Add regression test for single field by val tuples

diff --git a/tests/run-pass/issue-20575.rs b/tests/run-pass/issue-20575.rs
new file mode 100644 (file)
index 0000000..7db7e3b
--- /dev/null
+++ b/tests/run-pass/issue-20575.rs
@@ -0,0 +1,19 @@
+// Copyright 2015 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.
+
+// Test that overloaded calls work with zero arity closures
+
+// pretty-expanded FIXME #23616
+
+fn main() {
+    let functions: [Box<Fn() -> Option<()>>; 1] = [Box::new(|| None)];
+
+    let _: Option<Vec<()>> = functions.iter().map(|f| (*f)()).collect();
+}