<0>root@blade214(1)~$ cat /tmp/t.pp
class foo {
    $t=hiera('foo')
    notify { "$t": }
}

include foo
<0>root@blade214(2)~$ puppet apply /tmp/t.pp
calling module is:
/Stage[main]/Foo/Notify[calling module is: ]/message: defined 'message' as 'calling module is: '
Finished catalog run in 0.34 seconds
<0>root@blade214(3)~$ hiera foo environment=production foo=bar calling_module=foo
calling module is: foo
<0>root@blade214(4)~$ cat /home/gitsync/puppet/production/hiera/common/common.yaml
# defaults
---
foo: "calling module is: %{calling_module}"
<0>root@blade214(5)~$