weird behavior with eqv

node.pm6

use v6;

class Node does Positional
{
    has ( $.Str, @.list );

    submethod BUILD( :$node ) { @!list = ( $!Str = $node ).comb: / \D+ | \d+ / }

    method AT-POS( *@i ) { @!list[@i] }

    method cmp( Node $n )
    {
        my $i = self.ind( $n );
        $i.defined ?? @!list[$i] cmp $n[$i] !! $!Str leg $n;
    }

    method ind( Node $n )
    {
        my @i = $n.keys.grep: { @!list[$_] ne $n[$_] } if @!list == +$n;

     ## why does the line below not work with !eqv ?
     ## my @i = $n.keys.grep: { @!list[$_] !eqv $n[$_] } if @!list == +$n;
     ## say @i;  ## with input below this should be 1, not 0, 1

        return @i == 1 ?? @i[0] !! Nil;
    }
}

multi prefix:<+>( Node $n ) { $n.elems }
multi infix:<~>( Node $l, Node $r ) { Node.new: :node{ $l ~ $r } }
multi infix:<*>( Node $l, Node $r ) { $l.ind: $r }
multi infix:<cmp>( Node $l, Node $r ) { $l.cmp: $r }

my $a = Node.new( :node<abc000> );
my $b = Node.new( :node<abc001> );

say $a * $b; ## expecting 1, which is the index $a and $b have in common