$array[$x]->{"foo"}->[0] = "January";
$array[$x]{"foo"}[0] = "January";
but
$array->[$x]{"foo"}[0] = "January"; (WRONG, as array is not a ref)

${$arrayref}[0]     =  ${$arrayref}->[0]     =  $arrayref->[0]    = "January";  
${$hashref}{"KEY"}  =  ${$hashref}->{"KEY"}  =  $hashref->{"KEY"} = "VALUE";

${$coderef}(1,2,3)  = ${$coderef}->(1,2,3)  =  $coderef->(1,2,3)     Subroutine call or method object 


${$aref}[3]   $aref->[3] instead.
${$href}{red} $href->{red}

For scalar only, recommended
Compare
                    ${$aref} [3]
                      $aref->[3]

                    ${$href} {red}
                      $href->{red}

replace             ${     }
by                         ->

As we can see it can only work with scalar dereferencing @array = @{$array_ref}

$objref   = new Doggie( Tail => 'short', Ears => 'long' );
$objref   = Doggie->new( Tail => 'short', Ears => 'long' ); (recommended)