Ah … but then it only works if you propagate the EC either implicitly (when using Futures), or if you use the same EC to execute all of the tasks (without shifting to other ones).

Wouldn’t probably work for me, as I usually just use the global EC everywhere and delegate to specialised ECs for DB, network or other blocking operations.

So in a single call-chain multiple unrealted ECs might be used. On the good side, there’s no implicit ec: ExecutionContext everywhere ;)