I analyzed the problem, leading to this routine:
---
create_localhost: INET_ADDRESS
                        -- (from INET_ADDRESS_FACTORY)
                        -- (export status {NONE})
                local
                        localhostname: STRING_8
                do
                        localhostname := Impl.local_host_name
                        check
                                        attached create_from_name (localhostname) as l_result
                        then
                                Result := l_result
                        end
                end
---
The problem is "Impl.local_host_name"; could it be replaced with "loopback_address.internal_host_name" (if there is no network)?
In my case the computer had no network, and the hostname did not resolve via /etc/hosts. However "localhost" would. For local connections "localhost" might be more efficient anyway, because the MTU (maximum transfer unit) is larger than when going through some Ethernet interface.
An alternative (for a work-around by the user) would be to add 127.0.0.2 to the "lo" interface, and then add an entry to /etc/hosts resolving the hostname to 127.0.0.2. Eventually I did the second step without the first, and that fixed the problem (that EiffelStudio could handle much better than quitting).