diff --git a/serde_derive_internals/src/case.rs b/serde_derive_internals/src/case.rs
index 1fa1ae7d..75c38e48 100644
--- a/serde_derive_internals/src/case.rs
+++ b/serde_derive_internals/src/case.rs
@@ -6,7 +6,10 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// See https://users.rust-lang.org/t/psa-dealing-with-warning-unused-import-std-ascii-asciiext-in-today-s-nightly/13726
+#[allow(unused_imports)]
 use std::ascii::AsciiExt;
+
 use std::str::FromStr;
 
 use self::RenameRule::*;