Known problems

clippy_lints/src/transmute.rs

@@ -96,11 +96,20 @@ declare_lint! {
     "transmutes from an integer to a `char`"
 }
 
-/// **What it does:** Checks for transmutes from a `&[u8] to a `&str`.
+/// **What it does:** Checks for transmutes from a `&[u8]` to a `&str`.
 ///
 /// **Why is this bad?** Not every byte slice is a valid UTF-8 string.
 ///
-/// **Known problems:** None.
+/// **Known problems:**
+/// - [`from_utf8`] which this lint suggests using is slower than `transmute`
+/// as it needs to validate the input.
+/// If you are certain that the input is always a valid UTF-8,
+/// use [`from_utf8_unchecked`] which is as fast as `transmute`
+/// but has a semantically meaningful name.
+/// - You might want to handle errors returned from [`from_utf8`] instead of calling `unwrap`.
+///
+/// [`from_utf8`]: https://doc.rust-lang.org/std/str/fn.from_utf8.html
+/// [`from_utf8_unchecked`]: https://doc.rust-lang.org/std/str/fn.from_utf8_unchecked.html
 ///
 /// **Example:**
 /// ```rust