#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';

sub a {
    say 'sub a';
    local *_b = sub {
        say 'sub b';
    };

    _b();
}

a();

__END__

$ perl test.pl
sub a
sub b

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';

sub a {
    local *_b = sub {
	say @_;
        return 'sub b';
    };
    return _b('sub a');
}

say a();

__END__

$ perl test.pl
sub a
sub b

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';

sub a {
    local *_b = sub {
        return @_;
    };
    return _b(@_);
}

say a('sub a');

__END__

$ perl test.pl
sub a