/collections/btree/map.rs b/src/liballoc/collections/btree/map.rs
index 98a94d695f7..113df80d0c2 100644
--- a/src/liballoc/collections/btree/map.rs
+++ b/src/liballoc/collections/btree/map.rs
@@ -556,7 +556,8 @@ impl<K: Ord, V> BTreeMap<K, V> {
     /// map.insert(1, "a");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn new() -> BTreeMap<K, V> {
+    #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+    pub const fn new() -> BTreeMap<K, V> {
         BTreeMap { root: None, length: 0 }
     }
 
diff --git a/src/liballoc/collections/btree/set.rs b/src/liballoc/collections/btree/set.rs
index 9bf483f269f..dee5fb878ff 100644
--- a/src/liballoc/collections/btree/set.rs
+++ b/src/liballoc/collections/btree/set.rs
@@ -309,7 +309,8 @@ impl<T: Ord> BTreeSet<T> {
     /// let mut set: BTreeSet<i32> = BTreeSet::new();
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn new() -> BTreeSet<T> {
+    #[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+    pub const fn new() -> BTreeSet<T> {
         BTreeSet { map: BTreeMap::new() }
     }
 
diff --git a/src/liballoc/lib.rs b/src/liballoc/lib.rs
index ecec1fb039b..5365c9d0168 100644
--- a/src/liballoc/lib.rs
+++ b/src/liballoc/lib.rs
@@ -82,6 +82,7 @@
 #![feature(cfg_sanitize)]
 #![feature(cfg_target_has_atomic)]
 #![feature(coerce_unsized)]
+#![feature(const_btree_new)]
 #![feature(const_generic_impls_guard)]
 #![feature(const_generics)]
 #![feature(const_in_array_repeat_expressions)]