2 files changed, 28 insertions, 0 deletions
diff --git a/src/test/ui/suggestions/dont-suggest-dereference-on-arg.rs b/src/test/ui/suggestions/dont-suggest-dereference-on-arg.rs
new file mode 100644
index 00000000000..2a9ea464416
--- /dev/null
+++ b/src/test/ui/suggestions/dont-suggest-dereference-on-arg.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.
+
+fn foo(s: &str) -> bool { true }
+
+fn main() {
+    let x = vec![(String::new(), String::new())];
+    x.iter()
+        .filter(|&(ref a, _)| foo(a))
+        .collect();
+}
diff --git a/src/test/ui/suggestions/dont-suggest-dereference-on-arg.stderr b/src/test/ui/suggestions/dont-suggest-dereference-on-arg.stderr
new file mode 100644
index 00000000000..fc1eb335d05
--- /dev/null
+++ b/src/test/ui/suggestions/dont-suggest-dereference-on-arg.stderr
@@ -0,0 +1,10 @@
+error: non-reference pattern used to match a reference (see issue #42640)
+  --> dont-suggest-dereference-on-arg.rs:16:19
+   |
+16 |         .filter(|&(ref a, _)| foo(a))
+   |                  ^^^^^^^^^^^ help: consider using: `&&(ref k, _)`
+   |
+   = help: add #![feature(match_default_bindings)] to the crate attributes to enable
+
+error: aborting due to previous error
+