The following bug has been logged on the website:
Bug reference: 10692
Logged by: Pontus Lundkvist
Email address: p(at)article(dot)se
PostgreSQL version: 9.4beta1
Operating system: Debian sid
Description:
Trying to connect to another database via \c and a service-definition,
it seems to ignore everything other than the dbname. This includes not
using either user or host.
For a service-definition without dbname, it seems to act just like an
empty \c, reconnecting to the same connection.
Expected result: Either oblivious to service=-dsn and failing hard,
or that the full service-definition is parsed and used.