When is a Perl 6 array clone not a clone?

Question

If I put a list in an array variable and clone it into another array variable, the two are distinct:

my @original = 1, 3, 7;
my @clone = @original.clone;

@original[*-1] = 'Dog';
say "original is finally <@original[]> ({@original.^name})";
say "clone is finally <@clone[]> ({@clone.^name})";

The output shows that they don't affect each other:

 original is finally <1 3 Dog> (Array)
 clone is finally <1 3 7> (Array)

However, if I put an Array in a scalar variable, the clone doesn't keep the two separate. Changing one changes the other:

my $original = [ 1, 3, 7 ];
say "original is <$original[]> ({$original.^name}) with {$original.elems} values";

my $clone = $original.clone;
say "clone is <$clone[]> ({$clone.^name}) with {$clone.elems} values";

if $original eqv $clone {
    say "The original and clone have the same values!";
    }

if $original === $clone {
    say "The original and clone are the same object!";
    }

if $original =:= $clone {
    say "The original and clone are the same container!";
    }

$original[*-1] = 'Dog';
say "original is finally <$original[]> ({$original.^name}) with {$original.elems} values";
say "clone is finally <$clone[]> ({$clone.^name}) with {$clone.elems} values";

The output shows that the original and the clone are still linked, but curiously they aren't the same object or container:

 original is <1 3 7> (Array) with 3 values
 clone is <1 3 7> (Array) with 3 values
 The original and clone have the same values!
 original is finally <1 3 Dog> (Array) with 3 values
 clone is finally <1 3 Dog> (Array) with 3 values

This one works, where the clone is assigned to an array variable:

my $original = [ 1, 3, 7 ];
my @clone = $original.clone;

$original[*-1] = 'Dog';
say "original is finally <$original[]> ({$original.^name})";
say "clone is finally <@clone[]> ({@clone.^name})";

But when the original is an array and the clone is assigned to a scalar variable, it doesn't work:

my @original = 1, 3, 7;
my $clone = @original.clone;

@original[*-1] = 'Dog';
say "original is finally <@original[]> ({@original.^name})";
say "clone is finally <$clone[]> ({$clone.^name})";

This is Rakudo 2017.01.

Answer 1

In Rakudo 2017.04, this is no longer a problem. I get the expected output:

original is <1 3 7> (Array) with 3 values
clone is <1 3 7> (Array) with 3 values
The original and clone have the same values!
original is finally <1 3 Dog> (Array) with 3 values
clone is finally <1 3 7> (Array) with 3 values