Hey friends,
Just faced this issue. Any idea where may come from?

It's been dropped - https://github.com/symplify/symplify/pull/1956,
but only on master.
Better not use master until it's releasted. There is gonna be lot of changes now
Ah, it's in Rector, not here.
Temporary fix:

Let me know if you want me to open an issue there.
Working on fix: https://github.com/rectorphp/rector/pull/3376
Resolved now.
Some dependencies are still in dev-master mode, so their manual install is needed, if you need dev dependencies.
Thank you!
I'm getting the same error now with symplify/easy-coding-standard-prefixed on 7.3.18
Be sure to upgrade to v8
Most helpful comment
Be sure to upgrade to v8