[masklinn]

The author specifically and explicitly pointed out 3 times in 2 paragraph that these were new to them, not to the world at large. In fact, they spelled this out very explicitely in the paragraph following the one you selectively quoted:

> Many of the new concepts weren't novel to Rust. But considering I've had exposure to many popular programming languages, the fact many were new to me means these aren't common features in mainstream languages.

And… they're right. Other languages cropped up with overlap around the same time (mostly Swift), but sum types, pattern matching, option types, … were not common features, and borrow checking remains rather unique.

[StreamBright]

He also claimed that he programmed in Erlang. How can you program in Erlang without pattern matching?