Think of lexicals in a scope like having a different references each time the scope is passed at runtime.

But - like already demonstrated - the first part of the c-style for is outside the block to be implemented as a while.

More gory details?

A lexical declaration in a scope reserves - at run time - a storage place in memory which is released at the end of scope.

No release happens if the ref counter isn't 0, like when the lexical is used in a closure.

So if the last lexical was released it might happen that the ref is reused, but it's better to assume they aren't the same variable.

  DB<8> for my $x (1..3) { print \$x }
SCALAR(0x3450e50)SCALAR(0x3450e50)SCALAR(0x3450e50)
  DB<9> for my $x (1..2) { print \$x; $a = sub {$x} }
SCALAR(0x3459b20)SCALAR(0x3328238)
[download]

$x has different refs in line 9 because the first $x is captured in a closure and not relased.

Hence Perl can't reuse the reference.

HTH! :)