composite type bug? Order makes difference.

[ggibson]

The following fails, unless the ordering of `tuple|string` is reversed. 
Verifying here before submitting an issue.
    
    
    type Group = tuple|string
    proc tryit(container: Group): auto =
      container
    echo tryit( (0,1,2))
    echo tryit( "012")
    
    
    Run
    
    
    Error: type mismatch: got <(int, int, int)>
    but expected one of:
    proc tryit(container: Group): auto
      first type mismatch at position: 1
      required type for container: Group
      but expression '(0, 1, 2)' is of type: (int, int, int)
    
    
    Run