add testcase for #3462

tests/run-pass/ice-3462.rs

@@ -0,0 +1,30 @@
+// Copyright 2014-2019 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// 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.
+
+#![warn(clippy::all)]
+#![allow(clippy::blacklisted_name)]
+#![allow(unused)]
+
+enum Foo {
+    Bar,
+    Baz,
+}
+
+fn bar(foo: Foo) {
+    macro_rules! baz {
+        () => {
+            if let Foo::Bar = foo {}
+        };
+    }
+
+    baz!();
+    baz!();
+}
+
+fn main() {}