From cc3abc4d2786be6d8366eb904b8ea4ac4a3e9f7e Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Wed, 17 Apr 2019 00:11:19 +0300
Subject: [PATCH] add a test for unsized index

---
 src/test/ui/unsized-locals/unsized-index.rs | 23 +++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 src/test/ui/unsized-locals/unsized-index.rs

diff --git a/src/test/ui/unsized-locals/unsized-index.rs b/src/test/ui/unsized-locals/unsized-index.rs
new file mode 100644
index 0000000000000..2e6bd82bda302
--- /dev/null
+++ b/src/test/ui/unsized-locals/unsized-index.rs
@@ -0,0 +1,23 @@
+// compile-pass
+
+// `std::ops::Index` has an `: ?Sized` bound on the `Idx` type param. This is
+// an accidental left-over from the times when it `Index` was by-reference.
+// Tightening the bound now could be a breaking change. Although no crater
+// regression were observed (https://github.com/rust-lang/rust/pull/59527),
+// let's be conservative and just add a test for this.
+#![feature(unsized_locals)]
+
+use std::ops;
+
+pub struct A;
+
+impl ops::Index<str> for A {
+    type Output = ();
+    fn index(&self, _: str) -> &Self::Output { panic!() }
+}
+
+impl ops::IndexMut<str> for A {
+    fn index_mut(&mut self, _: str) -> &mut Self::Output { panic!() }
+}
+
+fn main() {}