diff options
| -rw-r--r-- | library/core/src/str/mod.rs | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs index ecc0613d7b9..b90f34360f6 100644 --- a/library/core/src/str/mod.rs +++ b/library/core/src/str/mod.rs @@ -1160,6 +1160,12 @@ impl str { /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a /// function or closure that determines if a character matches. /// + /// Note that there is a footgun to this method when using a slice of [`char`]s. + /// Some users may expect that a slice of chars will behave similarly to a `&str` with this method. + /// That is not currently the case. When you pass a slice of [`char`]s to this method, it will return true + /// if any of the [`char`]s in the slice is the first [`char`] of this string slice. It does not work for + /// sequentially comparing a slice of [`char`]s to a string slice. See the second example below. + /// /// [`char`]: prim@char /// [pattern]: self::pattern /// @@ -1171,6 +1177,14 @@ impl str { /// assert!(bananas.starts_with("bana")); /// assert!(!bananas.starts_with("nana")); /// ``` + /// + /// ``` + /// let bananas = "bananas"; + /// + /// // Note that both of these assert successfully. + /// assert!(bananas.starts_with(&['b', 'a', 'n', 'a'])); + /// assert!(bananas.starts_with(&['a', 'b', 'c', 'd'])); + /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn starts_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool { pat.is_prefix_of(self) |