add test for #54467

Author: arielb1

src/test/run-pass/issue-54467.rs

@@ -0,0 +1,54 @@
+// 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.
+
+pub trait Stream {
+    type Item;
+    type Error;
+}
+
+pub trait ParseError<I> {
+    type Output;
+}
+
+impl ParseError<char> for u32 {
+    type Output = ();
+}
+
+impl Stream for () {
+    type Item = char;
+    type Error = u32;
+}
+
+pub struct Lex<'a, I>
+    where I: Stream,
+          I::Error: ParseError<char>,
+          <<I as Stream>::Error as ParseError<char>>::Output: 'a
+{
+    x: &'a <I::Error as ParseError<char>>::Output
+}
+
+pub struct Reserved<'a, I> where
+    I: Stream<Item=char> + 'a,
+    I::Error: ParseError<I::Item>,
+//    <<I as Stream>::Error as ParseError<char>>::Output: 'a // comment this to compile
+
+{
+    x: Lex<'a, I>
+}
+
+fn main() {
+    let r: Reserved<()> = Reserved {
+        x: Lex {
+            x: &()
+        }
+    };
+
+    let _v = r.x.x;
+}