is_ascii on an empty string or slice returns true

Author: timvisee

library/core/src/slice/ascii.rs

@@ -9,6 +9,8 @@ use crate::{ascii, iter, ops};
 
 impl [u8] {
     /// Checks if all bytes in this slice are within the ASCII range.
+    ///
+    /// An empty slice returns `true`.
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
     #[rustc_const_stable(feature = "const_slice_is_ascii", since = "1.74.0")]
     #[must_use]

library/core/src/str/mod.rs

@@ -2704,6 +2704,8 @@ impl str {
 
     /// Checks if all characters in this string are within the ASCII range.
     ///
+    /// An empty string returns `true`.
+    ///
     /// # Examples
     ///
     /// ```

library/std/src/ffi/os_str.rs

@@ -1215,6 +1215,8 @@ impl OsStr {
 
     /// Checks if all characters in this string are within the ASCII range.
     ///
+    /// An empty string returns `true`.
+    ///
     /// # Examples
     ///
     /// ```