Add `rustc_confusables` annotations to some stdlib APIs

Help with common API confusion, like asking for `push` when the data structure really has `append`.

```
error[E0599]: no method named `size` found for struct `Vec<{integer}>` in the current scope
  --> $DIR/rustc_confusables_std_cases.rs:17:7
   |
LL |     x.size();
   |       ^^^^
   |
help: you might have meant to use `len`
   |
LL |     x.len();
   |       ~~~
help: there is a method with a similar name
   |
LL |     x.resize();
   |       ~~~~~~
```

#59450

8 files changed, 34 insertions, 0 deletions

diff --git a/library/alloc/src/collections/binary_heap/mod.rs b/library/alloc/src/collections/binary_heap/mod.rs
index c89a3806280..83b2678f7f5 100644
--- a/library/alloc/src/collections/binary_heap/mod.rs
+++ b/library/alloc/src/collections/binary_heap/mod.rs
@@ -607,6 +607,7 @@ impl<T: Ord, A: Allocator> BinaryHeap<T, A> {
     /// occurs when capacity is exhausted and needs a resize. The resize cost
     /// has been amortized in the previous figures.
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("append", "put")]
     pub fn push(&mut self, item: T) {
         let old_len = self.len();
         self.data.push(item);
@@ -1264,6 +1265,7 @@ impl<T, A: Allocator> BinaryHeap<T, A> {
     /// ```
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("length", "size")]
     pub fn len(&self) -> usize {
         self.data.len()
     }
diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index addcc71a2d4..80be4ee57c5 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -979,6 +979,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
     /// assert_eq!(map[&37], "c");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("push", "put", "set")]
     pub fn insert(&mut self, key: K, value: V) -> Option<V>
     where
         K: Ord,
@@ -1041,6 +1042,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
     /// assert_eq!(map.remove(&1), None);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("delete", "take")]
     pub fn remove<Q: ?Sized>(&mut self, key: &Q) -> Option<V>
     where
         K: Borrow<Q> + Ord,
@@ -2495,6 +2497,7 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
         issue = "71835",
         implied_by = "const_btree_new"
     )]
+    #[rustc_confusables("length", "size")]
     pub const fn len(&self) -> usize {
         self.length
     }
diff --git a/library/alloc/src/collections/btree/map/entry.rs b/library/alloc/src/collections/btree/map/entry.rs
index e9366eec9ce..0a894258f46 100644
--- a/library/alloc/src/collections/btree/map/entry.rs
+++ b/library/alloc/src/collections/btree/map/entry.rs
@@ -347,6 +347,7 @@ impl<'a, K: Ord, V, A: Allocator + Clone> VacantEntry<'a, K, V, A> {
     /// assert_eq!(map["poneyland"], 37);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("push", "put")]
     pub fn insert(mut self, value: V) -> &'a mut V {
         let out_ptr = match self.handle {
             None => {
@@ -524,6 +525,7 @@ impl<'a, K: Ord, V, A: Allocator + Clone> OccupiedEntry<'a, K, V, A> {
     /// assert_eq!(map["poneyland"], 15);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("push", "put")]
     pub fn insert(&mut self, value: V) -> V {
         mem::replace(self.get_mut(), value)
     }
@@ -546,6 +548,7 @@ impl<'a, K: Ord, V, A: Allocator + Clone> OccupiedEntry<'a, K, V, A> {
     /// // println!("{}", map["poneyland"]);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("delete", "take")]
     pub fn remove(self) -> V {
         self.remove_kv().1
     }
diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs
index 0e03551286e..ed91ae1a66e 100644
--- a/library/alloc/src/collections/btree/set.rs
+++ b/library/alloc/src/collections/btree/set.rs
@@ -790,6 +790,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
     /// ```
     #[must_use]
     #[stable(feature = "map_first_last", since = "1.66.0")]
+    #[rustc_confusables("front")]
     pub fn first(&self) -> Option<&T>
     where
         T: Ord,
@@ -816,6 +817,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
     /// ```
     #[must_use]
     #[stable(feature = "map_first_last", since = "1.66.0")]
+    #[rustc_confusables("back")]
     pub fn last(&self) -> Option<&T>
     where
         T: Ord,
@@ -896,6 +898,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
     /// assert_eq!(set.len(), 1);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("push", "put")]
     pub fn insert(&mut self, value: T) -> bool
     where
         T: Ord,
@@ -919,6 +922,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
     /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 10);
     /// ```
     #[stable(feature = "set_recovery", since = "1.9.0")]
+    #[rustc_confusables("swap")]
     pub fn replace(&mut self, value: T) -> Option<T>
     where
         T: Ord,
@@ -1152,6 +1156,7 @@ impl<T, A: Allocator + Clone> BTreeSet<T, A> {
         issue = "71835",
         implied_by = "const_btree_new"
     )]
+    #[rustc_confusables("length", "size")]
     pub const fn len(&self) -> usize {
         self.map.len()
     }
diff --git a/library/alloc/src/collections/linked_list.rs b/library/alloc/src/collections/linked_list.rs
index 9e109feb3d3..6dfb82ac807 100644
--- a/library/alloc/src/collections/linked_list.rs
+++ b/library/alloc/src/collections/linked_list.rs
@@ -656,6 +656,7 @@ impl<T, A: Allocator> LinkedList<T, A> {
     #[inline]
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("length", "size")]
     pub fn len(&self) -> usize {
         self.len
     }
@@ -740,6 +741,7 @@ impl<T, A: Allocator> LinkedList<T, A> {
     #[inline]
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("first")]
     pub fn front(&self) -> Option<&T> {
         unsafe { self.head.as_ref().map(|node| &node.as_ref().element) }
     }
@@ -890,6 +892,7 @@ impl<T, A: Allocator> LinkedList<T, A> {
