Not what I said and I don't see why you make those choices mutually exclusive. You can have pattern matching without sum types and you can have sum types without pattern matching.

In fact Ruby's case/when statement is very limited form of pattern matching that can be put to great use with proper use of Structs and overloading of ===.

Erlang is probably a better example of pattern matching (complete) without formal sum types (though dialyzer has value and type alternatives)