1 files changed, 14 insertions, 0 deletions
diff --git a/tests/ui/self/string-self-append.rs b/tests/ui/self/string-self-append.rs
new file mode 100644
index 00000000000..e63dc0090cb
--- /dev/null
+++ b/tests/ui/self/string-self-append.rs
@@ -0,0 +1,14 @@
+// run-pass
+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;
+    }
+}