     /// assert_eq!(3, *d.back().unwrap());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("push", "append")]
     pub fn push_back(&mut self, elt: T) {
         let node = Box::new_in(Node::new(elt), &self.alloc);
         let node_ptr = NonNull::from(Box::leak(node));
@@ -1004,6 +1007,7 @@ impl<T, A: Allocator> LinkedList<T, A> {
     /// assert_eq!(d.remove(0), 1);
     /// ```
     #[unstable(feature = "linked_list_remove", issue = "69210")]
+    #[rustc_confusables("delete", "take")]
     pub fn remove(&mut self, at: usize) -> T {
         let len = self.len();
         assert!(at < len, "Cannot remove at an index outside of the list bounds");
@@ -1478,6 +1482,7 @@ impl<'a, T, A: Allocator> Cursor<'a, T, A> {
     /// or None if the list is empty.
     #[must_use]
     #[unstable(feature = "linked_list_cursors", issue = "58533")]
+    #[rustc_confusables("first")]
     pub fn front(&self) -> Option<&'a T> {
         self.list.front()
     }
@@ -1486,6 +1491,7 @@ impl<'a, T, A: Allocator> Cursor<'a, T, A> {
     /// or None if the list is empty.
     #[must_use]
     #[unstable(feature = "linked_list_cursors", issue = "58533")]
+    #[rustc_confusables("last")]
     pub fn back(&self) -> Option<&'a T> {
         self.list.back()
     }
@@ -1788,6 +1794,7 @@ impl<'a, T, A: Allocator> CursorMut<'a, T, A> {
     ///
     /// This operation should compute in *O*(1) time.
     #[unstable(feature = "linked_list_cursors", issue = "58533")]
+    #[rustc_confusables("push", "append")]
     pub fn push_back(&mut self, elt: T) {
         // Safety: We know that `push_back` does not change the position in
         // memory of other nodes. This ensures that `self.current` remains
@@ -1834,6 +1841,7 @@ impl<'a, T, A: Allocator> CursorMut<'a, T, A> {
     ///
     /// This operation should compute in *O*(1) time.
     #[unstable(feature = "linked_list_cursors", issue = "58533")]
+    #[rustc_confusables("pop")]
     pub fn pop_back(&mut self) -> Option<T> {
         if self.list.is_empty() {
             None
@@ -1854,6 +1862,7 @@ impl<'a, T, A: Allocator> CursorMut<'a, T, A> {
     /// or None if the list is empty.
     #[must_use]
     #[unstable(feature = "linked_list_cursors", issue = "58533")]
+    #[rustc_confusables("first")]
     pub fn front(&self) -> Option<&T> {
         self.list.front()
     }
@@ -1870,6 +1879,7 @@ impl<'a, T, A: Allocator> CursorMut<'a, T, A> {
     /// or None if the list is empty.
     #[must_use]
     #[unstable(feature = "linked_list_cursors", issue = "58533")]
+    #[rustc_confusables("last")]
     pub fn back(&self) -> Option<&T> {
         self.list.back()
     }
diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index bcba6525fda..c35bab5ef66 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -1209,6 +1209,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// assert_eq!(deque.len(), 1);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("length", "size")]
     pub fn len(&self) -> usize {
         self.len
     }
@@ -1491,6 +1492,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// assert_eq!(d.front(), Some(&1));
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("first")]
     pub fn front(&self) -> Option<&T> {
         self.get(0)
     }
@@ -1535,6 +1537,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// assert_eq!(d.back(), Some(&2));
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("last")]
     pub fn back(&self) -> Option<&T> {
         self.get(self.len.wrapping_sub(1))
     }
@@ -1654,6 +1657,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// assert_eq!(3, *buf.back().unwrap());
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("push", "put", "append")]
     pub fn push_back(&mut self, value: T) {
         if self.is_full() {
             self.grow();
@@ -1813,6 +1817,7 @@ impl<T, A: Allocator> VecDeque<T, A> {
     /// assert_eq!(buf, [1, 3]);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("delete", "take")]
     pub fn remove(&mut self, index: usize) -> Option<T> {
         if self.len <= index {
             return None;
diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index 4d6968157de..6ad783bee27 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -1445,6 +1445,7 @@ impl String {
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("delete", "take")]
     pub fn remove(&mut self, idx: usize) -> char {
         let ch = match self[idx..].chars().next() {
             Some(ch) => ch,
@@ -1639,6 +1640,7 @@ impl String {
     #[cfg(not(no_global_oom_handling))]
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("set")]
     pub fn insert(&mut self, idx: usize, ch: char) {
         assert!(self.is_char_boundary(idx));
         let mut bits = [0; 4];
@@ -1738,6 +1740,7 @@ impl String {
     #[inline]
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("length", "size")]
     pub fn len(&self) -> usize {
         self.vec.len()
     }
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 08e3cdedc66..b59699219eb 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1554,6 +1554,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[track_caller]
+    #[rustc_confusables("delete", "take")]
     pub fn remove(&mut self, index: usize) -> T {
         #[cold]
         #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
@@ -1915,6 +1916,7 @@ impl<T, A: Allocator> Vec<T, A> {
     #[cfg(not(no_global_oom_handling))]
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("push_back", "put", "append")]
     pub fn push(&mut self, value: T) {
         // This will panic or abort if we would allocate > isize::MAX bytes
         // or if the length increment would overflow for zero-sized types.
@@ -2141,6 +2143,7 @@ impl<T, A: Allocator> Vec<T, A> {
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("length", "size")]
     pub fn len(&self) -> usize {
         self.len
     }