temp $var;

[Alexey Trofimenko]

  my $var="foo";
  {
    temp $var;
    say $var;
  }
would it be undef or "foo"? if the former, how could I make $var to  
contain a copy of original content?
using analogy with my $x = $x, that's not going to work..

  temp $var = $OUTER::var?
OTOH,
  my @a = ... # something not lazy with 10_000_000 elements..
  {
     temp @a; # ouch! temporal clone!
  }
that could hurt..