Perl6 Case insensitive use of <sym> ?

gistfile1.pl

use v6;
use Test;
grammar G {
   ## use rule :ignorecase; # nyi in rakudo. not what we want anyway
   ## use sym :ignorecase #??
   rule TOP { <prop> + }
   rule num {[\d|'.']+}
   proto rule prop {<...>}
   rule prop:sym<line-width>  {:i <sym> ':' <num> }
   rule prop:sym<line-height>:i { <sym> ':' <num> }   
}

for ('line-width: 42', 'line-height: 47',
     'LINE-WIDTH: 42', 'LINE-HEIGHT: 47'  # these don't parse
    ) {
    ok(G.parse($_), "parse: $_");
}