Not as general or useful as Rust's "if let", though. Rust's "if let" affords fallible pattern matching on arbitrary types, not just on "nullable pointer types" (in Safe Rust, a "nullable pointer" is simply a regular reference wrapped in Option<>).
Swift has "if case let" for that use case. (Admittedly, the syntax is a bit esoteric.)
Worth noting that we got the idea for if let from Swift :)
These are the little things I love seeing on HN. :)