can someone explain this in a more layman way? I have still many doubts:

• (1) $x = 'a' x (2**32) provokes the wrong behavior. I read RHS is compile-time constant so what I understand is that Right Hand Side expression is evaluated during compile time. But why doubles the memory used? And why 2**${\32} forces it to be posponed to runtime? And why the latter does not double the memory?
• (2) COW aka Copy On Write should be the default in an assignement and this should prevent the memory to be doubled. So in this case is effectively a bug?
• (3) in the two snippets I posted here I cannot spot any real difference in the assignement but they behaves differently. Why?

# wrong beaviour as it doubles the memory
# first code of my previous post, very similar to the OP one
my $x = 'a' x (2**30); 


# RIGHT beaviour, it does NOT double memory used
# second code posted above 
my $x; 
foreach my $order ( qw(20 24 30 32) ){
    $x = 'a' x ( 2 ** $order );
    ...

# RIGHT beaviour, even with my $x declared inside the foreach loop
foreach my $order ( qw(20 24 30 32) ){
    my $x = 'a' x ( 2 ** $order );
        ...
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In addition every perl I have atm ( strawberry portable: 5.26.0 5.22.3 5.24.2 5.26.2 ) I observe the same beahviours of the two above programs, ie. doubled and not doubled; I read also Linux users experience the same. So it must be something really bound to Perl itself and I'd like to know why and how to prevent this: a doubled memory footprint is not such a great feauture to have :)

L*