Can we use a sub-task as a standard issue type or vice versa?

[ASHOK KUMAR]

Hi All, Is it possible to use a given subtask as a standard issuetype and a standard issuetype as a subtask within a same project? e.g. is it possible that 'Impediments' should appear on a create issue screen and can also be added as a subtask for the same project? please suggest. 

[Nic Brough -Adaptavist-]

No, they are two totally separate issue types.  You will need to create a standard issue type and a subtask type separately and with different names.