Auto merge of #120730 - estebank:confusable-api, r=oli-obk

Provide suggestions through `rustc_confusables` annotations

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();
   |       ~~~~~~
```

Fix #59450 (we can open subsequent tickets for specific cases).

Fix #108437:

```
error[E0599]: `Option<{integer}>` is not an iterator
   --> f101.rs:3:9
    |
3   |     opt.flat_map(|val| Some(val));
    |         ^^^^^^^^ `Option<{integer}>` is not an iterator
    |
   ::: /home/gh-estebank/rust/library/core/src/option.rs:571:1
    |
571 | pub enum Option<T> {
    | ------------------ doesn't satisfy `Option<{integer}>: Iterator`
    |
    = note: the following trait bounds were not satisfied:
            `Option<{integer}>: Iterator`
            which is required by `&mut Option<{integer}>: Iterator`
help: you might have meant to use `and_then`
    |
3   |     opt.and_then(|val| Some(val));
    |         ~~~~~~~~
```

On type error of method call arguments, look at confusables for suggestion. Fix #87212:

```
error[E0308]: mismatched types
    --> f101.rs:8:18
     |
8    |     stuff.append(Thing);
     |           ------ ^^^^^ expected `&mut Vec<Thing>`, found `Thing`
     |           |
     |           arguments to this method are incorrect
     |
     = note: expected mutable reference `&mut Vec<Thing>`
                           found struct `Thing`
note: method defined here
    --> /home/gh-estebank/rust/library/alloc/src/vec/mod.rs:2025:12
     |
2025 |     pub fn append(&mut self, other: &mut Self) {
     |            ^^^^^^
help: you might have meant to use `push`
     |
8    |     stuff.push(Thing);
     |           ~~~~
```

5 files changed, 9 insertions, 0 deletions

diff --git a/library/std/src/collections/hash/map.rs b/library/std/src/collections/hash/map.rs
index 0d4c1fa05cc..627befb63a1 100644
--- a/library/std/src/collections/hash/map.rs
+++ b/library/std/src/collections/hash/map.rs
@@ -1101,6 +1101,7 @@ where
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("push", "append")]
     pub fn insert(&mut self, k: K, v: V) -> Option<V> {
         self.base.insert(k, v)
     }
@@ -1155,6 +1156,7 @@ where
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("delete", "take")]
     pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>
     where
         K: Borrow<Q>,
diff --git a/library/std/src/collections/hash/set.rs b/library/std/src/collections/hash/set.rs
index dcb2fa0f771..371201ff44c 100644
--- a/library/std/src/collections/hash/set.rs
+++ b/library/std/src/collections/hash/set.rs
@@ -885,6 +885,7 @@ where
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("push", "append")]
     pub fn insert(&mut self, value: T) -> bool {
         self.base.insert(value)
     }
@@ -906,6 +907,7 @@ where
     /// ```
     #[inline]
     #[stable(feature = "set_recovery", since = "1.9.0")]
+    #[rustc_confusables("swap")]
     pub fn replace(&mut self, value: T) -> Option<T> {
         self.base.replace(value)
     }
@@ -930,6 +932,7 @@ where
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("delete", "take")]
     pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool
     where
         T: Borrow<Q>,
diff --git a/library/std/src/ffi/os_str.rs b/library/std/src/ffi/os_str.rs
index 28747ad8f34..bbcbbc52843 100644
--- a/library/std/src/ffi/os_str.rs
+++ b/library/std/src/ffi/os_str.rs
@@ -255,6 +255,7 @@ impl OsString {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
+    #[rustc_confusables("append", "put")]
     pub fn push<T: AsRef<OsStr>>(&mut self, s: T) {
         self.inner.push_slice(&s.as_ref().inner)
     }
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 60562f64c90..89fbd5c4c64 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -1270,6 +1270,7 @@ impl PathBuf {
     /// assert_eq!(path, PathBuf::from("/etc"));
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_confusables("append", "put")]
     pub fn push<P: AsRef<Path>>(&mut self, path: P) {
         self._push(path.as_ref())
     }
diff --git a/library/std/src/thread/local.rs b/library/std/src/thread/local.rs
index d1213e2f166..34d30a259ee 100644
--- a/library/std/src/thread/local.rs
+++ b/library/std/src/thread/local.rs
@@ -435,6 +435,7 @@ impl<T: 'static> LocalKey<Cell<T>> {
     /// assert_eq!(X.replace(3), 2);
     /// ```
     #[stable(feature = "local_key_cell_methods", since = "1.73.0")]
+    #[rustc_confusables("swap")]
     pub fn replace(&'static self, value: T) -> T {
         self.with(|cell| cell.replace(value))
     }
@@ -606,6 +607,7 @@ impl<T: 'static> LocalKey<RefCell<T>> {
     /// X.with_borrow(|v| assert_eq!(*v, vec![1, 2, 3]));
     /// ```
     #[stable(feature = "local_key_cell_methods", since = "1.73.0")]
+    #[rustc_confusables("swap")]
     pub fn replace(&'static self, value: T) -> T {
         self.with(|cell| cell.replace(value))
     }