Snap packages as build dependencies of other snaps

[Joseph Rushton Wakeling]

Hello folks,

Is it possible to specify an existing snap package (by track and release 
channel) as a build dependency of a part of another snap package?

I'm interested specifically in the case of using an existing snap package to 
provide a compiler used to build another snap.  From what I understand from 
discussion around the go snapcraft plugin, there is some intention to allow 
this, but is it just for plugins?

Thanks & best wishes,

     -- Joe