icedtea-netx: Dependencies "not installable"

[TJ]

On 18.04, amd64:

$ sudo apt install libtagsoup-java librhino-java icedtea-netx:i386
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 icedtea-netx:i386 : Depends: default-jre:i386 but it is not going to be installed
                     Depends: libtagsoup-java:i386 but it is not installable
                     Depends: librhino-java:i386 but it is not installable
E: Unable to correct problems, you have held broken packages.

libtagsoup-java and librhino-java are architecture "all" and should be installable.

Manually installing them first is fine:

$ sudo apt install libtagsoup-java librhino-java
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
  rhino libtagsoup-java-doc
The following NEW packages will be installed
  librhino-java libtagsoup-java
0 to upgrade, 2 to newly install, 0 to remove and 87 not to upgrade.
Need to get 1,245 kB of archives.
After this operation, 1,435 kB of additional disk space will be used.
...

But after this the install of icedtea-netx:i386 still fails.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.