In #68898 I will land a mitigation that caches a sound dill separately from a non-sound dill. This only works if --sound-null-safety is specified from the command line.

If the soundness mode is autodetected, then the tool does not know whether the dill was compiled in sound or unsound mode.

There are three potential long term fixes:

• The frontend_server accounts for sound/unsound in --initialize-from-dill and recompiles accordingly
• The frontend_server communicates in some way to the tool what mode the dill was compiled in, and the tool implements additional caching logic to account for this.
• The tool disables --initialize-from-dill