my %baz;
$baz{$_->[0]}{foo} = $_->[1] for @foo;
$baz{$_->[0]}{bar} = $_->[1] for @bar;

my @baz;
for my $k (sort keys %baz) {
    push @baz, [ $k, @{$baz{$k}}{qw(foo bar)} ];
}
use Data::Dump 'dump';
print dump(\@baz);