A mismatched types error in Rust

RustQuestion3

use tempo::Tempo;
use time_signature::TimeSignature;

#[deriving(Clone)]      // The error disappears if I remove this line.
#[deriving(Show)]
pub struct JTimePack<'r> {       
    sample_rate: int,            
    tempo: &'r Tempo,            
    time_sig: &'r TimeSignature,  // << Error is found here pointing to 't' in 'time_sig'
    ppqn: int                    
}

/*
The above gives me the following error,

error: mismatched types: expected '&time_signature::TimeSignature' but found 'time_signature::TimeSignature' (expected &-ptr but found struct time_signature::TimeSignature)

NOTE: I've noticed that TimeSignature derives from Clone already, however Tempo does not. Does this have something to do with it?
NOTE2: When a 'JTimePack' is cloned, I intend for the references to be copied so that both resulting 'JTimePack's point to and read from the same Tempo and TimeSignature instances.
*/

It turns out that (at this stage of the pre-nightly Rust build) "#[deriving(Clone)]" causes a de-reference during cloning (hense it found an actual TimeSignature object rather than the reference). I was informed that this would be fixed in the near future, however for now all I had to do was explicitly implement the Clone trait for my JTimePack object,

impl<'r> Clone for JTimePack<'r> {
    fn clone(&self) -> JTimePack<'r> {
        *self
    }
}