diff --git a/rust/hglib/src/connection.rs b/rust/hglib/src/connection.rs
--- a/rust/hglib/src/connection.rs
+++ b/rust/hglib/src/connection.rs
@@ -15,7 +15,9 @@
 //!     conn.read_hello().expect("failed to read server hello");
 //! ```
 
+#[allow(unused_imports)]
 use std::ascii::AsciiExt;
+
 use std::error::Error;
 use std::fmt::{self, Display};
 use std::io;