1 files changed, 41 insertions, 0 deletions

diff --git a/tests/ui/issues/issue-20055-box-trait.rs b/tests/ui/issues/issue-20055-box-trait.rs
new file mode 100644
index 000000000..772cd9d7e
--- /dev/null
+++ b/tests/ui/issues/issue-20055-box-trait.rs
@@ -0,0 +1,41 @@
+// run-pass
+// See Issues #20055 and #21695.
+
+// We are checking here that the temporaries `Box<[i8, k]>`, for `k`
+// in 1, 2, 3, 4, that are induced by the match expression are
+// properly handled, in that only *one* will be initialized by
+// whichever arm is run, and subsequently dropped at the end of the
+// statement surrounding the `match`.
+
+trait Boo {
+    fn dummy(&self) { }
+}
+
+impl Boo for [i8; 1] { }
+impl Boo for [i8; 2] { }
+impl Boo for [i8; 3] { }
+impl Boo for [i8; 4] { }
+
+pub fn foo(box_1: fn () -> Box<[i8; 1]>,
+           box_2: fn () -> Box<[i8; 2]>,
+           box_3: fn () -> Box<[i8; 3]>,
+           box_4: fn () -> Box<[i8; 4]>,
+            ) {
+    println!("Hello World 1");
+    let _: Box<dyn Boo> = match 3 {
+        1 => box_1(),
+        2 => box_2(),
+        3 => box_3(),
+        _ => box_4(),
+    };
+    println!("Hello World 2");
+}
+
+pub fn main() {
+    fn box_1() -> Box<[i8; 1]> { Box::new( [1; 1] ) }
+    fn box_2() -> Box<[i8; 2]> { Box::new( [1; 2] ) }
+    fn box_3() -> Box<[i8; 3]> { Box::new( [1; 3] ) }
+    fn box_4() -> Box<[i8; 4]> { Box::new( [1; 4] ) }
+
+    foo(box_1, box_2, box_3, box_4);
+}