diff --git a/src/test/auxiliary/issue-21092.rs b/src/test/auxiliary/issue-21092.rs
new file mode 100644
index 000000000000..6d6046cc7bfc
--- /dev/null
+++ b/src/test/auxiliary/issue-21092.rs
@@ -0,0 +1,20 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub trait Foo {
+    type Bar;
+    fn foo(&self) {}
+}
+
+pub struct Bar;
+
+impl Foo for Bar {
+    type Bar = i32;
+}
diff --git a/src/test/rustdoc/issue-21092.rs b/src/test/rustdoc/issue-21092.rs
new file mode 100644
index 000000000000..30d61d76ab32
--- /dev/null
+++ b/src/test/rustdoc/issue-21092.rs
@@ -0,0 +1,17 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// aux-build:issue-21092.rs
+
+extern crate issue_21092;
+
+// @has issue_21092/struct.Bar.html
+// @has - '//*[@id="assoc_type.Bar"]' 'type Bar = i32'
+pub use issue_21092::{Foo, Bar};