Rollup merge of rust-lang#141108 - PaulDance:fix-extract_if-docs, r=Mark-Simulacrum

Docs(lib): Fix `extract_if` docs

Various fixes to the documentation comments of the several `extract_if` collection methods available. It originally started with a small typo fix in `Vec`'s spotted when reading the 1.87 release notes, but then by looking at the others' for comparison in order to try determining what was the intended sentence, some inconsistencies were spotted. Therefore, some other changes are also proposed here to reduce these avoidable differences, going more and more nit-picky along the way. See the individual commits for more details about each change.

`@rustbot` label T-libs A-collections A-docs

Author: jhpratt

library/alloc/src/collections/btree/map.rs

@@ -1398,10 +1398,12 @@ impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
     }
 
     /// Creates an iterator that visits all elements (key-value pairs) in
-    /// ascending key order and uses a closure to determine if an element should
-    /// be removed. If the closure returns `true`, the element is removed from
-    /// the map and yielded. If the closure returns `false`, or panics, the
-    /// element remains in the map and will not be yielded.
+    /// ascending key order and uses a closure to determine if an element
+    /// should be removed.
+    ///
+    /// If the closure returns `true`, the element is removed from the map and
+    /// yielded. If the closure returns `false`, or panics, the element remains
+    /// in the map and will not be yielded.
     ///
     /// The iterator also lets you mutate the value of each element in the
     /// closure, regardless of whether you choose to keep or remove it.

library/alloc/src/collections/linked_list.rs

@@ -1124,20 +1124,20 @@ impl<T, A: Allocator> LinkedList<T, A> {
 
     /// Creates an iterator which uses a closure to determine if an element should be removed.
     ///
-    /// If the closure returns true, then the element is removed and yielded.
-    /// If the closure returns false, the element will remain in the list and will not be yielded
-    /// by the iterator.
+    /// If the closure returns `true`, the element is removed from the list and
+    /// yielded. If the closure returns `false`, or panics, the element remains
+    /// in the list and will not be yielded.
     ///
     /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
     /// or the iteration short-circuits, then the remaining elements will be retained.
     /// Use `extract_if().for_each(drop)` if you do not need the returned iterator.
     ///
-    /// Note that `extract_if` lets you mutate every element in the filter closure, regardless of
-    /// whether you choose to keep or remove it.
+    /// The iterator also lets you mutate the value of each element in the
+    /// closure, regardless of whether you choose to keep or remove it.
     ///
     /// # Examples
     ///
-    /// Splitting a list into evens and odds, reusing the original list:
+    /// Splitting a list into even and odd values, reusing the original list:
     ///
     /// ```
     /// use std::collections::LinkedList;

library/alloc/src/vec/mod.rs

@@ -3648,11 +3648,11 @@ impl<T, A: Allocator> Vec<T, A> {
         Splice { drain: self.drain(range), replace_with: replace_with.into_iter() }
     }
 
-    /// Creates an iterator which uses a closure to determine if element in the range should be removed.
+    /// Creates an iterator which uses a closure to determine if an element in the range should be removed.
     ///
-    /// If the closure returns true, then the element is removed and yielded.
-    /// If the closure returns false, the element will remain in the vector and will not be yielded
-    /// by the iterator.
+    /// If the closure returns `true`, the element is removed from the vector
+    /// and yielded. If the closure returns `false`, or panics, the element
+    /// remains in the vector and will not be yielded.
     ///
     /// Only elements that fall in the provided range are considered for extraction, but any elements
     /// after the range will still have to be moved if any element has been extracted.
@@ -3692,16 +3692,16 @@ impl<T, A: Allocator> Vec<T, A> {
     /// But `extract_if` is easier to use. `extract_if` is also more efficient,
     /// because it can backshift the elements of the array in bulk.
     ///
-    /// Note that `extract_if` also lets you mutate the elements passed to the filter closure,
-    /// regardless of whether you choose to keep or remove them.
+    /// The iterator also lets you mutate the value of each element in the
+    /// closure, regardless of whether you choose to keep or remove it.
     ///
     /// # Panics
     ///
     /// If `range` is out of bounds.
     ///
     /// # Examples
     ///
-    /// Splitting an array into evens and odds, reusing the original allocation:
+    /// Splitting a vector into even and odd values, reusing the original vector:
     ///
     /// ```
     /// let mut numbers = vec![1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15];

library/std/src/collections/hash/map.rs

@@ -648,14 +648,14 @@ impl<K, V, S> HashMap<K, V, S> {
         Drain { base: self.base.drain() }
     }
 
-    /// Creates an iterator which uses a closure to determine if an element should be removed.
+    /// Creates an iterator which uses a closure to determine if an element (key-value pair) should be removed.
     ///
-    /// If the closure returns true, the element is removed from the map and yielded.
-    /// If the closure returns false, or panics, the element remains in the map and will not be
-    /// yielded.
+    /// If the closure returns `true`, the element is removed from the map and
+    /// yielded. If the closure returns `false`, or panics, the element remains
+    /// in the map and will not be yielded.
     ///
-    /// Note that `extract_if` lets you mutate every value in the filter closure, regardless of
-    /// whether you choose to keep or remove it.
+    /// The iterator also lets you mutate the value of each element in the
+    /// closure, regardless of whether you choose to keep or remove it.
     ///
     /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
     /// or the iteration short-circuits, then the remaining elements will be retained.

library/std/src/collections/hash/set.rs

@@ -276,11 +276,11 @@ impl<T, S> HashSet<T, S> {
         Drain { base: self.base.drain() }
     }
 
-    /// Creates an iterator which uses a closure to determine if a value should be removed.
+    /// Creates an iterator which uses a closure to determine if an element should be removed.
     ///
-    /// If the closure returns true, then the value is removed and yielded.
-    /// If the closure returns false, the value will remain in the list and will not be yielded
-    /// by the iterator.
+    /// If the closure returns `true`, the element is removed from the set and
+    /// yielded. If the closure returns `false`, or panics, the element remains
+    /// in the set and will not be yielded.
     ///
     /// If the returned `ExtractIf` is not exhausted, e.g. because it is dropped without iterating
     /// or the iteration short-circuits, then the remaining elements will be retained.