use signatures;
my $lamb = sub ($x, $y) { $x + $y };
print( $lamb->(3,4), "\n" );  # 7

##</code><code>##

use signatures;
my $lamb = sub ($x) { $x = 4 };
my $y = 3;
$lamb->($y);
print("$y\n");  # 3  XXX want 4

##</code><code>##

sub (...) { ... }

##</code><code>##

sub { my (...) = @_; ... }

##</code><code>##

Lexical::Alias::alias(my $x, $_[0]);
Lexical::Alias::alias(my $y, $_[1]);
Lexical::Alias::alias(my $z, $_[2]);