Casper

@dbaileychess, its almost ready. I can push the merge button once everyone LGTMs

Are we all ready to merge?

I think this is great. Thank you for this PR! @TethysSvensson @alamb any further comments? If not, I'll submit once the branch is up to date and CI is green

We need both a release of `flatc` (@dbaileychess) and the flatbuffers crate to get this change out there

I want #7553 to go in before pushing, but otherwise it can go in EoWeek

Ok, #7553 did not make it, I'll push the publish button (once I get #7574 merged)

released!

Taking over this issue to track advanced union features generally. The only documentation of what "Advanced Union Features" means seems to be https://github.com/google/flatbuffers/issues/5002#issuecomment-439182796: * Vector of Unions * String variants...

Still important

Would this flag help? https://github.com/google/flatbuffers/blob/cfe157ec5667ab2101a62889ac0f5260a0166116/src/flatc.cpp#L163