Convert conservative_impl_trait.rs to compile-pass

src/test/ui/traits/conservative_impl_trait.rs

@@ -0,0 +1,18 @@
+// Copyright 2017 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.
+
+// compile-pass
+// #39665
+
+fn batches(n: &u32) -> impl Iterator<Item=&u32> {
+    std::iter::once(n)
+}
+
+fn main() {}