don't pass mut references unless you need to

Author: danieleades

async-byte-channel/src/lib.rs

@@ -176,7 +176,7 @@ pub mod test {
         drop(receiver);
 
         let mut pool = futures::executor::LocalPool::new();
-        let result = pool.run_until(sender.write_all(&mut [0,1,2]));
+        let result = pool.run_until(sender.write_all(&[0,1,2]));
         assert!(result.is_err());
     }
 }

capnp/src/any_pointer.rs

@@ -239,7 +239,7 @@ fn init_clears_value() {
     }
 
     let mut output: Vec<u8> = Vec::new();
-    crate::serialize::write_message(&mut output, &mut message).unwrap();
+    crate::serialize::write_message(&mut output, &message).unwrap();
     assert_eq!(output.len(), 40);
     for byte in &output[8..] {
         // Everything not in the message header is zero.