1 files changed, 23 insertions, 0 deletions
diff --git a/src/test/ui/run-pass/self/string-self-append.rs b/src/test/ui/run-pass/self/string-self-append.rs
new file mode 100644
index 00000000000..cef7a93aeed
--- /dev/null
+++ b/src/test/ui/run-pass/self/string-self-append.rs
@@ -0,0 +1,23 @@
+// Copyright 2012 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.
+
+pub fn main() {
+    // Make sure we properly handle repeated self-appends.
+    let mut a: String = "A".to_string();
+    let mut i = 20;
+    let mut expected_len = 1;
+    while i > 0 {
+        println!("{}", a.len());
+        assert_eq!(a.len(), expected_len);
+        a = format!("{}{}", a, a);
+        i -= 1;
+        expected_len *= 2;
+    }
+}