diff --git a/src/librustdoc/json/conversions.rs b/src/librustdoc/json/conversions.rs
index de0240f28f7..60197a0dc1c 100644
--- a/src/librustdoc/json/conversions.rs
+++ b/src/librustdoc/json/conversions.rs
@@ -2,6 +2,8 @@
 //! the `clean` types but with some fields removed or stringified to simplify the output and not
 //! expose unstable compiler internals.
 
+#![allow(rustc::default_hash_types)]
+
 use std::convert::From;
 
 use rustc_ast::ast;