No, but how do you pass "mutable locals" to other processes? That's the whole question. If you pass a "local" on a channel to a different goroutine, Go can't g

No, but how do you pass "mutable locals" to other processes? That's the whole question. If you pass a "local" on a channel to a different goroutine, Go can't guarantee to the receiver (which now has it as a "local" variable) that the sender (which still has it as a "local") won't change it: d := map[string]int{} ch <- d d["foo"] = 42 // Oops! The only way to do this safely is to to write a channel abstraction which uses gob or similar to marshal and unmarshal all data, thus copying it and preventing concurrent mutation, and then always use the channel abstraction. But always copying tends to be terrible for performance. Erlang is able to do zero-copy sends to process mailboxes because the data is guaranteed to be immutable. Sure, you could instead mandate that senders never hold on to data sent on channels, but can you ensure this 100% across a codebase contributed to by an entire team?