> So hmm, you’re right!  I’m sure I saw go packages somewhere, dunno…

Just looked at the source: after my Go 1.11 update, Syncthing was updated to use
vendored dependencies, just like go-ipfs.  This is why it does not contains any
go ref.  From the package declaration:

              ;; Since the update to Go 1.11, Go programs have been keeping
              ;; spurious references to all their dependencies:
              ;; <https://bugs.gnu.org/33620>.
              ;; For Syncthing, this increases the size of the 'out' closure
              ;; from 87.6 MiB to 253.5 MiB.  So, we use the bundled
              ;; dependencies until the bug is resolved.
              
So yup, "guix size" is not happy with Go...

-- 
Pierre Neidhardt
https://ambrevar.xyz/