auto merge of #15191 : pcwalton/rust/variance-in-trait-matching, r=huonw

I believe that #5781 got fixed by the DST work. It duplicated the
variance inference work in #12828. Therefore, all that is left in #5781
is adding a test.

Closes #5781.

r? @huonw

2 files changed, 9 insertions, 4 deletions

diff --git a/src/libstd/io/comm_adapters.rs b/src/libstd/io/comm_adapters.rs
index c03fbf302d7..cd5887b7add 100644
--- a/src/libstd/io/comm_adapters.rs
+++ b/src/libstd/io/comm_adapters.rs
@@ -183,7 +183,10 @@ mod test {
         writer.write_be_u32(42).unwrap();
 
         let wanted = vec![0u8, 0u8, 0u8, 42u8];
-        let got = task::try(proc() { rx.recv() }).unwrap();
+        let got = match task::try(proc() { rx.recv() }) {
+            Ok(got) => got,
+            Err(_) => fail!(),
+        };
         assert_eq!(wanted, got);
 
         match writer.write_u8(1) {
diff --git a/src/libstd/task.rs b/src/libstd/task.rs
index dad241002f8..8ccded6681b 100644
--- a/src/libstd/task.rs
+++ b/src/libstd/task.rs
@@ -630,9 +630,11 @@ mod test {
         let mut reader = ChanReader::new(rx);
         let stdout = ChanWriter::new(tx);
 
-        TaskBuilder::new().stdout(box stdout as Box<Writer + Send>).try(proc() {
-            print!("Hello, world!");
-        }).unwrap();
+        let r = TaskBuilder::new().stdout(box stdout as Box<Writer + Send>)
+                                  .try(proc() {
+                print!("Hello, world!");
+            });
+        assert!(r.is_ok());
 
         let output = reader.read_to_str().unwrap();
         assert_eq!(output, "Hello, world!".to_string());