Show more info for mismatched types

[focusaurus]

Currently for a mismatched type error the description show is just "mismatched types" which is not really much more information than "you are working on rust code and not done yet". The full cargo build output has:

error[E0308]: mismatched types
  --> src/main.rs:41:5
   |
39 |   fn block_bytes() -> [u8] {
   |                       ---- expected `[u8]` because of return type
40 |       // get some bytes to represent the block data
41 | /     env::args()
42 | |         .skip(1)
43 | |         .next()
44 | |         .unwrap_or("sample input".to_string())
45 | |         .into_bytes()
   | |_____________________^ expected slice, found struct `std::vec::Vec`
   |
   = note: expected type `[u8]`
              found type `std::vec::Vec<u8>`

Any way to show the "expected ..." messages when the cursor is on line 39 or 45?