diff --git a/lib/cretonne/src/ir/extname.rs b/lib/cretonne/src/ir/extname.rs
index 273006b570..ba5ddba40b 100644
--- a/lib/cretonne/src/ir/extname.rs
+++ b/lib/cretonne/src/ir/extname.rs
@@ -5,6 +5,7 @@
 //! Cretonne, which compiles functions independently.
 
 use std::fmt::{self, Write};
+#[allow(unused_imports)]
 use std::ascii::AsciiExt;
 
 /// The name of an external can be any sequence of bytes.
diff --git a/lib/reader/src/lexer.rs b/lib/reader/src/lexer.rs
index 10cd9737af..c8b0ca96ad 100644
--- a/lib/reader/src/lexer.rs
+++ b/lib/reader/src/lexer.rs
@@ -7,6 +7,7 @@
 
 use std::str::CharIndices;
 use std::u16;
+#[allow(unused_imports)]
 use std::ascii::AsciiExt;
 use cretonne::ir::types;
 use cretonne::ir::{Value, Ebb};