Statically typing the underlying message passing model used in Erlang is pretty hard, because the mailbox of a process can accept any type of message. And so, it cannot be statically typed in general, since anyone who holds a process id can shove a message into that mailbox.

In contrast, Go's message passing model works on typed channels. A channel has a type, and only accepts messages of the given type. The `receive` operator then acts as the merging data flow which solves the problem of receiving messages of different types. This is a design which amends itself far better to static typing.

Pattern matching isn't a substitute for static typing at all. The two features are entirely orthogonal indeed, and you definitely want static typing and pattern matching at the same time.