Add truncate note to Vec::resize

[rust.git] / library / alloc / src / vec / mod.rs

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 2ee91f88d3c224a50dbe8c0c15d3421ad7ea554d..cc53df812bb5456bcd7fe232db8d9817ebe73d3f 100644 (file)
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1,8 +1,8 @@
 //! A contiguous growable array type with heap-allocated contents, written
 //! `Vec<T>`.
 //!
-//! Vectors have `O(1)` indexing, amortized `O(1)` push (to the end) and
-//! `O(1)` pop (from the end).
+//! Vectors have *O*(1) indexing, amortized *O*(1) push (to the end) and
+//! *O*(1) pop (from the end).
 //!
 //! Vectors ensure they never allocate more than `isize::MAX` bytes.
 //!
@@ -396,6 +396,7 @@
 /// [owned slice]: Box
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "vec_type")]
+#[rustc_insignificant_dtor]
 pub struct Vec<T, #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global> {
     buf: RawVec<T, A>,
     len: usize,
@@ -1270,7 +1271,7 @@ pub unsafe fn set_len(&mut self, new_len: usize) {
     ///
     /// The removed element is replaced by the last element of the vector.
     ///
-    /// This does not preserve ordering, but is O(1).
+    /// This does not preserve ordering, but is *O*(1).
     ///
     /// # Panics
     ///
@@ -2115,6 +2116,7 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
     /// in order to be able to clone the passed value.
     /// If you need more flexibility (or want to rely on [`Default`] instead of
     /// [`Clone`]), use [`Vec::resize_with`].
+    /// If you only need to resize to a smaller size, use [`Vec::truncate`].
     ///
     /// # Examples
     ///