From 02f75247d0c60d295e24ac62f9522e21c81e8672 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Tue, 1 May 2018 14:33:17 +0200
Subject: [PATCH] Fix rustdoc ICE for impl trait in argument position

---
 src/librustdoc/clean/mod.rs                   |  1 -
 .../rustdoc/ice-impl-trait-arg-position.rs    | 24 +++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 src/test/rustdoc/ice-impl-trait-arg-position.rs

diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index bd64ac67ac93e..a301ff738e154 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -4048,7 +4048,6 @@ where
 
     let old_bounds = mem::replace(&mut *cx.impl_trait_bounds.borrow_mut(), bounds);
     let r = f();
-    assert!(cx.impl_trait_bounds.borrow().is_empty());
     *cx.impl_trait_bounds.borrow_mut() = old_bounds;
     r
 }
diff --git a/src/test/rustdoc/ice-impl-trait-arg-position.rs b/src/test/rustdoc/ice-impl-trait-arg-position.rs
new file mode 100644
index 0000000000000..2663ab322ab95
--- /dev/null
+++ b/src/test/rustdoc/ice-impl-trait-arg-position.rs
@@ -0,0 +1,24 @@
+// Copyright 2018 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.
+
+use std::io::Read;
+
+pub struct D<R>(R);
+
+pub struct A;
+impl A {
+    pub fn a(&self, d: impl IntoIterator<Item = D<impl Read>>) -> Result<(), ()> {
+        unimplemented!()
+    }
+
+    pub fn b(&self, d: impl IntoIterator<Item = D<()>>) -> Result<(), ()> {
+        unimplemented!()
+    }
+}