Only record the same impl once

Due to inlining it is possible to visit the same module multiple times
during `<Cache as DocFolder>::fold_crate`, so we keep track of the
modules we've already visited.

1 files changed, 22 insertions, 0 deletions

diff --git a/src/test/rustdoc/duplicate_impls/impls.rs b/src/test/rustdoc/duplicate_impls/impls.rs
new file mode 100644
index 00000000000..72e54fe733c
--- /dev/null
+++ b/src/test/rustdoc/duplicate_impls/impls.rs
@@ -0,0 +1,22 @@
+// Copyright 2016 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 struct Foo;
+
+// just so that `Foo` doesn't show up on `Bar`s sidebar
+pub mod bar {
+    pub trait Bar {}
+}
+
+impl Foo {
+    pub fn new() -> Foo { Foo }
+}
+
+impl bar::Bar for Foo {}